Patent Publication Number: US-2023160384-A1

Title: Pump Assembly with Self-Retained Valve Spring and Methods

Description:
TECHNICAL FIELD 
     The present disclosure relates to pump assemblies and, in particular, valve assemblies for such pump assemblies. 
     BACKGROUND 
     In hydraulic fracturing, and other similar applications, the pumping equipment used to pump fluid media into a well is an important part of the fracturing system and process. Reciprocating pump assemblies have been used for decades to propel a fluid media, typically a mixture of water, sand and chemicals, for example, into a well at high pressures and flow rates. Increasing demands of pressure pumping has required such pumps to evolve by increasing in size, horsepower rating, and pressure capabilities. As a result, designing pump assemblies to be reliable and easily maintained has become an increasingly important consideration. 
     Reciprocating pump assemblies typically include fluid end blocks with fluid inlet and outlet passages for the fluid media. Each of the fluid inlets and fluid outlets include a check valve to control the flow of fluid through the fluid end block. The fluid inlet check valve is biased in a closed position against a valve seat of the fluid inlet passage by a biasing member, which conventionally is a spring. The spring is retained in position by a retainer or valve stop that is manually positioned and fitted to the inlet passage. The spring and retainer are manually installed with hand tools, typically by one person, which is a difficult to perform task. 
     Due the nature of the pumping process and high forces generated in the fluid end block, the valve stop can loosen and move. This creates the potential of damaging the fluid end block and creating stress risers and may lead to loss of retention of the spring biasing member. In the case of the latter situation, the loose spring may cause internal damage to the other elements of the end block and may be pumped out of the fluid end block and into the well, which may create other undesirable effects. 
     U.S. Pat. No. 10,240,597 discloses a pump assembly with a fluid block. The fluid block includes inlet and outlet passages, each with a check valve. The check valve for the inlet passage is configured to permit entry of fluid into the fluid block and is biased in a closed condition until a predetermined pressure differential is generated by the pump in the fluid block. The check valve is biased by a spring that is kept in position with a retainer that spans the inlet passage. The retainer can be difficult to install and can be dislodged or moved, which as noted above, can result in damage to the fluid end of the pump assembly. 
     The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the innovations described herein, nor to limit or expand the prior art discussed. Thus, the foregoing discussion should not be taken to indicate that any particular element of a prior system is unsuitable for use with the innovations described herein, nor is it intended to indicate that any element is essential in implementing the innovations described herein. The implementations and application of the innovations described herein are defined by the appended claims. 
     There is a need for an easily assembled and reliable biasing element for a fluid end of a pump assembly. Devices and methods according to the disclosure satisfy the need. 
     SUMMARY 
     In one aspect, the disclosure includes a fluid end of a reciprocating pump assembly and a reciprocating pump assembly having a power end wherein the fluid end includes a fluid end block defining a fluid chamber. A plunger is reciprocally disposed in the fluid chamber to generate fluid pressure therewithin. An outlet fluid passage is formed in the fluid end block in fluid communication with the fluid chamber. An inlet fluid passage formed in the fluid end block is in fluid communication with the fluid chamber. The inlet fluid passage includes a valve seat, an enlarged diameter downstream from the valve seat, and a neck downstream of the enlarged diameter. The neck has a lesser diameter than the enlarged diameter. An inlet valve is movably disposed in the inlet fluid passage and sized and shaped to seal against the valve seat and a biasing member has a first end with a first diameter disposed on the inlet valve and a second end with a second diameter disposed within the enlarged diameter and seated inside and against the neck. The second end diameter is greater than the neck so as to be retained thereby within the inlet fluid passage. 
     In another aspect, the disclosure includes a method of assembling an inlet valve for a fluid end of a reciprocating pump assembly, the method including enabling access to a chamber of the fluid end, installing an inlet valve into an inlet fluid passage of the fluid end, inserting a biasing member into the chamber, advancing the biasing member into a position within the inlet fluid passage by rotating the biasing member and into engagement with the inlet valve with a first end thereof, and wherein the biasing member is engaged with a neck of the inlet fluid passage with a second end thereof, whereby the shape size of the second end and the neck holds the biasing member in the inlet fluid passage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an elevation view of a reciprocating pump assembly according to an exemplary embodiment, the reciprocating pump assembly including a fluid end. 
         FIG.  2    is a section view of the fluid end of  FIG.  1    according to an exemplary embodiment, the fluid end including a fluid end block or housing and inlet and outlet valves. 
         FIG.  3    is a perspective view of a biasing member according to the disclosure. 
         FIG.  4    is a cut away perspective view of an inlet valve according to the disclosure. 
         FIG.  5    is a cut away perspective view of an inlet valve according to the disclosure with a biasing member shown in a partially installed condition. 
         FIG.  6    is a cut away side view of an inlet valve according to the disclosure with a biasing member shown in an installed condition. 
         FIG.  7    is a flow chart of a method of installing a biasing member into a fluid end according to the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Now referring to the drawings, wherein like elements refer to like reference numbers, there is illustrated in  FIG.  1    an exemplary embodiment of a reciprocating pump assembly (generally referred to by the reference numeral  10 ) including a power end portion  12  and a fluid end portion  14  operably coupled thereto. The power end portion  12  includes a housing  16  in which a crankshaft (not shown) is disposed, as is known, the crankshaft being operably coupled to an engine or motor (not shown), as is known, which is configured to drive the crankshaft. The fluid end portion  14  includes a fluid end block  18 , which is connected to the housing  16  via a plurality of stay rods  20 . The fluid end block  18  includes a fluid inlet passage  22  and a fluid outlet passage  24 , which are spaced in a parallel relation. A plurality of fluid end retainer nuts  26 , one of which is shown in  FIG.  1   , is connected to the fluid end block  18  opposite the stay rods  20 . A plurality of cover assemblies  28 , one of which is shown in  FIG.  1   , is connected to the fluid end block  18  opposite the fluid inlet passage  22 . A plunger rod assembly  30  extends out of the housing  16  and into the fluid end block  18 . 
     In embodiments, as illustrated in  FIG.  2    with continuing reference to  FIG.  1   , the plunger rod assembly  30  includes a plunger  32 , which extends through a bore  34  formed in the fluid end block  18 , and into a pressure chamber  36  formed in the fluid end block  18 . The plunger  32  is reciprocally disposed in the fluid chamber  36  to generate fluid pressure therewithin. In embodiments, a plurality of parallel-spaced bores may be formed in the fluid end block  18 , with one of the bores being the bore  34 , a plurality of pressure chambers may be formed in the fluid end block  18 , with one of the pressure chambers being the pressure chamber  36 , and a plurality of parallel-spaced plungers may extend through respective ones of the bores and into respective ones of the pressure chambers, with one of the plungers being the plunger  32 . 
     The fluid end block  18  includes inlet and outlet fluid passages  38  and  40  formed therein, which are generally coaxial along a fluid passage axis  42 . Under conditions to be described below, fluid flows from the inlet fluid passage  38  toward the outlet fluid passage  40  along the fluid passage axis  42 . The fluid inlet passage  22  is in fluid communication with the pressure chamber  36  via the inlet fluid passage  38 . The pressure chamber  36  is in fluid communication with the fluid outlet passage  24  via the outlet fluid passage  40 . 
     The inlet fluid passage  38  includes an enlarged-diameter portion  38   a  and a reduced-diameter portion  38   b  extending downward therefrom (as in the figure), which direction may also be considered the upstream direction. Downstream from the enlarged-diameter portion  38   a  is an inlet fluid passage neck  38   c , which is reduced in diameter relative to the enlarged-diameter portion. 
     The enlarged diameter portion  38   a  defines a tapered internal shoulder  43  and thus a frusto-conical surface  44  of the fluid end block  18 . The reduced-diameter portion  38   b  defines an inside surface  46  of the fluid end block  18 . Similarly, the outlet fluid passage  40  includes an enlarged-diameter portion  40   a  and a reduced-diameter portion  40   b  extending downward therefrom. The enlarged-diameter portion  40   a  defines a tapered internal shoulder  48  and thus a frusto-conical surface  50  of the fluid end block  18 . The reduced-diameter portion  40   b  defines an inside surface  52  of the fluid end block  18 . The frusto-conical surfaces  44 ,  50  form valve seats for respective inlet and outlet valves  54 ,  56 . 
     An inlet valve  54  is disposed in the inlet fluid passage  38 , and engages at least the frusto-conical surface  44  and the inside surface  46 . Similarly, an outlet valve  56  is disposed in the outlet fluid passage  40 , and engages at least the frusto-conical surface  50  and the inside surface  52 . In an exemplary embodiment, each of valves  54  and  56  is a spring-loaded valve that is actuated by a predetermined differential pressure thereacross. 
     A counterbore  58  is formed in the fluid end block  18 , and is generally coaxial with the outlet fluid passage  40  along the fluid passage axis  42 . In embodiments, the fluid end block  18  may include a plurality of parallel-spaced counterbores, one of which may be the counterbore  58 , with the quantity of counterbores equaling the quantity of plunger throws included in the pump assembly  10 . The cover assembly  28  shown in  FIGS.  1  and  2    includes at least a plug  64  and a fastener  66 . In embodiments, the cover assembly  28  may be disconnected from the fluid end block  18  to provide access to, for example, the counterbore  58 , the pressure chamber  36 , the plunger  32 , the outlet fluid passage  40  or the outlet valve  56 . In embodiments, the pump assembly  10  may include a plurality of plugs, one of which is the plug  64 , and a plurality of fasteners, one of which is the fastener  66 , with the respective quantities of plugs and fasteners equaling the quantity of plunger throws included in the pump assembly  10 . 
     A counterbore  60  is formed in the fluid end block  18 , and is generally coaxial with the bore  34  along an axis  62 . The counterbore  60  defines an internal shoulder  60   a  and includes an internal threaded connection  60   b  adjacent the internal shoulder  60   a . In embodiments, the fluid end block  18  may include a plurality of parallel-spaced counterbores, one of which may be the counterbore  60 , with the quantity of counterbores equaling the quantity of plunger throws included in the pump assembly  10 . 
     A plug  68  is disposed in the counterbore  60 , engaging the internal shoulder  60   a  and sealingly engaging an inside cylindrical surface defined by the reduced-diameter portion of the counterbore  60 . In an exemplary embodiment, the plug  68  may be characterized as a suction cover. An external threaded connection  70   a  of a fastener  70  is threadably engaged with the internal threaded connection  60   b  of the counterbore  60  so that an end portion of the fastener  70  engages the plug  68 . As a result, the fastener  70  sets or holds the plug  68  in place against the internal shoulder  60   a  defined by the counterbore  60 , thereby maintaining the sealing engagement of the plug  68  against an inside cylindrical surface  61  defined by a reduced-diameter portion  60   c  of the counterbore  60 . The retainer nut  26  shown in  FIGS.  1  and  2    includes at least the plug  68  and the fastener  70 . In embodiments, the retainer nut  26  may be disconnected from the fluid end block  18  to provide access to, for example, the counterbore  60 , the pressure chamber  36 , the plunger  32 , the inlet fluid passage  38 , or the inlet valve  54 . The retainer nut  26  may then be reconnected to the fluid end block in accordance with the foregoing. In several exemplary embodiments, the pump assembly  10  may include a plurality of plugs, one of which is the plug  68 , and a plurality of fasteners, one of which is the fastener  70 , with the respective quantities of plugs and fasteners equaling the quantity of plunger throws included in the pump assembly  10 . 
     Focusing now on the inlet fluid passage  38 , a biasing member  71  is positioned within the inlet fluid passage  38 . The biasing member  71  may be a coil spring as depicted or may be an equivalent biasing element, such as wave spring. In one embodiment the biasing member  71  is a conical coil spring. In some examples, the biasing member  71  may be a coil or other type of spring having an hourglass shape. In some examples, a cross-section of the biasing member  71  may be round, square, rectangular, or flat (e.g., shaped like a leaf spring). 
     Referring also to  FIGS.  3 - 6   , the biasing member  71  includes a first end  72  with a first diameter and a second end  74  with a second diameter, where the first diameter is less than the second diameter. It will be understood that since the illustrated exemplary biasing member  71  is shown as a helical coil that the diameters of the first and second ends are measured laterally relative to the centerline shape of the coil, e.g., radially relative to the centerline  73  ( FIG.  3   ). 
     The first end  72  is positioned adjacent and in contact with the inlet valve  54  ( FIG.  2   ). The inlet valve  54  may have an inlet valve boss  76  ( FIG.  5   ) that is sized and shaped to receive and retain the first end  72  of the biasing member  71 . In an embodiment, the inlet valve boss  76  is a cylindrical protrusion, projection, post, lug, dowel, or shaft, for example, that receives and retains the coiled first end  72 . 
     The second end  74  is sized such that when positioned within the enlarged diameter portion  38   a , the relatively reduced diameter of the inlet fluid passage neck  38   c  traps the biasing member  71  within the inlet fluid passage  38  without any requirement for a retainer/valve stop. As shown in  FIG.  2   , the second end diameter of the biasing member  71  (e.g., an outer diameter at the second end  74 ) is greater than an inner diameter of the neck  38   c . It will be understood, therefore, that the geometry of the inlet valve passage  38 , in combination with the size and shape of the biasing member  71 , forms a means of preventing the biasing member  71  from being displaced from its installed position within the inlet valve passage  38  without the need for a separate retainer. As shown in  FIG.  6   , the biasing member  71  may be positioned so as to retain the second end  74  inside and against the neck  38   c  when installed. 
     The biasing member  71  also has a gripping section or tang  78  formed at the second end  74  ( FIG.  4   ). The tang  78  may extend at any angle relative to the centerline. In the example shown in  FIG.  4   , the tang  78  of the biasing member  71  extends in a direction that is normal to the centerline, i.e., radially relative to the centerline  73  ( FIG.  3   ). The tang  78  is used by gripping with a tool to install the biasing member  71  into the inlet fluid passage  38  much in the same fashion as installing a Heli-Coil. The normal angle of the tang  78  shown in  FIG.  4    may simplify the tool design for gripping the tang  78 . The tang  78  may be a straight section formed of the spring material that constitutes the spring or it may be a thickened section of spring material. The tang  78  may extend from one side of the coil to the other in a generally radial direction to provide a gripping means without interfering with or potentially damaging the actual spring part of the biasing member  71 . While there is no need in the present device to provide the biasing member  71  with a self-tapping feature, it will be understood that the helical shape of the biasing member enables the installation thereof by a threading process or procedure into the inlet fluid passage  38  until the entire body of the biasing member  71  is contained with the passage. In effect, the shape and size of the neck  38   c  functions as an internal thread into which the coil spring shape of the biasing member  71  may be threadably inserted into the inlet fluid passage  38 . The tool (not shown) may have a gripping end or hole that grips or satisfactorily receives the tang  78 . It is also contemplated that the biasing member  71  could be installed manually, whereby the tang  78  could be manually gripped and rotated by hand should the openings in the fluid end  14  permit. 
     When installed as shown in  FIG.  2   , the biasing member  71  exerts a selected biasing force on the inlet valve  54  that holds the inlet valve against the frusto-conical surface  44  to create a closed or sealed condition. When a pressure differential on the inlet valve  54  exceeds the closing force generated by the biasing member  71 , the inlet valve opens and permits fluid media to enter the fluid chamber  36 . 
     Referring again to  FIG.  2   , a biasing member  81  is positioned within the outlet fluid passage  40 . The biasing member  81  may be any type of spring described above in relation to the biasing member  71 . The biasing member  81  includes a first end positioned adjacent and in contact with the outlet valve  56  with a first diameter and a second end positioned adjacent and in contact with the plug  64  with a second diameter, where the first diameter is less than the second diameter. 
     INDUSTRIAL APPLICABILITY 
     The industrial applicability of the system described herein will be readily appreciated from the forgoing discussion. The foregoing discussion is applicable to fluid ends of reciprocating pump assemblies, in particular, for pumping fluid media in fracturing operations and similar applications. 
     One example of the industrial application of the system according to embodiments of the disclosure, and referring also to  FIGS.  1 - 6   , a method of installing a biasing member  71  into an inlet fluid passage  38  is illustrated in  FIG.  7   . Step  100  illustrates a step wherein the biasing member  71  is installed through the opening normally occupied by the cover assembly  28 . With the cover assembly and outlet valve removed, the chamber  36  may be inspected or visually checked or cleaned/treated to ensure that there is no debris or undesirable material in the chamber. Strictly speaking, the inspection step may not be necessary, but it will be understood that debris in the chamber  36  may interfere with proper positioning of the internal components of the fluid end  14 . The chamber  36  is also checked and any necessary adjustments made to the position of the plunger  32  to ensure clear access to the interior of the fluid end block  18 . 
     Alternatively, step  102  illustrates a step wherein the biasing member  71  is installed through the opening normally occupied by the retainer nut  26 . With the retainer nut  26  removed, the chamber  36  may be visually checked or treated to ensure that there is no debris or undesirable material in the chamber. The chamber  36  is also checked and any necessary adjustments made to the position of the plunger  32  to ensure clear access to the interior of the fluid end block  18 . 
     The inlet valve  54  is positioned within the inlet fluid passage  38  in step  104  regardless of the direction of access to the chamber  36 . The biasing member  71  may be grasped by the tang  78  in step  106 . The biasing member  71  is inserted into the chamber  36  with the narrow, first end  72  oriented toward the boss  76  of the installed inlet valve  54  in step  108 . 
     The biasing member  71  is rotated in a direction that enables the biasing member to engage the neck  38   c  of the inlet fluid passage  38  and permit advancement of the biasing member into the enlarged diameter  38   a  of the inlet fluid passage by threading the biasing member through the neck in step  110 . When the first end  72  is brought into contact with the inlet valve  54  and the second end  74  is threaded fully within the enlarged diameter  38   a  of the inlet fluid passage  38 , and the entire biasing member  71  is captured within the inlet fluid passage the installation is completed. In the installed position, the biasing member  71  exerts a specified preload on the inlet valve  54 . 
     As described above, the biasing member  71  can be installed within the inlet fluid passage  38  without any requirement for a separate retainer/valve stop. Therefore, embodiments disclosed herein can reduce risks associated with cracking, loosening and/or loss of a separate retainer/valve stop. Furthermore, methods of installing the biasing member  71  into an inlet fluid passage  38  described herein may be safer and/or faster compared to methods associated with the installation of a separate retainer/valve stop. 
     It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. 
     Unless explicitly excluded, the use of the singular to describe a component, structure, or operation does not exclude the use of plural such components, structures, or operations or their equivalents. The use of the terms “a” and “an” and “the” and “at least one” or the term “one or more,” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B” or one or more of A and B″) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B; A, A and B; A, B and B), unless otherwise indicated herein or clearly contradicted by context. Similarly, as used herein, the word “or” refers to any possible permutation of a set of items. For example, the phrase “A, B, or C” refers to at least one of A, B, C, or any combination thereof, such as any of: A; B; C; A and B; A and C; B and C; A, B, and C; or multiple of any item such as A and A; B, B, and C; A, A, B, C, and C; etc. 
     Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.