Test gas

from Wikipedia, the free encyclopedia

A test gas is a gas mixture that is used to check measuring and analysis devices. Numerous test gases can be obtained from retailers.

definition

A test gas usually consists of a base gas and one or more admixtures. The base gas in turn can be a pure gas or a gas mixture.

The term calibration gas is often used synonymously in questions of calibration .

A base gas that does not contain any admixtures is called zero gas.

Manufacturing

Air or nitrogen are usually used as the base gas for the production of test gases . To this is added a known amount of a component of interest.

Test gases can be produced using different processes. A distinction is made between static and dynamic processes. With static processes, volumes are mixed with one another, with dynamic processes, volume flows. Devices for the dynamic production of test gases are called test gas generators.

The following manufacturing processes have established themselves, among others:

  • Gravimetric method : Weighing a closed container before and after the admission of gas
  • Dynamic production with gas mixing pumps: suction of two gases through mutual cooperation of metering pumps
  • Production by injection : injection of an admixture into a basic gas stream; the injection can be continuous or periodic.
  • Production by permeation of the admixture : Permeation of the admixture through a suitable membrane into a basic gas flow
  • Production using manometric methods : Successive filling of an evacuated pressure vessel with basic gas and admixtures and subsequent pressure measurement

The selection of the manufacturing process depends, among other things, on the properties of the admixtures, the desired pressure of the test gas and the desired concentration of the admixture. Concentrations are given as mass per volume, amount of substance per volume, mass content, volume content or amount of substance.

Many test gases can be obtained from retailers in pressurized gas cylinders.

use

Test gases are used to calibrate gas measuring devices and gas warning devices , which is why compliance with the defined concentration , substance proportions or volume proportions is particularly important in the production of test gases.

In round robin tests , test gases are used for quality control of measuring points.

literature

  • VDI 3490 Part 2: 1980-12 Measurement of gases; Test gases; Production method; Overview. VDI publishing house, Düsseldorf.

Individual evidence

  1. ↑ a b c VDI 3490 sheet 1: 1980-12 measurement of gases; Test gases; Terms and explanations. VDI-Verlag, Düsseldorf, p. 2.
  2. ↑ a b c d Franz Joseph Dreyhaupt (Ed.): VDI-Lexikon Umwelttechnik. VDI-Verlag Düsseldorf, 1994, ISBN 3-18-400891-6 , pp. 942-943.
  3. ↑ VDI 2100 sheet 1: 2008-06 Measurement of gaseous compounds in the outside air; Measuring indoor air pollution; Gas chromatographic determination of organic compounds; Basics (Gaseous ambient air pollution measurement; Indoor air pollution measurement; Gas chromatographic determination of organic compounds; Fundamentals). Beuth Verlag, Berlin, p. 43.
  4. ^ Günter Baumbach: Air pollution control . Springer-Verlag Berlin, Heidelberg, New York, 2nd edition 1992, ISBN 3-540-55078-X , p. 241.
  5. ↑ a b VDI 3490 sheet 2: 1980-12 measurement of gases; Test gases; Production method; Overview. VDI-Verlag, Düsseldorf, p. 2.
  6. ↑ VDI 3490 sheet 4: 1980-12 measurement of gases; Test gases; Manufactured using gravimetric methods. VDI-Verlag, Düsseldorf, p. 2.
  7. ↑ VDI 3490 sheet 6: 1988-12 measurement of gases; Test gases; Dynamic production with gas mixing pumps. Beuth Verlag, Berlin, p. 2.
  8. ↑ VDI 3490 sheet 8: 1981-01 Measurement of gases; Test gases; Manufactured by continuous injection. VDI-Verlag, Düsseldorf, p. 2.
  9. ↑ VDI 3490 sheet 7: 1980-12 measurement of gases; Test gases; Dynamic production through periodic injection. VDI-Verlag, Düsseldorf, p. 2.
  10. ↑ VDI 3490 sheet 9: 1980-12 measurement of gases; Test gases; Production by permeation of the admixture into a basic gas flow. VDI-Verlag, Düsseldorf, p. 1.
  11. ↑ VDI 3490 sheet 12: 1988-12 measurement of gases; Test gases; Production of test gases by manometric methods. Beuth Verlag, Berlin, p. 2.
  12. ↑ Franziska Raschick, Christian Monsé, Krista Gusbeth, Brigitte Maybaum, Yvonne Giesen, Dietmar Breuer, Christian Monz: Ring tests for internal and external measuring points on the test gas line of the Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA). In: Hazardous substances - cleanliness. Air . 76, No. 3, 2016, ISSN  0949-8036 , pp. 78-84.