Abstract: A method for the determination of gas concentrations xi in a gas mixture using a thermal conductivity detector with a Wheatstone bridge. It comprises the following method steps: measuring the bridge voltage Xa; correcting the measured values for the bridge voltage Xa, in particular with respect to drift; determination of the thermal conductivity of the gas mixture; and determination of at least one gas concentration xi. Preferably, an automatic zero-point correction and an automatic measuring range end value correction occur within the framework of the correction.

Abstract: The invention relates to an infrared gas sensor for determining the concentration of a measuring gas that absorbs infrared radiation, comprising a sensor housing containing two infrared radiation detectors adjacently situated on one end of a measurement beam path, and on the other end containing a measurement radiation source that emits infrared radiation. According to the invention, a measuring chamber accessible to the measuring gas is situated in the measurement beam path between the measurement radiation source and the detectors, at a distance from the detectors and sealed essentially gastight with respect to the remainder of the measurement beam path by at least one infrared-transmitting window.

Abstract: To create vortex flow sensors with an extended range of constant Strouhal number toward small Reynolds numbers, with a small variation of the vortex separation frequency, and with precise calculability of the Strouhal number in the range of a constant volumetric-flow-rate/vortex-separation-frequency ratio, a drag body is provided which is permanently connected with the internal wall of a fluid-conducting measuring tube of inside diameter D, or fixed in a frame set in the measuring tube, at diametrically opposed points, and which consists of an upstream-side flat trapezoidal part of length l.sub.1, of base width b.sub.1 on the upstream side, and of base width b.sub.2 on the downstream side, and a wake part adjoining the trapezoidal part without a gap and having a cross section in the form of a triangle of length l.sub.2 and base width b.sub.3. The following dimensioning equations hold:0.1.ltoreq.b.sub.1 /D.ltoreq.0.35;0.6.ltoreq.b.sub.2 /b.sub.1 .ltoreq.0.95;0.1.ltoreq.1.sub.1 /b.sub.1 .ltoreq.0.2;0.75.ltoreq.

Abstract: A radiating apparatus, particularly an infrared radiating apparatus, having at least one radiation source which has a configuration which is broad in the direction transverse to the emission direction of interest. In order to construct a radiating apparatus which persists over a relatively long period of time in being resistant to temperature changes and which has relatively low thermal inertia, a carbon strip is provided as a radiation source. The strip includes a plurality of segments which are joined together, the ends of which segments are mounted in support members, wherewith at least the first and last of said support members are in the form of respective contacts.