What is a Gas Flow Meter

I. What is a Gas Flow Meter

A gas flow meter is an instrument that measures the flow of a gas. It is installed in the pipeline to record the amount of gas flowing through. It can measure various gases including air, nitrogen, acetylene, phosgene, hydrogen, natural gas, liquefied petroleum gas, hydrogen peroxide, flue gas, methane, butane, chlorine, carbon dioxide, oxygen, compressed air, argon, toluene, benzene, xylene, hydrogen sulfide, sulfur dioxide, ammonia, and so on.

What is a Gas Flow Meter

II. The Main Types of Flow Meters

The thermal gas mass flow meter uses the principle of thermal dispersion, a technology known for its excellent performance and high reliability under harsh conditions. Its typical sensing elements include two RTDs (platinum RTDs), a velocity sensor, and a temperature sensor that automatically compensates for changes in gas temperature. When the two RTDs are placed in a medium, one of the sensors (the velocity sensor) is heated to a constant temperature above the ambient temperature, while the other sensor measures the medium temperature. The gas mass flow rate is calculated based on the amount of heat transfer through the sensing element. An increase in gas flow rate results in more heat being carried away by the medium, causing a subsequent decrease in the sensor temperature. To maintain a constant temperature, it is necessary to increase the working current through the sensor. This increase in current is proportional to the flow rate of the medium.

Thermal Gas Mass Flowmeter (4)

 

A vortex flow meter is mainly used for measuring the flow of medium fluids in industrial pipelines, such as gas, liquid, vapor, and other media. It is characterized by low pressure loss, a wide range, and high accuracy. The measurement of the flow volume under working conditions is almost independent of the fluid’s density, pressure, temperature, viscosity, and other parameters. With no moving mechanical parts, it offers high reliability and low maintenance. The instrument parameters remain stable for a long time. The instrument uses a piezoelectric stress sensor, ensuring high reliability and can operate in a temperature range of -20 ℃ to +250 ℃. It provides both analog standard signals and digital pulse signal outputs, making it easy to integrate with computers and other digital systems. It is a more advanced and ideal flow meter.

Vortex-flowmeter-wafer-type

  • V cone flow meter

The V-cone flow meter is widely used in petrochemical, natural gas, and other fields due to its simple structure, durability, ease of replication, versatility, affordability, and more. The V-cone flow meter overcomes the drawbacks of traditional throttling devices such as standard orifice plates, venturis, and nozzles. These traditional devices are prone to wear and tear, have high-pressure loss, limited range (range ratio), stringent installation conditions, and require long straight sections. In contrast, the V-cone flow meter can accurately measure the flow rate of various fluids across a wide range of Reynolds numbers.

When compared to ordinary differential pressure flow meters, the STV series V-cone flow meter offers high accuracy, long-term stability, good repeatability, minimal sensitivity to installation conditions, wear resistance, a wide measurement range, suitability for dirty media, low-pressure loss, and a long service life. It can be widely used in various fields and is suitable for measuring water, oil, various liquids, steam, air, natural gas, gas, liquefied petroleum gas, organic gases, oil residue, and more.

The integration of an orifice plate flow meter, consisting of a standard orifice plate and a multi-parameter differential pressure transmitter (or a differential pressure transmitter, temperature transmitter, and pressure transmitter), forms a high range ratio differential pressure flow device. This device can measure the flow of gases, vapors, liquids, and natural gas, and is widely used in the petroleum, chemical, metallurgy, electric power, heating, water supply, and other process control and measurement fields.

Orifice Plate Steam Flowmeter

 

  • Valeba flow meter

The Williba flow meter is suitable for high-precision flow measurement of gas, liquid, and steam. It is a differential pressure, rate averaging flow sensor that measures flow through the differential pressure generated by the sensor in the fluid. The Williba accurately reflects the true flow rate of the fluid with an accuracy of ±1.0% and a repeatability of ±0.1%. An outstanding advantage of the Williba is its ability to output a very stable, pulsation-free differential pressure signal.

The low-pressure orifice of the Williba achieves intrinsic anti-blocking. Generally, dust, sand, and particles are concentrated at the rear of the probe by the vortex force. This phenomenon is similar to how autumn leaves are always concentrated at the back of a house when the wind is blowing. Other probes, which have their low-pressure pick-up holes located in the vacuum area at the rear of the probe, are quickly blocked by impurities carried by the vortex. The unique design of the Williba has the low-pressure orifices located on both sides of the probe at the side and rear, in front of the fluid separation point and the tailrace area. This design inherently prevents clogging and produces a very stable low-pressure signal.

III. The Main Areas of Application

  • Industrial production

Flow meters are one of the major types of process automation instruments and devices. They are widely used in metallurgy, electric power, coal, chemical, petroleum, transport, construction, textile, food, medicine, agriculture, environmental protection, and people’s daily lives, as well as other areas of the national economy. Flow meters are important tools for the development of industrial and agricultural production, energy saving, improving product quality, and enhancing economic efficiency and management levels. They occupy an important position in the national economy.

In process automation instrumentation and devices, flow meters have two major functions: detecting instruments for process automation control systems and measuring the total amount of materials.

  • Energy measurement

Energy is divided into primary energy (coal, crude oil, coal bed methane, liquefied petroleum gas and natural gas), secondary energy (electricity, coke, artificial gas, oil, liquefied petroleum gas, steam) and energy-carrying substances (compressed air, oxygen, nitrogen, hydrogen, water) and so on. Energy measurement is an important means of scientific management of energy, energy conservation and improve economic efficiency. Flow meter is an important part of the energy measurement instrument, water, artificial gas, natural gas, steam and oil these commonly used energy are using an extremely large number of flow meters, they are indispensable tools for energy management and economic accounting.

  • Environmental protection engineering

Smoke, waste liquids, sewage, and other emissions seriously pollute the atmosphere and water resources, posing a significant threat to human survival. With sustainable development established as a national policy, environmental protection has become the most critical issue of the 21st century. To control air and water pollution, it is essential to strengthen management, and the basis of management is the quantitative control of pollution levels.

China relies on coal as its primary energy source, and millions of chimneys across the country constantly emit flue gas into the atmosphere. Controlling flue gas emissions is a crucial project for eradicating pollution. Each chimney must be equipped with flue gas analysis instrumentation and flow meters, forming a comprehensive emission monitoring system. Managing the flow of flue gas is challenging due to the varying sizes and irregular shapes of chimneys, the different gas compositions, the wide range of flow rates, and the presence of dirt, dust, corrosion, and high temperatures, along with the absence of straight pipe sections.

  • Transportation

There are five modes of transportation: railway, road, air, water, and pipeline. Although pipeline transport has existed for a long time, its application is not widespread. With the increasing prominence of environmental issues, the characteristics of pipeline transport have attracted attention. Pipeline transport must be equipped with flow meters; these are essential tools for control, distribution, scheduling, safety supervision, and economic accounting.

  • Biotechnology

The 21st century will usher in the century of life sciences, biotechnology as the characteristics of the industry will be rapid development. Biotechnology needs to monitor the measurement of many substances, such as blood, urine and so on. Instrumentation development is extremely difficult, a variety of varieties.

  • Scientific experiments

Scientific experiments require not only a large number of flow meters, but also a variety that is extremely complex. According to statistics, more than 100 kinds of flow meters are needed for scientific research. These are not mass-produced and are not available for sale in the market. As a result, many scientific research institutions and large enterprises have set up special groups to develop custom flow meters.

IV. Summary

Choosing the right type of flow meter involves several steps. First, understand the advantages and disadvantages of each type of flow meter. Next, fully understand the physical and chemical properties of the medium and the installation site. Then, consider the process conditions and the environment. Finally, know the user’s requirements for measurement accuracy. Additionally, ensure that the media flow rate falls within the flow meter’s range, and that the installation site meets the flow meter’s installation requirements. Also, consider any circumstances and factors that may affect the flow meter’s measurement.

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