ELECTRICAL FEEDTHROUGH ASSEMBLIES FOR CONTAINMENT STRUCTURES HAVING SPECIALLY CONTROLLED ENVIRONMENTS AND METHOD OF MAKING

摘要

A construction and method of making a hermetically sealed electrical feedthrough assembly particularly useful for providing electrical connections to and from a containment structure having a specially controlled environment. The feedthrough assembly construction and method of making provide a resultant assembly which achieves the desired electrical performance, while also being able to maintain the integrity of the controlled environment of the containment structure over long periods of time under widely varying environments and for both normal and emergency conditions. The feedthrough assembly includes a header plate containing feedthrough modules employing a specially chosen and designed cast epoxy sealing system which provides for hermetic sealing of each module to the header plate while also permitting each module to be readily mounted and removed. Continuous and simultaneous pressure testing of the integrity of both the inner and outer sealing of each module is made possible by the provision of internal manifolding ports within the header plate which communicate with each other as well as with a porous reticular dielectric preform provided in each module. The porous reticular dielectric preform serves to support the module feedthrough contacts during casting, and afterwards, because it is porous, permits simultaneous pressure testing of the integrity of the sealing of the feedthrough contacts within the modules along with the testing of the integrity of the sealing of the module mountings to the header plate. Each feedthrough module additionally has a construction which provides substantially rigid electrical and mechanical coupling between input and output conductors so as to eliminate the need for insulated wires within the assembly.