Selection Guide

What is a mechanical flow meter?

Mechanical flow meters are a type of flow meters that use arrangement moving parts to measure flow. The fluid passes through a series of gears or chambers (positive displacement or PD) or through a rotating turbine or rotor. Mechanical flowmeter is different from electromagnetic and ultrasonic in principle. Mechanical flow meters easily monitor liquid flow rates for water, fuels, viscous fluids and more.

Mechanical Flow Meters

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

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 meter working principle

The positive displacement flow meter is a flow meter that uses mechanical measuring elements to continuously divide the fluid into a single known volume, and repeatedly fill and discharge the volume of fluid to accumulate the total amount of fluid.

Read more about: positive displacement flowmeter

A Rotameter flow meter is a variable area flow meter based on float position measurement. It is suitable for liquid and gas volumetric flow measurement and control.

Rotameter flow meter working principle

When the measured fluid passes through the annulus formed by the cone and floats from the bottom to the top. The differential pressure produced at the upper and lower ends of the float forms the force for the float to rise. Until the rising force equals the weight of the float immersed in the fluid, the float will stabilize at a certain height.
The height of the float in the tapered tube and the flow rate through it correspond to each other.

Read more about Rotameter flow meter-Variable Area Flow Meters

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

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 Flow Meter Working Principle

The fluid flows through the sensor housing. Because the blades of the impeller have a certain angle with the flow direction. The impulse of the fluid makes the blades have a rotational torque. After the friction torque and fluid resistance are overcome, the blades rotate. The speed is stable after the torque is balanced.
Under certain conditions, the speed is proportional to the flow rate.

Read more about Turbine Flow Meter Working Principle

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℃).

Gear flow meter working principle

With the flow of the medium, the gears mesh and rotate. Under the action of the fluid flow, a pressure difference is formed at both ends of the instrument inlet and outlet. There is no need for power supply. A pair of gears rotate freely. The cavity between the gears is filled with liquid. Discharge and measure the number of revolutions of the gear to know the flow of liquid and liquid flowing through the instrument.

Read more about Gear flow meter for Microflow

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.

Mechanical water flow meters refer to a type of flow meter suitable for clean water processes or applications. The working principle of a mechanical water flow meter is to measure the speed of water flowing through a pipe. This causes the piston or turbine to rotate. The volume flow of water is proportional to the rotation speed of the blades. Compared with electronic water flow meters, mechanical water flow meters may become clogged when the water is dirty or contains large particles. When the water flow is low, the mechanical water meter does not work well.

In most cases, we will choose an electromagnetic flowmeter to measure the flow rate of water. But if it is pure water and cannot conduct electricity, then an electromagnetic flowmeter cannot be used. You can choose a turbine flowmeter to measure.

Extended reading: 2 inch Water Flow Meter

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

Diesel Fuel Flow Meters

Diesel Fuel flow meters are digital flow meters for liquid fuel consumption measurement.

Most widely used types are mechanical and digital inline fuel meters. Differential flow sensors are avilable. Like: the turbine, positive displacement (oval gear), Coriolis, and differential pressure flow meters.

Read more about: Diesel Fuel Flow Meters

Industrial Fuel Flow Meters

The oval gear flowmeter is particularly suitable for measuring high viscosity media. And it is not sensitive to changes in the viscosity of the liquid being measured.

Measurable medium:
Fuel, diesel, gasoline, heat transfer oil, hydraulic oil, kerosene, tar, petroleum, crude oil, asphalt, resin and other liquids. Especially suitable for the measurement of high viscosity liquids.

Read more about:

LCD display Oval Gear High Viscosity Flow Meter

T-series Coriolis Mass Flowmeter for High Viscosity Liquids


A mechanical gas flow meter is a precision instrument used to measure the volume of gas flowing through a pipe. It is typically used in industrial and commercial applications where accurate measurement of gas flow is critical.

Mechanical flow meters that can measure gas flow mainly include metal float flow meters and turbine gas flow meters. And orifice plate meter.

A Rotameter flow meter is a variable area flow meter based on float position measurement. It is suitable for liquid and gas volumetric flow measurement and control.

Gas turbine flow meter is a velocity flow meter that measures gas flow. For natural gas, nitrogen, and gas trade measurement.

Relatively speaking, the cost of gas turbine flow meters is higher than that of Rotameter flow meters. But the service life will be longer.

Extended reading: How does a rotameter work

Extended reading: Gas Rotameter Tips

For cryogenic fluids, such as liquid nitrogen, liquid oxygen, etc. It can reach -196 degrees Celsius.

For cryogenic fluids, we provide gear flow meters and low-temperature turbine flow meters.

You can choose the right one according to the flow range.

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

Mechanical oil flow meters are devices that measure the rate of oil flow. They are often used in industrial and commercial applications to monitor the rate of oil consumption or production.

There are several different types of mechanical oil flow meters, each designed for a specific application. The most common type of mechanical oil flow meter is the positive displacement (PD) meter. PD meters measure the volume of oil that passes through the meter by displacing a fixed amount of fluid with each revolution of the measuring chamber. This type of meter is very accurate and is often used in applications where precise measurement is critical.

Another type of mechanical oil flow meter is the turbine meter. Turbine meters measure the rate of oil flow by measuring the speed of a rotating turbine blade. Turbine meters are less accurate than PD meters but are more resistant to fouling and clogging.

Read more about: oil flow meter types

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


Flow Metering Principals
Differential Pressure Flowmeters
Velocity Flowmeters
Positive Displacement Flowmeters
Mass Flowmeters
For Open Channel Flowmeters – weirs, flumes, submerged orifices, current meters, acoustic flow meters, and more
For different working principle, We offer different types of flow meters, like:
Differential Pressure Flow Meters
Orifice Plate
Venturi Tube
Flow Nozzles
The Sonic Nozzle – Critical (Choked) Flow Nozzle
Calorimetric Flowmeter
Ultrasonic Doppler Flowmeter
Positive Displacement Flowmeter
Variable Area Flowmeter or Rotameter
Velocity Flowmeters
Pitot Tubes
Electromagnetic Flowmeter
Turbine Flowmeter
Vortex Flow Meter
Thermal Flowmeter
Coriolis Flowmeter
Mass Flowmeters
Open Channel Flowmeters

Read more about: Flow Meter Selection Guide

Residential water meters can measure the water consumption of a household.
Industrial water meters mainly refer to water flow meters. Can measure the amount of industrial water. For example, the amount of wastewater discharged.
Extended reading: 2 inch Water Flow Meter

Digital flow meter is a flow meter with digital display and signal output. Digital flow meter refers to a flow meter with digital display and signal output.Different digital flow sensors include turbine, thermal mass, electromagnetic, ultrasonic, orifice plate, venturi. The different designs of the flowmeters have a variety of applications. With 4-20ma, RS485, or others output.
Extended reading: Hot Water Flow Meters Improve Heating-Boiler System

Mechanical flowmeters are generally equipped with pointer display heads.
The pointer indicates the instantaneous flow.
Above is a single cumulative flow, which can be reset;
Below is the total accumulated flow, which cannot be reset.

Extended Reading: Insertion Flowmeter Types

The choice between a mechanical and a digital flow meter really depends on your specific needs. Mechanical flow meters, such as positive displacement or turbine flow meters, are often more cost-effective and simpler to use. However, digital flow meters, like electromagnetic or ultrasonic ones, offer higher precision, more data output, and need less maintenance. So, if you value accuracy over cost, a digital flow meter might be the better choice.

An example of a mechanical flow meter is the turbine flow meter. In a turbine flow meter, the fluid moves a turbine in the meter, and the rate of rotation of the turbine is converted into a flow measurement. They are widely used in applications where a high degree of accuracy is not essential, such as water distribution and HVAC.

Flow meters can be broadly categorized into several types, but here are three common ones:

a. Differential Pressure Flow Meters: These measure the flow rate by introducing a constriction in the flow. This creates a pressure drop, which can be correlated with flow rate.

b. Positive Displacement Flow Meters: These measure flow by repeatedly filling and emptying compartments with the fluid to be measured.

c. Velocity Flow Meters: These measure the velocity of the flow and convert it to the flow rate. Examples include turbine, electromagnetic, and ultrasonic flow meters.

A mechanical water flow rate meter is a device that measures the rate of water flow in a pipeline. It usually employs moving parts, such as a turbine or a set of rotating gears, which move proportional to the flow of water. This movement is then translated into flow rate data.

A mechanical water flow meter works by using the flow of water to move parts of the device. For example, in a turbine flow meter, water flows through the meter, causing a turbine to spin. The rotation speed of the turbine is directly proportional to the water flow rate. In a positive displacement meter, a known volume of water is allowed to fill a chamber, and the number of times this chamber is filled and emptied represents the flow rate.

The accuracy of a mechanical water flow meter can vary based on the specific type of meter and the conditions of use. Generally, they offer moderate to high accuracy. For example, turbine flow meters usually have an accuracy within ±1% of the reading, while positive displacement meters can be even more accurate. However, mechanical meters are subject to wear and tear over time, which can impact accuracy, so regular maintenance is recommended.

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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:

  • Identify Your Needs: Understand your application. Is it for irrigation, industrial use, or residential water supply? Different applications may have different flow rate, accuracy, and durability needs.
  • Consider the Fluid: What type of fluid are you measuring? The viscosity and corrosiveness of the fluid can affect the meter’s performance.
  • Evaluate the Flow Rate: Check the flow rate range required for your application. Mechanical flow meters like turbine and positive displacement meters have different suitable flow rate ranges.
  • Review Installation Requirements: Consider the pipe size, location, and installation orientation. Some flow meters have specific installation requirements to work optimally.
  • Check the Accuracy Level: How accurate does your measurement need to be? Choose a flow meter with an accuracy level that matches your needs.
  • Budget: Determine how much you’re willing to spend. Keep in mind that the cost of the meter itself is not the only factor – also consider the cost of installation and ongoing maintenance.
  • After-Sales Support: The manufacturer’s reputation and the quality of after-sales support can be crucial, especially for complex meters.

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.