FIG. 5, but at a different cross section that passes through a recess 170′ defined by a surface 190 formed by the valve body 152′. The recess 170′ intersects the valve body bore 154′ so that a spring 172′ can be mounted in the recess 170′ at a fixed end and sized to extend from the recess 170′ to pressingly engage against an outer conical surface 108′ of the insert 106′. Like described above, this technology transfers the wear from the valve body bore 154′ to the less complex and less expensive insert 106′.

Returning momentarily to FIG. 5 that depicts the plug valve 150 constructed in accordance with embodiments of this technology. The skilled artisan having read this description understands that this technology transfers the erosion wear from the bore of the body 152 to the outer conical surface of the insert 151. As described, leakage can occur because the free end of the seal 158 abrades away the outer conical surface of the insert 151. In some illustrative embodiments the repair procedure can entail resurfacing the insert 151 to provide a new sealing surface for the seal 158 mounted in the body 152. Alternatively, the insert 151 can simply be replaced with a new one.

In yet other alternative embodiments a disposable wear member can be provided between the outer conical surface of the insert 151 and the bore of the body 152. For purposes of this description and the claims the disposable wear member can be a disposable liner (not depicted) with one surface facing the bore of the body 152 to function effectively the same as the outer conical surface of the insert 151. In some embodiments an opposing inner surface of the liner can mate directly to the outer conical surface of the insert 151. Alternatively, a seal can be provided between the inner surface of the liner and the outer conical surface of the insert. That seal can be mounted to the insert and extending to seal against a sealing surface formed by the liner (such as by using the insert 106 in FIG. 1), or the seal can be mounted to the inner surface of the liner and extending to seal against a sealing surface formed by the outer surface of the insert.

Turning to another type of flow device that is well-suited for practicing this technology, FIG. 9 is a simplified isometric cross-sectional depiction of a hydraulic fracturing fluid end 200 that is constructed in accordance with previously attempted solutions. The fluid end 200 is generally a manifold 201 used to deliver highly-pressurized corrosive and/or abrasive fluids, typically used in hydraulic fracturing processes in the oil and gas industry. Fluid may pass through the fluid end 200 at pressures that range from 5,000-15,000 pounds per square inch (psi). Fluid ends 200 used in high pressure hydraulic fracturing operations typically move fluid at a minimum of 8,000 psi. However, normally, the fluid end 200 will move fluid at pressures around 10,000-15,000 psi.

The manifold body or housing 201 typically has a first conduit 220 and a second conduit 221 formed within the body 201 that intersect to form an internal chamber 222. The first conduit 220 is typically orthogonal to the second conduit 221. The first conduit 220 may have aligned first and second sections 223 and 224 that are situated on opposite sides of the internal chamber 222. Likewise, the second conduit 221 may have aligned third and fourth sections 225 and 226 that are situated on opposite sides of the internal chamber 222. The sections 223, 224, 225, and 226 each may independently interconnect the internal chamber 222 to an external surface 227 of the fluid end 200.

A plunger 228 reciprocates within the body 201 to increase the pressure of fluid being discharged from the fluid end 200. As shown in FIG. 9, the plunger 228 may be disposed within the third section 225 of the second conduit 221. The plunger 228 is powered by an engine operatively engaged with the fluid end 200. In high pressure hydraulic fracturing operations, the engine preferably has a power output of at least 2,250 horsepower. Valve seats 229 are also shown within the first conduit 220. The valve seats 229 may support valves, such as a ball valve, used to control the movement of high pressure fluid within the body 201.

There are sealing areas in the fluid end 200 that experience the kind of erosion issues described above in plug valves. Similar to the conventional plug valve 100 depicted in FIG. 1, a number of components seal to the manifold body 201. Here, again, the sacrificial member for erosion, by design, is the body 201 instead of the less complex and less expensive mating component.

For example, the body 201 defines a discharge opening 202 that opens into the first conduit 220. The discharge opening 202 depicted in these embodiments is sealed closed by inserting a closure or discharge plug or cover 204 into the conduit 220 and securing it by advancing a retaining nut 206 into the body 201. The discharge plug 204 supports a seal 208 that seals against the bore defining the discharge opening 202. FIG. 10 is a simplified cross-sectional depiction of the discharge plug 204 that has a surface 205 defining a recess 207 into which the seal 208 is mounted at an inner radial surface 211 of the radial seal 208.

In these illustrative embodiments the recess 207 is rectangular but the contemplated embodiments are not so limited. The skilled artisan understands that the configuration of the recess 207 is largely determined by what shape is required to mount the type of seal selected. The recess 207 intersects an outer surface 215 of the discharge plug 204, permitting the seal 208 to be sized so that a portion not mounted within the recess 207 extends beyond the outer surface 215 to pressingly engage against the bore 209 defining the discharge opening 202. In this construction the highly-pressurized corrosive and/or abrasive fluid can harsh fluid can be injected between the seal 208 and the bore 209, causing erosion of the seal surface formed by the bore 209. This technology transfers that erosion wear from the body bore 209 to the less complex and less expensive discharge plug 204.

Fluid end bodies have conventionally been made of heat-treated carbon steel, so it was not uncommon for the body 201 to crack before any sacrificial erosion of the body progressed to the point of creating leakage between the discharge plug 204 and the bore 209. However, progress in the technology has introduced stainless steel body construction resulting in a significantly longer operating life. As a result, this erosion is no longer negligible but is instead a consideration for reducing erosion in modern fluid end construction. One leading source of bore 209 erosion in conventional fluid ends is the seal 208 mounted in the discharge plug 204 and extending therefrom to seal against a sealing surface formed by the body 201.

FIG. 11 is an exploded cross-sectional depiction of a fluid end 230 that is constructed in accordance with this technology to, in numerous places, transfer the erosion wear from the body to the less complex and less expensive component that is sealed to the body. A manifold body 232 forms a number of interconnected bores or conduits, including a first conduit or discharge bore 234 forming a discharge opening 235 that is similar to the discharge opening 202 in the conventional fluid end 200 depicted in FIG. 9. The discharge bore 234 further defines an intake opening 231 formed opposite the discharge opening 235. The term “discharge bore” for purposes of this description means the surface defining the discharge opening 235 into which a closure or discharge plug 236 and a retaining nut 238 are installed, and the surface defining the intake opening 231. For clarity, although FIG. 11 references the discharge bore 234 as defining an upper end of the discharge opening 235 where the retaining nut 238 attaches, the discharge bore 234 also references lower portions of the discharge opening 235 where the discharge plug 236 seals to the body 232 and where the valve seat (not depicted) seals to the body 232. Likewise, the discharge bore 234 also references upper portions of the intake opening 231. Generally, for purposes of this description the discharge bore 234 forms multi-dimensional diameters at different longitudinal locations of the discharge opening 235 and intake opening 231.

The discharge opening 235 is sealed closed by inserting the discharge plug 236 into the discharge opening 235 and securing it in place by advancing the retaining nut 238. Unlike the conventional plug 204 in FIG. 9, however, the plug 236 does not have a seal mounted to it that seals against the bore 234. Instead, the plug 236 defines a sealing surface 237 for a seal (not depicted in FIG. 11) that is mounted in an endless groove or recess formed by a surface 239 of the body 232. The sealing surface 237 is axially spaced between a first surface 251 and an opposite second surface 253 of the plug 236.

FIG. 12 is a simplified cross-sectional enlargement depicting the construction of the seal positioned within the surface 239 of the body 232. The surface 239 forms an endless groove or recess 240 that intersects the discharge bore 234. A seal 242 in these illustrative embodiments is mounted in the recess 240 to include an outer radial surface, and is thereby supported by the body 232. The recess 240 is characterized by a pair of parallel sidewalls joined by a base. The recess 240 opens towards a centerline of the conduit within which it is formed. Alternatively, as shown by recess 266 in FIGS. 14-15, the recess may open in a direction parallel to a centerline of the conduit within which it is formed. As above, the rectangular-groove shape of the recess 240 is merely illustrative and not limiting of the contemplated embodiments. Any shape necessary to properly mount a desired seal is contemplated, whether the seal is elastomeric, spring, metal, and the like. As above, the recess 240 intersects the bore 234 permitting the seal 242 to be sized so that a portion of the seal 242 not contained in the recess 240 extends beyond the recess 240 and beyond the bore 234 to pressingly seal against the sealing surface 237 (FIG. 11) defined by the discharge plug 236.

This seal construction depicted in FIG. 12 transfers the erosion wear from the body to the discharge plug. That significantly improves fluid end operations because repairs involving the discharge plug 236 are significantly less complex and less expensive than repairs involving the body 232, which typically involve weld-repair. Furthermore, weld-repairing the body 232 makes it susceptible to premature fatigue cracking in the repaired area. Further, even more operating life can be achieved by applying an erosion-resistant surface treatment to the plug 236, such as a high velocity oxygen fuel (HVOF) treatment, a tungsten carbide coating, material carburizing, and the like. Replacing instead of repairing an eroded discharge plug 236 is typically feasible, making it advantageously possible to repair a leaking valve constructed according to this technology in the field and thereby significantly reducing down time.

Returning to FIG. 11, the body 232 has a surface 241 defining an endless groove or recess intersecting the bore 234 and configured to mount a seal (not depicted) that extends from the recess to seal against a sealing surface formed by a discharge valve seat (not depicted). Similarly, the body 232 has a surface 243 forming another endless groove or recess intersecting the bore 234 and configured to mount another seal (not depicted) that is sized to extend from the recess to seal against a sealing surface formed by a suction valve seat (not depicted). The multiple references to a same bore 234 is for purposes of ease of description and is not narrowing of the contemplated embodiments of this technology. Whether the recesses defined by surfaces 241, 243 are formed in the same bore or different bores does not alter the scope of the contemplated embodiments directed to the recess for mounting the seal is formed in the body, and a seal is mounted in the recess and from there seals against a sealing surface of a component in a sealing engagement therebetween.

Similarly, a suction bore 247 is sealed closed by inserting a closure or suction plug or cover 244 defining a sealing surface 245 and securing it in place by advancing a retaining nut 246 in the body 232. Like the plug 236, the sealing surface 245 is axially spaced between a first surface 255 and an opposite second surface 261 of the plug 244. Again, the body 232 in these illustrative embodiments has a surface 248 forming an endless groove or recess intersecting the bore 247 and configured for mounting a seal (not depicted) extending from the recess and sealing against the sealing surface 245 of the suction plug 244. That transfers the wear from the body 232 to the suction plug 244 in comparison to previously attempted solutions and in accordance with the embodiments of this technology.

The body 232 also forms a plunger opening 250 sized to closely receive a stuffing box sleeve 254 that is sealed in place by advancing a retaining nut 256. The stuffing box sleeve 254 is characterized by a tubular sleeve. The plunger 228, shown in FIG. 9, may be disposed within the stuffing box sleeve 254.

The opening 250 is formed in part by the plunger bore 252 having a surface 257 defining an endless groove or recess intersecting the bore 252, into which a seal (not depicted) is mounted in these illustrative embodiments. The suction bore 247 and the plunger bore