Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
1998-01-13
2001-04-24
Cuchlinski, Jr., William A. (Department: 3661)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C174S050510, C174S034000, C174S034000, C257S704000, C361S818000
Reexamination Certificate
active
06222122
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a new and improved sealed liquid-filled module and to a method of forming the same. More particularly, the invention relates to a module which is sealed to the top and bottom surfaces of a printed wiring board containing heat emitting components. The module is cooled by liquid such as fluorocarbons within the module.
2. Description of Related Art
The use of fluorocarbons to cool printed wiring board components and enclosures for the fluorocarbons to be sealed thereto is known in the art. The present invention, however, provides an improved seal which also can be opened for replacement or repair of components.
SUMMARY OF THE INVENTION
High performance cooling technologies for electronic modules often require the use of a liquid. Fluorocarbon liquids, such as FC-72 and HFE-7100 (sold by Minnesota Mining and Manufacturing Company) are typical examples of liquids which may be used in direct contact with the electronic components and the wiring boards. Such liquids have notably low surface tension and hence must be retained with high integrity seals.
It is also desirable that the sealing method be low cost, suited to rapid automated assembly, and be reversible so that it is possible to reenter a module to make repairs or replacements.
A hot-melt adhesive in conjunction with specially shaped flanges on the edge of the module covers are characteristics of the present invention. The seal is made between the board and the cover using a hot-melt adhesive bead captured in the flange of the cover. The flange is formed with a lip at its perimeter which provides positive location or spacing of the cover relative to the board in a perpendicular direction. The lip may be high enough to accommodate a sufficient thickness of adhesive to provide the required joint flexibility, and wide enough to provide adequate strength in the joint against internal pressure in the enclosure at maximum operating temperatures.
The adhesive may be applied to the cover either as a pre-form or may be dispensed manually or robotically onto the flange. Preferably the pre-form is a bead thicker than the height of the lip of the cover. Such construction guarantees that the adhesive contacts the board. Assembly is accomplished by heating the flange and pressing the cover onto the board. A top and a bottom cover may be applied simultaneously.
When required, removal is accomplished by reheating the flange until the adhesive remelts, and then pulling the cover off the board.
Using an adhesive which is liquid during application makes the joint robust against small surface defects such as scratches or trapped fibers on the board which otherwise might cause a compression loaded gasket to leak.
Clips or clamps may be provided which load the joint against the board or opposing cover if it is desired to keep the board in compression under all operating conditions.
REFERENCES:
patent: 5468910 (1995-11-01), Knapp et al.
patent: 5508888 (1996-04-01), Craps
patent: 5532431 (1996-07-01), Saka et al.
patent: 5703761 (1997-12-01), Heiss
patent: 5731541 (1998-03-01), Bernd et al.
patent: 5847317 (1998-12-01), Phelps
patent: 19600619 (1997-07-01), None
patent: 19706790 (1998-08-01), None
patent: 0 798 808 (1997-10-01), None
patent: WO91 06958 (1991-05-01), None
Conley Rose & Tayon PC
Cuchlinski Jr. William A.
Kivlin B. Noäl
Mancho Ronnie
Sun Microsystems Inc.
LandOfFree
Sealed liquid-filled module and method of forming same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sealed liquid-filled module and method of forming same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sealed liquid-filled module and method of forming same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2544000