| 摘要 |
PURPOSE:To avert the effect of a carbon attack by a gas to be measured by providing a gas shielding layer on the surface of a metallic pipe to be exposed to the gas to be measured. CONSTITUTION:An outside electrode 4 is provided on the outside surface at the closing end of a solid electrolyte body 2 having a blind cylindrical shape and an inside electrode 6 is provided on the inside surface. The electrolyte body 2 is housed into the metallic pipe 12 and a gas passage space 14 is formed between the metallic pipe 12 and the electrolyte body 2. An in-furnace gas is introduced from a gas introducing port 16 for the gas to be measured when the metallic pipe 12 is fitted to a furnace wall 20 by a flange part 18. This gas comes into contact with the electrode 4 and the electromotive force by a difference in oxygen partial pressure is generated between this electrode and an electrode 6 in contact with the air. If an aluminum diffused layer or heat resistant ceramics coating layer is previously formed as the gas shielding layer 38 on the inside and outside surfaces of the metallic pipe 12, the metallic pipe 12 is substantially prevented from coming into contact with the in-furnace gas and, therefore, the sooting by the catalytic power of the metallic pipe material itself is suppressed and the resistance effective to the carbon attack and nitridation attack is obtd. |
