Deutsche Forschungs- Und Versuchsanstalt Fur Luft- Und Raumfahrt E.v.

Willi Nieratschker

Gottfried Schneider

Walter Peschka

In a reciprocating pump for cryogenic fluids comprising a pump cylinder in which a piston is oscillatingly displaceable in a sealed state, an inlet valve and an outlet valve, and an annular channel surrounding the pump cylinder on the outer side and forming an outlet for the cryogenic fluid delivered by the pump, in order to attain optimum sealing at the operating temperatures, without the piston motion being impeded at higher temperatures, it is proposed that the cylinder be made of a material with good sliding and self-lubricating properties and a thermal expansion coefficient which is larger than that of the piston, that the dimensions of the cylinder and the piston be so selected that the piston sealingly contacts the inside wall of the cylinder at operating temperature, and that the outlet valve be arranged at the downstream end of the annular channel.

Reciprocating pump for cryogenic fluids

In order to achieve efficient refueling with a method and an apparatus for the automatic refilling of a liquid hydrogen tank in a motor vehicle in which the tank is connected to a liquid hydrogen supply line as well as a hydrogen gas return line, it is proposed that prior to commencement of refilling the liquid hydrogen tank the liquid hydrogen supply line in the vehicle be connected to the hydrogen gas return line and that liquid hydrogen be passed through said lines in order to cool them whereby only after they have been cooled is the liquid hydrogen supply line connected to the liquid hydrogen tank. For this purpose, a bypass line connecting the liquid hydrogen supply line to the hydrogen gas return line is provided in the motor vehicle, and electrically operable closing valves are provided in the liquid hydrogen supply line downstream of where the bypass line branches as well as in the bypass line.

Method and apparatus for the automatic refilling of a liquid hydrogen

A method and apparatus is provided for propelling a hydrogen engine with ogenically stored hydrogen, wherein a pump, cooled down to an operating temperature close to the hydrogen boiling point, feeds hydrogen to the fuel-injection hydrogen engine. In order to improve the method and the apparatus so that the pump need not be maintained constantly at the operating temperature, it is proposed that the pump, when its temperature exceeds its operating temperature level, be purged with cold hydrogen gas and thus cooled down until its temperature drops to the operating level, and that the hydrogen gas that has been passed through the pump be utilized to propel the hydrogen engine in a partial-load range.

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Stuttgart, Germany

Willi Nieratschker