| 摘要 |
The device described is intended preferably for feeding air into the cabins of motor vehicles or personal protection cabins and involves the use of one or several semiconductor gas sensors detecting pollutants. These known semiconductor gas sensors present, in particular in the case of the use of a motor vehicle, the disadvantage that they have too high a transverse sensitivity to different operating speeds, temperatures, air humidity values etc.. In order to avoid these disadvantages, the invention proposes that the gas flows to be evaluated are fed in an alternating manner into a gas detector (4). The latter is placed at the separation point between the outside air and the air of the cabin, and switching, which is effected in a few seconds, enables a practically constant comparison to be made between the quality of the inside and outside air. For this purpose, a switching system is associated with the gas detector (4) and both may be fixed to a fresh air/ambient air valve (3). The output signal of the gas detector (4) serves to control said valve (3). |
