GB1427395A - Gas measuring probe for industrial applications - Google Patents

Abstract

1427395 Electro-chemical analysis WESTINGHOUSE ELECTRIC CORP 16 April 1973 [25 April 1972] 18232/73 Heading G1N A solid electrolyte gas analyzer is associated with a solid porous filter for isolating the solid electrolyte from direct contact by particulate matter present within the environment in which the analyzer is positioned. In the oxygen sensor 20 shown for insertion through a wall of a flue, stack, boiler, furnace, Figs. 1 and 1A (not shown) the solid electrolyte assembly 30 is secured to a tubular extension member 60, extending to the exterior of the wall when the probe is in operation, which is fixedly secured within a tubular thermal insulating member 40 isolating the assembly 30 from the environment. Member 40 is releasably mounted within tubular member 70 forming the exterior of the probe. Mounted to end-piece 49 of insulating member 40 is a support structure 54 including end-plate 55 and streamlined leg members 56, 57, Fig. 3 (not shown) which support and seal tubular porous member 52 against sealing member 59, the porous member 52 isolating the sensor assembly 30 from dust &c. in the furnace but allowing oxygen to diffuse therethrough and pass through holes 62 in heat conductive cap 64 to contact porous platinum electrode 34 on one face of zirconic disc 31. Electrode 34 is electrically connected via conductive support member 32 sealed by disc 31 and which is connected to the support 60, to the exterior of the furnace. The lead 37 from electrode 33 passes through one passageway in entry tube 36 extending to the exterior of the furnace. Two further passages carry leads to temperature measuring element 38 and a heater assembly 35. A fourth passage carries the reference gas, air. In an alternative embodiment Fig. 4 (not shown) two porous members 52 are provided one on either side of the tubular insulating member.