GB1426060A - Fluid injectorp - Google Patents

Abstract

1426060 Valves TECTRON ENG Ltd 26 Nov 1973 [20 Nov 1972] 55345/72 Heading F2V [Also in Division F4] A fluid injector, e.g. for injecting liquid fuel into a furnace, comprises a tip sealing valve 6, 7, 8, 9 for controlling fluid discharge through a discharge passage 11, ports 13, 14, for connection to a fluid delivery and return circuit, a first fluid path from port 14 to the vicinity of passage 11, a second fluid path from the vicinity of passage 11 to port 13 and a spill valve 15, 16, 17, 18, in the first path, the valves being arranged so that with fluid supplied to port 14 the spill valve is opened by differential fluid pressures thereon and the tip valve is closed by differential pressure and the fluid returns to port 13, thereby providing a cooling flow through the injector, and with fluid supplied to port 13 the tip valve opens and the spill valve tends to close to promote fluid discharge through passage 11 but some fluid returning via the spill valve to port 14 and this returned portion being adjustable by means 20 acting on the spill valve. When the tip valve is closed the fluid flows from port 14 via spill valve orifice 21, and orifices 16<SP>1</SP> to the interior of spill valve piston member 16 and then via the interior of tip valve piston member 8, 9, through an annulus 22, swirl annulus 23, and passage 24 to port 13, the flow being in the reverse direction with the tip valve open and come of the flow swirled in annulus 23 passing through atomizer 3 and out of the passage 11. Differential fluid pressures act on piston member 8, 9 and 16 by communicating the pressure in passage 24 thereto by ports 26, 25, the incoming and outgoing fluid pressures acting on different piston areas to operate the valves in the manner required. With the tip valve open a piston 19 on member 16 engages an adjustable screw 20 to determine the opening between valve orifice 21 and valve seat 17 and thereby the returned proportion of fluid. Screw 20 may be set to close orifice 21 completely and to allow the tip valve to open in this condition, fluid in a space 28 acts as a dash-pot slowing down closure of the spill valve following changeover, by an external valve, of fluid supply from port 14 to port 13. The changeover valve, Fig. 2, may include means 53 whereby when the tip valve is closed, the flow of fluid through the injector can be adjusted independently of the flow when the tip valve is open. In an alternative injector, Fig. 3 (not shown), such means are included in the injector. A further injector, Fig. 4 (not shown), includes means permitting two different discharge rates through passage 11 when the tip valve is open, one rate being set by means corresponding to screw 20 in Fig. 1, and a second higher rate being selected by operating a piston- and-cylinder (89), (90) actuator to move a sleeve member (88) defining a spill valve orifice corresponding to orifice 21 in Fig. 1. A changeover valve, Fig. 2, for the injector of Fig. 1, comprises a hollow body with ports 32, 33 for connection to injector ports 13, 14 respectively, an inlet port 30 and an outlet port 31 and a valve member 37 carrying valve seats 38, 39, 43 and movable by compressed air acting on one side or the other of a piston 49. In the tip valve closed injector state, fluid passes from port 30, orifices 40, hollow stem 41 of member 37, to port 33 and from port 32 via orifices 35 to port 31. In the tip valve open injector state, the member 37 is moved so that its stem 41 is seated by an 0-ring 54 and so that orifice 35 is sealed from port 32 by valve seat 32, fluid passing directly from port 30 to port 32 and returning from port 33 via orifice 36, not now closed by seat 43, to port 31. Adjustment of a screw 53 moves seat 38 away from orifice 34 so that some of the flow by-passes the injector in the tip valve closed state, and passes directly from port 30 to port 31. The valve member 37 is dimensioned so that if the air supply acting on piston 49 fails, member 37 moves to the illustrated position thus placing the injector in its tip valve closed or shut down state.