Cryogenic Skirt Support Post
The cold masses of cryostats having vertical axes, like vertical pressure vessels, can be effectively supported by means of a cylindrical skirt that wraps concentrically around the cold mass. The skirt is a cryogenic support post connected at its upper end to the cold mass and at its lower end to the cryostat vacuum vessel. A heat intercept connection to an intermediate temperature refrigeration source can be employed to control heat leak. The support post consists of a composite; e.g., epoxy fiberglass, cylinder with bolted or thermal interference fit end connections. The support post, being a single element support, simplifies cryostat assembly and alignment. The composite cylinder, with a relatively large diameter, lends itself to structural soundness and stability under both static and dynamic loading conditions. Its relatively long length and intermediate temperature heat intercept allows low heat leak to the cold mass. The details of the design of a cryogenic skirt support post as applied to superconducting magnetic energy storage cryostats are presented. Included are support post fabrication, cryostat assembly, and predicted structural and thermal performance. Fabrication of and operational experiences with a prototype support post assembly are discussed.
The cold masses of cryostats having vertical axes, like vertical pressure vessels,1 can be effectively supported by means of a cylindrical skirt that wraps concentrically around the cold mass.
The skirt is a cryogenic support post2-3 connected at its upper end to the cold mass and its lower end to the cryostat vacuum vessel. The advantages of a cylindrical post type support include 1) load carrying versatility, a cylindrical section results in a support that can carry tension, compression, bending, and torsional loads; 2) low heat leak, the use of composite materials with effective heat intercepts results in predictably low heat leaks; and 3) installation ease, the post, involving only a single support member at a suspension point, simplifies installation and alignment.
The cryogenic support post was the major suspension system element of the Superconducting Super Collider magnet cryostats. Extensive experience exists in the construction and installation4 and performance5 of such support posts.
KeywordsGraphite Shipping Helium Epoxy Refrigeration
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