Patent Application
20240271614
The present disclosure relates generally to well service pumps, and more particularly to fatigue resistant power end frames for hydraulic fracturing pumps.
Hydraulic fracturing pumps, also referred to as “frac pumps”, are commonly used in oilfield operations to supply pressurized fluid downhole. Hydraulic fracturing pumps are typically constructed as multi-cylinder reciprocating pumps with a power end and a fluid end. The power end comprises the driving assembly that operates piston plungers to reciprocate into and out of the cylinders of the fluid end of the pump.
A pump power end frame provides a fatigue-resistant crankshaft housing machined from a one-piece forging. The crankshaft housing may include machined features and/or bolted-on accessories. The crankshaft housing and the accessories have no welds that are subject to cracking in response to cyclic stresses due to operation of the pump.
The details of one or more implementations of the pump power end frame of the present disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the implementations will be apparent from the description and drawings.
For a more complete understanding of this disclosure and its features, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
Like reference symbols in the various drawings indicate like elements.
A hydraulic fracturing pump may be a multi-cylinder reciprocating pump with a power end and a fluid end. The power end drives piston plungers reciprocating into and out of cylinders in the fluid end. As a result, fluid is drawn into the cylinders of the fluid end through a suction manifold and then discharged under pressure through a discharge outlet of the fluid end.
The power end of a well service pump operates by rotating a crankshaft that drives connecting rods in a reciprocating fashion. Each of the connecting rods is coupled to a crosshead that linearly drives a pony rod. The pony rods are connected to piston plungers that reciprocate into and out of cylinders in the fluid end.
The moving components of the power end are housed within a power end frame. Conventional power end frames are formed by welding together multiple plates and other components in various configurations. Other conventional power end frames may be formed from a one-piece casting or a one-piece casting with additional pieces welded to it.
Due to industry demands, well service pumps are exposed to increasingly more severe operating conditions (pressures, temperatures and flow rates). As such, well service pumps can experience significant cyclic stresses during operation. Over time, these cyclic stresses tend to promote fatigue failure in power end frames since weldments and castings are poorly adapted for fatigue applications. For example, welds can have quality issues that promote cracking, welds can be very difficult to inspect, and it is difficult to perform accurate fatigue analysis on welded structures. Castings are porous and can be brittle, thus increasing the chances of cracking during cyclic loading.
The present disclosure is directed to a power end frame with a crankshaft housing formed of a one-piece forging that is better suited for fatigue applications than conventional power end frames. The power end frame further comprises a crosshead section formed of a traditional welded structure, but held in compression by a plurality of long threaded fasteners, referred to herein as stayrods, such that the crosshead section does not experience the same fatigue issues found in conventional power end frames.
Referring now to the drawings, where like reference numerals represent like components,
Power end 10 comprises a crankshaft portion 100, a crosshead portion 200 and a spacer portion 300. A frame 20 of the power end 10 comprises a crankshaft housing 110, a crosshead housing 210 and a spacer housing 310 coupled together by a plurality of upper stayrods 322 and a plurality of lower stayrods 324.
Within the frame 20, a crankshaft 120 is positioned with the crankshaft housing 110 supported by crankshaft bearings 125, and a plurality of connecting rods 130 are coupled to the crankshaft 120 to extend between the crankshaft housing 110 and the crosshead housing 210. A plurality of crossheads 230 each couple to a corresponding one of the plurality of connecting rods 130, and the plurality of crossheads 230 are positioned within the crosshead housing 210. A plurality of pony rods 330 each couple to a corresponding one of the plurality of crossheads 230 to extend between the crosshead housing 210 and the spacer housing 310. The spacer housing 310 further comprises a plurality of openings 340 through which a plurality of fluid end piston plungers (not shown) extend. Each of the fluid end piston plungers couples to a corresponding one of the plurality of pony rods 330.
As previously described, the power end 10 operates by rotating the crankshaft 120 to drive the connecting rods 130 in a reciprocating fashion. Each of the connecting rods 130 is coupled to a corresponding crosshead 230 that linearly drives a pony rod 330. The pony rods 330 are connected to fluid end piston plungers (not shown) that reciprocate through the openings 340 in the spacer housing 310, into and out of cylinders in the fluid end.
The crankshaft housing 110 further comprises simple machined features, such as threaded openings, mounting holes, apertures, and windows, for example, upon which accurate fatigue analysis can be performed. In some implementations, the front side of the crankshaft housing 110 may include machined apertures 156 through which the connecting rods 130 extend. The back side of the crankshaft housing 110 may include corresponding machined windows 158 to provide access to the interior of the crankshaft housing 110 for maintenance, troubleshooting and assembly.
Referring again to
Referring again to
The crosshead housing 210 further comprises a plurality of lubricant pass through holes 226 corresponding to the lubricant pass through holes 166 on the front of the crankshaft housing 110 to enable passing of lubricant from the crosshead housing 210 to the crankshaft housing 110. The crosshead housing 210 also includes a plurality of upper ports 222 through which the plurality of upper stayrods 322 extend and a plurality of lower ports 224 through which the plurality of lower stayrods 324 extend.
Referring now to
In various implementations, the additional accessories may include upper stayrod adapters 182 with male ends that thread into the upper threaded openings 152 in the crankshaft housing 110, and lower stayrod adapters 184 with male ends that thread into the lower threaded openings 154 in the crankshaft housing 110. The stayrod adapters 182, 184 further include female ends into which the stayrods 322, 324 thread. In conventional power end frames, the stayrods are received directly into threaded openings in the crankshaft housing, or another portion of the power end frame, and such stayrods occasionally break off inside these threaded openings. This stayrod breakage can require major repairs to, or even replacement of, the crankshaft housing or other portions of the power end frame. In contrast, the stayrod adapters 182, 184 of the present disclosure can simply be removed from the crankshaft housing 110 in the event that a stayrod breaks off inside one of these stayrod adapters 182, 184.
As shown in
In some implementations, the curved rear cover 178 is formed of aluminum and a gasket is provided between the cover 178 and the crankshaft housing 110. In some implementations, the mounting leg 179, 179′ is formed of a single piece of steel in a substantially or fully rounded shape that acts like a spring to relieve stress on the power end frame 20 during operation.
Thus, the crankshaft housing 110 is adapted to resist fatigue failure. The crankshaft housing 110 is machined from a one-piece forging, it includes machined features upon which accurate fatigue analysis can be performed, and all additional accessories are bolted to the crankshaft housing 110. As a result, the crankshaft housing 110 itself and the additional accessories have no welds that are subject to cracking in response to cyclic stresses due to operation of the hydraulic fracturing pump.
It is to be understood the implementations are not limited to particular systems or processes described which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular implementations only, and is not intended to be limiting. As used in this specification, the singular forms “a”, “an” and “the” include plural referents unless the content clearly indicates otherwise. As another example, “coupling” includes direct and/or indirect coupling of members.
Although the present disclosure has been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the disclosure as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present disclosure. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 63/440,810 filed Jan. 24, 2023 and entitled “Pump Power End Frame”, which is incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63440810 | Jan 2023 | US |
