| 摘要 |
A gas sensor instrument, such as for detecting radon gas, comprises a housing formed of two parts 102, 104 and a diffusion chamber inside the housing. The diffusion chamber is formed from two parts, at least one of which 106 is formed integrally with one of the housing parts. This allows a reduction in size of the instrument without compromising the size of the diffusion chamber. One of the diffusion chamber parts may be arranged to overlap with the other to create a diffusion path through which gas enters the chamber and the inner surfaces and rim of the chamber may be electrically conducting to form a Faraday cage. Also disclosed is an instrument housing comprising a tubular projection formed integrally with one of the housing parts that forms part of a Faraday cage to surround an electrical component of the instrument located on a printed circuit board. |
