Abstract:
A bi-directional metering valve assembly is provided to selectively direct hydraulic fluid under high pressure to a load. The assembly includes a valve block defining a first port that receives hydraulic fluid from a source, and a second port that directs hydraulic fluid toward a load. A rotatable valve member defines first and second apertures in an axial face that may be placed in selective communication with the first and second ports, respectively, to direct hydraulic fluid from the source to the load. At least one metering sealing assembly provides an interface between the valve block and the valve member. The metering sealing assembly includes a gasket that surrounds one of the first and second ports and defines a flange that is sized to completely overlap and seal the corresponding aperture. The valve member is operable to control the direction of fluid flow, and make fine adjustments to the hydraulic fluid flow rate.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS NOT APPLICABLE 
   This claims the benefit of U.S. Provisional Patent Application No. 60/475,287 filed Jun. 3, 2003, the disclosure of which is incorporated by reference as if set forth in its entirety herein. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
   NOT APPLICABLE 
   FIELD OF THE INVENTION 
   The present invention relates to control valve assemblies, and in particular to a control valve that controls whether the hydraulic fluid flow is on or off and the rate and direction of fluid flow. 
   BACKGROUND OF THE INVENTION 
   Fluid flow control valve assemblies are commonly used for controlling the flow of a pressurized fluid, such as a hydraulic and pneumatic fluid and the like, into and out of cylinders to extend and retract a load. Conventional control valve assemblies typically include one or more intake ports that can be selectively connected between the fluid source and the load, and a fluid exhaust port that enables fluid to flow from the load into a return tank. Such valves are typically multi-positional to selectively engage one or more ports depending on the desired direction of fluid flow. 
   One such known fluid flow control valve assembly for operating a high pressure single acting hydraulic cylinder is disclosed in U.S. Pat. No. 4,471,805, the disclosure of which is incorporated by reference as if set forth in its entirety herein for the purposes of general valve assembly operation well known in the art. The ′805 patent discloses a first valve body having a pressure port, an outlet port to a load, and a tank port that can be engaged to select the direction of hydraulic fluid flow. A control handle actuates a second valve body having four control ports to select one of several possible modes of operation (i.e., rapid advance, slow metered advance, hold, and return) to control the hydraulic flow rate. 
   Conventional high-pressure systems thus require two separate valve assemblies to control the motion of a cylinder, thereby increasing the complexity of the device and necessitating excess cost and resources during fabrication. A further limitation is that the design is unidirectional in that the hydraulic fluid flow rate is only controlled in one direction of fluid flow. Furthermore, construction and operation of such conventional devices is unnecessarily complex and tedious. 
   It would therefore be desirable to provide a single high-pressure control valve having bi-directional control of the direction of hydraulic fluid flow while also metering the rate of pressurized fluid flow through the valve. 
   BRIEF SUMMARY OF THE INVENTION 
   In one aspect, a metering valve assembly is provided that selectively directs hydraulic fluid under high pressure to a load. The valve assembly includes a valve block defining a first port that receives hydraulic fluid from a source, and a second port that directs hydraulic fluid to the load. A rotatable valve member is provided having an axially facing surface in which first and second apertures are formed that are in fluid communication with each other, and that can be placed in selective communication with the first and second ports, respectively, to direct hydraulic fluid from the source to the load. At least one metering sealing assembly provides an interface between the valve block and the axially facing surface of the valve member. The metering sealing assembly includes a gasket defining a flow path therethrough. The gasket surrounds one of the first and second ports and defines a flange that abuts the axially facing surface of the valve member and is sized to completely overlap and seal the corresponding aperture in at least one position of the valve member, and to provide continuously increasing communication between the flow path through the gasket and the corresponding aperture as the valve member is rotated toward a position in which maximum communication is provided between the flow path and the aperture. 
   These and other aspects of the invention are not intended to define the scope of the invention for which purpose claims are provided. In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration and not limitation a preferred embodiment of the invention. Such embodiment does not define the scope of the invention and reference must therefore be made to the claims for this purpose. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals correspond to like elements throughout, and in which: 
       FIG. 1  is a perspective view of a control valve schematically coupled to a controlled load in accordance with a preferred embodiment of the invention; 
       FIG. 2  is a sectional side elevation view of the control valve illustrated in  FIG. 1 ; 
       FIG. 3  is an exploded assembly view of a valve assembly portion of the control valve illustrated in  FIG. 2 ; 
       FIG. 4  is a perspective view of a portion of the control valve illustrated in  FIGS. 1-3 , looking at the lower surface of the valve disc, with the valve in a metered flow position; 
       FIG. 5   a  is a top plan view of a valve member taken along line  5   a - 5   a  illustrated in  FIG. 2  showing the valve member in a “no flow” position; 
       FIG. 5   b  is a detailed view of the valve member illustrated in  FIG. 5   a;    
       FIG. 6   a  is a view similar to  FIG. 5   a  but with the valve member in a metered flow position; 
       FIG. 6   b  is a detailed view of the valve member illustrated in  FIG. 6   a;    
       FIG. 7   a  is a view similar to  FIG. 5   a  but with the valve member in a “full flow” position; 
       FIG. 7   b  is a detailed view of the valve member illustrated in  FIG. 7   a;    
       FIG. 8   a  is a view similar to  FIG. 5   a  but with the valve member in a “return to reservoir” position; and 
       FIG. 8   b  is a detailed view of the valve member illustrated in  FIG. 8   a.    
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 and 2 , a rotary control valve  20  includes an elongated rectangular manifold housing  22  at its base. Manifold housing  22  presents opposing elongated front and rear walls  24  and  26 , respectively, opposing side walls  28  and  30 , respectively, and upper and lower walls  32  and  34 , respectively. A first opening  31  is formed in side wall  30  that is connected via a conduit  35  to a port  41  of an extendable load  33 , illustrated as a hydraulic cylinder. A second opening  39  is formed in side wall  30  that is connected to a hydraulic reservoir  37 . Fluid is thus supplied to port  41  via opening  31  to extend the load  33 , and fluid is returned from port  41  to valve  20  via opening  31  to retract it. The returned fluid then flows through the valve  20  into hydraulic reservoir  37  via opening  39 . 
   A pressure-compensated flow control block  36  is connected to manifold housing  22 , and includes a flow control spool  38  as described in U.S. Pat. No. 4,471,805. A rectangular valve housing  44  is mounted to the upper wall  32  of manifold housing  22 , and includes a lower valve block  46  connected at its upper end to a valve cap member  48  via a plurality of screws  50 . A rotatable handle  53  is connected to the upper end of valve cap  48 , and actuates a valve assembly  72  disposed in valve housing  44  for controlling and metering fluid flow through the control valve  20 . 
   Referring also to  FIG. 3 , the components of valve assembly  72  and handle  53  will now be described. Specifically, handle  53  includes a cylindrical disc member  52  that is rotatably mounted onto the upper surface of valve cap  48 . Disc member  52  defines a cylindrical bore  60  extending axially there through that receives the upper keyed end  62  of a coupling shaft  64  to rotatably couple the shaft with disc member  52 . A lever  54  extends into the radial outer wall of disc  52 , and is fastened to disc  52  via a set screw  56  and washer  57  to rotatably couple lever  54  to disc  52 . A knob  58  is disposed at the outer end of lever  54  that enables a user to easily rotate disc  52  during operation. 
   Disc  52  is coupled to valve cap  48  via a roll pin  66  along with a spring  68  and ball  70  that extend up from valve cap  48  and into disc  52  to facilitate rotation of disc  52  relative to valve housing  44 . In addition, roll pin  66  along with spring  68  and ball  70  limit the degree of rotation of disc  52 , and furthermore establish tactile feedback in order to positioning disc  52  in one of a plurality of distinct positions. 
   Valve assembly  72  controls the status (i.e. on/off) of high pressure hydraulic (or the like) fluid flow to and from load  33  along with the rate and direction of fluid flow. Control of the hydraulic fluid is achieved with a rotating cylindrical valve disc  74  disposed in valve housing  44 . Specifically, valve cap  48  includes a downwardly extending shoulder  89  that encapsulates disc  74  and is connected at its lower end to the upper end of valve block  46 . Valve cap  48  is fastened to valve block  46  via a plurality of screws  125  and one or more roll pins  127  that ensure proper alignment. 
   Disc  74  presents opposing lower and upper surfaces  71  and  75 , respectively, that are joined at their outer ends to an outer radial wall  113 . A central bore  76  extends vertically through the center of disc  74  in alignment with bore  60 , and receives the lower end  65  of coupling shaft  64 . An aperture  67  extends radially through the lower end  65  of shaft  64 , and a corresponding aperture  80  extends radially through disc  74  and aligned with aperture  67 . A key  78  inserted through apertures  80  and  67  rotatably locks the position of disc  74  relative to shaft  64  and handle  53 . Accordingly, rotation of handle  53  correspondingly rotates disc  74  during operation. 
   The upper surface  75  of disc  74  engages valve cap  48  via a sealing assembly  73  that facilitates rotation of disc  74  relative to valve cap  48 . Sealing assembly  73  includes an o-ring  90  disposed in a radial notch  81  formed in the radially inner edge of the lower surface of shoulder  89 . A bearing plate  88  is seated against valve cap  48 , and a needle bearing  86  is disposed between upper surface  75  of disc and bearing plate  88 . Bearing  86  thus facilitates rotation of disc  74  relative to valve block  48  by riding along upper surface  75  of disc  74  and the lower surface of bearing plate  88 , which is held stationary relative to valve cap  48 . An o-ring  82  and corresponding backup washer  84  are disposed in a groove  85  extending radially into shaft  64  at a location such that o-ring  82  seals shaft  64  with respect to valve cap  48 . 
   Valve block  46  defines a generally rectangular upper surface  91  having a centrally disposed bore  95  formed vertically therein that extends through valve block  46 . Bore  95  is aligned with bore  76  of disc  74  and partially receives the lower end  65  of shaft  64 . A counterbore  92  also extends into upper surface  91  to define a sunk radial flange  94  surrounding bore  95 . Counterbore  92  has a diameter sufficient such that flange  94  provides a seat for disc  74 . 
   A plurality of ports is formed in flange  94  that are coupled to a pressurized hydraulic fluid source  109 , load  33 , and reservoir  37 . Each port can be selectively coupled to source  109 , load  33 , and/or reservoir  37  by a user via handle  58  to rotate disc  74  and thereby control valve operation, and to turn on and off, and meter the flow rate through valve assembly  72 , as will now be described. 
   In particular, a first port  96  extends through flange  94  and is connected to load port  41  via a load return channel  102  that is, in turn, connected to a main channel  106 , both of which extend through manifold housing  22 . Port  96  is thus a load return port that enables hydraulic fluid to return from the load to the valve disc  74 , which can be configured to further direct the returned fluid to tank port  39 . 
   A second port  98  is a load supply port that extends through flange  94  at a location counterclockwise with respect to port  96 . Port  98  is coupled to channel  106 , and enables pressurized fluid to flow from valve housing  44  to port  31 . 
   A third port  100  is a hydraulic fluid supply port that extends through flange  94  at a position counterclockwise with respect to port  98 . Pressurized fluid source  109  supplies fluid to a connector  107  (See  FIG. 2 ) which is coupled to fluid supply port  100  via a channel (not shown) extending through manifold housing  22 . Pressurized hydraulic fluid is supplied from source  109  to port  31  when port  100  is connected to port  98  by appropriately positioning disc  74 . 
   Three o-rings  123  (one shown) engage the lower surface of valve block  46  to seal the lower ends of ports  96 ,  98 , and  100 . 
   A pair of drains  112  and  115  coupled to reservoir  37  are formed from a corresponding pair of grooves formed from U-shaped cutouts extending into valve block  46  from bore  95 , that extend vertically along the entire height of valve block  46 . Drain  112  is located between first port  96  and second port  98 , while drain  115  is located clockwise with respect to first port  96 . Both drains  112  and  115  are coupled to reservoir  47  via a vertical conduit  105  linked to a channel  104  extending through manifold housing  22 . Accordingly, fluid flowing into either drain  112  or  115  flows through conduit  105 , travels through channel  104 , and is delivered to reservoir  37 . 
   Advantageously, a check valve  108  is disposed in channel  106  that enables unidirectional fluid flow from load supply port  98  to port  31  while preventing backflow of hydraulic fluid from port  31  towards load supply port  98 . Channel  102  is connected to channel  106  at a position downstream of the check valve  108  (relative to the direction of fluid supplied to load  33  ). Accordingly, when load return port  96  (and thus channel  102  ) is closed, check valve  108  prevents backflow to hold the load  33  in an extended position when fluid flow to port  31  is discontinued. When it is desirable to retract load  33 , valve assembly  72  can be actuated to permit fluid to flow from port  41  into port  31  and channel  102 , bypassing check valve  108 , through drain  112  or  115 , and into hydraulic reservoir  37  via channel  104 . 
   Unless stated otherwise, the terms “clockwise” and “counterclockwise” are used throughout this disclosure with reference to a top plan view of the valve assembly  72  (as shown in  FIGS. 5-8 ) along the directions identified by Arrows C and C′, respectively ( FIG. 3 ). 
   Referring now to  FIGS. 3 and 4 , fluid flow is directed between the various ports  96 ,  98 , and  100 , and drains  112  and  115 , via rotating valve disc  74 . Specifically, first and second apertures  114  and  116 , respectively, are formed vertically into the undersurface  71  of disc  74  and terminate before extending through to the upper surface  75 . The terminal ends (not shown) of apertures  114  and  116  are connected via a nested channel  118  (see also  FIGS. 5-8 ) that extends from circumferential wall  113  at a location proximal aperture  116 , through apertures  116  and  114 , and terminates at a location downstream of aperture  114  without extending entirely through disc  74 . Channel  118  is sealed via a plug  120  disposed at circumferential wall  113 , and places apertures  114  and  116  in fluid communication. 
   Apertures  114  and  116  can thus be selectively coupled in tandem to certain ones of ports  96 ,  98 ,  100 ,  112  , and  115  in order to direct the hydraulic fluid flow as desired. For instance, when ports  98  and  100  are coupled via apertures  114  and  116 , hydraulic fluid will flow from source  109  through port  100 , and subsequently through channel  118 , which links ports  100  and  98 . The pressurized fluid will then flow through port  98  and to port  31  to extend load  33 . If port  96  is coupled to either drain  112  or  115 , hydraulic fluid will flow from port  31 , through port  96  and channel  118 , where it will then flow into whichever drain  112  or  115  is coupled to port  96 , thereby retracting the load  33 . 
   With continuing reference to  FIGS. 3 and 4 , it is appreciated that disc  74  and valve housing  44  are preferably formed from a metal or other suitably strong material to withstand the high pressure associated with the hydraulic fluid, and that the ports  96 - 100  alone are therefore incapable of forming a seal with the metal undersurface  71  of disc  74 . Accordingly, ports  96 - 100  are sealed against the undersurface  71  of disc  74 . In particular, ports  98  and  100  interface with disc  74  via a metering assembly  110 , while port  96  interfaces with disc  74  via a non-metering sealing assembly  111 . 
     FIG. 3  illustrates an assembly view of metering assembly  110  being installed in conjunction with port  98 , while port  100  is illustrated with metering assembly  110  already installed. Metering assembly  110  includes a vertically extending coil spring  122  that is disposed at the lower end of the assembly. A sealing o-ring  124  is sandwiched between a pair of washers  126  in a groove formed around the outside of a gasket  128 . The gasket  128  is biased towards the undersurface of disc  74  under the force of spring  122  and also any hydraulic pressure urging it upwardly. Referring also to  FIG. 4 , gasket  128  includes a vertically extending annular body  93  defining a flow path  99  there through. A lower flange  130  seats against spring  122 , and an upper flange  132  forms a sliding seal against the lower surface  71  of disc  74 . 
   Upper flange  132  of metering gasket  128  has a radial width sufficient to completely cover and seal apertures  114  and  116  during operation when the apertures  114  and  116  are positioned over flange  132 . Gasket  128  can thus seal the undersurface of disc  74  or, alternatively, determine the degree of alignment between flow path  99  and apertures  114  and  116  to control the flow rate of hydraulic fluid through the corresponding port between completely closed and completely open positions. Gasket  128  is preferably made of a metal or other like material, with sufficient surface flatness and finish at the upper flange  132  suitable for forming a reliable high pressure hydraulic seal against lower surface  71  of disc  74  under the force of spring  122 , yet sill allowing sliding of disc  74  as it is rotated. 
   As described above, load return port  96  interfaces with the undersurface  71  of disc  74  via a non-metering sealing assembly  111 . Sealing assembly  111  includes spring  122 , o-ring  124 , and washers  126  as described above with respect to metering assembly  110 . A standard shear seal in the form of gasket  129  is disposed above the upper washer  126  and biased towards the undersurface  71  of disc  74  under the force of spring  122 . However, gasket  129  differs from metering gasket  128 , as the upper flange  131  of gasket  129  has a radial width less than the size of the openings  114  and  116 . Gasket  129  is thus incapable of completely covering apertures  114  and  116 , and thus can not meter the flow of fluid returning to reservoir  37  between completely closed and completely open positions. It should be appreciated, however, that load return port  96  could alternatively interface with disc  74  via a metering assembly  110 , if desired, in order to control the flow rate of hydraulic fluid from load port  41  and the corresponding rate of load retraction. 
     FIG. 4  illustrates the interface between port  98  and aperture  114 , it being appreciated that the interface between either port  96  and  98  and either aperture  114  and  116  is similarly metered. During operation, metering assembly  110  can prevent fluid from flowing through port  98  by rotating disc  74  to a position whereby flange  132  completely covers aperture  114 . Disc  74  can then be rotated via handle  53  in the direction of Arrow A in order to begin fluid flow through port  98 . In particular, as disc  74  is rotated, flow path  99  is brought into partial alignment with aperture  114 . As disc  74  is further rotated, a greater portion of aperture  114  is brought into fluid communication with flow path  99 , thus enabling a greater fluid flow rate through port  98 , until the entire aperture  114  is aligned with flow path  99  to enable fill fluid flow. 
   As illustrated, apertures  114  and  116  are diamond-shaped with respect to flange  132  as disc  74  is rotated in order to easily meter fluid flow at a desired rate. A diamond shape is preferable because the amount of overlap between apertures  114  and  116  and flow paths  99  can be finely controlled at low flow rates (i.e., positions near the fully closed position). It should be appreciated, however, that apertures  114  and  116  could alternatively assume any desired shape that enables the flow of fluid flowing through the disc  74  to be metered in accordance with the present invention. The term “geometric aperture” is thus intended to encompass shapes such as a diamond, square, rectangle, circle, triangle, quadrilateral, and other like shapes. Preferably, however, the front portions apertures  114  and  116  that initially engage flanges  32  taper to enable low flow rates to be easily metered. 
   The operation of valve assembly  72  will now be described in more detail with reference to  FIGS. 5-8 . 
   Referring initially to  FIGS. 5A-5B , valve assembly  72  is illustrated in a “hold”, or “no flow” position. In particular, handle  54  is rotated to correspondingly rotate disc  74  relative to valve block  46  until flange  132  of metering assembly  110  corresponding to port  100  completely overlaps aperture  116 . Accordingly, pressurized hydraulic fluid flowing from source  109  through port  100  towards disc  74  is sealed against the undersurface  71  of disc  74  via metering assembly  110  and prevented from entering channel  118 . Hydraulic fluid is thus prevented from traveling through aperture  114  to load port  41  via valve port  98 . 
   Ports  100  and  98  are spaced such that flange  132  corresponding to port  98  preferably completely covers aperture  114  when valve  20  is in a “no flow” configuration, so it is closed even through check valve  108  prevents backflow from port  31  to port  98 . Furthermore, flange  131  of sealing assembly  111  corresponding to load return port  96  is sealed against the undersurface  71  of disc  74  to prevent pressurized hydraulic fluid in an extended load cylinder from traveling through bypass channel  102  and into reservoir  37 . 
   Placing valve  20  in a “hold” orientation enables power to source  109  to be discontinued while maintaining an extended load  33  over a prolonged period of time, thereby reducing wear and tear on the supply pump and valve assembly  72 . It may also be desirable to rotate the valve assembly  20  to the “hold” orientation when load  33  is retracted and the hydraulic fluid source  109  is off in order to prevent fluid from immediately flowing to load  33  when power is subsequently supplied to the hydraulic fluid source  109 . In order to gradually introduce pressurized hydraulic fluid to load  33 , valve  20  may be positioned in a metering configuration, as will now be described. 
   Specifically, referring again to  FIG. 4  and also  FIGS. 6A-B , disc  74  is rotated slightly counterclockwise in the direction of Arrow A ( FIG. 6A ) such that a portion of apertures  114  and  116  are removed from being covered by flanges  132  and instead are partially aligned with the corresponding flow paths  99  linking ports  98  and  100 , respectively. Accordingly, a “metered flow” position is achieved whereby hydraulic fluid flows from source  109  between ports  100  and  98  via channel  118 , and subsequently flows through check valve  108  toward port  31  and into load port  41 . When a small portion of apertures  114  and  116  are aligned with ports  98  and  100 , respectively, a slow metered advance of hydraulic fluid occurs. As apertures  114  and  116  become increasingly aligned with ports  98  and  100 , hydraulic fluid flow to load  33  is correspondingly increased to initiate a rapid metered advance. 
   It should be appreciated that aperture  114  is preferably configured to be placed in fluid communication with port  98  slightly prior to aperture  116  being placed in fluid communication with port  100 . As a result, a conduit from channel  118  to load port  41  is opened prior to pressurized hydraulic fluid entering channel  118  to help equalize the pressure in channel  118  to the load pressure prior to opening channel  118  to the source pressure. In addition, since the metered aperture at  116  is smaller than that of  114 , more metering is occurring at port aperture  116  than at aperture  114 , for more precise control. Alternatively, as described above, flanges  114  and  116  could be configured to engage ports  98  and  100  simultaneously, or to do so with  116  engaging first. Since there are two metered apertures, the total pressure drop between the port  100  and the port  98  can be divided between the two apertures so that, especially for high pressures, the pressure drop does not occur all at one aperture. 
   Referring now to  FIGS. 7A and 7B , as disc  74  is further rotated counterclockwise, apertures  114  and  116  are brought into complete alignment with ports  98  and  100 , which are sized to completely overlap the corresponding apertures  114  and  116  to enable full fluid flow through conduit  118  to port  31 . 
   Markings  59  (See  FIG. 1 ) can also be provided on handle  53  or disc member  52  that may be read by a user to determine the flow rate of the metered hydraulic fluid, whether flow is completely turned off (hold) and whether the load is connected to tank  37 . For instance, if 50% of full fluid flow to load  33  is desired, the user would rotate handle  54  and disc member  52  to correspondingly place half of the surface area of aperture  116  in alignment with port  100 . Once the load  33  has reached its desired extension, the valve  20  may be actuated to the “no flow” position discussed above, and power to hydraulic fluid source  109  may be discontinued. When moving to the no flow (hold) position, aperture  116  is closed first, followed by the closing of aperture  114 . This assures that the pressure in channel  118  will be equalized to the load pressure in the hold position. 
   Although in the preferred embodiment, metering assemblies  110  are associated with both ports  100  and  98 , in some applications only one of the ports  100  or  98  may need to be metered in order to sufficiently meter the flow of hydraulic fluid to load port  31 . Specifically, if port  100  is metered, by way of the diamond shaped or other suitable geometric aperture in combination with metering assembly  110 , and port  98  has a non-metering sealing assembly  111  installed, the hydraulic fluid flow could be metered when entering channel  118 , and thus will also be metered when flowing to load  33  even if aperture  114  is filly open with respect to port  98 . Likewise, if port  100  is non-metering, and port  98  is metered, full hydraulic fluid flow would enter channel  118 , however the flow to load  33  would be metered because aperture  114  would be only partially aligned with port  98 . Of course, sufficient clearance would need to exist to ensure that aperture  116  and port  100  are fully aligned when the valve disc  74  is further rotated to place aperture  114  in full alignment with metered port  98 . 
   Referring now to  FIGS. 8A and 8B , disc  74  may be rotated to a “return” or “retract” position whereby fluid is drained from load  33  and returned to the reservoir  47  via channel  104 . In particular, aperture  114  is aligned with load return port  96  and aperture  116  is aligned with drain  112  (alternatively aperture  116  could be aligned with load return port  96  and aperture  114  could be aligned with drain  115  ). Accordingly, hydraulic fluid travels from load port  41  into manifold housing  22  via channel  106  and towards check valve  108 . The returning fluid bypasses the check valve  108  via channel  102  and travels into disc  74  via port  96  and aperture  114 . The hydraulic fluid then travels through channel  118  and exits disc  74  via aperture  116  and flows into groove  112  where it is directed to reservoir port  39  via channels  104  and  105 . 
   It should thus be appreciated that the valve  20  in accordance with the preferred embodiment enables a user to both select the direction of fluid flow and meter in a continuous manner the flow of hydraulic fluid to a load using a single valve assembly  72 . Valve  20  could also be modified to meter the flow of hydraulic fluid returning from port  31  to the reservoir  37  via channel  104 , if so desired, by replacing standard sealing assembly  111  with a metering assembly  110 . The invention is specifically adapted for high pressure hydraulic applications typically between 5000 and 10000 PSI. As used herein, high pressure refers to pressure greater than 5000 PSI. While the present system implements one fluid source and one load, it should be appreciated that any system implementing any number of fluid sources and loads may benefit from the present invention. 
   Furthermore, though the valve  20  described herein is configured for a single-acting cylinder, load  33  could alternatively be double-acting in accordance with the present invention. One skilled in the art would appreciate, for instance, that any number of apertures may be formed in disc  74  that may be connected by internal channels extending within disc to be selectively coupled to ports formed in valve block  46 . The ports may have metering assemblies as described above or normal sealing assemblies depending on the desired function of the port. 
   The invention has been described in connection with what are presently considered to be the most practical and preferred embodiments. However, the present invention has been presented by way of illustration and is not intended to be limited to the disclosed embodiments. Accordingly, those skilled in the art will realize that the invention is intended to encompass all modifications and alternative arrangements included within the spirit and scope of the invention, as set forth by the appended claims.