Abstract: During the operation of a fuel-cell assembly, the latter is supplied with ambient air with the aid of a liquid ring pump. Any foreign matter that is contained in the air is taken up by the service fluid of the liquid ring pump. The charging of the service fluid with foreign matter is controlled. In particular, the service fluid is continuously conducted in an circuit via a purification device.

Abstract: Mechanical stresses of the membrane of a fuel cell can be reduced by virtue of the fact that the supply of feed gas to a gas chamber of the fuel cell takes places, initially, by means of a first pressure increasing speed and then by means of a second pressure increasing speed. The first pressure increasing speed is slower than the second pressure increasing speed. Pressure surges are prevented in the membrane due to the lower pressure increasing speed in the first phase of the gas supply, and as a result, the life span of the membrane is increased.

Abstract: A fuel cell installation includes a cascaded fuel cell block, for essentially waste gas-free operation. An installation of this type presents the problem that the cascaded fuel cell block is complex to produce and therefore expensive. To solve this problem, the fuel cell installation has several steps which are arranged in a cascade, each of the steps comprising one or more non-cascaded similar fuel cell blocks. A fuel cell installation construction including modular similar fuel cell blocks is economical and simple to produce in series.

Abstract: The invention relates to a fuel cell system comprising a fuel cell stack whereon the reaction gas can be guided to the gas inlet slide and which comprises at least one flush valve, which is arranged on the gas outlet side, on a flush cell. A control device, which controls the actuation of the flush valve according to the voltage of the flush cell, is provided. The voltage tap is carried out in the region of the gas outlet towards the flush valve, in particular on a bipolar plate. Significantly sensitive and precise control is obtained by means of the lower voltage tap compared to a higher voltage tap and voltage dips are actively prevented in the flush cell, which enables the total risk of corrosion the maintained at a minimum for the bipolar metal plate.

Abstract: In fuel cells operated with damp operating gases, water condenses out as the operating gas flows from the damping device to the fuel cell block. Typically, the condensed water runs into the fuel cells and impairs their operation. A fuel cell block according to the invention includes fuel cells, a an operating gas delivery line, and a condensed water separator connected to the operating gas delivery line for preventing the condensed water from flowing into the fuel cells.

Abstract: In fuel cells operated with damp operating gases, water condenses out as the operating gas flows from the damping device to the fuel cell block. Typically, the condensed water runs into the fuel cells and impairs their operation. A fuel cell block according to the invention includes fuel cells, a an operating gas delivery line, and a condensed water separator connected to the operating gas delivery line for preventing the condensed water from flowing into the fuel cells.

Abstract: A fuel cell installation includes a cascaded fuel cell block, for essentially waste gas-free operation. An installation of this type presents the problem that the cascaded fuel cell block is complex to produce and therefore expensive. To solve this problem, the fuel cell installation has several steps which are arranged in a cascade, each of the steps comprising one or more non-cascaded similar fuel cell blocks. A fuel cell installation construction including modular similar fuel cell blocks is economical and simple to produce in series.

Abstract: Method for cleaning vessels and in particular, steam generators, having deposits which are dissolved chemically and removed mechanically. The copper compounds present in the deposits are dissolved chemically and subsequently, loose deposits and liquids are removed mechanically. Encrustations still remaining are softened chemically and finally, the loosened deposits as well as the remaining chemicals are flushed out.