Abstract
A novel and simple level indicator for cryogenic fluids is described. It consists of a vessel fitted with a pressure gauge and a fine Cu-Ni tube with manganin wire wound on it, one end connected to the vessel and the other end closed. The same gas as the fluid to be measured is confined in this assembly. With a proper volume ratio between the vessel and the tube and also a suitable heater power, the observed pressure has a linear relationship against the partial length of the tube immersed in the liquid in accord with theoretical considerations. The response time is measured as about 2 minutes. The limitation for the present level indicator is that pressure over the fluid should necessarily be constant. However, this device has so many advantages as follows: very simple, robust, and can be used for any kind of cryogenic fluids.
