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Fixture for Helium Leak Test

IP.com Disclosure Number: IPCOM000042551D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Holovka, CS: AUTHOR [+4]

Abstract

A molded rubber gasket engaged by the perimeter of a sealed module is effective to isolate an attached porous heat sink during a helium leak test. Referring to the figure, base 1 has an opening 2 with shoulder 3 on which molded rubber gasket 4 is retained. A circuit module 5 of substrate 6 and soldered cap 7 with attached heat sink 8 rests on gasket 4 at the edges of the cap. A pair of adjustable clamps 9 (one shown) are tightened sufficiently to insure that the cap edges form a seal at the gasket to isolate the heat sink from the substrate and cap. Each clamp includes a threaded member 10 with captive jaw 11 that can move vertically but not rotate. In operation, the substrate with soldered cap and attached heat sink is soaked in pressurized helium, removed, then placed in the fixture, and clamped in position.

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Fixture for Helium Leak Test

A molded rubber gasket engaged by the perimeter of a sealed module is effective to isolate an attached porous heat sink during a helium leak test. Referring to the figure, base 1 has an opening 2 with shoulder 3 on which molded rubber gasket 4 is retained. A circuit module 5 of substrate 6 and soldered cap 7 with attached heat sink 8 rests on gasket 4 at the edges of the cap. A pair of adjustable clamps 9 (one shown) are tightened sufficiently to insure that the cap edges form a seal at the gasket to isolate the heat sink from the substrate and cap. Each clamp includes a threaded member 10 with captive jaw 11 that can move vertically but not rotate. In operation, the substrate with soldered cap and attached heat sink is soaked in pressurized helium, removed, then placed in the fixture, and clamped in position. Test chamber 12, with gasket 13, is connected to a vacuum source, and placed on base 1 over module 5. Exhausted gases from chamber 12 are checked by a spectrometer for the presence of helium. The fixture arrangement prevents helium absorbed by the heat sink during soaking from later contributing to any detected concentration of helium.

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