Patent GB-694371-A (GB)
Title: Control system for a rocket motor
Inventor: ALLEN SIDNEY
IPC: F02K9/56
Filed: 1950-09-08
Abstract: 694,371. Jet propulsion plant ARMSTRONG SIDDELEY MOTORS, Ltd. July 23, 1951 [Sept. 8, 1950], No. 22153/50. Class 110(iii) [Also in Group XI] A rocket in which a liquid fuel e.g. a mixture of methyl alcohol and water,.and a liquid oxidizer e.g. liquid oxygen or nitric acid, are pumped by separate pumps through separate valve means to a combustion chamber fitted with ignition equipment, has control means which, when the motor is to be operated, supplies oxidizer to the oxidizer system to cool it and initiate priming of the oxidizer pump and also prevents operation of the fuel pump until after the oxidizer pump has attained a stable delivery to a by-pass leading back to the oxidizer reservoir. In the rocket shown, Figs. 1 and 2, a fuel tank 31 and a liquid oxygen tank 32 are provided with pressurising valves 33 which, when operated, admit nitrogen from the bottles 34 to the tanks. A further supply of nitrogen is supplied through a reducing valve 40 and a control valve 44 to a pneumatic actuator 45 which operates a valve 46. Operation of the valve 44 causes the valve 46 to open and liquid oxygen then flows by gravity through the oxygen supply pump 47 and pipe 48 to the inlet 11 of a combined stop and throttle valve means 49 shown in Fig 3 which is described in Specification 694,372. The combined stop and throttle valve means comprises an inlet 11 and an outlet 12 between which are arranged a throttle valve 15 and stop valve 17 both of which are biased to the closed position. The valve 15 has a number of openings 14 which allow a predetermined quantity of fluid to pass even when the valve is closed. A normally open by-pass 19, controlled by a fluid operated valve 21, and an opening 23, controlled by a normally closed valve 24 are also provided. The liquid oxygen flows through the by-pass 19 of the valve 49 through the conduit 20 back to the tank 32. For priming purposes, a pipe 52 connects the highest point of the pump 47 with the conduit 20 through a pressure responsive valve 53 which closes the passage through the pipe 52 when the output of the pump reaches a predetermined value as described in Specification 684,230. After a minimum time of about five minutes, the master switch 56 is closed and the electrically operated valve 60 opened. This allows nitrogen under pressure to flow to the valves 33 which are then opened to pressurise the tanks 31, 32 and to pneumatic device 64 which engages a clutch 65 connecting the oxygen pump 47 and fuel pump 66 to appropriate driving means (not shown). The pump 47, being already primed, immediately develops a predetermined pressure which actuates a two-way switch 68 which, in turn, energises the coil 69 of a time delay switch 70. After a predetermined delay of about four seconds the switch 70 closes and energises the coil 78 and opens the valve 79 which allows fuel to flow to the pump 66. The pump 66 discharges fuel to the combined stop and throttle valve means 82 which is similar to that shown in Fig. 3. The valve 82 passes some of the fuel through a normally open, pressure-operated, valve 83 to waste and, in parallel, along a pipe 85 to the igniter equipment 86 which may be described in Specification 694,373, [Group XI]. When the fuel pump develops a predetermined pressure, the switch 87 is closed and a solenoid operated valve 90 opened which allows nitrogen under pressure to flow to the valve 93 and open it so that a small supply of liquid oxygen is delivered to the igniter equipment 86. The switch 87 also energises the booster coil 97 of the igniter equipment. When ignition occurs, the pressure in the igniter equipment rises and operates the switch 99 which de-energises the circuit through the coil 97 and energises the solenoid of the valve 102. The valve 102 opens and allows nitrogen under pressure to close the valve 83 and to open the stop valves 17 in the valve means 49, 82. As a consequence a predetermined quantity of fuel and oxidizer passes through the openings 14 of the throttle valves 15 to the combustion chamber 107. The oxidizer may enter the chamber 107 direct through an injector and the fuel my be used to cool the combustion chamber and then passed into the chamber through an annular space surrounding the oxidizer-injector. When the rocket is operating, the rise in pressure in the chamber 107 actuates a switch 75 which de-energises the solenoid operated valve 90 and causes the valve 93 to cut off the supply of oxidizer to the igniter equipment. At the same time, the time delay switch 70 is de-energised and re-sets itself in readiness for the next start. The operation of the switch 75 also prepares a circuit for the operation of the throttle valves 15 of the valve means 49. 82. Up to the present, the rocket has been working at a predetermined minimum thrust. When full thrust is required, the switch 119 is closed. This causes valve 120 to open and allows pressure to be applied to open the throttle valves 15 of the valve means 49, 82 and to close the by-pass valve 50. To stop the motor, the main switch 56 may be opened or an emergency switch 124 operated to open the switch 57. A dump valve 125, of the type described in Specification 682,732, operated by the fuel pump discharge pressure, may be employed.