Abstract: An electrical circuit for controlling at least one electrical load and at least one function thereof by providing, in the active line of an AC circuit, a modulation switching circuit and a plurality of function keys series-connected with at least with the at least one electrical load and a demodulation unit upstream thereof.

Abstract: In high-temperature fuel cells based on an ion-conducting electrolyte, wherein hydrogen and oxygen are converted into water, the cathode of the fuel cell is supplied with oxygen-enriched gas from an air separator, preferably a cryogenic air separator. This oxygen-enriched gas is supplied together with a CO.sub.2 -containing gas in a stoichiometric O.sub.2 /CO.sub.2 ratio.For the recovery of the O.sub.2 and CO.sub.2 components, a partial stream of the cathode outlet gas is recycled; for this purpose, the cathode outlet gas, used for regulating the fuel cell temperature, is cooled with production and/or superheating of steam and recompressed by means of a hot gas blower or a hot gas compressor.

Abstract: Heat transfer equipment is provided having a chamber adapted to contain a bed of free-flowing granular material and a plurality of spirally wound cylindrical tube coils nested together which extend concentrically around a centrally positioned tube collector. Each tube coil is wound on a cylindrical surface having an axis coinciding with the longitudinal axis of the chamber. The tubes at least at the top end of the chamber emerge from the coil and remain on the cylindrical surface as they extend in a direction substantially parallel to the longitudinal axis. The tubes then bend about 90.degree. and extend radially toward the longitudinal axis and connect to the centrally positioned tube collector. In the radial run, the tubes from different tube coils overlap one another on the top of the coils and extend radially over substantially the same outer surface of the tube coils. A retaining device adapted to be removed in sections is positioned below the tubes in the chamber.