Patent ID: 8171953

Claim:
A tank pressure and vacuum relief device for relieving excess pressure or vacuum pressure from an interior of a tank, the device comprising: a housing having a first bore in communication with a second bore, the first bore extending from a first end of the housing and the second bore extending from a second end of the housing, the first end being securable to the tank for communication with an aperture in the wall, the second end being adapted for selective communication with the interior of the tank, and the housing also having an over-pressure opening in communication with the second bore opposite the second end; a pressure relief valve for selectively relieving pressure from the tank, the pressure relief valve including a valve sealing member biased by a first pressure bias means against a pressure valve seat associated with the over-pressure opening; a guide block translatable in an axial direction of the second bore and being biased toward the pressure valve seat by a second pressure bias means, the guide block being translatable independent of the valve sealing member; and, a vacuum relief valve for selectively relieving vacuum pressure in the tank, the vacuum relief valve including a vacuum seal biased against a vacuum valve seat associated with the housing second end, the vacuum seal being biased by a third pressure bias means, wherein the second pressure bias means exerts a force upon the guide block that is at least equal to the weight of the guide block.