Fluid end access cover locking mechanism

Abstract

A reciprocating fluid end access port plug includes an access plug body, expansion assembly and bolt. The access plug body can be shaped and sized to be received within the fluid end access port to inhibit a flow of fluid therethrough, and can define an inner end surface, an outer end surface defining an axially aligned threaded aperture, and a generally cylindrical wall extending therebetween. The expansion assembly can be configured to securely retain the access plug body in a desired plug position within the fluid end access port, and can include a locking drive member defining an aperture generally aligned with the threaded aperture of the access plug body, and a plurality of radially positioned locking segments. The bolt can have a threaded shaft configured to traverse through the aperture of the expansion assembly for threaded contact with the threaded aperture of the access plug body.

What is claimed is: 
     
         1 . A reciprocating pump fluid end access port plug, comprising:
 a generally cylindrically shaped access plug body shaped and sized to be received within an access port of a fluid end to inhibit a flow of fluid therethrough, the access plug body defining an inner end surface, an outer end surface, and a generally cylindrical wall extending therebetween, the outer end surface defining an axially aligned threaded aperture;   an expansion assembly configured to securely retain the access plug body in a desired plug position within the access port, the expansion assembly including a locking drive member defining an aperture generally aligned with the threaded aperture of the access plug body, and a plurality of radially positioned locking segments; and   a bolt having an threaded shaft configured to traverse through the aperture of the expansion assembly for threaded contact with the threaded aperture of the access plug body, wherein selective rotation of the bolt relative to the access plug body is configured to increase a threaded connection between the access plug body and threaded shaft, thereby shifting the locking drive member of the expansion assembly axially relative to the plurality of locking segments and driving the plurality of locking segments radially outward from the locking drive member into contact with an inner radius of the access port.   
     
     
         2 . The access port plug of  claim 1 , wherein the access plug body is constructed of a metallic material. 
     
     
         3 . The access port plug of  claim 1 , wherein the inner end surface of the access plug body defines a recess configured to receive a portion of a plunger of a reciprocating pump. 
     
     
         4 . The access port plug of  claim 1 , wherein the cylindrical wall of the access plug body includes one or more circumferential steps defining an axial contour of the cylindrical wall. 
     
     
         5 . The access port plug of  claim 1 , wherein the axial contour of the cylindrical wall is defined by five circumferential steps, wherein the diameter of a first circumferential step is shared by the inner end surface, a diameter of the fifth circumferential step is shared by the outer end surface, and a second, a third and a fourth circumferential step are respectively positioned between the first circumferential step and the fifth circumferential step. 
     
     
         6 . The access port plug of  claim 5 , wherein the diameter of the second circumferential step is smaller than the diameter of the first circumferential step. 
     
     
         7 . The access port plug of  claim 5 , wherein the diameter of the third circumferential step is smaller than the diameter of the second circumferential step. 
     
     
         8 . The access port plug of  claim 5 , wherein the diameter of the fourth circumferential step is larger than the diameter of the first circumferential step. 
     
     
         9 . The access port plug of  claim 5 , wherein the fifth circumferential step defines a flange configured to make abutting contact with a stepped inner diameter of the access port, thereby retaining the access plug body in a desired plug position to inhibit a flow of fluid through the access port and/or to inhibit traversal of the access plug body entirely through the access port. 
     
     
         10 . The access port plug of  claim 1 , wherein an exterior wall of the locking drive member generally has a frustoconical shape configured to serve as a wedge to force the plurality of locking segments radially outward as the locking drive member is shifted axially. 
     
     
         11 . The access port plug of  claim 1 , wherein the locking drive member further includes a tapered nose configured to guide the locking drive member into assembly with the plurality of locking segments. 
     
     
         12 . The access port plug of  claim 1 , wherein the bolt includes a head having an outer surface configured to engage with a driving tool and a flat inner surface configured to contact an outer face of the locking drive member to shift the locking drive member of the expansion assembly axially relative to the plurality of locking segments. 
     
     
         13 . The access port plug of  claim 1 , wherein the expansion assembly includes at least three locking segments. 
     
     
         14 . The access port plug of  claim 1 , wherein each of the plurality of locking segments include an inner surface shaped and sized to conform to an outer diameter of the locking drive member, and an outer surface shaped and sized to conform to an inner diameter of the access port when the access port plug is in the desired plug position within the access port. 
     
     
         15 . The access port plug of  claim 1 , wherein the outer surface of the plurality of locking segments define a taper configured to impart an axial force component upon an inner diameter of the access port to aid in the retention of the access plug body in the desired plug position within the access port. 
     
     
         16 . The access port plug of  claim 1 , wherein the outer surface of the plurality of locking segments, define a grooved locking geometric configuration shaped and sized to mate with a corresponding geometric configuration defined by the diameter of the access port to aid in the retention of the access port plug in the desired plug position within the access port. 
     
     
         17 . The access port plug of  claim 1 , wherein the outer surface of the plurality of locking segments define a concave locking geometric configuration shaped and sized to mate with a corresponding geometric configuration defined by the diameter of the access port to aid in the retention of the access port plug in the desired plug position within the access port. 
     
     
         18 . The access port plug of  claim 1 , wherein each of the plurality of locking segments define a tab configured to reside within a corresponding channel defined within the outer end surface of the access plug body, thereby coupling each of the plurality of locking segments to the access plug body to inhibit axial movement of the plurality of locking segments relative to the access plug body, while enabling radial expansion of the plurality of locking segments relative to the access plug body. 
     
     
         19 . An access port plug, comprising:
 an access plug body configured to be received within an access port of a fluid end of a reciprocating pump to inhibit a flow of fluid through the access port, the access plug body defining an inner end surface, an outer end surface, and a generally cylindrical wall including one or more circumferential steps defining an axial contour of the cylindrical wall extending therebetween, the outer end surface defining an axially aligned threaded aperture;   an expansion assembly configured to securely retain the access plug body in a desired plug position within the access port, the expansion assembly including a locking drive member defining an aperture generally aligned with the threaded aperture of the access plug body, and a plurality of radially positioned locking segments, wherein each of the plurality of locking segments define a tab configured to reside within a corresponding channel defined within the outer end surface of the access plug body, thereby coupling each of the plurality of locking segments to the access plug body to inhibit axial movement of the plurality of locking segments relative to the access plug body; and   a bolt having an threaded shaft configured to traverse through the aperture of the expansion assembly for threaded contact with the threaded aperture of the access plug body, wherein selective rotation of the bolt relative to the access plug body is configured to increase a threaded connection between the access plug body and threaded shaft, thereby shifting the locking drive member of the expansion assembly axially relative to the plurality of locking segments to cause an expansion of the plurality of locking segments radially outward from the locking drive member and into contact with an inner radius of the access port.   
     
     
         20 . A method of plugging a fluid end access port of a reciprocating pump, the method comprising:
 positioning an access port plug within the fluid end access port, the access port plug including an access plug body, an expansion assembly, and a bolt, wherein the expansion assembly includes a locking drive member and a plurality of radially positioned locking segments;   rotating the bolt relative to the expansion assembly, thereby increasing a threaded connection between the access plug body and a threaded shaft of the bolt, thereby shifting the locking drive member of the expansion assembly axially relative to the plurality of locking segments and driving the plurality of locking segments radially outward from the locking drive member into engaging contact with an inner radius of the access port, thereby securely retaining the access plug body in a desired plug position within the access port.