Technical principle
The ST10 thermal gas mass flowmeter is based on the principle that the rate of heat absorption is directly related to the mass flow rate. The sensor of this instrument consists of two reference stage thermal resistors. One is the mass velocity sensor T1, and the other is the temperature sensor T2 for measuring the temperature of the gas. When these two RTDS are placed in the gas to be measured, sensor T1 is heated to a constant temperature difference above the gas temperature, and the other sensor T2 is used to sense the temperature of the gas to be measured. As the mass flow rate of the gas increases, the gas flow takes away more heat, and the temperature of sensor T1 drops. To maintain a constant temperature difference between T1 and T2, the heating power of T1 needs to be increased. According to King’s Law of the thermal effect. When moving gas molecules collide with a thermal resistor, they absorb and carry away heat. The greater the flow rate, the more molecules come into contact with the thermal resistor, and the more heat is absorbed. Heat absorption is related to the number of molecules of a certain gas, its thermal properties, and flow characteristics. The heating power P, temperature difference Δ T (T1-T2), and mass flow rate Q have a definite mathematical relationship: P/ Δ T=K1+K2 f(Q)K3. K1, K2, and K3 are constants related to the physical properties of the gas.

Product Features
Measure the mass flow rate of gas without the need for temperature and pressure compensation
The range ratio is large, usually 100:1, and can reach up to 1000:1 at the maximum
Measuring flow velocity range: 0.1Nm/s to 100Nm/s
No pressure loss, suitable for pipes of any shape with a known cross-sectional area
Expert algorithms for the full measurement range, taking into account both small and large flow measurements
It adopts an insertable structure and can be installed and maintained online
Local display of instantaneous and cumulative flow rates, with alarm control
Technical parameters
Suitable diameters: DN15-3000
Measured medium: Various single or mixed gases, such as air, biogas, natural gas, nitrogen, etc
Accuracy: ± 1% reading ± 0.5% full scale
Repeatability: ± 0.15% full scale
Medium temperature: -10℃ to 120℃ (standard type S), 120℃ to 350℃ (High-temperature type HT)
Medium pressure: <2.0MPa
Probe material: 316L, HC, Ta, optional
Protection grade: IP65
Installation forms: Pipeline type, insertion type
Structural forms: integral type and split type
Explosion-proof type: Ordinary non-explosion-proof type, flameproof type (optional)
Ambient temperature: -30℃ to 70℃
Relative humidity: 5-90%
Power supply: 24VDC is standard, and 220V is also available
Signal output: 4 ~ 20mA, RS485