Abstract: A heat transfer system has a rotary machine 22 with compressor and expander regions and gas is first compressed in machine 22, passes through heat exchanger 23, is heated in combustor 24, then expands in machine 22, then passes through heat exchanger 23 to heat the gas, then passes through heat exchanger 107 to heat fluid in line 108. The machine 22 drives a heat pump 110 to heat fluid in line 111. Arrangements having two rotary machines are also described. A rotary machine has a rotor eccentrically mounted in a casing having axial end parts and a circumferential part and with vanes defining compartments with the casing and providing a compression region and an expansion region, valve means in the circumferential part adjacent the upstream edge of the outlet from one or both of the regions and responsive to pressure in the adjacent compartment to reduce or avoid excess pressure in the compression region or suction in the expansion region.

Abstract: A rotary machine, having a casing and a rotor rotatable eccentrically in the casing to define an eccentric annulus divided into compartments by vanes, to function either as a compressor or an expansion engine has the vanes pivoted at the rim of the rotor and driven by a mechanical coupling to their operative positions. The vanes are driven by cranks lying in planes outside but parallel to the planes in which the vanes operate. The vanes operate with a minimal clearance between vane tip and casing in order, ideally, to provide zero friction at the vane tip.A power system is disclosed in which air is compressed, heated in a flame tube, expanded under volume confined conditions in a rotary machine as described to an intermediate pressure, and expanded to ambient under volume confined conditions in another rotary machine as described. The machine may drive auxiliaries in a vehicle.

Abstract: A method of applying a ceramic coating to a metallic workpiece is proposed in which the workpiece is heated in a range of 500.degree. C. to 950.degree. C. and the coating directly plasma sprayed thereon in an atmosphere of air before the workpiece has formed any considerable oxide skin thereon. In this way the use of the conventional bond coat is avoided, while the amount of tensile stress on the ceramic at working temperature is reduced by the pre-stressing effect thus induced.