Level gauge for liquid helium
US4745806A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 1986 |
| Grant date | May 24, 1988 |
| Priority date | — |
| Expiry date | Jan 24, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S420/901
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A level gauge for liquid helium suitable for use under a higher vapor pressure comprising a sensing element in the form of a ribbon wire made of superconductive alloys and a tube supporting the sensing element which tube is inserted into liquid helium upon measurement. Chemical composition of the superconductive alloys are represented by a formula, Zr.sub.100-x (Ru.sub.1-y Rh.sub.y).sub.x, in which x represents a content of Ru and/or Rh in atomic % and in a numerical value of 17.0.ltoreq.x.ltoreq.22.5 and y represents a numerical value of .ltoreq.y.ltoreq.1. The alloys are made of an amorphous phase obtained by rapid quenching of a molten alloy material and have a superconducting transition temperature, Tc, of 4.5.degree. to 5.2.degree. K. When the level gauge is immersed in liquid helium, a portion of the sensing element below the level of the liquid helium has a zero electric resistance because of the superconductivity of the alloy, so that the level of the liquid helium can be detected by a variation in resistance of the sensing element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.