Method for temperature drift inhibition of constant power type thermal type gas flowmeter

Abstract

The invention discloses a method for temperature drift inhibition of a constant power type thermal type gas flowmeter. The method comprises the steps of recording an environment temperature value of a laboratory during verification by a lower thermal type gas flowmeter; recording an environment temperature value of a use site of the lower thermal type gas flowmeter and making a comparison with the environment temperature value of the laboratory to obtain a temperature difference; analyzing a medium specific heat capacity coefficient according to a corresponding medium, obtaining a temperature compensation coefficient by calculation, and obtaining an initialization deviation by measurement; obtaining a compensation value by calculating the obtained medium specific heat capacity coefficient, the temperature compensation coefficient and the initialization deviation; and adding the compensation value obtained by calculation and an actual measured value to obtain an accurately corrected measured value. The compensation is performed through the compensation method, zero drift caused by the difference between verification temperature and the actual product environment can be inhibited well, temperature compensation is performed on the flowmeter effectively, zero drift is inhibited, and product measurement precision and stability are improved.

Description

technical field [0001] The invention belongs to the field of flow detection, in particular to a method for suppressing temperature drift of a constant power type thermal gas flowmeter. Background technique [0002] Common thermal flowmeter probes have two platinum resistors, one is heated as an active element (speed probe), and the other is not heated as a reference element (temperature probe). According to the principle of thermodynamics, the power provided to the heating probe is equal to the energy taken away by the convective heat transfer of the flowing gas. which is: [0003] I w 2 R w =hAs(T w -T f ) [0004] where I w is the current through the heating probe, R w is the resistance of the heating probe, h is the surface heat transfer coefficient, As is the surface area of ​​the probe, Tw is the temperature of the heating probe, T f is the gas temperature measured by the temperature probe. [0005] hAs can be expressed as follows: [0006] hAs=A+B*q m 1 / 2...

AI Technical Summary

Problems solved by technology

The reason for this kind of error is that the actual calibration process of the constant power measuring thermal flowmeter is calibrated according to the temperature of the laboratory, but the actual ambient temperature used on site will definitely be different from the ambient temperature during calibration. , resulting in zero drift and an increase in measurement error

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