1) The main characteristics of a thermal distributed mass flowmeter are: direct measurement of mass flow without temperature and pressure compensation; Non contact, no moving parts, no flow barriers, low pressure loss, high reliability; Can measure low flow rate and small gas flow rate, as low as 5mL/min (standard state); Require the gas medium to be dry and clean, free of moisture, oil, and other impurities; The shunt type can obtain linear characteristics and can be used to measure large and medium pressure flow rates. When using it, the shunt temperature should be ensured; Slow dynamic response, with a time constant of about 5 seconds.
2) The main features of immersion thermal mass flowmeter are: direct measurement of mass flow without temperature and pressure compensation; No moving parts, high reliability; Suitable for measuring large-diameter, non-circular cross-section pipelines, and narrow on-site spaces (insert type); As a platinum resistance sensor with a stainless steel casing, it is insensitive to dust, solid particles, oil, and moisture in other components. Plug in type can be continuously removed for maintenance and replacement. Can be used for measuring dirty fluids.
Precautions for installation and use of thermal gas mass flowmeter
1) In terms of installation posture, most thermal distributed mass flow meters can be installed in any posture (horizontal, vertical, or inclined), as long as the electrical zero point is adjusted under working conditions such as pressure and temperature after installation. However, some instruments are sensitive to installation posture and must be strictly followed according to the instructions. The performance of most immersed thermal mass flow meters is not affected by installation posture, but it is necessary to strictly follow the instructions at low flow rates.
2) In terms of the front straight pipe section, thermal distribution is not sensitive, while immersion flow sensors and plug-in instruments with measuring tubes require a certain length of front straight pipe section, which should be installed according to the manufacturer's recommendations.
3) The vibration of the pipeline connecting the thermal mass flowmeter within the common range will not cause vibration interference; The detection rod of the plug-in thermal mass flowmeter must be fixed to the pipeline and avoid vibration areas.
4) Thermal mass flow meters have a long response time and are not suitable for pulsating flow.
