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Controlling Pressure Changes in a Liquid Encapsulated Module

IP.com Disclosure Number: IPCOM000076222D
Original Publication Date: 1972-Jan-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Aakalu, NG: AUTHOR [+3]

Abstract

In liquid encapsulated modules, pressure and junction temperature fluctuations due to ambient temperature and air flow changes (storage to operation) has become a problem. This problem has been overcome by introducing a metallic bellows 11 immersed below the surface of the liquid within the encapsulated module. The encapsulated module consists of an enclosed container, having one wall thereof formed by a substrate 4 carrying chips 3. The container is filled with a coolant liquid 5, which comes in contact with the chips 3 to remove the heat therefrom by nucleate boiling. The interior space of the module is filled with fins 7 to enhance the heat removal to the outer fins 8 where the heat can be removed. The cooling liquid 5 is shown as reaching a certain level within the module.

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Controlling Pressure Changes in a Liquid Encapsulated Module

In liquid encapsulated modules, pressure and junction temperature fluctuations due to ambient temperature and air flow changes (storage to operation) has become a problem. This problem has been overcome by introducing a metallic bellows 11 immersed below the surface of the liquid within the encapsulated module. The encapsulated module consists of an enclosed container, having one wall thereof formed by a substrate 4 carrying chips 3. The container is filled with a coolant liquid 5, which comes in contact with the chips 3 to remove the heat therefrom by nucleate boiling. The interior space of the module is filled with fins 7 to enhance the heat removal to the outer fins 8 where the heat can be removed. The cooling liquid 5 is shown as reaching a certain level within the module. The area above the liquid level is used for condensation. This area changes in vapor space with a change in pressure within the module. This pressure change is compensated for by the bellows 11, which is introduced completely immersed within the liquid. The bellows has an opening 12 to the ambient air for operation. Thus, as the heat generated by the chips or the ambient air temperature increases, or air flow outside the module decreases, the pressure within the module increases thus causing the bellows to contract, thereby providing a greater space above the liquid for greater condensation surface. This is essentially an automati...