Abstract:
An apparatus according to which a power end of a reciprocating pump assembly includes a block having bores formed therethrough, and crossheads disposed in the bores and adapted to reciprocate therein. A lubrication pump is in fluid communication with the bores. The pump is operable to pump lubrication fluid into each of the bores so that the crossheads are lubricated as they reciprocate within their respective bores. In another aspect, a power end includes a crosshead block and a power frame connected thereto, the frame including rib plates and supporting the crosshead block. In yet another aspect, a method includes casting a crosshead block; fabricating rib plates; connecting the rib plates to form a frame; and connecting the cast crosshead block to the frame. In some embodiments, the power ends may be used in oilfield operations such as, for example, the cementing, acidizing, or fracturing of a subterranean wellbore.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of the filing date of, and priority to, U.S. Application No. 62/353,824, filed Jun. 23, 2016, the entire disclosure of which is hereby incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates generally to a reciprocating pump and, more specifically, to enhancing the performance, reliability, and/or capacity of the reciprocating pump by equipping the reciprocating pump with an improved power frame having an external, self-contained, integrated lubrication system. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    Various pumps are used in connection with oilfield operations such as, for example, the cementing, acidizing, or fracturing of a subterranean wellbore. During such operations, these pumps are often subject to short and frequent duty cycles, and are required to deliver a fluid or slurry to the wellbore at pressures up to 20,000 psi. An example pump for oilfield operations is a reciprocating pump. The reciprocating pump may include a fluid end and a power end operably coupled thereto. The fluid end includes a number of pressure chambers that are in fluid communication with a suction manifold and a discharge manifold. The fluid end further includes plungers that are received by, and extend within, the respective pressure chambers. The power end includes a motor connected to a crank shaft. The crankshaft is coupled to respective ones of the plungers via a connecting rod, a crosshead, and a pony rod. The crossheads are disposed within crosshead bores, within which the crossheads are adapted to reciprocate. The connecting rods connect respective ones of the crossheads to the crankshaft, while the pony rods connect respective ones of the crossheads to the plungers. The motor drives the crankshaft, causing the crossheads to reciprocate within the corresponding crosshead bores and, consequently, causing the plungers to reciprocate within the corresponding pressure chambers. The power end includes a power frame that is adapted to support various components of the reciprocating pump such as, for example, the crankshaft and the crosshead bores. Time consuming and/or labor intensive efforts may be required to manufacture the power frame and the crosshead bores. Further, the performance of the reciprocating pump may be impaired by inefficient and/or unreliable delivery of lubrication fluid to the crosshead bores. Consequently, the crossheads are inadequately lubricated as they reciprocate within the crosshead bores. Therefore, what is needed is an apparatus or method that addresses one or more of the foregoing issues, and/or other issue(s). 
       SUMMARY 
       [0004]    In a first aspect, the present disclosure introduces an apparatus that includes a power end of a reciprocating pump assembly, the power end including a block including a plurality of bores formed therethrough; and a plurality of crossheads disposed in the plurality of bores, respectively, and adapted to reciprocate therein; a skid on which the power end is mounted; a tank mounted on the skid and in fluid communication with each of the bores; and a pump in fluid communication with the tank and each of the bores; wherein the pump is operable to pump lubrication fluid from the tank and into each of the bores so that the crossheads are lubricated as they reciprocate within their respective bores. 
         [0005]    In an embodiment, the skid is adapted to be mounted and/or transported on a trailer, but the tank and the pump are separate from, or independent of, the trailer so that the operation of the pump, namely to pump the lubrication fluid from the tank and into each of the bores so that the crossheads are lubricated as they reciprocate within their respective bores, is not dependent upon any pump lubrication feature of the trailer. 
         [0006]    In an embodiment, the tank and the pump are external to the power end so that each of the tank and the pump is serviceable or replaceable without any interference to the power end. 
         [0007]    In an embodiment, the crosshead block further includes a plurality of lubrication ports in fluid communication with the plurality of bores, respectively; and wherein the apparatus further includes a manifold connected to the power end, the manifold defining a fluid chamber in fluid communication with the pump, and also in fluid communication with the plurality of bores via at least the plurality of lubrication ports, respectively. 
         [0008]    In an embodiment, the crosshead block further includes a plurality of drain ports in fluid communication with the plurality of bores, respectively; and wherein each of the drain ports is in fluid communication with the tank to permit the lubrication fluid to drain back into the tank. 
         [0009]    In an embodiment, the apparatus includes a fluid return line via which the lubrication fluid drains back from the drain ports and into the tank, the lubrication fluid including a filter that is positioned external to the power end so that the filter is serviceable or replaceable without any interference to the power end. 
         [0010]    In an embodiment, the skid includes a base member and a platform member spaced therefrom; and a region defined between the base member and the platform member spaced therefrom; wherein the power end is mounted on the platform member; and wherein the tank and the pump are disposed in the region. 
         [0011]    In an embodiment, the apparatus includes the reciprocating pump assembly, which is mounted on the skid, the reciprocating pump assembly including the power end and a fluid end operably coupled thereto. 
         [0012]    In an embodiment, the power end further includes a power frame to which the block is connected, the power frame including a plurality of parallel-spaced rib plates, each of the rib plates including a brace portion, each of the brace portions defining a contact surface; wherein the respective contact surfaces of the brace portions are coplanar; and wherein the block engages the coplanar contact surfaces. 
         [0013]    In a second aspect, the present disclosure introduces an apparatus that includes a power end of a reciprocating pump assembly, the power end including a crosshead block including a plurality of bores formed therethrough; and a power frame connected to the crosshead block, the power frame including a plurality of rib plates spaced in a parallel relation and supporting the crosshead block. 
         [0014]    In an embodiment, the crosshead block is cast to reduce weld joints in the power end, and wherein each of the rib plates is not cast but instead is fabricated. 
         [0015]    In an embodiment, the power end includes a power housing connected to the power frame; a hollow pinion shaft, at least a portion of which is housed within the power housing; and first and second gear covers connected to respective opposing sides of the power housing; wherein each of the first and second gear covers is either stamped or hydroformed. 
         [0016]    In an embodiment, each of the rib plates includes a plurality of openings formed therethrough; wherein the respective pluralities of openings are aligned with each other; wherein the power frame further includes a plurality of support rods, each of which is connected to each of the rib plates; and wherein each of the support rods extends through corresponding ones of the aligned openings formed through the rib plates. 
         [0017]    In an embodiment, the power end includes a crankshaft that extends through the plurality of rib plates and is adapted to rotate; wherein each of the rib plates includes a central opening, which defines, or is part of, a rotational bearing that is adapted support the crankshaft as it rotates. 
         [0018]    In an embodiment, each of the rib plates includes a brace portion, the brace portion defining a contact surface; wherein the respective contact surfaces of the brace portions are coplanar; and wherein the crosshead block engages the coplanar contact surfaces. 
         [0019]    In an embodiment, the apparatus includes a skid on which the power end is mounted; a fluid end mounted on the skid and operably coupled to the power end; a tank mounted on the skid and in fluid communication with each of the bores of the crosshead block; and a pump mounted on the skid and in fluid communication with the tank and each of the bores of the crosshead block; wherein the pump is operable to pump lubrication fluid from the tank and into each of the bores of the crosshead block. 
         [0020]    In a third aspect, the present disclosure introduces a method that includes casting a crosshead block of a power end of a reciprocating pump assembly; fabricating a plurality of rib plates; connecting the rib plates together to form a power frame; and connecting the cast crosshead block to the power frame. 
         [0021]    In an embodiment, the method includes connecting a power housing to the power frame; and housing at least a portion of a hollow pinion shaft within the power housing. 
         [0022]    In an embodiment, the method includes forming first and second gear covers, wherein each of the first and second gear covers is formed by either stamping or hydroforming; attaching the first and second gear covers to respective opposing sides of the power housing; and operably coupling a fluid end to the power end to form the reciprocating pump assembly. 
         [0023]    In an embodiment, the method includes mounting the power end on a skid; and mounting a tank and a pump on the skid; wherein the tank is in fluid communication with the crosshead block; wherein the pump is in fluid communication with the tank and the crosshead block; and wherein the pump is operable to pump lubrication fluid from the tank and into the crosshead block. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Various embodiments of the present disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure. In the drawings, like reference numbers may indicate identical or functionally similar elements. 
           [0025]      FIG. 1  is a sectional side view of a reciprocating pump assembly, the reciprocating pump assembly including a fluid end and a power end, according to an embodiment. 
           [0026]      FIG. 2  is a diagrammatic top view of the reciprocating pump assembly of  FIG. 1 , according to an embodiment. 
           [0027]      FIG. 2A  is a diagrammatic side view of a rib plate of the power end of the reciprocating pump assembly of  FIG. 2 , according to an embodiment. 
           [0028]      FIG. 3  is a diagrammatic front view of the power end of  FIGS. 1 and 2 , according to an embodiment. 
           [0029]      FIG. 3A  is a flow chart illustration of a method of manufacturing the power end of  FIGS. 1-3 , according to an embodiment. 
           [0030]      FIG. 4  is a diagrammatic side view of an apparatus that includes a reciprocating pump assembly, including a power end and a fluid end, the reciprocating pump assembly being mounted on a skid, the power end including an integrated lubrication system that includes a tank, a pump, and a manifold, according to an embodiment. 
           [0031]      FIG. 5  is a diagrammatic front view of the power end of  FIG. 4 , the power end being disposed on the skid of  FIG. 4  and including the integrated lubrication system, according to an embodiment. 
           [0032]      FIG. 6  is a diagrammatic top view of the apparatus of  FIG. 4 , including the reciprocating pump assembly of  FIGS. 1 and 2  being disposed on the skid of  FIGS. 4 and 5 , the power end including the integrated lubrication system, according to an embodiment. 
           [0033]      FIG. 7  is a diagrammatic illustration of the apparatus of  FIG. 4 , including the integrated lubrication system, according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    Referring to  FIG. 1 , a reciprocating pump assembly is schematically illustrated and generally designated by the reference numeral  10 . The reciprocating pump assembly  10  includes a fluid end  12  and a power end  14  operably coupled thereto. The fluid end  12  of the reciprocating pump assembly  10  includes one or more cylinders  16 , each of which includes a pressure chamber  18 . In one embodiment, the reciprocating pump assembly  10  is a quintuplex pump, with the fluid end  12  including five of the cylinders  16 . In other embodiments, the reciprocating pump assembly  10  may include any number of the cylinders  16  such as, for example, one cylinder, two cylinders (duplex pump), three cylinders (triplex pump), four cylinders (quadriplex pump), or more. The cylinders  16  and their respective pressure chambers  18  are spaced laterally across the fluid end  12 . The pressure chambers  18  are each in fluid communication with a suction manifold  20  and a discharge manifold  22 . The fluid end  12  further includes plungers  24  that are received by, and extend within, the respective pressure chambers  18 . Each plunger  24  is adapted to reciprocate within the corresponding pressure chamber  18  during operation of the reciprocating pump assembly  10 . 
         [0035]    The power end  14  of the reciprocating pump assembly  10  includes a crankshaft  26  that includes one or more crank throws  26   a , corresponding to the one or more cylinders  16  of the fluid end  12 , and a main shaft  26   b . The crank throws  26   a  are connected to the main shaft  26   b  and are each offset from the rotational axis of the crankshaft  26 . The crankshaft  26  is mechanically coupled to a motor (not shown) via a bull gear  28  and a pinion  30 . The bull gear  28  is attached to the crankshaft  26  and the pinion  30  is connected to the motor (not shown). The gear teeth of the bull gear  28  mesh with the gear teeth of the pinion  30 , thereby transmitting torque therebetween. The crank throws  26   a  are each coupled to a respective one of the plungers  24  via a mechanical linkage  32 , each of which includes a connecting rod  34 , a crosshead  36 , and a pony rod  38 . Each of the crossheads  36  is disposed within a corresponding crosshead bore  40 , within which the crosshead  36  is adapted to reciprocate. The connecting rods  34  connect respective ones of the crossheads  36  to respective ones of the crank throws  26   a . Further, the pony rods  38  connect respective ones of the crossheads  36  to respective ones of the plungers  24 . 
         [0036]    In some embodiments, in operation, the motor (not shown) rotates the pinion  30 , which, as a result, rotates the bull gear  28  and the crankshaft  26 . The crankshaft  26  rotates the crank throws  26   a  about the central axis of the main shaft  26   b . The crank throws  26   a , in turn, are operable to drive the mechanical linkages  32 , including respective ones of the connecting rods  34 , the crossheads  36 , and the pony rods  38 , causing the crossheads  36  to reciprocate within the corresponding crosshead bores  40 . The reciprocating motion of the crossheads  36  is transferred to respective ones of the plungers  24  via the pony rods  38 , causing the plungers  24  to reciprocate within the corresponding pressure chambers  18 . As the plungers  24  reciprocate within the respective pressure chambers  18 , fluid is drawn into the pressure chambers  18  from the suction manifold  20  and, thereafter, discharged from the pressure chambers  18  into the discharge manifold  22 . 
         [0037]    Referring to  FIGS. 2, 2A, and 3  with continuing reference to  FIG. 1 , the power end  14  of the reciprocating pump assembly  10  includes a power frame  42  and a crosshead block  44 , which is connected to, and supported by, the power frame  42 . The power frame  42  includes a plurality of parallel-spaced rib plates  42   a  and a plurality of support rods  42   b . The rib plates  42   a  are spaced laterally across the power end  14  and are connected to one another by the support rods  42   b , which extend between adjacent ones of the rib plates  42   a . As shown most clearly in  FIG. 2A , a plurality of openings  43  are formed through each of the rib plates  42   a . The openings  43  formed through successive ones of the rib plates  42   a  are substantially aligned with one another and are adapted to accommodate respective ones of the support rods  42   b . Accordingly, the support rods  42   b  extend laterally across the power end  14  and through corresponding ones of the aligned openings  43 , extending through the rib plates  42   a  and connecting the rib plates  42   a  to one another. The support rods  42   b  may be connected to the rib plates  42   a  by using any one of a number of fabrication processes such as, for example, welding, brazing, soldering, another fabrication process, and/or any combination thereof. Additionally, in some embodiments, one or more of the support rods  42   b  may be a threaded rod, which is connected to respective ones of the rib plates  42   a  by threadably engaging a pair of fasteners (e.g., nuts, bushings, fittings, etc.) with the support rod  42   b  and tightening the fasteners against opposing sides of the rib plate  42   a.    
         [0038]    As shown in  FIGS. 2, 2A, and 3 , in some embodiments, the power end  14  may include nine support rods  42   b , with each rib plate  42  including nine corresponding openings  43 . In other embodiments, the power end  14  may include four, six, or another quantity of the support rods  42   b.    
         [0039]    The power frame  42  supports the crankshaft  26 , the bull gear  28 , and the pinion  30  during the operation of the reciprocating pump assembly  10 . In one embodiment, as shown in  FIG. 2A , each of the rib plates  42   a  includes a central opening  43   a , which may support a respective portion of the crankshaft  26 . Specifically, the central openings  43   a , which are formed through successive ones of the rib plates  42   a , may define, or be a part of, rotational bearings  43   b , which support respective portions of the main shaft  26   b , while the crank throws  26   a  are disposed laterally between the rib plates  42   a . Further, the bull gear  28 , which meshes with the pinion  30 , is connected to an end portion of the main shaft  26   b . The pinion  30 , in turn, is connected to the motor (not shown). In some embodiments, the reciprocating pump assembly  10  includes two of the bull gears  28  (as shown in  FIGS. 2 and 3 ), which are attached to opposing end portions of the main shaft  26   b . As a result, the reciprocating pump assembly  10  also includes two pinions  30 , which mesh with the respective bull gears  28  and are connected via a pinion shaft  31 . The pinion shaft  31  is supported by the power frame  42  and extends laterally across the power end  14  between the pinions  30 , thereby transferring torque between the pinions  30  and enabling the pinions  30  to mesh with the respective bull gears  28 . In an embodiment, the pinion shaft  31  is hollow in order to reduce the overall mass of the reciprocating pump assembly  10 . 
         [0040]    In some embodiments, the crosshead block  44  is manufactured by casting, forming, and/or machining a solitary integral mass. During the manufacturing process, the crosshead bores  40  are formed through the crosshead block  44 . As a result, the crosshead bores  40  are distributed across the crosshead block  44 , which extends laterally across the power end  14  and is connected to, and supported by, the power frame  42 . Specifically, the rib plates  42   a  each include a brace portion  46  that supports at least a portion of the crosshead block  44 . The brace portions  46  each include a contact surface  48 , which engages the crosshead block  44 . In an embodiment, the contact surfaces  48  of the respective rib plates  42   a  are coplanar and thus substantially aligned with one another, thus defining a plane  49  upon which the crosshead block  44  is disposed. The crosshead block  44  is engaged with the contact surfaces  48 , and is connected to the brace portions  46  at the contact surfaces  48 . As a result, the brace portions  46  of the rib plates  42   a  support the crosshead block  44  in a fixed position relative to the crankshaft  26 . Consequently, respective ones of the crosshead bores  40  are maintained in fixed positions that are substantially aligned with respective ones of the crank throws  26   a.    
         [0041]    With continuing reference to  FIGS. 2, 2A, and 3 , the reciprocating pump assembly  10  includes a power end housing  50  and a pair of gear covers  52 . The power end housing  50  is made of a sheet material that extends about, and is connected to, the outer periphery of the power frame  42 , thereby enclosing the power frame  42  and respective portions of the crankshaft  26 , the pinion shaft  31 , the mechanical linkages  32 , and the crosshead block  44 . The gear covers  52  are attached to respective opposing sides of the power end housing  50 , thereby enclosing respective ones of the bull gears  28  and the pinions  30 , including the respective end portions of the crankshaft  26  and the pinion shaft  31 . In an embodiment, the gear covers  52  are formed by folding and welding a section of sheet material. In some embodiments, the gear covers  52  are formed by another manufacturing process such as, for example, hydroforming, stamping, casting, forming, machining, another manufacturing process, or any combination thereof. In some embodiments, the gear covers  52  are formed by stamping. In some embodiments, the gear covers  52  are formed by hydroforming. In some embodiments, the gear covers  52  are formed by either stamping or hydroforming. 
         [0042]    Referring to  FIG. 3A  with continuing reference to  FIGS. 1, 2, 2A, and 3 , a method of manufacturing the power end  14  is generally referred to by the reference numeral  53  and includes a step  53   a , at which the crosshead block  44  is cast. At step  53   b , each of the rib plates  42   a  is not cast but instead is fabricated by, for example, cutting, assembling, welding, bending, etc. one or more metal pieces to fabricate the rib plates  42   a  and/or respective portions thereof. At step  53   c , the rib plates  42   a  are connected together using the support rods  42   b  to form the power frame  42 , in accordance with the foregoing. At step  53   d , the crosshead block  44  is connected to the power frame  42 , in accordance with the foregoing. At step  53   e , the power housing  50  is connected to the power frame  42 . At step  53   f , the pinion shaft  31  is a hollow pinion shaft, and at least a portion of the pinion shaft  31  is housed within the power housing  50 . At step  53   g , the gear covers  52  are formed by either stamping or hydroforming. At step  53   h , the gear covers  52  are attached to opposing sides of the power housing  50 . 
         [0043]    In some embodiments, casting the crosshead block  44  at the step  53   a  reduces the quantity of weld joints in the power end  14 ; since in many cases structural failures occur at weld joints, reducing the number of weld joints, by casting the crosshead block  44 , reduces the risk of structural failure in the power end  14 . In some embodiments, the step  53   f  reduces the overall mass or weight of the power end  14 . In some embodiments, the step  53   g  reduces the weight of the power end  14 , and also reduces the cost of the power end  14  with respect to material costs and labor costs; since at the step  53   g  the gear covers  52  are either stamped or hydroformed, the costs associated with manufacturing processes such as folding, bending, and welding metal for the covers  52  are either eliminated or significantly reduced. 
         [0044]    In an embodiment, as illustrated in  FIGS. 4-6  with continuing reference to  FIGS. 1-3 , an apparatus is generally referred to by the reference numeral  53   i . The apparatus  53   i  includes a reciprocating pump assembly  53   j , which is similar to the reciprocating pump assembly  10  and includes components that are identical, or substantially similar, to the components of the reciprocating pump assembly  10 ; these identical or substantially similar components will be given the same reference numerals. 
         [0045]    As shown in  FIGS. 4-6 , the reciprocating pump assembly  53   j  further includes an external, self-contained, and integrated lubrication system  54 , which is adapted to deliver a lubrication fluid to respective ones of the crosshead bores  40 , thereby lubricating the crossheads  36  as they reciprocate within the crosshead block  44 . Accordingly, a plurality of lubrication ports  56   a  are formed through the top of the crosshead block  44  and into respective ones of the crosshead bores  40 . Further, a corresponding plurality of drain ports  56   b  are formed through the bottom of the crosshead block  44  and into respective ones of the crosshead bores  40 . The lubrication system  54  includes a manifold  58 , a tank  60 , and a pump  62 , each of which is external to the power end  14 . The manifold  58  is a generally tubular vessel including opposing end caps  58   a  and  58   b , and defining a fluid chamber  58   c . The manifold  58  is disposed above the crosshead block  44  and extends across the power end  14 . The tank  60  stores the lubrication fluid for eventual circulation to the fluid chamber  58   c  of the manifold  58 . The pump  62  is in fluid communication with both the tank  60  and the manifold  58 , and is operable to pump the lubrication fluid from the tank  60  to the fluid chamber  58   c  of the manifold  58  via a fluid transfer line  63  (shown in  FIG. 7 ). The manifold  58  is connected to, and supported by, the power frame  42 . In some embodiments, the rib plates  42   a  each include a bracket (not shown) that supports at least a portion of the manifold  58 . The brackets of the respective rib plates  42   a  are substantially aligned with one another, thus supporting the manifold  58  in a fixed position relative to the crosshead block  44  and the respective crosshead bores  40 . In some embodiments, the manifold  58  is connected to, and supported by, the crosshead block  44  and/or the power frame  42 . 
         [0046]    The manifold  58  includes a plurality of lubrication ports  64 , each corresponding to, and aligned with, the respective lubrication ports  56   a  of the crosshead block  44 . A plurality of lubrication lines  66  connect the lubrication ports  64  of the manifold  58  to the respective lubrication ports  56   a  of the crosshead block  44 . As a result, the lubrication lines  66  provide fluid communication between the fluid chamber  58   c  of the manifold  58  and the respective crosshead bores  40  of the crosshead block  44 . A fluid return line  67   a  (shown in  FIG. 7 ) is connected between the drain ports  56   b , which are formed through the crosshead block  44  and into the crosshead bores  40 , and the tank  60 . The fluid return line  67   a  thus provides fluid communication between the crosshead bores  40  and the tank  60 . 
         [0047]    Referring to  FIG. 7  with continuing reference to  FIGS. 4-6 , in operation, the tank  60  is filled with the lubrication fluid. The pump  62  subsequently pumps the lubrication fluid from the tank  60  to the fluid chamber  58   c  of the manifold  58  via the fluid transfer line  63 . The lubrication fluid then passes through the lubrication ports  64  of the manifold  58 . The lubrication lines  66  transfer the lubrication fluid from the lubrication ports  64  of the manifold  58  to the lubrication ports  56   a  of the crosshead block  44 . The lubrication fluid is received by the respective crosshead bores  40  through the lubrication ports  56   a , and the lubrication fluid lubricates the crossheads  36  as they reciprocate within the crosshead block  44 . The lubrication fluid, along with any materials worn from the crossheads  36  and/or the crosshead bores  40 , passes through the drain ports  56   b  of the crosshead block  44 . The lubrication fluid then drains through the fluid return line  67   a , which includes a filter  67   b , and back into the tank  60 . In this manner, the lubrication fluid is circulated through the lubrication system  54  of the reciprocating pump assembly  53   j . The filter  67   b  collects particles contained in the lubrication fluid circulated to the tank  60  from the crosshead bores  40 ; for example, such particles may include materials worn from the crossheads  36  and/or the crosshead bores  40 . The fluid return line  67   a , the tank  60 , one or more other components of the integrated lubrication system  54 , or any combination thereof, may include one or more other filters instead of, or in addition to, the filter  67   b.    
         [0048]    As shown in  FIGS. 4-6 , the reciprocating pump assembly  53   j  and the self-contained, integrated lubrication system  54  are mounted on, and transported via, a skid  68 . The skid  68  includes a base member  68   a , a platform member  68   b , and a plurality of support members  68   c  that are connected to the base member  68   a  and the platform member  68   b . The support members  68   c  are disposed between the base member  68   a  and the platform member  68   b . The reciprocating pump assembly  53   j  is positioned on top of the platform member  68   b , which is supported from beneath by the support members  68   c . The support members  68   c  are positioned on top of the base member  68   a . A region  68   d  is thus defined between the base member  68   a , the platform member  68   b  and two or more of the support members  68   c . Although one embodiment of the skid  68  has been described above, in some embodiments the skid  68  may take the form of any raised platform upon which the reciprocating pump assembly  53   j  is supported, and beneath which a region is defined. In some embodiments, the reciprocating pump assembly  53   j  and the integrated lubrication system  54  may be positioned on top of the platform member  68   b ; in some embodiments, the skid  68  may not include one or more of the base member  68   a  and the support members  68   c.    
         [0049]    With continuing reference to  FIGS. 4-6 , the tank  60  is disposed within the region  68   d . Further, the pump  62  is disposed within the tank  60 , and is thus at least partially submerged in the lubrication fluid. In other embodiments, the tank  60  may instead be disposed within another region defined beneath the platform member  68   b  or another platform that supports the reciprocating pump assembly  53   j . In some embodiments, rather than being disposed within the tank  60 , the pump  62  may instead be disposed adjacent the tank  60 . Accordingly, the pump  62  may be disposed within the region  68   d  or within another region defined beneath the platform member  68   b  or another platform that supports the reciprocating pump assembly  53   j . In some embodiments, neither the tank  60  nor the pump  62  is disposed within the region  68   d , or within any other region defined beneath the platform member  68   b  or any other platform that supports the reciprocating pump assembly  53   j . In some embodiments, the tank  60  and the pump  62  are disposed adjacent the reciprocating pump assembly  53   j.    
         [0050]    In some embodiments, the lubrication system  54  is mounted on the skid  68  and thus the components of the lubrication system  54 , including the tank  60 , are separate from, or independent of, any trailer on which the skid  68  may be mounted and/or transported, such as a trailer  70 , which is shown in  FIG. 4  and on which the apparatus  53   i  is mounted. As a result, the operation of the lubrication system  54  is not dependent upon any pump lubrication feature of any trailer on which the skid  68  may be mounted and/or transported, such as fluid reservoirs or tanks containing lubricant or lubrication fluid, such as a tank  72 , which is shown mounted on the trailer  70  in  FIG. 4 . In some embodiments, since the reciprocating pump assembly  53   j  and the lubrication system  54  are both mounted on the skid  68 , the apparatus  53   i  may be transported by simply transporting the skid  68 . In some embodiments, since at least the tank  60  and the pump  62  are external to the power end  14 , rather than being internal to the power end  14 , at least the tank and the pump  62  may be serviced and/or replaced without any interference to the power end  14 . 
         [0051]    In some embodiments, while different steps, processes, and procedures are described as appearing as distinct acts, one or more of the steps, one or more of the processes, and/or one or more of the procedures may also be performed in different orders, simultaneously and/or sequentially. In some embodiments, the steps, processes and/or procedures may be merged into one or more steps, processes and/or procedures. 
         [0052]    In some embodiments, one or more of the operational steps in each embodiment may be omitted. Moreover, in some instances, some features of the present disclosure may be employed without a corresponding use of the other features. Moreover, one or more of the above-described embodiments and/or variations may be combined in whole or in part with any one or more of the other above-described embodiments and/or variations. 
         [0053]    In the foregoing description of certain embodiments, specific terminology has been resorted to for the sake of clarity. However, the disclosure is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes other technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as “left” and right”, “front” and “rear”, “above” and “below” and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms. 
         [0054]    In this specification, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear. 
         [0055]    Although several embodiments have been described in detail above, the embodiments described are not limiting, and those skilled in the art will readily appreciate that many other modifications, changes, and/or substitutions are possible in the embodiments without materially departing from the novel teachings and advantages of the present disclosure. Accordingly, all such modifications, changes, and/or substitutions are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, any means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Moreover, it is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6, for any limitations of any of the claims herein, except for those in which the claim expressly uses the word “means” together with an associated function.