Patent GB-453508-A (GB)
Title: Fuel supply unit for oil burners or the like
IPC: F23K5/14
Filed: 1935-03-12
Abstract: 453,508. Gear pumps ; stuffing-box substitutes. WEBSTER ELECTRIC CO., Racine, Wisconsin, U.S.A. March 12, 1935, No. 7694. Convention date, March 14, 1934. [Classes 110 (ii) and 122 (v)] [See also Groups I and XXIX] A plant for supplying fuel to an oil burner comprises a two-stage gear pump, a strainer chamber 42 provided with a suction pipe 14, and a pressure - regulated outlet valve chamber 40 with a pipe 16 leading to the burners, and a byepass which leads to a reservoir 60 surrounding the L.P. stage of the pump. A stand-pipe 133, Fig. 2, allows surplus oil from the reservoir 60 to flow along pipe 15 to the tank 12. The return pipe may be dispensed with, the surplus oil instead flowing into the strainer chamber. Gears 98, 99 form the L.P. pump stage, and gears 96, 97 the H.P. stage. Gears 97, 99 are pinned to a driving shaft 23, but gears 96, 98 may revolve freely on the stub shaft 91. The inlet and outlet ports to and from the gears are arranged axially, and communicate with cored or bored passages in the pump casting. One method of sealing the driving-shaft 23 is shown in Fig. 8 and comprises a diaphragm 192 secured to a collar 195 the end face 198 of which is in rubbing contact with a sleeve 197 which revolves with the shaft. A spring 183 presses the surfaces together. A soft metal annulus 203 is pressed between surfaces 202, 201 to secure the sleeve to the shaft. A bore 204 leads back to the suction side of the pump or output from the L.P. stage. The shaft may be grooved at 206 to allow oil to flow back to the reservoir and lubricate the shaft. An alternative sealing means, Fig. 3, comprises a spring 35 pressing axially on washers 36, 37, which engage pieces 38, 39 of leather, rubber, or soft metal. The strainer unit, Fig. 2, has an inlet port 44 leading to a chamber 43, and an outlet chamber, above a metal partition 64, which is open to the suction side of the pump through a port 87. Strainers of foraminous sheet metal 75 are supported upon a perforated tube 68 which is secured between end caps 70, 72 to the partition 64. A coil of wire 66 in a groove 65 secures the partition in position. Cleaning or viewing plugs 47, 55 are provided. In an alternative strainer unit a non-return ball valve is placed at the top of the tube 68 to provide a resistance in the suction flow to the pump and also prevent pulsations returning to the main oil tank 12 and thus causing noise. The H.P. stage takes oil from the reservoir 60 surrounding the L.P. stage and delivers through a conduit 127 into the chamber 112 containing the pressure regulator valve. A piston 148 is pressed upon by a bellows 154 which in turn is biassed by an adjustable spring 166<a>. A needle valve 147 closes the outlet 146 to the burner until sufficient oil pressure is exerted to raise the lower end of the bellows and thus release a piston 223, ball 222, and the needle valve. Upon a further increase in pressure within the chamber 112 the bellows allows the piston 148 to rise further and permits communication between chamber 112 and the reservoir 60 by way of ports 118, 119, 150, 151 and the groove 149. The sleeve 166 may be of brass and the piston 148 of steel.