Patent ID: 7493913

Claim:
A vacuum relief safety valve for attachment to a pump for a swimming pool or spa wherein the pump includes: a pot having a hollow interior; an inlet port through which water from the pool or spa enters the pot under vacuum created by pump suction; an outlet port and an internally threaded drain port for receiving a removable matingly threaded drain plug; the vacuum relief safety valve comprising: a valve housing extending in an axial direction defining an enclosed inner chamber; a base plate at one axial end of the valve housing having an externally threaded extension projecting from the base plate for mating engagement with the drain port to attach the housing to the pump upon removal of the drain plug, and a passage in said extension and said base plate placing said pot interior and said valve chamber in fluid communication; an air inlet aperture formed in the housing and open to ambient air; and a sealing element disposed within the housing and biased against the air inlet aperture so as to effectively seal the inner chamber from ambient air, and adapted to move into the inner chamber and open the air inlet aperture if a maximum allowed vacuum level within the pump is exceeded.