Abstract: An improved safety pressure relief valve which is particularly applicable to valves utilizing pressure taps for sensing the pressure within the inlet nozzle, such as pilot operated valves. The valve includes a valve body having an inlet opening into which a full nozzle is inserted. An annular port surrounds the periphery of the nozzle. An opening in the nozzle leading to the annular port provides for the insertion of a pilot or dipper tube therein. The valve body includes a channel leading between the annular port and an external tap for the pressure sensing line connected to the pilot control means. The design permits the nozzle to be rotated to any angular position with respect to the valve body, thus permitting ready assembly and disassembly of the valve. In a second embodiment, an annular port is used to permit direct injection of purging fluid into the nozzle to prevent its clogging.

Abstract: An improved pressure relief valve with an improved device for securing the blowdown ring of the valve without compromising its pressure integrity. These pressure relief valves include a nozzle extending into the interior of the valve and communicating with the pressure vessel and a blowdown ring which is threaded to the nozzle. Atop the nozzle's opening is a disc which is spring biased into engagement with the nozzle to seal same. The device includes an annular collar surrounding at least a portion of the blowdown ring and the nozzle, a first locking member secures the blowdown ring to the collar and a second locking member secures the collar to the nozzle. The device may utilize the wire seal required by many safety codes.