Abstract: A measuring device for determining the concentrations of gases by radiation absorption. The device includes at least one radiation source for generating radiation, a measuring cell, which is arranged downstream of the radiation source and in which the medium to be measured is located and at least one radiation detector, which is reached by the radiation after it has been sent through the measuring cell. A radiation guide device is provided by which the radiation is guided to the radiation detector. The radiation guide device includes a main optical unit, which has, on the one hand, an optical element (4), so that the punctiform radiation source is imaged in a bar-shaped radiation spot (5) extending along a preferred direction (1), and which has, on the other hand, parallel reflection surfaces (7, 7?), which extend at right angles to the preferred direction and at the inner surfaces of which the radiation is totally reflected between the optical element (4) and the radiation detector (3, 3?).

Abstract: A gas sensor is provided that is delimited from the environment with a preferably replaceable cap (8) made of a porous, gas-permeable and water-impermeable material, especially sintered PTFE. The gas sensor is protected against environmental moisture and can be permanently provided with the cap (8) and with a special calibrating adapter (9) both during the gas measurement and during the necessary calibration. Due to the special design of the cap (8) and the calibrating adapter (9), the gas sensor offers the possibility of remote calibration, which can be carried out with high accuracy and is independent from weather effects, especially wind.

Abstract: A measuring device for determining the concentrations of gases by radiation absorption. The device includes at least one radiation source for generating radiation, a measuring cell, which is arranged downstream of the radiation source and in which the medium to be measured is located and at least one radiation detector, which is reached by the radiation after it has been sent through the measuring cell. A radiation guide device is provided by which the radiation is guided to the radiation detector. The radiation guide device includes a main optical unit, which has, on the one hand, an optical element (4), so that the punctiform radiation source is imaged in a bar-shaped radiation spot (5) extending along a preferred direction (1), and which has, on the other hand, parallel reflection surfaces (7, 7?), which extend at right angles to the preferred direction and at the inner surfaces of which the radiation is totally reflected between the optical element (4) and the radiation detector (3, 3?).

Abstract: An explosion-proof gas sensor has a measuring element (2), which generates a measured signal that depends on the concentration of the measured gas and is delimited against the environment by means of a porous, gas-permeable and sintered metal body (7). The sintered metal body (7) has a high mechanical stability, so that the use of additional components, which hinder the diffusion of the gas to be measured into the gas sensor and thus prolong the response time of the gas sensor, can be eliminated.

Abstract: A gas sensor is provided that is delimited from the environment with a preferably replaceable cap (8) made of a porous, gas-permeable and water-impermeable material, especially sintered PTFE. The gas sensor is protected against environmental moisture and can be permanently provided with the cap (8) and with a special calibrating adapter (9) both during the gas measurement and during the necessary calibration. Due to the special design of the cap (8) and the calibrating adapter (9), the gas sensor offers the possibility of remote calibration, which can be carried out with high accuracy and is independent from weather effects, especially wind.

Abstract: An explosion-proof gas sensor has a measuring element (2), which generates a measured signal that depends on the concentration of the measured gas and is delimited against the environment by means of a porous, gas-permeable and sintered metal body (7). The sintered metal body (7) has a high mechanical stability, so that the use of additional components, which hinder the diffusion of the gas to be measured into the gas sensor and thus prolong the response time of the gas sensor, can be eliminated.