PRESSURE AND VACUUM RELIEF VALVE MECHANISM FOR A FLUID STORAGE TANK

摘要

PRESSURE AND VACUUM RELIEF VALVE MECHANISMFOR A FLUID STORAGE TANKABSTRACT OF THE DISCLOSUREA pressure and vacuum relief valve mechanism which canbe installed in a vent opening in the top wall of a fluidstorage tank. The valve mechanism includes a valve housingwith a central bore therethrough. One end of the borecommunicates with the vent opening to ambient atmosphere andthe opposing end communicates with the interior of the tankabove the stored fluid. A single, integral valve member ismovable in the bore of the housing. The valve member hasa plurality of valve seats formed thereon and valve operableclosure means cooperably engaged respectively with the valveseats. There is a valve seat and closure means for relievingexcessive pressure and a valve seat and closure means for relievingexcessive vacuum in said tank interior, these valvingarrangements normally being biased closed. There is a thirdoverturn valve seat and cooperable valve closure means normallyoperable to maintain this valving arrangement open but operableto close the same when the tank is tilted or overturned so asto prevent leakage of stored fluid through the vent opening.-1-