INTEGRATED MOTOR AND PUMP ASSEMBLY

Abstract

A pump assembly that includes a crankshaft having main journals and crankpin journals, rods operatively coupled with the crankpin journals, reciprocating members operatively coupled with the rods, and an electric motor operable to rotate the crankshaft. The electric motor includes a stator and a rotor. The rotor is directly connected with the crankshaft and is operable to rotate the crankshaft to move the plurality of rods and reciprocating members to move a fluid.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. Provisional Application No. 61/973,065 entitled “Integrated Electric Motor Power-end for Reciprocating Pumps,” filed Mar. 31, 2014, the entire disclosure of which is hereby incorporated herein by reference.

Background of the Disclosure

In oilfield operations, reciprocating pumps are utilized at wellsites for large scale, high-pressure operations. Such operations may include drilling, cementing, acidizing, water jet cutting, and hydraulic fracturing of subterranean formations. In some applications, several pumps may be connected in parallel to a single manifold, flow line, or well. Some reciprocating pumps include reciprocating members driven by a crankshaft toward and away from a fluid chamber to alternatingly draw in, pressurize, and expel fluid from the fluid chamber. Hydraulic fracturing of a subterranean formation, for example, may utilize fluid at a pressure exceeding 10,000 PSI.

The success of pumping operations can be affected by many factors of the pumps, including physical size, weight, energy efficiency, and ability to collectively control individual pumps operating at the wellsite. Reciprocating pumps may have a large physical size and weight to satisfy intended fluid flow rates during oilfield operations. Accordingly, one or more pumps may be mounted on a truck or a skid for transportation to the wellsite. However, due to their size and/or weight, a limited number of pumps may be mounted on a single truck or skid. The pumps may also include a diesel engine or an asynchronous AC electric motor as part of a power section of the pump driving a fluid section of the pump. However, diesel engines and some asynchronous AC electric motors operate at high speeds, such as 1500 to 2000 revolutions per minute (RPM), and the fluid section of the pump operates at low speeds, such as 300 to 400 RPM, a gear box, chain case, or other transmission is included in the power section to operatively couple the engine/motor with the crankshaft. This also increases the size, weight, and cost of the pump(s). Moreover, each engine is individually fueled and controlled, which limits flexibility and control over a collective pumping system when multiple pumps are being operated simultaneously.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify indispensable features of the claimed subject matter, nor is it intended for use as an aid in limiting the scope of the claimed subject matter.

The present disclosure introduces an apparatus that includes a pump assembly. The pump assembly includes a drive shaft, rods operatively coupled with the drive shaft, reciprocating members each operatively coupled with a corresponding one of the rods, and an electric motor operable to rotate the drive shaft. The electric motor includes a rotor having a rotor shaft. The rotor shaft is connected with the drive shaft and is operable to rotate the drive shaft and thus move the rods and reciprocating members. The rotor shaft and the drive shaft rotate at the same speed. The reciprocating members are operable to move a fluid.

The present disclosure also introduces an apparatus that includes a pump assembly having a crankshaft. The crankshaft includes main journals and crankpin journals. The pump assembly also includes rods each operatively coupled with a corresponding one of the crankpin journals, reciprocating members each operatively coupled with a corresponding one of the rods, and an electric motor operable to rotate the crankshaft. The electric motor includes a stator and a rotor. The rotor is directly connected with the crankshaft and is operable to rotate the crankshaft and thus move the rods, thereby causing the plurality of reciprocating members to move a fluid.

The present disclosure also introduces a method that includes connecting a fluid source to a pump assembly. The pump assembly includes a drive shaft, rods operatively coupled with the drive shaft, reciprocating members operatively coupled with the rods, and an electric motor that includes a stator and a rotor that is directly connected with the drive shaft. The method also includes operating the electric motor to rotate the rotor and the drive shaft at the same speed such that the rotating drive shaft moves the rods and reciprocating members to pump the fluid from the fluid source through the pump assembly.

These and additional aspects of the present disclosure are set forth in the description that follows, and/or may be learned by a person having ordinary skill in the art by reading the materials herein and/or practicing the principles described herein. At least some aspects of the present disclosure may be achieved via means recited in the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a schematic view of at least a portion of apparatus according to one or more aspects of the present disclosure.

FIG. 2 is a perspective view of a portion of an example implementation of the apparatus shown in FIG. 1 according to one or more aspects of the present disclosure.

FIG. 3 is a side sectional view of a portion of an example implementation of the apparatus shown in FIG. 1 according to one or more aspects of the present disclosure.

FIG. 4 is a top partial sectional view of a portion of an example implementation of the apparatus shown in FIG. 3 according to one or more aspects of the present disclosure.

FIG. 5 is a side sectional view of a portion of an example implementation of the apparatus shown in FIG. 1 according to one or more aspects of the present disclosure.

FIG. 6 is a top partial sectional view of a portion of an example implementation of the apparatus shown in FIG. 5 according to one or more aspects of the present disclosure.

FIG. 7 is a top partial sectional view of a portion of an example implementation of the apparatus shown in FIG. 1 according to one or more aspects of the present disclosure.

FIG. 8 is a top partial sectional view of a portion of an example implementation of the apparatus shown in FIG. 1 according to one or more aspects of the present disclosure.

FIG. 9 is a schematic view of a portion of an example implementation of the apparatus shown in FIG. 1 according to one or more aspects of the present disclosure.

FIG. 10 is a flow-chart diagram of at least a portion of a method according to one or more aspects of the present disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for simplicity and clarity, and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.

FIG. 1 is a schematic view of at least a portion of an example pumping system 100 according to one or more aspects of the present disclosure. The figure depicts a wellsite surface 102 adjacent to a wellbore 104 and a partial sectional view of a subterranean formation 106 penetrated by the wellbore 104 below the wellsite surface 102. The pumping system 100 may comprise a first mixer 108 fluidly connected with one or more tanks 110 and a first container 112. The first container 112 may contain a first material and the tanks 110 may contain a liquid. The first material may be or comprise a hydratable material or gelling agent, such as guar, a polymer, a synthetic polymer, a galactomannan, a polysaccharide, a cellulose, and/or a clay, among other examples, and the liquid may be or comprise an aqueous fluid, which may comprise water or an aqueous solution comprising water, among other examples. The first mixer 108 may be operable to receive the first material and the liquid, as indicated by arrows 114, 116, and mix or otherwise combine the first material and the liquid to form a base fluid. The base fluid may be or comprise that which is known in the art as a gel. The first mixer 108 may then discharge the base fluid, as indicated by arrow 118.

The first mixer 108 and the first container 112 may each be disposed on corresponding trucks, trailers, and/or other mobile carriers 120, 122, respectively, such as may permit their transportation to the wellsite surface 102. However, the first mixer 108 and/or the first container 112 may be skidded or otherwise stationary, and/or may be temporarily or permanently installed at the wellsite surface 102.

The pumping system 100 may further comprise a second mixer 124 fluidly connected with the first mixer 108 and a second container 126. The second container 126 may contain a second material that may be substantially different than the first material. For example, the second material may be or comprise a proppant material, such as may comprise sand, sand-like particles, silica, quartz, and/or propping agents, among other examples.

The second mixer 124 may be operable to receive the base fluid from the first mixer 108, as indicated by arrow 118, and the second material from the second container 126, as indicated by arrow 128, and mix or otherwise combine the base fluid and the second material to form a mixture. The mixture may be or comprise that which is known in the art as a fracturing fluid. The second mixer 124 may then discharge the mixture, as indicated by arrow 130.

The second mixer 124 and the second container 126 may each be disposed on corresponding trucks, trailers, and/or other mobile carriers 132, 134, respectively, such as may permit their transportation to the wellsite surface 102. However, the second mixer 124 and/or the second container 126 may be skidded or otherwise stationary, and/or may be temporarily or permanently installed at the wellsite surface 102.

The mixture may be communicated from the second mixer 124 to a common manifold 136, as indicated by arrow 130. The manifold 136 may comprise a plurality of valves, diverters, and/or other fluid pathways 150 operable to direct the mixture in a predetermined and/or selective manner. The manifold 136, which may be known in the art as a missile or a missile trailer, may distribute the mixture to one or more pump assemblies 200. Each pump assembly 200 may receive the mixture from the manifold 136 or another conduit, as indicated by arrows 138, and discharge the mixture to the manifold 136 or another conduit, as indicated by arrows 140. The mixture may then be discharged from the manifold 136 into the wellbore 104, as indicated by arrow 142, perhaps through various valves, conduits, and/or other hydraulic circuitry fluidly connected between the manifold 136 and the wellbore 104.

The pump assemblies 200 may each be mounted on corresponding trucks, trailers, and/or other mobile carriers 144, such as may permit their transportation to the wellsite surface 102. However, the pump assemblies 200 may be skidded or otherwise stationary, and/or may be temporarily or permanently installed at the wellsite surface 102. Although each mobile carrier 144 is shown carrying three pump assemblies 200, other quantities of pump assemblies 200 are within the scope of the present disclosure. For example, each mobile carrier 144 may carry one, two, four, or more pump assemblies 200.

The pumping system 100 may also comprise a control center 146 and a source of electric power 148, such as may be collectively utilized as a centralized power distribution system operable to control and/or provide electric power to one or more portions of the pumping system 100. The source of electric power 148 may be or comprise an engine-generator set, such as a gas turbine generator, an internal combustion engine generator, or other sources of electrical power known in the art. Electric power and/or control signals may be communicated between the control center 146, the source of electric power 148, and other wellsite equipment via electrical conductors 152 extending therebetween. However, other means of communication, such as wireless communication, is also within the scope of the present disclosure.

The control center 146 may be utilized to control at least a portion of the pumping system 100 during pumping operations, including the mixers 108, 124 and the pump assemblies 200. For example, the control center 146 may be operable to control the production rate of the mixture, such as by increasing or decreasing the flow of the liquid from the tanks 110, the first material from the first container 112, the base fluid from the first mixer 108, the second material from the second container 126, and/or the mixture from the second mixer 124. The control center 146 may also be operable to control the speed of individual electrical motors 250, shown in FIGS. 3-9, such as may be operable to control the speed of the pump assemblies 200 and, therefore, the output flow rate of each pump assembly 200. The control center 146 may comprise one or more variable speed drives (VSD) (not shown), which may facilitate speed control of the electric motors 250. In other implementations of the pumping system 100, the one or more VSDs may be disposed adjacent to or in association with each pump assembly 200 or a fleet of pump assemblies 200. The control center 146 may also be operable to control the output pressure of the mixture or other fluid discharged from each of the pump assemblies 200.

Furthermore, the control center 146 may be operable to pair the valves of the manifold 136 with the pump assemblies 200 to create an interlock between the pump assemblies 200 and the manifold 136. The control center 146 may also be operable to fluidly connect and disconnect predetermined pump assemblies 200 from the internal fluid pathways 150 through the manifold 136. The control center 146 may also be operable to control power distribution between the source of electric power 148 and the first mixer 108, the second mixer 124, the pump assemblies 200, and other pumps and/or conveyers (not shown).

The control center 146 and the source of electric power 148 may be disposed on a corresponding truck, trailer, and/or other mobile carrier 154, 156, such as may permit its transportation to the wellsite surface 102. However, the control center 146 and the source of electric power 148 may be skidded or otherwise stationary, and/or may be temporarily or permanently installed at the wellsite surface 102.

FIG. 2 is a perspective view of an example implementation of the pump assembly 200 shown in FIG. 1 according to one or more aspects of the present disclosure. FIG. 3 is a side sectional view of a portion of the pump assembly 200 shown in FIG. 2. The following description refers to FIGS. 2 and 3, collectively.

The pump assembly 200 may be or comprise a reciprocating pump assembly having a power section 202 and a fluid section 210. The fluid section 210 may comprise a pump housing 216 having a plurality of fluid chambers 218 extending therethrough in a substantially parallel configuration. One end of each fluid chamber 218 may be plugged by a cover plate 220, which may be threadedly engaged with the pump housing 216. The opposite end of each chamber 218 may contain a reciprocating member 222 slidably disposed therein. Although the reciprocating member 222 is depicted as a plunger, the reciprocating member 222 may be implemented as a piston, diaphragm, or another reciprocating member.

Each fluid chamber 218 may be fluidly connected with a corresponding fluid inlet cavity 224 adapted for communicating the fluid into each fluid chamber 218 from a fluid inlet conduit 226. Each fluid inlet cavity 224 may contain an inlet valve 228, which may be operable to control the flow of fluid from the fluid inlet conduit 226 to the fluid chamber 218. Each inlet valve 228 may be biased toward a closed position by a first spring 230, which may be held in place by an inlet valve stop 232. Each inlet valve 228 may be actuated to an open position by a selected or predetermined differential pressure between the fluid inlet cavity 224 and the fluid inlet conduit 226. The fluid inlet conduit 226 may be fluidly connected with a low pressure fluid outlet (not shown) of the manifold 136 or another fluid conduit for supplying the mixture or another fluid to be pumped by the pump assembly 200.

Each fluid chamber 218 may also be fluidly connected with a fluid outlet cavity 234 extending through the pump housing 216, such as may be adapted for communicating pressurized fluid from each fluid chamber 218 into one or more fluid outlet conduits 235. The fluid outlet cavity 234 may contain therein a plurality of outlet valves 236, which may be operable to control fluid flow out of the fluid chambers 218 into the fluid outlet cavity 234. The outlet valves 236 may be biased toward a closed position by a second spring 238, which may be held in place by an outlet valve stop 240. The outlet valve 236 may be actuated to an open position by a predetermined differential pressure between the fluid chamber 218 and the fluid outlet cavity 234. The fluid outlet cavity 234 may be plugged by a plurality of second cover plates 242, which may be threadedly engaged with the pump housing 216, while one or both ends of the fluid outlet cavity 234 may be fluidly coupled with the one or more fluid outlet conduits 235. The fluid outlet conduits 235 may be fluidly connected to a high-pressure inlet (not shown) of the manifold 136 or another destination for the pressurized mixture or fluid.

During pumping operations, portions of the power section 202 of the pump assembly 200 may rotate to generate a reciprocating linear force, such as may move the reciprocating members 222 longitudinally within the corresponding fluid chambers 218. With regard to each reciprocating member 222, as the reciprocating member 222 moves out of the fluid chamber 218, as indicated by arrow 221, the pressure of the fluid inside the fluid chamber 218 decreases, thus creating a differential pressure across the fluid inlet valve 228, which actuates the fluid inlet valve 228 to permit the mixture or other fluid from the fluid inlet conduit 226 to enter the fluid inlet cavity 224 and the fluid chamber 218. The fluid then enters the fluid chamber 218 as the reciprocating member 222 continues to move longitudinally out of the fluid chamber 218 until the pressure difference between the fluid inside the fluid chamber 218 and the fluid within the fluid inlet conduit 226 is low enough, thus permitting the first spring 230 to actuate the fluid inlet valve 228 to the closed position. As the reciprocating member 222 begins to move longitudinally back into the fluid chamber 218, as indicated by arrow 223, the pressure of the fluid inside of fluid chamber 218 begins to increase. The fluid pressure inside the fluid chamber 218 continues to increase as the reciprocating member 222 continues to move into the fluid chamber 218 until the pressure difference between the fluid inside the fluid chamber 218 and the fluid inside the fluid outlet cavity 234 is high enough to compress the second spring 238, thus actuating the fluid outlet valve 236 to the open position and permitting the pressurized fluid to move into the fluid outlet cavity 234 and the fluid outlet conduit 235. Thereafter, the fluid may be communicated to the manifold 136, as depicted in FIG. 1, or to another destination for pressurized mixture or fluid.

The fluid flow rate generated by the pump assembly 200 may depend on the physical size of the reciprocating members 222 and fluid chambers 218, as well as the speed or rate at which the reciprocating members 222 move within the fluid chambers 218. The speed or rate at which the reciprocating members 222 move is directly related to the rotational speed of the power section 202, such that the fluid flow rate may be controlled by the rotational speed of the power section 202.

The power section 202 of the pump assembly 200 may also comprise a power section housing 254 enclosing an electric motor 250, which may be disposed about a drive shaft 252. The electric motor 250 is operable to drive or otherwise rotate the drive shaft 252. The electric motor 250 may comprise a motor housing 255 enclosing a stator 256 and a rotor 258. The stator 256 may be or comprise a plurality of field coils or windings, such as may generate a magnetic field when powered by electric current from the source of electric power 148 or another source of electric power. The stator 256 may define an axial opening containing the rotor 258 and through which the drive shaft 252 extends. The rotor 258 may comprise a plurality of windings or permanent magnets 259 fixedly disposed about a rotor shaft 260. The rotor shaft 260 may be a hollow shaft or comprise an axial bore 261 through which the drive shaft 252 extends. The rotor shaft 260 or another portion of the rotor 258 may be directly and/or otherwise fixedly coupled with the drive shaft 252, such that the rotor shaft 260 may transmit torque from the rotor 258 directly to the drive shaft 252. Thus, because the rotor shaft 260 and the drive shaft 252 are directly and/or otherwise fixedly coupled, the rotor shaft 260 and the drive shaft 252 may rotate at the same speed or rate. The electric motors 250 utilized within the scope of the present disclosure may include, for example, synchronous and asynchronous electric motors, such as may be operable to rotate at selected speeds between zero and about 500 RPM, although other speeds are also within the scope of the present disclosure. For example, the electric motors 250 may rotate at speeds between about 300 RPM and about 400 RPM.

The directly and/or otherwise fixedly coupled relationship between the rotor shaft 260 and the drive shaft 252 may be interpreted to include an implementation of the pump assembly 200 in which the rotor shaft 260 and the drive shaft 252 are in direct contact with each other, thus preventing relative rotation between the rotor shaft 260 and the drive shaft 252 such that the rotor shaft 260 and the drive shaft 252 rotate at the same speed or rate. The directly and/or otherwise fixedly coupled relationship between the rotor shaft 260 and the drive shaft 252 may also be interpreted to include an implementation of the pump assembly 200 in which the rotor shaft 260 and the drive shaft 252 are not in direct contact, but are connected by one or more rigid intervening members collectively fixedly connecting the rotor shaft 260 and the drive shaft 252 together, such as a ring (not shown), in a manner preventing relative rotation between the rotor shaft 260 and the drive shaft 252 such that the rotor shaft 260 and the drive shaft 252 rotate at the same speed or rate. However, the directly and/or otherwise fixedly coupled relationship between the rotor shaft 260 and the drive shaft 252 is not intended to be interpreted to include implementations in which rotation of the drive shaft 252 is facilitated by a transmission, gearbox, gear train, or other similar mechanism operatively connecting the rotor shaft 260 and the drive shaft 252.

FIG. 4 is a top partial sectional view of a portion of an example implementation of the pump assembly 200 shown in FIG. 3 according to one or more aspects of the present disclosure. Referring to FIGS. 3 and 4, collectively, the drive shaft 252 may be implemented as a crankshaft comprising a plurality of support journals 262, main journals 264, and crankpin journals 266. The support and main journals 262, 264 may extend along a central axis of rotation 268 of the drive shaft 252, while the crankpin journals 266 may be offset from the central axis of rotation 268 by a predetermined distance and spaced 120 degrees apart with respect to the support journals 262 and main journals 264.

FIG. 4 shows an example implementation of the pump assembly 200 comprising two electric motors 250 disposed about the drive shaft 252. As shown, the rotor shaft 260 of each motor 250 may be disposed about and directly and/or otherwise fixedly connected with two of the main journals 264, such as may facilitate transfer of torque from the motors 250 directly to the drive shaft 252 to rotate the drive shaft 252 when the motors are powered. To prevent relative rotation between the power section housing 254 and the motors 250, the power section housing 254 and motor housing 255 may be fixedly coupled together. Although the example implementation of the pump assembly 200 shown in FIG. 4 comprises two electric motors 250, it is to be understood that other quantities of electric motors 250 may be incorporated as part of the pump assembly 200. For example, a drive shaft 252 comprising six main journals 264 may comprise one, two, three, four, or more electric motors 250, which are connected with and/or distributed between the six main journals 264.

When two or more separate electric motors 250 are utilized to rotate the drive shaft 252, the electrical motors 250 may need to be synchronized to run at the same speed by synchronizing the VSDs, such as during ramp up, ramp down, and steady speed motor conditions. Torque limits may also be set on the VSDs to limit and/or prevent twisting or deformation of the drive shaft 252, such as when the electric motors 250 are not synchronized.

The drive shaft 252 and the rotor shaft 260 may be directly and/or otherwise fixedly coupled by corresponding threads, set screws, retaining rings, interlocking splines, interlocking keys, interference/press fit, adhesives, and/or other means operable to lock the drive shaft 252 and the rotor shaft 260 together and/or prevent their relative rotation. However, in other implementations of the pump assembly 200, the drive shaft 252 and the rotor shaft 260 may instead be integrally formed as a single discrete member operable to move as a single unit. For the electric motors 250 to be mounted about the main journals 264, each motor 250 may comprise a width (i.e., length along the central axis 268) that may permit mounting between adjacent crankpin journals 266. However, one or more of the main journals 264 may comprise a width that may permit mounting of a wider electric motor 250 between the adjacent crankpin journals 266.

In still other implementations of the pump assembly 200, the drive shaft 252 may comprise a plurality of discrete and/or otherwise separable portions adapted to be interconnected. For example, the main journals 264 and the crankpin journals 266 may comprise discrete and/or separable members, which may be coupled together to form the drive shaft 252. These separable main journals 264 and crankpin journals 266 may be fixedly coupled by corresponding threads, bolts, set screws, retaining rings, interlocking splines, interlocking keys, interference/press fit, adhesives, and/or other means operable to couple the separable main journals 264 and crankpin journals 266 together and prevent their relative rotation. Furthermore, the rotor shafts 260 of the electric motor 250 may be or comprise solid members (i.e., not comprising the central bore), which may also be or serve as the separable main journals 264, such as may be operable to fixedly couple with the separable crankpin journals 266 to form the drive shaft 252. Such configuration may permit piece-by-piece or modular assembly and/or construction of the drive shaft and/or the power section 202 of the pump assembly 200.

As depicted in FIG. 4, the main journals 264 may comprise an outer diameter that is substantially the same or slightly smaller than the diameter of the axial bore 261 of the rotor shaft 260, such as may facilitate direct and/or otherwise fixed connection between the main journals 264 and the rotor shaft 260. However, the electric motor 250 may be configured such that the axial bore 261 extending through the rotor shaft 260 may comprise an inner diameter that is greater than the maximum outer diameter of the drive shaft 252, or be adapted to simultaneously enclose the three crankpin journals 266, thus permitting the drive shaft 252 to be translated axially therethrough, such as during assembly and/or maintenance. In such implementations, the inner diameter of the bore 261 may be substantially the same or similar to that of a stator axial opening 316 shown in FIGS. 5 and 6, and the intermediate member (such as the ring, not shown), may be utilized to extend between and/or fixedly couple the rotor shaft 260 with the main journals 264.

The drive shaft 252 and the rotor 258 may be supported in position within the stator 256 by the power section housing 254, wherein the support journals 262 may extend through opposing openings 272 in the power section housing 254. To facilitate rotation of the drive shaft 252 within the power section housing 254, one or more bearings 270 may be disposed about the support journals 262 and against the side surfaces of the openings 272. A cover plate 274 and/or other means for protection may enclose the bearings 270.

Referring again to FIGS. 3 and 4, the power section housing 254 and the pump housing 216 may be coupled together via an intermediate housing 280. For example, the pump housing 216 may be fastened with the intermediate housing 280 by a plurality of threaded fasteners 282, and the intermediate housing 280 may be fastened with the power section housing 254 by another plurality of threaded fasteners 284. The intermediate housing 280 may further comprise an access door 298, which may facilitate access to portions of the pump assembly 200, such as during assembly and/or maintenance of the pump assembly 200.

To transform and transmit the rotational motion of the drive shaft 252 to a reciprocating linear motion of the plungers 222, a plurality of crosshead mechanisms 285, comprising a plurality of connecting members, may be utilized. For example, each crosshead mechanism 285 may comprise a connecting rod 286 pivotally coupled with a corresponding crankpin journal 266 at one end and with a pin 288 of a crosshead 290 at an opposing end. During pumping operations, inner walls of the intermediate housing 280 may guide each crosshead 290, such as may reduce or eliminate lateral motion of each crosshead 290. Each crosshead mechanism 285 may further comprise a piston rod 292 coupling the crosshead 290 with the reciprocating member 222. The piston rod 292 may be coupled with the crosshead 290 via a threaded connection 294 and with the reciprocating member 222 via a flexible connection 296.

For the electric motors 250 to be mounted about the main journals 264, each motor 250 may comprise a width that may permit mounting between adjacent connecting rods 286 rotatably coupled with adjacent crankpin journals 266. However, one or more of the main journals 264 may comprise a greater width that may permit mounting of a wider electric motor 250 between adjacent connecting rods 286. Accordingly, when the electric motors 250 are powered, the rotors 258 transfer torque to the drive shaft 252, which, in turn, actuate the reciprocating members 222 via the crosshead mechanisms 285 to cause the fluid section 210 to pump fluid from the fluid inlet conduit 226 to the fluid outlet conduit 235.

FIG. 5 is a side sectional view of a portion of another example implementation of the pump assembly 200 shown in FIG. 1, designated herein by reference numeral 300, according to one or more aspects of the present disclosure. FIG. 6 is a top partial sectional view of a portion of the pump assembly 300 shown in FIG. 5 according to one or more aspects of the present disclosure. For simplicity and clarity, components of the pump assembly 300 comprising the same or similar structure and/or function as corresponding components of the pump assembly 200 will be identified using the same numerals.

Referring to FIGS. 5 and 6, collectively, the pump assembly 300 may comprise a fluid section 210, an intermediate housing 280, and a plurality of crosshead mechanisms 285, as described above. The pump assembly 300 may further comprise a power section 302 having a power section housing 304 enclosing an electric motor 306, which may be disposed about a drive shaft 308. The electric motor 306 is operable to drive or otherwise rotate the drive shaft 308. The electric motor 306 comprises a motor housing 310 enclosing a stator 312 and a rotor assembly. The rotor assembly comprises a plurality of rotor sections or rotors 314 surrounded by the stator 312.

The stator 312 may be a single-piece or otherwise continuous member comprising one or more field coils or windings enclosed within the motor housing 310, such as may generate a magnetic field when powered by electric current from the source of electric power 148. The stator 312 includes an axial opening 316 in which the plurality of rotors 314 and the drive shaft 308 extend. The stator 314 and the motor housing 310 may further comprise a plurality of lateral openings 318 extending from the axial opening 316 to the exterior of the electric motor 306 toward the crossheads 290. The connecting rods 286 extend through the lateral openings 318 and pivotally couple the drive shaft 308 with the crossheads 290.

The rotors 314 comprise a plurality of permanent magnets 320 fixedly disposed about each rotor shaft 322 along the length of each rotor 314. The rotor shafts 322 may be hollow shafts or comprise a bore through which the drive shaft 308 extends. The rotor shafts 322 or other portion of the rotors 314 are directly and/or otherwise fixedly coupled with the drive shaft 308, such that the rotor shafts 322 transmit torque from the rotors 314 directly to the drive shaft 308. To prevent relative rotation between the power section housing 304 and the motor 306, the power section housing 304 and the motor housing 310 may be fixedly coupled together. Because the rotor shafts 322 and the drive shaft 308 are directly and/or otherwise fixedly coupled, the rotor shafts 322 and the drive shaft 308 may rotate at the same speed or rate. However, the drive shaft 308 and the rotor shafts 322 may instead be integrally formed as a single discrete member operable to move as a single unit.

FIGS. 5 and 6 show the drive shaft 308 implemented as a crankshaft comprising a plurality of support journals 324, main journals 326, and crankpin journals 328. The support and main journals 324, 326 may extend along a central axis of rotation 330 of the drive shaft 308, while the crankpin journals 328 may be offset from the central axis of rotation 330 by a predetermined distance and spaced 120 degrees apart with respect to the support journals 324 and the main journals 326. Accordingly, the axial opening 316 may comprise an inner diameter that is greater than the maximum outer diameter of the drive shaft 308, or be otherwise adapted to simultaneously enclose the crankpin journals 328, such as to permit the crankpin journals 328 and/or the rotors 314 to rotate without contacting the stator 312.

The main journals 326 and the rotor shafts 322 may be fixedly coupled, such as described above, while the crankpin journals 328 and the connecting rods 286 may be rotatably coupled, such as described above. The drive shaft 308 and the rotors 314 may be supported in position within the stator 312 by the power section housing 304 and the bearings 270, such as described above. Accordingly, when the electric motor 306 is powered, the rotors 314 transfer torque to the drive shaft 308, which, in turn, actuate the reciprocating members via the crosshead mechanisms 285 to cause the fluid section 210 to pump fluid.

FIG. 7 is a top partial sectional view of a portion of an example implementation of the pump assembly 200 shown in FIG. 1, designated herein by reference numeral 400, according to one or more aspects of the present disclosure. For simplicity and clarity, components of the pump assembly 400 comprising the same or similar structure and/or function as corresponding components of the pump assembly 200 will be identified using the same numerals.

The pump assembly 400 may comprise a fluid section 210, an intermediate housing 280, and a plurality of crosshead mechanisms 285, as described above. The pump assembly 400 may further comprise a power section 402 having a power section housing 404 partially enclosing a drive shaft 406. The pump assembly may further comprise two or more electric motors 408 coupled with opposing support journals 410 of the drive shaft 406 extending out of the power section housing 404, wherein the electric motors 408 may be operable to drive or otherwise rotate the drive shaft 406. The electric motors 408 may comprise the same or similar structure and/or function as the electric motors 250 described above, such as comprising a motor housing 255 enclosing a stator 256 and a rotor 258.

Each rotor 258 may comprise a rotor shaft 260 having a bore extending therethrough, such as may contain therein the support journals 410 or end portions of the drive shaft 406. The rotor shafts 260 or other portion of the rotors 258 are directly and/or otherwise fixedly coupled with the drive shaft 406, such that the rotor shafts 260 may transmit torque from the rotors 258 directly to the drive shaft 406. Thus, because the rotor shafts 260 and the drive shaft 406 are directly and/or fixedly coupled, the rotor shafts 260 and the drive shaft 406 may rotate at the same speed or rate. However, the drive shaft 406 and the rotor shafts 260 may instead be integrally formed as a single discrete member operable to move as a single unit. To prevent relative rotation between the power section housing 404 and the motors 408, the power section housing 404 and motor housing 255 may be fixedly coupled together or to a fixed base (not shown).

FIG. 7 shows the drive shaft 406 being implemented as a crankshaft comprising a plurality of main journals 412 and crankpin journals 414. The support and main journals 410, 412 may extend along the central axis of rotation 416 of the drive shaft 406, while the crankpin journals 414 may be offset from the central axis of rotation 416 by a predetermined distance and spaced 120 degrees apart with respect to the support journals 410 and the main journals 412.

The support journals 410 and the rotor shafts 260 may be fixedly coupled, such as described above, while the crankpin journals 414 and connecting rods 286 may be rotatably coupled, such as described above. The drive shaft 406 may be supported in position within the power section 402 by the power section housing 404 and the bearings 270, such as described above. Accordingly, when the electric motors 408 are powered, the rotors 258 transfer torque to the drive shaft 406, which, in turn, actuate the reciprocating members via the crosshead mechanisms 285 to cause the fluid section 210 to pump fluid.

The pump assembly 200 shown in FIG. 1 may be further implemented with multiple fluid sections 210, such that each pump assembly 200 may comprise a fluid section 210 on opposing sides of a centrally located power section 202, 302, 402. For example, FIG. 8 is a top partial sectional view of a portion of such an implementation of the pump assembly 200 shown in FIG. 1, designated herein by reference numeral 500, according to one or more aspects of the present disclosure. For simplicity and clarity, components of the pump assembly 500 comprising the same or similar structure and/or function as corresponding components of the pump assembly 200 will be identified using the same numerals.

The pump assembly 500 may comprise opposing fluid sections 210, intermediate housings 280, and crosshead mechanisms 285, as described above. The pump assembly 500 may further comprise a power section 502 having a power section housing 504 enclosing an electric motor 506, which may be disposed about a drive shaft 508. The electric motor 506 is operable to drive or otherwise rotate the drive shaft 508. The electric motor 506 may comprise a motor housing 510 enclosing a stator 512 and a rotor assembly. The rotor assembly comprises a plurality of rotor sections or rotors 514 surrounded by the stator 512.

The stator 512 may be a single-piece or continuous member comprising one or more field coils or windings enclosed within the motor housing 510, such as may generate a magnetic field when powered by electric current from the source of electric power 148 or another source of electric power. The stator 512 may include an axial opening 516 through which the plurality of rotors 514 and the drive shaft 508 extend. The stator 514 and the motor housing 510 may further comprise a plurality of opposing lateral openings 518 extending from the axial opening 516 to the exterior of the electric motor 506 toward the crossheads 290. The lateral openings 518 may permit the opposing connecting rods 286 to extend therethrough and pivotally couple the drive shaft 508 with the crossheads 290.

The rotors 514 comprise a plurality of permanent magnets 520 fixedly disposed about the rotor shafts 522. Each rotor shaft 522 may be a hollow shaft or comprise a bore through which the drive shaft 508 extends. The rotor shafts 522 or other portion of the rotors 514 may be directly and/or otherwise fixedly coupled with the drive shaft 508, such that the rotor shafts 522 transmit torque from the rotors 514 directly to the drive shaft 508. To prevent relative rotation between the power section housing 504 and the motor 506, the power section housing 504 and motor housing 510 may be fixedly coupled together. Because the rotor shafts 522 and the drive shaft 508 are directly and/or otherwise fixedly coupled, the rotor shafts 522 and the drive shaft 508 rotate at the same speed or rate. However, the drive shaft 508 and the rotor shafts 522 may instead be integrally formed as a single discrete member operable to move as a single unit.

FIG. 8 shows the drive shaft 508 implemented as a crankshaft comprising a plurality of support journals 524, main journals 526, and crankpin journals 528. The support and main journals 524, 526 may extend along the central axis of rotation 530 of the drive shaft 508, while the crankpin journals 528 may be offset from the central axis of rotation 530 by a predetermined distance and spaced 120 degrees apart with respect to the support journals 524 and the main journals 526. Accordingly, the axial opening 516 may comprise an inner diameter that is greater than the maximum outer diameter of the drive shaft 508, or be adapted to simultaneously enclose the crankpin journals 528, such as to permit the crankpin journals 528 and/or the rotors 514 to rotate without contacting the stator 512.

The main journals 526 and the rotor shafts 522 may be fixedly coupled, such as described above, while the crankpin journals 528 and the connecting rods 286 may be rotatably coupled, such as may permit each connecting rod 286 to pivot independently of the opposing connecting rod 286. The drive shaft 508 and the rotors 514 may be supported in position within the stator 512 by the power section housing 504 and bearings 270, such as described above. Accordingly, when the electric motor 506 is powered, the rotors 514 may transfer torque directly to the drive shaft 508, which, in turn, may actuate the reciprocating members via the crosshead mechanisms 285 to cause the opposing fluid sections 210 to pump fluid.

FIG. 8 shows the pump assembly 500 comprising two fluid sections 210 connected with a single power section 502. The power section 502 may comprise a similar structure and/or function as the power section 302 described above. However, it should be understood that other implementations of the pump assemblies 200, 300, 400, 500 comprising multiple fluid sections 210 connected with a single power section (comprising the same or similar structure and/or function as the power sections 202, 402 described above) are also within the scope of the present disclosure.

Although FIG. 8 shows two fluid sections 210 connected to a single power section 502 and spaced 180 degrees apart with respect to the central axis of rotation 530, in other implementations, the pump assembly 500 may comprise additional fluid sections 210 connected to a single centrally-located power section 502. For example, the pump assembly 500 may comprise three fluid sections 210, each connected to the centrally-located power section 502 in the same or similar manner as showed in FIG. 8 and spaced 120 degrees apart with respect to the central axis of rotation 530. In another implementation, the pump assembly 500 may comprise four fluid sections 210, each connected to the centrally-located power section 502 in the same or similar manner as shown in FIG. 8 and spaced ninety degrees apart with respect to the central axis of rotation 530. Other implementations of the pump assembly 500 comprising additional quantities of fluid sections 210 coupled with the centrally-located power section 502 are also within the scope of the present disclosure.

Although FIGS. 2-8 show the pump assembly 200 as a triplex reciprocating pump assembly comprising three fluid chambers 218 and three reciprocating members 222, other implementations within the scope of the present disclosure may include the pump assembly 200 as or comprising a quintuplex reciprocating pump assembly comprising five fluid chambers 218 and five reciprocating members 222, or other numbers of fluid chambers 218 and reciprocating members 222. It is also noted that the electric motors 250, 306, 408, 506 described above may be or comprise liquid cooled motors, such as in implementations in which one or more water jacket configurations (not shown) may be utilized to remove heat from the electric motors during operations.

In still other implementations of the pumping system 100, two or more adjacent pump assemblies 200 within a pump fleet may be operatively coupled together, such as to help synchronize the pumps and/or facilitate torque sharing between the pump assemblies 200. For example, two or more adjacent pump assemblies 200 may comprise drive shafts 252 extending past the housing 254 or the cover plate 274. The two or more adjacent pump assemblies 200 may be positioned such that the drive shafts 252 are aligned substantially along their central axes of rotation 268 to permit the drive shafts 252 to be coupled together. The drive shafts 252 may be coupled by means known in the art, including chain couplings, jaw couplings, rigid couplings, flexible couplings, spline shafts, and universal joints, among other examples.

FIG. 9 is a schematic view of a portion of another example implementation of the pump assembly 200 shown in FIG. 1, designated herein by reference numeral 600, according to one or more aspects of the present disclosure. For simplicity and clarity, components of the pump assembly 600 comprising the same or similar structure and/or function as the corresponding components of the pump assembly 200 will be identified using the same numerals.

The pump assembly 600 may comprise a power section 602 coupled with a fluid section 604. The power section 602 may comprise a motor 250 having a motor housing 255 enclosing a stator 256 and a rotor 258. The fluid section 604 may comprise a drive shaft 606 coupled with a rotary swash plate 608, which may be coupled with a swing swash plate 610. The fluid section 604 may further comprise a plurality of cylinders 612, each defining a fluid chamber 614 therein, and a plurality of reciprocating members 616 slidably movable within the fluid chambers 614. The swing swash plate 610 may be coupled with the plurality of reciprocating members 616 by a plurality of connecting rods 618. The drive shaft 606, the rotary and swing swash plates 608, 610, the connecting rods 618, the reciprocating members 616, and the cylinders 612 may be enclosed within a fluid section housing 620. The motor housing 255 and the fluid section housing 620 may be fixedly coupled, such as may prevent relative motion therebetween during operations. The pump assembly 600 may further comprise one or more bearings 622 disposed about the drive shaft 606 and against the fluid section housing 620, such as may facilitate low friction rotation of the drive shaft 606 about a central axis of rotation 623 with respect to the fluid section housing 620. The one or more bearings 622 may further support the drive shaft 606 in position within the fluid section housing 620.

The electric motor 250 may be coupled with a portion of the drive shaft 606 extending out of the fluid section housing 620, and the electric motor 250 may be operable to drive or otherwise rotate the drive shaft 606. For example, the rotor 258 may comprise a rotor shaft 260 having an axial bore 261 through which the portion of the drive shaft 606 extending out of the fluid section housing 620 may extend. The rotor shaft 260 or other portion of the rotor 258 is directly and/or otherwise fixedly coupled with the drive shaft 606, such that the rotor shaft 260 transmits torque from the rotor 258 directly to the drive shaft 606. Because the rotor shaft 260 and the drive shaft 606 are directly and/or otherwise fixedly coupled, the rotor shaft 260 and the drive shaft 606 rotate at the same speed or rate. However, the drive shaft 606 and the rotor shaft 260 may instead be integrally formed as a single discrete member operable to move as a single unit.

During pumping operations, the rotating drive shaft 606 rotates the rotary swash plate 608, which, in turn, swings the swing swash plate 610, causing the connecting rods 618 and the reciprocating members 616 to oscillate back and forth, as indicated by arrows 624, 626. The oscillating movement of the reciprocating members 616 sequentially draws and discharges fluid into and out of the fluid chambers 614 through inlet and outlet ports 628, 630. The pressurized fluid may be communicated from the pump assembly 600 to the high-pressure inlet (not shown) of the manifold 136 or to another destination.

FIG. 10 is a flow-chart diagram of at least a portion of a method 700 according to one or more aspects of the present disclosure. The method 700 may be performed utilizing at least a portion of one or more implementations of the apparatus shown in one or more of FIGS. 1-9 and/or otherwise within the scope of the present disclosure.

The method 700 comprises connecting (710) a fluid source to a pump assembly. For example, the fluid source may be the manifold 136 shown in FIG. 1, and the pump assembly may be substantially similar to one or more of the pump assemblies 200, 300, 400, 500, 600 shown in FIGS. 1-9. Thus, the pump assembly may comprise a drive shaft, a plurality of rods operatively coupled with the drive shaft, a plurality of reciprocating members operatively coupled with a plurality of rods, and an electric motor comprising a stator and a rotor that is directly and/or otherwise fixedly coupled with the drive shaft, wherein these components are as described above. The electric motor is then operated (720) to rotate the rotor and the drive shaft at the same speed, such that the rotating drive shaft moves the plurality of rods and reciprocating members to pump the fluid from the fluid source through the pump assembly.

As described above, the electric motor may comprise an axial bore extending through the rotor, and the drive shaft may extend through the axial bore. Thus, the rotating drive shaft rotates within the axial bore. Similarly, the drive shaft may comprise a crankshaft having a plurality of crankpin journals, operatively coupled with the plurality of rods, and a plurality of main journals, connected with the rotor. The electric motor may comprise a plurality of openings extending laterally from the axial bore, and operating (720) the electric motor to rotate the rotor and the crankshaft may move the plurality of rods through the plurality of openings.

As also described above, the drive shaft may be a crankshaft, the electric motor may be a first electric motor, the stator may be a first stator, the rotor may be a first rotor, and the pump assembly may further comprise a second electric motor comprising a second stator and a second rotor, wherein the first and second electric motors may be separated by a space, and the second rotor is directly connected with the crankshaft. In such implementations, operating (720) the electric motor may comprise operating the first and second electric motors to rotate the first and second rotors and the crankshaft at the same speed, wherein the rotating crankshaft moves the plurality of rods through the space between the first and second electric motors. The method (700) may further comprise electrically connecting (730) the first and second electric motors to an electric power source, such as the electric power source 148 shown in FIG. 1. The method (700) may further comprise synchronizing (750) the speed of the first and second electric motors and monitoring (740) speed of the first and second electric motors.

In view of the entirety of the present disclosure, including the figures and the claims, a person having ordinary skill in the art should readily recognize that the present disclosure introduces an apparatus comprising: a pump assembly, comprising: a drive shaft; a plurality of rods operatively coupled with the drive shaft; a plurality of reciprocating members each operatively coupled with a corresponding one of the plurality of rods; and an electric motor operable to rotate the drive shaft, wherein the electric motor comprises a rotor having a rotor shaft, wherein the rotor shaft is connected with the drive shaft, wherein the rotor shaft is operable to rotate the drive shaft and thus move the plurality of rods and reciprocating members, wherein the rotor shaft and the drive shaft rotate at the same speed, and wherein the plurality of reciprocating members are operable to move a fluid.

The plurality of reciprocating members may comprise a plurality of pistons, plungers, or diaphragms.

The rotor may further comprise a plurality of permanent magnets.

The electric motor may rotate at speeds between about zero RPM and 500 RPM. For example, the electric motor may rotate at speeds between about 300 and 400 RPM.

The pump assembly may not comprise a transmission operatively connecting the rotor shaft and the drive shaft.

The rotor shaft and the drive shaft may be integral portions of a single discrete member.

The pump assembly may further comprise: a housing disposed about the electric motor; and a bearing disposed intermediate the drive shaft and the housing.

The pump assembly may further comprise a housing disposed about the plurality of rods and/or reciprocating members, and the electric motor may be connected with the housing.

The pump assembly may further comprise a swashplate connected with the drive shaft, and the plurality of rods may be operatively coupled with the swash plate.

The drive shaft may comprise a crankshaft, such as may comprise a plurality of main journals connected with the rotor shaft. In such implementations, the electric motor may be one of a plurality of electric motors collectively operable to rotate the crankshaft, each of the plurality of electric motors may comprise a rotor having a rotor shaft and a plurality of magnets, the rotor shaft of each of the plurality of electric motors may be connected with the crankshaft, the rotor shaft of each of the plurality of electric motors may be operable to rotate the crankshaft and thus move corresponding ones of the plurality of rods, the rotor shaft of each of the plurality of electric motors and the crankshaft may rotate at the same speed, the rotor shaft of at least one of the plurality of electric motors may comprise an axial bore extending therethrough, the crankshaft may extend though the axial bore, and at least one of the plurality of electric motors may be disposed between two or more of the plurality of rods. In implementations in which the drive shaft comprises a crankshaft, the crankshaft may comprise a plurality of crankpin journals operatively coupled with a corresponding one of the plurality of rods, the crankshaft may comprise a plurality main journals each connected with a rotor shaft of a corresponding one of the plurality of electric motors, and at least one of the plurality of electric motors may be disposed between two or more of the plurality of crankpin journals.

The rotor shaft may comprise an axial bore extending longitudinally therethrough, and the drive shaft may extend through the axial bore. In such implementations, the drive shaft may comprise a crankshaft, the crankshaft may comprise a plurality of crankpin journals operatively coupled with a corresponding one of the plurality of rods, the crankshaft may comprise a plurality of main journals connected with the rotor shaft, the electric motor may further comprise a plurality of openings extending laterally from the axial bore, and the plurality of rods and/or crankpin journals may extend into the plurality of openings.

In at least one implementation, the electric motor may be a first electric motor, the rotor may be a first rotor, the rotor shaft may be a first rotor shaft, the plurality of magnets may comprise a plurality of first magnets, the pump assembly may further comprise a second electric motor operable to rotate the drive shaft, the second electric motor may comprise a second rotor having a second rotor shaft and a plurality of second magnets, the second rotor shaft may be connected with the drive shaft, the second rotor shaft may be operable to rotate the drive shaft and thus move the plurality of rods, and the second rotor shaft and the drive shaft may rotate at the same speed. In such implementation, the first rotor shaft may comprise a first axial bore extending longitudinally therethrough, the second rotor shaft may comprise a second axial bore extending therethrough, the drive shaft may be disposed within the first and second axial bores, and at least one of the first and second electric motors may be disposed between two or more of the plurality of rods.

The present disclosure also introduces an apparatus comprising: a pump assembly, comprising: a crankshaft comprising a plurality of main journals and a plurality of crankpin journals; a plurality of rods each operatively coupled with a corresponding one of the plurality of crankpin journals; a plurality of reciprocating members each operatively coupled with a corresponding one of the plurality of rods; and an electric motor operable to rotate the crankshaft, wherein the electric motor comprises a stator and a rotor, wherein the rotor is directly connected with the crankshaft, and wherein the rotor is operable to rotate the crankshaft and thus move the plurality of rods, thereby causing the plurality of reciprocating members to move a fluid.

The plurality of reciprocating members may comprise a plurality of pistons, plungers, or diaphragms.

The rotor may further comprise a plurality of permanent magnets.

The electric motor may rotate at speeds between about zero RPM and 500 RPM. For example, the electric motor may rotate at speeds between about 300 RPM and 400 RPM.

The pump assembly may further comprise: a housing disposed about the electric motor; and a bearing disposed intermediate the crankshaft and the housing.

The pump assembly may further comprise a housing disposed about the plurality of rods and/or reciprocating members, and the electric motor may be connected with the housing.

The rotor may further comprise a rotor shaft, and the rotor shaft may be connected with the crankshaft. The rotor shaft may be connected with at least one of the plurality of main journals. The rotor shaft may comprise an axial bore extending longitudinally therethrough, and the crankshaft may extend through the axial bore. The plurality of crankpin journals may be operatively coupled with a corresponding one of the plurality of rods, the plurality of main journals may be connected with the rotor shaft, the electric motor may further comprise a plurality of openings extending laterally from the axial bore, and the plurality of rods and/or crankpin journals may extend into the plurality of openings. The pump assembly may not comprise a transmission operatively connecting the rotor shaft and the crankshaft. The rotor shaft and the crankshaft may be integral portions of a single discrete member. The crankshaft may comprise a plurality of main journals connected with the rotor shaft. The electric motor may be one of a plurality of electric motors operable to rotate the crankshaft, the rotor shaft may be operable to rotate the crankshaft and thus move the plurality of rods and reciprocating members, the rotor shaft and the crankshaft may rotate at the same speed, at least one rotor shaft may comprise an axial bore extending therethrough, the crankshaft may extend though the axial bore, and at least one of the plurality of electric motors may be disposed between two or more of the plurality of rods. The crankshaft may comprise a plurality of crankpin journals operatively coupled with a corresponding one of the plurality of rods, the crankshaft may comprise a plurality main journals connected with a corresponding rotor shaft, and at least one of the plurality of electric motors may disposed between two or more of the plurality of crankpin journals. The electric motor may be a first electric motor, the rotor may be a first rotor, the rotor shaft may be a first rotor shaft, the pump assembly may further comprise a second electric motor operable to rotate the crankshaft, the second electric motor may comprise a second rotor having a second rotor shaft, the second rotor shaft may be connected with the crankshaft, the second rotor shaft may be operable to rotate the crankshaft and thus move the plurality of rods and reciprocating members, and the second rotor shaft and the crankshaft may rotate at the same speed. The first rotor shaft may comprise a first axial bore extending longitudinally therethrough, the second rotor shaft may comprise a second axial bore extending therethrough, the crankshaft may be disposed within the first and second axial bores, and at least one of the first and second electric motors may be disposed between two or more of the plurality of rods.

The present disclosure also introduces a method comprising: connecting a fluid source to a pump assembly comprising: a drive shaft; a plurality of rods operatively coupled with the drive shaft; a plurality of reciprocating members operatively coupled with a plurality of rods; and an electric motor comprising a stator and a rotor that is directly connected with the drive shaft; and operating the electric motor to rotate the rotor and the drive shaft at the same speed such that the rotating drive shaft moves the plurality of rods and reciprocating members to pump the fluid from the fluid source through the pump assembly.

The electric motor may comprise an axial bore extending through the rotor, the drive shaft may extend through the axial bore, and the rotating drive shaft may rotate within the axial bore. The drive shaft may comprise a crankshaft, the crankshaft may comprise a plurality of crankpin journals operatively coupled with the plurality of rods, the crankshaft may comprise a plurality of main journals connected with the rotor, the electric motor may comprise a plurality of openings extending laterally from the axial bore, and operating the electric motor to rotate the rotor and the crankshaft may move the plurality of rods through the plurality of openings.

The drive shaft may be a crankshaft, the electric motor may be a first electric motor, the stator may be a first stator, the rotor may be a first rotor, the pump assembly may further comprise a second electric motor comprising a second stator and a second rotor, the first and second electric motors may be separated by a space, the second rotor may be directly connected with the crankshaft, and the method may further comprise operating the second electric motor to rotate the second rotor and the crankshaft at the same speed, wherein the rotating crankshaft may move the plurality of rods through the space between the first and second electric motors. The method may further comprise electrically connecting the first and second electric motors to an electric power source. The method may further comprise: synchronizing the speed of the first and second electric motors; and monitoring speed of the first and second electric motors. The first electric motor may comprise a first axial bore extending through the first rotor, the second electric motor may comprise a second axial bore extending through the second rotor, the crankshaft may extend through the first and second axial bores, and the rotating crankshaft may rotate within the first and second axial bores. The crankshaft may comprise a plurality of crankpin journals operatively coupled with the plurality of rods, the crankshaft may comprise a first main journal coupled with the first rotor, the crankshaft may comprise a second main journal coupled with the second rotor, and the rotating crankshaft may move at least one of the plurality of crankpin journals through the space between the first and second electric motors.

The foregoing outlines features of several embodiments so that a person having ordinary skill in the art may better understand the aspects of the present disclosure. A person having ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same functions and/or achieving the same benefits of the embodiments introduced herein. A person having ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

The Abstract at the end of this disclosure is provided to comply with 37 C.F.R. §1.72(b) to permit the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. An apparatus, comprising:

a pump assembly, comprising: a drive shaft; a plurality of rods operatively coupled with the drive shaft; a plurality of reciprocating members each operatively coupled with a corresponding one of the plurality of rods; and an electric motor operable to rotate the drive shaft, wherein the electric motor comprises a rotor having a rotor shaft, wherein the rotor shaft is connected with the drive shaft, wherein the rotor shaft is operable to rotate the drive shaft and thus move the plurality of rods and reciprocating members, wherein the rotor shaft and the drive shaft rotate at the same speed, and wherein the plurality of reciprocating members are operable to move a fluid.

2. The apparatus of claim 1 wherein the rotor further comprises a plurality of permanent magnets.

3. The apparatus of claim 1 wherein the pump assembly does not comprise a transmission operatively connecting the rotor shaft and the drive shaft.

4. The apparatus of claim 1 wherein the rotor shaft and the drive shaft are integral portions of a single discrete member.

5. The apparatus of claim 1 wherein the pump assembly further comprises a swashplate connected with the drive shaft, and wherein each of the plurality of rods is operatively coupled with the swash plate.

6. The apparatus of claim 1 wherein the drive shaft comprises a crankshaft that includes a plurality of main journals connected with the rotor shaft.

7. The apparatus of claim 1 wherein:

the drive shaft comprises a crankshaft;

the electric motor is one of a plurality of electric motors collectively operable to rotate the crankshaft;

each of the plurality of electric motors comprises a rotor having a rotor shaft and a plurality of magnets;

the rotor shaft of each of the plurality of electric motors is connected with the crankshaft;

the rotor shaft of each of the plurality of electric motors is operable to rotate the crankshaft and thus move a corresponding one of the plurality of rods;

the rotor shaft of each of the plurality of electric motors and the crankshaft rotate at the same speed;

the rotor shaft of at least one of the plurality of electric motors comprises an axial bore extending therethrough;

the crankshaft extends though the axial bore; and

at least one of the plurality of electric motors is disposed between two or more of the plurality of rods.

8. The apparatus of claim 1 wherein:

the drive shaft comprises a crankshaft;

the electric motor is one of a plurality of electric motors collectively operable to rotate the crankshaft;

the crankshaft comprises a plurality of crankpin journals each operatively coupled with a corresponding one of the plurality of rods;

the crankshaft comprises a plurality main journals each connected with a rotor shaft of a corresponding one of the plurality of electric motors; and

at least one of the plurality of electric motors is disposed between two or more of the plurality of crankpin journals.

9. The apparatus of claim 1 wherein the rotor shaft comprises an axial bore extending longitudinally therethrough, and wherein the drive shaft extends through the axial bore.

10. The apparatus of claim 1 wherein:

the electric motor is a first electric motor;

the rotor is a first rotor;

the rotor shaft is a first rotor shaft;

the plurality of magnets comprises a plurality of first magnets;

the pump assembly further comprises a second electric motor operable to rotate the drive shaft;

the second electric motor comprises a second rotor having a second rotor shaft and a plurality of second magnets;

the second rotor shaft is connected with the drive shaft;

the second rotor shaft is operable to rotate the drive shaft and thus move the plurality of rods; and

the second rotor shaft and the drive shaft rotate at the same speed.

11. The apparatus of claim 10 wherein:

the first rotor shaft comprises a first axial bore extending longitudinally therethrough;

the second rotor shaft comprises a second axial bore extending therethrough;

the drive shaft is disposed within the first and second axial bores; and

at least one of the first and second electric motors is disposed between two or more of the plurality of rods.

12. An apparatus, comprising:

a pump assembly, comprising: a crankshaft comprising a plurality of main journals and a plurality of crankpin journals; a plurality of rods each operatively coupled with a corresponding one of the plurality of crankpin journals; a plurality of reciprocating members each operatively coupled with a corresponding one of the plurality of rods; and an electric motor operable to rotate the crankshaft, wherein the electric motor comprises a stator and a rotor, wherein the rotor is directly connected with the crankshaft, and wherein the rotor is operable to rotate the crankshaft and thus move the plurality of rods, thereby causing the plurality of reciprocating members to move a fluid.

13. The apparatus of claim 12 wherein the rotor further comprises a plurality of permanent magnets.

14. The apparatus of claim 12 wherein the rotor further comprises a rotor shaft, and wherein the rotor shaft is connected with the crankshaft and at least one of the plurality of main journals.

15. The apparatus of claim 14 wherein the rotor shaft comprises an axial bore extending longitudinally therethrough, and wherein the crankshaft extends through the axial bore.

16. A method, comprising:

connecting a fluid source to a pump assembly comprising: a drive shaft; a plurality of rods operatively coupled with the drive shaft; a plurality of reciprocating members operatively coupled with the plurality of rods; and an electric motor comprising a stator and a rotor that is directly connected with the drive shaft; and

operating the electric motor to rotate the rotor and the drive shaft at the same speed such that the rotating drive shaft moves the plurality of rods and reciprocating members to pump the fluid from the fluid source through the pump assembly.

17. The method of claim 16 wherein:

the electric motor comprises an axial bore extending through the rotor;

the drive shaft extends through the axial bore;

the rotating drive shaft rotates within the axial bore;

the drive shaft comprises a crankshaft;

the crankshaft comprises a plurality of crankpin journals operatively coupled with the plurality of rods;

the crankshaft comprises a plurality of main journals connected with the rotor;

the electric motor comprises a plurality of openings extending laterally from the axial bore; and

operating the electric motor to rotate the rotor and the crankshaft moves the plurality of rods through the plurality of openings.

18. The method of claim 16 wherein:

the drive shaft is a crankshaft;

the electric motor is a first electric motor;

the stator is a first stator;

the rotor is a first rotor;

the pump assembly further comprises a second electric motor comprising a second stator and a second rotor;

the first and second electric motors are separated by a space;

the second rotor is directly connected with the crankshaft; and

the method further comprises operating the second electric motor to rotate the second rotor and the crankshaft at the same speed, wherein the rotating crankshaft moves the plurality of rods through the space between the first and second electric motors.

19. The method of claim 18 further comprising electrically connecting the first and second electric motors to an electric power source.

20. The method of claim 18 further comprising:

synchronizing the speed of the first and second electric motors; and

monitoring speed of the first and second electric motors.