Patent ID: 7387320

Claim:
A pressure relief cap for an outlet of a water supply system, comprising: an outer portion defining a front face for generally covering an outlet of a water supply, the outer portion including a seal for being urged against and sealingly engaging a periphery of the outlet and defining a first stop surface; and an inner portion including a connector for coupling and decoupling to an outlet, the inner portion being rotatably coupled to the outer portion such that upon at least partial rotation of the outer portion in a first direction relative to the inner portion the seal is moved axially inwardly relative to the inner portion from a disengaged position to an engaged position to sealingly engage a periphery of an outlet, and upon at least partial rotation of the outer portion in a second direction opposite to that of the first direction the seal is moved axially outwardly relative to the inner portion from the engaged position to the disengaged position to move the seal away from a periphery of an outlet and thereby permit any back pressure within an outlet to vent past the seal prior to decoupling the inner portion; the inner portion further comprising a second stop surface; wherein the inner portion and the outer portion are configured so that while the outer portion is threaded in the inner portion, the seal moves away from the second stop surface as the first stop surface moves towards engagement with the second stop surface.