Abstract: A relief system for process fluids under pressure. The system includes a normally open isolation valve in fluid communication with a process system under pressure through an upstream conduit. A buckling pin actuator is in fluid communication with the upstream conduit through a sensing line. A spring activated actuator is engaged with the isolation relief valve in order to retain the isolation valve in a closed position. A buckling actuator bypass valve is supplied with non process fluid pressure to an input port and the buckling actuator bypass valve also includes a first output port to the spring activated actuator and a second output port to a vent whereby pressure in the process system above a predetermined level will actuate the buckling pin actuator, moving said buckling actuator bypass valve to said second outlet port to vent and thereby moving the spring activated actuator in order to open the isolation valve.

Abstract: The disclosure is directed to a thermal protection systems for protecting instrumentation transducers having a low maximum operating temperature in the range of 200 degree F. to 900 degrees F. when exposed to operating environment greater than 2000 degrees F. The embodiments of the protection system include the use of zinc solid-to-liquid phase change as a heat sink, water-to-steam phase change as a heat sink and thermal electric cooling combined with a multi-foil insulation material.