Abstract: A fuel cell power plant (100) includes a stack of fuel cells (102), each having an electrolyte (101) between an anode (104), and a cathode (106), coolant channels (103), an air blower (144), air inlet and outlet valves (139a, 141a), a cathode recycle loop an (135) using the air blower, and a cathode exhaust mix box (173). Shutdown includes recycling cathode air while applying fresh fuel and recycled fuel through the anodes until oxygen is about is about 0.2 or less, or expiration of time. On startup, the air blower is started with the cathode recycle valve (135) open, and the air inlet valve is opened to allow about one-half of the flow of air used during normal operation, to cause hydrogen in the cathode to be gradually consumed, thereby avoiding H2 levels above lower flammability levels in the air outlet manifold. H2 is monitored at exhaust; full air flow is provided after H2 peaks.

Abstract: An aspirator assembly having an air-gas mixing tube mated with an aspirator housing cap with a tapered socket interface and wherein an inlet check valve closure mechanism provides for manually selectable permission or prevention of the opening of ambient air inlet check valves by employing twin lock bars mounted in central swiveling relation about a check valve hinge support member which spans the inlet end of the aspirator housing cap.