Abstract:
According to one aspect, a pump assembly includes a fluid cylinder, and the fluid cylinder includes a fluid passage that defines a tapered internal shoulder of the fluid cylinder. The tapered internal shoulder defines a first frusto-conical surface. A valve controls flow of fluid through the fluid passage. The valve includes a valve seat, which includes a seat body disposed in the fluid passage, and a bore formed through the seat body and through which fluid flows. The seat body includes inlet and outlet end portions, wherein the fluid flows into the bore at the inlet end portion and flows out of the bore at the outlet end portion. The inlet end portion of the seat body defines a second frusto-conical surface. In one embodiment, the second frusto-conical surface engages the first frusto-conical surface to distribute and transfer loading.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of the filing date of U.S. provisional patent application No. 61/594,493, filed Feb. 3, 2012, the entire disclosure of which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates in general to pump assemblies and, in particular, a reciprocating pump assembly including a fluid cylinder and valve seats. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    Reciprocating pump assemblies typically include fluid end blocks or fluid cylinders and inlet and outlet valves disposed therein. During operation, the inlet and outlet valves typically experience high loads and frequencies. In some cases, valve seats of the inlet and outlet valves, as well as portions of the fluid cylinder engaged therewith, may be subjected to highly concentrated cyclic loads and thus may fatigue to failure. Therefore, what is needed is an apparatus or method that addresses one or more of the foregoing issues, among others. 
       SUMMARY 
       [0004]    In a first aspect, there is provided a pump assembly that includes a fluid cylinder having a first axis and a second axis perpendicular thereto. The fluid cylinder includes a first fluid passage through which fluid flows along the first axis, the first fluid passage defining a first tapered internal shoulder of the fluid cylinder, the first tapered internal shoulder defining a first frusto-conical surface, the first frusto-conical surface defining a first angle from the second axis; The pump assembly further includes a first valve to control flow of fluid through the first fluid passage. The first valve includes a first valve seat disposed in the first fluid passage. The first valve seat includes a seat body that includes an inlet end portion and an outlet end portion opposed thereto along the first axis, the inlet end portion of the seat body defining a second frusto-conical surface, the second frusto-conical surface defining a second angle from the second axis; and a bore formed through the seat body and through which fluid flows in a direction along the first axis and perpendicular to the second axis; wherein the fluid flows into the bore at the inlet end portion of the seat body and flows out of the bore at the outlet end portion of the seat body; wherein each of the first and second angles ranges from about 10 degrees to about 45 degrees measured from the second axis; and wherein the second frusto-conical surface of the inlet end portion engages the first frusto-conical surface of the fluid cylinder to distribute and transfer loading between the second and first frusto-conical surfaces. 
         [0005]    In an exemplary embodiment, the second axis intersects the seat body at an intersection, the intersection defining a first diameter of the seat body; wherein the seat body defines an axially-extending outside surface extending along the first axis from the inlet end portion to the outlet end portion, the axially-extending outside surface defining a second diameter of the seat body; wherein the second diameter of the seat body is greater than the first diameter of the seat body; and wherein the second frusto-conical surface extends between the intersection and the axially-extending outside surface. 
         [0006]    In certain exemplary embodiments, the second frusto-conical surface extends from the intersection to the outside surface in an angular direction, an axial component of which extends axially towards the outlet end portion. 
         [0007]    In another exemplary embodiment, the inlet end portion of the seat body defines an end surface that faces axially away from the outlet end portion; wherein the second axis is coplanar with the end surface; wherein the second frusto-conical surface extends from the end surface to the outside surface. 
         [0008]    In certain exemplary embodiments, the inlet end portion includes an annular portion that extends from the intersection in an axial direction away from the outlet end portion. 
         [0009]    In an exemplary embodiment, the second frusto-conical surface extends from the intersection to the outside surface in an angular direction, an axial component of which extends axially away from the outlet end portion. 
         [0010]    In another exemplary embodiment, the inlet end portion includes an annular portion that extends from the intersection in an axial direction away from the outlet end portion. 
         [0011]    In yet another exemplary embodiment, the fluid passage includes a first passage portion defining a first inside diameter of the fluid cylinder; and a second passage portion defining a second inside diameter of the fluid cylinder; wherein the second inside diameter is less than the first inside diameter; wherein the valve seat body is disposed in the second passage portion; and wherein at least a portion of the second passage portion is positioned along the first axis between the first passage portion and the first tapered internal shoulder. 
         [0012]    In a second aspect, there is provided a valve seat adapted to be disposed within a fluid cylinder of a pump assembly. The valve seat has a first axis and a second axis perpendicular thereto. The valve seat includes a seat body that includes an inlet end portion and an outlet end portion opposed thereto along the first axis, the inlet end portion of the seat body defining a frusto-conical surface, the frusto-conical surface defining an angle from the second axis; and a bore formed through the seat body and through which fluid flows in a direction along the first axis and perpendicular to the second axis; wherein the fluid flows into the bore at the inlet end portion of the seat body and flows out of the bore at the outlet end portion of the seat body; and wherein the angle ranges from about 10 degrees to about 45 degrees measured from the second axis. 
         [0013]    In certain exemplary embodiments, the second axis intersects the seat body at an intersection, the intersection defining a first diameter of the seat body; wherein the seat body defines an axially-extending outside surface extending along the first axis from the inlet end portion to the outlet end portion, the axially-extending outside surface defining a second diameter of the seat body; wherein the second diameter of the seat body is greater than the first diameter of the seat body; and wherein the frusto-conical surface extends between the intersection and the axially-extending outside surface. 
         [0014]    In an exemplary embodiment, the frusto-conical surface extends from the intersection to the outside surface in an angular direction, an axial component of which extends axially towards the outlet end portion. 
         [0015]    In another exemplary embodiment, the inlet end portion of the seat body defines an end surface that faces axially away from the outlet end portion; wherein the second axis is coplanar with the end surface; and wherein the frusto-conical surface extends from the end surface to the outside surface. 
         [0016]    In yet another exemplary embodiment, the inlet end portion includes an annular portion that extends from the intersection in an axial direction away from the outlet end portion. 
         [0017]    In certain exemplary embodiments, the frusto-conical surface extends from the intersection to the outside surface in an angular direction, an axial component of which extends axially away from the outlet end portion. 
         [0018]    In another exemplary embodiment, the inlet end portion includes an annular portion that extends from the intersection in an axial direction away from the outlet end portion. 
         [0019]    In a third aspect, there is provided a fluid cylinder for a pump assembly, and the fluid cylinder has a first axis and a second axis perpendicular thereto. The fluid cylinder includes a first fluid passage in which a first valve is adapted to be disposed and through which fluid flows along the first axis. The fluid passage includes a first passage portion defining a first inside diameter of the fluid passage; and a second passage portion extending from the first passage portion, the second passage portion defining a second inside diameter of the fluid passage; wherein the second inside diameter is less than the first inside diameter. A tapered internal shoulder is defined by the fluid passage, the tapered internal shoulder defining a frusto-conical surface, the frusto-conical surface defining an angle from the second axis; wherein the angle ranges from about 10 degrees to about 45 degrees measured from the second axis; and wherein at least a portion of the second passage portion is positioned along the first axis between the first passage portion and the first tapered internal shoulder. A pressure chamber is in fluid communication with the first fluid passage. 
         [0020]    In an exemplary embodiment, the second axis intersects the fluid passage at an intersection, the intersection defining a third diameter of the fluid passage; wherein the second passage portion defines an axially-extending cylindrical inside surface extending along the first axis, the axially-extending cylindrical inside surface having the second diameter; wherein the second diameter of the fluid passage is greater than the third diameter of the fluid passage; and wherein the frusto-conical surface extends between the intersection and the axially-extending cylindrical inside surface. 
         [0021]    In another exemplary embodiment, the frusto-conical surface extends from the intersection to the cylindrical inside surface in an angular direction, an axial component of which extends axially towards the first passage portion. 
         [0022]    In certain exemplary embodiments, the frusto-conical surface extends from the intersection to the outside surface in an angular direction, an axial component of which extends axially away from the outlet end portion. 
         [0023]    In other exemplary embodiments, the fluid cylinder includes a second fluid passage in which a second valve is adapted to be disposed and through which fluid flows along the first axis; and a fluid outlet passage in fluid communication with the pressure chamber via the second fluid passage. 
         [0024]    Other aspects, features, and advantages will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of the inventions disclosed. 
     
    
     
       DESCRIPTION OF FIGURES 
         [0025]    The accompanying drawings facilitate an understanding of the various embodiments. 
           [0026]      FIG. 1  is an elevational view of a reciprocating pump assembly according to an exemplary embodiment, and the pump assembly includes a fluid cylinder assembly. 
           [0027]      FIG. 2  is a sectional view of the fluid cylinder assembly of  FIG. 1  according to an exemplary embodiment, the fluid cylinder assembly includes a fluid cylinder and inlet and outlet valves, and each of the inlet and outlet valves includes a valve seat. 
           [0028]      FIG. 3  is an enlarged view of a portion of the section view of  FIG. 2 , according to an exemplary embodiment. 
           [0029]      FIG. 4  is a partial sectional view of respective portions of the valve seat and the fluid cylinder, according to another exemplary embodiment. 
           [0030]      FIG. 5  is a partial sectional view of respective portions of the valve seat and fluid cylinder, according to yet another exemplary embodiment. 
           [0031]      FIG. 6  is a partial sectional view of respective portions of the valve seat and fluid cylinder, according to still yet another exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    In an exemplary embodiment, as illustrated in  FIG. 1 , a reciprocating pump assembly is generally referred to by the reference numeral  10  and includes 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, the crankshaft being operably coupled to an engine or motor (not shown), which is adapted to drive the crankshaft. The fluid end portion  14  includes a fluid end block or fluid cylinder  18 , which is connected to the housing  16  via a plurality of stay rods  20 . The fluid cylinder  18  includes a fluid inlet passage  22  and a fluid outlet passage  24 , which are spaced in a parallel relation. A plurality of cover assemblies  26 , one of which is shown in  FIG. 1 , is connected to the fluid cylinder  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 cylinder  18  opposite the fluid inlet passage  22 . A plunger rod assembly  30  extends out of the housing  16  and into the fluid cylinder  18 . In several exemplary embodiments, the pump assembly  10  is freestanding on the ground, is mounted to a trailer that can be towed between operational sites, or is mounted to a skid. 
         [0033]    In an exemplary embodiment, 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 cylinder  18 , and into a pressure chamber  36  formed in the fluid cylinder  18 . In several exemplary embodiments, a plurality of parallel-spaced bores may be formed in the fluid cylinder  18 , with one of the bores being the bore  34 , a plurality of pressure chambers may be formed in the fluid cylinder  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 . At least the bore  34 , the pressure chamber  36 , and the plunger  32  together may be characterized as a plunger throw. In several exemplary embodiments, the reciprocating pump assembly  10  includes three plunger throws (i.e., a triplex pump assembly), or includes four or more plunger throws. 
         [0034]    As shown in  FIG. 2 , the fluid cylinder  18  includes inlet and outlet fluid passages  38  and  40  formed therein, which are generally coaxial along an 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 fluid inlet passage  38  includes an enlarged-diameter portion  38   a  and a reduced-diameter portion  38   b  extending downward therefrom (the diameter of the enlarged-diameter portion  38   a  is greater than the diameter of the reduced-diameter portion  38   b ). The fluid inlet passage  38  defines a tapered internal shoulder  43  so that the reduced-diameter portion  38   b  is positioned along the axis  42  between the enlarged diameter portion  38   a  and the tapered internal shoulder  43 . The tapered internal shoulder  43  defines a frusto-conical surface  44  of the fluid cylinder  18 . The reduced-diameter portion  38   b  defines an inside surface  46  of the fluid cylinder  18 , the inside surface  46  having the diameter of the reduced-diameter portion  38   b . Similarly, the fluid outlet passage  40  includes an enlarged-diameter portion  40   a  and a reduced-diameter portion  40   b  extending downward therefrom. The fluid outlet passage  40  defines a tapered internal shoulder  48  so that the reduced-diameter  40   b  is axially positioned between the enlarged-diameter portion  40   a  and the tapered internal shoulder  48 . The tapered internal shoulder  48  defines a frusto-conical surface  50  of the fluid cylinder  18 . The reduced-diameter portion  40   b  defines an inside surface  52  of the fluid cylinder  18 . 
         [0035]    An inlet valve assembly, or inlet valve  54 , is disposed in the fluid passage  38 , and engages at least the frusto-conical surface  44  and the inside surface  46 . Similarly, an outlet valve assembly, or outlet valve  56 , is disposed in the 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. 
         [0036]    A counterbore  58  is formed in the fluid cylinder  18 , and is generally coaxial with the axis  42 . The counterbore  58  defines an internal shoulder  58   a  and includes an internal threaded connection  58   b  adjacent the internal shoulder  58   a . A counterbore  60  is formed in the fluid cylinder  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 several exemplary embodiments, the fluid cylinder  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 . Similarly, in several exemplary embodiments, the fluid cylinder  18  may include another 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 . 
         [0037]    A plug  64  is disposed in the counterbore  58 , engaging the internal shoulder  58   a  and sealingly engaging an inside cylindrical surface defined by the reduced-diameter portion of the counterbore  58 . An external threaded connection  66   a  of a fastener  66  is threadably engaged with the internal threaded connection  58   b  of the counterbore  58  so that an end portion of the fastener  66  engages the plug  64 . As a result, the fastener  66  sets or holds the plug  64  in place against the internal shoulder  58   a  defined by the counterbore  58 , thereby maintaining the sealing engagement of the plug  64  against the inside cylindrical surface defined by the reduced-diameter portion of the counterbore  58 . The cover assembly  28  shown in  FIGS. 1 and 2  includes at least the plug  64  and the fastener  66 . In an exemplary embodiment, the cover assembly  28  may be disconnected from the fluid cylinder  18  to provide access to, for example, the counterbore  58 , the pressure chamber  36 , the plunger  32 , the fluid passage  40  or the outlet valve  56 . The cover assembly  28  may then be reconnected to the fluid cylinder  18  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  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 . 
         [0038]    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  maybe 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 the inside cylindrical surface defined by the reduced-diameter portion of the counterbore  60 . The cover assembly  26  shown in  FIGS. 1 and 2  includes at least the plug  68  and the fastener  70 . In an exemplary embodiment, the cover assembly  26  may be disconnected from the fluid cylinder  18  to provide access to, for example, the counterbore  60 , the pressure chamber  36 , the plunger  32 , the fluid passage  38 , or the inlet valve  54 . The cover assembly  26  may then be reconnected to the fluid cylinder  18  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 . 
         [0039]    A valve spring retainer  72  is disposed in the enlarged-diameter portion  38   a  of the fluid passage  38 . The valve spring retainer  72  is connected to the end portion of the plug  68  opposite the fastener  70 . In an exemplary embodiment, and as shown in  FIG. 2 , the valve spring retainer  72  is connected to the plug  68  via a hub  74 , which is generally coaxial with the axis  62 . 
         [0040]    In an exemplary embodiment, as illustrated in  FIG. 3  with continuing reference to  FIGS. 1 and 2 , the inlet valve  54  includes a valve seat  76  and a valve member  78  engaged therewith. The valve seat  76  includes a seat body  80  having an inlet end portion  81  and an outlet end portion  82 . The seat body  80  is disposed in the reduced-diameter portion  38   b  of the fluid passage  38 . A bore  83  is formed through the seat body  80  and is coaxial with an axis  84 , which is aligned with the axis  42  when the inlet valve  54  is disposed in the fluid passage  38 , as shown in  FIG. 3 . The outlet end portion  82  is axially opposed to the inlet end portion  81  along the axis  84  and thus along the axis  42 . The bore  83  defines an inside surface  85  of the seat body  80 . An outside surface  86  of the seat body  80  contacts the inside surface  46  defined by the fluid passage  38 . In an exemplary embodiment, the outside surface  86  may be cylindrical. In an exemplary embodiment, the outside surface  86  may be slightly conical. A sealing element, such as an o-ring, may be disposed in an annular groove formed in the outside surface  86 , and the o-ring may sealingly engage the inside surface  46 . The fluid cylinder  18  and valve seat  76  have axes  88  and  90 , respectively. The axes  88  and  90  are coaxial when the inlet valve  54  is disposed in the fluid passage  38 , as shown in  FIG. 3 . The axes  88  and  90  are perpendicular to the axes  42  and  84 , respectively. 
         [0041]    A frusto-conical surface  91  is defined by the inlet end portion  81  of the seat body  80 . The frusto-conical surface  91  defines an angle  92  from the axis  90  and thus also from the axis  88 . Similarly, the frusto-conical surface  44  defines an angle  93  from the axis  88  and thus also from the axis  90 . In an exemplary embodiment, each of the angles  92  and  93  ranges from about 10 degrees to about 45 degrees measured from the aligned axes  88  and  90 . In an exemplary embodiment, each of the angles  92  and  93  ranges from about 15 degrees to about 45 degrees measured from the aligned axes  88  and  90 . In an exemplary embodiment, the angles  92  and  93  are equal as measured from the aligned axes  88  and  90 . In an exemplary embodiment, each of the angles  92  and  93  is about 30 degrees measured from the aligned axes  88  and  90 . In an exemplary embodiment, the angles  92  and  93  are not equal as measured from the aligned axes  88  and  90 . An end surface  94  is defined by inlet end portion  81  of the seat body  80 . The end surface  94  faces axially away from the outlet end portion  82 . The end surface  94  is coplanar with the aligned axes  88  and  90 . The frusto-conical surface  91  extends from the intersection between the seat body  80  and the aligned axes  88  and  90 , which intersection corresponds to the end surface  94 , to the outside surface  86  in an angular direction, an axial component of which extends axially towards the outlet end portion  82 . Likewise, the frusto-conical surface  44  extends from the intersection between the fluid passage  38  and the aligned axes  88  and  90 , and to the inside surface  46  in an angular direction, an axial component of which extends axially towards the enlarged-diameter portion  38   a.    
         [0042]    A diameter  95   a  is defined by the intersection between the seat body  80  and the aligned axes  88  and  90 ; similarly, a diameter of the fluid passage  38  generally corresponding, or about equal, to the diameter  95   a  is defined by the intersection between the fluid passage  38  and the aligned axes  88  and  90 . A diameter  95   b  is defined by the outside surface  86 ; the diameter of the reduced-diameter portion  38   b  of the fluid passage  38  generally corresponds, or is about equal, to the diameter  95   b . The diameter  95   b  is greater than the diameter  95   a.    
         [0043]    The outlet end portion  82  defines a tapered surface  96 , which extends angularly upward from the inside surface  85 . In an exemplary embodiment, the tapered surface  96  extends at an angle relative to the aligned axes  42  and  84 , which angle ranges from about 15 degrees to about 45 degrees. 
         [0044]    The seat body  80  of the valve seat  76  is disposed within the reduced-diameter portion  38   b  of the fluid passage  38  so that the outside surface  86  of the seat body  80  engages the inside surface  46  of the fluid cylinder  18 . In an exemplary embodiment, the seat body  80  forms an interference fit, or is press fit, in the portion  38   b  of the fluid passage  38  so that the valve seat  76  is prevented from being dislodged from the fluid passage  38 . As noted above, a sealing element, such as an o-ring, may be disposed in an annular groove formed in the outside surface  86 , and the o-ring may sealingly engage the inside surface  46 . 
         [0045]    The valve member  78  includes a central stem  98 , from which a valve body  100  extends radially outward. An outside annular cavity  102  is formed in the valve body  100 . A seal  104  extends within the cavity  102 , and is adapted to sealingly engage the tapered surface  96  of the valve seat  76 , under conditions to be described below. A plurality of circumferentially-spaced legs  106  extend angularly downward from the central stem  98 , and slidably engage the inside surface  85  of the seat body  80 . In several exemplary embodiments, the plurality of legs  106  may include two, three, four, five, or greater than five, legs  106 . A lower end portion of a spring  108  is engaged with the top of the valve body  100  opposite the central stem  98 . As shown in  FIG. 2 , the upper end portion of the spring  108  is engaged with the valve spring retainer  72 . The valve member  78  is movable, relative to the valve seat  76  and thus the fluid cylinder  18 , between a closed position (shown in  FIG. 3 ) and an open position (not shown), under conditions to be described below. 
         [0046]    In an exemplary embodiment, the seal  104  is molded in place in the valve body  100 . In an exemplary embodiment, the seal  104  is preformed and then attached to the valve body  100 . In several exemplary embodiments, the seal  104  is composed of one or more materials such as, for example, a deformable thermoplastic material, a urethane material, a fiber-reinforced material, carbon, glass, cotton, wire fibers, cloth, and/or any combination thereof. In an exemplary embodiment, the seal  104  is composed of a cloth which is disposed in a thermoplastic material, and the cloth may include carbon, glass, wire, cotton fibers, and/or any combination thereof. In several exemplary embodiments, the seal  104  is composed of at least a fiber-reinforced material, which can prevent or at least reduce delamination. In an exemplary embodiment, the seal  104  has a hardness of 95 A durometer or greater, or a hardness of 69 D durometer or greater. In another exemplary embodiment, the seal  104  has a hardness of 95 A durometer or lesser. In several exemplary embodiments, the valve body  100  is much harder and more rigid than the seal  104 . 
         [0047]    The outlet valve  56  is identical to the inlet valve  54  and therefore will not be described in further detail. Features of the outlet valve  56  that are identical to corresponding features of the inlet valve  54  will be given the same reference numerals as that of the inlet valve  54 . The outlet valve  56  is disposed in the fluid passage  40 , and engages the fluid cylinder  18 , in a manner that is identical to the manner in which the inlet valve  54  is disposed in the fluid passage  38 , and engages the fluid cylinder  18 , with one exception involving the spring  108  of the outlet valve  56 ; more particularly, the upper portion of the spring  108  of the outlet valve  56  is compressed against the bottom of the plug  64 , rather than being compressed against a component that corresponds to the valve spring retainer  72 , against which the upper portion of the spring  108  of the inlet valve  54  is compressed. 
         [0048]    In operation, in an exemplary embodiment, with continuing reference to  FIGS. 1-3 , the plunger  32  reciprocates within the bore  34 , reciprocating in and out of the pressure chamber  36 . That is, the plunger  32  moves back and forth horizontally, as viewed in  FIG. 2 , away from and towards the axis  42 . In an exemplary embodiment, the engine or motor (not shown) drives the crankshaft (not shown) enclosed within the housing  16 , thereby causing the plunger  32  to reciprocate within the bore  34  and thus in and out of the pressure chamber  36 . 
         [0049]    As the plunger  32  reciprocates out of the pressure chamber  36 , the inlet valve  54  is opened. More particularly, as the plunger  32  moves away from the axis  42 , the pressure inside the pressure chamber  36  decreases, creating a differential pressure across the inlet valve  54  and causing the valve member  78  to move upward, as viewed in  FIGS. 2 and 3 , relative to the valve seat  76  and the fluid cylinder  18 . As a result of the upward movement of the valve member  78 , the spring  108  is compressed between the valve body  100  and the valve spring retainer  72 , the seal  104  disengages from the tapered surface  96 , and the inlet valve  54  is thus placed in its open position. Fluid in the fluid inlet passage  22  flows along the axis  42  and through the fluid passage  38  and the inlet valve  54 , being drawn into the pressure chamber  36 . To flow through the inlet valve  54 , the fluid flows into the bore  83  at the inlet end portion  81 , through the bore  83  and along the aligned axes  42  and  84 , and out of the bore  83  at the outlet end portion  82 . During this time, the outlet valve  56  is in its closed position, with the seal  104  of the valve member  78  of the outlet valve  56  engaging the tapered surface  96  of the valve seat  76  of the outlet valve  56 . Fluid continues to be drawn into the pressure chamber  36  until the plunger  32  is at the end of its stroke away from the axis  42 . At this point, the differential pressure across the inlet valve  54  is such that the spring  108  of the inlet valve  54  is not further compressed, or begins to decompress and extend, forcing the valve member  78  of the inlet valve  54  to move downward, as viewed in  FIGS. 2 and 3 , relative to the valve seat  76  and the fluid cylinder  18 . As a result, the inlet valve  54  is placed in, or begins to be placed in, its closed position, with the seal  104  sealingly engaging, or at least moving towards, the tapered surface  96 . 
         [0050]    As the plunger  32  moves into the pressure chamber  36  and thus towards the axis  42 , the pressure within the pressure chamber  36  begins to increase. The pressure within the pressure chamber  36  continues to increase until the differential pressure across the outlet valve  56  exceeds a predetermined set point, at which point the outlet valve  56  opens and permits fluid to flow out of the pressure chamber  36 , along the axis  42  and through the fluid passage  40  and the outlet valve  56 , and into the fluid outlet passage  24 . As the plunger  32  reaches the end of its stroke towards the axis  42  (i.e., its discharge stroke), the inlet valve  54  is in, or is placed in, its closed position, with the seal  104  sealingly engaging the tapered surface  96 . 
         [0051]    The foregoing is repeated, with the reciprocating pump assembly  10  pressurizing the fluid as the fluid flows from the fluid inlet passage  22  and to the fluid outlet passage  24  via the pressure chamber  36 . In an exemplary embodiment, the pump assembly  10  is a single-acting reciprocating pump, with fluid being pumped across only one side of the plunger  32 . 
         [0052]    In an exemplary embodiment, during the above-described operation of the reciprocating pump assembly  10 , the taper of each of the surfaces  44  and  91  balances the loading forces applied thereagainst. In an exemplary embodiment, the loading is distributed across the surfaces  44  and  91 , reducing stress concentrations. 
         [0053]    In an exemplary embodiment, as illustrated in  FIG. 4  with continuing reference to  FIGS. 1-3 , the end surface  94  is omitted from the inlet end portion  81 . Instead, the inlet end portion  81  includes an annular portion  108  that extends from the intersection between the seat body  80  and the aligned axes  88  and  90  in an axial direction away from the outlet end portion  82 . An end surface  110  is defined by the annular portion  108  of the inlet end portion  81 . The end surface  110  faces axially away from the outlet end portion  82 . In an exemplary embodiment, the operation of the pump assembly  10  with the exemplary embodiment of the valve seat  76  illustrated in  FIG. 4  is identical to the operation of the pump assembly  10  with the exemplary embodiment of the valve seat  76  illustrated in  FIG. 3 . The annular portion  108  facilitates the removal of the valve seat  76  from the fluid cylinder  18 . 
         [0054]    In an exemplary embodiment, as illustrated in  FIG. 5  with continuing reference to  FIGS. 1-4 , the tapered internal shoulder  43  and the frusto-conical surface  44  are omitted. Instead, the fluid inlet passage  38  defines a tapered internal shoulder  43 ′ so that the majority of the reduced-diameter portion  38   b  is axially positioned between the enlarged diameter portion  38   a  and the tapered internal shoulder  43 ′. The tapered internal shoulder  43 ′ defines a frusto-conical surface  44 ′ of the fluid cylinder  18 . The frusto-conical surface  91  is omitted in favor of a frusto-conical surface  91 ′, which is defined by the inlet end portion  81  of the seat body  80 . The frusto-conical surface  91 ′ extends from the intersection between the seat body  80  and the aligned axes  88  and  90 , and to the outside surface  86  in an angular direction, an axial component of which extends axially away the outlet end portion  82 . Likewise, the frusto-conical surface  44 ′ extends from the intersection between the fluid passage  38  and the aligned axes  88  and  90 , and to the inside surface  46  in an angular direction, an axial component of which extends away from the enlarged-diameter portion  38   a . The frusto-conical surface  91 ′ defines an angle  92 ′ from the axis  90  and thus also from the axis  88 . Similarly, the frusto-conical surface  44 ′ defines an angle  93 ′ from the axis  88  and thus also from the axis  90 . In an exemplary embodiment, each of the angles  92 ′ and  93 ′ ranges from about 10 degrees to about 45 degrees measured from the aligned axes  88  and  90 . In an exemplary embodiment, each of the angles  92 ′ and  93 ′ ranges from about 15 degrees to about 45 degrees measured from the aligned axes  88  and  90 . In an exemplary embodiment, the angles  92 ′ and 93′ are equal as measured from the aligned axes  88  and  90 . In an exemplary embodiment, each of the angles  92 ′ and  93 ′ is about 30 degrees measured from the aligned axes  88  and  90 . In an exemplary embodiment, the angles  92 ′ and  93 ′ are not equal as measured from the aligned axes  88  and  90 . In an exemplary embodiment, the operation of the pump assembly  10  with the respective exemplary embodiments of the valve seat  76  and the fluid cylinder  18  illustrated in  FIG. 5 , is identical to the operation of the pump assembly  10  with the respective exemplary embodiments of the valve seat  76  and the fluid cylinder  18  illustrated in  FIG. 3 . The annular portion  108  facilitates the removal of the valve seat  76  from the fluid cylinder  18 . 
         [0055]    In an exemplary embodiment, during operation of the pump assembly  10  using any of the foregoing embodiments of the inlet valve  54 , downwardly directed axial loads along the axis  42  are applied against the top of the valve body  100 . This loading is usually greatest as the plunger  32  moves towards the axis  42  and the outlet valve  56  opens and permits fluid to flow out of the pressure chamber  36 , through the fluid passage  40  and the outlet valve  56 , and into the fluid outlet passage  24 . As the plunger  32  reaches the end of its stroke towards the axis  42  (its discharge stroke), the inlet valve  54  is in, or is placed in, its closed position, and the loading applied to the top of the valve body  100  is transferred to the seal  104  via the valve body  100 . The loading is then transferred to the valve seat  76  via the seal  104 , and then is distributed and transferred to the tapered internal shoulder  43  or  43 ′ of the fluid cylinder  18  via the engagement of the surface  91  or  91 ′ against the surface  44  or  44 ′. The tapering of the surface  91  or  91 ′ and the surface  44  or  44 ′ facilitates this distribution and transfer of the downwardly directed axial loading to the fluid cylinder  18  in a balanced manner, thereby reducing stress concentrations in the fluid cylinder  18  and the valve seat  76 . 
         [0056]    In several experimental exemplary embodiments, experimental analyses were conducted on two experimental exemplary embodiments of combinations of the valve seat  76  and the fluid cylinder  18 . Experimental Exemplary Embodiment #1, for which finite element analysis (FEA) was conducted, was the combination of the valve seat  76  and the fluid cylinder  18  as illustrated in  FIG. 6 . As shown in  FIG. 6 , the tapered internal shoulder  43  of the fluid cylinder  18  is omitted. The seat body  80  of the valve seat  76  includes an enlarged-diameter portion  112  and a reduced-diameter portion  114  extending downwardly therefrom. An external shoulder  116  defines an axially-facing surface  118  that faces axially towards the inlet end portion  81 . The axially-facing surface  118  engages an axially-facing surface  120  of the fluid cylinder  18 , which is defined by the enlarged-diameter portion  38   a  and faces axially away from the inlet end portion  81 . Experimental Exemplary Embodiment #2, for which FEA was conducted, was the combination of the valve seat  76  and the fluid cylinder  18  as illustrated in  FIG. 3 . Using a loading of about 17 ksi, the maximum experimental stresses were determined in each of Experimental Exemplary Embodiments #1 and #2. For Experimental Exemplary Embodiment #1, the maximum von-Mises stress in response to the engagement of the valve seat  76  with the fluid cylinder  18  was about 142 ksi at about Point A shown in  FIG. 6 . For Experimental Exemplary Embodiment #2, the maximum von-Mises stress in response to the engagement of the valve seat  76  with the fluid cylinder  18  was about 78 ksi at about Point B, and about 78 ksi at about Point C (Points B and C are shown in  FIG. 3 ). 
         [0057]    In several exemplary embodiments, variations may be made to the valve member  100 , or the valve member  100  may be omitted in favor of another valve member that does not include the plurality of legs  106 . In several exemplary embodiments, the valves  54  and  56  may be configured to operate in the presence of highly abrasive fluids, such as drilling mud, and at relatively high pressures, such as at pressures of up to about 15,000 psi or greater. In several exemplary embodiments, instead of, or in addition to being used in reciprocating pumps, the valves  54  and  56  or the components thereof, such as the valve seat  76 , may be used in other types of pumps and fluid systems. Correspondingly, instead of, or in addition to being used in reciprocating pumps, the fluid cylinder  18  or features thereof may be used in other types of pumps and fluid systems. 
         [0058]    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. 
         [0059]    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. 
         [0060]    In addition, the foregoing describes only some embodiments of the invention(s), and alterations, modifications, additions and/or changes can be made thereto without departing from the scope and spirit of the disclosed embodiments, the embodiments being illustrative and not restrictive. 
         [0061]    Furthermore, invention(s) have described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention(s). Also, the various embodiments described above may be implemented in conjunction with other embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realize yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment.