Pressure driven hermetically sealed pump for fuel cell system

A hydrogen feed system for a fuel cell arrangement, said feed system being adapted to receive hydrogen at a delivery pressure from a supply, to relax said hydrogen from said delivery pressure to a feed pressure and to feed said hydrogen to a fuel cell arrangement, said fuel cell arrangement having an anode side with an inlet for hydrogen, an outlet for hydrogen containing exhaust gases and a hydrogen recirculation circuit extending between said outlet and said inlet for receiving hydrogen containing exhaust gases at a return pressure from said outlet and feeding them together with hydrogen from said supply to said fuel cell arrangement, said hydrogen feed system comprising a pump provided in said hydrogen recirculation circuit and adapted to receive said hydrogen containing exhaust gases at said return pressure and increase their pressure for feeding them with hydrogen received directly by said pump from said supply to said fuel cell arrangement, said pump being driveable by pressure energy derived from said hydrogen at said delivery pressure.

A hydrogen feed system in accordance with claim8, said double-acting piston pump having a cylinder, first and second piston heads and a connecting member for coupling said piston heads together in spaced apart relationship, said piston heads being movable to and fro in said cylinder, said cylinder having first and second ends, there being a first cylinder space formed between said first piston head and said first end and a second cylinder space formed between the second piston head and said second end, each said cylinder space having an inlet in said hydrogen recirculation circuit for receiving hydrogen containing exhaust gases coming from said fuel cell arrangement and an outlet in said hydrogen recirculation circuit leading to said fuel cell arrangement, with respective non-return valves being associated with each inlet and outlet of said cylinder spaces.

A hydrogen feed system in accordance with claim 22, said first and second membrane chambers having respective first and second gas impermeable membranes, said first membrane dividing said first membrane chamber into first outer and inner chamber spaces and said second membrane dividing said second membrane chamber into second outer and inner chamber spaces.

22 A hydrogen feed system in accordance with claim 24, said first and second membranes having respective centers and said pump further comprising a coupling element, said first and second membranes being mechanically coupled together by said coupling element which is attached to said membranes at said centers, so that they are synchronously deflectable in a direction substantially perpendicular to the gas passage.

A hydrogen feed system in accordance with claim 23, said outer chamber spaces each having an inlet in said hydrogen recirculation circuit for receiving hydrogen containing exhaust gases from said fuel cell arrangement and an outlet leading to said fuel cell arrangement, there being a respective non-return valve associated with each inlet and outlet of said outer chamber spaces and said inner chamber spaces being connected via corresponding first and second passages to said gas passage.

A hydrogen feed system in accordance with claim 25, and further comprising a rocker valve having first and second positions and arranged in said gas passage, whereby when said rocker valve is in its first position, said first inner chamber space is closed off relative to said first section of said gas passage and said second inner chamber space is closed off relative to said second section of said gas passage but is connected to said first section and, when said rocker valve is in said second position, said second inner chamber space is closed off relative to said first section of said gas passage and said first inner chamber space is closed off relative to said second section of said gas passage but is connected to said first section.

A hydrogen feed system in accordance with claim 26, said rocker valve having first and second sealing limbs and a tilting limb which are arranged in the manner of a Y-shape, said limbs being fixedly connected together at a connection point and being pivotally mounted in the region of said connection point, and said first and second sealing limbs each being associated with a respective one of said first and second passages.

A hydrogen feed system in accordance with claim 28, said drive element having a rod section with first and second ends and being substantially rigidly connected to said coupling element at its first end and having a V-shaped fork section formed by two fork limbs at its second free end, in such a way that a force can be exerted by said fork limbs on said tilting limb.

A hydrogen feed system in accordance with claim 24, and further comprising a collecting line leading to said fuel cell arrangement, said outlets of said outer chamber spaces and said second section of said gas passage being connected to said collecting line.

A hydrogen feed system in accordance with claim 33 and further comprising a pressure regulating valve which is provided at said outlet of said hydrogen recirculation circuit.