Pressure relief valve
Patent 4930553 Issued on June 5, 1990. Estimated Expiration Date: 
January 23, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
January 23, 2009. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2481713 2731981 2889134 2931673 2987071 3007481 3036593 Pressure-relief valve devices Excess pressure valve particularly for a fluid pressure operated telescopic supporting element employed in underground mining Pressure-relief valve device InventorAssigneeApplicationNo. 299305 filed on 01/23/1989US Classes:137/508, Valve seat or external sleeve moves to open valve137/539.5With followerExaminersPrimary: Hepperle, Stephen M.Attorney, Agent or FirmInternational ClassF16K 015/04AbstractA pressure relief valve comprises a poppet member that is biased toward and sealingly engages a slidable tubular valve seat having unrestrained axial rotation and a central relief flow passage. When the system pressure reaches a threshold pressure the valve seat and poppet are both axially displaced such that at the moment that the poppet is unseated from the valve seat, the valve seat is in motion. The motion of the valve seat when the poppet is unseating or reseating allows the valve seat to comply with any eccentricities of the poppet to achieve uniform seat stresses and low leakage rates as well as acceptable flow rates and low hysteresis. | |
