| 摘要 |
PURPOSE:To prevent corrosion of metallic parts, by allowing a specimen gas to pass through a ferric hydroxide contained eliminating layer arranged in such a way that it embraces a gas sensor. CONSTITUTION:A specimen gas containing combustible gas and hydrogen sulphide in common, after natural diffusion, arrives at a gas sensor 10 through penetrating hole 13, eliminating layer 14, and inside cover 11. At this moment, hydrogen sulphide gas in the specimen gas reacts with Ferric hydroxide in the eliminating layer 14 to be removed. As a result, even if a catalyst of platinum nature is used as a gas detecting element 6, no deterioration of its catalyst function is caused and no corrosion of the such metallic parts as stays 4, 5, partitions 8, etc. are observed. And, when the combustible gas in the specimen gas contacts the element 6, it burns on the surface of the element 6, causing thus heating of the element 6 and increase of its resistance. On the other hand, as the combustible gas does not burn on a compensating element 7, its resistance stays unchanged and consequently, balance of a bridge circuit is destroyed and an electric current corresponding to a concentration of the combustible gas is transmitted to a display for measurement of the concentration of the combustible gas. |
