Abstract:
A suction block for use in a fluid end assembly of a high pressure reciprocal pump includes a first suction bore extending from a first face of the suction block and into the interior thereof; and a second suction bore extending from a second face of the suction block and into the interior thereof to intersect the first suction bore. The second suction bore is adapted to receive a valve assembly for alternatively fluidly connecting and disconnecting the first and second suction bores. The first suction bore has a first suction bore section with a first geometry and a second suction bore section with a second geometry different from the first geometry to thereby reduce stress in the suction block during use.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/852,762 filed on Mar. 21, 2013, the disclosure of which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to high pressure pumps, and more particularly to the fluid end of such pumps. 
         [0003]    High-pressure reciprocating fluid pumps have been used for many years in various industries to pressurize incompressible fluids to pressures upwards of 10 kpsi. A primary use of such pumps is for pumping drilling fluid downhole, such as mud, during oil well drilling. Such pumps are also used to provide pressurized fluid for fracking operations, water-blasting, slurry transport for oil fields, coal slurry transport from a mine to a power station, and other applications where liquids with high solid content must be transported from one location to another. 
         [0004]    Because of the cyclic pressures (atmospheric to 10 kpsi or more) of these high pressure reciprocating fluid pumps, and the use of abrasive process fluids, the operating environment of such pumps is very demanding. Because of the high cyclical pressures encountered in the fluid end portions of these pumps, their components, such as the suction module and valves are susceptible to fatigue failure and wear. 
         [0005]    Moreover, the suction modules of the fluid end portions of many high-pressure reciprocating pumps require cross-bores, which intersect the pump cylinder, to deliver and carry away the process fluid. These intersecting cross-bores create stress concentrations, and thus further contribute to fatigue failure of the suction modules of the fluid end portions of such pumps. Thus, many known fluid end portions require high-strength materials in an attempt to avoid fatigue failure. U.S. Pat. No. 3,260,217 to Thresher, for example, discloses a typical fluid end portion having intersecting cross-bores. 
         [0006]    Moreover, because of high pump pressures, leakage from such pumps becomes a problem when the valves begin to wear. Some known pumps use the pressure of the process fluid to hydrostatically bias the valve assembly in engagement with the connector block or cylinder. These pumps require heavy discharge manifolds to contain the high pressure encountered and are still susceptible to fatigue failure and wear. The weight and bulk of these discharge manifolds requires more than one person to remove the manifold for repair of the fluid end portion of the pump. Such configurations are therefore labor-intensive, time-consuming, and result in expensive downtime of the fluid pump. Since the repairs must be made at the site of the fluid pump, and thus at the sight of down-hole operations and so on, exposure to adverse weather conditions further contributes to the difficulties associated with removal and replacement of the worn or broken parts. 
         [0007]    It would therefore be desirable to provide a fluid end portion that reduces the operating stresses of the suction module of the fluid end portion of high-pressure reciprocating pumps to thereby overcome one or more of the afore-mentioned disadvantages of the prior art. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    According to one aspect of the invention, a fluid end assembly for use in a high pressure reciprocal pump includes a discharge valve module having a discharge block with a first discharge bore fluidly connectable to a second discharge bore; and a suction valve module having a suction block connectable to the discharge block with a first suction bore fluidly connectable to the first discharge bore and a second suction bore fluidly connectable to the first suction bore. The first suction bore has a first suction bore section that matches the shape of the first discharge bore for coupling therewith. A second suction bore section has a different shape from the first suction bore section to thereby reduce stress in the suction valve module during use. 
         [0009]    According to a further aspect of the invention, a suction block for use in a fluid end assembly includes a first suction bore extending from a first face of the suction block and into the interior thereof; and a second suction bore extending from a second face of the suction block and into the interior thereof to intersect the first suction bore. The second suction bore is adapted to receive a valve assembly for alternatively fluidly connecting and disconnecting the first and second suction bores. The first suction bore has a first suction bore section with a first geometry and a second suction bore section with a second geometry different from the first geometry to thereby reduce stress in the suction block during use. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The foregoing summary as well as the following detailed description of the preferred embodiments of the present invention will be best understood when considered in conjunction with the accompanying drawings, wherein like designations denote like elements throughout the drawings, and wherein: 
           [0011]      FIG. 1  is a front isometric view of a fluid end portion in accordance with the invention that forms part of a high pressure reciprocal pump; 
           [0012]      FIG. 2  is an exploded front isometric assembly view thereof; 
           [0013]      FIG. 3  is an isometric sectional view thereof taken along line  3 - 3  of  FIG. 1 ; 
           [0014]      FIG. 4  is similar to  FIG. 3  showing an elevational isometric sectional view thereof; 
           [0015]      FIG. 5  is a side elevational view of a suction module in accordance with the invention that forms part of the fluid end portion; 
           [0016]      FIG. 6  is a sectional view taken along line  6 - 6  of  FIG. 5  and showing an further embodiment of the suction module; 
           [0017]      FIG. 7A  is an isometric sectional view similar to the  FIG. 6  cross-section; 
           [0018]      FIG. 7B  is a sectional view similar to  FIG. 6  with the hidden lines removed; 
           [0019]      FIG. 8A  is an isometric sectional view of a prior art suction module; 
           [0020]      FIG. 8B  is a rear sectional view similar to the  FIG. 8  cross-section; 
           [0021]      FIG. 9  is an isometric sectional view similar to  FIG. 7A  showing stress analysis of the suction module of the invention; and 
           [0022]      FIG. 10  is an isometric sectional view similar to  FIG. 8A  showing stress analysis of a prior art suction module. 
       
    
    
       [0023]    It is noted that the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope thereof. It is further noted that the drawings are not necessarily to scale. The invention will now be described in greater detail with reference to the accompanying drawings. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    Referring to the drawings, and to  FIGS. 1-4  in particular, a fluid end assembly  10  that forms part of a high-pressure reciprocating pump is illustrated. A typical, high-pressure, reciprocating fluid pump comprises two major assemblies, namely a power end assembly (not shown), and a fluid end assembly, which is the subject matter of the present invention. The fluid end assembly  10  is connected to the power end assembly in a well-known manner for driving a reciprocating plunger (not shown) associated with the fluid end assembly  10  for transporting liquids with high solid content from one location to another. Such power end assemblies are well known in the art and therefore will not be further elaborated on. 
         [0025]    The fluid end assembly  10 , in accordance with the invention, preferably includes a fluid discharge module  14  and a suction module  16  connected to the fluid discharge module  14 . 
         [0026]    As shown, the fluid discharge module  14  preferably includes a single-piece block  18  which can be formed by a single forging and/or machined from a block of high strength alloy or other suitable materials. The fluid discharge module  14  typically includes a first discharge bore  22  extending between a first face  24  and a second opposing face  26  and is operatively associated with a reciprocating plunger (not shown) in a well-known manner for receiving fluid being pumped through the suction valve module  16 . The fluid is pumped through a second transverse discharge bore or port  28  that extends inwardly from a third face  30  ( FIG. 1 ). The second bore  28  preferably extends at approximately 90 degrees with respect to the first bore  22  and is in fluid communication with the first bore  22 . 
         [0027]    In accordance with a further embodiment of the invention, although a single first bore, second bore, suction module, and discharge module are shown, it will be understood that the fluid discharge block  18  can have a plurality of first bores  22  formed therein operatively associated with an equal number of reciprocating plungers and each being in fluid communication with a separate suction module  16 . For example, typical high-pressure, reciprocating fluid pumps may have a plurality of cylinders, such as three or five cylinders. Such pumps are referred to as triplex or quintuplex pumps, respectively. Accordingly, it will be understood that the present invention is not limited to a single fluid transfer configuration. 
         [0028]    The fluid discharge module  14  further includes a discharge valve bore formed in the fluid discharge block  18  between a fourth face  34  (that is generally perpendicular to the first, second and third faces of the block  18 ) and the first discharge bore  22  and a discharge valve assembly  36  installed in the discharge valve bore  32 . The discharge valve assembly  36  opens when the plunger (not shown) applies pressure to the fluid in the first bore  22  to thereby open a fluid passageway between the first bore  22  and the second bore  28  for discharging the fluid under pressure. 
         [0029]    The discharge valve assembly  36  is preferably of the mechanically actuated type, but it will be understood that any suitable valve assembly can be used, including other mechanical and/or electronic valve assemblies. In the present exemplary embodiment, the discharge valve assembly  36  includes a discharge valve seat  40  is positioned in the discharge valve bore  32  against a shoulder  42  formed in the bore  32 . A discharge valve  44  is also positioned in the discharge valve bore  32  and is normally biased against the valve seat  40  by a compression spring  46  that extends between the valve  44  and an upper valve guide  48  in a well-known manner to prevent reverse flow of fluid through the discharge valve bore  32  during the outward or “suction” stroke of the plunger (not shown). The upper valve guide  48  is preferably positioned in the discharge valve bore  32  and connected to an end cap  50  which is in turn positioned within the bore  32  and rests against an upper shoulder  52  formed in the bore  32 . An O-ring or similar seal  49  is located between the bore  32  and the end cap  50  for sealing the valve assembly  40  to the block  18  in a well-known manner. A locking ring  54  with a central internally threaded bore  56  is mounted to the face  34  of the block  18 . Threaded studs  58  extend through circumferentially spaced openings or bores  60  and thread into internally threaded circumferentially spaced bores  62  formed in the face  34  of the block  18 . Nuts  64  thread onto the studs  58  and press against the locking ring  54  for holding the valve assembly  36  together in the bore  32 . A sleeve  66  with external threads  68  is threaded into the bore  56  of the locking ring  54  in a well-known manner. The particular construction of the discharge valve assembly  36  does not form part of the present invention other than illustrating how the fluid end assembly  10  will function during operation. Accordingly, the fluid discharge module  14  as well as the discharge valve assembly  36  can be provided in a wide variety of shapes, configurations, and operating modes without departing from the spirit and scope of the invention. 
         [0030]    With reference now to  FIGS. 2-6 , the suction module  16  preferably includes a single piece suction valve block  70  which can be formed by a single forging and/or machined from a block of high strength alloy or other suitable materials. The suction valve block  70  is preferably mounted to the second face  26  of the fluid discharge block  18  via six threaded studs  72  (best shown in  FIG. 2 ) that extend through an equal number of openings or bores  74  extending through the block  70  between a first face  76  and opposing second face  78 , then thread into an equal number of threaded openings or bores  80  formed in the second face  26  of the fluid discharge block  18  such that the second face  26  of the discharge block  18  abuts the second face  78  of the suction block  70  (best shown in  FIGS. 3 and 4 ). Nuts  82  thread onto the studs  72  to securely fasten the suction valve block  70  to the fluid discharge block  18 . It will be understood that more or less studs and/or other connection means can be used without departing from the spirit and scope of the invention. It will be further understood that the suction valve block  70  can be mounted to the fluid discharge block  18  through other connecting means, such as mutually engaging locking surfaces, retaining rings, clamps, or other well-known connection means, without departing from the spirit and scope of the invention. 
         [0031]    A first suction bore  84  extends into the block  70  from the second face  78  and is coaxial with the first discharge bore  22  of the discharge block  18 . An annular seal  86  is located in an annular groove  87  ( FIG. 3 ) formed in the second face  26  of the discharge block  18 . The annular seal  86  presses against the second face  78  of the fluid suction block  70  to thereby seal the first suction bore  84  to the first discharge bore  22 . A second suction bore  88  extends into the suction block  70  between a third face  90  and a fourth face  92  of the block  70 . The second suction bore  88  preferably extends at an angle of approximately 90 degrees with respect to the first suction bore  84  and is in fluid communication therewith. 
         [0032]    The fluid suction module  16  further includes a suction valve assembly  96  installed in the second suction valve bore  88 . The suction valve assembly  96  is similar in construction to the discharge valve assembly  36  and thus has similar numerals denoting similar parts. Accordingly, the details of the suction valve assembly  96  will not be further discussed. 
         [0033]    The suction valve assembly  96  opens when the plunger (not shown) applies suction to the fluid in the first discharge bore  22  of the discharge block  18  and in the first suction bore  84  of the suction block  70  to thereby open a fluid passageway between the second suction bore  88  and the first discharge bore  22  for receiving more fluid under vacuum pressure that is subsequently discharged through the second discharge bore  28  when the plunger (not shown) is moved in the opposite direction. Thus, when the plunger (not shown) moves to cause fluid travel to the right, as denoted by arrow  98  in  FIG. 7 , the suction valve opens and the discharge valve remains closed. When the plunger (not shown) moves to cause fluid travel to the left, as denoted by arrow  100  in  FIG. 4 , the suction valve closes under positive pressure and the discharge valve opens under the positive pressure to discharge the fluid through the discharge port  28 . During this cyclical movement, the stress exerted on the inner faces of the bores of prior art suction modules can be upwards of 27 Kpsi, as shown in  FIG. 10 , especially at the 90 degree transition area  2  ( FIGS. 8A and 8B ) of a prior art suction block  4  between a first suction bore  6  and a second suction bore  8  thereof, thus resulting in early failure of the fluid suction module and/or components of the fluid suction module, such as the suction valve assembly. 
         [0034]    In order to reduce the amount of cyclic stress on the inner walls of the suction module  16  and in accordance with the invention, as best shown in  FIGS. 5-7 , the first suction bore  84  preferably includes a first suction bore section  102  that has a circular cross sectional area  106  and a second suction bore section  104  that has a slotted cross sectional area  108  that is longer than the diameter of the circular area along an axis  110  and narrower than the diameter of the circular area along an axis  112 . 
         [0035]    As shown in  FIG. 6 , and in accordance with a further embodiment of the invention, the first bore section  102  converges smoothly towards the second suction bore  88 . A lower shoulder  114  and an upper shoulder  116  of the first suction bore  84  define a transition area between the first bore section  102  and second bore section  104 . At the face  78  of the suction block  70 , the first suction bore section  102  is preferably of the same size and circular shape as the first discharge bore  22  of the discharge block  18  so that the bores mate together. 
         [0036]    In accordance with an exemplary embodiment of the invention, the suction bore  88  may be seven inches in diameter while the discharge bore  22  may be four inches in diameter. The first suction bore section  102  would have a dimension “A” ( FIG. 5 ) of four inches in diameter to match the size and shape of the discharge bore  22 . The slotted portion  108  of the second suction bore section  104  would have a height “H” of approximately two inches, for example, and a width “W” of about seven inches long, for example, including the radiused ends  118  and  120  ( FIG. 5 ). Preferably, the cross sectional area of the slotted portion  108  is at least approximately equal to the cross sectional area of the first suction bore section  102 , and thus the first discharge bore  22 . In this manner, the block  70  has additional material where the highest stresses are located without impeding the flow of the liquid slurry. As best shown in  FIG. 9 , in accordance with the exemplary embodiment of the invention, the maximum stress experienced by the suction block  70  is approximately 19 kpsi, which is a significant reduction in stress over the prior art. 
         [0037]    It will be understood that the size and shape of the slotted portion  108  as well as the size and shape of the internal bores can have a great amount of variance without departing from the spirit and scope of the invention. 
         [0038]    Accordingly, the varying width of the first suction bore  84  reduces the operating stress of the suction module  16  in the fluid end  10  of a pump by forming a tangential intersection (see  FIG. 7 ) of the second suction bore  88  and the first suction bore  84 . Another benefit of the varying width suction bore  88  is increased reinforcement near the areas of highest stress. Yet another benefit of the varying width suction bore  88  is reduced pump shut down time due to maintenance, as the life of the suction module  16  is increased. A further benefit of the varying width suction bore  88  is improved fluid dynamics. Yet a further benefit of the suction module  16  is that it can be easily removed from the discharge module  14  by removing the six nuts  82  and sliding the suction module  16  off the studs  72  and replaced by another suction module  16  by sliding the new module over the studs  72  and installing the nuts  82  thereon. 
         [0039]    It will be understood that the term “preferably” as used throughout the specification refers to one or more exemplary embodiments of the invention and therefore is not to be interpreted in any limiting sense. It will be further understood that the term “connect” and its various derivatives as may be used throughout the specification refer to components that may be joined together either directly or through one or more intermediate members. In addition, terms of orientation and/or position as may be used throughout the specification relate to relative rather than absolute orientations and/or positions. 
         [0040]    It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. For example, the suction block and the discharge block can be made by forging and/or machining from a single block of material. Moreover, the transition from the slotted bore section  104  to the round bore section  102  need not occur only in the suction module. The transition could take place in the discharge module by modifying the bore  22  and removing the round bore section  102 . Furthermore, the same geometry as disclosed herein may be employed in any high pressure environment where fluid and/or slurry must pass through a bend or elbow to thereby reduce the stresses on the surrounding structure. It will be understood, therefore, that this invention is not limited to the particular embodiments disclosed, but is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.