Flow Measurement Units-What Is GPM in Flow Meter?

What Is GPM in Flow Meter?

GPM is the abbreviation for gallons per minute and is used to indicate the volume of liquid flowing through a pipe diameter in one minute. Is a unit of measurement used in flow meters. Essentially, it tells you how many gallons of liquid are moving through the pipe per minute. GPM is widely used in a variety of industries and applications such as water supply systems, irrigation and fluid transfer. Understanding GPM in a flow meter is important for both selecting and using a flow meter.

 GPM in Flow Meter

flow measurement units

In the world of flow meters, various units of measurement are used to quantify the flow of liquids or gases. These units help to ensure precise flow control and monitoring across industries. Let’s take a look at some of the commonly used flow meter units:

Gallons per Minute (GPM): As we discussed earlier, GPM is a popular unit for measuring liquid flow, especially in the United States, where the imperial system is widely used.

Liters per Minute (LPM): LPM is another unit for measuring liquid flow, commonly used in countries that follow the metric system. One GPM is approximately equal to 3.785 LPM.

Cubic Meters per Hour (m³/h): This unit measures the volume of gas or liquid flow per hour and is often used in large-scale applications, such as water supply networks and industrial processes.

Standard Cubic Feet per Minute (SCFM): SCFM is a unit for measuring gas flow rates. It represents the volume of gas flowing per minute, corrected to standard conditions of temperature and pressure.

Cubic Feet per Minute (CFM): Similar to SCFM, CFM is a unit for measuring gas flow rates, but without adjusting for temperature and pressure.

By understanding these commonly used flow meter units, you can better select and utilize flow meters for your specific application, ensuring accurate measurements and optimal performance.

Flow Unit Conversion Table

GPM LPM L/h M3/h
1 3.785 227.1 0.227
5 18.925 1135.5 1.135
10 37.85 2271 2.271

More about:

GPM Flow Meters

GPM Flow Meters specifically refers to a type of flow meter that can use GPM as the flow indication unit. Sino-Inst’s flow rate is basically equipped with a smart display, and the flow display unit can be set and adjusted. Such as GPM, USG, L/h, Kg/h, etc.

Flow meters with GPM units are widely used to measure liquid flow in various industries. Some popular types of flow meters that measure in GPM include:

Model Measure Range
GF02 0.6-50 0.0026-0.2201
GF04 5-250 0.0220-1.1007
GF06 10-500 0.0440-2.2014
GF10 50-1200 0.2201-5.2834
GF15 200-3000 0.8806-13.2088
GF25 1000-12000 4.4029-52.8340
GF32 2000-20000 8.8057-105.6680

Read more about: Top Flow Meters for PVC Pipes: Find Your Ideal Match

Diameter (mm) Normal flow range (m3/h) Normal flow range (GPM) Extended flow range(m3/h) Extended flow range (GPM)
DN 4 0.04-0.25 0.176-1.1 0.04-0.4 0.176-1.76
DN 6 0.1-0.6 0.44-2.64 0.06-0.6 0.264-2.64
DN 10 0.2-1.2 0.88-5.28 0.15-1.5 0.66-6.6
DN 15 0.6-6 2.64-26.4 0.4-8 1.76-35.2
DN 20 0.8-8 3.52-35.2 0.45-9 1.98-39.6
DN 25 1-10 4.4-44 0.5-1 2.2-4.4
DN 32 1.5-15 6.6-66 0.8-15 3.52-66
DN 40 2-20 8.8-88 1-20 4.4-88
DN 50 4-40 17.6-176 2-40 8.8-176
DN 65 7-70 30.8-308 4-70 17.6-308
DN 80 10-100 44-440 5-100 22-440
DN 100 20-200 88-880 10-200 44-880
DN 125 25-250 110-1100 13-250 57.2-1100
DN 150 30-300 132-1320 15-300 66-1320
DN 200 80-800 352-3520 40-800 176-3520
Nominal diameter(DN mm) Minimum flow measurement range (m3/h) Maximum flow measurement range (m3/h) Min flow range (GPM) Max flow range (GPM)
15 0.06 6.36 0.264 28
20 0.11 11.31 0.485 49.78
25 0.17 17.67 0.748 77.77
32 0.28 28.94 1.234 127.43
40 0.45 45.23 1.984 199.02
50 0.71 70.68 3.127 311.21
65 1.19 119.45 5.241 525.64
80 1.81 180.95 7.968 796.97
100 2.82 282.74 12.41 1244.4
125 4.41 441.71 19.42 1944.12
150 6.36 636.17 27.99 2801.58
200 11.31 1130.97 49.78 4978.68
250 17.67 1767.14 77.77 7776.3
300 25.44 2544.69 111.95 11195.44
350 34.63 3463.6 152.55 15255.28
400 45.23 4523.89 199.02 19902.66
450 57.25 5725.55 251.96 25196.66
500 70.68 7068.58 310.98 31098.28
600 101.78 10178.76 448.06 44805.98
700 138.54 13854.42 609.35 60935.07
800 180.95 18095.57 796.97 79697.23
Nominal Diameter (mm) Flow Range (m3/h) Flow Range (GPM)
10 0.02 – 0.2 0.0881 – 0.8806
15 0.075 – 0.75 0.3302 – 3.3022
20 0.15 – 1.5 0.6604 – 6.6043
25 0.3 – 3 1.3209 – 13.2086
40 0.75 – 7.5 3.3022 – 33.0215
50 1.2 – 12 5.2834 – 52.8344
80 3-30 13.2086 – 132.0862
100 5 – 50 22.0143 – 220.1435
150 9.5 – 95 41.8272 – 418.2724
200 17.4 – 174 76.6099 – 766.0991

Of course, in addition to the above several flowmeters. Other flow meters can also support GPM unit display. Such as ultrasonic flowmeter, mass flowmeter and so on.

Online Flow Measurement Units Converter Tools

Mass Flow & Density to Volume Flow CalculatorMass Flow Rate Unit ConverterVolume Flow Rate Converter
Volume Flow & Density to Mass Flow CalculatorVolumetric Flow Rate & Pipe Diameter to Flow Speed Calculator


GPM stands for gallons per minute, and it’s a measurement of the flow rate of water through a water meter. It tells you how many gallons of water are passing through the meter every minute. GPM is commonly used in the United States to measure water flow rates in residential, commercial, and industrial applications.

Reading a GPM flow meter is pretty straightforward. First, locate the flow rate indicator on the meter, usually displayed as a dial or digital readout. The number shown represents the flow rate in gallons per minute (GPM). Some meters might display the flow rate in liters per minute (L/min) or cubic meters per hour (m3/h). In these cases, you can convert the values to GPM using a conversion factor (1 L/min = 0.264172 GPM, 1 m3/h = 4.40287 GPM).

Flow Meter Selection Guide 101: Find the Perfect Fit for Your Application

The GPM for a 3/4-inch water meter can vary based on factors like water pressure and the meter’s specific design. Generally, a 3/4-inch water meter can handle a flow rate of around 10 to 30 GPM. To find the exact GPM for your 3/4-inch water meter, you can check the manufacturer’s specifications or consult with a plumber.

More Flow Meter Markets and Applications

In conclusion, understanding flow rates and water meter sizes is essential for effective water management, whether you’re a homeowner, business owner, or engineer. GPM, or gallons per minute, is a widely used measurement to indicate the flow rate of water through a meter. By knowing how to read your flow meter and understanding the GPM values for different water meter sizes, you can make more informed decisions about your water usage.

We, Sino-Inst, pride ourselves on being a professional flowmeter supplier with years of experience in the industry. We offer a wide range of flowmeters suitable for various applications, ensuring that you get the perfect solution for your water management needs. So, don’t hesitate to reach out to us for expert advice, top-quality products, and outstanding customer service.

Ready to upgrade your flow meter or need help selecting the right one? Give us a call or visit our website to browse our extensive selection of flowmeters and find the perfect match for your needs. Let Sino-Inst be your go-to partner for all things related to flow measurement and water management.

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What Is a BTU Meter?

What is a BTU Meter?

A BTU meter is a special instrument that measures the thermal energy transferred in a heating or cooling system. BTU meters are also known as energy meters, heat meters. Commonly used are electromagnetic energy meters and ultrasonic energy meters. It is widely used in online metering of central air-conditioning cooling and heating energy metering and heating network. It can also be used to measure the performance of energy conservation measures or the loss of system efficiency that affects revenue.

RFQ More Flowmeters

Featured Flow and BTU Meters

What is BTU?

BTU (British Thermal Unit). 1BTU is approximately equal to 252.1644 calories (calorie) = 0.293 watt-hour (watt-hour) = 1.055 kilojoules (killojoule)

1 BTU is the amount of heat required to heat 1 pound of pure water from 59 degrees Fahrenheit to 60 degrees Fahrenheit at an atmospheric pressure of 14.696 pounds per square inch. ​​

Btu is British Thermal Unit (British Thermal Unit) and Btu/h is “British Thermal Unit per hour”. Since 1(British Thermal Unit) = 1055.056(Joule), and 1 Watt = 1 Joule/Sec. ​​

So 1 (Btu per second) = 1055.056 (Watts), converting seconds to hours is: 1 BTU per hour = 1055.056/3600 = 0.293071 (Watts). ​​

Therefore, the power of an air conditioner with a (BTU/H) of 10000 is 10000*0.293 = 2.93 (kW).

BTU Meter Working Principle

When the water flows through the system, according to the flow rate given by the flow sensor and the temperature signal of the supply and return water given by the paired temperature sensor, as well as the time that the water flows. Calculate and display the heat energy released or absorbed by the system through the calculator.

Its basic formula is as follows:

In the formula:

Q—the heat released or absorbed by the system, J;
qm flow through heat meter
The mass flow of water, kg/h;
qv is the volume flow of water passing through the heat meter, m5/h;
ρ Density of water passing through the heat meter, ks/m3;
△h—the difference in the enthalpy of water at the inlet and outlet temperatures of the heat exchange system, J/kg;
T a time, h.

From the working principle of the heat meter, it can be seen that the heat meter is mainly divided into three parts: the base meter, the temperature sensor and the totalizer.

The base meter refers to the meter that measures the flow and converts the flow information into electrical signals.

The temperature sensor refers to a sensor that measures the temperature of the supply and return water of the heat exchange system.

The totalizer is a device that integrates and displays heat according to the formula.

Video source: https://www.youtube.com/watch?v=keD50bX1mec

BTU meter calculations are based on the measurement of flow rate and temperature difference in a heat transfer system. We now take a chilled water system as an example, and we want to calculate the amount of energy used for cooling.

Starting Data:

Flow rate of chilled water: 500 gallons per minute (GPM).
Inlet water temperature (before cooling): 70°F.
Outlet water temperature (after cooling): 50°F.

BTU Meter Calculation Steps:

  • Measure Temperature Difference: Calculate the difference in temperature between the inlet and outlet, which is 70°F – 50°F = 20°F.
  • Calculation Formula: The BTU calculation formula is BTU = Flow Rate (in lbs) x Temperature Difference x Specific Heat of Water. The specific heat of water is approximately 1 BTU/lb°F.
  • Convert Flow Rate to Weight: Convert the flow rate from gallons per minute to pounds per minute. Since water weighs about 8.34 pounds per gallon, the conversion for 500 GPM is 500 x 8.34 = 4170 lbs/min.
  • Final BTU Calculation: Plug the values into the formula:BTU = 4170 lbs/min x 20°F x 1 BTU/lb°F, which equals 83,400 BTU/min.

The industrial cooling system uses 83,400 BTUs per minute to cool the machinery and processes.

BTU Measurement System

BTU measurement systems are an important component in the pursuit of energy efficiency and sustainability in heating and cooling systems.

Define BTU measurement system:

BTU measurement systems are an important tool for understanding and managing energy in heating and cooling systems. At its core, the system relies on the British Thermal Unit (BTU), a unit of measurement of heat energy. 1 BTU represents the amount of energy required to raise the temperature of one pound of water by one degree Fahrenheit.

Components of a BTU measurement system:

A key component of this system is the BTU meter. Measure the flow rate and temperature difference of a liquid passing through a heat exchanger.

The system includes:

  • Two temperature sensors: installed at the inlet and outlet of the heat exchanger to measure the temperature difference.
  • Flow sensor: This component tracks the flow of liquid through the heat exchanger, which is a key part of energy calculations.
  • Calculator: It processes data from temperature and flow sensors to provide accurate calculations of heat energy transfer.

Applications beyond the basics

BTU measurement systems have uses far beyond basic temperature and flow measurements:

  • Energy Consumption Monitoring: It provides a detailed view of system energy usage, enabling smarter, more cost-effective decisions.
  • HVAC System Optimization: Ensure your heating and cooling systems are running at peak performance by pinpointing inefficiencies.
  • Leak and inefficiency detection: The system can alert on leaks or inefficiencies, preventing energy loss and potential system damage.
  • Improvement identification: It plays a key role in identifying areas where energy consumption can be reduced, promoting sustainable practices.

BTU Meter Types

There are different types of BTU meters, each suited for specific applications and system requirements.

The mechanical heat meter is mainly based on the impeller heat meter. Its working principle is to measure the flow rate of the heat medium by measuring the speed of the impeller, and then measure the heat value.

Turbine Meters: These meters use a rotating turbine to measure the flow rate of the fluid. The turbine’s rotational speed is proportional to the flow rate, providing a direct measurement of energy transfer.

Vortex Meters: Vortex meters detect vortices that are created when a fluid flows past an obstruction. The number of vortices is proportional to the flow rate and is used to calculate energy usage.

The ultrasonic heat meter uses a pair of ultrasonic energy exchange energy to send and receive ultrasonic waves alternately (or simultaneously). By observing the propagation time difference between the forward and reverse flow of the ultrasonic waves in the medium, the flow rate of the fluid is indirectly measured. The flow rate is then used to calculate the flow rate. Then calculate the heat value.

Clamp-On Meters: These meters use external sensors that are clamped onto the pipe. They measure the flow rate using ultrasonic signals, which is non-intrusive and causes no disruption to the system.

Inline Meters: Inline ultrasonic meters are installed within the pipeline. They offer high accuracy and are ideal for systems where a non-intrusive setup is not critical.

The main features of the ultrasonic heat meter are that there is no mechanical impeller rotation and no mechanical wear. The maintenance cost is low for later use. The service life is much longer than that of the mechanical heat meter. The flow measurement accuracy is high and the measurement reliability is good.

Electromagnetic heat meter is a measuring instrument that measures the heat released by the heat transfer fluid in the heat exchange system. A high-precision and high-reliability electromagnetic flowmeter is used as a flow meter. At the same time, a high-precision, high-stability platinum heat meter is used The resistance is used for temperature measurement. The thermal energy meter has excellent measurement performance.

At present, the electromagnetic heat meters used in the market are mainly integrated electromagnetic heat meters. Its main feature is to improve the measurement accuracy. It increases the reliability and stability of the product. It is free of debugging and maintenance. It is easy to install, But the price is relatively high.

Orifice Plate Meters: These meters use an orifice plate to create a pressure drop, which is measured to determine the flow rate.

Venturi Meters: Similar to orifice plate meters, but use a venturi tube to create a pressure drop. They are more efficient and have a lower pressure drop compared to orifice plates.

BTU Meter for Chilled Water

A BTU (British Thermal Unit) meter for chilled water is a specialized device used in cooling systems, particularly in HVAC (Heating, Ventilation, and Air Conditioning) applications. Its primary function is to measure the energy consumed in cooling processes by calculating the heat removed from the chilled water

The BTU meter consists of a flow measurement sensor, two temperature sensors, and a microprocessor-based energy calculator.

The flow sensor should be installed in the chilled water return line, and the chilled water flow direction should be installed in a vertical or horizontal position. Two temperature sensors, one sensor is installed on the oil return line. The second sensor is installed on the water supply line. The thermal energy transferred from the cooling water to the consumer over a specified period of time is proportional to the temperature difference between the flow and return flow and the amount of cooling water flowing through.

Sino-Inst offers two types of BTU meters, one with ultrasonic measurement technology (ultrasonic BTU meter) and the other with electromagnetic measurement technology (electromagnetic BTU meter).

BTU meters are widely used in:

  • Building HVAC Systems: In large buildings, accurate measurement of chilled water energy use is crucial for efficient system operation and cost allocation.
  • Industrial Cooling Processes: Industries that require precise temperature control rely on these meters for energy management and to ensure optimal operation of cooling equipment.
  • District Cooling Systems: They are also essential in district cooling systems, where chilled water is supplied to multiple buildings from a central plant.

Benefits of Using BTU Meters in Chilled Water Systems:

  • Energy Efficiency: By providing accurate energy usage data, these meters help in optimizing the operation of cooling systems, leading to energy savings.
  • Cost Allocation: In multi-tenant buildings, BTU meters enable fair billing based on actual energy usage for cooling.
  • System Monitoring and Maintenance: Regular readings from these meters can indicate system performance and help in early detection of issues.

Whether in a commercial, industrial or residential environment, a chilled water system’s BTU meter is an important tool in managing the cooling process.

BTU Meter Installation

The installation requirements for electromagnetic heat meters and ultrasonic heat meters vary.

Personally recommend the Clamp-On ultrasonic heat meter. Because the installation is the easiest.

Clamp-On ultrasonic sensors and external clamp-on temperature sensors are available. Installation is simple and low cost.

About the installation of electromagnetic heat meter. You May refer to the following PDF.

bTU meter vs flow meter

Both BTU meters and flow meters have their own importance. BTU meters help keep heating and cooling systems efficient, while flow meters ensure the correct movement of fluids through various systems.

FeatureBTU MeterFlow Meter
Primary FunctionMeasures energy usage in heating or cooling systems.Measures the volume or speed of a fluid (like water or gas).
Measurement TypeCalculates energy by assessing temperature change and flow rate.Measures the amount or flow rate of the fluid passing through it.
Typical Use CasesUsed in HVAC systems (heating, ventilation, and air conditioning), for efficiency monitoring in heating or cooling processes.Used in various industries, including water treatment, chemical processing, and residential water systems.
Key Information ProvidedProvides data on heat energy added or removed, crucial for energy management.Provides data on the quantity or speed of fluid, important for volume control and monitoring.
ComplexityGenerally more complex, as it combines flow measurement with thermal energy calculation.Simpler in operation, focusing solely on fluid flow measurement.
ImportanceEssential for energy efficiency and cost management in temperature control systems.Critical for managing and monitoring fluid flow in diverse applications.

Understanding the differences can help you choose the right tool for the job. If you need to know how well your heating or cooling is working, a BTU meter is your first choice. But if you just need to know how much water or gas is flowing, then a flow meter is what you need.


1 btu per (square meter) =1 055.05585 kg / s2


BTU = Flow Rate In GPM (of water) x (Temperature Leaving Process – Temperature Entering Process) x 500.4*Formula changes with fluids others than straight water.

BTU Calculator Tool

BTU is short for British Thermal Unit, a unit of measurement that shows just how much energy your air conditioner uses to remove heat from your home within an hour. It may seem overly technical, but BTU is an important metric that can help you determine the kind of air conditioner you need for a home your size.

Flow meters measure flow, and heat meters measure heat. The heat meter consists of an integrator (calculator), a flow meter, and a pair of temperature sensors. The first detection is the supply/return water temperature and flow rate, and then the integrator is used to calculate the heat. The basic principle is Q=Cm△t.

Compared with thermistors, platinum resistors have the advantages of accurate measurement and small resistance drift. Therefore, general heat meters use pairs of platinum resistors as temperature sensors. Usually there are PT100, PT500, and PT1000, with PT1000 being the most common (i.e. At 0℃, the resistance value is 1000Ω)

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Sino-Inst offers over 10 BTU Meter products. About 60% of these are ulrtasonic flow meters. 40% are magnetic meters.

A wide variety of BTU Meter options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of BTU Meters, located in China.

The top supplying country is China (Mainland), which supply 100% of the BTU Meter respectively.

You can ensure product safety by selecting from certified suppliers, with ISO9001, ISO14001 certification.

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Flow Rate and Pressure Relationship-How to Calculate?

Once the piping system is identified, there are 2 main types of pressure and flow relationships in the piping system: Pressure in the piping system will generally cause an increase in flow, but the exact relationship may vary depending on the major sources of resistance in the system. For many systems where frictional resistance dominates, the relationship between pressure drop and flow is quadratic.

In fluid dynamics, the flow rate and pressure are two fundamental parameters that describe how fluids (like liquids and gases) move through systems like pipes, valves, and pumps.

To understand the relationship between flow and pressure, we need to understand what flow and pressure are, how to work out the flow rate from the differential pressure, and what flow meters are used.

Pressure vs Flow vs Pipe Diameter

What is Pressure?

Pressure: This refers to the force exerted by the fluid per unit area. It is denoted by the symbol P and is typically measured in units like Pascals (Pa), bars, or pounds per square inch (psi).

What is Flow?

Flow: This refers to the volume of fluid that passes through a given surface or point per unit of time. It is often represented by the symbol Q and commonly measured in units such as liters per minute (L/min) or cubic meters per hour (m^3/h).

Flow is also divided into mass flow and volume flow. When the amount of fluid is expressed by volume, it is called volume flow. When the amount of fluid is expressed by mass, it is called mass flow.

Extended reading: Mass Flow Rate vs Volumetric Flow Rate

What is Pipe Diameter?

The pipe diameter means that when the pipe wall is relatively thin, the outside diameter of the pipe is almost the same as the inside diameter of the pipe. So the average value of the outside diameter of the pipe and the inside diameter of the pipe is taken as the pipe diameter.

Usually refers to the general synthetic material or metallic pipe. And when the inner diameter is large, the average value of the inner diameter and the outer diameter is taken as the pipe diameter.

Based on the metric system (mm), it is called DN (metric unit).

Does pressure affect flow?

Yes, pressure does affect flow. But this effect is affected by many factors, such as the resistance of the system, the flow pattern, the properties of the fluid, etc. When designing and operating fluid systems, these factors need to be considered to ensure efficient and safe operation of the system.

flow rate and pressure relationship

First of all, flow = flow rate × pipe inner diameter × pipe inner diameter × π÷4. Therefore, the flow and the flow rate basically know one to calculate the other parameter.

But if the pipe diameter D and the pressure P in the pipe are known, can the flow rate be calculated?

The answer is: It is not yet possible to find the flow velocity and flow rate of the fluid in the pipeline.

You imagine that there is a valve at the end of the pipe. When closed, there is pressure P in the tube. The flow rate in the tube is zero.

Therefore: The flow rate in the pipe is not determined by the pressure in the pipe, but by the pressure drop gradient along the pipe. Therefore, it is necessary to indicate the length of the pipeline and the pressure difference between the two ends of the pipeline in order to find the flow rate and flow rate of the pipeline.

Extended Reading: Magnetic Battery Operated Flow Meter

If you look at it from a qualitative analysis point of view. The relationship between pressure and flow in the pipeline is proportional. That is, the greater the pressure, the greater the flow rate. The flow rate is equal to the velocity multiplied by the section.

For any section of the pipeline, the pressure comes from only one end. That is to say, the direction is one-way. When the outlet in the pressure direction is closed (valve closed). The fluid in the tube is prohibited. Once the exit opens. Its flow rate depends on the pressure in the pipeline.

Extended reading: High accuracy pressure transducers

For quantitative analysis, you can use hydraulic model experiments. Install pressure gauges, flow meters, or measure flow-through capacity. For pressure pipe flow, it can also be calculated. The calculation steps are as follows:

  1. Calculate the specific resistance S of the pipeline. If it is an old cast iron pipe or old steel pipe. The specific resistance of the pipeline can be calculated by Sheverev formula s=0.001736/d^5.3 or s=10.3n2/d^5.33. Or check the relevant form;
  2. Determine the working head difference H=P/(ρg) at both ends of the pipeline. If there is a horizontal drop h (referring to the beginning of the pipe higher than the end by h).
    Then H=P/(ρg)+h
    In the formula: H: take m as the unit;
    P: is the pressure difference between the two ends of the pipe (not the pressure of a certain section).
    P is in Pa;
  3. Calculate the flow rate Q: Q = (H/sL)^(1/2)
  4. Flow rate V=4Q/(3.1416 * d^2)
    1. In the formula: Q —— flow rate in m^3/s;
    2. H —— The head difference between the beginning and the end of the pipeline, in m;
    3. L —— The length from the beginning to the end of the pipe, in m.

Extended reading: Insertion Ultrasonic Water Flow Meter – Designed for Agricultural Irrigation, Garden Management

Extended reading: High Pressure Flow Meters for Liquids-Steam-Gas

Flow Rate and Pressure Formula

Mention pressure and flow rate. I think many people will think of Bernoulli’s equation.

Daniel Bernoulli first proposed in 1726: “In water or air currents, if the velocity is low, the pressure is high. If the velocity is high, the pressure is small”. We call it “Bernoulli’s Principle”.

This is the basic principle of hydraulics before the continuum theory equation of fluid mechanics is established. Its essence is the conservation of fluid mechanical energy. That is: kinetic energy + gravitational potential energy + pressure potential energy = constant.

Extended reading: Fluid flow meter types

Have to be aware of it. Because the Bernoulli equation is derived from the conservation of mechanical energy. Therefore, it is only suitable for ideal fluids with negligible viscosity and incompressible.

Bernoulli’s principle is often expressed as:

This formula is called Bernoulli’s equation.

  • p is the pressure of a certain point in the fluid;
  • v is the flow velocity of the fluid at that point;
  • ρ is fluid density;
  • g is the acceleration of gravity;
  • h is the height of the point;
  • C is a constant.

It can also be expressed as:


To use Bernoulli’s law, the following assumptions must be met before it can be used. If the following assumptions are not fully met, the solution sought is also an approximation.

  • Steady flow: In a flow system, the nature of the fluid at any point does not change with time.
  • Incompressible flow: the density is constant, when the fluid is a gas, the Mach number (Ma)<0.3 is applicable.
  • Friction-free flow: The friction effect is negligible, and the viscous effect is neglected.
  • Fluid flows along streamlines: fluid elements flow along streamlines. The streamlines do not intersect each other.

Extended reading: Silicon Pressure Sensor

Extended reading: Pressure Sensor Applications-Featured Industry Applications

how to calculate flow rate in pipe?

The flow rate Q can be calculated using the following formula:

Q= A × v

Q is the flow rate, usually expressed in m³/s or L/min.
A is the cross-sectional area of the pipe and can be calculated using the formula π×(d/2)² (for circular pipes), where d is the diameter of the pipe.
v is the average flow velocity of the fluid in the pipe, usually in m/s.

So, to calculate the flow rate in a pipe, you need to know the diameter of the pipe and the velocity of the fluid.

how to calculate flow rate from pressure?

Calculating flow directly from pressure is more complicated because the relationship between them is affected by many factors. Such as the size of the pipe, the viscosity of the fluid and the roughness of the pipe. But under some specific conditions, the following formula can be used:

For laminar flow (slow flow rate and smooth fluid flow):

Q=(πd^4△P)/ (128*μ *L)

Q is flow.
d is the diameter of the pipe.
ΔP is the pressure difference across the pipe.
μ is the viscosity of the fluid.
L is the length of the pipe.

For turbulent flows (faster flows and unstable fluid flow), the relationships are more complex and require the use of more complex formulas or empirical curves.

In summary, calculating flow directly from pressure requires consideration of several factors. In practical applications, flow meters are often used to directly measure flow, or software and simulation tools are used to estimate it.

Flow Rate and Pressure Calculator

Our Converter Tools for Pressure and Flow

Tools for converting and calculating pressure values. Help users choose suitable pressure sensors and transmitters!

Absolute pressure-Gauge pressure ConverterPressure Unit ConverterLiquid Depth/Level to Hydrostatic Pressure Calculator
Differential Pressure CalculatorPressure Transducer 4-20ma Output CalculatorPressure to Liquid Level Calculator

Converters for conversion and calculation of flow. Or a calculation tool that requires flow measurement to obtain other measurement parameters. Help users choose the right flow sensor and transmitter!

DP Flow Meter Output CalculatorFlow Meter 4-20mA Current Output CalculatorFlow Velocity & Pipe Diameter to Volumetric Flow Rate Calculator
Mass Flow & Density to Volume Flow CalculatorMass Flow Rate Unit ConverterVolume Flow Rate Converter
Volume Flow & Density to Mass Flow CalculatorVolumetric Flow Rate & Pipe Diameter to Flow Speed Calculator

Featured Flow Meters

Extended Reading: Up to 800°C High Temperature Pressure Sensor

Learn more about pressure and flow rate relationship

Pressure drop also known as pressure loss, is a technical and economic indicator that indicates the amount of energy consumed by the device. It is expressed as the total pressure difference of the fluid at the inlet and outlet of the device. Essentially reflects the mechanical energy consumed by the fluid passing through the dust removal device (or another device). It is proportional to the power consumed by the ventilator.

Extended reading: wireless pressure transmitter working principle

Pressure drop includes pressure drop along the way and local pressure drop.

Pressure drop along the way: refers to the pressure loss caused by the viscosity of the liquid when the liquid flows in a straight pipe.

Local pressure drop: refers to the pressure loss caused by the liquid flowing through local resistances such as valve ports, elbows, and flow cross-section changes.

The cause of the local pressure drop: when the liquid flows through the local device, a dead water zone or vortex zone is formed. The liquid does not participate in the main flow in this area. It’s the constant swirling. Accelerate liquid friction or cause particle collisions. Produce local energy loss.

When the liquid flows through the local device, the magnitude, and direction of the flow velocity change drastically. The velocity distribution law on each section is also constantly changing. Cause additional friction and consume energy.

Extended Reading: How to Measure Volume of Liquid

For example. If a part of the flow channel is restricted, the downstream pressure will start to decrease from the restricted area. This is called pressur drop. Pressure drop is energy loss. Not only the downstream pressure will decrease, but the flow rate and velocity will also decrease.

Extended reading: how to calibrate a pressure transmitter

When pressure loss occurs on the production line, the flow of circulating cooling water will decrease. This can cause various quality and production problems.

To correct this problem, the ideal way is to remove the parts that cause pressure drop. However, in most cases, the pressure drop is handled by increasing the pressure generated by the circulating pump and/or increasing the power of the pump itself. This measure wastes energy and generates unnecessary costs.

The flowmeter is generally installed in the circulation pipeline. At this time, the flowmeter is actually equivalent to a resistance part in the circulation pipeline. The fluid will produce pressure drop when passing through the flowmeter, causing a certain amount of energy consumption.

The smaller the pressure drop the smaller the additional power required to transport the fluid in the pipeline. The lower the energy consumption is caused by the pressure drop, The lower the energy metering cost. On the contrary, the greater the energy consumption caused by the pressure drop. Energy The higher the measurement cost. Therefore, it is very important to choose the right flow meter.

Extended reading: Make Ultrasonic Open Channel Flow Meter Work for You

When the piping system is determined, the flow rate is related to the square root of the pressure difference. The greater the pressure difference, the greater the flow rate. If there is a regulating valve in the pipeline system (man-made pressure loss). That is, the effective pressure difference is reduced, and the flow rate is correspondingly smaller. The pipeline pressure loss value will also be smaller.

Extended Reading: Electronic Pressure Switch for Air Compressor

What Is Flush Diaphragm Pressure Sensor?

The measuring principle of the differential pressure flowmeter is based on the principle of mutual conversion of the mechanical energy of the fluid.

Extended reading: Orifice Plate Flow Meter

The fluid flowing in a horizontal pipe has dynamic pressure energy and static pressure energy (potential energy equal).
Under certain conditions, these two forms of energy can be converted to each other, but the sum of energy remains unchanged.

Take the volume flow formula as an example:
Q v = CεΑ/sqr(2ΔP/(1-β^4)/ρ1)

Among them:

  • C outflow coefficient;
  • ε Expansion coefficient
  • Α The cross-sectional area of ​​the throttle opening, M^2
  • ΔP Differential pressure output by throttling device, Pa;
  • β diameter ratio
  • ρ1 The density of the measured fluid at I-I, kg/m3;
  • Qv volume flow, m3/h

Extended Reading: Liquid pressure sensor

According to the compensation requirements, it is necessary to add temperature and pressure compensation. According to the calculation book, the calculation idea is based on the process parameters at 50 degrees. The flow rate at any temperature and pressure is calculated. In fact, the important thing is the conversion of density.

Calculated as follows:
Q = 0.004714187 d^2ε*@sqr(ΔP/ρ) Nm3/h 0C101.325kPa

That is the volume flow rate at 0 degrees of standard atmospheric pressure is required to be displayed on the screen.

According to the density formula:
ρ= PT50/(P50T)* ρ50

Among them: ρ, P, T represents values ​​at any temperature and pressure
ρ50, P50, T50 indicate the process reference point at a gauge pressure of 0.04MPa at 50 degrees

Combining these two formulas can be completed in the program.

Extended reading: Cryogenic Flow Meters | Liquid Nitrogen-Liquid Oxygen


There is a close relationship between pressure and flow rate. An increase in pressure will increase the flow rate. Changes in pressure, container materials, fluid properties and fluid flow forms will also directly affect the change in flow rate.

To be precise, the flow rate increases as the pressure difference increases.

If you cannot find an answer to your question in our Flow Rate and Pressure, you can always contact us and we will be with you shortly.

More Flow and Pressure Measurement Solutions

Extended reading: Best Price Ceramic Pressure Sensor

Sino-Inst offers over 50 flow meter for flow measurement. About 50% of these are differential pressure flow meters, 40% is the liquid flow sensor, and 20% are Ultrasonic Level Transmitter and mass flow meter.

A wide variety of flow meters options are available to you, such as free samples, paid samples.

Sino-Instrument is a globally recognized supplier and manufacturer of flow measurement instrumentation, located in China.

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Water Flow Measurement for Pipes and Open Channels

Water flow measurement is common in both industry and life. You may often hear about the use of electromagnetic flowmeters to measure wastewater. The clamp-on ultrasonic flowmeter measures large water pipes. The establishment of a new irrigation system requires monitoring of water flow. Even rivers and open channels need water flow detection. Use various water flow meters to detect flow and output 4-20mA or RS485 digital signals. Helps us effectively monitor and manage water flow.

Next, we will boldly analyze and sort out the method of Water flow measurement.

Water Flow Measurement

Water Flow Measurement can be simply divided into the following two situations: closed pipes and open channels.

Among them, pipeline water flow measurement is divided into full pipe and non-full pipe measurement. Open channel water flow measurement can be divided into regular channels and irregular rivers.

Extended Reading: LORA water meter

Water flow measurement in water pipes generally refers to measuring the water velocity or water flow in the pipe.

In closed pipes, water flow measurement can be divided into two situations: full pipe and non-full pipe.

Full Pipe measurement:

Full pipe measurement, as the name suggests, refers to the situation when the pipe is completely filled with water. At this time we usually use electromagnetic flowmeter or ultrasonic flowmeter for measurement.

The electromagnetic flowmeter uses the Faraday electromagnetic induction principle to accurately measure the water flow velocity and then calculate the flow rate.

The ultrasonic flow meter determines the flow rate by detecting the time difference in the propagation of ultrasonic waves in the fluid.

Partially full pipe measurement:

For non-full pipes, the situation is slightly more complicated. A partial pipe means that the water does not fill the entire pipe. In this case, we usually use a special electromagnetic flowmeter to measure it.

Further reading: Inline water flow meters

Open channel flow meters can be used in harsh environments. Such as urban water supply diversion channels, sewage treatment inflow and discharge channels, and corporate wastewater discharge.
Next, we will introduce to you the specific method of open channel flowmeter such as flow measurement.

And when our sight shifts from underground pipes to open channels on the ground, there are different methods for measuring water flow.

Regular drains:

In a regular channel, the shape and size of the flow are known. In this case we usually use a weir or Farrer flume to measure the flow. From the change in height of the water as it passes over these structures, we can calculate the amount of water flowing through.

Irregular river channels:

For irregular river channels, due to the complex and changeable shapes of the river bed and river banks, we generally use a current meter to directly measure the speed of the water flow and calculate the flow of the entire river channel based on the cross-sectional information of the river channel.

Extended reading: Make Ultrasonic Open Channel Flow Meter Work for You

Extended reading: non contact flow meter

Water Flow Measurement Methods

With the development of science and technology and production, many places need to measure the flow of different liquids under different conditions. For this reason, after research, a variety of flow meters have been developed. These methods can be summarized as:

  1. Container method. Including weight method, volume method.
  2. Throttling method. Including orifice plate, nozzle, venturi tube, venturi nozzle, etc.
  3. Weir flow method. Including right-angled triangle weir, rectangular weir, full-width weir and other methods.
  4. Differential pressure method. Including volute differential pressure, elbow differential pressure, runner differential pressure, draft tube differential pressure, etc.
  5. Flow meter method.
  6. Tracer method. Including concentration method, integral method, transit time method, etc.
  7. Water hammer method.
  8. Ultrasonic method.
  9. Metering method. Including electromagnetic flowmeter, turbine flowmeter, vortex flowmeter, etc.
  10. Other methods. Including laser flow measurement technology, Pitot tube method, etc.

Extended reading: Ultrasonic Flow Meters Types & Technical Guide

Types of Water Flow Meter

A water flow meter measures the amount of water flowing through a pipe. We have several kinds to choose from, depending on the application, maintenance needs, and budget.

Extended reading: 2 inch Water Flow Meter

There are four common water flow meter types:

Turbine (also called mechanical), Vortex, Ultrasonic, and Magnetic. We will tell you everything you need to know about them and help you choose one for your application.

The electromagnetic flowmeter can measure the speed of the water by using a simple magnetic field.

When water passes through a magnetic field, a voltage is generated. In this way, higher flow rates always generate more voltage when sent through the electromagnetic flowmeter. The electronic system connected to this meter will receive the voltage signal and convert it into volume flow.

Remember that the water needs ions to generate voltage, which means that the electromagnetic flowmeter cannot be used with pure water without pollutants.

Guess you like: Magnetic Flow Meters types and technical guide

Extended Reading: 3 inch (3″) Water Meter

Turbine flow meters easily become the most common flow meters around, mainly because these flow meters are more affordable than other types.

The mechanical flow meter measures the water flow through the rotation of the turbine, which uses a basic propeller, blade, or split flow design. The flow rate of water is equal to the speed of the blades.

If mechanical flow meters are to be used, they may become clogged if the water is dirty or more contaminated than expected.

Therefore, you probably should not use this kind of flowmeter to measure the flow of slurry. Since these flow meters can become clogged, they are more frequently maintained than other flow meters.

Know more about: Turbine type Flow Meter for Liquid & Gas technology

The vortex flowmeter is a unique flowmeter that measures the flow of water by using vortex flow.

When the fluid pushes over the obstacle, it will produce a vortex and form a vortex. The flowmeter is equipped with a sensor tab. As long as the vortex flows through the sensor tab, the tab will bend, which will produce a frequency output indicating the flow rate of the water.

If you decide to choose a multivariable vortex flowmeter, it can measure up to five different variables that are useful for your specific application.

These variables include mass flow, temperature, density, flow rate and pressure. These meters are especially suitable for large pipelines.

Extended reading: High Pressure Rotameter for Liquids/gas-Upto 25 Mpa

Ultrasonic flow meters are designed to use ultrasonic technology to measure the speed of water as it passes through the pipeline.

You should understand two basic types of ultrasonic flow meters, including runtime flow meters and clamp-on ultrasonic flow meters.

If you choose a run-time flow meter, send a standard ultrasonic signal downstream before sending another signal upstream. These two signals are then compared to determine the water flow rate. This is mostly a pipeline water flow meter. It is often used for household water.

For clamp-on ultrasonic flowmeters, can be placed outside the pipe and are designed to emit acoustic pulses through the pipe wall in order to receive the measured value. Since they can be installed outside the pipeline, they can be used for almost any application and can be used with larger pipelines.

Extended reading: Industrial VS Residential inline water flow meters

Rotameter is also called float flowmeter. Rotameter is composed of three units: float flow sensor part, displacement-angle conversion mechanism part, and information conversion processing part. It is a traditional variable area flow measurement device. When the flow rate changes, the float moves up and down in the vertical tapered tube. The circular flow area formed between the cone and the float changes. It is a volumetric flow meter that realizes flow measurement based on this principle.

Extended reading: Metal Tube Flow Meter-Variable Area Flow Meters Principle

Rotameter can measure water and gas. But you must explain the medium and flow range with the manufacturer when selecting the model. The method of calibration by the manufacturer is different. The completed flowmeter cannot be used mutually.

Extended reading: Liquid Bitumen/Asphalt Flow Meter

Read more about: Hydrostatic Submersible Level Transmitter-Straight Rod Insertion

There are several methods/flow meters that can be used to measure open channels:

Use a flow meter to directly measure the flow of the river. There are many types of flow meters, mainly including differential pressure, electromagnetic, launder, and weir flow meters. It can be selected and used according to the actual flow rate range and test accuracy requirements.

Extended Reading: Chilled Water Flow Meter

Put the river water into a container of known capacity. Measure the time it takes to fill the container. Repeat the measurement several times. Find the average value t(s). A method to calculate the amount of water.

This method is simple and easy to implement, and the measurement accuracy is high. It is suitable for rivers with small river flows. However, there should be a proper drop between the overflow outlet and the receiving water body or an error can be formed by the aqueduct.

Select a straight river section. Measure the area of ​​the cross-section of the water flow within a 2m interval of the river section. Find the area of ​​the average cross-section.
Put a buoy in the upper reaches of the river and measure the time it takes for the buoy to flow through a certain section (L). Repeat the measurement several times. Get the average of the required time (t), and then calculate the flow velocity (L/t). The flow can be calculated as follows:

In the formula, Q is the water flow, the unit is m^3/min. v is the average flow velocity of the water flow, and its value is generally 0.7L/t, and m/s.S is the average cross-sectional area of ​​the water flow, the unit is m^2.

Calculate the river flow by measuring the cross-sectional area of ​​the water flow, measuring the river water velocity with a flow meter.
During the measurement, the number of vertical and horizontal measurement points at the point must be determined according to the depth and width of the channel. The method is simple, but it is easily affected by water quality and difficult to achieve continuous measurement.

Understanding the relationship between Flow Rate and Pressure may help you calculate mass or volume flow.

Acoustic Doppler flow measurement is developed using the principle of Acoustic Doppler. It can simultaneously measure the cross-sectional shape, water depth, velocity, and flow of the river bed at one time, and is suitable for flow monitoring of large rivers.

The host and transducer of the flowmeter are installed in a waterproof container. All are immersed in water when working and are connected with a portable computer through a waterproof cable. The operation and control of the flowmeter are carried out on the portable computer.
From the initial blind zone above 1m, it is reduced to the so-called “zero blind zones”. The profile unit is reduced to the current 0.05~0.25m. It is possible to apply it on wide and shallow rivers.

Extended reading: Insertion Ultrasonic Water Flow Meter – Designed for Agricultural Irrigation, Garden Management

Read more about: 5 Types of Flowmeters | 2023 New Guide to Flowmeter Types 

Featured Water Flow Measurement Devices

Read more about: How to Measure River Water Level?


Flow is the volume of fluid that passes in a unit of time. In water resources, flow is often measured in units of cubic feet per second (cfs), cubic meters per second (cms), gallons per minute (gpm), or other various units.

Read more about: Flow Unit Conversion Table

Users can also choose unit of flow rate. For volume flow, L/s, L/min, L/h, m3/s, m3/min and m3/h are available; while for mass flow, kg/s、kg/m、kg/h、t/s、t/m、t/h can be selected from. It is up to the habits and application requirements to pick up a proper unit.

Extended reading: Liquid Bitumen/Asphalt Flow Meter

There are many ways to calculate flow.
For example, Using the Flow Rate Formula: Q​ = ​A​ × ​v​.
where ​Q​ is the flow rate, ​A​ is the cross-sectional area at a point in the path of the flow and ​v​ is the velocity of the liquid at that point.

Or, Flow Rate Calculation Using Pressure:

Extended reading: Orifice Plate Flow Meter

A water flow meter is an instrument that can measure the amount of water passing through a pipe. There are a variety of water flow meter technologies to choose from. It depends on the water measurement application, budget terms, and maintenance requirements. Each of these flowmeter types has novel process principles, overall use value and unique advantages in use.

The water flow meter can measure hot water, cold water, clean water, dirty water and mud.

Extended reading: Hot Water Flow Meters Improve Heating-Boiler System

To measure the flow of water in a river, you can use the following methods:

  • Choose a suitable measuring point: Find a relatively regular place in the river with smooth water flow for measurement.
  • Using a current meter: Deploy a current meter (such as an electromagnetic current meter or buoy) into the river to measure flow velocity at different depths and locations.
  • Calculate the cross-sectional area: measure the width and depth of the river, draw the flow cross-section, and calculate the cross-sectional area.
  • Integrating the data: Multiply the flow velocity by the cross-sectional area to get a value for flow, usually expressed in cubic meters per second (m³/s).
  • Multi-point measurements: To get a more accurate estimate of flow across an entire river channel, measurements may need to be taken at a number of different locations and then averaged.

For example, radar flow measurement is currently a commonly used method. It consists of a vertical pole, a horizontal arm, a chassis, a solar power supply system, a collection equipment, a radar flow meter, and a radar water level meter.

Choose a suitable position for the pole and cross arm on the shore. The length can be used to fix the sensor radar current meter and radar water level meter above the river surface, facing the water flow, and can monitor the river surface flow rate and real-time water level at the same time. The collection and transmission equipment RTU in the chassis is then used to receive and process the real-time data and then wirelessly transmit it to the remote platform. Time can be set for real-time viewing, threshold alarm, etc.

For mechanical flow meters, there is usually a rotating needle or a series of rollers to display the flow rate. Record the readings on all rollers, from left to right, which represent the total amount of water that has flowed through since installation.

For electronic flow meters, just read the value on the digital display directly. The electronic flow meters we supply from Sino-Inst can display instantaneous flow and cumulative flow.

Read more about: Flow Meter Selection Guide

More Liquid and Gas Flow measurement techniques

Sino-Inst offers over 30 water flow meter products for Water Flow Measurement. About 50% of these are differential pressure flow meters. 40% are water meters (like the Insertion Turbine Flow Meter), and 40% are water treatment (like the Annubar flow meter ).

A wide variety of water flow meter for Water Flow Measurement options are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of water flow meters, located in China.

The top supplying country is China (Mainland), which supply 100% of the water flow meter respectively.

Sino-Inst sells through a mature distribution network that reaches all 50 states and 30 countries worldwide. Water flow meter products for Water Flow Measurement are most popular in Domestic Market, Southeast Asia, and Mid East.

You can ensure product safety by selecting from certified suppliers, with ISO9001, ISO14001 certification.

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Industrial Helium Flow Meters

Helium is a noble gas. Helium is widely used due to its unique properties as a rare gas, such as in ultra-low temperature coolants, aeronautics, welding, leak testing, semiconductors and other application fields.

Sino-Inst offers 4 common helium flow meters. Vortex flowmeter, thermal gas flowmeter, precession vortex flowmeter and metal rotor flowmeter. Meets helium flow measurement for pipe sizes from DN10 to DN1000.

Helium flow meters

Thermal mass flow meter for helium gas flow measurement

Helium (He) is an inert gas that does not easily react with other elements and is widely used in many industrial applications. Therefore, helium flow measurement devices are very important.

Thermal gas mass flowmeter is a flowmeter that can directly measure the mass flow of helium gas. Not only is it not affected by temperature, it is also not affected by pressure. The user does not have to make corrections for pressure and temperature. And for pipes above DN65 size, plug-in installation can be selected. Effectively reduce measurement costs.

The thermal gas mass flow meter produced by Sino-Inst to measure helium has the following advantages:

  1. A true mass flow meter does not require temperature and pressure compensation for gas flow measurement, and the measurement is convenient and accurate. The mass flow rate or standard volume flow rate of the gas can be obtained.
  2. Wide range ratio, can measure gases with flow rates as high as 100Nm/s and as low as 0.5Nm/s. It can be used for gas leak detection.
  3. Good seismic resistance and long service life. The sensor has no moving parts and pressure sensing parts, and is not affected by vibration on measurement accuracy.
  4. Easy to install and maintain. If site conditions permit, non-stop installation and maintenance can be achieved. (Special customization required)
  5. Digital design. Overall digital circuit measurement, accurate measurement and easy maintenance.
  6. Adopt RS-485 communication or HART communication. Factory automation, integration, and optional wireless remote monitoring can be realized.
  7. The power supply is optional AC220V, DC24V or AC220V/DC24V dual power supply.
  8. Display content: standard voltage, instantaneous flow, cumulative total, standard flow rate, etc.;
  9. Display units: NL/m, NL/h, Nm3/m, Nm3/h, L/h, Kg/h, Kg/m, t/h, t/m, g/S;
Applications of Thermal Mass Flow Meter

Vortex flow meter for helium gas flow measurement

The vortex flowmeter is based on the Karman vortex principle. That is, when the fluid flows through an object without flow resistance placed in the flow channel, alternating vortices will be formed behind it. Suitable for various industrial gases.

This flow meter has the following advantages for measuring helium flow:

  • High accuracy and repeatability: For low-density gases such as helium, it can accurately detect the vortex frequency formed after flowing through the probe. This frequency is directly proportional to the flow rate, allowing for accurate measurement.
  • No need for temperature and pressure compensation: Since helium is a single-component gas, its physical properties have little impact on flow rate due to changes in temperature and pressure within a certain range. Vortex flowmeters can directly measure volume flow without the need for additional temperature or pressure compensation.
  • Wide flow range: Vortex flowmeter has a wide flow measurement range. Able to adapt to the variable flow requirements of helium in different industrial applications.
  • High temperature and high pressure resistance: Vortex flowmeter can work at higher temperatures and pressures. This makes it possible to measure helium flow in harsh industrial environments.

Therefore, vortex flowmeters are ideal for measuring helium flow. Whether in precision measurements in the laboratory or in large-scale applications in industrial production processes.

Precession Vortex Flow Meter for helium gas

The intelligent precession vortex flowmeter is a new type of gas flow meter. This flowmeter integrates flow, temperature and pressure detection functions. And can automatically compensate for temperature, pressure and compression factor. It is widely used in petroleum, chemical industry, electric power, metallurgy, urban gas supply and other industries to measure various gas flows.

Therefore, the advantages of using a precession vortex flowmeter to measure helium are obvious. Installing a precession vortex flowmeter eliminates the need to install pressure sensors and temperature sensors. This also saves costs and installation time.

Metal Rotameter for helium gas flow measurement

Metal rotor flowmeter is an area flow measurement instrument commonly used in industrial automation process control. It has small size and stable and reliable operation. Suitable for measuring liquids, gases, various flow rates and use in various environments.

The metal rotor flowmeter is only suitable for helium flow measurement in DN15~DN150 pipelines. But its measurement also has unique advantages:

  • Suitable for flow measurement of small diameter and low flow velocity media;
  • The requirements for the front and rear straight pipe sections are low; More about: Flow Meter Straight Length Requirements Guide;
  • The pointer indicates instantaneous flow, and the double-row LCD displays instantaneous flow and cumulative total (optional);
  • All-metal structure, suitable for high temperature, high pressure and highly corrosive media;
  • Can be used in flammable and explosive hazardous locations;
  • With data backup and power-off protection functions (LCD display type);
  • Reliable work, low maintenance and long life;
  • Wider range ratio 10:1;
  • Multi-parameter calibration, keyboard setting alarm (with alarm type);
  • Optional external power supply or built-in 3.6V lithium battery power supply;

More Gas Flow Measurement Soluitons

Helium is very inert and does not easily react chemically with other substances. It can be widely used in various industries. Additionally, helium has low density, low boiling point, and high thermal conductivity properties, making it a very valuable gas.

In applications in the welding and metallurgical industries, helium can be used as a welding shielding gas;
In applications in cryogenic engineering, helium gas is usually used as the working medium of closed cycle cryogenic refrigerators.
Helium also has many special industrial applications.

We, Sino-Inst, are a professional flow meter manufacturer. In addition to helium flow meters, we also produce steam flow meters, oxygen flow meters, hydrogen flow meters, argon flow meters, and various other liquid and solid powder flow meters.

If you need to measure helium flow or purchase a helium flow meter, you can contact our engineers for technical support at any time!

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6″ Flow Meters List | 6 Inch- DN150 Connection

6″ Flow meters are specially designed for DN150, which is 6 inch pipes. If you happen to need to detect the flow of 6″ pipes. Then you can refer to the content of our blog. Hope this helps you find suitable 6″ flow meters.

Overview: What is a 6″ Flow Meter?

We usually say 6″ Flow Meter, and some people may default to 6″ Water Flow Meter, or 6″ Water Meter. But this is not rigorous. There are many types of flow meters. They can be 6″ electromagnetic flow meters, 6 ” Turbine flowmeter, 6″ ultrasonic flowmeter, 6″ mass flowmeter, 6″ mass flowmeter, 6″ gear flowmeter, etc. Different types of flowmeters are suitable for different media and different working conditions. So, We need to select an appropriate flow meter based on the actual measurement conditions.

Sino-Inst is a manufacturer of flow meters. Based on our many years of service experience, we have compiled the following content. Hope this helps you choose the right 6″ Flow Meter. Let’s take a look.

If you are new to flow measurement, please follow our steps to get familiar with it step by step.
If you are experienced, then you can choose to look directly at the type of flow meter that interests you.

Here you will find all the 6 inch sizes we offer.

Featured 6 inch Flow Meters

How to choose 6” flow meter?

Before choosing a 6″ flow meter, we should first know what kind of medium you are measuring?

The simplest distinction: gas or liquid?

If it is gas: what gas is it? Is it corrosive?
If it’s liquid: What liquid is it? Is it conductive? Is it corrosive? Is the viscosity higher? Whether there are particles, etc.

Why should the distinction be so clear? For example: you want to measure the water flow in a DN150 pipe. For different types of water, we will recommend different flow meters. And their prices may vary a lot.

For example, measure the water in DN150 pipes. There are many types of water, including: pure water, clean water, municipal water, fresh water, fire water, chilled water, RO water, soft water, raw water, rainwater, geothermal water, thermal condensate water, seawater, drinking water, hard water, thermal water Water, sewage, acidic water, drinking water, river water, tap water, industrial sewage, boiler water, chlorinated water, borehole water, distilled water, wastewater containing suspended particles, purified water, mineral water, deionized water, etc.

If the choice is simple, then electromagnetic flowmeter is the first choice.
In addition to some non-conductive RO water, deionized water, DM water, pure water, deionized water, etc. If you want to measure the volume flow of RO water, pure water, and deionized water, we can choose a 6-inch turbine flowmeter or a vortex flowmeter.
Mass flow meters can measure all of the above water, whether it is pure water or dirty water or water containing suspended solids. But the price of Coriolis flow meter is not cheap.

Therefore, in the first step of choosing a 6” flow meter, you must clearly know what the medium is in your pipeline.

Of course. In addition to knowing what the medium is, you also need to know the conditions inside the pipeline, the most basic ones: pressure and temperature. This is all you need to know.

Now that you know what’s going on inside your pipe, you need to understand the different types of 6″ Flow Meters.

6 inch Flow Meters Types

Let’s look at it step by step. First, let’s look at the types of DN150 flow meters that can measure liquids. And their respective measurement advantages and measurement ranges.

6″ Electromagnetic Flowmeter-The most commonly used Water Flowmeter

Magnetic Flow Meters: Suitable for conductive liquids, these flow meters measure flow rate based on Faraday’s law of electromagnetic induction. They are ideal for applications with corrosive or abrasive fluids.

The parameter configuration of the 6-inch electromagnetic flowmeter is as follows:

  • Electromagnetic Flowmeter
  • DN150-6 inches
  • Lining: Polyurethane, Teflon, rubber, polyurethane (PU), PFA, etc. optional.
  • Flow sensor electrode material: 316L SUS, Hastelloy B, Hastelloy C, titanium, tantalum, tungsten carbide, platinum, etc. optional.
  • Power supply: 24V DC or 220V AC power supply or battery power supply;
  • Output: RS485 Modbus RTU; optional HART protocol, pulse output, current 4-20mA output or frequency output;
  • LCD displays instantaneous flow and cumulative total
  • Integrated flange connection: flange end connection, RF, 6”, ANSI 150LB, #300, 600LB, JIS 10K, PN16, PN25, PN40, etc.
  • Flow range: 30-600 m3/h, 132-2641 GPM.
  • Accuracy: 0.5%
  • Temperature resistance: 70℃
  • Pressure resistance: 16bar

6″ Tubrine Flowmeter

Turbine Flow Meters: These flow meters use a spinning turbine rotor to measure flow rate. The rotor’s rotation frequency is proportional to the fluid velocity, making them ideal for clean, low-viscosity fluids.

The conventional configuration of DN150 turbine flowmeter is as follows:

  • Liquid turbine flow meter
  • DN150
  • DC24V
  • Output two-wire system 4~20mA
  • LCD displays instantaneous flow and cumulative total
  • Body material: 304 stainless steel, optional 316 stainless steel
  • Impeller 2Cr13
  • DN150 flange connection
  • Flow range: 30~300m3/h
  • Accuracy 0.5%
  • Temperature resistance 120℃, high temperature and extremely low temperature parameters can be customized;
  • The pressure resistance is 6.3Mpa, and the high pressure can be customized to 25Mpa or 42Mpa;

6 inch coriolis mass flow meter

Coriolis Flow Meters: By measuring the mass flow rate directly, these flow meters provide highly accurate measurements for liquids, gases, and slurries. Their unique ability to measure mass flow and density makes them versatile and reliable.

The conventional configuration of DN150 Coriolis mass flow meter is as follows:

  • Coriolis mass flow meter
  • DN150,
  • Flow range: 0~360000kg/h
  • Temperature range: -100~200℃
  • Pressure range: 0~4.0MPa
  • Accuracy: 0.1%
  • Display: cumulative+instantaneous+density+temperature
  • Material: measuring tube 316L, shell SS304
  • Explosion-proof level: ExdibIICT6 Gb
  • Protection level: IP67
  • Output signal: 0-10KHz, 4-20mA
  • Communication method: RS485, MODBUS
  • Power supply: 24VDC or 220VAC, integrated
  • Flange standards: GB/T 9119-2010, ANSI 150#, JIS 5k, etc. optional.

6 inch ultrasonic flow meter

Ultrasonic Flow Meters: By measuring the transit time or Doppler shift of ultrasonic signals, these non-invasive flow meters can accurately measure liquid and gas flow rates without contacting the fluid.

The configuration of ultrasonic flowmeter is relatively flexible. You can choose handheld host, wall-mounted host, etc.
Sensors can be selected from external clamp type, plug-in type, pipe type, etc.

It can be configured flexibly as long as it meets your installation needs. You can even add a temperature sensor to become a heat measuring instrument. More about: New Products! Insertion Type Ultrasonic Flow Meter-Heat Meter–Mono/multi-Channel

6 inch Oval gear flow meter

Positive Displacement Flow Meters: These flow meters measure flow rate by capturing a fixed volume of fluid and counting the number of times the volume is filled and emptied. They are ideal for high-viscosity fluids and applications requiring high accuracy.

For media with different viscosity, the measuring range of DN150 Oval Gear Flow Meter is also different. for example:

  1. Viscosity: 0.6—2mPa.s, measuring range: 45—190 m³/h
  2. Viscosity: 2—200mPa.s, measuring range: 34—190 m³/h、
  3. Viscosity: 200—1000mPa.s, measuring range: 27-133 m³/h
  4. Viscosity: 1000-2000mPa.s, measuring range: 19-95 m³/h

Ok. The above are several liquid flow meters we commonly use. Next, let’s look at the gas flow meter.

6 inch vortex flowmeter

Vortex Flow Meters: By measuring the frequency of vortices shed from a bluff body, vortex flow meters can accurately measure the flow rate of liquids, gases, and steam. Their robust design and low maintenance make them popular in various industries.

Common configurations of 6″ vortex flowmeters are as follows:

  • Vortex flowmeter
  • DN150
  • DC24V
  • Output: two-wire system 4~20mA, pulse, etc. optional.
  • LCD displays instantaneous flow and cumulative total
  • Body material 304 stainless steel
  • 600# American standard flange connection
  • Flow range: liquid 40~350m³/h; gas 280~2240m³/h; steam 1.4~11t/h;
  • Accuracy 1.5%
  • Temperature resistance: 100℃, 250℃, 350℃;
  • Pressure and temperature compensation optional.

6 inch thermal mass flow meter

Thermal gas mass flowmeter is designed based on the principle of thermal diffusion. The instrument uses the constant temperature difference method to accurately measure gas. Widely used in the measurement of oxygen, nitrogen, hydrogen, chlorine, torch gas, blast furnace gas, biogas and other gases.

The general configuration of the 6 inch thermal mass flow meter is as follows:

  • Thermal gas mass flow meter
  • DN150
  • AC220V/DC24V dual power supply
  • Output 4~20mA with RS485 communication
  • LCD displays instantaneous flow and cumulative total
  • Body material 304 stainless steel
  • Flange connection
  • Flow range: 64~6400Nm3/h
  • Accuracy 1.5%
  • Temperature resistance 100℃, 220℃ optional
  • Pressure 1.6Mpa

Inline or Insertion

Of course, finally you need to consider the structure of the flow meter. Most of the flow meters we mentioned above can be either inline type or plug-in type. For example, the DN150 pipe for measuring urea solution can be a 6″ inline electromagnetic flowmeter or a 6″ plug-in electromagnetic flowmeter. The vortex flow meter can also be a 6″ insertion type vortex flow meter, and the thermal flow meter can be a 6″ insertion type thermal flow meter.

More Flow Measurement Solutions

We, Sino-Inst, are a professional flow meter manufacturer. The 6″ Flow Meters supplied by us are widely used in various industries in various countries.

Our 6″ Flow Meters meet different user measurement needs. Whether you need to measure wastewater, seawater, urea, ammonia, sulfuric acid and other liquids, or dry chlorine, wet chlorine, biogas, compressed air, hydrogen, nitrogen, etc. gases. We can select suitable 6″ Flow Meters for you based on your measurement parameters.

If you have any questions about purchasing 6″ Flow Meters, please feel free to contact our engineers for free consultation!

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What Is Vortex Flow Meter? and FAQs

What Is Vortex Flow Meter?

A vortex flow meter is an advanced instrument designed to measure the flow velocity of fluids, both liquids,steam and gases, within a conduit or pipeline. Drawing upon the principles of fluid dynamics, it capitalizes on the formation of vortex trails, often referred to as the ‘Von Kármán Effect.’ As the fluid passes a strategically placed bluff body inside the meter, vortices are shed alternately on either side. The frequency of these shedding vortices is directly proportional to the fluid’s velocity. By capturing this frequency with sophisticated sensors, the vortex flow meter translates it into a precise flow rate. Valued for its durability and minimal pressure drop, it is a preferred choice across various industrial applications.

Featured Vortex Flow Meters

How Does Vortex Flow Meter Work?

A non-streamlined vortex generating body (bluff body) is provided in the fluid. Then two rows of regular vortices are generated alternately from both sides of the vortex generator. This vortex is called a Karman vortex street. As shown below.

The vortex rows are arranged asymmetrically downstream of the vortex generator.
Suppose the frequency of vortex occurrence is f, the average velocity of the incoming flow of the measured medium is V, the width of the upstream surface of the vortex generating body is d, and the diameter of the surface body is D.
According to the Karman vortex street principle, there is the following relationship:


In the formula:
F – Karman vortex frequency generated on one side of the generating body
St-Strohal number (dimensionless number)
V-average flow velocity of fluid
d-width of vortex generator

It can be seen that the instantaneous flow rate can be calculated by measuring the Karman vortex separation frequency. Among them, Strohal number (St) is a dimensionless unknown number,

The figure below shows the relationship between Strohal number (St) and Reynolds number (Re).

In the straight part of St=0.17 in the curve table, the release frequency of the wandering vortex is proportional to the flow rate, which is the measurement range of the vortex flow sensor.

As long as the frequency f is detected, the flow rate of the fluid in the pipe can be obtained. The volume flow rate can be obtained from the flow rate V. The ratio of the measured pulse number to the volume is called the instrument constant (K). See formula (2)


In the formula:
K=instrument constant (1/m³).
N=Number of pulses
Q=Volume flow rate (m³)

Composition of vortex flowmeter

A vortex flowmeter is like a clever detective that figures out how fast a liquid or gas is moving in a pipe. Let’s break it down:

  • Bluff Body: This is a small, flat piece that sticks out in the pipe. When fluid (like water or gas) flows past it, it creates little swirls or whirlpools, called vortices.
  • Sensors: These are the meter’s “ears.” They listen to and count these swirls. More swirls mean the fluid is moving faster.
  • Transmitter: Think of this as the meter’s “brain.” It takes the count from the sensors and works out the flow rate, or how fast the fluid is moving.
  • Display: Just like a screen that shows the score in a video game, the meter has a display. It shows the flow rate so people can read it easily.

In many places, from factories to water plants, people rely on vortex flowmeters because they’re accurate and trustworthy. They help make sure everything runs smoothly and safely.

What Are Multivariable Vortex Flow Meters?

MultiVariable Vortex Meter is a product concept proposed by Rosemount.
The Rosemount™ 8800 MultiVariable Vortex Meter automatically adjusts for changes in density, making it easy to accurately measure mass and corrected volume in steam and liquid applications. No moving parts or need to install impulse lines means fewer process upsets and smoother operations for your plant.

Rosemount’s Multivariable Vortex Flow Meters certainly have their unique technical advantages. For our Sino-Inst vortex flowmeter, we provide integrated temperature and pressure compensation or split temperature and pressure compensation.

So you may ask what is temperature pressure compensation?

What is the temperature and pressure compensation of a vortex flowmeter?

Temperature and pressure compensation: Temperature and pressure compensation is the correction made by the influence of the measured object on the pressure and temperature measurement under a certain pressure and temperature. At Tongchang, we provide the most temperature and pressure compensation when measuring gas flow, which is to obtain the flow rate under standard conditions by performing temperature and pressure compensation on the gas flow under working conditions.

Flow meters for the following measurement situations require temperature or pressure compensation:

  1. When measuring gas, temperature and pressure need to be compensated at the same time. Gases are generally settled based on standard volume flow rates. Because the volume flow rate of the gas changes when the temperature or pressure changes, the flow rate will change.
  2. When measuring saturated steam, single temperature compensation or single pressure compensation is required. The density of saturated steam has a fixed corresponding relationship with temperature or pressure (saturated steam density table). Knowing any of these, the density of saturated steam can be determined.
  3. When measuring superheated steam, temperature and pressure need to be compensated at the same time. Steam is generally settled in terms of mass flow rate. Because either temperature or pressure changes, the density of the steam changes and the mass flow rate changes accordingly.
  4. When measuring liquids, pressure compensation is generally not required. Below 5MPa, generally only the influence of temperature is considered, and temperature compensation is required for accurate measurement. In general measurements, you do not need to use any compensation; when measuring some hydrocarbons (such as crude oil), simultaneous compensation of temperature and pressure is generally required.

What Are Insertion Vortex Flow Meters?

Insertion vortex flowmeters are mainly used for flow measurement of large-diameter gas, liquid, and steam media fluids in industrial pipelines in various industries. For large pipe diameters, inline installation costs can be high.
Insertion vortex flowmeters are installed by drilling a hole in the process pipe with connections. Then insert the probe into the hole through the connection on the meter. For insertion vortex flowmeters, the probe should be inserted into the part of the pipe where the flow rate is highest.

What are the Applications for Vortex Flow Meters?

  • Food & Beverage: Monitoring ingredient flow during product creation.
  • Factories: Monitoring liquid and gas usage in production.
  • Power Plants: Measuring steam flow for electricity generation.
  • Oil and Gas: Overseeing extraction and transportation processes.
  • Water Treatment: Managing water flow for purification.
  • Pharmaceuticals: Ensuring precise measurements for medicine production.
  • Chemical Industries: Overseeing chemical reactions and product development.
  • HVAC Systems: Regulating heating, ventilation, and air conditioning flows.
  • Pulp & Paper Mills: Managing liquid processes in paper production.
  • Agriculture: Supervising irrigation and water distribution for crops.

What Media Can Vortex Flow Meters Measure?

We all know that vortex flow meters can measure gas, steam, and liquid. Based on our many years of service experience at Sino-Inst, we have compiled some measurable media:

  • Water, Chilled or Hot
  • Ultra-pure Water
  • De-ionized Water
  • Glycol Mixtures
  • Solvents & Acids
  • Natural Gas
  • Steam (Saturated and Superheated)
  • Air and Compressed Air
  • Chemicals (Various Types)
  • Hydrocarbons (like oil)

This is just a small part, you are welcome to leave a comment to add more measurable media.

What are the Advantages of Vortex Flow Meters?

  • All-Rounder: Measures gases, liquids, and steam effectively.
  • Budget-Friendly Setup: The initial cost isn’t sky-high.
  • Low Maintenance: If the media is clean, it’s mostly fuss-free.
  • Trustworthy: They are reliable and give accurate readings.
  • Built to Last: No moving parts means less wear and a longer life.
  • Flexible Installation: Place it at any angle, just make sure the core part (bluff body) is submerged.
  • Unfazed: Temperature or pressure changes? It just shrugs them off.
  • No Extra Heating Needed: Unlike some meters, it doesn’t need external heat to function.
  • Efficient: Generally, it doesn’t cause much pressure loss.

What are the Disadvantages and Limitations of Vortex Flow Meters?

  • Picky with Thick Liquids: Not the best choice for super thick or sludgy media.
  • Stay Clean: Doesn’t like media that leaves a residue or forms crystals.
  • Might Need Filters: Sometimes, extra equipment like strainers are needed.
  • Precision Matters: Extremely high or low flow speeds? It might falter a bit.
  • Steady Flow Needed: Pulsating or jumpy flows aren’t its cup of tea.
  • Space Hungry: It often asks for a long straight pipe path for best results.
  • Not the Batching Type: If you’re into batching processes, it might not be the best fit.

What is the difference between vortex and mass flow meter?

Vortex flowmeters and mass flowmeters are both important flow measurement instruments. Mass flow meters have a unique point: they can measure density.
Other comparison details are as follows:

ParameterVortex Flow MeterMass Flow Meter
Suitable forLiquids, gases, steamAlmost all liquids & gases, including complex fluids
Not suitable forHigh viscosity media, slurriesVery few; possibly some specialized applications
AccuracyInline type: ±1.5%R,
Insert type: ±2.5%R,
Required upstream pipe (diameters)There are requirements for straight pipe sections. For example, there is a 15DN straight pipe section upstream and a 5DN straight pipe section downstream.The installation requirements are not high. There are no requirements for upstream and downstream straight pipe sections.
Relative costGenerally lowerTypically higher due to complexity
Effect of viscosityCan impact performance; not for high viscosityMinimal effect; can handle varying viscosities
Moving partsNoneMight have sensors & heaters but typically no moving parts
Pipe sizeDN15~`DN2000DN3~DN200

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Vortex Flow Meter Manufacturers

With a rich history and dedication to innovation, Sino-Inst has become a trusted name in the flow measurement industry. Over the years, our expertise in crafting state-of-the-art vortex flow meters has solidified our position as a leader in this domain.

Sino-Inst offers a versatile range of flow meter solutions, including both inline and insertion models. For those looking beyond traditional vortex meters, we proudly present our specialized solutions tailored for unique application requirements.

Ensuring reliability and precision, our products are a testament to our commitment to engineering excellence and customer satisfaction. To explore our diverse product range and delve deeper into the world of advanced flow measurement solutions, visit the Sino-Inst product page.

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Guide to Pulse Flow Meters: Must Know Before Shopping!

Pulse flow meters stand as a paragon of modern flow measurement technology. Pulse signals, often relayed to devices like PLCs as input data, help industries measure and manage flow with unparalleled precision. While many might be familiar with the traditional water meter or turbine flow transmitter, the evolution of flow measurement technology has introduced sophisticated devices such as the electromagnetic flow meters and dual pulse systems. The role of pulse signals, especially in devices like the turbine flowmeter, is crucial. It ensures the accurate translation of magnetic flow into actionable data, transforming how industries monitor and optimize their operations.

Featured Pulse Flow Meters

what is pulse output signal?

A pulse output signal is an integral facet of modern flow measurement. Essentially, it is a series of electronic pulses generated each time a specific volume of fluid, such as water, passes through a meter. Think of it as the flow meter’s heartbeat, where every pulse equates to a predetermined volume of fluid.

The mechanics behind this are quite fascinating. Within many flow meters, such as turbine flowmeters, the fluid’s movement causes an internal rotor to turn. As this rotor spins, it interacts with sensors—often magnetic ones. Each interaction results in the generation of an electronic pulse. The number of these pulses directly corresponds to the volume of fluid that has passed through the meter. This real-time pulsating data representation is invaluable as it grants accurate, instantaneous measurements, making data interpretation and integration seamless in various systems.

Pulse Output vs 4-20mA

When diving into the world of flow measurements and signal outputs, a frequent comparison arises between pulse output and the traditional 4-20mA signal.

The 4-20mA signal is a staple in analog devices, providing a continuous current signal that correlates to the measurement variable. On the flip side, pulse output offers discrete, distinct signals.

While both pulse output and 4-20mA signals have their unique strengths, the digital character of pulse outputs typically allows for more precise data. This is especially true in applications that demand rapid response or detailed flow analysis. In essence, while 4-20mA signals give a continuous overview, pulse outputs provide granular, moment-by-moment insights, leading to a richer understanding of flow dynamics.

Pulse Flow vs. Continuous Flow

In the world of flow measurement, two prominent types emerge: pulse flow and continuous flow. Understanding their distinctions is pivotal for industries aiming to optimize their fluid management processes.

Pulse Flow Meters:

Pulse flow meters, as the name suggests, measure flow using a pulsating technique. With every predefined volume of fluid that passes through, the meter emits an electronic pulse. This digital representation makes it ideal for applications requiring precision and rapid data collection.

Key Features of Pulse Flow Meters:

  • Real-time Data: These meters provide instantaneous measurements, giving an up-to-the-moment view of flow rates.
  • Digital Precision: As they operate based on discrete pulses, they can offer granular data, capturing even minor fluctuations in flow.
  • Versatility: Pulse flow meters can be integrated into various systems, making them suitable for diverse applications.

Continuous Flow Meters:

On the other hand, continuous flow meters offer a steady, uninterrupted measurement of fluid flow. Instead of discrete pulses, they provide a continuous analog signal, representing the flow rate over a period.

Key Features of Continuous Flow Meters:

  • Consistent Monitoring: These meters are excellent for applications where continuous monitoring is essential, providing a holistic view of flow dynamics.
  • Analog Output: They typically use signals like 4-20mA, offering a smooth data curve over time.
  • Broad Range: Continuous flow meters can capture a wide range of flow rates, making them versatile for varied applications.

In Conclusion:
Choosing between pulse and continuous flow meters boils down to the specific needs of an application. Pulse flow meters shine in scenarios demanding detailed, real-time data. In contrast, continuous flow meters are the go-to for holistic, round-the-clock monitoring. By understanding their core differences, industries can make informed decisions, ensuring optimal flow management.

Pulse Flow Meter Working Principle

The Core Principle:
At its essence, a pulse flow meter operates by translating the flow of fluid into electronic pulses. Think of these pulses as the meter’s heartbeat, with each beat or pulse representing a specific volume of fluid that has flowed through the meter.

How It Works:

  • Fluid Interaction: As fluid (be it water, oil, or any other liquid) passes through the meter, it interacts with a mechanism inside, often a rotor or a turbine.
  • Rotor Movement: This fluid movement causes the rotor to spin. The speed of this rotation correlates directly with the flow rate of the fluid.
  • Sensing the Rotation: Surrounding this rotor are sensors, usually of a magnetic nature. Each time the rotor completes a specific rotation or passes a point, it triggers these sensors.
  • Pulse Generation: Every trigger from the rotor to the sensor results in the creation of an electronic pulse. This is relayed as an output from the flow meter.
  • Data Interpretation: The number of pulses over time gives a precise measure of the volume of fluid that has passed through. The faster the fluid flow, the quicker the pulses are generated.

Why Pulse Signals Matter:
Pulse signals offer a clear advantage – digital precision. Unlike analog signals that provide a continuous representation, pulse signals give a moment-by-moment account of flow, making data interpretation straightforward and accurate.

Flow Meter Pulse Output to PLC: A Seamless Integration for Precision

In the landscape of industrial automation, the synergy between devices can be the linchpin of operational efficiency. A prime example of this is the integration of flow meters, specifically their pulse outputs, with Programmable Logic Controllers (PLCs). Let’s explore this integration and its significance.

In essence, when fluid passes through a flow meter, it results in the generation of electronic pulses. Each pulse represents a specific volume of the fluid, offering a digital snapshot of the flow rate.

PLCs serve as the brains behind many automated systems. They accept inputs from various devices, process this data based on programmed logic, and then generate outputs to control equipment or processes.

The Integration Process:

  • Signal Transmission: The flow meter generates pulse outputs based on fluid flow. These pulses are then transmitted as electrical signals to the PLC.
  • Data Interpretation: Upon receiving the signals, the PLC interprets the frequency of pulses to determine the flow rate. The higher the frequency, the greater the flow.
  • Actionable Outputs: Based on the interpreted data and the logic programmed into the PLC, decisions are made. This can range from adjusting valves, triggering alarms, or even integrating with broader systems for holistic process control.

Benefits of Integration:

  • Real-time Control: By continuously monitoring flow rates, PLCs can make instant adjustments, ensuring optimal operations.
  • Data Accuracy: The digital nature of pulse outputs ensures precision, leading to accurate and reliable PLC actions.
  • System Flexibility: The ability to program PLCs means that as system requirements change, adjustments can be made without altering the physical infrastructure.

The integration of flow meter pulse outputs with PLCs exemplifies the power of modern automation. This seamless synergy offers industries a reliable, flexible, and precise method to monitor and control fluid flow, driving efficiency and accuracy in operations. By understanding this integration, professionals can better harness the potential of their systems, leading to superior outcomes.

Applications of Pulse Flow Meters Across Industries

Pulse flow meters, with their unique ability to capture flow data through electronic pulses, have become an invaluable tool in various industries.

  1. Manufacturing:
    In the vast world of manufacturing, maintaining a consistent and accurate flow of liquids—whether it’s raw materials, coolants, or finished products—is paramount. Pulse flow meters offer real-time monitoring, allowing industries to maintain product quality, ensure safety, and optimize processes.
  2. Pharmaceuticals:
    Accuracy is non-negotiable in the pharmaceutical industry. When formulating medications, precise quantities of liquid ingredients need to be mixed. Pulse flow meters ensure that these formulations are consistent, safeguarding the efficacy and safety of medical products.
  3. Energy & Power Generation:
    In power plants, especially those relying on liquid fuels or coolants, monitoring flow is critical. Pulse flow meters track the rate of fuel consumption or coolant flow, enabling plants to optimize operations and reduce wastage.
  4. Agriculture:
    Modern agriculture heavily relies on irrigation systems. Pulse flow meters help farmers measure the flow of water, ensuring crops receive the right amount, neither too little nor too much.
  5. Water Treatment:
    In water treatment plants, accurate flow measurement is key for processes like filtration and chemical treatment. Pulse flow meters provide reliable data, ensuring water quality and efficient treatment.
  6. Food & Beverage:
    Whether it’s brewing beer or producing dairy products, the flow of liquids is at the core of the food and beverage industry. These meters ensure consistency in production, guaranteeing that every bottle, carton, or can meets quality standards.
  7. Chemical Processing:
    In chemical plants, reactions often require exact quantities of liquid reactants. Pulse flow meters allow for precision, ensuring desired outcomes and minimizing risks.

More Flow Measurement Solutions


A pulse flow meter operates by translating the flow of fluid into electronic pulses. As fluid flows through the meter, it typically causes a rotor or turbine inside to spin. As this rotor turns, it interacts with sensors, often of a magnetic nature. Each interaction results in the creation of an electronic pulse, with each pulse representing a specific volume of fluid that has passed through the meter.

To check a pulse flow meter:

Ensure the meter is properly installed and there’s no blockage in the flow path.
Check the pulse output wires and connections to ensure they’re correctly connected and free from damage.
Monitor the pulse output signals using a digital multimeter or a pulse counter. Compare the readings to the expected flow rate.
Periodically calibrate the flow meter to ensure its accuracy.

The “best” flow meter in terms of accuracy varies depending on the application and requirements. Pulse flow meters are highly accurate for many liquid applications. However, for specific use cases, other types like Coriolis, ultrasonic, or magnetic flow meters might offer higher precision. It’s essential to consult with a flow measurement expert or a trusted supplier like Sino-Inst to determine the most accurate flow meter for your specific needs.

The output voltage of a flow meter pulse typically depends on the design and model of the flow meter. Commonly, pulse outputs from flow meters can range from a low-level signal (less than 5V) to a higher level signal (up to 24V or more). It’s crucial to refer to the specific flow meter’s datasheet or consult with the manufacturer to determine the exact output voltage for a particular model.

From everyday products to specialized applications, pulse flow meters play a silent yet significant role. They stand as guardians of quality, efficiency, and safety across industries. Recognizing their applications allows professionals to better utilize them, driving innovation and precision in their respective sectors.

But flow measurement doesn’t stop at pulses. From crude oil flow measurement, ensuring the smooth operation of our energy sectors, to liquid level measurement, vital for reservoirs, tanks, and storage facilities. Moreover, the precise temperature measurement instruments play a crucial role, especially in industries where slight temperature variances can impact product quality or safety.

With a rich legacy in the field, Sino-Inst stands at the forefront of measurement technology. As an experienced manufacturer and supplier, our portfolio extends beyond pulse flow meters. Whether you need customized solutions or off-the-shelf instruments, our team is ready to assist, ensuring you have the right tools for your unique requirements.

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What Is Turbine Flow Meter? and FAQs

What Is Turbine Flow Meter?

A turbine flow meter capitalizes on the fluid’s mechanical energy, employing a precisely designed rotor that rotates within the flow path. This rotor’s rotational speed, intricately linked to the fluid’s velocity, offers an accurate measurement scale. Deployed across diverse industries, turbine flow meters stand as trusted instruments, delivering reliable measurements for not just liquids but also gases, underscoring their versatility and precision.

Featured Turbine Flow Meters

How Does a Turbine Flow Meter Work?

When the fluid flows through the sensor housing, since the blades of the impeller(rotor) are at a certain angle to the flow direction, the impulse of the fluid causes the blades to have a rotational torque. After overcoming the friction torque and fluid resistance, the blades rotate. After the torque is balanced, the rotational speed becomes stable.

Under certain conditions, the rotational speed is proportional to the flow rate.

Since the blade is magnetically permeable, it is in the magnetic field of the signal detector (composed of permanent magnet steel and a coil). The rotating blade cuts the magnetic lines of force, periodically changing the magnetic flux of the coil. This causes an electrical pulse signal to be induced at both ends of the coil. This signal is shaped by the amplifier to form a continuous rectangular pulse wave with a certain amplitude. It can be remotely transmitted to the display instrument to display the instantaneous flow rate or cumulative total volume of the fluid.

Within a certain flow range, the pulse frequency f is proportional to the instantaneous flow rate Q of the fluid flowing through the sensor. The flow equation is:


In the formula:
f—Pulse frequency [Hz]
K-sensor instrument coefficient [1/m3], given by the calibration sheet.
Q-instantaneous flow rate of fluid (under working condition) [m3/h]
3600-conversion factor

The instrument coefficient of each sensor is filled in the calibration certificate by the manufacturer. The K value is set into the matching instrument. The instantaneous flow and cumulative total can be displayed.

How Accurate are Turbine Flow Meters?

When it comes to flow measurement, accuracy is paramount. Among the various tools and instruments available, turbine flow meters are often the choice for many industry professionals. But how do they stack up in terms of accuracy? Let’s dive deep and shed light on this critical aspect.

The Basics of Turbine Flow Meter Accuracy

At its core, a turbine flow meter’s accuracy is determined by its ability to measure flow velocity reliably. Generally, these meters boast an accuracy range of ±0.5% to ±1% of reading for liquids and ±1% to ±2% for gases under optimal conditions.

Factors Influencing Accuracy

Several elements come into play that can influence the precision of turbine flow meters:

  • Fluid Properties: Variations in viscosity, especially in liquids, can impact rotor spin and subsequently, measurement accuracy.
  • Flow Profile: Turbulent or laminar flow profiles can influence the meter’s readings. Proper installation, away from bends and valves, can help maintain a stable flow profile.
  • Calibration: Calibration specific to the fluid being measured ensures that any discrepancies related to fluid properties are accounted for.

Turbine Flow Meter Types and Their Accuracy

Different designs and models cater to specific applications, each offering varying degrees of accuracy:

  • Liquid Turbine Flow Meters: Often achieve accuracy up to ±0.5% of reading.
  • Gas Turbine Flow Meters: Generally offer accuracy in the range of ±1% to ±2%.

What Does a Turbine Type Flow Meter Generate?

As we discussed earlier, the Turbine Flow Meter will generate pulses. The essence of a turbine-type flow meter lies in its ability to generate electrical pulses that correspond with fluid or gas flow rates. But what exactly is this output?

  1. Pulse Generation – The Heartbeat of the Meter
    The fundamental output of a turbine flow meter is a series of electrical pulses. As fluid or gas courses through the meter, it drives the turbine rotor, causing it to spin. Each rotation, or even a fraction of it, generates a distinct pulse.
  2. How Pulses Relate to Flow
    The rate at which these pulses are generated directly correlates with the flow rate of the fluid or gas. A higher flow rate will lead to a quicker rotor spin and, consequently, a higher pulse frequency. Conversely, a slower flow results in a reduced pulse frequency.
  3. Sensing Mechanisms – Translating Motion into Electrical Output
    Positioned adjacent to the rotor is a sensor, typically magnetic or optical. As the rotor blades spin, they disrupt the sensor’s field, creating an electrical pulse. The frequency of these pulses, hence, represents the fluid velocity and is the primary data output.
  4. Converting Pulses to Meaningful Data
    While the raw pulse frequency offers insights into flow rate, advanced electronic systems within the meter transform these pulses into actionable data. This can be displayed as volume per unit of time, totalized volume, or other relevant metrics, depending on the application.
  5. Additional Outputs
    Modern turbine flow meters often come equipped with capabilities beyond basic pulse generation. Some may offer analog outputs, like 4-20mA signals, which can be integrated into control systems. Others might feature digital outputs for more sophisticated monitoring or control setups.

What are the Advantages of Turbine Flow Meters?

Turbine flow meters, renowned for their precision and adaptability, bring a suite of benefits to industrial processes:

  • Cost-Effective: Generally, they are more economically priced when benchmarked against other advanced flow measurement technologies.
  • Swift Responsiveness: These meters exhibit an impressive response time, with repeatability rates as high as 0.05%, ensuring reliable measurements.
  • User-Friendly Installation and Upkeep: Their design facilitates straightforward installation and minimal maintenance, reducing downtime.
  • Adaptable Mounting: Universal mounting positions offer flexibility during setup, accommodating varied industrial requirements.
  • Direct Measurement: They provide direct volumetric flow measurements, eliminating the need for complex conversions.
  • Advanced Monitoring: Many models are compatible with cutting-edge monitoring electronics, enabling data analytics and real-time tracking.
  • Efficient Flow Dynamics: Their design results in minimal pressure drops, ensuring energy-efficient operations.
  • Low Flow Sensitivity: These meters can detect flow rates as low as 0.01 feet per second, ensuring accurate measurements even at reduced flow rates.
  • Wide range of use: Liquid turbine flowmeter can be made into an insertion type, suitable for large diameter measurements. Small diameter can be up to DN4.
  • Strong compatibility: For different media, there are 304 stainless steel, 316 stainless steel, PE materials, etc. available.
  • Customizable: Extremely low temperature (-196℃) and high temperature 180℃ can be customized. High pressure 16MPa, 25Mpa, 32Mpa, etc. can be customized.

What are the Disadvantages of Turbine Flow Meters?

While turbine flow meters offer numerous benefits, certain considerations can influence their suitability:

  • Wear due to Over-Ranging: Operating beyond the meter’s maximum flow rate can accelerate wear, affecting its lifespan.
  • Sensitivity to Contaminants: Certain models necessitate upstream filtering of ferrous particles to maintain accuracy. Moreover, magnetic particulates in fluids can hinder the output signals in some variants.
  • Full Pipe Requirement: For optimal accuracy, pipes must remain consistently full, as partial flows can skew readings.
  • Directional Limitations: By default, many models measure unidirectional flows. However, select advanced models can accommodate bi-directional flows.
  • Optimal Media Conditions: They are ideally employed for clean media with low viscosities. High particulate or viscous fluids can challenge accuracy.
  • Piping Considerations: To diminish flow turbulence, which can impact accuracy, they demand certain straight piping prerequisites upstream and downstream.

What are some applications for turbine flow meters?

Turbine flow meters, with their ability to provide rapid and accurate flow measurements, have found utility across a multitude of industries and applications. Below are some application introductions compiled based on our many years of service experience at Sino-Inst. Comments are welcome to add.

Oil and Gas Industry:

Oil Refineries: Turbine flow meters are pivotal in oil refineries for the precision measurement of crude oil and refined petroleum products.
Gas Distribution: They facilitate the measurement of gas flow rates, essential for billing and distribution.

Water Treatment Plants:

Monitoring and controlling water flow is crucial in these facilities, ensuring that adequate treatment processes are adhered to. Turbine flow meters serve this purpose by offering precise flow rate data.


In the domain of aviation fuel testing, turbine flow meters ensure that the correct volume of fuel is dispensed, keeping safety and efficiency at the forefront.


In drug manufacturing processes where specific volumes of liquids need to be transferred or mixed, these meters provide invaluable data, ensuring that the formulations are consistent and effective.

Dairy and Food Processing:

Turbine flow meters play a significant role in measuring the flow of milk, juices, and other liquid food products, ensuring quality control and correct product quantities.

Chemical Plants:

When it comes to transporting aggressive or corrosive liquids, turbine flow meters offer reliable readings, ensuring that processes remain within desired parameters.


For irrigation systems, accurately measuring water flow is crucial. These meters ensure that fields receive the optimal amount of water, promoting effective crop growth.

Hydraulic Testing:

Engineers rely on turbine flow meters for hydraulic system testing to ensure that systems operate under designated flow conditions.

Extremely low temperature conditions:

Low-temperature turbine flowmeters are also used for flow measurement of liquid nitrogen, liquid hydrogen, and liquid oxygen.

Are Turbine Flow Meters Suitable for Water?

Turbine flow meters shine in measuring clean, low-viscosity liquids, making them well-suited for water flow assessments. Their precision in water measurements is commendable, often surpassing other mechanical flow meters. However, for optimal performance, it’s crucial to ensure the water is free from large particulates that might obstruct the turbine, as well as devoid of magnetic particles and iron which could skew readings. When these conditions are met, the turbine flow meter remains a reliable choice for accurate water flow evaluations.

What Other Liquids Can Turbine Flow Meters Measure?

Beyond water, turbine flow meters have carved a niche in measuring a diverse range of liquids, proving their versatility in various industrial contexts. Their precision and adaptability make them a go-to choice for several liquid applications. Here are some prominent liquids that these meters effectively gauge:

  • Hydrocarbons: Fuels like diesel, petrol, and aviation fuel are commonly measured using turbine flow meters. Their consistent viscosity levels at operational temperatures make them an ideal fit.
  • Chemicals: From solvents like acetone and benzene to more viscous chemicals like glycol, turbine meters can handle a wide spectrum of chemical fluids, provided they’re free from impurities that could hinder measurement.
  • Alcohols: Ethanol, methanol, and other alcohols, often used in industrial processes or as fuels, can be accurately gauged with these meters.
  • Pharmaceutical Liquids: Turbine flow meters cater to the pharmaceutical sector by measuring liquids like saline solutions, syrups, or even certain liquid medications.
  • Food & Beverages: The food industry employs turbine flow meters for liquids like vegetable oils, fruit juices, and even dairy products, given the sanitary configurations available.
  • Lubricating Oils: The lubricant industry benefits from turbine flow meters, using them for measuring various grades of lubricating oils.
  • Cryogenic Liquids: With special configurations, these meters can even handle supercooled liquids, such as liquid nitrogen or liquid oxygen.

In conclusion, turbine flow meters are not just limited to water. Their broad spectrum of applicability across multiple industries, from petrochemicals to food processing, underlines their versatility and efficacy. However, always ensure compatibility and consider the specific requirements of each liquid for optimal measurement accuracy.

Can turbine flowmeter measure gas?

Turbine flow meters, while primarily designed for liquid measurements, are also adept at gauging the flow of gases. When tailored with appropriate design modifications and calibrated correctly, these meters can accurately measure various gases, from industrial to natural.

Takes into account the compressibility of the gas, the change in volume, temperature and pressure of the medium directly converts the flow under the working condition into the flow under the standard condition to ensure the accuracy of the measurement.

Our Sino-Inst gas turbine flowmeter is suitable for gas measurement in the fields of petroleum, chemical industry, aerospace, scientific research department, chemical industry and so on. It can be used for the measurement and measurement of natural gas, coal gas , propane, air, nitrogen and other gases. Used for trade measurement between users and process control between industrial production.

Are Turbine Flow Meters Inline or Insertion?

Turbine flow meters, given their versatility and adaptability, can be found in both inline and insertion models。Here’s a refined explanation of their distinct attributes:

Inline Turbine Flow Meters:
Popularity: These are the prevalent choice, especially when considering smaller pipeline sizes.
Design & Efficiency: Designed for a direct flow path, they offer an unobstructed measurement environment, ensuring maximum accuracy and efficiency.
Applications: Best suited for pipelines with smaller diameters, where precision is paramount.

Insertion Turbine Flow Meters:
Cost-Effectiveness: For those managing larger pipelines or higher flow velocities, insertion models are a more economical choice due to their design that doesn’t necessitate a complete flow body.
Installation: The process involves making a hole in the pipeline to insert the measuring probe. The electronics are then secured to the pipe via an integrated fitting.

What are the Straight Pipe Requirements for Turbine Flow Meters?

In order to eliminate the influence of liquid vortex and uneven cross-sectional flow velocity on the measurement, necessary straight sections or rectifiers should be installed at the inlet and outlet of the sensor.
Generally, the length of the straight pipe section in the upstream part (inlet) is required to be (15~20)D (D is the nominal diameter of the sensor).
The length of the downstream part (the straight pipe section at the outlet) is 5D, and the diameter of the straight pipe and the diameter of the sensor must be the same, otherwise it will cause measurement errors.

In addition, the length of the straight pipe section in the upstream part should be determined based on the status of the piping in front of the sensor. The general recommendations are as follows:

Do Turbine Flow Meters Have Digital Displays?

The turbine flowmeter can be configured with a local digital display. The LCD display can display instantaneous flow, accumulated flow, flow rate, etc.

Some customers only need signal output and do not need local display, so they will not configure a monitor.

Do Turbine Flow Meters Have Switches?

If you are purchasing a battery powered turbine flow meter. Then there is a switch for battery power.

If you are referring to the turbine flowmeter as a flow switch. So. Turbine flow meters sometimes offer integral or optional flow switch capabilities.

What is the K-Factor of turbine flow meter?

Definition of K-Factor:

The K-Factor of a turbine flow meter defines the number of pulses the meter will produce for a specific volume or mass of liquid passing through it. It’s typically expressed in pulses per gallon (PPG) or pulses per liter (PPL), depending on the unit of measure.

Significance in Flow Measurement:

By utilizing the K-Factor, one can accurately convert the number of pulses generated by the turbine flow meter into a quantifiable flow rate. This value is crucial when configuring flow meter transmitters or integrating the flow meter into process control systems.

Deriving the K-Factor:

To determine a turbine flow meter’s K-Factor, the meter is calibrated under controlled conditions using a fluid with a known density and viscosity. The number of pulses produced is then divided by the volume of fluid passed to derive the K-Factor.

Generally, after we produce the turbine flowmeter, we will calibrate it and standardize the corresponding K coefficient on the flowmeter.

Factors Influencing K-Factor:

  • Fluid Properties: Changes in fluid density and viscosity can influence the K-Factor.
  • Meter Wear: Over time, wear and tear on the turbine blades can alter the K-Factor.
  • Flow Profile: Turbulence or varying flow profiles can affect the accuracy of the established K-Factor.

How Much Do Turbine Flow Meters Cost?

How Much Do Turbine Flow Meters Cost?

Ok. This is probably what most readers want to know.

First of all, the price of turbine flow meters is not constant. Depending on the measurement parameters, there will be different configurations. Then the price of turbine flow meter will also be different.

Here, we provide you with a reference price:

Liquid turbine flow meter

Output two-wire system 4~20mA
LCD displays instantaneous flow and cumulative total
Body materialPE
Flange connection
Flow range 0.6~6m3/h
Accuracy 0.5%
Temperature resistance 65℃
Pressure resistance 1.0Mpa
ExdIICT6Gb explosion-proof
FOB Price USD 390.00/set

More Flow Measurement Solution

Liquid Turbine Flow Meters

Liquid Turbine Flow Meter is one of the most ideal flow meters for measuring liquids. Liquid Turbine Flow Meter is…

At Sino-Inst, we’re not just limited to turbine flow meters. We pride ourselves on our expansive range of instruments tailored for crude oil flow measurement, liquid level measurement, and temperature monitoring. With a rich heritage backed by experience, we’ve established ourselves as leading manufacturers and suppliers in the industry.

When it comes to reliability and accuracy, our instruments stand out. Our dedication to excellence stems from our profound expertise, ensuring that our clients receive products that not only meet but exceed their expectations. Looking for something unique? We offer customization to cater to your specific needs.

Contact us today and let our experts guide you to the perfect solution for your measurement challenges. Experience the Sino-Inst difference!

Flow Measurement
Industrial Flow Measurement Basics and Practice

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What Is a Thermal Mass Flow Meter?

What Is a Thermal Mass Flow Meter? A thermal mass flow meter is an instrument that measures the mass flow rate of gases directly, utilizing the principle of heat dispersion. It offers accurate and reliable readings without requiring external temperature or pressure compensation. Enter the thermal mass flow meter—a pivotal tool that has reshaped the way professionals gauge flow. This instrument not only simplifies measurement tasks but also offers unparalleled accuracy, underscoring its significance in modern industrial landscapes. Join us as we delve into its workings and uncover the essence of its rising prominence.

What are Thermal Flow Meters?

Thermal flow meters, known by several names like thermal meters, thermal mass flow meters, calorimetric flow meters, and thermal dispersion flow meters, all operate based on the same fundamental principle. Regardless of the terminology, they all refer to a device that uses the concept of heat dispersion for measuring flow rates.

A thermal mass flow meter is an instrument that measures the mass flow rate of gases or liquids directly, utilizing the principle of heat dispersion. It offers accurate and reliable readings without requiring external temperature or pressure compensation.

More About Thermal Mass Flow Meter Specification.

thermal mass flow meter working principle

Understanding the operation of a thermal mass flow meter boils down to grasping the idea of heat dispersion or, in more technical terms, the thermal dispersion principle.

The thermal gas mass flow meter is designed based on the principle of thermal diffusion. The instrument uses the constant temperature difference method to accurately measure gas. It has the advantages of small size, high degree of digitization, easy installation, and accurate measurement.

The sensor part of the thermal gas mass flow meter consists of two reference-level platinum resistance temperature sensors. When the meter is working, one sensor continuously measures the medium temperature T1. The other sensor self-heats to a temperature higher than the medium temperature T2, which is used for sensing The fluid flow rate is called a speed sensor.

The temperature ΔT=T2-T1, T2>T1. When fluid flows through the sensor, the temperature of T2 drops as the gas molecules collide with the sensor and take away the heat from T2. To keep △T constant, the supply current of T2 must be increased. The faster the gas flows, the more heat it takes away. There is a fixed functional relationship between the gas flow rate and the increased heat, which is the principle of constant temperature difference.

The larger the temperature difference or differential, the higher the gas flow, and vice versa. By continuously measuring this temperature difference, the thermal mass flow meter provides a real-time reading of the gas flow rate.

In essence, these meters transform the straightforward principle of heat dispersion into a reliable method for gas flow measurement, embodying both precision and technological brilliance.

Benefits of Thermal Mass Flow Meters Compared to Other Types

Direct Mass Measurement: Thermal mass flow meters excel in providing genuine mass flow readings for gases. Unlike other meters which measure volume first and then convert it to mass, these devices directly measure the mass flow. This means there’s no need for separate temperature and pressure compensation, ensuring both convenience and accuracy in gas flow measurement.

Wide Range of Measurement: These meters are versatile, capable of measuring gas flow speeds as high as 100Nm/s and as low as 0.5Nm/s. This broad range makes them particularly useful for applications like gas leak detection.

Robust and Durable: The sensors in these meters don’t have moving or pressure-sensitive parts, making them resistant to vibrations. This design ensures a long lifespan and consistent measurement accuracy, even in shaky conditions.

Easy Installation and Maintenance: One of the standout features is the ability to install and maintain these meters without halting production, provided the site conditions allow for it. This feature may require customization.

Digital Design: Embracing the digital age, these flow meters are designed with fully digital circuits. This not only ensures precise measurements but also simplifies maintenance tasks.

Advanced Communication: With RS-485 or HART communication options, these meters can seamlessly integrate into automated factories. There’s also the potential for remote wireless monitoring, with options like WeChat APP integration available.

Flexible Power Options: Users have the flexibility to choose their power source, with options including AC220V, DC24V, or a dual power source of AC220V/DC24V.

These features highlight the technological advancements and user-centric design of thermal mass flow meters, making them an optimal choice for diverse industrial applications.

What are Thermal Mass Flow Meters Used For?

Thermal mass flow meters, with their precise and consistent readings, have found their way into numerous industries and applications. Their value goes beyond just the technology; it’s about the real-world problems they solve and efficiencies they introduce.

Thermal mass flow meter applications in Industries:

  • Energy & Power Generation: Monitoring and controlling fuel gas flow in power plants ensures optimal combustion and energy efficiency.
  • Chemical & Petrochemical: From chemical reactions to gas distribution, the accurate measurement of gas flow is essential in these sectors.
  • Pharmaceuticals: Ensuring the right flow of gases in various drug manufacturing processes guarantees product consistency and safety.
  • Food & Beverage: Whether it’s the carbonation in your soft drink or the protective atmosphere in packaged foods, gas flow regulation is key.
  • Environmental Monitoring: They’re indispensable in monitoring greenhouse gas emissions or managing waste treatment plants.

Based on our many years of experience in gas measurement services. We have compiled and summarized the media suitable for thermal mass flow meters for your reference:

Gases Commonly Measured with Thermal Mass Flow Meters:

  • Oxygen (O2)
  • Nitrogen, (N2)
  • Carbon dioxide (CO2)
  • Hydrogen, (H2)
  • chlorine gas,
  • Argon (Ar)
  • Helium (He)
  • natural gas,
  • Liquefied gas,
  • fire energy,
  • compressed air
  • Multi-component gas measurement
  • biogas,
  • Methane (CH4)
  • Aeration and chlorine measurement in water treatment,
  • Gases,
  • Carbon dioxide gas flow rate during beer production,
  • Gas flow during semiconductor chip manufacturing process,
  • Gas flow measurement in solvent recovery systems
  • Refrigerators
  • blast furnace gas,
  • coke oven gas,
  • flue gas,
  • During the gas process, air,
  • Calcining furnace flue gas,
  • Combustion gas measurement in coal-fired boilers.
  • Smoke flow (speed) measurement of smoked meat (CEMS)
  • Primary air, secondary air,
  • Mine ventilation or exhaust system flow,
  • Gas flow (velocity) measurement in heating ventilation and air conditioning systems
  • And many more… (Comments are welcome to add)

If you are not sure whether you can choose a thermal mass flowmeter for your measurement conditions, please feel free to contact our Sino-Inst technical engineers!

thermal mass flow meter installation guidelines

Installation location and pipe requirements

① When installing the instrument, keep it away from elbows, obstacles, reducers, and valves to ensure a stable flow field. One side requires a longer upper straight pipe. The length of the front straight pipe is greater than 10D, and the length of the rear straight pipe is greater than 5D.
The figure below shows the length of straight pipe sections required for several situations often encountered on site.

② When the requirements for straight pipe sections cannot be met on site, gas rectifiers can be connected in series. In order to significantly reduce the requirements for straight pipe sections.

Installation of insertion flow meter with ball valve

① Open a 20~22mm hole in the pipe, and then weld the base to the hole with the base flow meter.
② After opening the ball valve, screw one end of the ball valve to the external thread welded to the base of the pipe (check the lock to prevent leakage), insert the probe rod and tighten the locking head (pay attention to the flow direction).
③When inserting the probe rod, pay attention to the insertion depth: insertion depth = A-B (1/4~1/2 of the inner diameter of the pipe).
④ If the medium contains moisture, oil or impurities, please refer to the figure below for installation (45 degrees below the pipe).

Installation of pipeline flow meter

Customers of pipeline flow meters do not need to select the insertion depth. They only need to select the flow rate corresponding to the diameter in the flow range table. When installing, just connect the flange (thread or clamp) of the flow meter to the pipe and fix it.

Selection Guide

Based on our many years of experience at Sino-Inst. We recommend that you consider the following measurement parameters when selecting a thermal mass flowmeter:

  1. Installation form: such as pipeline installation, plug-in installation, threaded installation, flange installation, etc.
  2. Pipe diameter (square pipe or round pipe)
  3. Conditions of the medium being measured
  4. Sensor material requirements
  5. Pressure and temperature inside the pipe
  6. What signal output is needed?
  7. Power supply requirements: Generally 24VDC, or 22VAC
  8. Explosion-proof requirements, etc.


Thermal mass flow meters are employed across a myriad of industries for the accurate measurement of gas flow rates. Key sectors include energy & power generation, chemical & petrochemical industries, pharmaceuticals, food & beverage, and environmental monitoring. Their precision and reliability make them indispensable for tasks that demand consistent and accurate gas flow regulation.

A thermal meter, or more specifically, a thermal mass flow meter, directly measures the mass flow rate of gases. It utilizes the principle of heat dispersion: as gas flows past a heated probe, it carries away heat. By measuring the temperature difference between this probe and a reference probe, the meter calculates the gas’s flow rate.

Thermal mass flow meters are known for their high accuracy, typically ranging from ±1.5% to ±2.5% of the flow rate reading, depending on the specific model and application conditions. Their ability to provide direct mass flow readings without the need for external temperature or pressure compensation contributes to their precision.

More Flow measurement technologies

Thermal mass flow meters, with their precision, durability, and wide applicability, have emerged as a front-runner in gas flow measurement. But the scope of modern measurement tools doesn’t end here. Advancements in technology have also paved the way for specialized instruments in other areas. For those involved in the oil industry, understanding crude oil flow measurement is crucial. Likewise, ensuring accuracy in liquid level measurement and temperature measurement can make all the difference in various applications, ensuring safety, efficiency, and product quality.

At Sino-Inst, our journey extends beyond just offering products. With a rich tapestry of experience, we stand as a leading manufacturer and supplier in the instrumentation arena. Whether you’re seeking standard instruments or looking for customized solutions tailored to your unique requirements, our team is here to assist.

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