Working principle and application of thermal gas mass flow meter

With the development of new energy technology, natural gas is more and more widely used in many new energy industries, and the thermal gas mass flowmeter has become a suitable instrument for measuring high pressure gas measurement. Below we analyze from the perspective of product performance and installation cost, why the thermal gas mass flowmeter can become a suitable low degree meter in high pressure natural gas measurement.

Thermal Gas Mass Flow Meter is also divided into flange link Thermal Gas Mass Flow Meter and plug-in link Thermal Gas Mass Flow Meter, The following describes the application scope of the Thermal Gas Mass Flow Meter.

In the industrial field, companies need to use natural gas, hydrogen and other gas in many process production, sometimes also need oxygen, nitrogen, argon and other made of gas, this part of the gas cost needs to be controlled and monitored, and the selection of monitoring instruments need to consider various issues:

The thermal gas mass flowmeter is an instrument for measuring fluid flow by using the principle of heat conduction. The instrument uses constant temperature difference method to accurately measure the gas mass flow.

The thermal gas mass flowmeter is an instrument for measuring fluid flow by using the principle of heat conduction. The instrument uses constant temperature difference method to accurately measure the gas mass flow. The most important thing is that the range ratio of this flowmeter is very wide, which greatly meets the measurement needs of the owner.

Direct measurement of gas mass, without temperature, pressure compensation of gas flow measurement instrument, it represents the development trend of gas flow measurement. The thermal mass flowmeter sensor part is composed of two reference platinum resistance temperature sensors, using a bridge loop, one sensor measures the fluid temperature, and the other sensor is a heating element, maintaining a constant temperature difference higher than the fluid temperature, that is, when the gas flows through the heating element, the heat is taken away, and the heat is proportional to the flow rate of the gas and the density of the gas. To maintain a fixed temperature difference between the two temperature sensors requires the circuit to provide more power to the heating element, and the amount of output power in the circuit is related to the mass of the fluid, thus measuring the flow rate.

Measuring medium: Various gases (except acetylene gas)
Pipe diameter range: DN10-2000mm
Accuracy Degree: ±1～2.5%
Pipe material: Carbon steel, stainless steel, plastic, etc

Thermal gas mass flowmeter is the use of fluid flowing through the pipe heated by an external heat source when the temperature field changes, is a high-sensitivity, high-precision gas measurement instrument, in the gas flow measurement conditions, good stability, used for gas process control and gas flow measurement one of the most used instruments.

In practical applications, thermal mass flowmeters require careful attention to various factors to ensure accurate and reliable measurement of fluid flow rates. Here are some key considerations for the practical application of thermal mass flowmeters:

When selecting a thermal mass flowmeter, several important factors should be taken into consideration to ensure it meets the requirements of the application and provides accurate and reliable measurements. Here are key points to pay attention to:

Thermal gas mass flowmeter has certain operating procedures and precautions in use, and must pay attention to these points when in use:

Installing and debugging a thermal mass flowmeter correctly in the early stages is crucial to ensure accurate and reliable measurements. Here are some precautions to take during installation and debugging:

1. Principle of thermal gas mass flowmeter

Thermal gas mass flowmeter The thermal distributed flowmeter uses the flow fluid to transfer heat to change the heat conduction distribution effect of measuring the temperature distribution of the tube wall. 2) King’s Law using the heat dissipation (cooling) effect. And because the structure of the detection element extends into the measuring tube, also known as immersion or intrusion type. Some instruments that are inserted from outside the tube into the process tube when in use are called plug-in.

One of the key advantages of thermal mass flow meters is their quick response time, enabling real-time monitoring and control of gas flow in dynamic processes. Moreover, these meters are known for their low pressure drop, minimizing energy consumption and preserving the efficiency of the overall system. With no moving parts, thermal mass flow meters also offer low maintenance requirements, reducing downtime and operational costs for industries relying on precise gas flow measurements.

Response speed: 1s
Output signal: 4-20mA (Photoelectric isolation, large load 500Ω)、
pulse、RS-485 (photoelectric isolation)、HART agreement
Alarm: 1-2 relay normally open contact、10A/220V/AC、*/30V/DC
Type of supply: Separate structure, integrated structure
Pipe material: Carbon steel, stainless steel, plastic, etc
Field display: Four lines of Chinese liquid crystal display
Display content: Mass flow, standard volume flow, cumulative flow, standard time, cumulative running time, standard flow rate, etc
Protection grade: IP65
Sensor material: Stainless steel Stainless steel, carbon steel

The thermal gas flowmeter adopts the principle of thermal diffusion, and the thermal diffusion technology is a technology with excellent performance and high reliability under harsh conditions. Typical sensing elements of thermal gas mass flowmeters include two thermal resistors (PT100), one is a speed sensor and one is a temperature sensor that automatically compensates for changes in gas temperature.

At the heart of a thermal mass flow meter is a sensor that heats up a portion of the gas stream while monitoring the temperature difference between the heated and unheated sections. As the gas flows over the heated sensor, it carries away heat, and the temperature difference provides a direct measurement of the mass flow rate. The beauty of this method lies in its ability to provide accurate readings across a wide range of flow rates, from low to high velocities, ensuring versatility and reliability in various industrial settings.

Structural form: plug-in pipelined
Measuring medium: All gases (except acetylene)
Pipe diameter range: Caliber DN32 or higher DN10～DN2000mm
Velocity range: 0.1～120Nm/s
Precision: ±1～2.5%
Operating temperature: Sensor：-40℃～+220℃
convertor：-20℃～+45℃
Working pressure: Medium pressure≤2.5Mpa
Medium pressure≤4.0Mpa
Power supply: DC24V or AC220V≤18W

Thermal gas mass flowmeter as a gas flowmeter, the application is very wide, today we specifically understand the use of thermal gas mass flowmeter:

The data show that in the flow measurement failure probability, the improper selection of flowmeter accounts for about 70%, and the quality of flowmeter products or other reasons account for 30%, which shows how important the selection of flow measurement is.

The medium of one of the two tubes of the thermal gas mass flowmeter does not flow, and the medium of the other tube flows. By comparing the Coriolis force of two pipes to obtain the flow rate, it is convenient to eliminate the natural vibration of the pipeline, the vibration of the fluid itself and other factors that affect or interfere with the measurement.

The reason why the thermal gas mass flowmeter is so popular is mainly due to its many advantages and wide application scenarios. Here’s a breakdown of why it’s popular:

Thermal gas mass flowmeter due to its various advantages and characteristics, now has been widely used in various industries flow measurement, in the actual measurement of thermal gas flow meter technical advantages are more and more obvious, the following we on the thermal gas mass flowmeter application occasions and some of their own technical advantages do some introduction, hope to be useful to you:

The origin of the thermal gas mass flowmeter is from the hot wire anemometer. The temperature of the platinum heating wire has a proportional relationship with the change in the flow rate of the fluid: the faster the flow rate, the more heat is taken away.

In-line thermal mass flowmeter is equipped with the same process pipe with the same inner diameter as the field pipe. The connection with the field pipe is flange connection or thread connection. Pipe segment sensor applicable pipe diameter: DN15 ~ 2000mm.

Measuring medium: Various gases (except acetylene gas)
Pipe diameter range: DN10-2000mm
Accuracy Degree: ±1～2.5%
Pipe material: Carbon steel, stainless steel, plastic, etc

Thermal mass flowmeters are widely used in various industries due to their ability to measure the flow rate of gases accurately. Here are some applications of thermal mass flowmeters across different industries:

The thermal gas mass flowmeter uses the principle of thermal diffusion, and its working principle determines the change of the measured medium gas with the temperature and pressure, which affects the data change of the measured results.

The selection of flue gas flowmeter is a complicated but critical process, which is directly related to the accuracy of measurement results and the reliability of equipment. Here are some of the main factors to consider in the selection process:

Thermal mass flowmeters are known for their ability to provide accurate and reliable measurements of fluid flow rates, regardless of changes in pressure and temperature. This resilience to pressure and temperature variations is due to the operating principle of thermal mass flowmeters and their design features. Here’s why thermal mass flowmeters are not significantly affected by changes in pressure and temperature:

Thermal gas mass flowmeters are a type of mass flowmeter specifically designed for measuring the flow rate of gases, while mass flowmeters, in a broader sense, can measure the flow rate of both gases and liquids. Here are some key differences between thermal gas mass flowmeters and other types of mass flowmeters:

The thermal gas mass flowmeter is an instrument that uses the principle of heat conduction to measure flow. The instrument uses the constant temperature difference method to accurately measure the gas mass flow rate. It has the advantages of small size, high digitization, easy installation, accurate measurement and so on.

The thermal mass flowmeter is an device for measuring gas flow by using the principle of thermal diffusion. The sensor consists of two reference thermal resistors (RTDS). One is the speed sensor RH, and the other is the temperature sensor RMG, which measures the temperature change of the gas. When the two RTDS are placed in the measured gas, one sensor RH is heated and the other sensor RMG is used to sense the measured gas temperature. As the gas flow rate increases, the airflow carries away more heat, and the temperature of the sensor RH drops.

Measuring medium: Various gases (except acetylene gas)
Pipe diameter range: DN10-2000mm
Accuracy Degree: ±1～2.5%
Pipe material: Carbon steel, stainless steel, plastic, etc

The thermal gas mass flowmeter is an instrument that uses the principle of heat conduction to measure flow. The instrument uses the constant temperature difference method to accurately measure the gas mass flow rate. It has the advantages of small size, high digitization, easy installation, accurate measurement and so on.