Abstract: A nondispersive, two-beam, infrared gas analyzer with two differently long measuring gas cells and differential detectors is improved by gilt detection cell interiors and absorbing rods in the detector cell which is in line with the shorter measuring gas cell. Adjustable absorption permits suppression of cross sensitivity errors.

Abstract: The chopped infrared radiation leaving a measuring and sample gas chamber in an infrared gas analyzer is passed through and into two serially arranged detection chambers which are connected to a differential pressure chamber with capacitive pickup. The chambers are filled with gas of the type whose concentration, in the sample gas, is to be detected. One of the detector chambers contains a thin black wire, a diaphragm on the outside may shield an adjustable portion of that wire from radiation. The wire absorbs all radiation it intercepts and heats the environment.

Abstract: The cross sensitivity of a two-beam infrared gas analyzer is eliminated by using two differently long cells for the measuring gas in the two beam paths and by using an interference filter at least in the beam path containing the longer cell; the filter, however, does not filter the entire beam in that path.

Abstract: The cross-sensitivity of a two-beam infrared gas analyzer is reduced by using two differently long cells for the sample gas in the two beam paths. The path with the short sample gas cell is intercepted by a detector cell having highly absorbing wall while the detector cell in the other path is highly reflective, e.g., made of gold. The two detector cells are interconnected by a differential pressure chamber with capacitive pickup.

Abstract: The sensitivity and selectivity of a two beam analyzer operating with negative filtering and differential absorption-pressure detection is improved by employing differently long cells for the sample gas in the two beam paths, which reduces the effect resulting from overlapping absorption bands of the wanted and of unwanted components in the sample gas.