The points need to be noticed when use thermal mass flow meter

2018-08-13

The points need to be noticed when use thermal mass flow meter


Thermal mass flow meter is a high-end measuring instrument with many advantages, wide range ratio, and insertion type for large caliber, 24 VDC or 220 VDC power supply, integral and separate type, but not its not applicable to all occasions.

Medium temperature

The thermal gas mass flow meter is designed based on the principle of thermal diffusion. The probe of the flow meter determines the heating temperature of the probe according to the temperature of the measured medium. Generally, the heating temperature of the probe is 50 higher than the temperature of the medium. It can be seen that the flow meter requires the measured medium temperature to be relatively constant during normal measurement, and the heating current is proportional to the medium flow rate.

Medium composition

The thermal gas mass flow meter can measure almost all single gas media (except acetylene), but in the actual measurement, many mixed gases need to be measured. When the thermal gas mass flow meter is selected, the mixed gas is required. All gas flow meters are marked with air as the measured medium, and the standard conversion factor can be found in a single medium. However, the mixed gas needs to convert the conversion coefficient according to the percentage of the measured medium component in the field time, but when the medium composition changes during the measurement, measurement error is increased.

Pressure

Thermal gas mass flow meters are not recommended for use under high pressure conditions. An important point of thermal measurement is the heat carried by the medium. When the pressure at the site is too high, the heat carried by the medium per unit volume is very large. Under the dual influence of the compression system and the reaction rate, the measured value of the flow meter will be It is less than the actual use, so it is recommended to the condition that the pressure is less than 4.0 Mpa.
 

High temperature

Measuring high temperature medium means that the temperature of the sensor is higher, and the power consumption of the whole circuit increases when the high temperature medium is measured. At present, the thermal gas mass flow meter can withstand high temperature to 450℃, which can meet most field requirements.

Q&T Instrument produces thermal gas mass flow meter. If contact us if you need.


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