Patent Publication Number: US-2019170138-A1

Title: Pump assembly including fluid cylinder and tapered valve seats

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 15/355,609, filed Nov. 18, 2016, which is a continuation of U.S. patent application Ser. No. 29/546,567, filed Nov. 24, 2015, now U.S. Pat. No. D787,029, issued May 16, 2017, which is a continuation of U.S. patent application Ser. No. 29/446,059, filed Feb. 20, 2013, now U.S. Pat. No. D748,228, issued Jan. 26, 2016, which is a continuation of U.S. patent application Ser. No. 13/755,217, filed Jan. 31, 2013; the entire disclosures of U.S. patent application Ser. Nos. 15/355,609, 29/546,567, 29/446,059, and 13/755,217 are hereby incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     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 
     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. Moreover, it is sometimes difficult to remove valve seats from the fluid cylinder for replacement, which difficulty may result in damage to the fluid cylinder. Further, when replacing a worn valve seat or producing a new pump assembly, an incorrect valve seat may unintentionally be disposed in the fluid cylinder, which may hurt pump performance and possibly damage the fluid cylinder or valve seat. In many cases, this mix-up of parts is possible because differences between valve seats may not be easily discernable upon visual inspection. Therefore, what is needed is an apparatus or method that addresses one or more of the foregoing issues, among others. 
     SUMMARY 
     In a first aspect, there is provided a pump assembly that includes a fluid cylinder having a first axis, the fluid cylinder includes a first fluid passage through which fluid is adapted to flow 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 angle from the first axis; and 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 having a second axis that is aligned with the first axis, the first valve seat includes a first tapered external shoulder, the first tapered external shoulder defining a second angle from the second axis; wherein each of the first and second angles ranges from about 10 degrees to about 45 degrees measured from the first axis and the second axis aligned therewith. 
     In an exemplary embodiment, the first tapered internal shoulder and the first tapered external shoulder define first and second frusto-conical surfaces, respectively; and wherein the first tapered internal shoulder engages the first tapered external shoulder to distribute and transfer loading between the first and second frusto-conical surfaces. 
     In certain exemplary embodiments, the first and second angles are equal. 
     In another exemplary embodiment, each of the first and second angles is about 30 degrees measured from the first axis and the second axis aligned therewith. 
     In certain exemplary embodiments, the fluid cylinder further includes a pressure chamber in fluid communication with the first fluid passage; a second fluid passage in fluid communication with the pressure chamber and through which fluid is adapted to flow along the first axis, the second fluid passage defining a second tapered internal shoulder of the fluid cylinder, the second tapered internal shoulder defining a third angle from the first axis; a fluid inlet passage in fluid communication with the pressure chamber via the first fluid passage; and a fluid outlet passage in fluid communication with the pressure chamber via the second fluid passage; wherein the pump assembly further includes a second valve to control flow of the fluid through the second fluid passage, the second valve includes a second valve seat disposed in the second fluid passage, the second valve seat having a third axis that is aligned with each of the first and second axes, the second valve seat includes a second tapered external shoulder, the second tapered external shoulder defining a fourth angle from the third axis; and wherein each of the third and fourth angles ranges from about 10 degrees to about 45 degrees measured from the first axis and each of the second and third axes aligned therewith. 
     In another exemplary embodiment, the second tapered internal shoulder and the second tapered external shoulder defines third and fourth frusto-conical surfaces, respectively; and wherein the second tapered internal shoulder engages the second tapered external shoulder to distribute and transfer loading between the third and fourth frusto-conical surfaces. 
     In yet another exemplary embodiment, the third and fourth angles are equal. 
     In an exemplary embodiment, each of the third and fourth angles is about 30 degrees measured from the first axis and each of the second and third axes aligned therewith. 
     In another exemplary embodiment, the first valve seat further includes a seat body, the seat body includes an enlarged-diameter portion at one end thereof, the enlarged-diameter portion includes the first tapered external shoulder and defining a first cylindrical surface extending axially from the first frusto-conical surface, the first cylindrical surface defining a first outside diameter; a bore formed through the seat body, the bore defining a second cylindrical surface, the second cylindrical surface defining a first inside diameter; wherein the first fluid passage includes an enlarged-diameter portion and a reduced-diameter portion extending axially therefrom; wherein the enlarged-diameter portion of the first fluid passage defines the first tapered internal shoulder of the fluid cylinder; wherein the reduced-diameter portion of the first fluid passage defines an inside surface of the fluid cylinder and a second inside diameter; wherein the enlarged-diameter portion of the seat body is disposed in the enlarged-diameter portion of the first fluid passage; wherein the seat body defines an outside surface that is engaged with the inside surface of the fluid cylinder; and wherein the outside surface defines a second outside diameter. 
     In yet another exemplary embodiment, at least one of the inside surface of the fluid cylinder and the outside surface of the seat body is tapered at a taper angle from the first axis and the second axis aligned therewith, the taper angle ranging from greater than 0 degrees to about 5 degrees measured from the first axis and the second axis aligned therewith. 
     In an exemplary embodiment, the first valve seat further includes an annular groove formed in the outside surface of the seat body, the annular groove defining a groove diameter; and a sealing element disposed in the annular groove and sealingly engaging the inside surface of the fluid cylinder. 
     In another exemplary embodiment, each of the first and second angles is about 30 degrees; wherein the first outside diameter is about 5 inches; wherein the first inside diameter is about 3 inches; wherein the second inside diameter is about 4.5 inches; wherein the groove diameter is about 4 inches; and wherein the second outside diameter is about 4.5 inches. 
     In yet another exemplary embodiment, the fluid cylinder further includes a pressure chamber in fluid communication with the first fluid passage; and wherein the pump assembly further includes a housing connected to the fluid cylinder, and a plunger rod assembly extending out of the housing and into the pressure chamber. 
     In a second aspect, a fluid cylinder for a pump assembly is provided, the fluid cylinder having a fluid passage axis and includes a first fluid passage through which fluid is adapted to flow along the fluid passage axis, the first fluid passage defining a first tapered internal shoulder of the fluid cylinder, the first tapered internal shoulder defining a first angle from the fluid passage axis, the first angle ranging from about 10 degrees to about 45 degrees measured from the fluid passage axis; and a pressure chamber in fluid communication with the first fluid passage. 
     In certain exemplary embodiment, the first angle is about 30 degrees measured from the fluid passage axis. 
     In an exemplary embodiment, the fluid cylinder includes a second fluid passage in fluid communication with the pressure chamber and through which fluid is adapted to flow along the fluid passage axis, the second fluid passage defining a second tapered internal shoulder of the fluid cylinder, the second tapered internal shoulder defining a second angle from the fluid passage axis; and a fluid outlet passage in fluid communication with the pressure chamber via the second fluid passage; wherein the second angle ranges from about 10 degrees to about 45 degrees measured from the fluid passage axis. 
     In another exemplary embodiment, the first and second angles are equal. 
     In yet another exemplary embodiment, each of the first and second angles is about 30 degrees measured from the fluid passage axis. 
     In certain exemplary embodiments, the first fluid passage includes an enlarged-diameter portion and a reduced-diameter portion extending axially therefrom; wherein the enlarged-diameter portion of the first fluid passage defines the first tapered internal shoulder of the fluid cylinder; and wherein the reduced-diameter portion of the first fluid passage defines an inside surface of the fluid cylinder and an inside diameter. 
     In another exemplary embodiment, the inside surface is tapered at a taper angle from the fluid passage axis, the taper angle ranging from greater than 0 degrees to about 5 degrees measured from the fluid passage axis. 
     In an exemplary embodiment, each of the first and second angles is about 30 degrees; and wherein the inside diameter is about 4.5 inches. 
     In a third aspect, there is provided a valve seat adapted to be disposed within a fluid cylinder for a pump assembly, the valve seat having a valve seat axis and includes a seat body, the seat body includes an enlarged-diameter portion at one end thereof, the enlarged-diameter portion includes a first tapered external shoulder, the first tapered external shoulder defining a first angle from the valve seat axis, and a frusto-conical surface extending at the first angle from the valve seat axis, the first angle ranging from about 10 degrees to about 45 degrees measured from the valve seat axis, wherein the enlarged-diameter portion defines a first cylindrical surface extending axially from the frusto-conical surface, the first cylindrical surface defining a first outside diameter, wherein the seat body defines an outside surface, the outside surface defining a second outside diameter that is less than the first outside diameter, and wherein the frusto-conical surface is axially disposed between the outside surface and the first cylindrical surface; and a bore formed through the seat body and through which fluid flows along the valve seat axis, the bore defining a second cylindrical surface, the second cylindrical surface defining an inside diameter that is less than the second outside diameter. 
     In an exemplary embodiment, the first angle is about 30 degrees measured from the valve seat axis. 
     In another exemplary embodiment, the outside surface of the seat body is tapered at a second angle from the valve seat axis; and wherein the second angle ranges from greater than 0 degrees to about 5 degrees measured from the valve seat axis. 
     In yet another exemplary embodiment, the valve seat includes an annular groove formed in the outside surface of the seat body, the annular groove defining a groove diameter that is less than the second outside diameter and greater than the inside diameter; and a sealing element disposed in the annular groove. 
     In certain exemplary embodiments, the first angle is about 30 degrees measured from the valve seat axis; wherein the first outside diameter is about 5 inches; wherein the inside diameter is about 3 inches; wherein the groove diameter is about 4 inches; and wherein the second outside diameter is about 4.5 inches. 
     In a fourth aspect, there is provided a valve seat adapted to be disposed within a fluid cylinder for a pump assembly, the valve seat having a valve seat axis and includes a seat body, the seat body includes an enlarged-diameter portion at one end thereof, the enlarged-diameter portion includes a first tapered external shoulder, the first tapered external shoulder defining a first angle from the valve seat axis, and a frusto-conical surface extending at the first angle from the valve seat axis, wherein the enlarged-diameter portion defines a first cylindrical surface extending axially from the frusto-conical surface, the first cylindrical surface defining a first outside diameter, wherein the seat body defines an outside surface, the outside surface defining a second outside diameter that is less than the first outside diameter, wherein the outside surface of the seat body is tapered at a second angle from the valve seat axis, and wherein the frusto-conical surface is axially disposed between the outside surface and the first cylindrical surface; and a bore formed through the seat body and through which fluid flows along the valve seat axis, the bore defining a second cylindrical surface, the second cylindrical surface defining an inside diameter that is less than the second outside diameter. 
     In an exemplary embodiment, the first angle ranges from about 10 degrees to about 45 degrees measured from the valve seat axis; and wherein the second angle ranges from greater than 0 degrees to about 5 degrees measured from the valve seat axis. 
     In another exemplary embodiment, the first angle is about 30 degrees measured from the valve seat axis; and wherein the second angle ranges from greater than 0 degrees to about 5 degrees measured from the valve seat axis. 
     In yet another exemplary embodiment, the valve seat includes an annular groove formed in the outside surface of the seat body, the annular groove defining a groove diameter that is less than the second outside diameter and greater than the inside diameter; and a sealing element disposed in the annular groove. 
     In an exemplary embodiment, the first angle is about 30 degrees measured from the valve seat axis; wherein the second angle ranges from greater than 0 degrees to about 5 degrees measured from the valve seat axis; wherein the first outside diameter is about 5 inches; wherein the inside diameter is about 3 inches; wherein the groove diameter is about 4 inches; and wherein the second outside diameter is about 4.5 inches. 
     In a fifth aspect, there is provided a method of producing a first pump assembly based on a second pump assembly, the first and second pump assemblies includes first and second fluid cylinders, respectively, and first and second valve seats, respectively, the first and second fluid cylinders includes first and second fluid passages formed therein, respectively, in which the first and second valve seats are adapted to be disposed, respectively, the first and second fluid passages defining first and second inside diameters, respectively, the first and second valve seats defining first and second outside diameters, respectively, the method includes producing the first fluid cylinder, includes sizing the first inside diameter to be less than the second outside diameter so that the second valve seat is not permitted to be disposed in the first fluid passage; and producing the first valve seat, includes sizing the first outside diameter so that: the first outside diameter is less than the second inside diameter; and a radial clearance would be defined between the first valve seat and an inside surface of the second fluid cylinder defined by the second fluid passage if the first valve seat were to be disposed in the second fluid passage. As a result, operational incompatibility between parts of the first and second pump assemblies is ensured and a long-term mix-up between parts is avoided. 
     In an exemplary embodiment, the method includes disposing the first valve seat in the first fluid passage. 
     In another exemplary embodiment, producing the first valve seat includes forming an enlarged-diameter portion, the enlarged-diameter portion includes a tapered external shoulder, the tapered external shoulder defining a first angle, the enlarged-diameter portion defining a cylindrical surface, the cylindrical surface defining a third outside diameter that is greater than the first outside diameter; wherein producing the first fluid cylinder includes forming the first fluid passage so that the first fluid passage defines a tapered internal shoulder, the tapered internal shoulder defining a second angle. 
     In yet another exemplary embodiment, producing the first valve seat further includes forming a bore through the first valve seat, the bore defining a third inside diameter that is less than the first outside diameter; forming an annular groove in the first valve seat, the annular groove defining a groove diameter that is less than the first outside diameter and greater than the third inside diameter; and disposing a sealing element in the annular groove. 
     In certain exemplary embodiments, the method includes disposing the first valve seat in the first fluid passage of the first cylinder so that: the tapered external shoulder engages the tapered internal shoulder, and the sealing element sealingly engages the fluid cylinder. 
     In other exemplary embodiments, each of the first and second angles is about 30 degrees relative to an axis; wherein the third outside diameter is about 5 inches; wherein the third inside diameter is about 3 inches; wherein the first inside diameter is about 4.5 inches; wherein the groove diameter is about 4 inches; and wherein the first outside diameter is about 4.5 inches. 
     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 
       The accompanying drawings facilitate an understanding of the various embodiments. 
         FIG. 1  is an elevational view of a reciprocating pump assembly according to an exemplary embodiment, the pump assembly includes a fluid cylinder assembly. 
         FIG. 2  is a section view of the fluid cylinder assembly of  FIG. 1  according to an exemplary embodiment, the fluid cylinder assembly including a fluid cylinder and inlet and outlet valves, the inlet and outlet valves each including a valve seat. 
         FIG. 3  is an enlarged view of a portion of the section view of  FIG. 2 , according to an exemplary embodiment. 
         FIG. 4  is a section view of respective portions of the valve seat and the fluid cylinder, according to another exemplary embodiment. 
         FIG. 5  is a section view of respective portions of the valve seat and fluid cylinder, according to yet another exemplary embodiment. 
         FIG. 6  is a section view of a valve according to another exemplary embodiment, the valve including a valve seat. 
         FIG. 7  is a perspective view of the valve seat of  FIG. 6 , according to an exemplary embodiment. 
         FIG. 8  is a sectional view of the valve seat of  FIGS. 6 and 7 , according to an exemplary embodiment. 
         FIG. 9  is a sectional view of the valve of  FIG. 6  disposed within the fluid cylinder of  FIG. 2 , according to an exemplary embodiment. 
         FIG. 10  is a flow chart illustration of a method of producing a new pump assembly based on a previously sold pump assembly referred to as Legacy or the Legacy model, according to an exemplary embodiment. 
         FIG. 11  is a sectional view of a valve seat, according to another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
     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. 
     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 a fluid passage axis  42 . Under conditions to be described below, fluid is adapted to flow through the inlet and outlet fluid passages  38  and  40  and along the fluid passage axis  42 . The fluid inlet passage  22  is in fluid communication with the pressure chamber  36  via the inlet fluid passage  38 . The pressure chamber  36  is in fluid communication with the fluid outlet passage  24  via the outlet fluid passage  40 . The fluid inlet passage  38  includes an enlarged-diameter portion  38   a  and a reduced-diameter portion  38   a  extending downward therefrom. The enlarged-diameter portion  38   a  defines a tapered internal shoulder  43  and thus a frusto-conical surface  44  of the fluid cylinder  18 . The reduced-diameter portion  38   a  defines an inside surface  46  of the fluid cylinder  18 . Similarly, the fluid outlet passage  40  includes an enlarged-diameter portion  40   a  and a reduced-diameter portion  40   b  extending downward therefrom. The enlarged-diameter portion  40   a  defines a tapered internal shoulder  48  and thus a frusto-conical surface  50  of the fluid cylinder  18 . The reduced-diameter portion  40   b  defines an inside surface  52  of the fluid cylinder  18 . 
     An 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  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. 
     A counterbore  58  is formed in the fluid cylinder  18 , and is generally coaxial with the fluid passage  42 . The counterbore  58  defines an internal shoulder  58   a  and includes an internal threaded connection  58   a  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 . 
     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   a  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 . 
     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 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 . 
     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 . 
     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 enlarged-diameter portion  82  at one end thereof. The enlarged-diameter portion  82  of the seat body  80  is disposed in the enlarged-diameter portion  38   a  of the fluid passage  38 . A bore  83  is formed through the seat body  80 . The valve seat  76  has a valve seat axis  84 , which is aligned with the fluid passage axis  42  when the inlet valve  54  is disposed in the fluid passage  38 , as shown in  FIG. 3 . Under conditions to be described below, fluid flows through the bore  83  and along the valve seat axis  84 . 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 . A sealing element, such as an o-ring  88 , is disposed in an annular groove  90  formed in the outside surface  86 . The o-ring  88  sealingly engages the inside surface  46 . The enlarged-diameter portion  82  includes a tapered external shoulder  91  and thus defines a frusto-conical surface  92 , which extends angularly upward from the outside surface  86 . The portion  82  further defines a cylindrical surface  94 , which extends axially upward from the extent of the frusto-conical surface  92 . The frusto-conical surface  92  is axially disposed between the outside surface  86  and the cylindrical surface  94 . The portion  82  further 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 from the valve seat axis  84 , which angle ranges from about 15 degrees to about 45 degrees. The seat body  80  of the valve seat  76  is disposed within the reduced-diameter portion  38   a  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   a  of the fluid passage  38  so that the valve seat  76  is prevented from being dislodged from the fluid passage  38 . 
     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 . 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. 
     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 several exemplary embodiments, the valve body  100  is much harder and more rigid than the seal  104 . 
     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 valve seat axis  84  of the outlet valve  56  is aligned with each of the fluid passage axis  42  and the valve seat axis  84  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. This one exception involves 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. 
     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 fluid passage  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 . 
     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 fluid passage  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 fluid passage 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 through the bore  83  of the valve seat  76  and along the valve seat axis  84 . During the fluid flow through the inlet valve  54  and into the pressure chamber  36 , 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 fluid passage  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 . 
     As the plunger  32  moves into the pressure chamber  36  and thus towards the fluid passage  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 fluid passage 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 fluid passage  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 . 
     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 . 
     In an exemplary embodiment, during the above-described operation of the reciprocating pump assembly  10 , the taper of each of the surfaces  44  and  92  balances the loading forces applied thereagainst. In an exemplary embodiment, the loading is distributed across the surface  44  and  92 , reducing stress concentrations. In an exemplary embodiment, the stresses in the valve seat  76 , in the vicinity of the fillet interface between the surfaces  86  and the  92 , are balanced with the stresses in the fluid cylinder  18 , in the vicinity of the round interface between the surfaces  46  and  44 . As a result, these stresses are reduced. In an exemplary embodiment, the taper of each of the surfaces  44  and  92  permits the outside diameter of the seat body  80  of the inlet valve  54  to be reduced, thereby also permitting a relative smaller service port, as well relatively smaller cross-bore diameters within the fluid cylinder  18 . In an exemplary embodiment, the taper of each of the surfaces  44  and  92  reduces the extraction force necessary to remove the valve seat  76  from the fluid passage  38 . 
     In an exemplary embodiment, as illustrated in  FIG. 4  with continuing reference to  FIGS. 1-3 , a taper angle  110  is defined by the tapered external shoulder  91  and thus the frusto-conical surface  92 . A taper angle  112  is defined by the tapered internal shoulder  43  and thus the frusto-conical surface  44 . Each of the taper angles  110  and  112  may be measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angles  110  and  112  are equal, and range from about 10 degrees to about 45 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angles  110  and  112  range from about 20 degrees to 40 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angles  110  and  112  range from about 25 to 35 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angles  110  and  112  are equal, and each of the taper angles  110  and  112  is about 30 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angles  110  and  112  are not equal. As shown in  FIG. 4 , a frusto-conical gap or region  114  may be defined between the surfaces  44  and  92 . Moreover, a radial clearance  116  is defined between the outside cylindrical surface  94  of the valve seat  76  and an inside surface  118  of the fluid cylinder  18 , the surface  118  being defined by the enlarged-diameter portion  38   a  of the fluid passage  38 . In an exemplary embodiment, the region  114  may be omitted and the surface  92  may abut the surface  44 . In an exemplary embodiment, material may be disposed in the region  114  to absorb, transfer and/or distribute loads between the surfaces  44  and  92 . 
     As shown in  FIG. 4 , at least the end portion of the body  80  opposite the enlarged-diameter portion  82  is tapered at a taper angle  120  from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  120  ranges from about 0 degrees to about 5 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  120  ranges from about 1 degree to about 4 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  120  ranges from about 1 degree to about 3 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  120  is about 2 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  120  is about 1.8 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, instead of, or in addition to the end portion of the body  80  opposite the enlarged-diameter portion  82  being tapered, the inside surface  46  of the fluid cylinder  18  is tapered at the taper angle  120 . In an exemplary embodiment, an interference fit may be formed between the body  80  and the inside surface  46 , thereby holding the valve seat  76  in place in the fluid cylinder. In several exemplary embodiments, instead of using an interference fit in the fluid passage  38 , a threaded connection, a threaded nut, and/or a snap-fit mechanism may be used to hold the valve seat  76  in place in the fluid cylinder  18 . 
     In an exemplary embodiment, during operation of the pump assembly  10  using the embodiment of the inlet valve  54  illustrated in  FIG. 4 , the surfaces  92  and  44  provide load balancing, with loading on the enlarged-diameter portion  82  of the valve seat  76  being distributed and transferred to the surface  44  of the fluid cylinder  18 , via either the pressing of the surface  92  against the surface  44  or intermediate material(s) disposed therebetween. 
     In an exemplary embodiment, as illustrated in  FIG. 5  with continuing reference to  FIGS. 1-4 , a fillet surface  122  of the fluid cylinder  18  is defined by the enlarged-diameter portion  38   a  of the fluid passage  38 . The fillet surface  122  extends between the frusto-conical surface  44  and the inside surface  118 . As shown in  FIG. 5 , each of the frusto-conical surfaces  92  and  44  is tapered at a taper angle  123 , which may be measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  123  ranges from about 10 degrees to about 45 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  123  ranges from about greater than 10 degrees to about 30 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  123  ranges from about 12 degrees to about 20 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the taper angle  123  is about 14 degrees measured from the fluid passage axis  42  and the valve seat axis  84  aligned therewith. In an exemplary embodiment, the surface  92  and  44  may be tapered at respective angles that are not equal. The surface  92  abuts the surface  44 . As shown in  FIG. 5 , the groove  90  and the o-ring  88  are omitted in favor of an annular groove  124  and an o-ring  126 , respectively. The annular groove  124  is formed in the frusto-conical surface  92 , and the o-ring  126  is disposed in the annular groove  124 . The o-ring  126  sealingly engages the frusto-conical surface  44 . 
     In an exemplary embodiment, during operation of the pump assembly  10  using the embodiment of the inlet valve  54  illustrated in  FIG. 5 , loads applied to the valve seat  76  are distributed and transferred to the fluid cylinder  18  via, at least in part, the load balancing provided by the abutment of the surface  92  against the surface  44 . 
     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 fluid passage  42  are applied against the top of the valve body  100 . This loading is usually greatest as the plunger  32  moves towards the fluid passage  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 fluid passage  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  of the fluid cylinder  18  via either the engagement of the surface  92  against the surface  44  or intermediate material(s) disposed therebetween. The tapering of the surfaces  92  and  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 . 
     In an exemplary embodiment, as illustrated in  FIGS. 6-8  with continuing reference to  FIGS. 1-5 , an inlet valve is generally referred to by the reference numeral  128  and includes several parts that are identical to corresponding parts of the inlet valve  54 , which identical parts are given the same reference numerals. The inlet valve  128  includes a valve seat  129 . The valve seat  129  includes several features that are identical to corresponding features of the valve seat  76 , which identical features are given the same reference numerals. An annular notch  130  is formed in the valve seat  128  at the intersection of the surfaces  86  and  92 . 
     As shown in  FIG. 8 , a taper angle  132  is defined by the external tapered shoulder  93  and thus the frusto-conical surface  94 . The taper angle  132  may be measured from the valve seat axis  84 . In an exemplary embodiment, the taper angle  132  is about 30 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the taper angle  132  ranges from about 10 degrees to about 45 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the taper angle  132  ranges from about 20 degrees to about 40 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the taper angle  132  ranges from about 25 to about 35 degrees measured from the valve seat axis  84 . The cylindrical surface  94  defined by the enlarged-diameter portion  82  of the valve seat  129  defines an outside diameter  134 . In an exemplary embodiment, the outside diameter  134  is about 5 inches. In an exemplary embodiment, the outside diameter  134  is about 5.06 inches. The inside surface  85  of the seat body  80  defined by the bore  83  formed therethrough defines an inside diameter  136 . In an exemplary embodiment, the inside diameter  136  ranges from about 3 inches to about 3.5 inches. In an exemplary embodiment, the inside diameter  136  is about 3.27 inches. An annular surface  138  of the seat body  80  is defined by the annular groove  90 . A groove diameter  140  is defined by the annular surface  138 . In an exemplary embodiment, the groove diameter  140  ranges from about 4 inches to about 4.5 inches. In an exemplary embodiment, the groove diameter  140  is about 4.292 inches. In an exemplary embodiment, an outside diameter  142  is defined by the outside surface  86  of the seat body  80  at an axial location therealong adjacent the annular notch  130 , or at least in the vicinity of the intersection between the surfaces  86  and  92 . In an exemplary embodiment, the outside diameter  142  ranges from about 4 inches to about 5 inches. In an exemplary embodiment, the outside diameter  142  ranges from about 4.5 inches to about 5 inches. In an exemplary embodiment, the outside diameter  142  ranges from about 4.5 inches to about 4.6 inches. In an exemplary embodiment, the outside diameter  142  is about 4.565 inches. The outside surface  86  is tapered radially inward beginning at the axial location of the outside diameter  142  and ending at the end of the body  80  opposite the enlarged-diameter portion  82 , thereby defining a taper angle  144  from the valve seat axis  84 . In an exemplary embodiment, the taper angle  144  ranges from about 0 degrees to about 5 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the taper angle  144  ranges from greater than 0 degrees to about 5 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the taper angle  120  is about 2 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the taper angle  144  is about 1.8 degrees measured from the valve seat axis  84 . 
     In an exemplary embodiment, as illustrated in  FIG. 9  with continuing reference to  FIGS. 1-8 , the inlet valve  54  is omitted from the pump assembly  10  in favor of the inlet valve  128 , which is disposed in the fluid passage  38 . The tapered external shoulder  91  of the valve seat  129  engages the tapered internal shoulder  43  of the fluid cylinder  18 . Thus, the frusto-conical surface  92  engages the frusto-conical surface  44 . In an exemplary embodiment, the tapered internal shoulder  43  defines a taper angle from the fluid passage axis  42  that is equal to the taper angle  132 . In an exemplary embodiment, the tapered internal shoulder  43  defines a taper angle that is equal to the taper angle  132 , and the taper angle  132  ranges from about 10 degrees to about 45 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the tapered angle  132  ranges from about 20 degrees to 45 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the tapered angle  132  ranges from about 25 degrees to 35 degrees measured from the valve seat axis  84 . In an exemplary embodiment, the tapered internal shoulder  43  defines a taper angle that is equal to the taper angle  132 , and the taper angle  132  is about 30 degrees measured from the valve seat axis  84 . The o-ring  88  sealingly engages the inside surface  46  of the fluid cylinder  18 . The outside surface  86  of the body  80  of the valve seat  129  of the inlet valve  128  engages the inside surface  46  of the fluid cylinder  18 . In an exemplary embodiment, at least the reduced-diameter portion  38   a  of the fluid passage  38  is tapered such that an inside diameter  146  defined by the portion  38   a  decreases along the fluid passage  42  in an axial direction away from the enlarged-diameter portion  38   a.  In an exemplary embodiment, at an axial location corresponding to the intersection between the surfaces  46  and  44 , the inside diameter  146  ranges from about 4 inches to about 5 inches. In an exemplary embodiment, at an axial location corresponding to the intersection between the surfaces  46  and  44 , the inside diameter  146  ranges from about 4.5 inches to about 5 inches. In an exemplary embodiment, at an axial location corresponding to the intersection between the surfaces  46  and  44 , the inside diameter  146  ranges from about 4.5 inches to about 4.6 inches. In an exemplary embodiment, at an axial location corresponding to the intersection between the surfaces  46  and  44 , the inside diameter  146  is about 4.553 inches. In an exemplary embodiment, an interference fit is formed between the outside surface  86  and the inside surface  46 , thereby preventing the valve seat  129  from being dislodged from the fluid passage  38 . 
     In an exemplary embodiment, the operation of the inlet valve  129  during the operation of the pump assembly  10  is identical to the operation of the inlet valve  54 . Therefore, the operation of the inlet valve  129  during the operation of the pump assembly  10  will not be described in detail. 
     In an exemplary embodiment, the inlet valve  54  may be omitted from the pump assembly  10  in favor of the inlet valve  128 , and the outlet valve  56  may be omitted from the pump assembly  10  in favor of an outlet valve that is identical to the inlet valve  128 . In an exemplary embodiment, the operation of the pump assembly  10  using the inlet valve  128 , and an outlet valve that is identical to the inlet valve  128 , is identical to the above-described operation of the pump assembly  10  using the inlet valve  54  and the outlet valve  56 . 
     In several experimental exemplary embodiments, experimental finite element analyses were conducted on an Experimental Baseline Embodiment (simulating a previous pump assembly that may be referred to as Legacy or the Legacy model) of a combination of the valve seat  129  and the fluid cylinder  18 , and also on three Experimental Exemplary Embodiments of combinations of the valve seat  129  and the fluid cylinder  18 . Experimental stresses were determined at three points in each of the Experimental Exemplary Embodiments 1, 2 and 3, which points are shown in  FIG. 9 , namely Point A, which is on the fluid cylinder  18  at about the intersection between the surfaces  44  and  118 ; Point B, which is on the valve seat  129  at about the nadir defined by the annular notch  130 ; and Point C, which is on the valve seat  129  at about the intersection between the axially-extending surface of the fluid cylinder  18  defined by the annular groove  90  and the lower radially-extending surface of the fluid cylinder  18  defined by the annular groove  90 . 
     For the Experimental Baseline Embodiment, the taper angle  132  was 90 degrees, the inside diameter  136  was 3.27 inches, and the outside diameter  134  was 5.06 inches. For Experimental Exemplary Embodiments 1, 2 and 3, the taper angle  132  was 30 degrees, the inside diameter  136  was 3.27 inches, and the outside diameter  134  was 5.06 inches. These values correspond to the plunger  32  being a 4.5-inch plunger, that is, the plunger  32  having an outside diameter of about 4.5 inches. Additional dimensions of the Experimental Exemplary Embodiments are set forth in Table I below (these values also correspond to the plunger  32  being a 4.5-inch plunger): 
     
       
         
           
               
             
               
                 TABLE I 
               
             
            
               
                   
               
               
                 Dimensions 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Experimental 
                 Experimental 
                 Experimental 
                 Experimental 
               
               
                   
                 Baseline 
                 Exemplary 
                 Exemplary 
                 Exemplary 
               
               
                   
                 Embodiment 
                 Embodiment 1 
                 Embodiment 2 
                 Embodiment 3 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Inside diameter 
                 4.641 
                 4.641 
                 4.596 
                 4.553 
               
               
                 146 (inches) 
               
               
                 Groove diameter 
                 4.380 
                 4.380 
                 4.335 
                 4.292 
               
               
                 140 (inches) 
               
               
                 Outside diameter 
                 4.653 
                 4.653 
                 4.608 
                 4.565 
               
               
                 142 (inches) 
               
               
                   
               
            
           
         
       
     
     The stress response results of the experimental finite element analyses, under a simulated condition corresponding to the pressure chamber  36  being pressurized at 16,800 psi, are set forth in Table II below: 
     
       
         
           
               
             
               
                 TABLE II 
               
             
            
               
                   
               
               
                 Stress Responses at 16,800 psi 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Experimental 
                 Experimental 
                 Experimental 
                 Experimental 
               
               
                   
                 Baseline 
                 Exemplary 
                 Exemplary 
                 Exemplary 
               
               
                   
                 Embodiment 
                 Embodiment 1 
                 Embodiment 2 
                 Embodiment 3 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Von-mises stress - Point 
                 58,632.6 
                 41,860.4 
                 41,754.2 
                 41,658.5 
               
               
                 A (psi) 
               
               
                 Von-mises stress - Point 
                 106,517 
                 59,282.6 
                 58,571.6 
                 58,312.3 
               
               
                 B (psi) 
               
               
                 Von-mises stress - Point 
                 52,330 
                 81,584.5 
                 81,849.1 
                 81,216.9 
               
               
                 C (psi) 
               
               
                 1st principal stress - Point 
                 49,716.1 
                 26,393.5 
                 26,148.7 
                 25,944.3 
               
               
                 A (psi) 
               
               
                 1st principal stress - Point 
                 86,958.5 
                 22,320.2 
                 20,384.6 
                 19,046.2 
               
               
                 B (psi) 
               
               
                   
               
            
           
         
       
     
     The stress response results of the experimental finite element analyses, under a simulated condition corresponding to the pressure chamber  36  being pressurized at 19,286 psi, are set forth in Table III below: 
     
       
         
           
               
             
               
                 TABLE III 
               
             
            
               
                   
               
               
                 Stress Responses at 19,286 psi 
               
            
           
           
               
               
               
               
               
            
               
                   
                 Experimental 
                 Experimental 
                 Experimental 
                 Experimental 
               
               
                   
                 Baseline 
                 Exemplary 
                 Exemplary 
                 Exemplary 
               
               
                   
                 Embodiment 
                 Embodiment 1 
                 Embodiment 2 
                 Embodiment 3 
               
               
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 Von-mises stress - Point 
                 69,340.0 
                 47,815.8 
                 47,697.2 
                 47,591.5 
               
               
                 A (psi) 
               
               
                 Von-mises stress - Point 
                 123,150 
                 77,791.6 
                 76,387.5 
                 75,565.0 
               
               
                 B (psi) 
               
               
                 Von-mises stress - Point 
                 50,763 
                 76,511.0 
                 77,434.2 
                 77,433.5 
               
               
                 C (psi) 
               
               
                 1st principal stress - Point 
                 59,885.5 
                 29,796.5 
                 29,546.8 
                 29,340.3 
               
               
                 A (psi) 
               
               
                 1st principal stress - Point 
                 110,138 
                 42,530.0 
                 39,977.6 
                 38,101.2 
               
               
                 B (psi) 
               
               
                   
               
            
           
         
       
     
     As indicated in Tables II and III above, as the experimental outside diameter  142  of the experimental valve seat  129  was reduced, the experimental stress responses decreased. This was an unexpected result. The decreases in experimental stress responses for Points B and A on the Experimental Exemplary Embodiments of the valve seat  129  were unexpected because it was expected that, as the cross-sectional area of the valve seat  129  (corresponding to a cross-section of the body  80  that is below the enlarged-diameter portion  82  and is perpendicular to the valve seat axis  84 ) decreased, the stress responses at Points B and A would increase. Unexpected experimental results were achieved with the taper angle  132  being about 30 degrees, the outside diameter  134  being about 5 inches, the inside diameter  136  being about 3 inches, the groove diameter being about 4 inches, and, unexpectedly, the outside diameter  142  being less than 4.6 inches. Based on these unexpected results, it was determined that a new pump assembly  10  could be produced based on the pump assembly  10 , with the diameters  146 ,  140  and  142  of the new pump assembly  10  being sufficiently less than the diameters  146 ,  140  and  142  of the previous pump assembly  10  so that the valve seat  129  of the new pump assembly  10  would not be operationally compatible with the fluid cylinder  18  of the previous pump assembly  10 , and so that the valve seat  129  of the previous pump assembly  10  would not be operationally compatible with the fluid cylinder  18  of the new pump assembly  10 , thereby preventing any mix-up of parts between the new and previous pump assemblies  10 . These goals of operational incompatibility and long-term mix-up prevention could be achieved while unexpectedly improving the stress responses of the new pump assembly  10 . 
     In an exemplary embodiment, as illustrated in  FIG. 10  with continuing reference to  FIGS. 1-9 , a method of producing a new pump assembly based on the previous pump assembly is generally referred to by the reference numeral  150  and referred to herein as Legacy or the Legacy model. The method  150  includes a step  152  at which a replacement fluid cylinder is produced, the replacement fluid cylinder including a replacement fluid passage formed therein, the replacement fluid passage defining a replacement inside diameter. The step  152  includes sizing the replacement inside diameter so that a valve seat sized and shaped for the Legacy pump assembly is not permitted to be disposed in the replacement fluid passage. Since the Legacy valve seat is not permitted to be disposed in the replacement fluid passage, the parts are operationally incompatible and a mix-up of the parts is avoided. At step  154 , a replacement valve seat is produced, the replacement valve seat defining a replacement outside diameter. The step  154  includes sizing the replacement outside diameter so that the replacement outside diameter is less than a Legacy inside diameter defined by a Legacy fluid passage formed in a Legacy fluid cylinder of the Legacy model pump assembly, and so that a radial clearance is defined between the replacement valve seat and an inside surface of the Legacy fluid cylinder defined by the Legacy fluid passage if the replacement valve seat is disposed in the Legacy fluid passage. As a result, if the replacement valve seat is disposed in the Legacy fluid passage and the Legacy pump assembly is subsequently operated, the Legacy pump assembly will not be able to hold pressure and this pressure deficiency will be quickly and easily detected, prompting troubleshooting and the detection of the operational incompatibility, and mix-up, of the parts. Thus, a long-term mix-up of the parts is avoided. At step  156 , the replacement valve seat is disposed in the replacement fluid passage of the replacement fluid cylinder. In several exemplary embodiments, the method  150  includes additional steps in which the replacement pump assembly is assembled in accordance with the foregoing description of the pump assembly  10 . In several exemplary embodiments, each of the replacement and Legacy fluid cylinders may be identical to the fluid cylinder  18  as illustrated in  FIG. 9 , and each of the replacement and Legacy valve seats may be identical to the valve seat  129  as illustrated in  FIGS. 8 and 9 , with at least two exceptions. First, the inside diameter  146  of the replacement fluid cylinder is less than the outside diameter  142  of the Legacy valve seat so that the Legacy valve seat is not permitted to be disposed in the portion  38   a  of the fluid passage  38  of the replacement fluid cylinder. Second, the outside diameter  142  of the replacement valve seat is less than the inside diameter  146  of the Legacy fluid cylinder so that a radial clearance is defined between the surface  86  of the replacement valve seat and the inside surface  46  of the Legacy fluid cylinder. 
     In an exemplary embodiment, as illustrated in  FIG. 11  with continuing reference to  FIGS. 1-10 , a valve seat is generally referred to by the reference numeral  160  and includes several features that are identical to corresponding features of the valve seat  129 , which identical features are given the same reference numerals. The annular notch  130  of the valve seat  129  is omitted in favor of an annular channel  162 . In an exemplary embodiment, the taper angle  132  is about 30 degrees measured from the axis  84 . In an exemplary embodiment, the outside diameter  134  is about 4.5 inches. In an exemplary embodiment, the inside diameter  136  is about 3 inches. In an exemplary embodiment, the groove diameter  140  is about 3.5 inches. In an exemplary embodiment, the outside diameter  142  is about 3.5 inches. In an exemplary embodiment, the taper angle  144  is about 1.8 degrees measured from the axis  84 . In an exemplary embodiment, the taper angle  132  ranges from about 10 degrees to about 45 degrees measured from the axis  84 . In an exemplary embodiment, the outside diameter  134  ranges from about 4 inches to about 5 inches. In an exemplary embodiment, the inside diameter  136  ranges from about 2.5 inches to about 3.5 inches. In an exemplary embodiment, the groove diameter  140  ranges from about 3 inches to about 4 inches. In an exemplary embodiment, the outside diameter  142  ranges from about 3 inches to about 4 inches. In an exemplary embodiment, the taper angle  144  ranges from greater than 0 degrees to about 5 degrees. In several exemplary embodiments, the valve seat  129  may be used in one or more of the valves  54 ,  56  and  128 . 
     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 ,  56  and  128  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 ,  56  and  128  or the components thereof, such as the valve seats  76 ,  129  and  160 , 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. 
     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. 
     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. 
     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. 
     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.