Patent Abstract:
The present invention discloses a multi-component valve system for use in pumps such as fracking pumps for use in subterranean resource production. The assembly includes a retaining pin, a guide on the retaining pin, a valve on the retaining pin, an insert on the retaining pin, a retainer above the insert on the retaining pin, and a retainer cap inertia welded to the end of the retaining pin. In a particular embodiment, the guide component is stamped and folded to create the desired shape.

Full Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 14/213,696 filed Mar. 14, 2014, now U.S. Pat. No. 9,470,226 issued Oct. 18, 2016, which claimed the benefit of U.S. Provisional Application No. 61/785,246 filed Mar. 14, 2013, the disclosures of which are hereby incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD OF INVENTION 
       [0002]    The present invention relates to a valve assembly for use in reciprocating, positive displacement pumps, such as mud pumps, well service pumps, and other industrial applications. More particularly, the present invention is especially suitable for use in a fracking pump for subterranean production services. More specifically, the present invention relates to a multi-part valve assembly of various materials constructed in a novel manner that replaces conventional two and three part welded valves. 
       BACKGROUND OF THE INVENTION 
       [0003]    Valves have been the subject of engineering design efforts for many years, and millions of them have been used. The engineering development of valves has stagnated in this crowded and mature field of technology. Improvements have been elusive in recent years, even as the cost of materials and manufacturing has continued to climb. 
         [0004]    The basic valve structure is present in several U.S. patent publications. Some of these describe conventional methods of building a valve, and others describe methods that have been rejected by industry. Fewer disclosures teach multiple component valves, as valves having multiple components have heretofore been disfavored for a number of reasons. Primarily, they are viewed as more costly to manufacture. Multiple components require multiple manufacturing steps, assembly steps, and fit-tolerances requirements that valves having fewer parts do not have. Secondly, each assembly and connection is deemed a potential failure point, so these valves are again, disfavored. 
         [0005]    Fracking valves are a particular valve used to pump hard material into a production wellbore for the purpose of fracturing the reservoir containing formations to increase fluid flow into the wellbore. Such pumps are reciprocating, positive displacement pumps in which the valves are held closed by springs and open and close by differential pressure. The pumps deliver clear fluids or slurries through simple poppet valves that are activated (opened and closed) by the fluid pressure differential generated when the mechanical energy of the pump is converted into fluid pressure. 
         [0006]    In oil and gas exploration, there are two common reciprocating, positive displacement applications; mud pumps and well service pumps. This invention is also appropriate in both of these categories as well as other, general industrial reciprocating, positive displacement applications. Pump valves in these applications must be guided as they move back and forth about an axis parallel to the fluid flow. The guides may be “stems” or “wings” and these may be on either side or both sides of the valve. They must remain an inseparable part of the pump valve during its useful life. 
         [0007]    Due to the hardness of the material being pumped, valves include a soft seating material, such as a urethane insert, such that a seal can be obtained that would be prevented with a metal-to-metal valve seating. The softer insert component necessitates at least some assembly in frack valves. Other than the inclusion of the insert, conventional manufacturing practice has been to minimize the number of components in a valve assembly. 
         [0008]    Conventional pump valves are thus made from a pair of near net shape pieces of low carbon alloy steel that are welded together and then carburized to produce a hard, wear resistant surface. The process of manufacturing such near net shapes is expensive. Alternatively, pump valves are made from high carbon, low alloy steels of one expensive piece that requires detailed finishing, as these alloys are generally not welded. 
         [0009]    One form of convention valve manufacturing includes making the components of the valve of high alloy steel such as 8620 or 4130. These are expensive grades of steel for manufacturing a limited life product. Additionally, conventional manufacturing techniques generate waste. 
         [0010]    Conventional valve guides are manufactured by investment casting. It is common practice to forge a one-piece valve and top stem of low carbon alloy steel. The two pieces are welded together and carburized as a single piece. 
         [0011]    An alternative known method of making valves is to make a single investment casting of the entire valve for assembly with only the insert. As with the other method, the entire part is then carburized to harden it. 
         [0012]    An alternative known method of making valves is to make a single piece forging from a high carbon alloy steel. Areas that require hardened surfaces are induction or flame hardened. However, the only areas of the valve that require hardened surfaces are relatively small and include the face of the valve and the outer edges of the guides. 
         [0013]    The present invention replaces expensive raw material forms with a combination of inexpensive pieces and allows the most productive selective hardening processes to be used. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention provides a method of manufacturing and assembling a pump valve that allows the use of materials usually considered unsuitable for multiple components welded together to be constructed as a weldment. 
         [0015]    This present invention provides for the use of high carbon or high carbon alloy steel that can be induction or flame hardened and a collection of inexpensive pieces to be assembled and captured as a finished unit at the time of welding. The weld can be a solid state inertia or friction weld or any appropriate melt fusion technique. The assembly includes a retaining pin, a guide, a valve, an insert, a retainer, and a retainer cap. The retainer cap is welded to an end of the retaining pin to compress the other elements into an assembly. 
         [0016]    One embodiment of the present invention provides for the assembly of several components of simpler geometry that would not generally be considered candidates for welding because of their composition. 
         [0017]    In another embodiment, a valve assembly is provided comprising a retaining pin, a wing guide located on the retaining pin, and a valve located on the retaining pin above the guide. An insert is located on the valve. An insert retainer is located on the retaining pin above the insert. A retainer cap is welded to the retaining pin to hold the collective assembly together. 
         [0018]    In another embodiment, the top stem, retainer, wing guide stem, and wing guide are comprised of a low carbon, or low alloy steel material, and the valve is comprised of a steel that is higher in carbon content than that of the retaining pin, guide, retainer, and retainer cap. 
         [0019]    In another embodiment, the weld between the retainer cap and the retaining pin is an inertia weld. 
         [0020]    In another embodiment, the retainer cap has a nonagon configuration. 
         [0021]    In another embodiment, the guide has a top portion and three legs extending downward from the top portion. A footer extends outward from each leg. Three stabilizers extend downward from the top portion, one each between the downwardly extending legs. 
         [0022]    In another embodiment, a plurality of tabs extends outward from the top portion. The tabs engage the internal circumference of a circular recess in the valve to center the guide concentrically with the valve. 
         [0023]    In another embodiment, the retaining pin has a generally triangular head for fitted engagement with the underside of the guide. 
         [0024]    A primary advantage of the present invention is that many of the parts may be made of material that is easy to machine, such that these components can be made less expensively. 
         [0025]    Another advantage of the present invention is that many of the components need not be heat treated, eliminating a costly process step that is applied to the entirety of conventional valve assemblies. 
         [0026]    Another advantage of the present invention is that it is unnecessary to selectively and manually apply and remove expensive compounds needed to prevent carburization of several surfaces to which hardening is undesirable. 
         [0027]    The advantages and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIG. 1  is an isometric view of the valve assembly shown in accordance with certain embodiments of the present invention, as viewed from the top of the valve. 
           [0029]      FIG. 2  is an isometric view of the valve assembly of  FIG. 1  as viewed from the bottom of the valve. 
           [0030]      FIG. 3  is an isometric exploded view of the valve assembly of  FIGS. 1-2  shown in accordance with certain embodiments of the present invention. 
           [0031]      FIG. 4  is a bottom view of the valve assembly embodiment of  FIGS. 1-3 , illustrating a section line A-A through this view of the valve assembly. 
           [0032]      FIG. 5  is a sectional view of the valve assembly embodiment of  FIGS. 1-4  sectioned at A-A as illustrated in  FIG. 4 . 
           [0033]      FIG. 6  is an isometric view of the retaining pin component of the valve assembly embodiment illustrated in  FIGS. 1-3 . 
           [0034]      FIG. 7  is a bottom view of an in-process guide component of the valve assembly embodiment illustrated in  FIGS. 1-3 . 
           [0035]      FIG. 8  is a bottom view of the guide component of  FIG. 7  after a forming step. 
           [0036]      FIG. 9  is an isometric view of the guide component of  FIG. 8 . 
           [0037]      FIG. 10  is a cross-sectional side view of the valve component of the valve assembly embodiment illustrated in  FIGS. 1-3 . 
           [0038]      FIG. 11  is a cross-sectional side view of the insert component of the valve assembly embodiment illustrated in  FIGS. 1-3 . 
           [0039]      FIG. 12  is a cross-sectional side view of the retainer component of the valve assembly embodiment illustrated in  FIGS. 1-3 . 
           [0040]      FIG. 13  is a bottom view of the retainer cap of the valve assembly embodiment illustrated in  FIGS. 1-3 . 
           [0041]      FIG. 14  is a sectional view of the retainer cap of the valve assembly embodiment illustrated in  FIGS. 1-3  sectioned at B-B as illustrated in  FIG. 13 . 
       
    
    
       [0042]    The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0043]    The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. 
         [0044]      FIG. 1  is an isometric view of an embodiment of a valve assembly  10  of the present invention as viewed generally from the top of valve assembly  10 .  FIG. 2  is an isometric view of this embodiment of valve assembly  10  as viewed generally from the bottom of valve assembly  10 . 
         [0045]      FIG. 3  is an isometric exploded view of an embodiment of valve assembly  10 , illustrating the multiple components of this embodiment. Valve assembly  10  comprises a retaining pin  20 . A guide  30  is positioned on retaining pin  20 . A valve  50  is positioned on retaining pin  20  above guide  30 . An insert  60  is positioned on and in engagement with valve  50 . A retainer  70  is positioned on retaining pin  20  above and engaging insert  60  and valve  50 . A retainer cap  80  is welded to retaining pin  20  and optionally to retainer  70 . 
         [0046]      FIG. 4  is a bottom view of the embodiment of valve assembly  10  illustrated in  FIGS. 1-3 , and providing a section line A-A through this view of valve assembly  10 . 
         [0047]      FIG. 5  is a sectional view of the valve assembly embodiment of  FIGS. 1-4  sectioned at A-A as illustrated in  FIG. 4 . Valve assembly  10  is illustrated inside a cylinder  100 . As shown, guide  30  centers valve assembly  10  inside cylinder  100 . Valve  50  engages cylinder  100  in normal operation, as does insert  60 . Retainer  70  compresses insert  60 , valve  50 , and guide  30  between retaining pin  20  and retainer cap  80 . Retainer cap  80  is welded at  90  to retaining pin  20  to form a secure valve assembly  10  in which the component parts do not rotate relative to each other. In an optional embodiment illustrated, retainer cap  80  is also welded at  92  to retainer  70 . In a preferred embodiment, retainer cap  80  is friction, or inertia welded at  90  to retainer pin  20  and/or friction or inertia welded at  92  to retainer  70 . 
         [0048]      FIG. 6  is an isometric view of an embodiment of the retaining pin  20  component of the illustrated embodiment of valve assembly  10 . In the embodiment illustrated, retaining pin  20  has a triangular shaped base  22 . Referring back to  FIG. 4 , it is seen that a substantially triangular head  22  of retaining pin  20  provides an increased contact surface area to better secure the generally triangular configuration of guide  30  into valve assembly  10 . 
         [0049]    A pin shaft  24  extends upwards from the center of base  22 . An end face  26  is formed on the end of pin shaft  24  opposite to base  22 . In the disclosed assembly, retaining pin  20  may be made of low carbon steel, such as  1018  or other suitable material. In this embodiment, heat treatment of retaining pin  20  is advantageously not required. 
         [0050]      FIG. 7  is a bottom view of an embodiment of guide  30  of valve assembly  10 , shown in process. Among the several unique features of the present invention is the inclusion of a flat stock guide component  30 , shown here after stamping and prior to forming. Optionally, guide  30  may be formed by laser cutting. Guide  30  has an aperture  32  for positioning guide  30  over retaining pin  20 . At this stage, guide  30  has a substantially flat central portion  40 . 
         [0051]    Referring to  FIG. 7 , dashed lines A, B and C, illustrate nine separate folds of the flat stock of guide  30  that are required to create the final part illustrated in this embodiment. Folds ‘A’ create three footers  38 . Folds ‘B’ create three legs  36 , which include footers  38 . Folds ‘C’ create three stabilizers  34 . Of these components, only footers  38  may come into contact with cylinder  100  ( FIG. 4 ). Footers  38  may have hardfacing or other treatment applied to enhance their wear resistance without the need to heat treat the entire valve assembly. 
         [0052]      FIG. 8  is a bottom view of guide  30  of  FIG. 7  after a forming step which includes the bending of folds A, B and C.  FIG. 9  is an isometric view of the embodiment of guide  30  illustrated in  FIG. 8 . As best seen in  FIG. 9 , folds A have created footers  38  which extend substantially perpendicular, one each, in relation to legs  36 . Folds B have created legs  36  which extend downward and substantially perpendicular in relation to top surface  34 . Folds C have created stabilizers  34 , which also extend downward and substantially perpendicular in relation to top surface  40 . 
         [0053]    In a preferred embodiment illustrated in  FIGS. 8 and 9 , the folds at B and C can be advantageously formed such that contiguous stabilizers  34  and legs  36  provide a singular substantially continuous structure. In this manner, stabilizers  34  and legs  36  provide mutual support and strengthen the structure of guide  30 . 
         [0054]    As best seen in  FIGS. 7 and 9 , a plurality of tabs  42  is provided that extends outward from central portion  40 . Tabs  42  may be used to provide locating structures for accurate bending of folds A, B, and C. Referring back to  FIG. 4 , tabs  42  further provide triangulated positioning of guide  30  inside a recess  57  (see  FIG. 10 ) of valve  50  of valve assembly  10 . In this manner, a more accurate concentric alignment of the guide  30  and footers  38  can be achieved with regard to the center of valve  50 . It is understood that such concentricity between these structures is critical to the life and performance of valve assembly  10 . It is further understood that direct three-point alignment between valve  50  and guide  30  is superior to the inevitable accumulated tolerances realized in aligning all components on a third body, such as retaining pin  20 . 
         [0055]    As described, the unique configuration and process for manufacturing guide  30  may be advantageously made of an inexpensive low carbon, or low carbon alloy sheet steel, or other affordable material. Guide  30  may also be made of high carbon steel. It may only be necessary to heat treat or otherwise surface treat legs  36  of guide  30 . Legs  36  and/or guide  30  may be readily heat treated by various means, including, but not limited to, induction or laser heat treating, spot welding, or conventional hardfacing. 
         [0056]      FIG. 10  is a cross-sectional side view of an embodiment of valve  50  of valve assembly  10 . In this embodiment, valve  50  has an aperture  52  for location of valve  50  onto retaining pin  20 . Valve  50  has a recess  57  on bottom surface  54  and an opposite top surface  55  connected at their centers by aperture  52 . Valve  50  has a valve face  56 . A tongue and groove  58  is provided between valve face  56  and top surface  55 . Recess  57  of bottom surface  54  engages central portion  40  of guide  30  when assembled on retaining pin  20 . Tabs  42  of guide  30  position guide  30  centrally by engaging the inner circumference of recessed surface  54 . 
         [0057]    Valve face  56  is commonly angled between 30 and 45 degrees relative to recessed bottom surface  54 . Valve  50  may be made of suitable steel such as  4150  or other relatively hard steel. In one embodiment, valve  50  may be hardened by induction hardening or other appropriate heat treating method. Advantageously, valve  50  may be heat treated without the requirement to heat treat the entire valve assembly  10 . 
         [0058]      FIG. 11  is a cross-sectional side view of an embodiment of insert  60  of valve assembly  10 . Insert  60  has an aperture  62 . Insert  60  has a top surface  68  and a face  66 . A tongue and groove  64  is provided between aperture  62  and face  66 . Tongue and groove  64  is configured for complementary engagement with tongue and groove  58  of valve  50 . Aperture  62  fits over valve  50  to engage insert  60  with valve  50 . 
         [0059]    Insert face  66  is commonly angled between  30  and  45  degrees relative to insert top surface  68 , such that when insert  60  is located onto valve  50 , insert face  66  and valve face  56  form a semi-continuous surface for engaging cylinder  100 , as best seen in  FIG. 5 . 
         [0060]    Insert  60  may be made of urethane or other suitable material that is used to manufacture inserts for conventional valve designs. Insert  60  operates to provide a seal with cylinder  100  when debris common to operations such as fracking prevents a metal-to-metal seal. In a preferred embodiment, insert  60  is compressively fit over valve  50 , thereby enhancing the wear performance of the elastomeric insert  60 . 
         [0061]      FIG. 12  is a cross-sectional side view of an embodiment of retainer  70  of valve assembly  10 . Retainer  70  has an aperture  72  for location onto retaining pin  20 . Retainer  70  has a bottom surface  74  and a top surface  76 . Bottom surface  74  engages top surface  62  of insert  60  when assembled on retaining pin  20 . Retainer  70  may be advantageously made of low carbon steel such as  1020  steel or other suitable material. In the embodiment illustrated, heat treatment is optional, and not required. 
         [0062]    In the embodiment illustrated, a first circular recess  78  is located in top surface  76 . In an optional embodiment, a second circular recess  79  is located on top surface  76 . 
         [0063]      FIG. 13  is a bottom view of an embodiment of retainer cap  80  of the valve assembly  10  embodiment illustrated in  FIGS. 1-3 .  FIG. 14  is a sectional view of the embodiment of retainer cap  80  sectioned at B-B as illustrated in  FIG. 13 . Referring to  FIGS. 13 and 14 , retainer cap  80  has a head portion  82  on top of a stem portion  84 . A substantially flat base  86  is located at the end of stem  84 . A flash trap  88  is formed on the underside of head portion  82 , adjacent stem  84 , to facilitate welding. 
         [0064]    In the embodiment illustrated, as best seen in  FIG. 13 , the exterior of head portion  82  is configured to have nine symmetrical sides. The nonagon exterior perimeter generates contiguous sides having an angle ‘A’ of about 40 degrees between them. Other shapes may be used. Retainer cap  80  may be made of a low alloy, or low carbon steel. Heat treatment of retainer cap  80  is optional, and is not required. 
         [0065]    In the assembly of valve assembly  10 , guide  30 , valve  50 , insert  60 , and retainer  70  are stacked on stem  24  of retaining pin  20 . Force is applied between head  22  and retainer cap  80  to compress the assembly. Base  86  of retainer cap  80  is welded to end face  26  of retaining pin  20 . This weld can be a solid state inertia or friction weld or any appropriate meld fusion technique. In another embodiment illustrated, cap  80  may optionally be welded directly to retainer  70  on top surface  76  between first recess  78  and second recess  79 . 
         [0066]    Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Technology Classification (CPC): 5