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COMBINED AIR VENT AND WATER SEAL VALVE FOR AUTOMOTIVE ELECTRONIC MODULES

IP.com Disclosure Number: IPCOM000005933D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2001-Nov-16
Document File: 1 page(s) / 56K

Publishing Venue

Motorola

Related People

Fred E. Ostrem: AUTHOR

Abstract

An electronic module mounted in the engine compartment of an automobile is subjected to a wide range of external temperature and humidity conditions which can cause condensation to form inside the module unless it is properly vented. At the same time, the module must prevent the ingress of water in the event that the module is flooded with or immersed in water. The present disclosure combines the concepts of air venting and water sealing in a single feature.

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M-ROLA Technical Developments Volume 10 March 1990

COMBINED AIR VENT AND WATER SEAL VALVE FOR AUTOMOTIVE ELECTRONIC MODULES

by Fred E. Ostrem

   An electronic module mounted in the engine compartment of an automobile is subjected to a wide range of external temperature and humidity conditions which can cause condensation to form inside the module unless it is properly vented. At the same time, the module must prevent the ingress of water in the event that the module is flooded with or immersed in water. The present disclosure combines the concepts of air venting and water sealing in a single feature.

   As shown in the diagram, an air vent/water seal valve consists of a number of hygroscopic (water absorbing) disks assembled into a cylindrical cavity having peripheral air passages opening into the interior of the module and a vent hole opening onto the exterior of the module. The hygroscopic disks are retained in the cavity by a solid metal disk which is held captive at the interior end of the cavity.

   In the venting mode, the disks are loose and allow air to pass between them. In the sealing mode, the hygroscopic disks absorb any water entering the cavity and expand against both ends of the cavity to seal against any further water ingress. The action is similar to (but much faster than) the swelling of wooden planks in a ship's hull to seal any gaps in the hull when dry, or the swelling of cedar shingles on a roof to prevent water from entering during a rainstorm. The...