| 摘要 |
PURPOSE:To easily obtain an industrially usable SO2 gas sensor excellent in heat resistance and durability, by using alpha-alumina as the solid electrolyte of the SO2 gas sensor. CONSTITUTION:alpha-Alumina with an Na2O:Al2O3 ratio of about 1:11-1:5 is used as a solid electrolyte to form a cylindrical pipe 2. For example, a gas inflow pipe 9 made of alpha-alumina is provided in the pipe 2 in such a state that the leading end of the pipe 9 is brought into contact with the closed wall 2a of the pipe 2 and an outflow port 9a is provided to the part thereof. The periphery of the outflow port 9a as a center is filled with Pt wool 7 as a catalyst while a platinum lead wire 5 is inserted into the wool 7 and the leading end of the wire 5 is brought into close contact with the wall 2a in a state bent in parallel to said wall 2a to form an electrode 5a. alpha-Alumina pipe 3 having the same diameter as the pipe 2 is connected to the pipe 2 at the contact surface 4 of the end part 3a thereof and the wall 2a of the pipe 2 by using heat resistant glass. A Pt-Pt.Rh thermocouple 11 is mounted into an alpha-alumina protective pipe to be provided in the pipe 3 and the periphery of the leading end of the pipe 10 is filled with Pt wool 12 to form an SO2 sensor 1. A sample gas is flowed through the pipe 3 of the sensor 1 and a reference gas through the pipe 5 thereof. By this method, the sensor excellent in heat resistance and durability is obtained. |
