Patent Publication Number: US-2012042976-A1

Title: Fluid manifold

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 61/374,831, flied Aug. 18, 2010, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present invention relates to a fluid manifold. More specifically, this invention relates to a fluid manifold and a hydraulic accumulator. 
     BACKGROUND OF THE INVENTION 
     Fluid manifolds are well known and may act as connection devices for fluid components. For example, fluid manifolds may be used in fluid systems and may act to provide a connection device between and among fluid components of the fluid system. The fluid components that are connected by the manifold may for example include a component source of fluid energy and a component recipient of fluid energy or multiple such components. The component source of fluid energy may for example include a fluid pump or a fluid pressure storage device. The component recipient of fluid energy may for example include a fluid valve, a fluid motor, and/or another fluid pressure storage device. 
     Accumulators are also well known and act as storage devices for storing energy in the form of fluid under pressure. For example, hydraulic fluid accumulators may store hydraulic fluid under pressure for use by other fluid components. Since hydraulic fluid is non-compressible, hydraulic accumulators may include a pressurization source for acting upon the stored hydraulic fluid. Known pressurization sources for hydraulic accumulators include for example springs, a weight that is acted upon by gravity, or a charged gas (or gas under pressure) such as compressed air. Charged gas is the most commonly used pressurization source for hydraulic accumulators There are two main types of charged gas hydraulic accumulators; a bladder accumulator and a piston accumulator. In a bladder accumulator, the interior of the accumulator body or shell is divided by an expandable bladder or diaphragm into two chambers. Hydraulic fluid is received in and stored in one of the chambers, while the charged gas is received in and stored in the other chamber. In many bladder accumulators, the expandable bladder is shaped like a balloon with an opening to the interior of the bladder fixedly supported relative to one end of the accumulator body. In piston accumulators, a floating piston located within and sealing against the accumulator body defines a boundary between the two chambers of the accumulator. The charged gas acts upon one side of the floating piston to apply a force to the hydraulic fluid that is located on an opposite side of the floating piston. In both bladder and piston accumulators, aligning, connecting and disconnecting multiple fluid components or conduits to and from the accumulator when installing or exchanging or servicing the accumulator can, at times, be difficult and/or labor intensive, particularly when the accumulator is large and heavy and is fixed in place relative to another structure. 
     SUMMARY OF THE INVENTION 
     At least one embodiment of the invention provides a a fluid manifold and a fluid manifold in combination with a fluid component. The fluid component may be a charged gas chamber of a hydraulic accumulator. The manifold may include multiple fluid ports and a single point rotatable connection for connecting the manifold multiple ports to the accumulator. The fluid manifold may provide a connection for the charged gas source to the charged gas chamber and may be rotated through 360 degrees about a longitudinal axis of the accumulator. The rotatable gas manifold may simplify installation of the accumulator by enabling its associated fluid components and/or conduits to be easily aligned with, connected to and disconnected from the accumulator. Thus, when large accumulators are installed in a system, the accumulators may be fixed in place relative to their support structure without the need to align or realign the other fluid components and/or conduits associated with the charged gas side of the accumulator. 
     The invention further provides a fluid manifold for use with a fluid component that includes a fluid component fluid port. The fluid manifold may include a body and a locking connector. The body may have a plurality of manifold individual fluid ports and a manifold common fluid port. Passages in the body may establish fluid communication between the manifold individual fluid ports and the manifold common fluid port. The locking connector may have a locking surface for attaching the manifold body to the fluid component, with the manifold common fluid port in fluid communication with the fluid component fluid port. The body may be rotatable relative to the locking connector. 
     The locking connector may include a fluid flow path. The locking connector fluid flow path may be in fluid communication with the manifold common fluid port. The manifold common fluid port may be annular, and the locking connector may extend longitudinally through the annular manifold common fluid port. 
     The manifold common fluid port may be defined between the body and the locking connector. The body may include a longitudinally extending opening, and the locking connector may be disposed in the opening. The manifold common fluid port may be disposed along the opening. The manifold common fluid port may include an annular groove disposed along the opening. The manifold individual fluid ports may extend radially from the opening. 
     The locking connector may include a fluid passage, and the fluid passage in the locking connector may include a longitudinally extending passage and a radially extending passage. The radially extending passage may be in fluid communication with the manifold common fluid port and with the longitudinally extending passage. The locking connector may include a stem, and the longitudinally extending passage and the radially extending passage may be disposed in the stem. The locking surface of the locking connector may include a threaded portion on an exterior surface of the stem, and the longitudinally extending passage may be disposed radially inwardly of the threaded portion. The locking connector may include a head, and the head may engage the body. 
     Annular seals may be disposed between the stem and the opening on longitudinally opposite sides of the passages in the body that extend from the individual fluid ports to the common fluid port. The annular seals may be disposed on longitudinally opposite sides of the radial passage in the stem. The locking connector may be rotatable relative to the body, and the radial passage in the stem may be in fluid communication with the common manifold fluid port in all rotatable positions of the manifold relative to the body. The locking connector is rotatable through 360 degrees relative to the body. 
     The fluid manifold may be arranged in combination with a fluid component, and the fluid component may be a hydraulic accumulator. The hydraulic accumulator may have a longitudinal axis, the body may have a longitudinal axis, and the axes may be co-axial. The hydraulic accumulator may include a shell having first and second ends and defining an interior volume, and a movable member may divide the interior volume into two variable volume chambers each of which includes an associated opening. One chamber may be adapted to receive a non-compressible fluid and the other chamber may be adapted to receive a charged gas. A closure assembly may close the opening to the charged gas chamber, and the closure assembly may include the fluid component port. The locking connector may removable attach the body to the closure assembly. 
     The locking connector may include a lock bolt having a stem portion through which a central fluid connector passage extends, and a plurality of radial passages may extend through the stem portion and interconnect with the central fluid connector passage. The lock bolt may further include a plurality of annular grooves, and each annular groove may receive an annular elastomeric seal. At least one of the annular grooves may be located between the plurality of radial passages and the head portion of the lock bolt. At least one of the annular grooves may be located between the plurality of radial passages and a threaded portion of the lock bolt. 
     The invention also provides various ones of the features and structures described the claims set out below, alone and in combination, and the claims are incorporated by reference in this summary of the invention 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of this invention will now be described in further detail with reference to the accompanying drawings, in which: 
         FIG. 1  is a side elevation view of a fluid manifold and fluid accumulator according to a preferred embodiment of this invention; 
         FIG. 2  is a cross sectional view of the fluid manifold and fluid accumulator illustrated in  FIG. 1 ; 
         FIG. 3  is an enlarged cross sectional view of the fluid manifold and one end of the fluid accumulator illustrated in  FIG. 1 ; 
         FIG. 4  is partially exploded perspective view of the fluid manifold illustrated in  FIG. 1 ; 
         FIG. 5  is an exploded side elevation view of the fluid manifold illustrated in  FIG. 1 ; 
         FIG. 6  is a cross sectional view taken along reference view line  6 - 6  in  FIG. 5 ; and 
         FIG. 7  is an enlarged view of the portion of  FIG. 6  indicated by reference view line  7 - 7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings in greater detail, the principles, embodiments and operation of the present invention are shown in the accompanying drawings and described in detail herein. These drawings and this description are not to be construed as being limited to the particular illustrative forms of the invention disclosed. It will thus become apparent to those skilled in the art that various modifications of the embodiments herein can be made without departing from the spirit or scope of the invention. 
       FIGS. 1 and 2  illustrates a fluid component  10  and a fluid manifold  12  constructed in accordance with the present invention. The fluid component  10  in the preferred embodiment is a hydraulic fluid accumulator. The fluid component or accumulator  10  and the fluid manifold  12  may be used in any suitable stationary or mobile hydraulic system. In the preferred embodiment, for example, the fluid accumulator  10  and fluid manifold  12  are used in a mobile vehicle hybrid hydraulic system. In this application, the accumulator  10  and manifold  12  are mounted on the vehicle (not shown). The accumulator  10  provides an energy storage device that receives and stores energy that may be generated during deceleration of the vehicle. The energy is stored as fluid under pressure, and the stored energy may be used at a later time by a component recipient of the fluid energy. For example the component recipient that uses the stored energy may be a hydraulic motor that causes movement of a component of a hydraulically operated boom or that is connected to the drive wheels of the vehicle to propel the vehicle. 
     The accumulator  10  and gas manifold  12  are longitudinally co-axial along a longitudinal axis  14 . The accumulator  10  includes a shell  16  that defines an interior volume. The shell  16  may be made of any suitable material for containing fluid under pressure. In one embodiment, the shell  16  is made from steel. In the embodiment illustrated in the drawings, the shell  16  is made from a suitable carbon fiber and resin composite material. A liner  18  is attached to the shell  16 . The liner  18  is of any suitable material, and in the preferred embodiment the liner  18  is of a high density polyethylene material. The shell  16  has opposite first and second ends  26  and  28 . As further described below, the first end  26  provides a hydraulic fluid pressure end of the accumulator  10 , and the second side  28  provides a charged gas end of the accumulator  10 . The end  26  includes a hydraulic fluid pressure annular end piece  30 , and the end  28  includes a charged gas annular end piece  32 . The hydraulic fluid pressure end piece  30  has a threaded interior surface that defines an opening. The liner  18  is attached to the end pieces  30  and  32  and prevents fluid escape from the shell  16 . 
     The opening of the shell  16  at the hydraulic fluid pressure end  26  is closed by a first end closure assembly  36 , illustrated as a port block assembly that is threadedly inserted into the threaded interior surface of the end piece  30 . The illustrated port block assembly  36  includes a spring  38  that biases a valve poppet  40  toward an opened position. As described further below, the port block assembly  36  is adapted to enable flow of hydraulic fluid into and out of a variable volume defined inside the liner  18  of the shell  16 . The opening of the shell  16  at the second end  28  is closed by a second end closure assembly  44  that is joined to the end piece  32  by a clearance fit. The second closure assembly  44  illustrated is adapted to support an open end portion  50  of an expandable bladder  52  and to provide a component fluid port that enables a flow of the charged gas into and out of the interior of the supported bladder  52 . The bladder  52  is of any suitable elastomeric polymeric material, and in the preferred embodiment the bladder  52  is of low temperature nitrile material. The bladder  52  divides the volume of the shell  16  into two variable volume chambers. As illustrated in  FIG. 2 , one chamber  56  is located within the bladder  52  and the other chamber  58  is located outside the bladder  52  and between the bladder  52  and the liner  18  of the shell  16 . 
     As is known in the art, the bladder  52  is filled with a charged gas, typically to a predetermined charge pressure, and remains under pressure during operation of the accumulator  10 . As hydraulic fluid enters chamber  58  to store energy as fluid under pressure, for example when the above described vehicle is decelerating, the charged gas in the bladder  52  is compressed. During this mode of operation, the volume of the hydraulic fluid chamber  58  expands and the volume of the charged gas chamber  56  and bladder  52  contract in size. The charged gas in the chamber  56  maintains the pressure of the stored hydraulic fluid in the chamber  58 . When the energy stored in the hydraulic fluid is to be used during another mode of operation, the hydraulic fluid exits from the chamber  58 . During this mode of operation, the volume of the charged gas chamber  56  and bladder  52  expands to reduce the pressure of the charged gas in the bladder back to the charge pressure and the volume of the hydraulic fluid chamber  58  decreases. When the bladder  52  expands a sufficient distance so as to close the poppet  40 , further fluid flow from the chamber  58  is prevented. 
     In this manner, the end piece  30  provides access for hydraulic fluid flow to and from the hydraulic fluid chamber  58  of the accumulator  10  defined between the liner  18  and the bladder  52 . The end piece  32  provides access for charge gas into the charged gas chamber  56  of the accumulator  10  inside the bladder  52 . Due to the repeated expansion and contraction of the bladder  52  during operation, which may occur at high and low operating temperature extremes, the accumulator  10  may be periodically removed and replaced during servicing of the hydraulic system in which the accumulator  10  is used. The manifold  12  facilitates this removal and replacement, as further described below. 
     Referring now to  FIG. 3 , the second closure assembly  44  and the fluid manifold  12  are illustrated. The second closure assembly  44  includes fluid component port member  70  that defines a fluid passage  72 . The fluid passage  72  provides a fluid port for the fluid component or accumulator  10 . The fluid component port member  70  includes a head portion  74  defined by a radially outwardly extending flange at a first end and a threaded exterior surface  76  near a second, opposite end. The fluid passage or port  72  of the fluid component port member  70  adjacent the second end inciudes a stepped portion that widens the passage  72  at the second end of the fluid component port member  70 . A threaded interior surface  78  is provided at the right end of the fluid passage  72  as viewed in  FIG. 3 . 
     The second closure assembly  44  further includes a bottom or longitudinally inner gas plug  84  and a top or longitudinally outer gas plug  86 . The top gas plug  86  is joined by a clearance fit to the end piece  32  so that a head portion  88  of the top gas plug  86  abuts against an end surface of the end piece  32 . The bottom gas plug  84  supports an anti-extrusion ring  94  and, when the second closure assembly  44  is assembled, abuts against the top gas plug  86 . The bladder  52  includes the open end portion  50  that is received by the head portion  74  of the fluid component port member  70  so as to align an opening in the bladder  52  with the fluid passage or port  72  in the fluid component port member  70 . In the assembled second closure assembly  44 , the opened portion  50  of the bladder  52  is held securely between the head portion  74  of the fluid component port member  70  and the bottom gas plug  84  by a tension created by tightening a jam nut  96  on the threaded portion  76  of the stem member such that the jam nut  96  abuts against the top gas plug  86 . 
     Referring now to  FIGS. 3-7 , the manifold  12  is affixed to the fluid component port member  70  of the second closure assembly  44  and provides a single point connection for connecting to the charged gas end  28  of the accumulator  10  the valves and fittings and components that are associated with the charged gas end  28 .  FIG. 4  is a partially exploded perspective view of the rotatable gas manifold  12  with its associated valves and fittings.  FIG. 5  is a partially exploded elevation view of the rotatable gas manifold  12  with its associated valves and fittings.  FIG. 6  is a cross-sectional view of the rotatable gas manifold  12  with its associated valves and fittings taken along reference view line  6 - 6  in  FIG. 5 .  FIG. 7  is an enlarged view of the portion of the gas manifold  12  in  FIG. 6  surrounded by the dashed line  7 - 7 . 
     Continuing with reference to  FIGS. 4-7 , the gas manifold  12  includes a body  102  that is a generally annular flat disk shaped member. The body  102  includes a longitudinally extending opening or central passage  104  that extends from side to side through the body  102  in a direction generally coaxial with the longitudinal axis  14 . A plurality of manifold individual fluid ports  112 ,  114  and  116  extend in a radial direction generally perpendicular to the longitudinal axis  14  outwardly from the opening  104  to the outer surface of the body  102 . Each of the fluid ports  112 ,  114  and  116  terminate at a threaded bore, two of which are illustrated in  FIG. 6 . Port  112  is adapted to receive a known standard threaded fitting  120  for connecting a known standard thermal relief valve  122  to the body  102  and opening  104  of the gas manifold  12 . Port  114  is adapted to receive a known standard high pressure unidirectional air valve assembly  126  for connection of the charged gas chamber  56  to a conduit (not shown) associated with an external air pressure source (not shown) for charging the chamber  56  of the accumulator  10  through the manifold  12 . The port  116 , illustrated as being located equidistance between ports  112  and  114 , receives a standard diagnostic test port fitting  130  for enabling diagnostic testing. Each port  112 ,  114  and  116  includes a radially extending passage  140 , two of which are shown in  FIG. 7 . The passages  140  establish fluid communication between each port  112 ,  114  and  116  and an enlarged diameter annular groove  142  that is disposed in and along a central portion of the primary passage or opening  104  of the body  102 . In the preferred embodiment, the annular groove  142  extends for a full circumferential distance of 360 degrees about the primary passage or opening  104  of the body  102 . Unless otherwise mentioned, the manifold  12  and its associated conduits and components are preferably of a suitable carbon steel material. 
     The gas manifold  12  also includes a generally cylindrical locking connector  150 , which is in the general shape of a lock bolt and provides a single point mechanical and fluid connection for the manifold  12  with the accumulator  10 . The locking connector  150  is rotatable through 360 degrees relative to the body  102 . In the preferred embodiment, the locking connector  150  has a stepped exterior surface and includes a locking connector stem portion  152  and a locking connector head portion  154 . The head portion  154  provides a wrench receiving exterior surface and has a larger diameter than the stem portion  152 . The head portion  154  is recessed into an enlarged diameter portion of the main opening  104  and engages the main body  102 . The stem portion  152  extends from the head portion  154  into and along the opening or passage  104  of the manifold body  102  and terminates with a smaller diameter portion  160  having a threaded exterior surface. The smaller diameter threaded portion  160  is adapted to be threadedly received in the passage  72  of the fluid component port member  70  for affixing the gas manifold  12  to the second closure assembly  44  of the fluid component or accumulator  10  with a single point connection. In an alternative embodiment not shown in the drawings, the head portion  154  could be formed as a flange that is connected to the main body  102  by two or more bolts that are separate from the stem portion  152  while the stem portion  152  and the annular groove  142  maintain the single point fluid connection of the manifold  12  to the accumulator  10 . 
     An intermediate generally cylindrical exterior portion  164  of the locking connector  150  is located on the stem portion  152  between the smaller diameter portion  160  and the head portion  154 . A plurality of radial passages  180 , two of which are illustrated in  FIG. 7 , extend from a central longitudinal connector passage  182  of the locking connector  150  radially outwardly to the groove  142  and the intermediate exterior portion  164  of the locking connector  150 . The intermediate portion  164  includes three annular grooves ( FIG. 7 ), two of which are disposed on longitudinally opposite sides of the passages  140 ,  180  for receiving standard annular seals  170 . The seals  170  are D-ring seals of a suitable elastomeric polymeric material, and in the preferred embodiment the seals  170  are of a polyurethane material. One of the seals  170  is disposed longitudinally intermediate the passages  140 ,  180  and the head portion  154 . Another of the seals  170  is disposed longitudinally intermediate the passages  140 ,  180  and the threaded portion  160 . The longitudinal connector passage  182  extends from the free end of the locking connector  150  at the small diameter portion  160  and intersects each of the radial passages  180 , to establish fluid communication between the groove  142  and the fluid component fluid port  72  in all rotational positions of the locking connector  150  relative to the body  102 . The passage  182  shown in the drawings is radially inward of the threaded portion  160 . The number of radial passages  180  may be varied as desired by a designer, however, the number preferably includes at least one radial passage  180  for every individual fluid port in the main body  102  of the gas manifold  12 . Preferably, the number of radial passage  180  outnumbers the number of ports in the main body  102  of the gas manifold  12 . As illustrated in  FIG. 7 , the seal grooves are disposed on each longitudinal side of each radial passage  180  and  140  for receiving a seal  170  that seals against the central opening  104  when the gas manifold  12  is assembled on the accumulator  10 . The annular groove  142  of the opening  104  in the body  102  and the intermediate portion  164  of the locking connector  150  cooperatively define a manifold common port  186  ( FIG. 7 ) along the opening  104 . The radially extending passages  180  establish fluid communication between the manifold common fluid port  186  and fluid component fluid port  72  through the longitudinally extending passage  182  in all rotational positions of the locking connector  150  relative to the body  102 . 
     When the gas manifold  12  is mounted to the second closure assembly  44  of the fluid component  10 , the locking connector  150  is disposed in the opening  104  in the body  102  and is threadedly connected to the port member  70 . A washer  200  is positioned between the head portion  154  of the lock bolt  150  and the main body  102  and, as the lock bolt  150  is tightened, the head portion  154  presses the main body  102  of the gas manifold  12  against the fluid component port member  70  for fixing the gas manifold relative to the accumulator  10 . At least one radial passage  180  in the lock bolt  150  aligns with each of the passages  140  or its associated groove  142  in the main body  102  such that the charged gas may pass through the ports to the radial passages  180  and central passage  182  to the passage or port  72  of the fluid component port member  70  and into the bladder  52  through opening. Should a position of the main body  102  need to be rotated, for example, so as to align valve assembly  126  with an associated conduit, the lock bolt  150  may be loosened and the body  102  rotated to its appropriate position. Once the body  102  is rotated to its appropriate position, the lock bolt  150  again is tightened for affixing the gas manifold  12  relative to the fluid component port member  70 . Again, radial passages  180  in the lock bolt  150  align with the ports in the main body  102  of the gas manifold  12 . The gas manifold  12  enables alignment of the various ports and associated valves without the need to disassemble the accumulator  10 , particularly the second closure assembly  44  of the accumulator  10 . 
     Presently preferred embodiments of the invention are shown and described in detail above. The invention is not, however, limited to these specific embodiments. Various changes and modifications can be made to this invention without departing from its teachings, and the scope of this invention is defined by the claims set out below. For example, instead of having a bladder  52 , the accumulator  10  may be a piston accumulator. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims. Also, while the terms first and second, one and another, left and right are used to more clearly describe the structure and operation of the manifold  12  and accumulator  10 , it should be understood these terms are used only for purposes of clarity and may be interchanged as appropriate. 
     Although the principles, embodiments and operation of the present invention have been described in detail herein, this is not to be construed as being limited to the particular illustrative forms disclosed. They will thus become apparent to those skilled in the art that various modifications of the embodiments herein can be made without departing from the spirit or scope of the invention.