Oxford Magnet Technology Limited

Siemens Magnet Technology Ltd.

Wolfgang Stautner

Andrew Farquhar Atkins

Graham Gilgrass

Florian Steinmeyer

The present provides a cryogenic thermal battery arrangement for maintaining a superconducting magnet coil or similar apparatus at cryogenic temperature for a required shipping period, such as thirty days, without consuming a significant amount of costly cryogen. According to another aspect, the invention allows extended shipping periods without incurring excessive costs.

Method and apparatus for maintaining apparatus at cryogenic temperatures over an extended period without active refrigeration

The present invention relates to pulse tube refrigerators for recondensing cryogenic liquids. In particular, the present invention relates to the same for magnetic resonance imaging systems. In many cryogenic applications components, e.g. superconducting coils for magnetic resonance imaging (MRI), superconducting transformers, generators, electronics, are cooled by keeping them in contact with a volume of liquified gases (e.g. Helium, Neon, Nitrogen, Argon, Methane . . . ). Any dissipation in the components or heat getting into the system causes the volume to part boil off. To account for the losses, replenishment is required. This service operation is considered to be problematic by many users and great efforts have been made over the years to introduce refrigerators that recondense any lost liquid right back into the bath. The present invention addresses the problems arising from convection which occurs within a pulse tube refrigerator. The invention provides. in a first aspect, a PTR recondenser wherein, the individual tubes of PTR are insulated by a split sleeve around the whole assembly. Preferably, the sleeve is split into two parts. This configuration has been shown to reduce convection and problems associated therewith.

Pulse tube refrigerator sleeve

MRI or NMR systems

Cryostat systems comprise first and second liquid interconnected helium baths, and a magnet structure which is immersed in one of the baths. The liquid helium is cooled by means of a pumped refrigeration means. The pumped refrigeration means is replaced with a pulse tube refrigerator which can be located directly within the two baths. The pulse tube refrigerator has a &ldquo;cold finger&rdquo; having cold and warm ends. The cold end extracts into the bath housing the coil structure and has heat exchange connected thereto. The pulse tube refrigerator can also serve to cool the radiation shields.

Cryostat systems

The present invention relates to a cooling system for cryostats or transport containers for liquids incorporating a PTR cooler. The cryostat usually consists of several interior cylindrical or otherwise shaped vessels for storing liquids. In particular, the cryostat for NMR applications and related fields usually comprises an outer vacuum case, sometimes also a nitrogen can, as well as one or several radiation shields and the helium vessel housing the superconducting magnet whereas the latter usually is made of NbTi, Nb,Sn, and/or some HTC conductor. It is the aim of the present invention to use a pulse tube cooler by incorporation into an NMR cryostat via an opening, an opening refers to the neck tube itself or to any other means for accessing the cryostat for filling or for energising the magnet or acting conjointly as a pressure relief tube or/and as a drainage outlet e.g. for storage tanks and most generally for using the pulse tube as a means for rigidly suspending or supporting various parts in a cryostat.

Growing community of inventors

Oxford, United Kingdom

Wolfgang Stautner