Abstract: A two or three piece seal apparatus and method is described for providing a positive seal of threads in extreme temperature ranges up to 2000.degree. F. for at least 20 minutes. A stainless steel compression/retaining nut is utilized in combination with a high temperature alloy ring or diamond-shaped seal to effect sealing of the threads.

Abstract: A flow switch with a pressure sensing negative rate membrane. The membrane is designed for integral operation with a venturi element and an actuator. The membrane is a snap action device which, when a differential pressure is sensed, deflects from one position to another to operate the actuator.

Abstract: A fire isolation device having a valve designed to close after a given temperature has been reached by a fusible nose member in the form of a sleeve of fusible material. The device has a passageway therethrough and a self-closing valve member having a poppet and a seat disposed in the passageway with the poppet being biased toward the seat to a valve closed position. At least one aperture through the nose member provides for continuous fluid flow through the device around the poppet and the seat. The nose member is positioned to hold the valve in an open position against the bias on the poppet. The seat has a flow path on its outer end dimensioned to fit the nose member and a flow path towards its inner end larger in diameter than the nose member in an area occupied by the aperture to permit flow therethrough when the nose member holds the valve in an open position. The nose member is made of a material designed to melt in the neighborhood of 700.degree. F. when the fire isolation device is exposed to 2000.