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Title: Void-free epoxy castings for cryogenic insulators and seals

Abstract

The design of the Westinghouse Magnet for the Oak Ridge National Laboratory's Large Coil Program (LCP) incorporates a main lead bushing which transmits heat-leak loads by conduction to the supercritical helium stream. The bushing, which consists of epoxy resin cast about a copper conductor, must be electrically insulated, vacuum tight and be capable of withstanding the stresses encountered in cryognic service. The seal design of the bushing is especially important; leakage from either the helium system or the external environment into the vacuum will cause the magnet to quench. Additionally, the epoxy-resin casting must resist mechanical loads caused by the weight of leads attached to the bushing and thermal stresses transmitted to the epoxy via the conductor. The epoxy resin is cast about the conductor in such a way as to provide the required vacuum tight seal. The technique by which this is accomplished is reviewed. Equally important is the elimination of voids in the epoxy which will act as stress-concentrating discontinuities during cooling to or warming from 4K. The types of voids that could be expected and their causes are described. The paper reviews techniques employed to eliminate voids within the cast-resin portion of the bushing.

Authors:
Publication Date:
Research Org.:
Westinghouse Research and Development Center, Pittsburgh, PA (USA). Insulation Dept.
OSTI Identifier:
5731933
Report Number(s):
CONF-830841-10
ON: DE83017273
DOE Contract Number:  
W-7405-ENG-26
Resource Type:
Conference
Resource Relation:
Conference: Cryogenic engineering conference and international cryogenic materials conference, Colorado Springs, CO, USA, 15 Aug 1983; Other Information: Portions are illegible in microfiche products
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ELECTRICAL INSULATORS; SUPERCONDUCTING MAGNETS; CASTINGS; CRYOGENICS; EPOXIDES; SEALS; STRESSES; ELECTRICAL EQUIPMENT; ELECTROMAGNETS; EQUIPMENT; MAGNETS; ORGANIC COMPOUNDS; ORGANIC OXYGEN COMPOUNDS; SUPERCONDUCTING DEVICES; 700202* - Fusion Power Plant Technology- Magnet Coils & Fields; 420201 - Engineering- Cryogenic Equipment & Devices

Citation Formats

Quirk, J F. Void-free epoxy castings for cryogenic insulators and seals. United States: N. p., 1983. Web.
Quirk, J F. Void-free epoxy castings for cryogenic insulators and seals. United States.
Quirk, J F. Sat . "Void-free epoxy castings for cryogenic insulators and seals". United States. https://www.osti.gov/servlets/purl/5731933.
@article{osti_5731933,
title = {Void-free epoxy castings for cryogenic insulators and seals},
author = {Quirk, J F},
abstractNote = {The design of the Westinghouse Magnet for the Oak Ridge National Laboratory's Large Coil Program (LCP) incorporates a main lead bushing which transmits heat-leak loads by conduction to the supercritical helium stream. The bushing, which consists of epoxy resin cast about a copper conductor, must be electrically insulated, vacuum tight and be capable of withstanding the stresses encountered in cryognic service. The seal design of the bushing is especially important; leakage from either the helium system or the external environment into the vacuum will cause the magnet to quench. Additionally, the epoxy-resin casting must resist mechanical loads caused by the weight of leads attached to the bushing and thermal stresses transmitted to the epoxy via the conductor. The epoxy resin is cast about the conductor in such a way as to provide the required vacuum tight seal. The technique by which this is accomplished is reviewed. Equally important is the elimination of voids in the epoxy which will act as stress-concentrating discontinuities during cooling to or warming from 4K. The types of voids that could be expected and their causes are described. The paper reviews techniques employed to eliminate voids within the cast-resin portion of the bushing.},
doi = {},
url = {https://www.osti.gov/biblio/5731933}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1983},
month = {1}
}

Conference:
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