Cryogenic expansion joint for large superconducting magnet structures
AssigneeThe United States of America as represented by the United States Energy Research and Development Administration
InventorRobert L. Brown
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Abstract
An expansion joint is provided that accommodates dimensional changes occurring during the cooldown and warm-up of large cryogenic devices such as superconducting magnet coils. Flattened tubes containing a refrigerant such as gaseous nitrogen (N.sub.2) are inserted into expansion spaces in the structure. The gaseous N.sub.2 is circulated under pressure and aids in the cooldown process while providing its primary function of accommodating differential thermal contraction and expansion in the structure. After lower temperatures are reached and the greater part of the contraction has occured, the N.sub.2 liquefies then solidifies to provide a completely rigid structure at the cryogenic operating temperatures of the device.
Claims2
In a device for producing a very hot plasma and consequent production of neutrons and x-rays, including a central magnetic core, a plurality of magnetic return legs for said core, a torus liner encompassing said core, a toroidal shield encompassing said torus liner, a plurality of spaced-apart, toroidal superconducting field coils encompassing said shield, each of said coils being wound on a respective coil bobbin, a respective massive outer ring encompassing each of said coils, and a pair of bucking rings mounted between the upper and lower portions of said coil outer rings and said magnetic core, the improvement comprising a first respective peripheral expansion joint mounted between each of said coils and each of said coils bobbins, and a second respective peripheral expansion joint mounted between each of said coils and each of said outer rings, each of said expansion joints comprising a flattened tube containing a refrigerant adapted to be circulated under high pressure therethrough, and each of said flattened tubes containing a pair of spacers mounted therewithin for preventing irremeable flattening thereof, whereby during cooldown of said coils and subsequent operation of said device to produce said hot plasma within said liner, said expansion joints functioning to accommodate differential thermal contraction and expansion between said coils and outer ring and between said coils and coil bobbins while at the same time aiding in said cooldown.
Dependencies are inferred from the claim text.