Compressed gas system, manual valve assembly, and manual valve piston with isochoric thermal isolation zone

1. 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.

2. The compressed-gas system of claim 1 , wherein:

said conduit wall comprises conduit threads;

said coupling body comprises coupling-body threads; and

said coupling-body threads engage said conduit threads.

3. The compressed-gas system of claim 1 , wherein said at least one sealing ring comprises at least one polyurethane sealing ring.

4. The compressed-gas system of claim 1 , wherein said at least one sealing ring comprises at least two sealing rings, each sealing ring formed of a material independently selected from the group consisting of ethylene propylene diene monomer, fluoroelastomer, nitrile butadiene rubber, and polyurethane.

5. The compressed-gas system of claim 1 , wherein said head portion further comprises a head-portion flare adjacent to said blocking rim, said head-portion flare having a trapezoidal cross section that directs flow of compressed gas toward said rim gap.

6. The compressed-gas system of claim 1 , wherein said coupling body further comprises a tool port disposed on a bottom end of said coupling body, said tool port being mechanically coupled to said coupling-body threads.

7. The compressed-gas system of claim 1 , wherein said coupling body comprises:

an insertion portion comprising:

coupling-body threads on an outer surface of said insertion portion that engage corresponding conduit threads on said conduit wall; and

a grasping member that engages a support groove defined in said outer surface of said sealing portion of said manual-valve piston;

an access portion comprising a tool port disposed on a bottom end of said access portion, said tool port being mechanically coupled to said coupling-body threads; and

a coupling-body seal that seals said insertion portion and said access portion.