US3741237A

US3741237A - Fluid control valves

Info

Publication number: US3741237A
Application number: US00133152A
Authority: US
Inventors: J Browne
Original assignee: Sandall Precision Co Ltd
Current assignee: Sandall Precision Co Ltd
Priority date: 1970-04-27
Filing date: 1971-04-12
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26
Also published as: CA933840A; DE2119803A1; BE766380A; SE371279B; DE2119803C3; FR2086386B1; ZA712354B; GB1309126A; FR2086386A1; JPS5025993B1; DE2119803B2

Abstract

A fluid control valve has a spool located in a bore for controlling the flow of fluid from an inlet pressure port to outlet ports depending on the position of the spool. In the embodiments described and illustrated a proportion of inlet fluid pressure is used to rotate the spool and to move the spool in the bore.

Description

United States Patent [191 Browne FLUID CONTROL VALVES [75] 'lnventor: John Patrick Browne, Bletchley,

Bnckinghamshire, England [73] Assignee: Sandall Precision Company Limited, Bletchly, Buckinghamshire, England [22] Filed: Apr. 12, 1971 [21] Appl No.: 133,152

[30] Foreign Application Priority Data Apr. 27, 1970 Great Britain 20,083/70 [52] US. Cl 137/332, 91/3, 137/83, 137/468, 137/625.61, l37/625.63, 137/625.64

[51] Int. Cl. F15b 5/00, Fl6k 29/02 [58] Field of Search 137/331, 332, 625.63, 137/625.64; 91/3, 430

v 1 References Cited UNITED STATES PATENTS 2,359,017 9/1944 Balsiger 137/332 June 26, 1973 2,664,097 12/1953 Parker 137/332 2,896,654 7/1959 Gnzmann 137/83 3,473,547 10/1969 Coakley 137/625.63 X 3,205,782 9/1965 Tourtellotte 137/83 X Primary Examiner-Martin P. Schwadron Assistant Examiner-Richard Gerard Attorney-Larson, Taylor and Hinds [57] ABSTRACT A fluid control valve has a spool located in a bore for controlling the flow of fluid from an inlet pressure port to outlet ports depending on the position of the spool. In the embodiments described and illustrated a proportion of inlet fluid pressure is used to rotate the spool and to move the spool in the bore.

8 Claims, 15 Drawing Figures PATENTEDJUNZB ms SHEET t 0F 7 W @UK v Tm PAIENIEDJUN 26 973 SHEET 6 OF 7 NTOE PATENTEU JUN 26 4915 SHEEI 7 OF 7 Lsmq.

FLUID CONTROL VALVES This invention relates to fluid control valves, and more particularly to such valves incorporating a spool for controlling fluid.

It is an object of the present invention to provide a fluid control valve capable of operation with a good reliability and a low threshold in environmental conditions where the level of fluid contaminent may be relatively high.

It is a further object of the invention to provide such a valve in which maintenance requirements are at a minimum and servicing is a relatively simple task.

According to the invention I provide a fluid control valve including a spool for controlling the flow of pressurised fluid from an inlet port to at least one outlet port, wherein a proportion of inlet fluid pressure is used to rotate the spool.

The inlet fluid pressure may also be used to cause longitudinal movement of the spool.

In another form of the invention I provide a fluid control valve having a body, a sleeve fixedly secured in the body and a spool located in a bore in the sleeve, a

chamber in the sleeve at each end of thespool, inlet and outlet ports in the body communicating with ports in the sleeve and annular chambers formed between a plurality of heads on the spool, the heads being arranged so that the axial position of the spool controls the flow of fluid through the valve, wherein first means are provided for continuously rotating the spool when pressurized fluid is supplied to the inlet port and second means are provided for varying fluid pressure being supplied to the chamber at each end of the spool.

The invention will now be described by way of example only with reference to the accompanying drawings, in which:

FIG. 1 is a part sectional view through a fluid control valve showing one embodiment of the invention,

FIG. 2 is a sectional view on lines A-A of FIG. 1 and lines 13-13 of FIG. 6,

FIG. 3 is a sectional view on lines B--B of FIG. 1,

FIG. 4 is a non-sectional view of the area of the spool enclosed within the circle C on FIG. 1,

FIG. 5 is a view on arrow D of FIG. 4, FIG. 6 is a part sectional view through a fluid control valve showing another embodiment of the invention,

FIG. 7 is a sectional view on lines F-F of FIG. 6,

FIG. 8 is a non-sectional view of the area of the spool enclosed within the circle G on FIG. 6,

FIG. 9 is a view on arrow H of FIG. 8,

FIG. 10 is a sectional view on lines J.] of FIG. 6,

FIG. 11 is a sectional viewtaken on lines K-K of FIG. 10,

FIG. 12 is a sectional view showing a modification of the valve shown in FIGS. 1 and 6,

FIG. 13 is a part sectional view on lines LL of FIG. 12,

FIG. 14 is a graph to explain a particular feature with relation to FIG. 13, and

FIG. 15 is a non-sectional view showing a further modification of the valve shown in FIGS. 1 and 6.

Referring now to FIG. 1, a spool generally indicated at 11 having

heads

12, 13, 14, 15 and 16, is located in the bore of a sleeve 49 fixedly secured in a valve body 17. Each end of the bore is sealed by a cap 50 secured by bolts 51.

Annular chambers

52, 53, 54 and 55 are formed on the sleeve 49 and communicate through

ports

56, 57, 58 and 59 respectively with

annular chambers

22, 25, 26 and 23 formed between the heads on the spool 11. The width of heads 13 and 15 is such that when the spool is in the neutral position as shown in FIG. 1 the metering edges of the heads overlap the edges of two ports 60 and 61 sufficient to block the passage of fluid. The ports 60 and 61 communicate through two annular chambers 62 with ports 18 and 19 respectively formed in the body 17. Two ports 20 and 21 formed in the body 17 communicate with

annular chambers

52 and 55 respectively. A pressure port 24 is connected through a branch duct with annular chambers 53 and 54.

In the valve of FIG. 1, two orifices 27 extend into the head 14 from the end adjacent the chamber 25. The orifices 27 extend in a direction initially substantially parallel with the longitudinal axis of the spool to approximately half way through the head then through 90, in substantially the same plane but in opposite directions, to communicate with two chambers 28 formed around the centre of the head 14 and best shown in FIGS. 3,

. 4 and 5. From FIG. 3 it will be seen that the orifices 27 are located in bosses 29 in the head 14 and communicate one to each of the two chambers 28. Reference to FIGS. 4 and 5 will show that the bosses 29 extend between two

heads

30 and 31 formed on the outer edges of head 14, the

heads

30 and 31 serving to isolate the chambers 28 from the

chambers

25 and 26. The chambers 28 communicate through threeradially disposed orifices 32 with an annular chamber 33 formed in the sleeve 49 (FIG. 3).

A conduit 34 connects the chamber 33 through a pressure reducer 35 to a jet pipe assembly 36 which includes a static transfer jet 109 and a deflecting jet 37 suspended from a torque tube 38 and located in a chamber 39 formed in the body 17. The chamber 39 is connected to a fluid reservoir (not shown). The deflecting jet 37 terminates in a jet nozzle 110 and is offset laterally from the centre line of a splitter disc 40 formed in the head 16 on the spool 11 (FIGS. 1 and 2). Two

annular receiving chambers

41 and 42 are formed one on each side of the splitter disc 40.-Receiving chamber 41 communicates through an orifice 43 in the splitter disc 40 and a bore 44 in one end of the spool with an actuating chamber 45 formed between the cap 50 and the end surface of the spool 11. Receiving chamber 42 communicates in a similar manner through orifice 46 and bore 47 with an actuating chamber 48 formed between the second cap 50 and the opposite end of the spool 11.

The pressure reducer 35 in the valve of FIG. 1 is in the form of a series of orifice plates.

The embodiment of the valve shown in FIG. 6 is similar to that previously described except for a rearrangement of the ports on the spool and a modified pressure reducer, and similar elements have been given the same numbers with primes attached.

In the valve of FIG. 6, two orifices 27' extend into the head 14 from the end adjacent the chamber 25' at an angle to the longitudinal axis of the spool 11', then at in opposite directions to communicate with a continuous annular chamber 63 formed in the head 14' and best shown in FIGS. 7, 8 and 9. The chamber 63 communicates through three radially disposed orifices 32' with an annular chamber 33' formed in the sleeve 49' (FIGS. 6 and 7). A conduit 34' connects the chamber 33 through a pressure reducer 35' to a jet pipe assembly 36. It will be apparent that in this embodiment the splitter disc 40 and the two annular receiving chambers 41' and 42 are also located in the head 14' which is located centrally of the spool 11. The pressure reducer 35' is in the form of a one-piece frustoconical unit shown in more detail in FIGS. and 11.

With reference to FIGS. 10 and 11, an inlet orifice 64 connects the upstream end of a tapered body 98 to an inlet chamber 65, which is connected through a series of orifices 66 located in the walls of chambers located circumferentially of the body 98 to an outlet chamber 67. The outlet chamber 67 is connected via an orifice 68 to the downstream side of the reducer 35'.

FIG. 12 shows details of a modification which can be incorporated into either of the valve arrangements previously described which provides a pressure and temperature compensated reducer.

A sleeve 69 is fixedly secured in a bore 70 in the body 17. A compensating spool 71 is slidably mounted in a bore in the sleeve 69 and is fixed at its upperend to an aluminium rod 72. The rod 72 extends through a clearance bore in the spool 71 and is connected at its lower end to a piston 73 slidably mounted in a bore 74 which is closed by a cap 75. The bore 70 is closed by a cap 76. A coil spring 77 is located in a chamber 78 between the end of the first sleeve 69 and a disc 79 which abuts the upper edge of the piston 73. Diametrically opposed ports 80 formed in the sleeve 69 communicate with annular chambers 89 on the spool 71 of identical pitch to the ports 80. An inlet port 81 in the sleeve is connected by a passage 82 in the body 17 to the annular chamber 33 (FIG. 3) and 33 (FIG. 7), and an outlet port 83 is provided at the opposite end of the sleeve. Bore 74 is connected by a passage 84 to the pressure port 24 and the chamber 78 is connected to a fluid reservoir (not shown). Orifices 85 are provided in the walls of the spool 71 and a flange 86 having orifices 87 is provided at its upper end and located in a chamber 88 formed in the bore 70 between the end of the fixed sleeve 69 and the cap 76. I

FIG. 12 also shows a modification of the jet pipe assembly previously described. Outlet port 83 communicates with a bore 90 formed in one end of a housing 91 rotatably positioned in a bore 92 in the body 17. The other end of the housing is supported in the bore of a retainer 93 secured in the body 17 by bolts 94. The bore 90 extends through an angle of 90 into a deflecting jet 95 formed on the housing and teminates in ajet nozzle 110 located in a chamber 111 and positioned above a splitter disc 40 formed on the spool 11 as previously described. The chamber 111 is connected to a fluid reservoir (not shown). One end of a torque tube 96 is fixed in the housing 91, the other end protruding through a retainer 97 for connecting to a suitable torque motor (not shown). A projection 99 is formed on the housing 91 diametrically opposite the deflecting jet 95 and is located in a chamber formed between the walls of the body 17 and the retainer 93. In FIG. 13 it will be-seen that due to the mass of the projection 99 opposite the deflecting jet 95 the centre of gravity 108 of the assembly is located above a pivot point 107.

In FIG. a jet nozzle 100 is shown located above a splitter disc 101 formed on a spool 106, in a similar manner to that previously described. In this embodiment, however, the

edges

102 and 103 of two fluid receiving

chambers

104 and 105 are of complementary sinusoidal shape as opposed to the straight edges of the chambers in the embodiment of FIGS. 1 and 6.

In operation of the valve shown in FIG. 1, pressurized fluid applied to the pressure port 24 flows into the annular chambers 53 and 54 and through the ports 57 and 58 into the

annular chambers

25 and 26. The fluid passes into the orifices 27 and ejects into the chambers 28 (FIGS. 1 and 3) or chamber 63 (FIGS. 6 and 7). In both cases this arrangement provides, in effect, a balanced fluid jet motor in an isolated portion of the spool and provides energy to impart rotation to the spool 11 within the bore of the sleeve 49.

Utilization of this energy reduces the pressure of the fluid which now flows through the orifices 32, the annular chamber 33 and the conduit 34, and is further reduced in the pressure reducer 35 to a level suitable for use in the jet pipe assembly 36.

The fluid flows through the deflecting jet 37 and issues from the jet nozzle to impinge on the edge of the splitter disc 40 (FIG. 2) so that the jet reaction force on the spool contributes an additional torque in the same sense as the fluid jet motor.

When the nozzle 1 10 is directly above the edge of the splitter disc 40 the fluid flows at equal pressures into each of the receiving

chambers

41 and 42 and through the orifice 43 of bore 44 and orifice 46 and bore 47 respectively to the

actuating chambers

45 and 48 located at either end of the spool, thus providing a positional servo-mechanism which controls spool displacement. As shown in FIG. 1, with the jet nozzle 110 issuing directly onto the edge of the splitter disc 40, the fluid pressures in actuating

chambers

45 and 48 are equal and the spool is continuously rotated and maintained in the neutral position shown in FIG. 1 with the heads 13 and 15 blocking the ports 60 and 61, to prevent any of the input fluid pressure in

chambers

25 and 26 from flowing through annular chambers 62 to ports 18 and 19. Surplus fluid is returned to a reservoir (not shown) through the chamber 39.

Displacement of the spool in the bore of the sleeve is accomplished as follows. If it is desired to move the spool to the left as viewed in FIG. 1, the jet nozzle 110 of the deflecting jet 37is swung by the torque tube 38 also to the left to cause more fluid to enter receiving chamber 42 than enters chamber 41, resulting in an increase of fluid pressure in actuating chamber 48. Excess fluid in actuating chamber 45 exhausts through the bore 44, the orifice 43 and receiving chamber 41, to mix with surplus fluid returning to the reservoir through the chamber 39. The increased fluid pressure in chamber 48 acts on the area of the spool 11 and results in the continuously rotating spool 11 being displaced to the left in the bore of the sleeve 49. This movement uncovers ports 60 and 61 to allow a flow of fluid from the input fluid pressure in chamber 26 to the port 19, and also provides communication between ports 18 and 20. Movement of the spool to the right as viewed in FIG.- 1 is accomplished in a similar manner by swinging the deflecting jet 37 to the right to increase the fluid flow into receiving chamber 41, and therefore increasing the pressure in actuating chamber 45, and decreasing the fluid flow into receiving chamber 42, which results in a decrease in fluid pressure in actuating chamber 48. Displacement of the spool 11 to the right from the position shown in FIG. 1 allows a flow of fluid from the input fluid pressure in chamber 25 to the port 18, and also provides communication between ports 19 and 21.

In one application the valve of the present invention may form part of a hydraulic system in which the pressure port 24 is connected to a source of high pressure fluid, for instance, oil pumped from a reservoir. Ports 20 and 21 are connected to the reservoir, and ports 18 and 19 are connected to a reversible hydraulic motor which could be of either the reciprocating or rotating type. Axial displacement of the spool, therefore, provides variable area orifices between heads 13 and and ports 60 and 61 respectively, to control direction, pressure and/or volume of fluid flowing from the pressure port 24 to the motor through either of the ports 18 or 19. The area of the orifices is determined by the displacement of the spool from the neutral position, this displacement being a function of the differential pressure in actuating

chambers

45 and 48 which is proportional to movement of the deflecting jet 37 from its neutral position.

The valve of FIG. 6 operates in a similar manner to that previously described. Inlet fluid pressure is ejected from the orifices 27' into the chamber 63 (FIGS. 6, 7, 8 and 9) to impart continuous rotation to the spool 11' in the sleeve 49. The fluid flows through the orifices 32', the annular chamber 33' and the conduit 34', and is further reduced in the pressure reducer 35' to a level suitable for use in the jet pipe assembly 36'.

In the valve of FIG. 1 the fluid flowing through the series of orifice plates in the pressure reducer 35 reduces the pressure to a suitable level for use in the jet pipe assembly. In the valve of FIG. 6 the fluid enters the tapered body 98 of the pressure reducer 35' through the inlet orifice 64 (FIGS. 10 and 11) to an inlet chamber 65. The fluid flows through the series of orifices 66 to an outlet chamber 67, then through the orifice 68 at suitably reduced pressure to the jet pipe assembly 36'. The force necessary for operating the torque tube 38 (FIG. 1) or 96 (FIG. 12) may be derived from any suitable source and may, for instance, be in the form of a torque motor. The motor may be operated from a mechanical, fluidic, hydraulic, electric or electromagnetic source.

One set of typical valve operating pressures may be as follows: system (inlet) pressure 3,000 p.s.i.; outlet pressure from fluid jet motor 2,600 p.s.i.; outlet from pressure reducer 200 p.s.i.

In a system where the fluid temperature is controlled and the system pressure supply is sensibly constant, then either of the pressure reducer arrangements previously described will be more than adequate to maintain a relatively constant fluid pressure to the jet pipe assemblies. However, as the magnitude of the fluid pressure in the actuating chambers at either end of the spool is a proportion ofthe jet pipe pressure, and if the only control of the jet pipe pressure relies on a fixed orifice, whether it be single or a series, then any decrease in the system (inlet) pressure will result in adecrease in jet pipe pressure with a resultant loss of dynamic performance. A similar loss of performance could result from pressure losses caused by a corresponding increase in fluid viscosity due to a fall in fluid temperature below the design temperature. To ensure that the valves of the present invention function well in universal applications, incorporation of the modification shown in FIG. 12 into the valve shown in either FIG. 1 or FIG. 6 will provide an automatic temperature and pressure compensated pressure reducer arrangement, which will provide a relatively constant outlet pressure regardless of fluctuations in the pressure and temperature of the inlet fluid.

The arrangement of FIG. 12 overcomes the limitations due to a fall in jet pipe pressure by ensuring that the area of each orifice in the reducer varies inversely as the square root of the pressure change and increases due to a fall in fluid temperature.

In FIG. 12 the modification is shown in an operating position. System (inlet) pressure in pressure port 24 flows through passage 84 to the bore 74 to act on the surface of the piston 73, which displaces the disc 79 in the chamber 78 against the action of the coil spring 77. Fluid pressure downstream of the hydraulic jet motor is taken from the annular chamber 33 (FIG. 3) and 33' (FIG. 7) through passage 82 to the inlet port 81 in the sleeve 69. Fluid flows through the annular chambers 89 in the compensating spool 71 and the diametrically opposed ports in the sleeve to the outlet port 83. Displacement of the piston 73 is transmitted to the spool 71 through the aluminum rod 72 and results in the edges of the annular chamber 89 intersecting the edges of ports 80, thus providing variable area orifices which regulate the pressure of fluid flowing to the jet nozzle 110.

The spring rate of the coil spring 77 determines the degree of opening of the variable area orifices with respect to fluctuations in inlet pressure acting on the piston 73, so that a constant pressure is maintained at the jet nozzle 110.

Fluid leakage from around the spool 71 fills the chamber 78, which is connected to outlet chamber 39 (FIG. 1), and surrounds the aluminium rod 72. The fluid flows through the orifices 85 and the orifices 87 to fill the chamber 88 on either side of the flange 86, thus providing a dashpot type fluid damping arrangement which may be desirable in certain applications.

For the purpose of description itis assumed that the pressure and temperature compensating arrangement is shown in a neutral position in FIG. 12, with pressure and temperature within design limits which, taking the examples previously given, means that the system (inlet) pressure in bore 74 is 3,000 p.s.i., the pressure in inlet port 81 is 2,600 p.s.i., this being reduced by the restriction formed by the chambers 89 on the spool and the ports 80 in the sleeve to a pressure of 200 p.s.i. in the outlet port 83. A fall in system pressure in bore 74 causes the piston 73 to be moved downwards in the bore 74 under the action of the coil spring 77. This downward movement is transmitted to the spool 71 through the aluminium rod 72 to uncover more of the area of the ports in the sleeve 69, thereby increasing the area of the variable orifices formed with the chambers 89 on the spool, thereby maintaining a constant fluid pressure in the outlet port 83 regardless of the fall in fluid pressure in inlet port 81 caused by the fall in system (inlet) pressure.

The number of stages of reduction in the compensated reducer is such that when the spool 71 is in the neutral position the effective area of each orifice is greater than that of the jet pipe 95, so that the valves ability to operate in contaminated fluid is not impaired. The reliability aspect is, of course, improved in the arrangement described when the system (inlet) pressure falls. The opposite effect on this aspect due to a rise in system pressure need not be considered, as all sound systems are fitted with a pressure relief valve.

A fall in the temperature of the fluid surrounding the aluminium rod 72 causes contraction of the rod which is secured at its lower end to the piston 73 and at its upper end to the spool 71. As the piston 73 is balanced by the fluid pressure in the bore 74 and the coil spring 77, contraction of the rod 72 causes downward movement of the spool 71 within the sleeve 69 to again in crease the area of the orifices formed between the ports 80 and the chambers 89, causing an increase in pressure in outlet port 83 to compensate for pressure losses in the jet pipe arrangement, due to the increased viscosity of the lower temperature fluid.

From the outlet port 83 the fluid passes down the bore 90 of housing 91 into the deflecting jet 95 to eject from the jet nozzle 110 onto a splitter disc, as previously described in relation to the valve shown in FIG. 1. However, by passing the fluid through the unit as shown in FIG. 12, the upper static transfer jet 109 shown in FIG. 1 can be dispensed with, thus reducing fluid leakage. Displacement of the spool in a valve incorporating this modification is accomplished in exactly the same manner as that previously described by swinging the deflecting jet 95 through rotation of torque tube 96 by a torque motor (not shown).

If the valve is to be operated in an environment subject to acceleration forces, especially if the acceleration forces act along the longitudinal axis of the spool, it will be desirable to provide some means of compensating for these forces so that the spool position remains sensibly unaltered and the output load is unaffected. One means of achieving this is shown in FIG. 13.

Acceleration in the direction of arrow M results in an acceleration force on the spool 11 in the direction of arrow N, and is a product of the magnitude of acceleration and the spool mass. This force is balanced by a force in the direction of arrow P being a product of actuating chamber differential pressure (Ap) and the area (A) of the end of the spool upon which the pressure acts. The differential pressure (Ap) is created by a jet pipe displacement of L sin a where L is the length from the pivot point 107 to the nozzle of the jet pipe and a is the angular deflection of the jet pipe due to acceleration. The relationship between chamber differential pressure and jet pipe displacement is shown in the graph of FIG. 14. The angular deflection a is determined by the magnitude of acceleration in the direction 'of arrow M acting through the centre of gravity 108 which is located above the pivot point 107, and results in movement of the centre of gravity 108 in the direction of arrow to swing thedeflecting jet 95 about the pivot point 107. Relating this movement now to the valve of FIG. 1, more fluid will enter receiving chamber 42 than receiving chamber 41, causing an increase in fluid pressure inactuating chamber 48, resulting in a force equivalent to up A acting on the spool in the direction of arrow P (FIG. 13) to balance the acceleration force in the direction of arrow N, thereby compensating for acceleration forces and maintaining the spool in the desired position.

If desired, a damping facility can be provided on movement of the deflecting jet 95 by closing the gaps between the surfaces of the projection 99 and the walls of the body 17 and the retainer 93 to provide the necessary degree of viscous shear face.

FIG. shows a modified form of spool which will enable the valve of the present invention to be used as a vibration control valve. In this application the jet nozzle is fixed, there being no need, therefore, for atorque tube or torque motor. A required programme of vibration is shaped on the

edges

102 and 103 of two receiving

chambers

104 and 105 located one at each side of a splitter disc 101. As the spool 106 is rotated, by either of the fluid jet motor arrangements previously described, it will be forced to oscillate axially in order to maintain a state of pressure balance between the stationary jet pipe 100 and the actuating chamber pressures at either end of the spool. These oscillations result in fluid pressure being supplied alternately to ports 18 and 19 from inlet port 24 (FIG. 1) and are reproduced, within the response capacity of the system under vibration, at the load.

Dependent upon the extent of the operating temperature range and within the space limitations of the valve, the simple aluminum rod 72 shown in FIG. 12 could be replaced by a compound bi-metal concentric tube element, so increasing the valve opening per unit change of temperature.

In certain applications where a large fluctuating exhaust line back pressure is unavoidable the jet pipe pressure could be maintained, within certain limits, at a constant level abovethe back pressure by interposing a chamber'between the disc 79 and the piston 73 of appropriate area difference for the application, the chamber being connected to the outlet port 83 to be pressurized at jet pipe pressure.

In the embodiments of the invention hereinbefore described and illustrated it will be seen that a fluid control valve is provided in which a proportion of waste first stage fluid input pressure is harnessed to induce continuous rotation of the spool and to supply power to a servo-mechanism controlling displacement of the spool in the bore of the valve. The spool is rotated all the time that fluid pressure is supplied to the pressure port 24, regardless of whether the spool is positioned to permit a flow through the valve or whether the spool is positioned so as to shut off the flow. This continuous rotation prevents sticking and sluggish operation of the spool due to the fluid contamination, and also the onset of hydraulic lock, and means therefore that the valve is capableof efficient operation in areas which have hitherto caused many problems in hydraulic systems, particularly in the null position.

An important feature of the invention lies in the fact that no additional power source is required to either continuously rotate the spool or to cause displacement of the spool.

Many applications exist for valves with this facility wherever sensitive control is required in areas of relatively high fluid contamination and may, for instance, form the first stage of a hydraulic amplifier.

The modification shown in FIG. 15 indicates another unique example of the advantages to be gained in a particular application using a servo controlled spinning spool.

Another very important feature of a fluid control valve manufactured in accordance with the invention is the ease and simplicity with which fault-finding and maintenance can be achieved. For instance, by manufacturing the caps 50 from a transparent material, a visual check will determine whether a fault in a hydraulic system is being caused by a malfunctioning valve. If the spool is stationary, removal of a cap 50 will enable the spool to be withdrawn from the sleeve 49 for cleaning of the passages and especially the orifices 27 (FIG. 1) or 27 (FIG. 6). The spool is then replaced in the sleeve and the cap 50 refitted. The self-centering facility provided by the jet nozzle and splitter disc arrangement means that no set-up procedures are necessary, and that the valve is ready for immediate use.

The main difference between the valves of FIGS. 1 and 6 is that in FIG. 6 the splitter disc 40 has been moved to a central position on the spool as opposed to being located at one end, as shown in the valve of FIG. 1. The central position of the splitter disc shown in FIG. 6 is preferred from a manufacturing viewpoint, and also because of the fact that the dyanmic response of the valve is improved. From FIG. 6 it will be clear that the spool is made up of three parts, this type of construction being suitable also for the spool of FIG. 1.

Although several variations of the invention have been described and illustrated it is to be understood that various modifications can be made within the scope of the appended claims. For instance, in the valve of FIG. 1 the orifices 27 may be machined one from each side of the head 14. The fluid jet motor may be in the form of vanes on the spool onto which fluid is ejected to impart the necessary torque. The inner walls of receiving

chambers

41 and 42 may be vaned or otherwise formed to provide additional torque to the spool. Depending upon the levels of fluid contamination it may be possible in a particular installation to dispense with either one of the torque producing means previously described, though in the case of the splitter disc arrangement this may mean the provision of alternative forces for displacing the spool in the bore of the sleeve.

I claim as my invention:

1. In a fluid control valve, the combination comprising a valve body having a bore therein closed at each end and fluid inlet and outlet ports communicating with the bore, a spool located in the bore, said spool having annular chambers formed between a plurality of heads arranged so that the axial position of the spool controls the flow of fluid through the valve, a chamber in the bore at each end of the spool, a fluid jet motor formed in one of the heads on the spool for continuously rotating the spool when pressurized fluid is supplied to the inlet port comprising a plurality of orifices extending into the one head from an end adjacent a fluid inlet chamber on the spool and defined in part by the one head, the orifices connecting with at least one chamber formed on the circumference of the one head, ajet pipe assembly including a deflecting jet terminating in a longitudinally movable jet nozzle, the jet nozzle being in fluid communication with two annular receiving chambers formed in a head on the spool and separated by a splitter disc, and passage means within the spool connecting each of the annular receiving chambers with a different one of the chambers at each end of the spool.

2. The combination set forth in claim 1, wherein the fluid jet motor and the annular receiving chambers are located in the same head on the spool.

3. The combination set forth in claim 1, wherein the jet pipe assembly includes a static transfer jet.

4. The combination set forth in claim 1, wherein the jet pipe assembly is supplied with pressurized fluid from downstream of the fluid jet motor.

5. The combination set forth in claim 4, wherein a pressure reducer is installed between the fluid jet motor and the jet pipe assembly.

6. The combination set forth in claim 5, wherein the pressure reducer comprises a frustoconical unit having a plurality of chambers formed around its circumference, an orifice connecting the upstream end of the unit to an inlet chamber being one of the plurality of chambers, an orifice in walls between the chambers with the exception of the wall between the inlet chamber and an adjacent outlet chamber being also one of the pulurality of chambers, and an orifice connecting the outlet chamber to the downstream end of the unit.

7. The combination set forth in claim 1, wherein the chamber at each end of the spool is bounded in part by a transparent cap.

8. A fluid control valve having a body, a sleeve fixedly secured in the body and a spool located in a bore in the sleeve, a chamber in the sleeve at each end of the spool, inlet and outlet ports in the body communicating with ports in the sleeve, annular chambers formed between a plurality of heads on the spool, the heads being arranged so that the axial position of the spool controls the flow of'fluid through the valve, a fluid jet motor formed in one of the heads on the spool for continuously rotating the spool when pressurized fluid is supplied to the inlet port, and means for varying the fluid pressure being supplied to the chamber at each end of the spool, said fluid jet motor comprising a plurality of orifices extending intothe one head from the end adjacent a fluid inlet chamber on the spool, and defined in part by the one head, the orifices connecting with at least one chamber formed on the circumference of the one head.

Claims

1. In a fluid control valve, the combination comprising a valve body having a bore therein closed at each end and fluid inlet and outlet ports communicating with the bore, a spool located in the bore, said spool having annular chambers formed between a plurality of heads arranged so that the axial position of the spool controls the flow of fluid through the valve, a chamber in the bore at each end of the spool, a fluid jet motor formed in one of the heads on the spool for continuously rotating the spool when pressurized fluid is supplied to the inlet port comprising a plurality of orifices extending into the one head from an end adjacent a fluid inlet chamber on the spool and defined in part by the one head, the orifices connecting with at least one chamber formed on the circumference of the one head, a jet pipe assembly including a deflecting jet terminating in a longitudinally movable jet nozzle, the jet nozzle being in fluid communication with two annular receiving chambers formed in a head on the spool and separated by a splitter disc, and passage means within the spool connecting each of the annular receiving chambers With a different one of the chambers at each end of the spool.

8. A fluid control valve having a body, a sleeve fixedly secured in the body and a spool located in a bore in the sleeve, a chamber in the sleeve at each end of the spool, inlet and outlet ports in the body communicating with ports in the sleeve, annular chambers formed between a plurality of heads on the spool, the heads being arranged so that the axial position of the spool controls the flow of fluid through the valve, a fluid jet motor formed in one of the heads on the spool for continuously rotating the spool when pressurized fluid is supplied to the inlet port, and means for varying the fluid pressure being supplied to the chamber at each end of the spool, said fluid jet motor comprising a plurality of orifices extending into the one head from the end adjacent a fluid inlet chamber on the spool, and defined in part by the one head, the orifices connecting with at least one chamber formed on the circumference of the one head.