SU1709203A1 - Method for measuring helium concentration in gas mixtures - Google Patents

Abstract

The invention relates to the analysis of gaseous media and can be used to control the tightness of various volumes in scientific studies and under production conditions. The purpose of the invention is to improve the accuracy of measuring the concentration of gels in gas mixtures and to simplify the measurement method. The goal is achieved by using pure gels as a comparison sample and using membranes selectively permeable to gels to inject the comparison sample and the analyzed mixture.

Description

The invention relates to mass spectrometry 1 can be applied to determine the content of gels in gas mixtures.

The aim of the invention is to simplify the technology of controlling the concentration of gels and improving the accuracy of measurements.

This goal is achieved by that pure helium, which is always in the workplace, is used as the reference mixture. The leak of the tested mixture and pure helium in the leak detector is made through separate leak leaks selectively permeable to helium, thus selecting such a ratio of throughput so that it does not differ from the ratio of pure helium to the measured concentration by more than 2 times.

This makes it possible to measure the concentration with the reading of the leak detector within one scale range, which provides the necessary measurement accuracy (when using different scale ranges in the measurement process, the accuracy is reduced due to the inherent leakage of the leak detector in different ranges.

Equal pressures in the mass spectrometry chamber are provided automatically, since the inlet of the pure gel and the tested mixture into the leak detector is performed at atmospheric pressure through a fluoroplastic film of the type F4MB. which is virtually impermeable to all gases except gels.

The method is carried out as follows.

The leak gels for pure gels and provable mixed mixture are purged with air and the zero signal of the Ryu leak detector is fixed. After this, for 50-60 seconds, a leaker with lower permeability is blown with pure helium with an excess pressure of 0.05 to 0.1 kgf / cm. After 5 to 10 seconds after purging, a signal is recorded to pure helium one. This air leak is blown again for 1 to 2 minutes and the zero signal ao is fixed. Thereafter, for another 50–60 seconds, another leakage of the tested mixture with a pressure of 0.05-10%, 1 kgf / cm is blown through.

and through S - 10 sec the signal of leakage detector CGH is fixed.

Determined concentration 1 is calculated from 6prvlyly

C - and Dx-az1

  ane-o);

where a is the coefficient depending on the throughput capabilities of the leak.

This coefficient is determined in the process of the preliminary 8 calibrating of one product from the batch by feeding known reference mixtures and pure gel,

The proposed method allows for the prompt and simple monitoring of concentrated / iM gels 0 mixtures with a measuring accuracy of no worse than + 10% under the production conditions.

The method can be implemented with the inlet of the mixtures and the aerator and in the form of a fluoroplastic film E-F4MB with a thickness of 100 microns with the following area (flow area for (0.64-2.2)% - (Bor + 635) mm for (2.2-8)% - ( 160 -t-175} mm-, for (8-30)% - (45 47, 5) mm, while the leakage area of pure gel is 7 mm,

The economic effect of the use of a medium .1st method is created for

by reducing the laboriousness of the process of measuring the concentration of gels, due to the elimination of work on the preparation of standard mixtures and their placement at production sites, as well as by reducing the cost of re-testing of products, due to an increase in the ACCURACY 11 measurement of the concentration of gels in the working mixtures.

Claims (1)

Invention Formula The method of ireni concentration of gels in gas by alternating inlet of tested mixtures of sample of comparison in mass spectrometer, comparison of indications, is characterized by the fact that, in order to simplify the method of increasing the accuracy of measurements, pure reference helium is used as reference sample gases and a mass spectrometer are carried out through selective elements permeable to helium with different capacities, and the gas flows through them are set with a ratio different from the ratio of the measured concentration and Mstogb gels no more than twice.