US2524444A - Control valve - Google Patents

Description

Oct. 3, 1950 R. J. [FIELD 2,524,444 comer, VALVE Filed April 14, 1948 Patented Oct. 3 1950 CONTROL VALVE Richard Joseph Ifield, Exeter, New South Wales, Australia, assignor to Joseph Lucas Limited, Birmingham, England Application April 14, 1948, Serial No.

In Great Britain April 30, 1947 2 Claims.

In certain systems used for supplying liquid.

fuel to the combustion chamber or chambers of a jet-propulsion, turbine or other like internal combustion prime mover, there is employed a pump which is connected by a pipe system to a fuel discharge nozzle or nozzles in the said chamber or chambers, and it is desired to be able to regulate the rate of supply of liquid fuel to the nozzle or nozzles not only manually but also automatically in response to atmospheric-pressure conditions, so that the speed of the prime mover is substantially unaffected by variations in the said conditions. The object of the present invention is to provide improved means for enabling the above mentioned regulation to be obtained in a convenient and satisfactory manner.

In the accompanying drawing the single figure is a sectional elevation, more or less diagrammatic, of a regulating means constructed and arranged in accordance with the invention for controlling the supply of liquid from a pump to an internal combustion prime mover. 7

To elucidate the essential features of the invention I will first describe, with reference to the drawing, a known form of pump to which the invention is applicable. The pump comprises a rotary cylinder block I arranged in a casing 2 and having formed around its axis a plurality of bores 3 in each of which is arranged a reciprocatory plunger 4, the cylinder block i being adapted to be rotated by the prime mover (not shown) through the shaft element 5. During rotation of the cylinder block the plungers are moved in one direction by an angularly adjustable swash plate 6 and in the opposite direction by springs l, the latter serving also to hold one end of the block I in close contact with a valve seating 8 in the casing. In the valve seating are formed ports 8 8 which communicate respectively with a liquid fuel outlet 2 and a liquid fuel inlet 2 in the casing, the inlet being connected to any convenient source of liquid fuel supply (not shown). In one end of the casing is formed a hollow cylinder 9 having closed ends, and within the cylinder is arranged a piston Ill loaded by a, spring H. A rod I2 extending from the piston through one end of the chamber serves to adjust the obliquity of the swash plate for varying the output of the pump. The two ends of the cylinder 9 are in communication through a passage having a restricted orifice l3, and the end of the cylinder containing the spring (and remote from the piston rod) is provided with a vent l4. Liquid under pressure is admitted from the pump outlet 2 to the end of the cylinder opposite to the vent. When the vent is opened thereby allowing escape of liquid from the adjacent end of the cylinder, the liquid pressure in the other end causes the piston to move against the action of its loading spring in the direction for reducing the obliquity of the swash plate and thereby reducing the pump output. On closing the vent, the liquid pressure on the two sides of the piston becomes balanced, and the spring then moves the piston in the opposite direction causing the swash plate to be moved for increasing the pump output. One purpose for which the present invention is required is that of controlling the above mentioned vent l4, and one adaptation of the invention for that purpose will now be described.

Within a hollow regulator body part i5 is formed a liquid fuel passage leading from an inlet Hi to an outlet I! which are respectively intended to be connected to the pump outlet and the combustion chamber burner nozzle or nozzles. The pump outlet 2 is connectedto the said inlet i6 by a pipe i8. Between the inlet l6 and outlet I! there is formed in the pasage an arifice I 9, and the effective area of this orifice is variable by a slidable choke to create a variable pressure difference between the liquid at the inlet and the outlet. The choke consists of a hollow plunger 20 having the end which co-operates with the orifice shaped to a conical or other appropriate form, and a fixed conical member 2| co-operates with the bore of the said hollow plunger. The opposite end of the plunger 20 terminates in a piston 22 slidable in a cylindrical chamber 23 in the body part. One end of the chamber 23 communicates by way of a pasage 24 with a part 25 of the main fuel passage adjacent to the inlet l6, and the other end of the vided with a vent chamber 23 is propassage 26. The two endsof the chamber 23 are in communication by wayof in the a passage which is conventiently provided piston 22 and has within it a restricted orifice 21. The end of the chamber 23 which communicates with the passage 24 also communicates with the interior of the plunger 2|] through radial ports as 20 in the plunger.

. The vent passage 26 opens into a compartment 28 in the body part which can be connected to a sump or the pump inlet 2 by a pipe 29, and in this chamber is arranged a bell-crank lever 3|].

carrying on its short arm 3| a closure member 32 for the vent passage 26. The long arm 30 ot the lever is acted on by a pair of coaxial and opposed capsules 33 and 34, one of which (34) is evacuated and the other (33) of which is open to the atmosphere. Also the long arm of the lever is acted on by a pair 0. opposed and coaxial springs 35 and 36. One of these (35) is supported at one end in the compartment by an adjustable abutment 31. The opposite end of the other spring 36 is supported on a stem 38 which passes through the base of the compartment and bears on one side of the piston 22. The arrangement is such that variation of pressure in the atmospheric capsule 33 results in opening or closing of the vent passage 26. When the event is closed, the spring 36 moves the piston 22 in the direction for restricting the orifice l9 controlled by the choke. On the other hand opening of the vent allows liquid to escape from the one side of the piston 22, enabling the liquid pressure on the other side to move the piston in the direction for increasing the said orifice l9.

In communication with the compartment 28 above mentioned is arranged another compartment 39 containing another spring loaded valve lever 49 carrying at one end a closure member 4| which co-operates with a seating 42 around an outlet which is connected by a pipe 42 to the vent M of the pump controlling means above described. The lever 40 extends from this compartment into another, which is divided into two parts 43 and 44 by a spring-loaded diaphragm 45, the diaphragm having a stem 46 hearing on the end of the lever 40 opposite the one which carries the closure member 4|. The region 44 at one side of the diaphragm is connected by a passage 41 and thence by passage 24 to a point near the inlet |6 via the cylinder 23 which contains the choke piston 22, and the region 43 at the opposite side of the diaphragm 45 is connected by another passage 48 to a point near the outlet H. The diaphragm 45 is thus subject to a, liquidpressure difference determined and variable by the choke. When the pressure difference exceeds a predetermined amount it causes the associated vent valve 4| to be opened, thus causing the pump controlling means to reduce the rate of discharge of the pump.

In addition, there is arranged between the choke and the part 25 of the main fuel passage which communicates with the inlet IS. The throttle 49 co-operates with an annular or other appropriate seating 50 to vary the pressure difference created by the choke 20 between the liquid at the inlet l6 and outlet l1, and is connected by a spring to one arm 52 of a lever, which end is also adjustably connected by another spring 53 to the casing. The other arm 54 of the lever co-operates with a, manually operable cam 55 through a stem 56 passing through a wall of the casing. The same end of the lever arm 54 also abuts against one end of a capsule 51 the interior of which communicates with a passage 58 along which liquid is supplied from the pump by a pipe 59, the pressure of the liquid depending on the speed of the pump, and hence on the speed of the prime mover. This liquid may be supplied by a centrifugal pump formed by the rotary cylinder block I of the main pump. For this purpose the cylinder block is formed with an axial bore I which at one end communicates withythe inlet 2 through another port 8 in the seating 8, and at the other end communicates with a plurality of radial or like passages as in the cylinder block Liquid from the inlet 2 flows through the bore and is expelled by centrifugal action through the passages l into the interior of the casing 2 which communicates with the pipe 59. The arrangement is such that a throttle 49 t the throttle 49 can be moved towards and on to its seating for restricting the flow of liquid through the choke. Closing of the throttle 49 by the cam has the effect of increasing the pressure difference acting on the diaphragm 45, so causing the output of the pump to be reduced. Opening of the throttle is effected under the control of the cam 55 by the pressure fluid acting on the capsule 51. The purpose of the capsule is to effect the opening of the throttle at a controlled rate which is independent of the rate at which the cam is moved, thus obviating an excesively sudden increase in the flow of liquid in the event of the cam being suddenly moved from the idling to the full load position.

Thus in the operation of the regulating means according to the invention, the delivery of the pump through the pipe l8 to the outlet H to which the burner or burners are connected is controlled by the slidable choke plunger 20 which is variable by the action of the capsules 33 and 34 in response to changes of atmospheric pressure. These changes are caused to act upon the piston 22 connected to the slidable choke plunger by the opening or closing of the vent valve member 32 which controls the liquid pressure on the piston. The means for controlling the delivery of fuel by the pump or by other apparatus associated with the fuel supply system comprises the vent control valve member 4|, the opening or closing of which causes the stroke of the pump to be varied as previously described. This vent valve member is actuated by means responsive to the difference of liquid fuel pressure between the inlet and outlet of the regulating means, i. e. between the inlet l8 and the outlet l1. This means comprises the spring loaded diaphragm 45. Also the throttle 49 is arranged at the inlet side of the variable choke and may be closed by manually operable means, i. e. through operation of the cam 55, but is opened only by liquid pressure depending on the speed of the pump, acting through the capsule 51 for the purpose described above. The speed of the prime mover is initially determined by the setting of the cam 55 which limits the opening movement of the throttle 49, and the movement of the choke 20 ensures that the speed of the prime mover at any setting of the cam is substantially unaffected by variations in atmospheric-pressure conditions.

When the throttle 49 is closed, sufficient fuel to keep the prime mover idling flows to the outlet |1 through the passage 24 and the interior of the choke 20.

By this invention the required control of the liquid supplied to the burner or burners can be effected in a convenient and satisfactory manner. The invention is not, however, limited to the example described, as it may be utilised in other ways. Thus it may be used for controlling any appropriate variable delivery pump, or it may be used for controlling a valve in the delivery pipe between any convenient pump (of fixed or variable delivery) and the burner nozzle or nozzles, which valve may serve to throttle or to bypass the flow. Moreover, subordinate details of construction may be varied to suit different requirements.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. Regulating means comprising in combination a hollow body part having an inlet and an outlet for liquid fuel under pressure, a variable choke arranged between the inlet and outlet to create a pressure difference between the liquid at the inlet and outlet, a barometric device responsive to changes in atmospheric pressure, means for varying the choke under the control of the barometric device, a throttle arranged in series with the choke between the inlet and outlet to vary the pressure diiference created by the choke, manually operable means for closing the throttle, means responsive to fluid pressure for opening the throttle to an extent limited by the setting of the manually operable means. and liquid-pressure responsive means arranged to be exposed at one side to the liquid pressure at the outlet, and at the other side to the liquid pressure at the inlet.

2. Regulating means as claimed in claim 1 and having in combination a lever through which opening and closing movements are imparted to the throttle, a spring connecting the lever to the throttle, another to the bod RICHARD JOSEPH H'IELD. REFERENCES CITED UNITED STATES PATENTS 15 Number Name Date Udale Dec. 2, 1941 Jacobsson Mar. 9, 1943 Weiche Sept. 28, 11943 Ifleld Apr. 27, 1948

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