| 摘要 |
PROBLEM TO BE SOLVED: To make accurately detectable the concentration of carbon monoxide by bringing only a gas to be inspected through an anti-poisoning gas layer with a plurality of specific anti-poisoning gas material into contact with a solid-electrolyte sensor element. SOLUTION: The anti-poisoning gas layer 13 has at least one type out of granular silica gel, zirconia, ultra-stable zeolite, molecular sieve 5A, and powdered α-alumina. The layer is preferably as thick as 5-20 mm in the granular ultra-stable Y-type zeolite, 10 mm or longer in the granular silica gel, 10 mm or longer in the granular molecular sieve 5A, and 15 mm or longer in the granular zirconia. with a granular diameter of 50 mesh or larger and 2 mesh or less, a sufficient effect can be obtained, and the layer thickness is appropriately adjusted according to the effect and sensitivity. The layer is preferably as thick as 15 mm or longer and 20 mm or less in the case of the powered α-alumina. The anti-poisoning gas layer 13 is provided at the upper portion of a sensor cap 1, the upper and lower portions are covered with a mesh, and an anti- poisoning gas material is filled into the inside. |
