Electromagnetic interference shielding device for a portable aircraft engine tester

Claim 1

A portable apparatus for shielding from EMI a portable aircraft engine tester having a plurality of aircraft engine measurement signal inputs that input measurement signals obtained from an aircraft engine, an electrical power input for inputting electrical power, and switches for controlling the aircraft engine tester, the portable shielding apparatus comprising: a portable, seamless, conductive, outer casing having a bottom, four sides, and an open top, at least one of said sides including at least one side opening; a conductive filter box disposed within said outer casing so that a back side of said filter box is connected to said outer casing and covers said at least one side opening, said filter box including: a plurality of holes located on said back side of said filter box within an area that corresponds to said at least one side opening, and a plurality of holes located on another side of said filter box; a first EMI gasket disposed between said connected filter box and said outer casing; a connector disposed within each of said plurality of holes on said back side of said filter box, said connectors having input contact points; a plurality of second EMI gaskets disposed between said plurality of connectors and said filter box; a plurality of EMI filters disposed within said filter box, each filter mounted at an end to one of said plurality of holes on said another side of said filter box, and including: at least one thermocouple EMI filter for filtering a thermocouple measurement signal, said thermocouple filter containing an inductor wrapped with constantan wire, at least one DC signal EMI filter for filtering a DC measurement signal, at least one AC signal EMI filter for filtering an AC measurement signal, and at least one power EMI filter for filtering an electrical power input signal; a conductive deck having a plurality of holes and at least one top opening, said conductive deck connected to said sides of said outer casing to enclose said top of said outer casing; a display window covering said at least one top opening, said display window including: a conductive bezel that covers said at least one top opening and is connected to an outside of said deck, a third EMI gasket disposed between said bezel and said deck, a transparent plastic window disposed on an inside of said deck, a conductive woven screen that is larger than and covers said plastic window so that a periphery of said woven screen that touches an inside of said deck, a fourth EMI gasket disposed over said conductive woven screen, and a conductive backup plate disposed over said fourth EMI gasket for causing a compressive fit of said woven screen and fourth EMI gasket on an inside of said instrument; and a plurality of EMI switch coverings, one EMI switch covering for each of said switches.