Gas microflow measurement device and method based on laser interferometry

Abstract

The invention discloses a gas microflow measurement device and method based on laser interferometry. The measurement device comprises a flowmeter vacuum device and a laser interferometer; a resonant cavity of the laser interferometer is communicated with a pressure stabilizing chamber of the flowmeter vacuum device, the standard flow value is obtained by means of the relationship between the frequency and gas microflow measured by the laser interferometer, and the relationship between the frequency and the gas microflow is obtained by means of a constant conductance method. The gas microflow measurement device and method have the advantages of high sensitivity, quick response, high resolution and the like, and reduction of the gas microflow measurement uncertainty to nearly 5 times is effectively achieved.

Description

technical field [0001] The invention relates to the technical field of vacuum standard leak calibration, in particular to a gas micro-flow measurement device and method based on laser interferometry. Background technique [0002] The document "'Calibration apparatus of vacuum leak by using constant conductance method' MAPAN Volume 22, 2007, Page 39-44" introduced the vacuum standard leak calibration based on the fixed conductance method gas micro-flowmeter established by China LIP The document proposes that by measuring the conductance value of the fixed conductance (molecular flow state) element in the gas microflowmeter, combined with the vacuum degree measured when the flowmeter is working, it can be realized (10 -8 ~10 -3 )Pam 3 / s standard gas flow. [0003] The advantage of this method is that it takes advantage of the stable geometric structure of the vacuum conductance element, the constant conductance corresponding to the molecular flow state, and the simple stru...

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Problems solved by technology

[0003] The advantage of this method is that it takes advantage of the stable geometric structure of the vacuum conductance element, the constant conductance corresponding to the molecular flow state, and the simple structure to obtain the standard gas flow rate. However, because the device uses a capacitive film vacuum gauge as the main standard , to measure the working pressure of the flowmeter, affected by factors such as the zero stability of the capacitive film vacuum gauge, thermal runaway effect, and diaphragm metal creep, the largest measurement uncertainty component of the flowmeter is introduced, resulting in the uncertainty of the flowmeter As high as 1.2%, the accuracy is not high, and it cannot meet the current situation that the demand for accurate traceability of vacuum values ​​is constantly increasing

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