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

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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.

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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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Read more about: Flow Meter Selection Guide

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

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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

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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.

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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.

Chilled Water Flow Meter Types

There is no best water flow meter, only the most suitable water flow meter. Because the application details of each pipeline are different. According to the actual measurement situation, select the most suitable flowmeter. Can save a lot of time and cost.

Featured Chilled Water Flow Meters

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What are the limitations of electromagnetic flowmeters at low temperatures?

Electromagnetic flowmeter transmitters are bound by two aspects when measuring cryogenic media.

Can ultrasonic flowmeter measures chilled water flow?

1. Ultrasonic flowmeter can measure flow. The temperature does not exceed -40℃~160℃. It is required to have a full tube and a uniform medium. It can display instantaneous flow, flow velocity, accumulated flow, accumulated running time, etc.
2. Ultrasonic calorimeter can measure heat supply, flow and temperature monitoring. Air conditioning heating and cooling capacity measurement.

When you place an order, you can specify whether it is to measure flow or heat. We will help you choose the model.

Extended reading: Industrial VS Residential inline water flow meters

How to measure the chilled water flow of the chiller?

The following is our experience sharing: Freezer chilled water flow measurement techniques. Hope it can be helpful to you.

1.Water pressure detection of the water inlet and outlet pipes of the freezer

Through the detection of the return water pressure and the outlet water pressure value. Check the water flow rate of the freezer under the pressure difference between the inlet and outlet water in the random manual of the freezer.

By referring to the corresponding table or diagram of the unit’s water flow in the manual. So as to determine whether the freezer system is normal.

And through this difference to determine which section of the water pipeline has a higher resistance value. And make corresponding rectification plans and actions.

Read more: Insertion Type Ultrasonic Flow Meter Applications

2.Detection of the return water temperature and outlet water temperature of the refrigerator (the unit needs to be in normal state)

30 minutes after starting up, check the system or chilled water system inlet and outlet thermometers through the parameters of the unit’s control system.
It can read the inlet water temperature and outlet water temperature when the unit is running. The difference must be about 4-6 degrees.

If the temperature difference between the inlet and outlet water is too large, it means that the water flow of the water system through the plate is too small. This may cause the unit to fail to operate normally or be damaged.

3.Water pump running current detection

By detecting the running current of the refrigerator water pump, it is compared with the rated current. It can be judged whether the actual water flow is larger or smaller than the rated water flow of the pump.

Comprehensive judgment together with the previous parameters. In order to get an exact test and analysis report of the chiller system.

4.Detection of the suction temperature of the compressor copper pipe (only when the refrigeration is running)

If it is 30 minutes after the refrigerating and freezer is turned on

It is detected that the suction temperature of the compressor is lower than 0 degrees. It means that the water flow in the water-side heat exchanger is not enough, which leads to a drop in the evaporation temperature and the evaporation pressure.

And cause Freon is still evaporating and absorbing heat in the suction pipe that flows from the evaporator to the compressor. Will cause the compressor suction temperature to be lower than 0 degrees.

In addition, it is necessary to eliminate the drop in evaporation pressure and evaporation temperature caused by the water temperature set point being too low.

The non-standard low water temperature unit can be considered normal as long as the compressor has a suction superheat of 6-8℃.

So under normal water flow. The suction temperature of the compressor is generally greater than 0°C. Below this value, water system problems need to be ruled out.

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Sino-Inst offers over 50 Chilled Water Flow Meter for flow measurement. About 50% of these are magnetic flow meters, 40% is the turbine flow sensor, and 20% are Ultrasonic 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.

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

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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.

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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.

Industrial oil flow meters measure the volume or mass of oil. Can realize the mutual conversion of volume and mass.

The main industrial oils are hydraulic oil. Gear Oil. Turbine oil. Compressor oil. Refrigeration oil. Transformer oil. Cylinder oil, heat treatment oil, heat transfer oil, etc. Of course, edible oil can also be produced in the industry. In addition, there are greases with lubricating oil as base oil and thickening agent.

Therefore, whether it is a company that uses, trades, or produces oil, it needs to accurately measure the oil flow.

There are many common oil flow meters, such as turbine flow meters, positive displacement flow meters, gear flow meters, mass flow meters, etc.

Then, we need to choose a suitable flow meter that meets the measurement and budget according to different working conditions.

Oil flow meter digital

Oil flow meter digital refers to an oil flow meter with a local digital display function. The flowmeter can be configured with local digital display, pointer display, and without local digital display. Therefore, it is determined whether the digital display function is needed according to the needs of users.

Explore Oil and Gas Flow Meters

Oil flow meter 4-20ma

The signal output by the flowmeter is generally a pulse signal or a 4-20mA current signal, both of which output instantaneous flow.

The flowmeter voltage signal is unstable. It is simply disturbed during long-distance transmission. The current signal is relatively stable.

The current signal is used in the transmission process, and the voltage signal (the range of voltage value) is used for detailed control in the control instrument (integrator) and DCS system.

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Mechanical oil flow meter

The mechanical oil flow meter is a type of flow meter. The mechanical flowmeter is a purely mechanical measuring component. Such as turbine flowmeter, rotameter, etc. Relatively speaking, for example, ultrasonic flowmeters use ultrasonic principles instead of mechanical principles. So the ultrasonic flowmeter is not a mechanical flowmeter.

How is oil flow measured?

Oil is generally transported through pipelines. There are many ways to measure oil flow. For example, use the oil tank level difference to calculate the oil flow. Of course, the simplest and most effective way is to use a flow meter.

Although the types of oil flow meters are different, their working principles are different. However, they can all help us achieve a goal. That is to measure and monitor the flow of oil. Instantaneous flow, cumulative flow, etc.

So that we can better control production and trade.

Extended reading: What Is Hydraulic Flow Meter?

Oil flow meter types

At present, the following types of flow meters can be used to measure oil: Turbine flow meters. Gear flow meter. Vortex flowmeter. Ultrasonic flow meter. Mass flowmeter. Differential pressure flow meters.

You can find a suitable flow meter in the appropriate type of oil flow meter according to your needs. Of course, maybe, you don’t know what type of flowmeter you should use.

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Next, we recommend suitable flow meters for some commonly used oils.

Extended Reading: Petroleum Flow Meter

Of course, the above are just our suggestions. If you need to choose the right flow meter. You can contact Sino-Inst sales engineers. We will provide you with the most suitable measurement solution.

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Sino-Inst offers over 30 Industrial Oil Flow Meters for flow measurement. About 50% of these are Turbine flow meters, 40% is the mass flow sensor, and 20% are DP flow meter.

A wide variety of Industrial Oil 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.

Fluid flow meter principle

Principles of mechanics:

• Instruments that belong to this type of principle include differential pressure type and rotor type using Bernoulli’s theorem.
• Impulse type and movable tube type using the momentum theorem.
• Use the direct mass formula of Newton’s second law.
• Target type using the principle of fluid momentum.
• Turbine type using the angular momentum theorem.
• Vortex type and vortex street type using the principle of fluid oscillation.
• Pitot tube type and volume type, weir, trough type, and so on using total static pressure difference.

Principles of Electricity:

Instruments used in this type of principle include electromagnetic, differential capacitive, inductive, strain resistance, etc.

Acoustic principle:

Ultrasonic type is used for flow measurement using acoustic principles. Acoustic type (shock wave type) and so on.

Thermal principle:

There are calorimetric, direct calorimetry, indirect calorimetry, etc., which use thermal principles to measure flow.

Optical principle:

Laser type, photoelectric type, etc. are instruments that belong to this type of principle.

Based on physical principles:

Nuclear magnetic resonance, nuclear radiation, etc. are instruments that belong to this type of principle.

Other principles: There are marking principles (tracing principles, nuclear magnetic resonance principles), related principles, etc.

Extended reading: U-series Liquid Mass Flow Meter | Liquid-slurry flow measure

Fluid flow meter types

1. According to the measurement objects, there are two categories: closed pipes and open channels.
2. According to the principle of measurement, there are mechanical principles, thermal principles, acoustic principles, electrical principles, optical principles, atomic physics principles, etc.
3. According to the purpose of measurement, it can be divided into total measurement and flow measurement. The meters are called total meter and flow meter respectively.

Liquid flow meters can be divided into: anti-corrosion flow meters. Liquid flow meters.. Differential pressure flow meters. Ammonia flow meters. Turbine flow meters. Electromagnetic flow meters. Vortex flow meters in fluid oscillating flow meters. Mass flow meters.

Hydraulic fluid flow meter

Industrial Hydraulic oil flow meter, also called hydraulic flow meter gauge. Hydraulic oil flow meters are inline flow meters for hydraulic oil flow measurement.

Sino-Inst offers Turbine, Mass flow, Oval gear, V-cone, Target, and Orifice flow meters for inline hydraulic oil flow. Features like: bidirectional, high pressure, analog, can be customized as customer need.

Extended reading: What Is Hydraulic Flow Meter?

Ultrasonic fluid flow meter

The ultrasonic flow meter measures the liquid flow rate quickly and effectively. There are two types of ultrasonic flowmeter technology: Doppler frequency shift and transit time.

Transit time ultrasonic flow meter is most suitable for measuring the flow of cleaning liquid. Therefore, it is the most popular type of ultrasonic meter.

Doppler ultrasonic flow meter can measure the frequency difference of sound waves reflected from bubbles or particles in the airflow. It is suitable for aerated or dirty liquids.

Fluid mass flow meter

Fluid mass flow meter directly measures the mass flow of the medium passing through the flow meter. It can also measure the density of the medium and indirectly measure the temperature of the medium.

A flow measuring instrument that measures the mass flow in the pipeline. The measured fluid is under the condition that the pressure, temperature and other parameters change greatly. If only the volume flow is measured, the change in fluid density will bring about a large measurement error.

In positive displacement and differential pressure flowmeters, the density of the fluid to be measured may vary by 30%, which will cause an error of 30 to 40% in the flow rate.

With the improvement of automation level, many production processes have put forward new requirements for flow measurement. The chemical reaction process is controlled by the quality (not the volume) of the raw materials.

The heating and cooling effects of steam and air flow are also proportional to the mass flow.

The strict control of product quality, accurate cost accounting, and fuel control of airplanes and missiles all require precision. Therefore, the mass flow meter is an important flow measuring instrument.

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Fluid Flow Meters Selection Guide

How to select the flowmeter？

It can be considered from five aspects. These five aspects are flow meter performance, fluid characteristics, installation conditions, environmental conditions and economic factors. The detailed factors in the five areas are as follows:

1. Instrument performance: accuracy, repeatability, linearity, range, flow range, signal output characteristics, response time, pressure loss, etc.;
2. Fluid characteristics: temperature, pressure, density, viscosity, chemical corrosion, abrasiveness, fouling, miscibility, phase change, electrical conductivity, speed of sound, thermal conductivity, specific heat capacity, isentropic index;
3. Installation conditions: pipeline layout direction, flow direction, length of the upstream and downstream side of the test piece, pipe diameter, maintenance space, power supply, grounding, auxiliary equipment (filter, getter), installation, etc.;
4. Environmental conditions: ambient temperature, humidity, electromagnetic interference, safety, explosion-proof, pipeline vibration, etc.;
5. Economic factors: instrument purchase, installation, operation, calibration, maintenance, instrument service life, spare parts, etc.

The flowmeter selection steps are as follows:

1. According to the fluid type and five consideration factors, the available instrument types are initially selected (there are several types for selection);
2. Collect data and price information for the primary selection type. Prepare conditions for in-depth analysis and comparison;
3. Use the elimination method to gradually concentrate on 1 or 2 types. It is necessary to repeatedly compare and analyze the five factors to finally determine the pre-selection target.

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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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What is a mass flow meter?

Air mass flow meter, namely Mass Flow Meter (abbreviated as MFM). It is an instrument for accurately measuring gas flow. The measured value is not inaccurate due to temperature or pressure fluctuations. No temperature pressure compensation is required.

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What is a mass flow controller?

The mass flow controller (abbreviated as MFC) not only has the function of the mass flow meter. More importantly, it can automatically control the gas flow. That is, users can set the flow according to their needs. MFC automatically keeps the flow constant at the set value. Even if the system pressure fluctuates or the ambient temperature changes. It will not deviate from the set value.

Simply put, the mass flow controller is a steady flow device. It is a gas steady flow device that can be set manually or connected to a computer for automatic control.

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What does a mass air flow meter do?

Industrial Air mass flow meter is a meter used to measure the flow of industrial gas pipelines. The mass flow meter directly measures the mass flow of the medium passing through the flow meter. It can also measure the density of the medium and indirectly measure the temperature of the medium.

Since the transmitter is an intelligent instrument with a single-chip microcomputer as the core, more than a dozen parameters can be derived for users to use based on the three basic quantities mentioned above.

The mass flow meter has flexible configuration, powerful functions and high performance-price ratio. It is a new generation flow meter.

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What is the principle of a mass flow controller?

The mass flow controller is composed of a flow sensor, a diverter channel, a flow regulating valve and an amplifying controller.

The flow sensor uses the principle of capillary heat transfer thermometry to measure the mass flow of gas (without temperature and pressure compensation).

The flow signal measured by the sensor heating bridge is sent to the amplifier for amplification. The amplified flow detection voltage is compared with the set voltage, and then the difference signal is amplified to control the regulating valve. The closed loop controls the flow through the channel to make it equal to the set flow.

The flow divider determines the flow of the main channel.

A regulated power supply and a digital voltmeter are provided on the flow display instrument matched with the mass flow controller. Set potentiometer, peripherals, built-in conversion and three-position valve control switch, etc.

Extended reading: How To Reduce The Effect Of Pressure On The Mass Flow Meter?

How to understand the flow unit of a mass flow meter/mass flow controller?

Gas mass flow units are generally expressed in sccm (Standard Cubic Centimeter per Minute, standard milliliters per minute) and slm (Standard Liter per Minute, standard liters per minute).

This means that under different conditions of use, the indicated flow rate is the flow rate in the standard state.

The standard state requirements are: air pressure—101325Pa (760mm Hg); temperature—0℃ (273.15K). This is an important difference between this meter and other flow meters, and it is also the difference between sccm and slm from mL/min and L/min.

For most users, the expression method of volume flow is very habitual. Easy to use. But there are also users who need to know the mass of the medium flowing in a unit of time (such as g/min). This requirement is very easy to achieve. Because the gas density in the standard state is a constant. , Can be easily found, so it can be realized by simply doing a multiplication (multiplying the density by several slm). Therefore, the volume flow rate in the standard state is equivalent to the mass flow rate.

When to use a mass flow meter and when to use a mass flow controller?

Generally speaking, when only measuring or monitoring the flow, use a mass flow meter.

When you need to control the flow, use a mass flow controller.

For some measurement occasions, both can be used. For example, when measuring the flow capacity of capillary tubes, use a mass flow meter when measuring flow at a constant pressure.

When measuring pressure with constant flow, a mass flow controller is required.

Note that when the mass flow controller is in the cleaning state. It can also be used as a mass flow meter. It’s just that the pressure drop is larger than that of ordinary mass flow meters.

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What are the main advantages of mass flow meters/mass flow controllers?

(1) Flow measurement and control are not inaccurate due to temperature or pressure fluctuations.

For most flow measurement and control systems, it is difficult to avoid system pressure fluctuations and environmental and medium temperature changes. For ordinary flow meters, fluctuations in pressure and temperature will cause larger errors. For mass flow meters/mass flow controllers, it can generally be ignored.

(2) Automation of measurement control

The mass flow meter/mass flow controller can output the flow measurement value as a standard electrical signal output.

In this way, it is easy to realize digital display of flow, automatic measurement of accumulated flow, automatic data recording, computer management, etc.

For mass flow controllers, automatic flow control can also be realized.

Generally, the analog MFC/MFM input and output signals are 0~+5V or 4~20mA, and the digital MFC/MFM is also equipped with RS232 or RS485 digital serial communication ports. It can be easily connected to a computer for automatic control.

(3) Accurately control flow

The mass flow controller can accurately control the given amount of gas. This is particularly useful for flow control in many processes, and for proportional control of different gases.

(4) Wide scope of application

• With a wide working pressure range, our products can range from vacuum to 10MPa.
• Can be applied to a variety of gas media (including some corrosive gases, such as HCL).
• There is a wide flow range. The minimum flow range of our products can reach 0～5 sccm, and the maximum flow range can reach 0～200 slm.
• The resolution of the flow display can reach 0.1% of the full scale.
• The flow control range is 2~100% of full scale (range ratio is –50:1). Therefore, it is widely used in many fields.

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What are the disadvantages of mass flow meters? What are the fears of using mass flow controllers?

Relative to cheap rotameters, the main disadvantage of mass flow meters is that they are relatively expensive.

There are four fears when using a mass flow controller:

First fear of dust. If dust enters the flowmeter, it will block the sensor and the diverter, causing measurement errors. It is required to install a filter before the air inlet;

The second fear is that liquid and oil will enter the MFC. It will cause loss of control. If the outlet of the MFC is connected to a liquid tank, a check valve must be added to the outlet of the MFC to prevent the liquid from returning;

The third fear of using moist corrosive gas. Moist and corrosive gases will rust the stainless steel and cause damage to the MFC channel. Therefore, it is required to dry the gas and the MFC piping system before using the corrosive gas;

Fourth, fear not operating in accordance with safety rules when using highly corrosive, flammable, explosive, toxic, and other hazardous gases. It may cause product damage and other more serious losses. Correct use and safe operation are important to every user.

Extended reading: Stainless steel flow meters|304-316 optional

Can mass flow controllers be used to control corrosive and special gases? How to choose sealing materials?

Mass flow controllers can be used to control various gases, including corrosive gases and special gases.

But it should be noted that for the use of corrosive gas and special gas, it is necessary to select the model and sealing material appropriately.

When ordering, the user needs to make a special statement to the supplier that the gas is used. In order to avoid serious losses due to wrong selection or selection of sealing materials.

Generally, the wet materials of the gas mass flow controller that contact the working gas are 316L stainless steel, polytetrafluoroethylene, and sealing materials. Sealing materials are divided into two categories: metal seals and rubber seals.

The material of the metal seal is generally corrosion-resistant materials such as stainless steel, gold or nickel.

In principle, MFC with metal seal can be used for any gas. Including various corrosive gases and special gases.

For strong corrosive gases such as boron tribromide, boron trichloride, hydrogen fluoride, and metal oxide gases used in MOCVD, it is recommended to use metal-sealed MFC.

Due to the high price of metal-sealed MFCs, rubber-sealed MFCs are usually used where the requirements are not high.

If there is no special statement, all MFCs are sealed with fluorine rubber. It can be used for most acidic and alkaline corrosive gases. For example, it can be used for halogenated dry gases such as hydrogen chloride.

Some other special corrosive gases require special rubber.

Ammonia-Ammonia resistant rubber, such as ethylene-propylene rubber, neoprene rubber or nitrile rubber is required. Organic solvent vapor (acetone, toluene, etc.)-silicone rubber is required. Boron tribromide, boron trichloride, hydrogen fluoride, etc.-need to use perfluoro rubber.

Sino-Inst offer over 5 Air mass flow meters and controller with Best Price.

A wide variety of Air mass flow meters and controller options are available to you, such as free samples, paid samples. More about Types Of Air Flow Measurement Instruments.

Sino-Inst is Air mass flow meters and controllers suppliers, located in China. Mass Flow Meters products are most popular in North America, Mid East, and Eastern Europe.

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2 Magnetic flow meter calibration methods

At present, there are 2 solutions for Magnetic flow meter calibration: direct and indirect.

Direct Magnetic flow meter calibration is the excitation coil inspection method. This method is also known as the “dry standard” method of electromagnetic flowmeters. Indirect calibration is the external clamp-on ultrasonic flowmeter calibration method. Also known as the “non-contact measurement method”.

However, in the “dry standard” method, the standard coil is directly designed into the meter body of the flowmeter. The performance of its resistance and other indicators cannot be traced regularly.

As a result, it is impossible to determine whether the measurement characteristics of the standard coil change after a period of time. Therefore, “dry standard” is difficult to effectively realize the traceability of the value.

Compared with the “dry standard” method of detection. The external clamp ultrasonic flowmeter is capable of non-stop flow and non-cutting of pipes. The advantages of on-site Magnetic flow meter calibration are not affected by the temperature, pressure, and density of the fluid being measured.

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Magnetic flow meter calibration procedure

Clamp-on ultrasonic flowmeter calibration electromagnetic flowmeter

Calibration method: non-contact measurement method. That is, the external ultrasonic flowmeter is clamped on the pipe of the measured flowmeter. By comparing the cumulative flow error of the two flowmeters. Determine the measurement characteristics of the flowmeter being inspected.

The external ultrasonic flowmeter calibration method is used for on-site calibration. The inspector should first check whether the input of the key parameters that affect the accuracy of the measurement built in the flowmeter converter is correct.

Ask the staff about the daily flow rate, and observe and calculate the average flow rate of the flowmeter over a period of time.

Big data compared with standard equipment in the laboratory according to the standard table. Enter the pipe diameter of the standard meter and the flow meter to be inspected. Calibration coefficients, outer diameter, wall thickness and other parameters similar to the flow rate. According to the flowmeter’s online operating instructions on-site actual measurement input.

The cumulative flow method is used when calculating the indication error. Read the cumulative value of the flow of the standard meter and the meter under inspection for a certain period of time in three times. As the standard value of the measurement standard meter and the displayed value of the tested flow meter. Each measurement time is 30min.

Conditions permit or when the flow rate changes significantly within a day. Three flow points with obvious differences can be measured.

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Real flow calibration electromagnetic flowmeter

How do you calibrate a magnetic flow meter?

• Select the corresponding pump according to the pipe diameter and flow rate for the verification test;
• If the system uses compressed air power. Turn on the air compressor to reach the air source pressure required by the system. To ensure the rapid switching of the commutator and the normal operation of the clamp meter;
• After the flowmeter is correctly installed and connected. It should be energized and preheated for about 30 minutes under the requirements of the verification regulations;
• If the high tank water source is used, check whether the overflow signal of the stabilized water tower appears.
• Before the formal test. According to the requirements of the verification regulations, use the verification medium to circulate the time in the pipeline system. At the same time, check whether there is any leakage in the sealing parts of the pipeline;
• Before starting the formal verification, the verification medium should be filled with the flowmeter sensor to be tested. Then turn off the downstream valve to adjust the zero position;
• When starting the verification, first open the valve at the front of the pipeline. Slowly open the valve behind the flow meter under test to adjust the flow at the verification point.
• During the calibration process, the flow stability of each flow point should be within the 1% ~ 2%-flow method, while the total amount law can be within 5%. When completing the verification process of a flow point, the temperature change of the verification medium should not exceed 1℃. When completing all the verification processes, it should not exceed 5℃. The pressure downstream of the inspected flowmeter should be high enough to ensure that no flashing and cavitation occur in the flow pipeline (especially in the reduced diameter);
• After each test, the valve at the front end of the test pipeline should be closed first. And then the pump should be stopped to avoid emptying the voltage stabilizing facility. At the same time, empty the remaining verification medium in the test pipeline. Then turn off the control system and the air compressor.

Extended Reading: Guide: Magnetic Flowmeter Installation

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Magnetic flow meter calibration frequency

The verification period for flowmeters with accuracy grades of 0.2 and better than 0.2 is 1 year. For flowmeters with accuracy grades lower than 0.2 and using quoted errors, the verification period is 2 years.

The electromagnetic flowmeter is a flowmeter that calculates the flow rate by setting a magnetic field perpendicular to the flow direction in a closed pipeline. By measuring the induced electromotive force generated by the movement of the conductive liquid in the magnetic field.
　　
The National Metrological Verification Regulations of the People’s Republic of China JJG 1033-2007 “Electromagnetic Flowmeter” 7.4 The verification period stipulates: The verification period of the flowmeter accuracy level of 0.2 and better than 0.2 is 1 year. For the accuracy level less than 0.2 The maximum verification period for the current level and usage reference error is 2 years.

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Do magnetic flow meters require calibration?

Mainly depends on your working conditions. If the measurement requirements are high. There are more impurities and dirt in the fluid and poor environmental conditions. Electrode fouling affects the measurement. The measurement is inaccurate after cleaning and repair. It can be verified. If the working conditions are good, the long-term use is normal. No verification is necessary.

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Sino-Inst flow calibration device and electromagnetic flowmeter production test standard

The manufacture of high-quality electromagnetic flowmeters is inseparable from high-precision flow calibration devices. The flow calibration device is the standard equipment for measurement departments and flowmeter manufacturers for value transmission, traceability and verification testing.

The Sino-Inst team has developed and built a set of high-level water towers as a voltage stabilization source. The static mass method is combined with the standard meter method, and is dedicated to the calibration device of the electromagnetic flowmeter.

The device uncertainty is better than the first-class fluid flow device level of 0.05%. It has passed the appraisal and audit of the Shaanxi Metrology Institute.

The 35-meter-high, 200-cubic-volume water tower is designed with a special overflow device. The fluctuation of the water level and liquid level during calibration measurement does not exceed 8mm. A high stability of better than 0.01% is achieved.

The production of MFE needs to go through various performance tests in a standard laboratory by an authoritative engineer before it can be put on the market.

Electromagnetic compatibility test

Electrostatic discharge (ESD) immunity GB/T 17626.2/ICE 61000-4-2
Electrical fast transient/pulse group (EFT/B) immunity GB/T 17626.4/ICE 61000-4-4
Surge (lightning strike) immunity GB/T 17626.5/ICE 61000-4-5
Power frequency magnetic field immunity GB/T 17626.8/ICE 61000-4-8

Environmental test

High and low-temperature cyclic impact test GB/T2423.1 GB/T2423.2
Salt spray test GB/T2423.17 GB/T6458
Vibration and shock test GB/T2423.10
Hazardous Substance Testing (RoHS): X-ray fluorescence spectroscopy testing IEC62321

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Sino-Inst offer over 50 Magnetic Flow Meters, with Best Price.

A wide variety of Water Flow Meters options are available to you, such as free samples, paid samples.

About 13% of these are magnetic flow meter, 14% are Insertion Magnetic Flow Meter, 25% are Venturi flow meter, 13% are ultrasonic flow meter, and others are Liquid Turbine Flow Meters.

Sino-Inst is Magnetic Flow Meters supplier, located in China. Magnetic Flow Meters products are most popular in North America, Mid East, and Eastern Europe. The United States, and India, which export 99%, 1%, and 1% of Magnetic Flow Meters respectively.