Abstract: Apparatus for monitoring and correcting gas analyzers having a measuring chamber with an inlet and an outlet, and a pump for supplying a pressurized measuring gas, further includes a flow throttle for providing flow resistance and being connected to the outlet of the analyzer to obtain a gas pressure in the chamber above a level downstream from the throttle; a pressure transducer is connected to measuring gas pressure of the measuring gas upstream from the throttle but downstream from the pump, preferably also upstream from the analyzer; an output signal from the transducer is used for correcting errors of the measuring signal of the gas analyzer caused by variations of gas pressure in the measuring chamber on account of variations in the gas pressure, for using the same output signal to extract a rate of flow indication as to the measuring gas and for ascertaining that the flow remains within specified limits.

Abstract: The photometer is calibrated by using a permanently built-in installation of four, similarly configured chambers in a good heat conducting carrier which is slidably interposed between sample and reference chambers on one hand and the detection structure on the other hand. One pair of these chambers is placed in the paths during measurement and is filled with inert gas, the other pair has one chamber filled with calibration gas, the other one with inert gas. All chambers are closed with similar windows.