Patent GB-727762-A (GB)
Title: Improvements in or relating to compressor units of the semi-rotary engine type, and power plants
IPC: F04C21/00
Filed: 1953-01-19
Abstract: 727,762. Semi-rotary engines and compressors; gas turbine and jet propulsion plants. ETESSAM, A. H. March 4, 1954 [Jan. 19, 1953], No. 1506/53. Classes 110 (2) and 110 (3). [Also in Group XXIX] Compressor unit.-A unit of the semi-rotary engine type for producing separate streams of compressed air and burnt combustion gases comprises two coaxial cylindrical casings 1, 2 closed by end-plates 4, 5 forming an annulus 3 in which oscillate an even number of doubleacting pistons, there being four, 7, 8, 9, 10, in Fig. 2 forming working spaces 42, 43, 44, 45, the pistons being connected in pairs so that as spaces 42, 44 increase in volume due to the action of expanding gas from injected fuel, the spaces 43, 45 decrease, so compressing the air contained therein. A fixed hollow shaft 21 carries eight pivotable spiders 13-20 each having two arms 27 extending through slots 28 in the casing 2 and secured to a pair of diametrically opposed pistons. Each pair of pistons is connected by four spiders and each piston has four piston-rings 11. A linkage mechanism 29 outside end-plate 5 ensures that the pistons 7-10 move in proper timed relationship with respect to each other. Each working space has at least one inlet port 47, one exhaust port 46, one high-pressure discharge port 48 and one fuel injector 49. The high-pressure port 48 leads to a duct 53 in which is seated a valve 52. The spider 13 has a cylindrical extension 22 carried in a boss 23 on the end-plate 4, the surface 50 of the extension 22 forming a cam profile for followers 51, 54 which operate the valves 52 and the injector 49. In Fig. 2 the working space 44 diminishes as pistons 7, 8 approach each other, so closing the ports 46, 47 and the air in the space is compressed. The valve 52 opens halfway through this stroke when compressed air is discharged through the port 48. The valve 52 closes before the end of the stroke when fuel is injected, the fuel burns and the expanding gas drives the pistons 7, 8 apart, so causing compression of the air in spaces 43, 45. When the ports 46, 47 are again uncovered the exhaust is discharged through port 46 as air from a lowpressure compressor enters through port 47. The burning of fuel in spaces 45, 47 causes pistons 7, 8 to commence another compression stroke in spaces 42, 44. A coolant, preferably water or air, flows through ducts 75 in the walls of the casing 1, 2. The pistons 7-10 are cooled by air or water and/or by oil circulating through passages 76, 77, 78, 79 in the shaft 21, the spiders 13-20 and their arms 27. Gas turbine plant.-The compressor described may be used to replace the reciprocating compressor in the gas turbine plant of Specification 699,854. The compressor described is connected to deliver compressed air through a heater to a high-pressure turbine which drives a rotary compressor to deliver low pressure air to the compressor unit. The exhaust from the high-pressure turbine and the'burnt gases from the compressor unit drive a low-pressure power turbine. The two turbine rotors may be coupled together by a drive-shaft 80 passing through the hollow shaft 21 of the compressor unit. Jet propulsion plant.-This gas turbine plant may form a jet propulsion unit by the lowpressure power turbine driving a blower which drives air through the passages 75 in the compressor unit to heat the air which is further heated in a combustion chamber. This heated air is mixed with the exhaust from the lowpressure turbine (both gases being adjusted to the same pressure) and expanded through a nozzle to form a propulsion jet.