US3643700A

US3643700A - Valve

Info

Publication number: US3643700A
Authority: US
Inventors: Delbert L Black
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-08-24
Filing date: 1970-08-24
Publication date: 1972-02-22
Anticipated expiration: 1989-02-22

Abstract

A hydraulic system for independently controlling a plurality of individual reversible variable speed hydraulic motors from a common pressure supply source. A plurality of control valves, one for each motor to be controlled, are connected in a closed series circuit with a pump which is operable to recirculate fluid under pressure through the circuit. Each valve, when located in a centered or neutral position, permits all fluid entering the valve inlet to pass directly to the valve outlet. Upon displacement from the neutral position, a portion of the flow into the valve inlet is diverted to the associated motor, passes through the motor and is returned to the valve to rejoin the nondiverted portion of the flow. The magnitude and direction of flow through the motor is dependent upon the magnitude and direction of displacement of the valve from its neutral position. Displacement of a valve in either direction beyond a selected maximum displacement blocks the inlet port of the valve and the resultant increase of pressure at the pump triggers a pressure responsive switch to shut down the pump.

Description

United States Patent Black Feb. 22, 1972 [54] VALVE [72] Inventor: Delbert L. Black, Route 1, Box 92,

Wellington. Colo. 80549 [22] Filed: Aug. 24, 1970 [21] Appl. No.: 66,360

Primary Examiner-Henry T. Klinksiek ArromeyDrake, Crandell & Batchelder [57] ABSTRACT A hydraulic system for independently controlling a plurality of individual reversible variable speed hydraulic motors from a common pressure supply source. A plurality of control valves, one for each motor to be controlled, are connected in a closed series circuit with a pump which is operable to recirculate fluid under pressure through the circuit. Each valve, when located in a centered or neutral position, permits all fluid entering the valve inlet to pass directly to the valve outlet. Upon displacement from the neutral position, a portion of the flow into the valve inlet is diverted to the associated motor, passes through the motor and is returned to the valve to rejoin the nondiverted portion of the How. The magnitude and direction of flow through the motor is dependent upon the magnitude and direction of displacement of the valve from its neutral position. Displacement of a valve in either direction beyond a selected maximum displacement blocks the inlet port of the valve and the resultant increase of pressure at the pump trig gers a pressure responsive switch to shut down the pump.

4 Claims, 8 Drawing Figures PATENTEDFEBZZ m2 3.643. 700

SHEET 1 OF 6 INVENTOR DELBERT L. BLACK PATENTEDFEB22 I972 3.643. 700

swan 2 OF 6 INVENTOR DELBERT L. BLACK PATENTEDFEBEZ I872 3. 643.700

SHEET 3 OF 6 INVENTOR DELBERT L. BLACK PATENTEUFEB22 m2 SHEET 4 BF 6 INVENTOR DELBERT L. BLACK PAIENTEBFEB 22 I972 SHEU 5 [1F 6 INVENTOR DELBERT L. BLACK PAIENTEUFEB22 I972 3.643 700 SHEET 8 UF 6 INVENTOR DELBERT L. BLACK VALVE BACKGROUND OF THE INVENTION Although it has applicability in many other environments, the system of the present invention was designed for use in self-propelled irrigation systems of the type wherein a radially extending string of water distribution pipe is driven in movement about a central point to irrigate a circular area of land. Sprinkler systems of this type are commonly employed in the more arid regions of the great plains. The pipe strings are of substantial length in many instances, nonnally several hundred feet or more, and are supported and driven by towers or carriages located at spaced points along the string. Each tower is provided with an individual drive motor, and the problem is to coordinate the control of the various individual motors so that the entire string is maintained in accurate radial alignment from the central pivot point. This is an exceedingly difficult task, complicated by the fact that at any given moment some towers may be going up hill or passing through a muddy section while other towers are on a downgrade or passing over firmly compacted soil.

In most systems of this type, two sections of the pipe string are joined to each other at a tower by a flexible coupling which accommodates pivoting movement of the two sections relative to each other. Typically, a valve housing mounted on one of the two sections near the joint is actuated by a control element or linkage based on the other of the two sections so that relative pivotal movements of the two sections will shift the valve actuator.

Many of the presently used systems of this type employ the sprinkler system water as the fluid pressure source. In practice, this has usually turned out to be unsatisfactory for several reasons such as variation in pressure or lack of sufficient pressure. Further, many systems which employ water pressure as the power source are known as open circuit systems--i.e., water used for motive power of the tower is discharged directly on the ground from the driving mechanism.

SUMMARY OF THE INVENTION The present system employs a closed hydraulic system in which a high-pressure pump and a plurality of control valves are connected in a closed series circuit. Each valve is connected by a pair of control conduits to a reversible variable speed hydraulic motor which functions as the power drive unit. Each valve has a spool which is constructed, when in a neutral or centered position, to block both of the control conduits. The valve sleeve also has a pair of ports which provide direct communication between the valve inlet and valve outlet when the valve is in its centered position, at which time all fluid entering the valve inlet passes directly to the valve outlet. The valve housing is mounted upon one pipe section adjacent a joint; a lever mounted on the adjacent pipe section is employed to position the valve actuator in accordance with the angular position of the two pipe sections relative to each other. Displacement of the valve spool from its neutral or centered position partially closes the sleeve port at the valve outlet, and at the same time, connects one of the control ports to the inlet port while simultaneously connecting the other control port to the valve outlet, thus diverting a portion of the incoming fluid flow to pass through the hydraulic motor, from which it is returned to the valve and passed to the valve outlet. The magnitude and direction of the flow through the motor is dependent upon the magnitude and direction of displacement of the valve spool from its neutral position. The capacity of the pump is selected to be relatively high as compared to the operating characteristics of the individual power drive motors. Preferably, the motors will operate at full speed in either direction with a pressure drop of the order of S p.s.i. across the motor, the pump operating pressure being approximately L250 p.s.i.

A safety shutoff feature is provided to protect against jackkniling or breaking of the pipe string by shutting off the pump in the event a selected maximum angular displacement between two adjacent pipe sections is reached. This situation normally arises when one tower becomes bogged down or loses its traction. The safety shutdown is achieved by constructing the valve spool in a manner such that when the valve spool is displaced by a given maximum distance from its center position, the valve inlet port becomes blocked, thus increasing the pressure at the pump outlet port. A pressure responsive switch responds to this increase in pressure to shut down the pump drive, thus stopping all movement of the string.

Other objects, features and advantages of the invention will become apparent by reference to the following specification and to the drawings.

IN THE DRAWINGS FIG. 1 is a side elevational view of a typical self-propelled irrigation system;

FIG. 2 is a schematic diagram of a hydraulic system embodying the present invention;

FIG. 3 is a schematic top plan view of a tower and section joint of the system of FIG. I;

FIG. 4 is a cross-sectional view of a valve employed in the hydraulic system of FIG. 2 showing the valve in its neutral or centered position;

FIG. 5 is a cross-sectional view of the valve of FIG. 4, showing the valve spool displaced by a slight amount in one direction from its neutral position;

FIG. 6 is a cross-sectional view of the valve of FIG. 4 showing the valve displaced in the opposite direction, and by a greater amount, as compared to FIG. 5',

FIG. 7 is a cross-sectional view of the valve showing the valve spool and maximum displacement in one direction; and

FIG. 8 is a cross-sectional view of the valve showing the valve spool at maximum displacement in the opposite direction from FIG. 7.

Referring first to FIG. 1, there is shown in side elevational view, in more or less diagrammatic form, a self-propelled irrigation system of the type discussed above. Systems of this type are well known-see for example, Patent Office class 239. subclass I77. Typically, such systems include a central frame assembly designated generally I0. usually constructed at the well head of an artesian well or some other source of water, not shown. A rotating union I2 is employed to conduct water from the well or other source to a distribution system made up of a series of pipe section 14 interconnected in series with each other by flexible joints or couplings I6. pipe sections I4 extend radially from the rotary union I2, water being pumped through the connected pipe sections and disburse from the pipe by any of several forms of sprinkler means, not shown, suitably located along the pipe string. At spaced intervals along the pipe string, towers designated generally I8 support adjacent ends of adjacent pipe sections [4.

Each tower includes a suitable supporting frame work which is mounted upon a wheeled carriage 20, each carriage 20 having a drive means designated generally 22. The drive means are operated to drive the various towers along circular paths about the central pivot constituted by frame 10 while water is sprinkled from the distribution system which includes pipe sections I4, to irrigate the circular area traversed by the pipe string. The pipe string made up of pipe sections 14 typically is several hundred feet in length, and it is thus apparent that the circular path traversed by the outermost tower 18 may be many times longer than that traversed by one of the inner towers 18. Thus, each tower, in order to keep the string of pipes 14 in a straight line relationship to each other, must be driven at a speed dependent upon the radial distance between the tower and central frame I0, and the speed must be accurately regulated so that precise alignment of all of the towers 18 radially from central frame 10 is maintained. Further, because of a substantial length of the pipe string, the terrain being traversed at any given time can vary widely from tower to tower, and hence it is necessary to continually adjust and readjust the speed of the individual tower motors.

A hydraulic system for independently controlling the speed of a number of individual reversible variable speed hydraulic motors supplied with pressure fluid from a common pressure source is shown in FIG. 2. The system includes a supply pump schematically illustrated at 24 whose high-pressure side or outlet is connected via a conduit 28 to the inlet port 30 of a control valve 32. The outlet port 34 of valve 32 is connected via conduit 36 to the inlet port 30' of a second similar valve 32', whose outlet port 34' is connected via another conduit 38 to the inlet port 30" of a third similar control valve 32". The outlet port 34" of valve 32" is connected via a conduit 40 to the intake port 41 of the pump 24. The pump 24 is thus operable to continuously recirculate fluid under pressure through the series connected

valves

32, 32, and 32" and thence back to the pump intake via conduit 40. For purposes of illustration, the circuit of FIG. 2 is shown with only three control valves, however, in practice the number of valves in the circuit will correspond to the number of individual motors to be controlled-in the case of the irrigation system of FIG. 1, each tower 18 will be supplied with a valve 32.

Valve 32 is constructed with a pair of

control ports

42, 44 which are respectively connected via

conduits

46 and 48 to the opposite sides of a reversible variable speed hydraulic motor 50 which, in the irrigation system of FIG. 1 would constitute the drive motor of drive means 22. Motors 50 are of well-known, conventional construction and operate to drive in either direction at a speed dependent upon the rate of flow of hydraulic fluid through the motor, the direction of drive being determined by the direction in which the fluid flows through the motor. Valves 32' and 32" are similarly connected to corresponding motors 50' and S".

The structure and operation of valve 32 is best seen in FIGS. 4 through 8 inclusive. Valve 32 is constructed with a main housing 54 having a central bore chamber 56 which extends longitudinally entirely through housing 54. End caps 58 and 60 close the opposite ends of bore 56 and are sealingly secured to the opposite ends of housing 54 as by bolts 62. A series of

annular lands

64, 66, 68, 70, and 72 in port 56 cooperate with a fixed tubular sleeve 74 to form a series ofinternal chambers within the housing at the exterior of sleeve 74. Inlet port 30 takes the form of a bore passing through housing 54 to communicate with an inlet chamber 76 located at the exterior of sleeve 74 between

lands

68 and 70. Inlet chamber 76 can communicate with the interior of sleeve 74 via a plurality of ports 78 through sleeve 74. Outlet port 34 of valve 32 likewise takes the form of a bore passing through housing 54 to communicate with an outlet chamber 80 located at the exterior of sleeve 74 between

lands

68 and 66. Again, a series of radial ports 82 through sleeve 74 place outlet chamber 80 in communication with the interior of sleeve 74. Outlet port 34 is also in constant communication with

end chambers

84 and 86 located at the opposite ends of bore 56 via

branch passages

88 and 90 respectively.

Chambers

84 and 86 are in constant communication with the interior of sleeve 74 via slots 92 extending axially inwardly from the opposite ends of sleeve 74.

Control ports

42 and 44 pass inwardly through housing 54 to communicate respectively with

chambers

94 and 96.

Ports

98 and 100 respectively pass through the wall of sleeve 74 to provide a communicating passage between

chambers

94 and 96 and the interior of sleeve 74 when

ports

98 and 100 are unblocked.

A valve actuator designated generally 102 is slidably received within fixed sleeve 74. Actuator 102 includes a central hollow tubular sleeve portion 104 having closure plugs 106 sealingly secured in each of its opposite ends. Guide stems 108 and 110 are fixedly secured to and project from plugs 106, guide stem 110 being slidably and sealingly mounted in end cap 58, with guide stem 108 being slidably and sealingly received within end cap 60. The projecting portion of stem 108 is formed with a threaded section 112 so that the stern may be connected to a valve actuator to axially shift valve member 102 within fixed sleeve 74.

Central sleeve portion 104 of member 102 is formed, near its left-hand end as viewed in FIG. 4, with a series of axially elongated slots 114 which are normally aligned with, and thus uncover ports 78. Relatively narrow slots 116 are formed near the central portion of sleeve 104 to be located in alignment with ports 82 in sleeve 74 when valve 102 is at or closely adjacent its neutral or centered position shown in FIG. 4. The

axial width of slots 116 slightly exceeds the diameter of ports 82. A third series of slots 118 is formed adjacent the righthand end of sleeve 104.

Axial movement of member 102 relative to valve housing 54 is limited by a pair of spaced

stop elements

120, 122 mounted on guide stem 108 to engage end cap 60 upon a selected axial displacement of the valve member 102 from the neutral or central position shown in FIG. 4.

When valve member 102 is in its centered or neutral position shown in FIG. 4, ports 98 in fixed sleeve 74 are blocked by the end portion 124 of central sleeve 104, while ports 100 are likewise blocked by the opposite end portion 126 of central sleeve 104. When in this position, fluid under pressure entering in the inlet port 30 passes from chamber 76 radially inwardly through ports 78 and slots 114 to the interior of central sleeve 104 and thence radially outwardly through ports 82, outlet chamber and outlet port 34. All of the fluid entering inlet port 30 follows the foregoing path, end

portions

124 and 126 of the central sleeve blocking communication between the sleeve interior and either of

control chambers

94 and 96. It will be noted that in this condition, the valve is hydraulically balanced, equal and oppositely directed pressures being exerted against the inner walls of end plugs 106 and likewise against the respective outer walls of plugs 106 which are maintained at the pressure existing at outlet port 34 via

branch passages

88, 90, and the outer end chambers via

chambers

84 and 86. When the valve is in its centered position, no fluid flow exists to or from either of

control ports

42 or 44 and hence motor 50 is inoperative.

In FIG. 5, valve actuator 102 is shown displaced by a small amount to the right from its center or neutral position. As in the previous case, fluid entering inlet port 30 is passed from inlet chamber 76 inwardly through ports 78 and slots 114 of central sleeve 104 to the interior of the sleeve. Although slot 116 of sleeve 104 has been displaced slightly to the right, outlet ports 82 are still uncovered by slot 116 to permit fluid to flow from the interior of sleeve 104 through slot 116, ports 80 and chamber 82 and to outlet port 34.

The slight rightward displacement of valve member 102 has shifted right-hand end portion 126 of inner sleeve 104 to the right to partially uncover ports 100, thus permitting a small amount of fluid to flow from inlet port 30 and the interior of sleeve 104 through ports into control chamber 96 and thence through control port 44, a conduit 40 and conduit 48 to motor 50.

The slight rightward displacement of valve member 102 also is caused in portion 124 of sleeve 104 to partially unblock ports 98 to place control chamber 94 in communication with the left-hand end chamber of port 56 and thus with chamber 84, branch passage 88 and outlet port 34. These latter connections permit fluid to flow from motor 50 via conduit 46, control port 42 to outlet port 34, thereby establishing an operating flow of fluid through motor 50 to cause motor 50 to drive in one direction at a speed proportional to the magnitude of fluid flow through the motor.

In FIG. 6, the valve is shown displaced to the left from its neutral position by a greater amount than the slight displace ment of FIG. 5. In FIG. 6, valve member 102 has been shifted to the left by an amount such that slot 116 in valve sleeve 104 has been moved completely out of alignment with ports 82 in fixed sleeve 74, thereby blocking all direct communication between inlet port 30 and outlet port 341 The

respective end portions

124 and 126 of sleeve 104 have been displaced from their centered position by a distance sufficient to completely uncover both of

ports

98 and 100, ports 98 now being completely and directly connected to inlet port 30 via ports 78 and slots 114. Thus, all of the fluid flowing into inlet port 30 passes through ports 98 into control chamber 94, and thus via control ports 42 and conduit 46 to motor 50. Fluid passing from motor 50 travels via conduit 48 to outlet port 44 and chamber 96, thence via the now completely open ports 100 into the right-hand end chamber and thence via branch con duit 90 to outlet port 34. In this condition of the valve, motor 50 is receiving the full flow from inlet port 30 and thus will be driving at maximum speed in the direction opposite to that in which it was driven by rightward displacement of the valve in FIG. 5.

From a comparison of FIGS. 4, 5, and 6 it is seen that movement of valve member 102 in either direction from its center or neutral position causes the

end sections

124 and 126 of sleeve 104 to gradually uncover

ports

98 and 100 to place the ports in communication with inlet port 30 or with the adjacent end chamber of port 56, dependent upon the direction of displacement of member 102. The degree of communication is directly dependent upon the amount of displacement of member 102 and a corresponding throttling of ports 82 occurs. This arrangement provides for an establishment ofa flow of fluid through the connected motor 50 of a direction and magnitude directly related to the direction and magnitude of displacement of mem her 102 from its neutral position.

Valve 32 is provided with a safety shutoff feature to cause a shut down of the system in the event the displacement of valve member 102 exceeds a selected maximum displacement in either direction from its centered or neutral position. Displacement of valve member 102 from its centered or neutral position will normally represent an error signal which will, upon displacement of the valve, cause motor 50 to drive tending to correct the error. In many instances, the application of an abnormally large error signal indicates the existence of an abnormal fault, malfunction or emergency. In the irrigation system described above, for example, a typical situation ofthis type is encountered when the driving wheels of one of the towers become bogged down or completely lose traction so that the tower is unable to move, regardless of the amount of power applied to its drive motor. Adjacent towers, at this time, may have full traction and continue to drive ahead, thus continuously increasing the angular misalignment at the joint on the stalled tower and driving the pipe string into a jackknifed condition. When this occurs, it is obviously desirable to immediately stop all of the power drive motors to prevent jackknifing of the pipe string.

In the disclosed valve, the axial length of slots 114 in sleeve 104 determine the amount of displacement of valve member 102 which can occur before shutdown of the system will take place. It will be noted from FIG. 4 that ports 78 which communicate with inlet port 30 are located midway axially of slots 114. If valve member 102 is displaced in either direction from the FIG. 4 position by a displacement greater than one-half the length of slots 114, it is believed apparent that ports 78 will be covered either by end section 124 in the case of displacement of member 102 to the right or by edge portion 128 of sleeve 104 upon displacement of member 102 to the left.

These conditions of maximum displacement are shown respectively in FIGS. 7 and 8. Referring to FIG. 7, valve member 102 is shown at its maximum rightward displacement, with stop member 120 seated against the outer side of end cap 60 and end section 124 of sleeve 104 blocking ports 78. With port 78 blocked by end section 124, fluid flowing into inlet port 30 can not proceed beyond inlet chamber 76 and thus continued operation of the pump which supplied fluid to inlet port 30 will cause a buildup of pressure. Referring to FIG. 2, in the event that any of the inlet ports 30 30', or 30", of FIG. 2 should become blocked, it is believed apparent that pressure will immediately build up in conduit 28 to the full pump output pressure. Pressure responsive switch 52, connected in conduit 28 is set to be triggered by such an increase in pressure and switch 52 is electrically connected to stop operation of pump 24 in the event of an increase in pressure occasioned by blockage of the inlet port 30 of any of the valves in the system.

In FIG. 8, it is seen that displacement of valve member 102 to the left beyond a selected maximum dis lacement position in section 12 of valve sleeve 104 to bloc ports 78 with the same end result as described immediately above.

While one embodiment of the invention has been described in detail, it will be apparent to those skilled in the art that the disclosed embodiment may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting, and the true scope of the invention is that defined in the following claims.

lclaim:

1. A control valve comprising a housing means defining an axially elongated cylindrical main chamber in said housing, inlet and outlet passage means intersecting said main chamber at positions spaced axially of said chamber, a valve member slidably mounted in said chamber and having a centrally located hollow annular sleeve slidingly engaged with the wall ofsaid main chamber, annular end portions at each end of said sleeve, plug means for closing the annular end portions of said sleeve to seal the interior of said sleeve from the opposite end portions of said chamber, first means defining an outlet opening through said sleeve of an axial width substantially equal to the axial width of said outlet passage means at its intersection with said main chamber, said outlet opening and outlet passage means being in communicating registry with each other when said valve member is located in a neutral position relative to said main chamber, second means defining an inlet opening through said sleeve adjacent one end portion thereof of an axial width substantially greater than the axial width of said inlet passage means at its intersection with said main chamber, said inlet opening and said inlet passage being in communicating registry with each other when said valve member is at or within a predetermined range of displacement in either direction from said neutral position, third means defining a control opening in said sleeve adjacent the other end portion thereof, a pair of control passage means intersecting said main chamber at respective locations in registry with said end portions of said sleeve to be blocked thereby when said valve member is at said neutral position, and branch passage means connecting the opposite ends of said main chamber to said outlet passage means.

2. A valve as defined in claim 1 wherein said inlet opening extends axially from said one of said end portions for a distance approximately twice the distance between said inlet passage means and the control passage means blocked by said one of said end portions when said valve member is in said neutral position.

3. A valve as defined in claim 2 wherein said sleeve is formed with a pair of annular end portions of an axial width corresponding to the axial width of said control passage means at their intersection with said main passage whereby upon displacement of said valve member from its neutral position, one ofsaid control passage means is placed in communication with the interior of said sleeve while the other of said control passage means is placed in communication with the adjacent end of said main chamber.

4. A valve as defined in claim 1 wherein said housing is formed with a central passage therethrough having alternating annular lands and grooves therein, a fixed hollow sleeve sealingly engaged with said lands to isolate said grooves from each other, said inlet, outlet and control passage means comprising openings through the wall of said fixed sleeve and the interior of said fixed sleeve constituting said main chamber.

Claims

1. A control valve comprising a housing means defining an axially elongated cylindrical main chamber in said housing, inlet and outlet passage means intersecting said main chamber at positions spaced axially of said chamber, a valve member slidably mounted in said chamber and having a centrally located hollow annular sleeve slidingly engaged with the wall of said main chamber, annular end portions at each end of said sleeve, plug means for closing the annular end portions of said sleeve to seal the interior of said sleeve from the opposite end portions of said chamber, first means defining an outlet opening through said sleeve of an axial width substantially equal to the axial width of said outlet passage means at its intersection with said main chamber, said outlet opening and outlet passage means being in communicating registry with each other when said valve member is located in a neutral position reLative to said main chamber, second means defining an inlet opening through said sleeve adjacent one end portion thereof of an axial width substantially greater than the axial width of said inlet passage means at its intersection with said main chamber, said inlet opening and said inlet passage being in communicating registry with each other when said valve member is at or within a predetermined range of displacement in either direction from said neutral position, third means defining a control opening in said sleeve adjacent the other end portion thereof, a pair of control passage means intersecting said main chamber at respective locations in registry with said end portions of said sleeve to be blocked thereby when said valve member is at said neutral position, and branch passage means connecting the opposite ends of said main chamber to said outlet passage means.

3. A valve as defined in claim 2 wherein said sleeve is formed with a pair of annular end portions of an axial width corresponding to the axial width of said control passage means at their intersection with said main passage whereby upon displacement of said valve member from its neutral position, one of said control passage means is placed in communication with the interior of said sleeve while the other of said control passage means is placed in communication with the adjacent end of said main chamber.