Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

A dynamic gas-mixing system.

Authors
Carpenter-CR; Chilton-JE; Schnakenberg-GH Jr.
Source
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, IC 8934, 1983 Aug; :1-30
Link
NIOSHTIC No.
10003015
Abstract
A dynamic gas-mixing system assembled by the Bureau of Mines for the generation of precise gas mixtures from sources of concentrated or pure gases and diluent gases is described. A set of electronic mass flow controllers with maximum flows ranging from 10 to 5,000 ml/min, a so-called pure air generator, and gases in cylinders are used to generate differing gas concentrations. The repeatability of the delivery rate of a flow controller, measured on different days, has a precision of 0.3 pct of the setting. This dynamic gas-mixing system reduces the cylinder inventory and the demurrage charges for special gas mixtures. Gas mixtures that cannot be shipped commercially, such as flammable mixtures of methane in air, can be conveniently prepared by this system. The maximum dilution ratio is 2.5 X 10 4. Thus, gas mixtures can be made over a wide range of concentrations, from the percent region (by dilution of a pure single-component gas) to fractional parts per million (by dilution of a premixed standard, e.g., a 1,000-ppm mixture). This system is especially useful in determining the response of gas detection devices over the entire range of their measurement. Because the controllers are voltage controlled they lend themselves easily to automated control using computer-based systems.
Keywords
Mining-engineers; Chemical-dosimeters; Binary-systems-materials; Performance-evaluation; Design-criteria; Safety; Carbon-monoxide; Nitrogen-oxide-NO; Nitrogen-dioxide; Sulfur-dioxide; Hydrogen-sulfide; Oxygen; Methane; Carbon-dioxide; Automatic-control-equipment
Publication Date
19830801
Document Type
IH; Information Circular
Fiscal Year
1983
NTIS Accession No.
PB84-101450
NTIS Price
A03
Identifying No.
IC-8934
NIOSH Division
PRC
Source Name
Pittsburgh, PA: U.S. Department of the Interior, Bureau of Mines, IC 8934
State
PA
TOP