Model 921A Combustible Gas Meter
The Model 921A Combustible Gas Meter passes a sample of the unknown gas over a heated catalytic sensor along with instrument air to provide oxygen. The heat of oxidation of any combustible gases present is measured, and the meter automatically converts and displays the result directly in percent TCG.
Prior to making a series of measurements, a field calibration is performed using the supplied cylinders of Zero Nitrogen and 1% Methane calibration gases. This compensates for normal sensitivity variations due to sensor aging, gas impurities, environmental conditions, or other causes.
After initial field calibration is completed, TCG measurements are virtually automatic. The instrument air cylinder is left connected to the Model 921A, and the gas sampling port of the transformer is connected to the TCG input port using the supplied sampling hose and oil filter assembly. When the TCG key is pressed, the measurement cycle begins. The entire measurement cycle takes less than 45 seconds.
Arbiter Systems, Inc., 1324 Vendels Circle, #121, Paso Robles, CA 93446. Tel: 805-237-3831; Fax: 805-238-5717.