Thermal Gas Mass Flow Meter

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Product details

Product Overview
Thermal gas mass flow meter is an advanced instrument that uses the principle of heat diffusion to achieve accurate gas flow measurement. Its core sensor consists of two reference-level thermal resistors (RTDs), one of which is used as a velocity sensor RH and is continuously heated during operation; the other acts as a temperature sensor RMG, which is responsible for sensing the real-time temperature of the measured gas. When the gas flows in the pipeline, the heat of the velocity sensor RH will be taken away faster as the gas flow rate increases, causing its temperature to drop. By measuring the temperature difference between the two sensors and combining the mathematical relationship corresponding to King's law, the mass flow rate of the gas can be accurately calculated. This measurement method overcomes the disadvantages of traditional measurement methods that are affected by temperature and pressure fluctuations, and truly realizes direct and accurate measurement of gas mass flow.

Working Principle
Thermal gas mass flow meter operates based on the principle of heat diffusion. When two RTD sensors are placed in the measured gas, the velocity sensor RH is heated to a specific value higher than the gas temperature, and the temperature sensor RMG monitors the actual temperature of the gas. As the gas flows, gas molecules continuously collide with the velocity sensor RH, taking away its heat and lowering its temperature. According to King's law of thermal effect, there is a certain mathematical relationship between heating power P, temperature difference △T (i.e. TRH - TRMG) between speed sensor RH and temperature sensor RMG, and mass flow Q: P/△T = K1 + K2 f (Q) K3, where K1, K2, and K3 are constants related to the physical properties of the gas. Through microelectronic control technology, the instrument converts this relationship into a linear output flow signal, thereby accurately measuring the gas mass flow.

Model	Insertion type/pipe segment type
Measurement medium	various gases (except acetylene)
Pipe diameter range	DN80-DN6000 DN15-DN2000
Flow rate range	0.5-100Nm/s
Accuracy	±1%
Working temperature	Sensor（Normal temperature type）： -10℃-100℃
	Sensor（High temperature type）： -10℃-100℃
	Converter: -10C-45℃
Working pressure	≤4.0MPa ≤16MPa
Power supply	24VDC or 220VAC (power consumption ≤18W)
Response speed	1s
Output signal	4-20mA (photoelectric isolation, maximum load 500 ohms) RS485 communication
Pipeline material	carbon steel, stainless steel, plastic, etc. Display: 8-bit field + 24 prompts
Display memory	standard volume flow, cumulative flow, standard time, cumulative running time, etc.
Primary meter protection level	IP65
Primary meter explosion-proof level	ExdIICT4
Sensor material	stainless steel

Performance characteristics
Fast response: sensitive to changes in gas flow, response time ≤850ms, can sense flow fluctuations and output signals in a very short time, and provide real-time feedback on flow dynamics, meeting application scenarios such as rapid adjustment of gas flow during chemical reactions and real-time monitoring of engine intake flow, which require high timeliness of response to flow changes.

No temperature and pressure compensation: The unique measurement principle enables it to directly measure gas mass flow, without interference from temperature and pressure changes, without the need to install additional temperature and pressure compensation devices, and without complex temperature and pressure correction calculations, which greatly simplifies the measurement process and reduces equipment costs and subsequent maintenance difficulties.

Easy installation: Various installation methods such as plug-in and pipe segment are provided. The plug-in sensor can be installed and maintained online. First, weld the base with external threads on the outer wall of the pipe, install the ball valve and drill a hole, and then insert the sensor into the center of the pipe (the insertion position is determined at the factory). It is suitable for pipes with a diameter of DN80-6000mm; the pipe segment type is equipped with a process pipeline that matches the inner diameter of the on-site pipeline at the factory, and is connected to the on-site pipeline through flanges or threads. It is suitable for pipes with a diameter of DN15-2000mm. The installation process is simple and has low requirements for on-site construction conditions.

Easy maintenance: There are no complex moving parts. The core sensor components are made of durable materials such as 316L stainless steel, tantalum, titanium, etc., which have strong vibration and impact resistance and are not easy to damage. Some products support online plug-in cleaning and maintenance, and the maintenance operation is simple, which can effectively reduce downtime, reduce maintenance costs, and improve production efficiency.

Widely applicable media: In addition to acetylene gas, it can measure most single gases and mixed gases, including clean gas, dusty and sandy gas, corrosive gas, wet gas, etc. It can work stably in complex gas measurement scenarios in many industries such as petrochemical, metallurgy, electric power, and environmental protection, and has strong adaptability.

Meiante Technology Co., Ltd. mainly deals in various measuring instruments, including Level Instrument, Flow Meters, Pressure Instruments, Temperature Instrument and Calibration Instrument, etc.

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