Patent GB-792907-A (GB)
Title: Improvements in or relating to a fuel injection circuit for combustion apparatus
IPC: F23D11/28
Filed: 1955-07-04
Abstract: 792,907. Liquid fuel injection circuits. CHRYSLER CORPORATION. July 4, 1955. No. 19312/55. Class 75(1) In a liquid fuel injection circuit for combustion apparatus 10 including by-pass or overflow return type injection nozzles 88 connected in parallel and fed under constant pressure from a pump 72 and having a valve 26 controlling the flow of fuel in the common return pipe 20 from the nozzles to the intake side of the pump 72, the by-pass or return conduit 98, Fig. 2, in a nozzle 88 has a permanent restriction 112 ahead of the valve 26, said restriction normally providing a pressure drop thereacross so that when the nozzle inlet conduit 96 is plugged or has an obstruction thereby reducing the inlet flow rate of fuel, the back pressure on the return conduit 98 is reduced causing the fuel ejected through the spray orifice 106 to remain substantially constant. The pressure drop across the restriction 112 is arranged to be one quarter of the pressure drop across the valve 26 or to one seventh of the pressure drop across the spray head of the nozzle. The intake and discharge openings 92, 94 of the nozzle 88, Fig. 2, accommodate suitable plugs to connect the inlet 92 to a pipe 86, Fig. 1, and the outlet 94 to the pipe 12, each such pipe 12 being connected to a manifold 14 feeding into a cooling device 16. The output of the device 16 is coupled to the valve 26. Inlet 92 communicates with the passage 96 through shank 91 and leads to a chamber 100 communicating with tangential swirl passages 102 in the spray head leading to a swirl chamber 104 having the ejection orific 106. Behind the chamber 104 is the return conduit 108 leading to a chamber 110 in communication with the return conduit 98 adjacent the end of which is the restriction element 112 having a precalibrated restriction passage 118, Fig. 3, and a slot 120 for manipulating the element 112 into and out of the passage 98. The control valve 26 comprises a body 28 and a cover 30 therefore and contains a sleeve 34 sealed at 36 and having a part 38 leading at its outer end through a fitting 22 with the pipe 20 from the cooler 16, and at the inner end leading to an annular groove 40 in sleeve 34. The groove 40 co-operates with an external annular groove 42 on a piston 44 workable in the sleeve 34 and having a port 43 to establish communication between the interior of the piston and the groove 42, the interior of the piston also being in communication with the pipe 74 connected to the intake side of the pump 72. The space in the sleeve 34 beyond the piston head is in communication through a pipe 58 to the discharge pipe 60 of a fuel transfer pump 62 connected to a fuel tank 66 and provided with a pressure-responsive by-pass 64 thereby providing a good reference pressure for the valve 26 and which pressure operates against the internal spring 48 of the valve to adjust the position of the piston when the pressure in the pipe 74 decreases to adjust the opening of the port 38 and permit additional fuel to be by-passed and the pressure restored in line 74 to maintain constant pressure drop across the fuel metering device 68.