US2667918A - Means for effecting and controlling the supply of liquid fuel to prime movers - Google Patents

Description

Feb. 2, 1954 Filed April 20, 1948 R. J. IFIELD MEANS FOR EFFECTING AND CONTROLLING THE SUPPLY OF LIQUID FUEL TO PRIME MOVERS.

2 -Shaets-Sheet l 33 4 0 H 19 #13 x 20 l III Fb. 2, 1954 R. J. IFIELD 2,667,9 8

MEANS FOR EFFECTING AND CONTROLLING THE SUPPLY OF LIQUID FUEL TO PRIME MOVERS Filed April 20, 1948 2 Sheets-Sheet-Z 'Zl a 4 I l v 12 f) 5,; '12. I A fm Fig.3

2 zmzaivr 55 51 flLJi fi/ldz (@M @Qaw Patented Feb. 2, 1954 MEANS FOR EFFECTING AND CONTROLLING THE SUPPLY OF LIQUID FUEL TO PRIIVIE MUVERS Richard Joseph Ifield, Elouera Exeter, New South Wales, Australia, assignor to Joseph Lucas Limited, Birmingham, England Application April 20, 1948, Serial No. 22,058

Claims priority, application Great Britain May 3, 1947 7 Claims. (Cl. 158-363) This invention has for its object to provide improved means for effecting and controlling the supply of liquid fuel to the combustion chamber of a jet-propulsion, turbine, or other prime mover.

In the accompanying drawings:

Figure 1 is a sectional elevation, more or less diagrammatic, of means or apparatus constructed in accordance with the invention for effecting and controlling the supply of liquid fuel to the combustion chamber of a jet-propulsion, turbine, or other prime mover;

Figure 2 is a similar View of a modified arrangement of the above means or apparatus.

Figure 3 is a similar view of a further modified arrangement.

In carrying the invention into effect according to one convenient mode as shown in Figure 1, there is provided a suitable housing l containing a rotary radial-flow centrifugal pump having an impeller 2 mounted on a shaft 3, the delivery pressure of the pump being proportional to the square of the speed of the impeller. A liquid fuel supply passage 4 in the housing leads to the centre of the pump impeller, and another passage 5 in the housing also communicating with the centre to an outlet 8 which is adapted to be connected by a pipe to the burner in the combustion chamber. In this passage is arranged a choke for controlling the quantity of liquid which can pass to the outlet.

The choke comprises a conical or like stem 9" co-operating with an annular throat H3 in the housing, the said stem being formed on or secured to a plunger H which at the end remote from the choke has formed on or secured to it a piston 12 slidable in a cylindrical chamber 53 in the housing. One end of this chamber communicates by way of a passage l t with the side of the choke 9 adjacent to the pump. The other end of the said chamber communicates by way of another passage i5 with a vent l5 forming the seating of a spring loaded and pivoted control valve ll which is responsive to barometric and liquid pressure conditions, and also with the first mentioned end of the said chamber it by way Y the pump inlet passage by a passage 22, and in 2 this chamber are contained a pair of coaxial capsules 23 and 24, the interior of one of which (23) is evacuated, and the interior of the other 2 being opento the atmosphere by way of apassage 25. Between the capsules is connected the outer end of the long arm 26 of a bell crank lever which is loaded at opposite sides by a pair of coaxial springs 21 and 28. One end of the spring 21 is supported adjustably by a bolt 29 in the housing, and the opposite end of the spring 23 is supported by a stem 30 which rests on one side of the piston l2 above mentioned. The short arm 3! of the lever is arranged to act on one end of the lever I 9 and to impart an opening movement to the control valve [1.

Adjacent to the other end of the control valve lever IS, the chamber containing the valve is separated from another chamber 32 by a flexible diaphragm 33 which is loaded by an adjustable spring 34 contained in the latter chamber 32 and has formed on or secured to it a stem 35 acting on the valve lever. This second chamber 32 is in communication with the pump side of the choke 9 by way of a passage 35 in which is formed a restricted orifice 31, and between this orifice and the said chamber is provided a bypass passage 38 leading to the valve chamber, this passage being controlledby an adjustable regulator whereby a liquid pressure difference can be set up at the opposite sides of the diaphragm. The regulator consists in one form of a spring loaded stem 39 movable by a cam 40 which is operable by the attendant, the stem 39 pendent actuation by the said devices.

The mode of operation of the apparatus above described is as follows:

The pump which is driven from any convenient source of motion, supplies liquid fuel to the outlet 8 through the choke. Normally the control valve l! is closed, and the choke 9 is locked against movement by the liquid entrapped between the one side of the piston l2 and the valve ii. In the event of a change of barometric .pressure, due for example, to a change of altitude, necessitating a reduction in the amount of fuel delivered by the pump, the change of pressure in the capsule 24 permits the spring loading on the valve lever 26 to impart an openin the pressure difierence acting upon the diaphragm 44 will result in a movement of the balanced valve 42 to maintain the flow..at a constant value. As previously mentioned, if the diaphragm 33 is retained as in the arrangement illustrated, this will prevent an increase in speed beyond a selected or predetermined limit by openingthe valve l7 when such limit is exceeded.

In a further mode of carrying the invention into effect .as shown in Figure 3, the general arrangement is similar to that of Figure 1, the

-. same reference numerals being used to denote cause the valve I! to be opened and allow the choke 9 to be moved for reducing the flow through the outlet. The amount of pressure difference acting on the diaphragm is under thecontrol of the regulator 39 which is operable by the attendant, and consequently the rate of supply of the liquid to the burner can also be varied by him to suit idiiferent requirements.

When .it is required that the quantity of "fuel supplied by the pumpshall remain substantially constant for any given setting determined :by the barometric device, the modified mode of carrying the invention into eflect shown in Figure 2 may be employed. The arrangement is generally similar to that shown in Figure -1 and similar parts are given the same reference numerals. Between the outlet passage 1 from the pump impeller 2 and the choke 9 in the outlet passage 8 there is provided a second choke in the form of a balanced valve which serves to control the flow between these two points. A

pair of val-veheads 42 are carried on a stem lator 39 shown in Figure 1 is omitted and the chamber 32 of diaphragm 33 is connected directly to the cylinder 43 by a passage 48, the said cylinder being also in communication with the delivery side of the centrifugal pump by a passage 49. In thismodification the speed regulating device comprising the diaphragm -33 which is responsive to liquid pressure difierence may be omitted if desired, excepting when it is also desired to limit the maximum-speed of the-prime mover, in which case it is retained as shown in Figure '2.

In the operation of this arrangement, the pump impeller 2 supplies liquid fuel to the outlet "8 through the two chokes comprising the balanced valve 42 andthechoke member-9. Normally-the control valve H is-closedandthe choke 9 is locked against movement by the liquid entrapped between one side of the piston 12 and the valve H. In the event of :a change of barometric pressure which necessitates for example a reduction in the amount of fuel delivered by the pump, the change-'of pressure the capsule 24 permits the spring loading on the valve lever 25 to impart an opening movement to the valve l7. Liquid pressure actingon the piston l2 can now move the piston in the direction for restricting the flow ,past the choke 9 until the liquid fuel supply is suitably adjusted. If, owing to fluctuation in the speedof the pump impeller 2 the quantity of :fuel "supplied by the .pump should vary for any given setting of the choke 9 as above described, theiconsequentlal variation .similar parts, but the pressure difference applied to the diaphragm which effects the speed control is obtained by tapping the centrifugal pump at different radial positions. Referring V. to the drawing, the housing I contains the pump impeller 2 on a shaft 3, the fuel being supplied to th'e-centre of the impeller by a passage 4 and excess being returnedby a passage 5. A chamrber 6 surrounding the impeller communicates resting on the piston 12.

by a pipe 1 to a throat H) controlled by a choke :9 and thence to an outlet 8 which is adapted to be connected to the burner or burners in the combustion chamber of the prime mover. The choke :9 is formed on or secured to a plunger ll secured to a :piston I2 slidable in acylinder13. A passage l4 connects one end of the cylinder 1-3 to the side of the choke adjacent to the pump. The other 'end of the cylinder l3 communicates by a passage l5 to the seating of the valve H. A restricted orifice i8 is provided in the piston l2 andthe valve I l iscarried bya lever 19 loaded by a spring '26. The 'control '-valve I! is located in a chamber 2| communicating with the pump inlet by a passage '22,.and the said chamber also contains an evacuated capsule -23 and a similar capsule 24open to atmosphere. A long arm 26 of a bell crank lever is connected between the capsules and is loaded by coaxial springs 2-1 and 28. The spring :28 is supported by a stem 39 The short arm 3! of the bell cran'k lever acts on the lever 19 of the control valve H. A flexible diaphragm 33 loaded by a-n-a'djustable spring 34 has a stem '35 acting on the lever IS. The chamber -32 on one side of the diaphragm 33 is connected bya passage 5il to a chamber '5! communicating with a paspeller -2.

sage :52 ina movable wall 53 forming partof one side of the chamber containing the pump im- The ,passage'52 communicates with a port '54 in the wall and the latter is movable radially by means of a manually operable pinion 55 engaging a rack 56 formed in the wall 53. Thus byadjusting the Wall 53 radially the pressure communicated to the chamber 32 of the diaphragm33 may be varied, the pressure acting -The invention is not however, restricted to the examples described, as subordinate details of construction or arrangement 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. Means for effecting and controlling the supply of liquid fuel to a prime mover, comprising the combination of a centrifugal fuel pump whose delivery pressure is a function of its speed, an outlet for liquid fuel delivered by the pump, a variable choke located between the delivery side of the pump and the outlet, a cylinder communicating at one end with the delivery side of the pump and provided at the other end with a vent, a spring loaded piston united with the choke and slidable in the cylinder to vary the choke and thereby vary the fuel flow past the choke, a restricted passage interconnecting the spaces in the cylinder at opposite sides of the piston, a valve for controlling the cylinder vent, means responsive to barometric pressure for actuating the valve and thereby permitting movement of the piston, a second choke located between the delivery side of the pump and the first mentioned choke, a spring loaded member for varying the second choke in response to a liquid pressure difference created by the first choke, and manually operable means acting on the spring loaded member for regulating the said pressure difference.

2. Means for effecting and controlling the supply of liquid fuel to a prime mover, comprising the combination of a centrifugal fuel pump whose delivery pressure is a function of its speed, an outlet for liquid fuel delivered by the pump, a variable choke located between the delivery side of the pump and the outlet, a cylinder communicating at one end with the delivery side of the pump and provided at the other end with a vent, a spring loaded piston united with the choke and slidable in the cylinder to vary the choke and thereby vary the fuel flow past the choke, a restricted passage interconnecting the spaces in the cylinder at opposite sides of the piston, a valve for controlling the cylinder vent, means responsive to barometric pressure for actuating the valve and thereby permitting movement of the piston, a spring loaded member responsive to a liquid pressure difference for initiating movement of the piston to vary the choke independently of barometric pressure, a passage through which one side of the said member is posed to the pressure of liquid delivered by the pump, a second passage through which the other side of the said member is exposed to the inlet side of the pump, and manually operable means for varying the radial position at which the delivery side of the pump communicates with the first passage for regulating the liquid pressure difference acting on the said member.

3. Means for effecting and controlling the supply of liquid fuel to a prime mover, comprising the combination of a centrifugal pump whose delivery pressure is a function of its speed, an outlet for liquid fuel delivered by the pump, a variable choke located between the delivery side of the pump and the outlet, a cylinder communicating at one end with the delivery side of the pump and provided at the other end with a vent, a spring loaded piston united with the choke and slidable in the cylinder to vary the choke and thereby Vary the fuel flow past the choke, a first restricted passage interconnecting the spaces in the cylinder at opposite sides of the piston, a valve controlling the cylinder vent, means responsive to barometric pressure for 6 actuating the valve and thereby permitting movement of the piston, a spring loaded member responsive to a liquid pressure difference for initiating movement of the piston to vary the choke independently of barometric pressure, a second restricted passage through which one side of the said member is exposed to the pressure of liquid fuel delivered by the pump, a by-pass passage communicating with said second restrictpassage and with a space at the other side of the said member, and manually operable means for controlling the liquid flow through the bypass passage so that the said member is subjected to a liquid pressure difierence determined by the manually operable means.

4. Means for effecting and controlling a liquid fuel supply according to claim 3, in which the valve controlling the cylinder Vent is normally closed so that the choke is locked against movement by the liquid entrapped between the one side of the piston and the said valve.

5. Means for effecting and controlling a liquid fuel supply according to claim 1, in which the valve controllin the cylinder vent is normally closed so that the choke is locked against movement by the liquid entrapped between the one side of the piston and the said valve.

6. Means for effecting and controlling a liquid fuel supply according to claim 2, in which the valve controlling the cylinder vent is normally closed so that the choke is locked against movement by the liquid entrapped between the one side of the piston and the said valve.

7. Means for effecting and controlling the supply of liquid fuel to a prime mover, comprising the combination of a centrifugal pump whose delivery pressure is a function of its speed, an outlet for liquid fuel delivered by the pump, a variable choke located between the delivery side of the pump and the outlet, a cylinder communicating at one end with the delivery side of the pump and provided at the other end with a vent, a spring loaded piston united with the choke and slidable in the cylinder to vary the choke and thereby vary the fuel flow past the choke, a restricted passage interconnecting the spaces in the cylinder at opposite sides of the piston, a valve controlling the cylinder vent, means responsive to barometric pressure for actuating the valve and thereby permitting movement of the piston, means for actuating the valve to cause the fuel flow past the choke to be varied in response to a liquid pressure difference dependent upon the outlet pressure of the pump, and manually operable means for regulating the said liquid pressure difference.

RICHARD JOSEPH IFIELD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,136,959 Winfield Nov. 15, 1938 2,384,282 Chandler Sept. 4, 1945 2,405,888 Holley Aug. 13, 1946 2,456,604 Barfod et a1. Dec. 14, 1948 FOREIGN PATENTS Number Country Date 592,769 Great Britain Sept. 29, 1947

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