Cooling apparatus for MRI magnet system and method of use
US4782671A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1987 |
| Grant date | Nov 8, 1988 |
| Priority date | — |
| Expiry date | Sep 28, 2007 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25J2290/42
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improvement in cooling apparatus in a magnet system for providing a localized, substantially homogeneous magnetic field for use in magnetic resonance imaging. The magnet system includes a vacuum vessel, a cryogenic containment vessel inside the vacuum vessel and having a coil of superconductive wire along with a quantity of liquid helium to maintain the wire below its critical temperature. The system also includes an inner thermal radiation shield between the containment vessel and the vacuum vessel and an outer thermal radiation shield between the inner shield and the vacuum vessel. A cryogenic refrigerator is supported by the vacuum vessel and extends inside. This refrigerator has a first-stage heat station cooling the outer shield and second-stage heat station for cooling the inner shield. The improvement includes the provision of a tank holding a quantity of liquid nitrogen. This tank is supported in good heat transfer relationship with the first-stage heat station between the vacuum vessel and the outer shield and is spaced from the outer shield. Tubing is provided for transferring the liquid nitrogen from the tank so that it boils in good heat transfer relationship with th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.