Industrial Grease Flow meters are different from grease guns or grease meters. Industrial Grease Flow meters need to deal with more complex conditions. The pipe diameter can range from DN10 to DN200, or even larger. So how to choose the applicable Industrial Grease Flow meters? Let’s analyze it together.

Characteristics of industrial grease

What are the types of industrial grease?

Industrial greases mainly include hydraulic oil, gear oil, turbine oil, compressor oil, refrigeration oil, transformer oil, vacuum pump oil, bearing oil, metal processing oil (liquid), anti-rust grease, cylinder oil, heat treatment oil, and heat transfer oil.

Extended reading: High Temperature Flow Meter

In addition, there are greases with lubricating oil as base oil and thickening agent. The users of industrial lubricants are companies from all walks of life, and they use many varieties and large amounts.

The basic performance and main selection principle of industrial grease is viscosity. GB/T3141-94 is the ISO viscosity classification of industrial liquid lubricants, which is equivalent to the international standard ISO3448-1992 “Industrial Liquid Lubricants-ISO Viscosity Classification”.

So, when we choose an industrial grease flow meter, we first need to consider the viscosity of the grease. Then consider the flow range and temperature. And other special requirements of users.

Our commonly used industrial grease flow meters are oval gear flow meters, turbine flow meters, and gear flow meters. There is also a mass flow meter. Next, let’s discuss separately.

• Oval Gear
• Turbine
• Gear
• Mass

Grease Flow Meters-Oval Gear

Oval gear flowmeter is a volumetric meter for continuous or intermittent measurement and control of liquid flow in a pipeline.

Oval gear flowmeter, also known as positive displacement flowmeter. A positive displacement flowmeter as a mechanical flow meter is a common type of Volumetric Flow Meter. It can measure the volume flow of high viscosity and corrosive fluids.

• Volumetric Flow Meters
• High measurement accuracy;
• The installation pipeline conditions have no influence on the measurement accuracy;
• Can be used for high-viscosity liquids;
• Wide range;
• The direct-reading meter can directly obtain the cumulative and total amount without external energy.
• Clear and clear, easy to operate.

Therefore, we recommend that when the grease viscosity is high, you can first consider using an oval gear flowmeter.
Viscosity: 0.6—2mPa.s—200mPa.s—1000mPa.s-2000mPa.s.
Temperature: -20~+200℃

Extended reading: Sanitary Positive Displacement Flow Meter

Grease Flow Meters-Turbine

Turbine flow meters are velocity flow meters, also called impeller flow meters. Can be used to measure the instantaneous flow and cumulative flow of liquids and gases.

Turbine flowmeters are widely used in flow measurement: petroleum, organic liquids, inorganic liquids, liquefied gas, natural gas, coal gas, and cryogenic fluids. Turbine flowmeter signals can be divided into pulse signals or current signals (4-20mA). It is suitable for use with secondary display, PLC, DCS, and other computer control systems.

Therefore, when measuring low-viscosity oils, such as diesel, edible oil, etc., we recommend that turbine flowmeters be considered first.

Extended reading: What Is Hydraulic Flow Meter?

Grease Flow Meters-Gear

Gear flow meter is a micro digital positive displacement flow meter. Can measure very small flow rates and quantify small volumes of liquid. High and low-temperature resistance (-196℃-200℃).

The Gear flow meter for Microflow is made of stainless steel and is used for precise continuous or intermittent measurement of the flow or instantaneous flow of liquid. It is especially suitable for the flow measurement of heavy oil, polyvinyl alcohol, grease, and other high-viscosity media. It can measure the viscosity of Fluid up to 10000Pa.s.

• High pressure resistance (1.0-45MPa)
• High and low temperature resistance (-196℃-200℃)
• Can measure various viscous media
• High precision and repeatability
• Pulse output/analog output optional
• Wide range ratio (1:100)
• Wide measuring range
• Strong anti-corrosion and anti-fouling ability (acid and alkali)

Therefore, it is recommended to use Gear flow meters, when you need to measure grease in the following situations:High viscosity, low flow rate;Ultra-high temperatureUltra-low temperature;Small caliber;high pressure.

Extended Reading: Types Of Crude Oil Flow Meters

Grease Flow Meters-Mass

Mass flow meter directly measures the mass flow of the medium passing through the flow meter. It can also measure the density, temperature, and viscosity of the medium

Mass flow meter is a flow measuring instrument that measures the mass flow in the pipeline. The volume of a fluid is a function of fluid temperature and pressure and is a dependent variable. The quality of a fluid is a quantity that does not change with time, space temperature, and pressure. More about: What Is Mass Flow Rate?

The mass flow meter has high accuracy. But the price is expensive. Therefore, when you need high-precision measurement, you can choose to use a mass flow meter.

Extended reading: Fuel Flow Meter for Boat-Selection & Application

Tool: Volumetric Flow Rate & Pipe Diameter to Flow Speed Calculator

Find the most appropriate industrial grease flow meter from Sino-Inst for a variety of engineering and industrial purposes. Suitable for various fluids with different pressures and volumes. The choice of these depends on whether the volumetric or mass flow rate is to be measured. Grease flow meters offered on the site have wide minimum and maximum pressure ranges, which is considered to be a desirable quality as they can be used for a wider variety of fluids. These grease flow meters are highly accurate.

Explore Oil and Gas Flow Meters

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Updated Apr 9, 2026 — Reviewed by Sino-Inst Engineering Team

The K-factor of a flow meter is the number of pulses the meter generates per unit volume of fluid. It is a calibration constant — determined at the factory or in the field — that converts raw pulse counts into an actual flow volume. Every pulse-output flow meter has a K-factor. Get it wrong, and your flow readings will be off by a fixed percentage regardless of flow rate. This guide explains what K-factor means, how to calculate it, and how to handle multi-point calibration for better accuracy.

Contents

• What Is K-Factor in a Flow Meter
• K-Factor Formula and Units
• K-Factor for Turbine Flow Meters
• K-Factor for Vortex Flow Meters
• Multi-Point K-Factor Calibration
• Calculation Examples
• Common Mistakes with K-Factor Settings
• Featured Flow Meters
• Frequently Asked Questions

What Is K-Factor in a Flow Meter

K-factor is the ratio of pulse output to volume passed through the meter. If a turbine flow meter generates 100 pulses for every liter of water, its K-factor is 100 pulses/liter. The flow computer or totalizer uses this number to convert accumulated pulses into volume.

K-factor is determined during calibration by passing a known volume of fluid through the meter at a controlled flow rate and counting the pulses generated. A well-calibrated meter will have a K-factor that stays relatively constant across its operating range. No meter is perfect — the K-factor typically varies by 0.5–2% across the meter’s turndown range, which is why some applications require multi-point calibration.

K-factor is specific to each individual meter, not just the meter model. Two turbine meters of the same model and size will have slightly different K-factors due to manufacturing tolerances. Always use the K-factor from the calibration certificate shipped with your specific meter.

K-Factor Formula and Units

The basic formula:

K = N / V

Where K is the K-factor (pulses per unit volume), N is the total number of pulses counted, and V is the total volume of fluid that passed through. Common units include pulses/liter, pulses/gallon, or pulses/m³.

To calculate instantaneous flow rate from frequency:

Q = f / K

Where Q is volumetric flow rate, f is pulse frequency (Hz, i.e., pulses per second), and K is the K-factor in pulses per unit volume. If K = 450 pulses/liter and the meter outputs 75 Hz, then Q = 75/450 = 0.167 liters/second = 10 L/min.

K-Factor for Turbine Flow Meters

Turbine flow meters spin a rotor in the fluid stream. Each rotation passes a blade past a magnetic pickup, generating one pulse per blade. A meter with a 6-blade rotor spinning at 500 RPM produces 3000 pulses per minute (50 Hz). The K-factor ties this pulse rate to the actual volume flowing through.

For liquid turbine meters, K-factor typically ranges from 50 to 2500 pulses/liter depending on meter size. Smaller meters have higher K-factors (more pulses per liter) because the rotor makes more revolutions per unit volume. A DN15 (½”) turbine meter might have K = 2200 pulses/liter. A DN100 (4″) meter might have K = 55 pulses/liter.

Turbine meter K-factor is affected by fluid viscosity. As viscosity increases, bearing friction becomes a larger fraction of the driving torque, and the rotor under-reads. Most turbine meters are calibrated on water. If you use one on a higher-viscosity fluid (glycol, light oil), the K-factor will shift and you need a viscosity correction curve from the manufacturer.

K-Factor for Vortex Flow Meters

Vortex flow meters work on the Kármán vortex street principle. A bluff body placed in the flow sheds vortices alternately from each side. The shedding frequency is proportional to flow velocity, related by the Strouhal number (St ≈ 0.27 for cylindrical bluff bodies in the relevant Reynolds number range).

The relationship: f = St × v / d, where f is vortex shedding frequency, St is the Strouhal number, v is flow velocity, and d is the bluff body width.

Unlike turbine meters, vortex meters have no moving parts. Their K-factor is primarily determined by the geometry of the bluff body and the pipe diameter. This makes the K-factor highly stable over time — it does not degrade with bearing wear. Vortex meter K-factor is also less affected by fluid viscosity and density, making it a good choice for flow measurement across different fluid conditions.

Multi-Point K-Factor Calibration

A single K-factor assumes linearity — that the pulses-per-volume ratio is the same at all flow rates. In practice, most meters have some non-linearity. A turbine meter might read 0.3% high at low flow and 0.2% low at high flow.

Multi-point calibration measures K-factor at 5–10 flow rates across the operating range. The flow computer stores these points and interpolates between them. This can reduce measurement uncertainty from ±1% down to ±0.15% or better.

Typical calibration points for a turbine meter: 10%, 20%, 30%, 50%, 70%, 100% of maximum flow. Each point is run at steady-state for enough time to accumulate at least 10,000 pulses. The calibration certificate will list K-factor values at each point, along with the deviation from the mean K-factor.

For custody-transfer applications (oil & gas, chemical billing), multi-point calibration is mandatory. The flow meter calibration process must follow ISO 4185 or API MPMS Chapter 4 procedures. Recalibration intervals depend on the application — typically every 1–3 years for custody transfer.

Calculation Examples

Example 1: Single K-Factor

A DN25 turbine flow meter has K = 1850 pulses/liter. Over 8 hours, the flow computer records 3,330,000 pulses. What is the total volume?

V = N / K = 3,330,000 / 1850 = 1800 liters (1.8 m³). Average flow rate = 1800 / 8 = 225 L/hr = 3.75 L/min.

Example 2: Frequency to Flow Rate

A vortex meter has K = 12.8 pulses/liter and currently outputs a frequency of 64 Hz. What is the instantaneous flow rate?

Q = f / K = 64 / 12.8 = 5.0 liters/second = 300 L/min = 18 m³/hr.

Example 3: Determining K-Factor from Calibration

During a gravimetric calibration, 500 kg of water (density 998 kg/m³) is passed through a meter, and 278,500 pulses are counted. K = 278,500 / (500/998) = 278,500 / 0.501 = 556 pulses/liter.

Common Mistakes with K-Factor Settings

Using the wrong units. K-factor can be expressed in pulses/liter, pulses/gallon, or pulses/m³. If the calibration certificate says 450 pulses/liter but you enter 450 into a flow computer configured for pulses/gallon, your readings will be off by a factor of 3.785. Always confirm the units match.

Using a generic K-factor. Some installers use the “typical” K-factor from the product datasheet rather than the individual calibration certificate. This can introduce 1–2% additional error right from day one.

Not recalibrating after process changes. If you switch from water to a 30% glycol solution, the viscosity change will shift the K-factor on a turbine meter. The same applies to significant temperature changes that alter fluid properties.

Ignoring the minimum flow rate. Below the manufacturer’s minimum flow rate, K-factor drops sharply. The rotor or vortex shedding becomes erratic. Readings below minimum flow are unreliable regardless of K-factor setting.

Featured Flow Meters

Sino-Inst offers pulse-output flow meters with factory-calibrated K-factors and optional multi-point calibration certificates.

Frequently Asked Questions

What is a typical K-factor for a 1-inch turbine flow meter?

For a DN25 (1″) liquid turbine meter measuring water, K-factor is typically between 1500 and 2500 pulses/liter. The exact value depends on the manufacturer and the specific meter. Always use the K-factor from your individual meter’s calibration certificate.

Does K-factor change with temperature?

Indirectly. Temperature changes affect fluid viscosity and density. For turbine meters, higher viscosity (caused by lower temperature in most liquids) increases bearing drag and shifts the K-factor. Vortex meters are less affected because they have no moving parts. For high-accuracy applications, apply a temperature correction to the K-factor or use a multi-point calibration at the operating temperature.

How often should I recalibrate the K-factor?

For custody-transfer applications: every 1–3 years per API or ISO standards. For general process monitoring: every 3–5 years or when you suspect a shift. Turbine meters with bearings should be calibrated more frequently than vortex meters. If you notice a sudden change in K-factor, inspect the meter for damage, debris, or bearing wear.

What is the K-factor for an electromagnetic flow meter?

Mag meters also have a K-factor when configured with pulse output. However, since mag meters are inherently linear across their operating range, a single K-factor provides excellent accuracy. Typical values range from 1 to 10,000 pulses/liter depending on the configured scaling. The K-factor for a mag meter is set during commissioning and is very stable over time.

Can I use K-factor with 4-20mA output flow meters?

K-factor applies only to pulse outputs. For 4-20mA analog outputs, the equivalent concept is the span setting: 4 mA = zero flow, 20 mA = full-scale flow rate. Some flow computers accept both pulse and analog inputs and can calculate totalized volume from either signal, but the K-factor setting is only used for the pulse input.

What happens if I enter the wrong K-factor?

Your flow readings will have a fixed percentage error at all flow rates. If the true K-factor is 1000 pulses/liter but you entered 900, every reading will be 11.1% too high (the computer thinks each pulse represents a larger volume than it actually does). This error is constant and proportional — it does not vary with flow rate.

Need a flow meter with a factory-calibrated K-factor for your specific application? Contact our engineers for sizing assistance, multi-point calibration options, and pricing.

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Ultrasonic flow detectors types

Ultrasonic flow detectors can be divided into external paste type, insertion type, and pipe section type according to the installation method.

A) Clamp-on type

External paste type ultrasonic flowmeter is produced earlier, the user is more familiar with and more widely used ultrasonic flowmeter. Installation of the transducer without pipeline disconnection. That is posted that use, it fully embodies the ultrasonic flowmeter installation is simple, easy to use characteristics.

Extended reading: Portable ultrasonic flow meter for water

B）Pipe section type

Certain pipelines due to material sparse, poor sound conduction, rust and corrosion is serious. Lining and pipeline space with gaps and other reasons. Resulting in serious ultrasonic signal attenuation. Ultrasonic flowmeter with external paste type can not be measured normally. Generated the pipe segment ultrasonic flowmeter.

Pipe segment ultrasonic flowmeter to the converter and measuring tube composition as a whole, to solve the external paste flowmeter measurement in a problem. Measurement accuracy is also higher than other ultrasonic flowmeter. But at the same time also sacrificed the advantages of the external paste type ultrasonic flowmeter non-flow installation. Requires the installation of the transducer to cut the pipe.

Extended Reading: Inline Ultrasonic Flow Meter

C) Insertion type

Insertion type ultrasonic flowmeter in between the above two. Installation can be non-stop flow, the use of special tools have water pipes on the hole, the transducer into the pipe, complete the installation. Transducer pipeline, its signal emission, receiving only the measured medium. Its measurement is not limited by the pipe quality and pipe lining materials.

TM series standard clamp-on Ultrasonic flow detectors

HT series high temperature clamp-on ultrasonic flowmeter sensor

Other commonly used ultrasonic flow detectors:

What Does an Ultrasonic Doppler Flow Detector Measure?

From the ultrasonic measurement principle, the time difference method is suitable for measuring pure and less impurity liquids. Such as tap water, river seawater, sewage treatment plant effluent, etc. The Doppler method is suitable for measuring liquids and slurries with a high impurity content. Such as urban drainage, mud, pulp and so on.

Judging from the company’s years of practical experience, the two measurement methods are relatively vague for the quantitative indicators of the impurity content of the measured medium. The main reason is that there is currently no effective instrumentation for measuring the impurity content of liquids.

Doppler ultrasonic flowmeter flow rate measurement is based on the Doppler effect. The probe emits a beam of ultrasonic waves obliquely upward. Ultrasound propagates in fluids. The fluid will contain impurities such as bubbles or particles (it can be considered that the impurities in the fluid are at the same speed as the water flow).

When the ultrasonic wave contacts the impurities in the fluid, the reflected ultrasonic wave will produce a Doppler frequency shift Δf. The Doppler shift Δf is proportional to the flow velocity. The flow velocity of the fluid can be measured by measuring the Doppler frequency shift Δf.

The Dopp ultrasonic flowmeter uses the velocity area method to measure the flow. The flow velocity V is measured using an ultrasonic flow velocity sensor. Use a pressure water level gauge to measure the water level H. The channel parameters set in the controller in advance. The controller can use the water level to automatically convert the flow area S. The formula for the flow rate of the fluid is:

Q= V×S

Wherein V- – – -flow velocity S- – – -flow area Q- – -instantaneous flow

Since the velocity area method is used to measure the flow, it can be applied to any shape of the section.

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Sino-Inst, Manufacturer for Ultrasonic flow detectors. It can measure a single sound-conducting liquid medium of DN 15—150mm. It can measure even liquids such as water, seawater, oil, and slurry.

Sino-Inst’s Ultrasonic flow detectors, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, the US, and other countries.

Agricultural irrigation water system

It consists of irrigation canal head project, water transmission and distribution project and field irrigation project.

①Irrigation canal head project has reservoirs, pumping stations, dammed diversion projects, damless diversion projects, wells and other forms. Used to draw irrigation water at the right time and in the right amount.

② water transmission, water distribution projects include channels and canal buildings. Its task is to safely transport and reasonably distribute the water introduced at the head of the canal to all parts of the irrigation area. According to its function and scale, the general fixed channel is divided into dry, branch, bucket, agricultural four levels. Depending on the size of the irrigation area and the terrain, the number of levels of channels can be increased or decreased appropriately. Drainage buildings include diversion buildings, water measuring buildings, restraint buildings, articulation buildings, cross buildings, flood drainage buildings, drainage buildings, etc.

③ Field irrigation project refers to the temporary furrows, water transmission monopoly ditches and field irrigation ditches below the agricultural canals, border fields, and temporary water distribution and water measurement buildings. Used to irrigate the farmland. To meet the needs of normal crop growth or soil improvement.

Extended reading: Industrial VS Residential inline water flow meters

Irrigation flow meters for sale

river flow measurement instruments

The methods of river flow measurement are as follows:

1.Flowmeter method
The flow of the river is measured directly using a flow meter.
There are many types of flowmeters, mainly including differential pressure, electromagnetic, trough and weir flowmeters.
It can be selected and used according to the flow range of the actual flow and the test accuracy requirements.

2.Volume method
Pour river water into a container of known capacity and measure the time it takes to fill the container. Repeat the measurement several times. A method of calculating the amount of water by finding its average value t(s).
The method is simple and easy to implement and has high measurement accuracy. Suitable for rivers with small river flow.
However, there should be an appropriate drop between the overflow port and the receiving water body, or an aqueduct can be used to form an error.

3.Buoy method
Select a straight river reach, and measure the cross-sectional area of ​​the water flow within a 2m interval of the river reach. Find the area of ​​its average cross-section.
Drop buoys in the upper reaches of the river and measure the time it takes for the buoys to flow through the identified reaches (L).
Repeat the measurement several times to obtain the average value (t) of the required time.
The flow rate (L/t) can be calculated.
The flow can then be calculated as follows:

Q=60V*S

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

4.Flow meter method
By measuring the cross-sectional area of ​​the water flow, the river flow rate is measured with a current meter to calculate the river flow.
When measuring, the number of vertical measuring points and the number of horizontal measuring points need to be determined according to the depth and width of the channel.
This method is simple, but it is easily affected by water quality, and it is difficult to achieve continuous determination.

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

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

Read more about: Common River Water Level Measurement Methods

Battery operated electromagnetic flow meter-GRPS-new irrigation water flow meter

GPRS wireless remote electromagnetic flowmeter inherits the advantages and functions of the original electromagnetic flowmeter and supports GPRS wireless communication.

Only a mobile phone card with GPRS wireless Internet access function is required, and you can easily log in to the Internet and establish a connection with a remote computer without connecting other module devices. Support Kingview.

The battery-powered converter comes standard with a regular lithium battery pack that lasts 3–6 years. If equipped with a high-capacity lithium battery pack, the continuous working time will be longer.

It can easily realize remote monitoring of the electromagnetic flowmeter’s instantaneous flow, instantaneous flow rate, flow percentage, fluid conductance ratio, forward cumulative value, reverse cumulative value, alarm status and other data. With disconnection automatic connection function, support dynamic IP address.

This Battery operated electromagnetic flow meter has become the choice of many users.

How to Select the Right Agriculture Flow Meter

Due to the modernization of agriculture and the realization of precision agriculture, flowmeters are bound to play an increasingly important role in farmland irrigation.
Therefore, on the basis of a comprehensive comparison of the measurement methods and characteristics of various flowmeters on the market. You should choose flow meter products that are more in line with the requirements of farmland water conservancy irrigation, safe, reliable, economical and durable.

The principle of choosing a flowmeter is to have a deep understanding of the structural principles and fluid characteristics of various flowmeters. At the same time, the selection should be made according to the specific situation of the site and the surrounding environmental conditions. Economic factors must also be taken into account.

In general, you should choose from the following five aspects:

① Performance requirements of the flowmeter;

• Whether to measure flow (instantaneous flow) or total amount (cumulative flow);
• Accuracy requirements;
• Repeatability;
• Linearity;
• Flow range and range;
• Pressure loss;
• Output signal characteristics and flowmeter response time, etc.

② fluid characteristics;

• Fluid temperature and pressure
• fluid density
• Viscosity
• Chemical corrosion and scaling
• compression factor

③ Installation requirements;

• Field piping wiring
• The flow direction of the fluid
• The upstream and downstream straight pipe sections of the flowmeter
• Pipe diameter and pipe vibration
• The installation position of the valve
• Protective accessories
• Electrical connection and electromagnetic interference
• Pulsating flow and unsteady flow

④ Environmental conditions;

• Ambient temperature
• Ambient humidity
• Security
• Electrical interference

⑤ The price of the flow meter.

• Installation fee
• Running cost
• Testing fee
• Maintenance costs and spare parts costs, etc.

More water flow measurement and control solutions

Sino-Inst is Manufacturer of Irrigation Flow Meters. We supply more than 20 kinds of Irrigation Flow Meters. 60% magnetic flow meter, 20% ultrasonic flowmeters, and other types of flowmeters.

Irrigation Flow Meters are mainly used for flow measurement of Agriculture Water System.
It can measure even liquids such as water, seawater, oil, and slurry.

Irrigation Flow Meters enable stable water measurement and control. This greatly meets the measurement needs of many Farm and irrigation industry applications. Can be used from small to large tubes.

Sino-Inst’s Irrigation Flow Meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, the US, and other countries.

The entire team at Sino-Inst’s has received excellent training, so we can ensure that every client’s needs are met. For assistance with your product requirements, whether it’s a Irrigation Flow Meters, level sensor, or other device, give us a call.

Instrument constant of flow meters, i.e. Reynolds number

Reynolds number is an infinite parameter used as a criterion to determine the flow pattern of a fluid as it flows through a pipe. It is related to pipe diameter, flow rate, and medium viscosity.

The first used to determine the flow pattern of the fluid is turbulent flow through laminar flow. A side Re greater than 3200 or more can be judged as turbulent flow. Of course, from the laminar flow to the turbulent flow of the Reynolds number has a transition. So be specific and say that the Reynolds number must be greater than a certain value to say is to restore turbulent flow. Less than a certain value is said to be restored laminar flow.

Re = ρvd/μ, where v, ρ, μ are the fluid velocity, density and viscosity coefficient, d is a characteristic length. For example, if fluid flows through a circular pipe, d is the equivalent diameter of the pipe.

When measuring the flow rate of a fluid in a pipe, it is often necessary to understand its flow state, velocity distribution, etc. Reynolds number is to characterize the fluid flow characteristics of an important parameter.

Fluid flow inertia force Fg and viscous force (internal friction) Fm ratio called Reynolds number. Re is a factor less quantity.

The Reynolds number is small, which means that the fluid flow between the viscous force between the masses dominates, the fluid masses parallel to the inner wall of the pipe flow regularly, laminar flow state.

Reynolds number is large, which means that the inertia force dominates, the fluid is the turbulent flow state, general pipe Reynolds number Re < 2000 for laminar flow state, Re> 4000 for turbulent flow state, Re = 2000 ~ 4000 for the transition state.

In different flow states, the law of motion of the fluid. The distribution of velocity is different, so the average velocity of the fluid in the pipeline υ and the maximum velocity υmax ratio is also different. Therefore, the size of the Reynolds number determines the flow characteristics of viscous fluids.

When the external conditions are geometrically similar (geometrically similar pipes, fluid flowing through geometrically similar objects, etc.), if their Reynolds numbers are equal, the fluid flow state is also geometrically similar (hydrodynamically similar). This law of similarity is the basis for the standardization of flow measurement throttling devices.

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The influence of Reynolds number on the vortex flowmeter

The influence of Reynolds number on the vortex flowmeter in a certain range of Reynolds number. Vortex flowmeter output frequency signal with the volume of flow through the measuring tube between the relationship is not affected by the fluid properties (density, viscosity) and components. That is, the flow coefficient is only related to the vortex generator and the shape and size of the pipe.

Therefore, only in a typical medium in the calibration of its flow coefficient and applicable to a variety of media. This is a major advantage of the vortex flowmeter.

However, if the Reynolds number exceeds this range, it will have an impact.

Extended reading: Fluid flow meter types

Vortex flowmeter working principle

In the fluid flow in the pipeline set a vortex generator (resistance fluid). So in the volume downstream of the generator will alternately produce a regular vortex. This vortex is called Kaman vortex street.

The vortex generator is the main component of the detector. It is closely related to the flow characteristics (meter coefficient, linearity, range, etc.) and resistance characteristics (pressure loss) of the meter, and the requirements for it are as follows.

A vortex flowmeter can control the vortex in the direction of the axis of the vortex generator synchronous separation.
In a wide range of Reynolds numbers, there is a stable vortex separation point, maintaining a constant Strohal number.
The ability to produce a strong vortex street with a high signal-to-noise ratio of the signal.
Simple shape and structure, easy processing and standardization of geometric parameters, as well as installation and combination of various detection elements.
materials should meet the requirements of fluid properties, corrosion resistance, abrasion resistance, and resistance to temperature changes.
The inherent frequency is outside the frequency band of the vortex street signal.

Due to strict environmental requirements, some process industries, especially chemical, paper, and water treatment, are all placed under the strict monitoring of the agency. This will drive the vortex flowmeter production increase.

In addition, the privatization of municipal water treatment has become the trend, which will generate new investment to update the aging water treatment and sewer systems.

Multi-variable vortex flowmeters, which can measure temperature and pressure in addition to flow, are also in commercial use. Although its output is negligible, growth can be expected throughout the forecast period.

This enhanced measurement capability allows users to purchase fewer meters, requiring fewer process measurement points and thus fewer potential leak paths.

Read more about: How Vortex Flow Meter measure efficiently? For steam, gas, liquid 

Read more about: Coriolis Mass Flowmeter Working Principle

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Sino-Inst, Manufacturer for Vortex Flow Meters, like gas vortex flow meter, liquid vortex flow meter, sanitary vortex flow meter, insertion vortex flow meter, steam vortex flow meter, and natural gas vortex flow meter.

Sino-Inst’s vortex Flow Meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, the US, and other countries.

Thermal mass flow meter working principle

Thermal gas mass flow meter is designed on the basis of thermal dispersion. And adopts method of constant differential temperature to measuring gas flow. It has advantages of small size, easy installation, high reliability and high accuracy, etc.

The meter contains two platinum resistance temperature sensors. The thermal principle operates by monitoring the cooling effect of a gas stream as it passes over a heated sensor. Gas flowing through the sensing section passes over two sensors. One of which is used conventionally as a temperature sensor, whilst the other is used as a heater. The temperature sensor monitors the actual process values whilst the heater is maintained at a constant differential temperature above this by varying the power consumed by the sensor. The greater the gas velocity, the greater the cooling effect and power required to maintain the differential temperature. The measured heater power is therefore a measure of the gas mass flow rate.

The format of gas velocity and power is shown as below:

Where:

• ρg is the specific gravity of the medium
• V is velocity
• K is the balance coefficient
• Q is heater power
• Δ T is a differential temperature
• The medium temperature range of the meter is -40℃～220℃.

In the format (1), the specific gravity of medium is related to the density:

Where:

• ρg is the medium density in working condition（kg/m3）
• ρn is the medium density in standard condition, 101.325kPa, and 20℃ （kg/m3）
• P is the pressure in working condition（kPa）
• T is the temperature in working condition （℃）

In the formats (1) and (2), there is a certain functional relationship between the velocity and pressure in working condition, medium density, the temperature in working condition.

Due to the sensor temperature is always 30℃ higher than the medium temperature (environment temperature), and the meter adopts the method of constant differential temperature, therefore the meter do not need to do temperature and pressure compensation in principle.

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Know more about How Thermal Mass Flow Meter Technology Works?

Video source: https://www.youtube.com/watch?v=YfQSf2NBGqc

Thermal mass flow meter applications

The thermal measuring principle is widespread in the industry, and is being used successfully in many applications with gas flow, for example:

• Oxygen, nitrogen, hydrogen, chlorine, and multi-component gas measurement.
• Blast furnace gas and coke oven gas measurement.
• Flue gas measurement.
• Aeration and chlorine measurement in biogas and water treatment.
• Compressed air measurement.
• Gas flow measurement for natural gas, liquefied gas, flame gas, etc.
• Primary air and secondary airflow measurement of power plant blast furnace
• Flow measurement of underground ventilation or exhaust system

Further reading: Industrial LPG/Propane flow meter

Extended reading:
What is the K-factor in a flow meter?
Cryogenic Flow Meters|Liquid Nitrogen-Liquid Oxygen-LNG fluids

FAQ

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Related Products:

Sino-Inst offer over 10 Thermal Mass Flow Meters, with Best Price.

A wide variety of Thermal Mass Flow Meters options are available to you, such as free samples, paid samples. All of our flow meters can work with the AMS NEW TREX. About 13% of these are magnetic flow meter. 14% are Insertion Magnetic Flow Meter. 25% are Venturi flow meter. 13% are Handheld ultrasonic flow meter, and others are Liquid Turbine Flow Meters.

Sino-Inst is Thermal Mass Flow Meter suppliers, located in China. Mass flow meter products are most popular in North America, Mid East, and Eastern Europe.

The United States, and India, which export 99%, 1%, and 1% of Thermal Mass Flow Meter respectively.

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

Variable area flow meter principle

The principle of the variable area flowmeter is to keep the pressure drop constant and use the change of the throttle area to measure the flow rate. It consists of a tapered tube gradually expanding from bottom to top and a rotor or float placed in the tapered tube.

When the fluid flows through the tapered tube, the float in the tube is pushed up to a height corresponding to the flow rate and floats.

When the flow rate increases, the impulse acting on the rotor increases. Because the weight of the rotor in the fluid is constant. The rotor rises. The corresponding annular gap between the rotor and the tapered tube is also increased. The flow rate of the fluid flowing through the annulus decreases. Impulse is also reduced. Bring the rotor to balance in the new position. According to the float position of the rotor, the instantaneous flow value can be measured.

The advantages of area flow meters are simple structure, easy testing, and suitable for measuring small flow rates.

Its disadvantage is that it is easily affected by factors such as fluid density, pressure and viscosity. When testing the flue gas flow, because the flue gas contains dust, the area flowmeter cannot be used.

Extended Reading: What Is Metal Tube Flow Meter? Rotameter Manufacturer

Extended reading: Gas Rotameter Tips

Variable area flow meter advantages and disadvantages

• The advantages of the variable area flow meter are simple structure and easy testing, suitable for measuring small flow.
• The disadvantage of variable area flow meter is that it is easily affected by factors such as fluid density, pressure, and viscosity. When testing the flue gas flow, because the flue gas contains dust, the area flowmeter cannot be used.

Extended reading: Integral DP Flow Meter|Gas, liquid, steam|Compact structure

Variable area flow meter types

We can classify according to different product materials. Including the following categories:

Plastic variable area flow meter

The main parts such as the liquid plastic tube rotameter cone tube are made of AS, ABS plastic. Has relatively good corrosion resistance. The product also has the characteristics of reasonable structure, small size, lightweight, and the tapered tube is not easily broken. The plastic tube rotor flowmeter can be widely used in chemical, environmental protection, food, and other industrial sectors.

Glass variable area flow meter

Glass rotor flowmeters are mainly used in various departments such as the chemical industry, petroleum, light industry, medicine, fertilizer, chemical fiber, food, dyes, environmental protection, and scientific research. Used to measure the flow of single-phase non-pulsating (liquid or gas) fluids. The anti-corrosion glass rotor flowmeter is mainly used for the detection of corrosive liquid and gas medium flow. Such as strong acid, strong acid, oxidant, strong oxidizing acid, organic solvent, and other corrosive gas or liquid medium flow detection.

Extended reading: Fluid flow meter types

Metal variable area flow meter

Metal float flowmeter is a kind of flow measuring instrument commonly used in industrial automation process control. It has the characteristics of small pressure loss, large detection range (range ratio 10:1), and convenient use. It can be used to measure the flow of liquid, gas, and steam, and is especially suitable for medium flow measurement with low flow velocity and small flow.

The metal float flowmeter has local display type and intelligent remote transmission type, with pointer display, instantaneous flow, cumulative flow, liquid crystal display, upper and lower limit alarm output, cumulative pulse output, standard two-wire 4-20mA current output, etc. form. Provide users with a very wide choice of space.

Read more about: What is a Flow Meter? Types and how does it work?

Variable area flow meter applications

Because Variable area flow meter has the advantages of simple mechanical structure, convenient processing, stable work, high reliability and low pressure loss. Especially it can measure the characteristics of low Reynolds book small flow medium. Therefore, it is widely used in gas and liquid flow measurement and automatic control systems.

1. It is suitable for the measurement of small-caliber and low-velocity gas, liquid and steam flow.
2. Affected by a certain viscosity, it is not suitable to measure high-viscosity media
3. When the flow rate exceeds 100m3/h, the pressure loss is large.
   Mostly used for process control instruments, the best accuracy is 1%, generally 1.5%, and the range ratio is 10:1
4. It is not suitable for measuring medium with large density change. It is not suitable to measure the flow of pulsating medium (such as metering pump outlet).

To put it bluntly, even under the conditions of small flow rate, small diameter, low flow rate, low viscosity medium, and no magnetic coupling influence, the variable area flow meter is the best to use.

In addition, the installation of a Variable area flow meter is also very particular. For flow accuracy requirements too high, it is not suitable to use this flow meter!

Read more General-purpose Flow Totalizer for Data collection and calculation

Extended reading: non contact flow meter

Horizontal variable area flow meter

There are two installation directions for variable area flow meter: horizontal installation and vertical installation.

Horizontal installation is divided into left in and out, right in and out.

Vertical installation is divided into top in and bottom out, bottom in and top out.

This one is installed horizontally to measure nitrogen. It is purely mechanical to display instantaneous flow rate.

Read More about: What is the difference between rotameter and flowmeter?

Metal tube variable area flow meter

The metal tube variable area flowmeter is our rotameter.

The LZ series Rotameter Flowmeter provided by Sino-Inst adopts a 304/316 stainless steel structure. It can be used to measure the flow of liquid, gas and steam. Especially suitable for low flow velocity and small flow. Flow measurement of high temperature, high pressure, strong corrosion, conductive or non-conductive media.

Extended reading: Micro flow meters for low flow liquids

Vortex Flowmeter VS Rotameter

Vortex flowmeter and rotameter are two different flowmeters. The working conditions and use environments measured by each flowmeter are different. Therefore, the two flowmeters have their own advantages and disadvantages.

Rotameter is also called metal tube rotameter, which uses variable area measurement principle. Suitable for measuring liquid, gas and other measuring media. Its body uses all-metal structure. There are indication type, remote transmission type and explosion-proof type. Rotameter has 4-20mA standard analog quantity signal output and on-site indication. Especially its body is pointer type. This big advantage can be measured even without power. Widely used in power generation, pharmaceuticals, water treatment, etc.

Extended Reading: What is difference between rotameter and flow meter

The vortex flowmeter has two measurement types: the basic type and the temperature and pressure compensation integrated type. The basic model only measures a single flow rate. The temperature and pressure compensation type is a flow type that can measure temperature and pressure at the same time. The vortex flowmeter also has many advantages. It has the advantages of small pressure loss, large measuring range, high precision, and because the vortex flowmeter has no moving parts. Therefore, maintenance and installation are very simple.

Extended reading: How does a rotameter work

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Sino-Inst offers over 5 Variable area flow meters, with the Best Price.

A wide variety of Variable area flowmeters options are available to you, such as free samples, paid samples.

Sino-Inst is Variable area flowmeter supplier, located in China.

Variable area flowmeters products are most popular in North America, Mid East, and Eastern Europe.

The United States, and India, which export 99%, 1%, and 1% of Variable area flowmeters respectively.

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

Ultrasonic water flow meter types

According to the measurement principle

• Time difference method ultrasonic flowmeter;
• Frequency difference method ultrasonic flowmeter;
• Phase difference method ultrasonic flowmeter;
• Doppler ultrasonic flowmeter;
• Ultrasonic flowmeters for partially full pipes and river channels that combine liquid level measurement and average flow velocity measurement.

According to the way of use

• Portable ultrasonic flowmeter;
• Fixed (standard pipe section) ultrasonic flowmeter.

According to the installation method of the transducer

• Standard pipe section ultrasonic flowmeter;
• Clip-on ultrasonic flowmeter;
• On-site hole-opening Insertion Type Ultrasonic Flow Meter.

According to whether the transducer is in contact with the fluid

• Intrusive (contact) ultrasonic flowmeter;
• Non-invasive (non-contact) ultrasonic flowmeter.

According to the nature of the measured fluid

• Liquid ultrasonic flowmeter;
• Gas ultrasonic flowmeter.

According to the number of transducer channels

• Mono ultrasonic flowmeter;
• Two-channel ultrasonic flowmeter;
• Multi-channel ultrasonic flowmeter.

Extended reading: 2 inch Water Flow Meter

Featured Ultrasonic water flow meters

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

Why is it more appropriate to use a Doppler ultrasonic flowmeter to detect sewage pipes?

What kind of flow monitoring equipment should you choose for ordinary sewage pipes?

What kind of flow monitoring equipment should we choose for ordinary sewage pipelines?

The electromagnetic flowmeter can only measure the condition of the full tube. Therefore, the measurement result will be unstable when the tube is not full. Because the non-full tube state can be understood as an extreme situation in which a large number of bubbles exist in the measured liquid medium.

There are two situations when the pipe is not filled with liquid. One is that the liquid level is higher than the level of the electrode. The other is lower than the level of the liquid being measured.

When the liquid level in the pipe is higher than the electrode level. If the front and back straight sections of the pipeline are in an ideal state at this time. Generally, the precision data measured by electromagnetic flow is relatively stable. However, because the flow meter liquid contains the gas volume in the pipeline, there is undoubtedly a large measurement error in this measurement state.

When the electrode is higher than the level of the electrode, the electrode is exposed in the air at this time. The measurement circuit is actually in an open state, and the electrode cannot directly contact the liquid. The value and output are in a random state. If the electrode is constantly shaking or full, the electrode will not work normally, and the measurement will not be carried out.

The measurement of the intelligent electromagnetic flowmeter is not only inaccurate, but also damages the electrodes.

However, many sewage pipes are caused by partial pipes. Only when it rains does the tube become full. So what kind of flow measurement method is the most appropriate in such a situation?

At present, the most advanced technology in China is the use of a Doppler ultrasonic flowmeter. Such as rain and sewage pipes. It can accurately monitor the water level, flow rate, flow rate and instantaneous flow rate, cumulative flow rate, water temperature, and other data. It can be refreshed in real-time, and the installation is very simple.

Extended reading: Ultrasonic flow detectors types

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Sino-Inst, Manufacturer for Ultrasonic water flow Meter. It can measure a single sound-conducting liquid medium of DN 15—150mm. It can measure even liquids such as water, seawater, oil, and slurry.

Sino-Inst’s Ultrasonic water flow meters, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, the US, and other countries.

Request a Quote

Residential Water Meters Types

The types of water meters can be divided by the principle of measurement. The common types are mechanic water meters, mechanical water meters equipped with electronic devices, and electronic water meters.

Read more about Everything You Need To Know About Electronic Flow Meters

Their working principles are as follows:

Read More about: Chemical Flow Meter Guide

Related Products

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Where is the Residential water meter installed?

In order to be beautiful and save space, water meters are generally installed in their own kitchens. Some of them will be installed in the corner of the kitchen or covered by other kitchen furniture.

However, in order to facilitate the reading of the water meter, it is best to install the water meter in a conspicuous position.

If the house has a special type, it may be installed outdoors.

Extended reading:
What is the K-factor in a flow meter?
Cryogenic Flow Meters|Liquid Nitrogen-Liquid Oxygen-LNG fluids

Precautions for installation of Residential water meter

1. If it is to install a water meter on a new pipeline. You have to rinse all the stolen goods in the pipeline first. This will prevent the water meter from slowing down or not moving in the later stage.
2. It is better to install a filter before the water meter is installed. Before installing other instruments in the pipeline, the debris in the pipeline should be cleaned up. Avoid clogging of pipes.
3. When installing, keep the direction on the watch case consistent with the direction of the water flow. And the place where the water meter is installed. The location should be convenient for us to read or change later. The place where the water meter is installed should not be installed in a place exposed to the sun and freezing.
4. When the water meter is installed, the reading side should be facing up.
5. The direction of the arrow on the water meter should be the same as the direction of the water flow in the pipe.
6. If the water meter is installed outdoors, it must be protected against sun and frost. Because the outdoor environment is better than the indoor environment. If the water meter is exposed to the sun or cold for a long time, the service life of the water meter will be affected. If the gear of the water meter is exposed to the sun for a long time. It will cause deformation and damage. This will affect the accuracy of water meter measurement.

Extended reading: Beginner’s Guide: Variable area flow meter

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Sino-Inst offers over 30 residential water meter products.

A wide variety of residential water meter options are available to you, such as free samples, paid samples.

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

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

Sino-Inst sells through a mature distribution network that reaches all 50 states and 30 countries worldwide. residential water meter products 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.

Mechanical flow meter types

There are many types of flow meters.

The electromagnetic flowmeter is based on the electromagnetic principle. When a conductive fluid flows through an electromagnetic field, the velocity of the fluid can be obtained by measuring the voltage.

Ultrasonic flow meters use the principle of ultrasonic acoustics to measure flow velocity. The mechanical flow meter is a relative concept.

Compared with other flow meters, the mechanical flowmeter relies on the rotation and displacement of mechanical parts to measure the flow rate. Common mechanical flow meters have the following categories.

Tool: Volumetric Flow Rate & Pipe Diameter to Flow Speed Calculator

Read more about: Beginner’s Guide: Variable area flow meter

Featured Mechanical Flow Meters

Extended reading: High-Temperature Oval Gear Heating oil Flow Meter

Of course, if you are not clear about the principle and difference of the above flow meters. Can not choose the appropriate Mechanical Flow Meters. Then, you can also choose the appropriate Mechanical Flow Meters according to the fluid conditions that need to be measured.

Extended reading:
What is the K-factor in a flow meter?
Cryogenic Flow Meters|Liquid Nitrogen-Liquid Oxygen-LNG fluids

Below are some of our experience sharing, hoping to help you find the right Mechanical Flow Meters.

No matter which Mechanical Flow Meters you choose. The signal output by Mechanical Flow Meters, such as 4-20mA. The flow signal can be connected to a paperless recorder. Carry out multi-channel flow signal monitoring.

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

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Mechanical Flow Meter Selection Guide

How to choose the most suitable mechanical flowmeter for you? It is recommended to refer to the following points:

Remember, there’s no one-size-fits-all solution. Take the time to review these steps and make the right decision for your specific application. Happy flow meter shopping!

Mechanical flow meter price

Sino-Inst offers Mechanical Flow Meters with best price. Please contact our sale engineer for quotation.

Sino-Inst offers over 50 Mechanical Flow Meters for flow measurement. About 50% of these are differential pressure flow meters, 40% is the turbine flow sensor, and 20% are dp flow meters and gear flow meters.

A wide variety of Mechanical 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.