| 摘要 |
1,023,561. Measuring gas concentration electrically. ENGLISH ELECTRIC CO. Ltd. March 22, 1962 [March 29, 1961], No. 11485/61. Heading G1N. A transducer for measuring the concentration of methane in a gas mixture comprises a thermocouple 14 (Fig. 1) enclosed in a glass tube 15 covered with a platinum wire heater 16, held in position by an impervious layer of refractory material 17. A catalytic coating 18 to promote combustion of the methane is formed on layer 17 by repeated application of a solution of platinum, palladium and aluminium. The transducer element is mounted in a porous housing 25 (Fig. 2) with an impervious base 21. The methane diffuses into the housing and burns at a rate dependent on its concentration. The housing may alternatively comprise an impervious tube with porous end closures ground to a thickness producing the required rate of diffusion. The catalyst 18 may be applied directly to the heater 16. In another embodiment (Fig. 3), a thermocouple junction 104 is enclosed in an alumina tube 105 filled with alumina cement 108 and surrounded by a platinum wire heater 109, secured by impervious layer 110 coated with the catalyst. The transducer may be used in the circuit of Specification 1, 023, 231. |
