An improved deflator valve is described herein. The deflator valve has a main body with one or more ports, one or more vents, or port or vent slots for introducing air into or relieving pressure from within the main body in a vortex, circular flow. The deflator valve also includes a piston having an O-ring disposed around an outer circumference of the piston. The O-ring of the piston and the ports and vents are effective for reducing noise and deflation time and improving accuracy and ease of adjusting a pressure setting. The deflator valve can further include a dual or variable rate spring that can achieve an extensive destination pressure range. The deflator valve can also include a threadless lead in, fewer valve stem threads, or a lock chuck for enhanced valve stem attachment methods.

One or more techniques and/or systems are disclosed for bypass flow filtering. A bypass valve filter includes at least one wall configured to engage a surface of a bypass valve and a filter surface having a plurality of openings between an inside of the at least one wall and an outside of the at least one wall. One or more openings of the plurality of openings have a first size and one or more other openings of the plurality of openings have a second size, wherein the first size is different than the second size to define different levels of filtering. The bypass valve further includes an open end configured to allow fluid flow therethrough and to the plurality of openings.

A safety valve is configured for use at temperatures at or above 760° C. (1400° F.). The safety valve includes a closure assembly that can create a self-energizing, metal-to-metal seal. In one implementation, this closure assembly includes a disc with an arcuate finger that circumscribes an axis of fluid flow through a seat. The arcuate finger may extend inwardly toward this axis and downwardly toward the seat. This geometry permits the finger to flex in response to pressure of fluid that impinges on the downstream side of the disc, such flexure causing a first sealing surface on the disc to more forcefully contact a second sealing surface on a seat.

A safety valve is configured for use at temperatures at or above 760° C. (1400° F.). The safety valve includes a closure assembly that can create a self-energizing, metal-to-metal seal. In one implementation, this closure assembly includes a disc with an arcuate finger that circumscribes an axis of fluid flow through a seat. The arcuate finger may extend inwardly toward this axis and downwardly toward the seat. This geometry permits the finger to flex in response to pressure of fluid that impinges on the downstream side of the disc, such flexure causing a first sealing surface on the disc to more forcefully contact a second sealing surface on a seat.

An improved deflator valve is described herein. The deflator valve has a main body with one or more ports, one or more vents, or port or vent slots for introducing air into or relieving pressure from within the main body in a vortex, circular flow. The deflator valve also includes a piston having an O-ring disposed around an outer circumference of the piston. The O-ring of the piston and the ports and vents are effective for reducing noise and deflation time and improving accuracy and ease of adjusting a pressure setting. The deflator valve can further include a dual or variable rate spring that can achieve an extensive destination pressure range. The deflator valve can also include a threadless lead in, fewer valve stem threads, or a lock chuck for enhanced valve stem attachment methods.

A main stage in-line pressure control cartridge. The cartridge selectively controls flow in-line in the same direction as opposed to directing flow at a 90 degree angle like other cartridges. A tubular poppet can be mounted into a body and has a sliding control sleeve that can expose radial holes in the poppet to an open position and to seal the radial holes in a closed position. The cartridge can be configured in numerous ways in order to serve many functions, such as a pressure relief valve, a counterbalance valve, and a flow control valve. The cartridge can also be configured to allow or prevent reverse flow.

A method of shutting down operation of a fuel cell system is disclosed, comprising a fuel cell stack, the method comprising the sequential steps of: i) ceasing a supply of fuel to the fuel cell stack; ii) closing a shut-off valve on an exhaust line in fluid communication with a cathode system of the fuel cell system, the cathode system comprising a cathode fluid flow path passing through the fuel cell stack; iii) pressurizing the cathode system with an air compressor in fluid communication with a cathode air inlet port in the fuel cell stack; and iv) ejecting water from the cathode flow path.

A pressure relief valve is disclosed with a first stage valve that is in series with a second stage valve, with an enclosed cavity between the first stage valve and the second stage valve. The first stage valve relieves pressure from an enclosure into the enclosed cavity between the stages, when the pressure is above a cracking pressure of the first stage valve. The second stage relieves pressure from the enclosed cavity when the pressure is above the cracking pressure of the second stage valve.

One or more techniques and/or systems are disclosed for bypass flow filtering. A bypass valve filter includes at least one wall configured to engage a surface of a bypass valve and a filter surface having a plurality of openings between an inside of the at least one wall and an outside of the at least one wall. One or more openings of the plurality of openings have a first size and one or more other openings of the plurality of openings have a second size, wherein the first size is different than the second size to define different levels of filtering. The bypass valve further includes an open end configured to allow fluid flow therethrough and to the plurality of openings.

One or more techniques and/or systems are disclosed for bypass flow filtering. A bypass valve filter includes at least one wall configured to engage a surface of a bypass valve and a filter surface having a plurality of openings between an inside of the at least one wall and an outside of the at least one wall. One or more openings of the plurality of openings have a first size and one or more other openings of the plurality of openings have a second size, wherein the first size is different than the second size to define different levels of filtering. The bypass valve further includes an open end configured to allow fluid flow therethrough and to the plurality of openings.