SENSOR APPARATUS FOR EXAMINING A SAMPLE GAS VOLUME

Abstract

A sensor apparatus for examining a sample gas volume, particularly for capturing the particulate matter content of a sample gas volume, includes at least one measuring chamber to accommodate the sample gas that is to be analysed, and at least one sample gas feed allocated to the measuring chamber and with at least one sample gas discharge allocated to the measuring chamber, in which it is provided as essential for the invention that at least one cleaning gas feed is allocated to the measuring chamber, that the cleaning gas feed is connected to the measuring chamber via at least one cleaning gas inlet, that a condensation area is allocated to the cleaning gas feed, and that the condensation area is arranged in front of the cleaning gas inlet of the cleaning gas feed into the measuring chamber.

Claims

1. A sensor apparatus for examining a sample gas volume, particularly for capturing the particulate matter content of a sample gas volume, with at least one measuring chamber for accommodating the sample gas to be examined, with at least one sample gas feed allocated allocated to the measuring chamber and with at least one sample gas discharge allocated to the measuring chamber, wherein at least one cleaning gas feed is allocated to the measuring chamber, the cleaning gas feed is connected to the measuring chamber via at least one cleaning gas inlet, a condensation area is allocated to the cleaning gas feed, and the condensation area is arranged before the cleaning gas inlet of the cleaning gas feed in the measuring chamber.

2. The sensor apparatus according to claim 1, wherein at least one filtering device is allocated to the cleaning gas feed for purifying the gas that is directed through the cleaning gas feed, that the filtering device has a filter housing and at least one flat filter, and that the condensation area is arranged inside the filter housing.

3. The sensor apparatus according to claim 2, wherein the condensation area is designed as a condensation surface, wherein the condensation surface is embodied as an interior wall of the filter housing.

4. The sensor apparatus according to claim 2, wherein at least a first wall of the filter housing includes at least one gas feed line to the measuring chamber, at least one second wall of the filter housing has at least one inlet of the cleaning gas feed, at least one filter is arranged between the first and the second walls, and the condensation surface is separated from the gas feed line to the measuring chamber the filter.

5. The sensor apparatus according to claim 2, wherein the flat filter slopes downwards from the inlet of the cleaning gas feed to the filter housing relative to the condensation surface.

6. The sensor apparatus according to claim 2, wherein at least one filter is designed to be permeable to gas and impermeable to liquid.

7. The sensor apparatus according to claim 2, wherein the condensation surface is arranged on the side of the filter housing facing away from the measuring chamber.

8. The sensor apparatus according to claim 1, wherein at least one cleaning gas inlet in such a way that the cleaning gas stream is directed between the sample gas stream and the optical elements arranged in the measuring chamber.

9. A vehicle having a sensor apparatus according to claim 1, wherein the vehicle is equipped with an air conditioning system for regulating the atmosphere in the vehicle interior, wherein the sensor apparatus has at least one measuring chamber for accommodating a sample gas to be examined, at least one sample gas feed allocated to the measuring chamber, and at least one sample gas discharge allocated to the measuring chamber, wherein the sensor apparatus has a condensation surface and the condensation surface is arranged in the area of the air-conditioned interior.

10. The vehicle according to claim 9, wherein the sensor apparatus has a filtering device with a filter housing, the condensation surface is embodied as an interior wall of the filter housing, and the outer wall of the filter housing corresponding to the interior wall is arranged to face the air-conditioned interior of the vehicle.

11. The vehicle according to claim 9, wherein the measuring chamber of the sensor apparatus is arranged to face away from the air-conditioned interior of the vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In the following text, the invention will be explained in greater detail with reference to an example thereof illustrated in the drawing. In detail, the drawing shows:

[0020] The FIGURE is a schematic representation of a sensor apparatus with a measuring chamber, a ventilation system and a filter housing.

DETAILED DESCRIPTION

[0021] The FIGURE represents a sensor apparatus 1 having a measuring chamber 2, a sample gas feed 3, a sample gas discharge 4 and a ventilation system 5. A sample gas volume to be examined, for example a sample gas volume from the atmosphere surrounding a motor vehicle, is fed to the measuring chamber 2 via the sample gas feed 3. A measuring device with a laser light source and optical components is allocated to the measuring chamber 2 for examining the sample gas volume. After the examination, the sample gas volume is directed out of the measuring chamber 2 vis the sample gas discharge 4. For this purpose, the sensor apparatus 1 includes a ventilation system 5, via which the sample gas volume, in the form of a sample gas stream, is directed through the measuring chamber 2. The sample gas discharge 3 has a connection with a cleaning gas feed 6 which is arranged in front of the ventilation system 5 from the perspective of the measuring chamber 2. A fraction of the previously examined sample gas volume is diverted from the sample gas discharge 4 into the cleaning gas feed 6 and fed to a filter housing 7. A flat filter 8, for example a filter made of nonwoven material, is arranged in the filter housing 7. The sample gas diverted from the sample gas discharge 4 through the cleaning gas feed 6 is purified by the filter 8 in the filter housing 7 by precipitation of particles present in the sample gas volume. The filter housing 7 includes a gas feed line 9 to the measuring chamber 2, through which the purified sample gas may be directed to the measuring chamber 2 as cleaning gas. The filter 8 is arranged inside the filter housing 7 in such a way that the gas volume which is fed to the filter housing 7 must pass through the filter 8 before entering the measuring chamber 2. The gas feed line 9 to the measuring chamber 2 is separated from the inlet of the cleaning gas feed 6 into the filter housing 7 by the filter 8. The condensation surface 10 is arranged in the area of the inlet of the cleaning gas feed 6 into the filter housing 7. The condensation area 10 is embodied as an interior wall of the filter housing 7. In particular, the filter housing 7 of the sensor apparatus 1 may be arranged in the interior of a motor vehicle in such manner that the condensation surface 10 of the filter housing 7 and the corresponding outer wall faces towards the air-conditioned interior of the vehicle, while the measuring chamber 2, the sample gas feed 3 and the sample gas discharge 4 face away from the air-conditioned interior of the vehicle. In the area of the measuring chamber 2, the sample gas feed 3 and the sample gas discharge 4, the ventilation unit 5 and the operation of the measuring device allocated to the measuring chamber 2 result in the radiation of inherent heat, with the result that in this area a higher temperature prevails than in the area of the condensation surface 10. This favours condensation of atmospheric moisture which is present in the sample gas volume in the area of the condensation surface 10. The flat filter 8 is arranged in the filter housing 7 at an angle to the condensation surface 10. In particular, the filter 8 may slope from downwards from the inlet of the cleaning gas feed 6 into the filter housing 7 relative to the condensation surface 10. Thus, the distance between the filter 8 and the condensation surface 10 is greater in the area of the inlet than in the area farther from the inlet. The sloping arrangement of the filter 8 means that there is more room available for collecting the condensed liquid in the area of the gas inlet.

[0022] All features presented in the preceding description and in the claims can be combined in any permutation with the features of the independent claims. The disclosure of the invention is thus not limited to the feature combinations that are described and claimed, but rather all feature combinations that a practicable within the scope of the invention are to be considered disclosed.