| 摘要 |
PURPOSE:To keep the inside free from an abrupt change in pressure even if such change exits in an atmosphere by providing a buffer film along a cover for covering an element. CONSTITUTION:The buffer film 18 having gas permeability is provided to an oxygen concn. sensor 17 along the mesh cover 14 for covering the element. The sensor 17 is so disposed that the side having the cover is exposed to the atmosphere where the oxygen concn. is desired to be measured. A prescribed DC power source 16 is connected to the sensor 17 in such a manner that an electrode plate 3 serves as a cathode and an electrode plate 4 as an anode. The oxygen concn. corresponding to the threshold current flowing between the electrodes is known if the value of this threshold current is detected. The fluctuation in the pressure of the atmosphere is absorbed by the film 18 and hardly affects the inside of the sensor 17. The change in the output is, therefore, decreased even if there is the pressure fluctuation in the atmosphere. |
