Patent ID: 8511334

Claim:
A compressed-gas system comprising a fuel storage vessel, a refueling port, a joint conduit, a compressed-gas conduit, and a manual-valve assembly, wherein: said joint conduit is in fluid communication with at least one of said refueling port and said fuel storage vessel; said compressed-gas conduit is in fluid communication with said joint conduit; said compressed-gas conduit has a conduit inside diameter and is defined by a conduit wall; said compressed-gas conduit comprises a conduit opening to an ambient-pressure external environment; said manual-valve assembly comprises: a manual-valve piston having a head portion, a stem portion, a sealing portion, and at least one sealing ring, wherein: said head portion comprises a top end, a bottom surface, and a blocking rim, said blocking rim defined on an outer surface of said head portion between said top end and said bottom surface; said blocking rim has a blocking-rim width less than said conduit inside diameter; said stem portion is interposed between said head portion and said sealing portion, such that said stem portion is connected to a top surface of said sealing portion and to said bottom surface of said head portion; said stem portion has a stem-portion width less than said blocking-rim width; and said sealing portion has a sealing ring groove defined in an outer surface thereof; and a coupling body coupled to said manual-valve piston; said at least one sealing ring is seated in said sealing ring groove of said manual-valve piston; and said manual-valve assembly is disposed within said compressed-gas conduit, such that: a rim gap is defined between said blocking rim of said head portion and said conduit wall; an isochoric thermal isolation zone having a constant volume without any pressure drops is defined in said compressed gas conduit between said bottom surface of said head portion and said top surface of said sealing portion radially outwardly from said stem portion to said conduit wall; said at least one sealing ring prevents fluid communication between said isochoric thermal isolation zone and said conduit opening; compressed gas enters said isochoric thermal isolation zone through said rim gap during a refueling operation or a starting operation and stagnates in said isochoric thermal isolation zone; and during said refueling operation or said starting operation, said isochoric thermal isolation zone thermally buffers said at least one sealing ring from cold compressed gas flowing through said joint conduit.