| 摘要 |
PURPOSE:To enable measurement of vapor pressure accurately even if alkali metal is condensed in part of the sensor surface or mist thereof is deposited, by combining polarity inversion detection circuit or the like to a ceramic partition wall of beta-Al2O3. CONSTITUTION:Being controlled by a control circuit 32, a power supply unit 31 supplies input to sheathed heater 12, which causes the liquid Na 11 in a partition tube 4 to be heated, so that the Na vapor pressure P1 in chamber 10 becomes higher than the Na vapor pressure P2 in a passage 1. Due to the difference between P1 and P2, a voltage of polarity to produce positive voltage at the side of external terminal 8 of electrode 5 is generated between terminals 8 and 22. Upon lapse of specified period of time, the unit 31 cuts input to the heater 12, and supplies input to a blower 16 of blower duct 15. Then, Na 11 is quickly cooled until P1 becomes lower than P2, then the voltage between the terminals 8 and 22 is inverted in polarity. Due to the output signal from a polarity inversion detection circuit 34 issued at the time of this inversion, the temperature of a temperature detection circuit 33 to which sheathed thermocouple 17 is connected is recorded in a recorder 35, so that P1 and P2 can be judged from the saturated vapor pressure curve. |
