摘要 |
A protective housing designed as a pressure proof capsule has a pressure relief valve which comprises a porous body 23 and a pore closure 31 about its perimeter for preventing the transition of a flame about an edge of the porous body. Alternative embodiments of pore closures 31 are disclosed, including a soft metal ring about an edge of the porous body that is depressed, such as by a pressure ring, into a gapless imbedding relation to the porous body. An edge region of the porous body can be modified by jacketing materials such as synthetic materials, metals and the like for creating a form fitting bond with the body of the protective housing.
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