Apparatus for determining the presence of combustible constituents in a mixture.

摘要

In a zirconia oxygen sensing apparatus, gas flows through inner (14) and outer tubes (12), one electrodes (18) is attached to the inner surface of the inner tube (14) and another electrode (16) is attached to the outer surface of the inner tube (14). The inner tube (14) is catalytic and the outer catalytic surface therefore is made inert so that an oxygen potential difference is produced between the electrodes (16, 18) which results in a voltage output, as read by an oxygen analyzer (42), which is proportional to the initial level of the combustible in the gas. The utilisation of inner (14) and outer (12) tubes wherein the portion of the gas sample contacting the active electrode (18) is maintained separate from the portion of the gas sample contacting the inactive electrode (16) prevents back or edge diffusion between the electrodes.