US3642028A

US3642028A - Metering valves

Info

Publication number: US3642028A
Application number: US865318A
Authority: US
Inventors: Raymond Evan Hufton; George Graham Morgan
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1968-10-17
Filing date: 1969-10-10
Publication date: 1972-02-15
Anticipated expiration: 1989-02-15
Also published as: JPS4815660B1; DE1952102C3; GB1274676A; DE1952102A1; DE1952102B2; SE345727B; FR2020931A1

Abstract

A fluid control valve has its port formed as an array of holes arranged both in radial rows and arcuate rows relative to an axis. A closure member has a platelike form and is displaceable about another axis by means of an actuator so as progressively to uncover the holes. The uncovering takes place as the actuator moves from a central position. There may be two hole arrays and the closure member is movable in either direction to uncover a respective one of the arrays. Alternatively the closure member is moved in one direction to uncover a single array, irrespective of the movement of the actuator from a central position. In either case the axis of the closure member is adjustable relative to the port, so that a desired rate of uncovering may be obtained for a given rate of actuator movement.

Description

United States Patent Hutton et al.

[ 1 Feb. 15,1972

METERING VALVES Inventors: Raymond Evan Hutton, Solihull; George Graham Morgan, Birmingham, both of England Assignee: Joseph Lucas (Industries) Limited, Birmingham, England Filed: Oct. 10, 1969 US. Cl ..137/625.3

Int Cl Field of Search ..251/5s, 205,208; 137/6253, l37/625.3l, 625.32

References Cited UNITED STATES PATENTS 3,342,449 9/1967 Jackson ..251/5s FOREIGN PATENTS OR APPLICATIONS 664,189 [/1952 GreatBritain ..25l/208 933,234 8/1963 GreatBritain ..25l/205 Primary Examinerl-lenry T. Klinksiek Attorneyl-lolman & Stern [57] ABSTRACT A fluid control valve has its port formed as an array of holes arranged both in radial rows andarcuate rows relative to an axis. A closure member has a platelike form and is displaceable about another axis by means of an actuator so as progressively to uncover the holes. The uncovering takes place as the actuator moves from a central position. There may be two hole arrays and the closure member is movable in either direction to uncover a respective one of the arrays. Alternatively the closure member is moved in one direction to uncover a single array, irrespective of the movement of the actuator from a central position. In either case the axis of the closure member is adjustable relative to the port, so that a desired rate of uncovering may be obtained for a given rate of actuator movement.

25 Claims, 14 Drawing Figures PATENIEUFEB 15 m2 SHEET 1 0F 6 INViENT AT FZ PATENTEDFEB 15 e912 3. 642 O28 SHEET 2 UF 6 YD v M AT Z SEN EYS PAIENTEUFEB 15 I972 3.642.028

sum 3 or 6 IO A11 AS PATENTEUFEB 15 I972 sum u UF 6 ATT ENEYS FIG. IO.

PATENTEDFEB 15 1972 3. 642.028

sum 6 0F 6 mm\ 0301; W 78 i0 ATT ENEYS METERING VALVES This invention relates to fluid control valves.

There is a requirement in certain gas turbine fuel control systems for a valve for producing a fluid pressure signal lying between two existing pressures such that the ratio of the signal pressure to the upstream or higher pressure should have a constant value over a predetermined range of movement of the control element of the valve and should increase linearly or substantially linearly with displacement of the control member outside said range in either direction. It is important, however, that the slopes of the parts of the characteristic of the valve for displacements outside the aforementioned range should be accurately set and difficulty has been experienced in manufacturing valves in which the required slopes can be accurately attained. Accordingly it has now been proposed to provide a valve in which adjustment of the slopes can be effected.

A fluid control valve in accordance with the invention comprises a body having an inlet and an outlet, a control element of platelike form angularly movable about an axis, an actuating means for moving the said control element, an element formed with port means and with which the control element coacts, the arrangement being such that when the actuating means is in a midposition the port means is closed by the control element, movement of the actuating means in either direction beyond a respective predetermined position causes the port means progressively to be uncovered, and means for adjusting the position of the axis of the control element relative to the port means so as to vary the rate at which the said progressive uncovering occurs.

Examples of the invention are illustrated in the accompanying drawings in which:

FIG. I is a longitudinal section through one embodiment of a valve;

FIGS. 2 to 6 are fragmentary sections taken respectively on lines 2-2, 3-3, 44, 55 and 66 in FIG. 1;

FIG. 7 is a fragmentary section on line 7-7 in FIG. 2;

FIG. 8 is a fragmentary section on line 88 in FIG. 1 with some detail omitted;

FIG. 9 shows, somewhat diagrammatically a section through an alternative form of valve;

FIG. 10 is a view on arrow 10 in FIG. 9 and with some parts removed;

FIG. 11 shows a valve port arrangement view in the direction of arrow 11 in FIG. 10; and

FIGS. 12 to 14 show details ofthe valve in FIGS. 9 and 10.

The valve shown includes a body formed from two

parts

10 and 11 to form a chamber 12. This chamber 12 has an inlet 13 formed in the part 12 coaxially with a spindle l5 rotatably supported by the part 1 1. The chamber 12 also has an outlet 14 in its wall. The spindle 15 has an integral control element 16 which is shown in more detail in FIGS. 4 and 5.

The control element 16 is of disclike form, although it is cut away on one side of the spindle 15 to provide clearance from other parts of the valve to be hereinafter described. The control element 16 which may, for example, conveniently be cast by the lost-wax process is formed with an internal cavity 17 which communicates with an inlet port 18 on the axis of the control element. As shown In FIG. 1 a bellows l9 sealingly mounted in the inlet 13 carries an annular sealing element 20 which is pressed against the control element around the port 18 to provide substantially fluidtight communication between the inlet 13 and the cavity 17.

The control element also has a pair of

openings

21, 22 in its opposite faces which communicate with the cavity 17. The opening 21 is in the face of the element 16 from which the spindle 15 extends. This opening is bounded by inner and outer arcuate edges 21a, 21b, of radii struck from the axis of the spindle 15, and radial edges 21c, 21d. The edge 210, is spaced by 5 from a datum line 16a of the element 16 and the edges 21c, 21d are spaced by 45, the angles being those subtended at the axis of the element 16. The opening 22 is of similar form, having

arcuate edges

22a and 22b and radial edges 22c and 2211. The edge 22c is 5 from the datum line 16a in the direction opposite the direction in which the edge 210 is spaced therefrom and the

edges

22c and 22d are 45 apart.

The control element 16 is sandwiched between a pair of

side plates

23, 24, the plate 23 lying against the face of the element 16 having the opening 21 and the plate 24 lying against the other face. The plate 23 has port means constituted by an array of drillings 25 which extend from the face of the plate 23 lying against the plate 16 into a recess 26 in the opposite face of the plate 23. This recess 26 communicates with the outlet 14. The drillings 25 are arranged in rows, which are radial with respect to an axis 23a lying at the center of a part-circular edge portion 23b of the plate, and in rows which extend in arcs about the axis 230. The outermost arcuate row lies on a radius measured from the axis 230 less than the radius of the edge 21b of the opening 21 in the element 16. The angular extent of the arcuate rows is 51. The position of the holes 25 is such that, in the off position of the valve, as shown, the holes all lie on the side of a datum plane including the datum line 16a and the axis of spindle 15 opposite the side of this plane on which the opening 21 lies. FIG. 2 indicates the position of the opening 21, relative to the drillings 25 when the valve is fully open in one direction.

The plate 24 is formed with a similar array of holes 27 opening into a recess 28 communicating with the outlet. The radius of the outermost row of holes 27 is the same as that of the outermost row of holes 25 in plate 23. The angular extent of the holes is 40. In the off position of the valve the holes 27 all lie on the side of the datum plane opposite the opening 22. FIG. 3 indicates the position of opening 22 with the valve in its other fully open position.

The

sideplates

23, 24 are carried respectively by a pair of

carrier plates

29, 30. Each carrier plate is mounted in the housing for angular adjustment about the axis of spindle 15. To this end, as 'shown in FIG. 6, each carrier plate (in the case shown, the carrier plate 29) has a lug 31 located between adjusting

screws

32, 33 screw-threadedly engaged in the wall of the body part 12. It will be appreciated that the carrier plate 29 can therefore be turned by slackening off one of the

screws

32, 33 and correspondingly tightening the other.

Each

sideplate

23, 24 is mounted on its associated carrier plate for rectilinear sliding movement in a direction perpendicular to the axis of the spindle 15. To this end each carrier plate has a cross-groove in which an integral tongue on the sideplate is engaged (see FIG. 8). For effecting adjustment of the

side plates

23, 24 relative to the

carrier plates

29, 30 there are a pair of adjusting screw mechanisms 34, 35. Each mechanism includes a screw 35a engaged with the body and screw-threadedly engaged with a nut 36 inside the chamber 12. This nut 36 engages one end ofa spring 37 the other end of which is engaged in a cup-shaped member 38 having a peg 39 thereon and which gives friction loading to prevent movement of screw 35a by vibration. This peg 39 extends into an arcuate slot 40 in a lug 41 on the associated sideplates 23 and 24.

The

carrier plates

29, 30 are spring-loaded towards one another by means of compression springs 42 which are engaged between the

body parts

10 and 11 and kidney-shaped recesses 43 in the

plates

29, 30. In addition each carrier plate has a pair of kidney-shaped through holes 44 which receive circular pressure pads 45 (see FIG. 7) which are directly engaged with the

sideplates

23, 24. Each pad 45 is urged against the associated sideplate by a spring 46 and, additionally, by a bellows 47 which receives the same fluid pressure as that present at the inlet 13.

The spindle 15 has an external lever 4 secured to it.

The valve described is intended for use in an air circuit of a fuel control system for a gas turbine engine. An air pressure signal is applied to this circuit and it is required to modify the air pressure in accordance with the angular position of the lever 4 which is coupled to the pilots throttle control. The circuit is such that the ratio of the pressure applied to the circuit to the pressure in the inlet 13 of the valve remains constant over a range of 10 of movement of the lever 4 and increases linearly when the lever is moved in opposite directions beyond this range. The valve described enables the end limits of the 10 range to be accurately set and also allows the slopes of the linear portions of the circuit characteristic to be accurately set.

Adjustment of the end limits is effected by angular displacement of the

sideplates

23, 24 using the adjusting screws 32, 33. It will be appreciated that turning the control element in a clockwise direction as viewed in FIG. 4 will produce no efiect on flow through the valve until the opening 21 starts to uncover the holes 25. Angular adjustment of the sideplate 23 will thus vary one end limit of the range. Similarly angular adjustment of plate 24 varies the other end limit.

Characteristic slope variation is obtained by lateral adjustment of the

sideplates

23 and 24 utilizing the screw mechanisms 34 and 35 respectively.

When the

plates

23 and 24 are in the positions shown in FIGS. 2 and 3 the slopes will be a minimum. Raising of the

plates

23 and 24 increases the effective radius of the holes and 27 from the true rotational center. Thus for a constant angular movement of lever 4, the actual chordal distance moved by the edges 21c, 22c across the

holes

25, 27 is increased thereby increasing the slope.

The angular extents of the arrays of

holes

25, 27 are larger than the angular widths of the

respective openings

21, 22 so that angular adjustment of the

plates

23, 24 does not interfere with full opening of the valve.

The valve arrangement shown in FIGS. 9 to 11 has a valve body 50 with an inlet comprising a fixed orifice 51. An outlet (not shown) is formed in the wall of the body 50. Mounted on fixed pivots 52 in the body 50 is a cam follower assembly 53 comprising a roller 54 carried on a wishbone-shaped structure 55. Also carried on the structure 55 are apair of

opposed abutments

56, 57. An extension 58 of the structure 55 carries a spring-loaded plunger 59.

The roller 54 engages a cam 60 which is mounted on a shaft 67 rotatable in the body 50. The cam 60 is formed of three

cam elements

68, 69, 70 shown in FIGS. 12 to 14. The cam element 70 is secured to the shaft 67 and has a part circular periphery 70a having its center on the axis of the shaft 67.

Elements

68, 69 have respective through

bores

68a, 69a and parts 68b, 69b of their peripheries formed to provide a constant rate of rise. The respective parts 680, 690 of the

elements

68, 69 are formed with a radius from the centers of the

bores

68a, 690 which is less than the radius of the periphery 70a of the element 70. The

elements

68, 69, 70 are assembled together and secured in their required relative positions by means of dowels passing through holes 71. The cam 60 thus has a dwell portion intermediate two constant-rise portions, and rotation of the cam 60 in either direction beyond the dwell portion will thus move the cam follower assembly 53 away from the shaft 67.

A lever assembly 61 is pivotally mounted on a stem 62 which is axially adjustable within the body 50.. The lever assembly 61 isengaged between the

abutments

56, 57 on the cam follower assembly 53 and includes an arm 63 and a flexible support member 64. Secured to the member 64 is a carrier 65 upon which is mounted a control element or blade 66 having a face lying against an adjacent portion of the body 50. The blade 66 is urged into close contact with the body 50 by the plunger 59. An adjustable abutment 72 on the arm 63 also engages the carrier 65. The stem 62 is adjustable by means of a sleeve 73 threadedly engaged with the body 50, and may be secured by means of a locknut 74. A bracket 75 is carried on the stem 62 and supports a spring assembly 76. The spring assembly 76 engages an arm 77 which forms part of the lever assembly 61 and which rotates therewith. The spring assembly 76 thus biases the lever assembly 61 in a clockwise direction as seen in FIG. 9, and via the abutment 57 urges the roller 54 against the cam 60.

Within the body 50 adjacent the blade 66 is an element 84 formed with a plurality of holes 78 which open into a chamber 79 within the body. The chamber 79 communicates with the inlet 51. The holes 78 are disposed, as shown in FIG. 11, in rows which are radial with respect to an axis 80 and which are also arranged in rows which extend in arcs about the axis 80. The location of the axis 80 is such that it is coaxial with the pivot of the lever assembly 61 in the central position of the said pivot. The holes 78 lie to one side of the datum line 81 which corresponds to a line passing along the edge of the blade 66 in a position of the blade 66 when the roller 54 is engaging the dwell portion of the cam 60. In this position, therefore, all the holes 78 are shut by the blade 66. The chamber 79 has a bleed orifice 82 controlled by a closure member in the form of a spring-loaded plunger 83. The plunger 83 is actuable by an edge cam 84a which is rotatable in the body 50.

In use the last-described embodiment is also used to modify an air pressure signal for a gas turbine engine fuel control system. The camshaft 67 is coupled to the pilots throttle control lever. Rotation of the cam 60 in either direction to lift the cam follower assembly 53 causes the abutment 57 to rotate the lever assembly 61 so as progressively to uncover the holes 78. Adjustment, by means of the sleeve 73 and stem 62, of the pivot position of the lever assembly 61 varies the distance between the said pivot and the abutment 57. Reduction of the said distance causes the blade 66 to have an increased displacement for a given displacement of the cam follower assembly 53. Increasing the said distance correspondingly reduces the displacement of the blade 66. The rate at which the holes 78 are uncovered may, for a given rate of cam rotation, effectively be varied. Movement of the pivot of the lever assembly 61 does not affect the bias applied by the spring assembly 76, since the stem 62 moves the spring assembly 76 via the bracket 75.

We claim:

1. A fluid control valve comprising a body having an inlet and an outlet, a control element of platelike form angularly movable about an axis, an actuating means on the body for moving the said control element, a ported element formed with port means and with which the control element coacts, means closing the valve when the actuating means is in a midposition, means moving in the actuating means in either direction beyond a respective predetermined position to open the port means progressively, and means adjusting the position of the axis of the control element relative to the port means so as to vary the rate at which the said progressive uncovering occurs.

2. A valve as claimed in claim 1 in which the. port means comprises a plurality of holes in the said ported element.

3 A valve as claimed in claim 2 in which the said holes are disposed in rows radial to the said axis of the control element.

4. A valve as claimed in claim 2 in which the said holes are disposed in rows extending in arcs about the said axis of the control element.

5. A valve as claimed in claim 1 in which the control element is of disclike form.

6. A valve as claimed in claim 1 in which the control element is formed with an opening adapted tobe aligned with the port means.

7. A valve as claimed in claim 6 in which the control element includes a passage by means of which the said opening communicates with the said inlet.

8. A valve as claimed in claim 6 in which the port means is formed in each of a pair of sideplates, the said sideplates being disposed on either side of the control element and in which the control element is formed with a pair of openings having a passage therebetween, each said opening being adapted to be aligned with the port means in a respective one of the sideplates.

9. A valve as claimed in claim 8 in which the sideplates have means for independent angular adjustment about the axis of the control element.

10. A valve as claimed in claim 8 in which the sideplates have means for independent rectilinear movement in a direction perpendicular to the axis of thecontrol element.

11. A valve as claimed in claim 8 in which the sideplates are urged towards each other by means of springs.

12. A valve as claimed in claim 8 in which the sideplates have means urging them towards each other .by resilient bellows subjected internally to a fluid pressure.

13. A valve as claimed in claim 8 in which the sideplates are each supported by carrier plates.

14. A valve as claimed in claim 13 in which the carrier plates have means urging them towards each other by means of springs.

15. A valve as claimed in claim 1 in which the control element is formed as a blade and is carried by a lever assembly, the pivot of the lever assembly forming the said axis of the control element.

16. A valve as claimed in claim 15 in which the said pivot is carried on a stem axially adjustable within the body.

17. A valve as claimed in claim 16 which includes a means for biasing the lever assembly in a direction to close the port means.

18. A valve as claimed in claim 17 in which the biasing means is a spring assembly which is supported by the said stem.

19. A valve as claimed in claim 15 in which the lever assembly is engaged by a cam follower assembly.

20. A valve as claimed in claim 19 in which the actuating means comprises a cam with which the said cam follower assembly coacts.

21. A valve as claimed in claim 20 in which the cam has a profile formed with a dwell portion intermediate two rise portions.

22. A valve as claimed in claim 21 in which the said dwell and rise portions. are formed as separate elements,

23. A valve as claimed in claim 19 in which the cam follower assembly is pivotally mounted in the body.

24. A valve as claimed in claim 19 which includes a means carried by the cam follower assembly for biasing the control element towards the element formed with port means.

25. A valve as claimed in claim 24 in which the said biasing means comprises a spring-loaded plunger.

Claims

2. A valve as claimed in claim 1 in which the port means comprises a plurality of holes in the said ported element.

3. A valve as claimed in claim 2 in which the said holes are disposed in rows radial to the said axis of the control element.

6. A valve as claimed in claim 1 in which the control element is formed with an opening adapted to be aligned with the port means.

10. A valve as claimed in claim 8 in which the sideplates have means for independent rectilinear movement in a direction perpendicular to the axis of the control element.

12. A valve as claimed in claim 8 in which the sideplates have means urging them towards each other by resilient bellows subjected internally to a fluid pressure.

22. A valve as claimed in claim 21 in which the said dwell and rise portions are formed as separate elements.