How to improve the measurement accuracy of thermal gas mass flowmeter

Thermal gas mass flowmeter has a wide range of applications in many fields, its high precision, rapid response and stability characteristics make it in a variety of gas flow measurement occasions can play an excellent performance, for the development of various industries to provide more reliable technical support.

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:

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.

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:

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

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.

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

The thermal gas mass flowmeter is an instrument that uses the principle of heat conduction to measure fluid flow. The instrument uses the constant temperature difference method to measure the gas flow accurately. It has the advantages of small size, high digitization, easy installation and accurate measurement. Today we are mainly to talk about the thermal gas mass flowmeter in the installation process need to pay attention to what are?

The thermal mass flowmeter is a flow meter based on the principle of thermal diffusion. The device uses the constant temperature difference method to measure the gas accurately. It has the advantages of small size, high digitization, easy installation, accurate measurement and so on.

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

Due to the continuous development of thermal gas mass flow meter is based on the principle of thermal diffusion, that is, the use of fluid flow through the heated object, the heated object of the heat dissipation of how much with the fluid flow rate into a certain proportional relationship. Specifically, the flow meter’s sensor has two standard and the RTD, has been used as a heat source, has been used to measure the fluid temperature, the fluid flows through, the heat loss of the heat source and the size of the flow into a non-linear relationship, the thermal gas mass flowmeter can be converted into a measurement of this relationship to measure the flow rate of the signal of the linear output.

How to improve the accuracy of thermal gas mass flow meter?

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:

Common faults encountered with thermal mass flowmeters can disrupt their accurate measurement capabilities. Here are some typical issues along with potential solutions:

The thermal gas mass flowmeter is an instrument that uses the principle of heat conduction to measure flow. The instrument adopts constant temperature difference method for gas mass flow sensor part consists of two reference platinum resistance temperature sensors. Using a bridge loop, one sensor measures the flow temperature and the other maintains a constant temperature difference above the fluid temperature, allowing flow measurement under high temperature and high pressure conditions.

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 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.

Although the thermal gas mass flowmeter has many advantages in this respect, it can not be used for large pipe runoff measurement, pressure loss is relatively large, and the price is more expensive, which limits its measurement application in natural gas long distance pipeline.

At present, oxygen generator in the production process will be affected by external influences, more and more enterprises for fine management, energy consumption, cost accounting and other requirements for the loss of this part of the oxygen measurement.

Thermal gas mass flowmeter can be used to measure any gas that does not contain condensed liquid in various shapes and materials (such as round pipe, square pipe, rectangular pipe, etc., diameter from 8mm-10000mm or larger, all kinds of metal, plastic, cement material), it does not need temperature and pressure compensation, directly measure the mass flow of fluid.

The correct use of gas flowmeters is the key to ensure accurate and reliable measurement results. The following is the correct use of gas flowmeters:

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.

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:

Thermal gas mass flowmeter adopts the principle of thermal diffusion, and thermal diffusion technology is a technology with excellent performance and high reliability under harsh conditions.

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

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 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 order to solve the problem of leakage caused by poor measurement accuracy or inability to measure below the lower limit of the instrument, a new type of thermal gas mass flowmeter is developed based on the theory of forced convection heat transfer and the principle of hot wire anemometer. The sensitivity of the instrument is greatly improved and the dead zone of the instrument is reduced by using microfilament structure in the sensitive element and the velocity measuring heating element.

Thermal mass flowmeters offer several advantages and disadvantages, which are important to consider when selecting a flow measurement solution. Here are some of the key advantages and disadvantages:

Like the flue gas, this medium has a higher temperature, contains more impurities such as solid dust, the general application of large caliber, flow rate range is relatively wide, so the measurement is more difficult, so in the selection and use of flue gas flow timing should pay attention to the characteristics of the power plant flue wind speed, pay attention to the principle of choosing sensors, It is also necessary to pay attention to the wear resistance, corrosion resistance, dirt resistance and high temperature resistance of the sensor, and select the appropriate measurement position to ensure the measurement accuracy.

The thermal gas mass flowmeter is designed based on the principle of thermal diffusion. The meter uses constant temperature difference method to measure the gas accurately. The thermal gas mass flowmeter has the advantages of small volume, high digitization, easy installation and accurate measurement.