JPS54155864A - Liquid level gauge - Google Patents

Abstract

PURPOSE:To detect the liquid level plsitions on the low temperature side by detecting the change of the number of vibration owing to the thermal oscillation produced when a pipe having been hermetically sealed of the ordinary temperature side into cryogenic fluid by a piezoelectric element by way of a diaphragm. CONSTITUTION:One end of a pipe 11 of both ends being open is inserted into the cryogenic fluid to be measured and a casing 12 is mounted to the other end 11a to hermetically seal the same. A diaphragm 14 having a protrustion 15 on the side opposite from the pipe 11 is disposed in the space 13 is the casing 12. Part of the upper wall 13a near the prtrusion 15 is thinned to plate form and a piezoelectric element 17 is provided in close contact with this plate form portion 16 on the side opposite from the protrustion 15. A high frequency connector is connected to the piezoelectric element 17 and this constitutes the liquid level gauge. Hence, thermal oscillation is caused by the low temperature side and ordinary temperature side of the pipe 11 and the change in this vibration is converted to an electric signal by the piezoelectric element 17. This electric signal is drawn to the outside through the high frequency connector 18. Whereby the level of the liquid is detected.