Patent GB-1031721-A (GB)
Title: Improvements in ramjet power plants
Inventor: AUCKLAND DOUGLAS EDWARD
IPC: F02K7/10
Filed: 1962-02-16
Abstract: 1,031,721. Ram jet propulsion units; turbines. BRISTOL SIDDELEY ENGINES Ltd. Feb. 7, 1963 [Feb. 16, 1962], No. 6101/62. Headings F1J and F1T. [Also in Division G3] A ram jet power plant comprises a ram air turbine which is arranged to drive a fuel pump having a discharge pipe connected to a fuel injector system in the ram jet combustion chamber. The fuel system includes a spring- loaded check valve arranged so that the fuel pressure between the pump and the check valve will be higher than the pressure of fuel delivered to the injection system, the check valve comprising a valve body fixed in relation to the engine, a spring-loaded closure member which is operable by fuel pump discharge pressure, and a mass which is mounted for movement in a fore and aft direction relative to the engine, the mass being coupled to the closure member or being part of the closure member and so arranged that the force of the mass on the closure member during forward launching acceleration will substantially reduce the opening pressure differential, across the check valve as compared with the opening pressure differential during zero forward acceleration. The ram jet combustion chamber is indicated at 1 and fuel is supplied thereto through a line 24 and manifold 8, a combustion stabilising device 9, 10 being provided. A pilot combustion chamber 2 is mounted within the combustion chamber 1 and fuel is supplied thereto through a line 22 and pilot fuel injector 3. The fuel pump 16 is driven by a turbine 12 to which ram air is supplied through duct 13, a spill passage 14 controlled by a valve 15 leading from the duct 13 whereby the speed of the turbine may be controlled. Fuel is supplied from the pump to the check valve 18 at pressure P 1  and fuel at pressure P 2  passes through line 22 to the pilot injector 3 and through line 24 by way of a linearising valve 23 to the main fuel injection manifold 8. The linearising valve 23 comprises a piston 25 which is loaded by a spring 26, the piston controlling the open area of a port 27 through which fuel passes to line 24. Combustion chamber pressure P 3  is communicated to the right hand side of the piston 25 by way of a line 32 and orifice 31. The piston 25 is provided with a small orifice 29 through which fuel may pass, the fuel passing through the orifice 31 and line 32 into the combustion chamber. The orifice 31 is controlled by a needle valve 33 whose position is varied by means of a cam 34 which is rotated by a Mach meter so that as the maximum flight Mach number is reached, the needle 33 is moved to restrict the orifice 31 so that pressure in the chamber 30 increases and the piston 25 moves to reduce the open area of the port 27 and so also the flow of fuel to the manifold 8. The check valve 20 is formed with a head 60 of large mass so that upon rapid acceleration of the vehicle at launching, the check valve is opened so enabling fuel to be supplied to the combustion chamber earlier than would otherwise be. The spill air valve 15 is controlled by a servo-device 28, the position of the valve being controlled by a rod 37 which is connected to a flexible diaphragm 36. Fuel from the line 17 passes into the space 35 to the right of the diaphragm, the fuel leaking off through an orifice 39 controlled by a half-ball valve 40 mounted on a lever 41 pivotally mounted at 42 and connected to a rod 43. The rod 43 is connected at one end to an evacuated capsule 45 and at the other end to a diaphragm 48, the rod being connected also to diaphragms 46, 47. The chambers 49, 50, 51, 52 so formed are subjected to pressures P 4,  P 2,  P 3,  P R  respectively, P 4  being a pressure slightly greater than atmospheric since the chamber 49 is provided with a leak-off to atmosphere through a lightly loaded non-return valve 55, P 2  being the pressure of fuel downstream of the check valve 20, P 3  being the combustion chamber pressure and P R  being Rayleigh pressure sensed by a forward facing probe. The unit 28 ensures that the pressure P 2 -P 3  acting on the linearising valve and on the diaphragm 5 of the pilot fuel injector is directly proportional to Rayleigh pressure P R  which is the condition required to maintain fuel/air ratio constant. Should the Rayleigh pressure P R  increase, the device 28 will act to close the spill valve 15, whereupon the turbine speeds up and fuel pump pressure increases. The engine is intended for use on vehicles which are launched by boost rocket.