Patent GB-424971-A (GB)
Title: Combustion-product power plant or generator
IPC: F02B71/06
Filed: 1933-08-30
Abstract: 424,971. Combustionproduct plant. PESCARA, R. P., 115, Rue de la Tour, Paris. Aug. 30, 1933, No. 24051. Convention date, Aug. 31, 1932. [Classes 7 (i) and 7 (ii)] [See also Group XXVIII] In a plant for generating hot combustion products under pressure for expansion in a turbine &c., of the type including an internalcombustion air compressor having a pair of floating pistons movable oppositely in a common cylinder, the compressor part delivering air to the combustion chamber for combustion and scavenging, stable operation of the compressor is ensured by the provision of cushioning means for the compressor pistons comprising a chamber in which the fluid pressure varies according to the pressure of the combustion products. In one form, Fig. 1, opposed stepped pistons 1, 2 and 3, 4 work in a combustion cylinder 15 and compressor cylinders 21, 22 and are also provided with pistons 11 in air cylinders 10 serving as cushioning chambers. From the compressor cylinders 21, 22, air is discharged into balancing reservoirs 7 and is fed to piston-controlled ports 8 in the combustion cylinder, preferably through a cooler 20. The combustion cylinder 15 is provided with piston-controlled outlet ports 9, through which the combustion products and scavenging air are discharged through an outlet pipe 16 to an energy-receiving system. Additional outlet ports 13 lead to a chamber 12 provided with a valve 14 controlling an outlet to the pipe 16. The valve 14 is controlled by a piston 17, the upper face of which is connected to the compressor cylinder 22 through a conduit 23 provided with a check valve 24 and a calibrated orifice 60. The valve 14 is normally closed by a spring 18 and can be hand-controlled through linkage 19. On the instroke of the pistons 1, 3, the valve 14 is held open by the pressure on the piston 17, so that discharge takes place through the ports 13 until these are covered by the piston 1. When the pressure drops in the compressor cylinder 22, the check valve 24 closes and after a time the orifice 60 allows the pressure on the piston 17 to fall and the valve 14 to close. Fuel is injected and ignited at the dead point and expansion takes place until the pistons uncover the outlet ports 9, as the valve 14 is kept closed by the spring 18 and the cylinder pressure. In modifications, (1) a cushioning chamber such as 10 is in constant communication with the reservoir 7 ; (2) the air is compressed in stages, with inter-cooling, by pistons corresponding to 4, 11, Fig. 1, and a valve corresponding to 14 is controlled from a sliding cam actuated by the compressor piston ; (3) a reservoir corresponding to 7 is in constant communication with the rear faces of the power pistons in order to balance the pressure on the pistons due to feeding the combustion cylinder with compressed fluid; and (4) the cushioning chambers are formed by spaces behind the power pistons, which communicate with the inlet and outlet pipes, through the terminal ports in the combustion cylinder, at the inner end of the stroke of the pistons. Fig. 7 shows means for regulating a pump 88 for the injection of liquid fuel into the combustion cylinder. A piston 80 is subjected on its front face to the pressure of the fluid entering the receiver, and on its rear face to the pressure of a spring 82 and the fluid pressure transmitted through a conduit 89 ; the piston rod 83 is connected by a link 84, lever 85 and link 86 to a rod 87 controlling the rate of feed of the pump 88. The lever 85 is also connected to the rod 96 of a piston 90 subjected to the action of a spring 94 and to the pressure of the fluid entering the receiver, the pressure being conveyed through a pipe 92 and a chamber 93 provided with a valve 97 normally closed by a spring 98. A lever 99 acting on the valve 97 is connected through a spring 102 to a control lever 101 actuated by hand or a governor; the lever 99 is also pivotally connected to a piston 104 sliding in a recess 107 of the cylinder 91, and the piston rod 96 is provided with a fork 105 for displacing a sliding cam 106 controlling the timing of the fuel injection. The valve 97 is open at starting until the pressure in the receiver and the cylinder 91 is sufficient to close the valve 97 by means of the piston 104 and lever 99. Further fluid pressure moves the piston 80 to the left, reducing the amount of fuel injected, until equilibrium is reached at a pressure controllable by the adjustment of the lever 101. The Specification as open to inspection under Sect. 91 includes also a modification in which the pistons of two or more compressors are coupled so that the expansion period in one combustion cylinder corresponds to the compression period in another, a substantially constant pressure being maintained in the main outlet pipe, which is always in communication with one or other of the combustion cylinders. This subject-matter does not appear in the Specification as accepted.