GB703284A - Improvements in the regulation of power plants including a free-piston auto-generator and receiver machine such as a turbine - Google Patents

Abstract

703,284. Free-piston generators; regulating. SOC. D'ETUDES ET DE PARTICIPATIONS EAU, GAZ, ELECTRICITE ENERGIE SOC. ANON. April 26, 1951 [April 29, 1950], No. 9816/51. Classes 7(1) and 7(6) In a power plant including a free-piston gas generator having a pneumatic accumulator b and a receiver machine, such as a turbine 16, operated by the gases from the generator, the plant further including regulating means, for example a governor 19, fuel pump 11, and stabilizer 13, for varying the amount of fuel injected into the internal-combustion engine portion 1, 2, 3 3 of the generator in accordance with the load on the turbine and both the mass of air in the accumulator b and the generator working pressure, there is provided an auxiliary regulating device, such as a chamber 20, which functions only in response to sudden and large variations, for example 5 per cent or more, in the turbine lead, the device including control means, such as valves 28, 30 and 31, capable of varying the gaseous mass in at least one of the series of spaces, for example, supercharging casing 9, intermediate gas reservoir 18, interposed between the compressor portion of the generator and the turbine and the accumulator b. The exhaust gases from the engine cylinder 1 are supplied to the turbine 16 through pipes 15 and reservoir 18, although the latter may be dispensed with if the volume of pipes 15 is great enough to ensure a continuous supply of gas to the turbine irrespective of the pulsating output from the cylinder 1. In order to adjust the quantity of air in accumulator b to variations in the flow rate and pressure of the exhaust gases the generator is provided with the stabilizer 13 which introduces air from casing 9 into the accumulator or vice versa. The regulation effected by the governor 19 and stabilizer 13 is insufficient to cope with sudden large increases or decreases in load and thereby necessitates the use of the auxiliary device comprising the chamber 20 containing a gas, such as air under pressure supplied from a starting reservoir 24, which chamber 20 may be constituted by the starting space, not shown, of the gas generator and connected to the casing 9, accumulator b and/or intermediate reservoir 18 by pipes 21, 23 and 22, respectively. The chamber 20 communicates with a distribution reservoir 29 when the valve 28 is opened, which reservoir supplies each of the pipes 21, 22 and 23 through one of three valves 20, whilst each pipe may also be vented to atmosphere by one of three further valves 31. The control for the valves 30 and 31 consists of a dual solenoid and a plunger 49 which, when moved to the left upon a sudden overload, opens valve 28 to supply the turbine 16 with an increased quantity of gas and upon a sudden load decrease moves to the right and opens valves 31, so reducing the quantity of gas delivered to the turbine. The solenoid is energized under the control of a moving contact 44 on a bell-crank lever 42 subjected to the differential effect of the pressure in the intermediate reservoir 18, casing 9 or turbine intake through a piston and cylinder 32, 34 and a relay 36 which moves a rod 37 a distance proportional to the output of an electric generator 17 driven by the turbine 16. The solenoid control may be replaced by an hydraulic one, not shown, and the speed of governor 19 or the stroke length of the combined piston 2, 5 may replace the output of the generator 17 as one of the differential controls. The addition of air or removal of gas may take place in only one of the three spaces 9, 18 or b. The cross-section of pipes 21, 22 and 23 are such that the pressures in the spaces 9 and 18 remain substantially equal to each other. Specification 703,238 is referred to.