447,111. Power-generating systems. DAWBARN, F. H., 10, Farqhuar Road, Edgbaston, Birmingham. Sept. 6, 1934, No. 25644. [Class 122 (iii)] [See also Groups XXVII and XXVIII] A power plant is of the type comprising a fluid-pressure engine and compressing means driven from the engine for supplying fluid under pressure to a combustion chamber separate from the working space of the engine, the products of combustion either being utilized directly as a driving medium for the engine or being used to heat or vaporize a driving medium, e.g. to generate steam for the engine. Power output apparatus for supplying power from the engine to an external load is adapted to impart the drive from the engine to the compressing means and to increase automatically the rate of driving of the compressing means on increased external load being applied. The invention is described as applied to a combustion-product power plant comprising an air compressor A driven from the engine D through a differential apparatus E through which the external load is driven by means of a belt 69. The compressor shown has twin cylinders with piston-controlled inlet ports and non-return ball outlet valves, but a turbo-blower or a reciprocating or rotary stage compressor may be employed. The compressor supplies air through a pipe 23 to an annular chamber 24 around a liquid-fuel nozzle 19 supplied from a tank 17 in which pressure is maintained by a compressed-air pipe 25. Alternatively, the fuel may be supplied to the nozzle by a pump operated from the shaft driving the compressor. The air-fuel ratio may be varied by the adjustment of a valve 27 in a byepass pipe 26 between the compressor and the pipe 21 leading from the chamber 24 to the combustion apparatus C, shown in detail in Fig. 4. The air-fuel mixture is led in through a conduit 39 to a chamber 31 containing refractory material 40 and fitted with an ignition plug 36 in the cover 35, for starting purposes. The gases of combustion pass through the annular space 43 between the chamber 31 and a steel skirt 32, and through vertical passages in the port member 33 to the interior of a water-tube boiler 41 enclosed in an outer casing 29 containing water. Steam from the casing 29 is conveyed by a valved pipe 48 to mix with the gases of combustion in the chamber 31. The gases leaving the interior of the boiler are conveyed by a valved pipe 46 to the engine, which may be a turbine or a two-cylinder reciprocating engine with a slide valve controlling the communication of the cylinders with the branches of the inlet pipe and with a common exhaust port between the cylinders. Instead of liquid fuel, compressed or producer gas may be employed, or the fuel may be in pulverized or cartridge form. Moreover, the compression chamber of the compressor may be employed as the combustion chamber. Fig. 7 shows the differential gear connection between the shaft 58 of the engine and the shaft 16 of the compressor, the end 60 of which is rotatable in a sleeve 59 secured to the end of the engine shaft. A boss 61 on the sleeve 59 is provided with radial spindles 62 carrying idle bevel wheels 63, which engage a bevel wheel 64 on the compressor shaft 16 and a bevel wheel 65 rotatable on the sleeve 59 and secured to a drum 66 by which the belt 69 connected to the external load is driven. The drum 66 may be provided with an oil-tight cover 68. The power output transmitted to the external load is the algebraic sum of the power supplied by the engine and that transmitted to the compressor, so that the plant adjusts itself automatically to variations of load. On a sudden increase of load and decrease of speed of the output wheel 66, the speed of the compressor is increased and consequently the power output of the engine. The power output may also be varied by adjustment of the control valve 47 on the pipe 46 leading from the combustion head to the engine. Instead of using a differential gear of mechanical form, the engine may drive a dynamo supplying current to a pair of electric motors, one driving the compressor and the other supplying power to the external load. In the case of a steam engine, the products of combustion are passed from the combustion chamber through a boiler, and the resulting steam drives an engine which may be of the condensing type, the condenser cooling water being injected into the boiler, water jacket, &c. used for controlling the temperature of the combustion chamber. The engine may be controlled by means of a throttle valve between it and the steam boiler.