Patent ID: 8557454

Claim:
A fuel cell system comprising a reverse flow relief valve comprising: a first feed port; a second feed port; a non-return valve within a main fluid passage extending between the first and second feed ports, the non-return valve configured to allow fluid to pass from the first to the second feed ports and to block passage of fluid in the reverse direction; a bypass fluid passage in fluid communication with the main fluid passage; and a sealing valve biased against an end of the bypass passage between the bypass passage and a purge port, wherein the sealing valve is configured to maintain a seal against the bypass passage when fluid pressure in the first feed port exceeds fluid pressure at the second feed port to prevent fluid flow from the main fluid passage to the purge port through the bypass fluid passage, and to allow fluid flow from the second feed port to the purge port through the bypass fluid passage when fluid pressure at the second feed port exceeds fluid pressure at the first feed port, wherein the second feed port of the reverse flow relief valve is connected to a cathode water injection line, the first feed port is connected to a pump and the purge port is in fluid communication with an interior volume of a water containment vessel.