Patent ID: 7762132
Filing Date: 2010-07-27
Classification: F17C,G01F

Abstract:
1. A refrigerant liquid level measuring method that uses a refrigerant liquid level measuring device including a series sensor arrangement that includes a plurality of sensor elements electrically connected in series, said sensor elements each having a superconducting wire and a normal conductor heater electrically connected to the wire, said superconducting wire and said normal conductor heater being in thermal contact with each other, said series sensor arrangement being provided to cross the liquid level of refrigerant liquid in a container that stores the refrigerant liquid, one of said sensor elements and the other sensor elements in said series sensor arrangement being positioned on one another in the vertical direction, wherein said series sensor arrangement is supplied with a relatively large first current and then a relatively small second current, so that the liquid level of the refrigerant is measured by measuring the electrical resistance value of the normal conductive part of said superconducting wires, wherein current larger than current passed for measuring a refrigerant liquid level is passed, so that said superconducting wire in said series sensor arrangement not only in a refrigerant gas but also in the refrigerant liquid is brought into a normal conductive state, the current for measuring the refrigerant liquid level is then passed, it is awaited that the boundary between the superconductive part and the normal conductive part of said superconducting wire in said series sensor arrangement reaches the same level as the refrigerant liquid level, and the electrical resistance value of the normal conductive part of said superconducting wires in said series sensor arrangement is measured.