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Static expansion method vacuum standard based method for measuring minimum gas flow

A technology of static expansion and gas flow, which is applied to the volume/mass flow generated by mechanical effects, and the detection of fluid flow by measuring differential pressure. It can solve problems such as accurate measurement of limited pressure, improve measurement accuracy and avoid measurement uncertainty. Effect

Active Publication Date: 2011-12-07
NO 510 INST THE FIFTH RES INST OFCHINA AEROSPAE SCI & TECH
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Problems solved by technology

The transfer coefficient of the magnetic levitation rotor gauge will change with time, gas type and temperature. Capacitance film gauge has thermal runaway effect under low pressure. Uncertainty factor

Method used

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  • Static expansion method vacuum standard based method for measuring minimum gas flow
  • Static expansion method vacuum standard based method for measuring minimum gas flow

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Embodiment Construction

[0026] like figure 1 As shown, it is the extremely small gas flow measuring device based on the vacuum standard of the static expansion method of the present invention, which consists of a pre-stage pressure measurement system 1, a valve one 2, a gas pressure attenuation system 3, a valve two 4, a calibration chamber 5, and a valve three 6 , small hole 7, valve four 8, valve five 9, getter pump 10, valve six 11, molecular pump 12, backing pump 13 and ionization gauge 14.

[0027] The pre-stage pressure measurement system 1 is connected to the gas pressure attenuation system 3 through the valve one 2, the gas pressure attenuation system 3 is connected to the calibration chamber 5 through the valve two 4, the small hole 7 is connected in parallel with the valve four 8, and one end passes through the valve three 6 and the calibration chamber 5, one end is connected to the vacuum system, the getter pump 10 is connected to the calibration chamber 5 through the valve five 9, the for...

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Abstract

The invention relates to a static expansion method vacuum standard based method for measuring minimum gas flow, which comprises the following steps of: 1, exhausting a calibration chamber and a connecting vacuum pipe; 2, roasting the whole device for degassing; 3, controlling the inside of the calibration chamber to reach an ultimate vacuum of 10<-9> Pa in magnitude; 4, slowly raising the pressure inside the calibration chamber; 5, charging a high-purity gas with a certain pressure for the front stage of the static expansion method vacuum standard; 6, introducing the gas inside the calibration chamber into a vacuum system through a small hole; and 7, attenuating the pressure in the system according to the conductance of the small hole and the gas pressure to obtain gas flow. The gas pressure generated by using the static expansion method vacuum standard is used to replace the charged gas pressure of a fixed conductance method gas flow meter, and thus the method avoids using a capacitance film gauge or magnetic suspension rotor gauge to measure the pressure, thereby further improving the measurement accuracy of the gas flow.

Description

technical field [0001] The invention relates to a device and method for measuring extremely small gas flow, in particular to a device and method for measuring extremely small gas flow based on a vacuum standard of static expansion method. Background technique [0002] In metrology laboratories, high-precision gas micro-flow meters are mostly used to measure and provide known gas flow rates. [0003] The document "Li Detian. Review of gas micro-flow metering at the German Federal Institute of Physics and Technology (PTB). Journal of Vacuum Science and Technology 23 (4), 2003." introduces the gas flowmeter of German PTB, which is currently at the highest international level. The gas flowmeter developed by PTB works in three different modes: when the flow rate is in the range of (10-8~10-4) Pa.m3 / s, use the constant pressure method; when the flow rate is less than 10-8Pa.m3 / s, use the fixed pressure method Conductance method; when the flow rate is greater than 10-4Pa.m3 / s, use...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01F1/34
Inventor 李得天成永军冯焱徐婕郭美如
Owner NO 510 INST THE FIFTH RES INST OFCHINA AEROSPAE SCI & TECH
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