Method for measuring volume change of volume-changeable chamber bellows of constant pressure type gas flow meter

Abstract

The invention discloses a method for measuring volume change of a constant pressure gas flowmeter bellows, belonging to the technical field of vacuum measurement; by adopting the isothermal expansion principle of gas, the method comprises the following steps: firstly filling gas with known pressure into a variable capacitance chamber; filling the gas into a standard container to measure the volume of the variable capacitance chamber when the bellows is in a natural state; then filling the gas into the bellows in natural state in the variable capacitance chamber and compressing the bellows to change the volume of the bellows and increase the pressure in the variable capacitance chamber to finally measure the volume change of the bellows. The method avoids using water medium for measurement, as well as such processing as degasing, baking and the like after the measurement but before the use of the variable capacitance chamber and bellows. The measuring process is simple and easy, dismounting of the variable capacitance chamber is avoided, thus being favorable for the protection and maintenance of vacuum systems; the measuring period is short, gas leakage and escape are reduced by removing the dynamic tight connecting properties of pistons and oil chambers, thus being conductive to the improvement of measuring accuracy.

Description

Technical field [0001] The present invention involves a measurement method for the volume change of a constant -voltage gas flow meter ripple, which belongs to the field of vacuum measurement technology. Background technique [0002] In the literature "German Federal Physics and Technology Research Institute (PTB) gas micro -flow measurement," Vacuum Science and Technology ", No. 4, 2003, p. 289 to 294" introduced a PTB constant voltage gas flowMethod of the volume variation of the volume of the corpus room.This method is the measuring method. The method is as follows: After the ripple components are pulled vacuum, it is filled with 4 distilled and qi water, and the ripple component is connected to a container placed on a sensitive balance with a thin tube.When the ripples are compressed, the water is squeezed into the container. After correcting the buoyancy and evaporation of the water, the volume change of the ripple tube is obtained by measuring the quality and density of th...

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Problems solved by technology

[0003]The disadvantage of this method is that during the measurement process, it cannot be calibrated at the original position, and the variable volume chamber needs to be removed from the vacuum device, so that the vacuum system is exposed to Atmospheric, not conducive to the maintenance of the vacuum system

Secondly, water medium is required for measurement, and the corrugated pipe needs to be processed before it can be reused, which may cause changes between the measured value and the actual use value

Thirdly, the measurement process is complicated and the measurement time period is long. PTB has only conducted 3 measurements in 17 years

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