Abstract: A heating system including a heat pipe containing evaporable heat transporting material, a closed reservoir containing heat-accumulating material within said heat pipe, and a quantity of said evaporable material in said reservoir for maintaining the same pressure in said reservoir and in said heat pipe.

Abstract: A heat exchanger (air preheater) comprising two series-connected sections, the section comprising the flue gas outlet having double-walled partitions with intermediate spaces in which a vaporizable medium is present for isothermalizing the said partitions in the flow direction in order to prevent the deposition of corrosive substances such as sulphur compounds.

Abstract: A drive system for a blower, forming part of an external heating circuit of a Stirling engine, is disclosed. A viscous-shear coupling is arranged with the input member thereof concentrically surrounding a one-way clutch which in turn is mounted on an accessory shaft extending through the assembly. The drive system is effective to operate only after the engine has reached predetermined thermal operating conditions; a power transfer is made from an auxiliary blow motor drive to said system upon reaching said conditions.

Abstract: A hot-gas reciprocating engine comprising at least three pistons which each separate a space of lower temperature and a space of higher temperature. Each space of lower temperature is each time connected, via a regenerator and a heat exchanger which is in heat-exchanging contact with a reservoir containing heat-accummulating material, to a space of higher temperature having volume variations which lead in phase as well as to a space of higher temperature having volume variations which lag in phase. The said connections include valves which are operated by means for selectively releasing one of the two connections, each of the pistons co-operating, by way of a drive rod, with a tiltable plate which is mounted on a rotatable shaft.

Abstract: A heater head assembly of the type useful in a hot gas engine is disclosed. The assembly has a plurality of tubes or passages providing a communicating connection for the gas between high temperature working chambers and regenerators. In one embodiment, manifold extensions are provided for each of the working chambers and regenerators and between which banks of heater tubes extend. Each of said manifolds contain at least one blind flow turn-around or reverter structure whereby hot gases traversing between a working chamber and a regenerator must travel the spacing therebetween a minimum of three times. Each of said tube banks are formed by uniting two plys of sheet metal along spaced pairs of parallel lines of brazing, the zone within each pair of brazing lines being expanded to define gas passages for said tube bank and the zone between pairs of brazing lines being perforated to admit cross-flow of a surrounding heating medium.

Abstract: A fuel-air regulating system for hot gas engines in which a correctly selected ratio between fuel and air is maintained in spite of variations in the engine load. The system comprises temperature-controlled means for supplying fuel and air required for the combustion in a constant amount per unit of time which exceeds that which the engine requires for maximum power output when the high temperature level of the working gas had dropped to a predetermined lower temperature limit and for reducing the fuel and air supply to a constant amount per unit of time which is less than the amount required at idling of the engine when the temperature of the working gas has reached its predetermined upper limit.

Abstract: A hot-gas engine including a heater and a source of heat in combination with a switching device for conveying heat from the heat source to heater, the device including a pair of spaced heat pipes with third intermediate heat pipe and means for introducing inert gas into said third heat pipe and removing said gas to vary the vaporization point therein and the rate of heat transfer therethrough.

Abstract: A hot gas engine including an injector for introducing a mixture of air and fuel into the combustion chamber to heat the working medium which is circulated in a system of ducts. Fresh air for the combustion of the fuel is preheated in a heat exchanger by exhaust gases from the combustion chamber and conducted to the fuel injector. A heating system for passing a heat exchange fluid to a space to be heated surrounds the combustion chamber, and the heat exchange fluid is thus heated by heat exchange with the exhaust gases.