Abstract: In a two-beam gas analyzer, a measurement beam passes through a measurement cuvette filled with a measurement gas, and a comparison beam passes through a comparison cuvette filled with a comparison gas. Using a detector arrangement, a difference signal is generated from the beams exiting from the two cuvettes resulting in a measurement value which corresponds to the measurement gas concentration when weighted with a weighting factor. To allow recalibration after a calibration of the two-beam gas analyzer with calibration gas and adjustment of the weighting factor to a value which results in the appropriate calibration value as the measurement value, without having to fill the measurement cuvette with a calibration gas, an additional factor is determined when the measurement cuvette is not filled or is filled with inert gas. Thus, the difference signal corresponds to the calibration value when weighted with the weighting factor and the additional factor.

Abstract: Two gas-filled chambers (K1, K2) arranged one behind the other in the beam path, with frontal areas (F) transparent to the beam, are interconnected by a first line (L12) which contains a first pressure or flow rate sensor (SF1). A buffer space (P) is connected to one of the two chambers (K1) via a second line (L11) in which is arranged a second pressure or flow rate sensor (SF2). The output signals from both flow rate sensors (SF1, SF2) are taken via amplifiers (V1, V2) to a differentiator. The degree of amplification of at least one amplifier (V2) is tunable for equalizing. The field of application of the invention is in gas analyzers operating on the infrared absorption system.

Abstract: A pneumatic detector for nondispersive infrared gas analyzers comprises two gas-filled chambers disposable one behind the colinearly with a source of infrared radiation and connected to one another by a gas conductive line containing a microflow sensor which generates an electrical signal indicative of the pressure difference between the two chambers. A third chamber is disposed on a side of the two chambers opposite the radiation source and is connected to a second of the two chambers via a gas conductive line. An adjustable aperture stop is arranged between the second and the third gas-filled chambers. The arrangement of chambers and the adjustable aperture stop serve to compensate and reduce to zero a negative cross-sensitivity.

Abstract: A nondispersive infrared gas analyzer of the type wherein gas-filled chambers are arranged in the path of modulated infrared radiation. A measurement pickup is provided for producing a signal responsive to the response of a gas contained in the chamber to the infrared radiation. The infrared radiation is produced by a source of infrared radiation which is powered by a pulsed energy supply, the pulsed energy supply being responsive to control signals so as to provide pulses which have a duty cycle which is less than 1, and preferably between 0.1 and 0.5. The duration of the pulses is controlled in response to the maximum value of a measuring signal of an output of a measuring pickup. In other embodiments, the duration of the pulses may be determined empirically, by calculation, or by means of peak detector. This arrangement provides almost 100% modulation while considerably reducing power consumption and without loss of sensitivity.