Abstract: A breathing apparatus with a display unit for the transmission of measured data via a display field of the display unit into the field of vision of a person wearing the unit. The readability of the measured data displayed is improved in daylight with simultaneously reduced energy demand. The display field includes an LC display, which is at least transparent for transmission radiation. An optical concentrator is provided, which collects the ambient light via a light entering surface and emits the collected light via a light exiting surface.

Abstract: The invention is directed to an apparatus for determining the proportion of substances having paramagnetic characteristics, such as oxygen, in a mixture of substances. The apparatus has a housing and the mixture of substances is passed along an arrangement of four magnetic field sources by a rotatable cuvette arrangement mounted in the housing. The apparatus is improved in that the effect of external disturbing influences on the penetration of the cuvette by the magnetic field is reduced and so that the measuring characteristics are independent of the position of the plurality of magnetic field generating units. For this purpose, the arrangement of the magnetic field sources is simply disposed at one side of the housing lying opposite to the rotating surface of the cuvette arrangement facing toward the drive shaft. The arrangement of magnetic field sources includes a carrier plate on which the magnetic field sources are accommodated and carry respective measuring field coils.

Abstract: A method detects the proportion of combustible gas in a mixture of air with a measuring device which operates by both the heat-tone and heat-conductivity methods. The method permits measurement in the full concentration range with a high degree of accuracy and the lowest possible energy consumption. The measuring device is made small and light and its sensor has a long service life. The method uses one single sensor which operates at a low temperature in the heat-conductivity mode or alternatively, catalytically active at a higher temperature in the heat-tone mode. If the measurement provides a result below a reference value or within a reference value window, measurement continues in the more accurate heat-tone mode. When the gas concentration increases during measurement, in order to avoid ambiguity of the measuring signal and damage to the sensor above a load-limit value, measurement again takes place in the heat-conductivity mode by reducing the temperature of the sensor.