Pressure relief system for filtration testing apparatus

Abstract

A replaceable primary rupture disk placed in the main body of a cylindrical test chamber functions as a safety device and ruptures to relieve pressure from the chamber when the pressure exceeds a selected maximum value. A free piston that is moveable within the cylindrical to separate the chamber into two variable volume compartments is equipped with a replaceable secondary rupture disk that limits the pressure differential across the piston. The secondary disk ruptures at a pressure differential lower than that required to rupture the primary disk. The maximum pressure that can be contained in any chamber is a pressure equal to the sum of the secondary and primary rupture pressures. The maximum pressure that can be contained in one compartment, if the other is at atmospheric pressure, is the burst pressure of the secondary disk. Threaded end caps are provided with seals that disengage before the threads disengage to bleed down any trapped pressure in the chamber while simultaneously holding the caps to the chamber. Radial spanner wrench openings extending through the cap end are used for tightening and removing the cap and as handling attachment points when the chamber is hot.