PUMP SYSTEM

Abstract

Aspects of the disclosure relate to pumping systems, apparatus, end related methods for longer strong lengths and reduced footprints. In one aspect, pumping systems facilitate increased horsepower generated at lower cycle rates and a lesser number of pumps. In one implementation, a pump system comprises a hydraulic power end coupled to and located in between a first fluid end and a second fluid end. The hydraulic power end comprises a hydraulic cylinder assembly having a piston, a first rod coupled to the piston and to the first fluid end, and a second rod coupled to the piston and to the second fluid end located on the opposite side.

Description

BACKGROUND

Field

Aspects of the disclosure relate to pump systems for pumping fluid into an oil and gas well.

Description of the Related Art

Pump systems, such as frac pumps, are frequently used in oil and gas operations to pump fluids at high pressures into an oil and gas well. Due to the high pressures, volumes, and flow rates of fluids that are circulated through the pump systems, numerous resources are needed to maintain the operating efficiency of the pump systems, which increases the overall costs of such oil and gas operations. In addition, the power requirements and the physical space needed to operate the pump systems at an oil and gas site significantly increases as drilling technology enables more and more oil and gas wells to be drilled at the same site, which similarly increases the overall costs of such oil and gas operations.

Therefore, there is a continuous need for new and improved pump systems.

SUMMARY

Aspects of the disclosure relate to pumping systems, apparatus, end related methods for longer strong lengths and reduced footprints. In one aspect, pumping systems facilitate increased horsepower generated at lower cycle rates and a lesser number of pumps.

In one implementation, a pump system comprises a hydraulic power end comprising a hydraulic cylinder having a hydraulic cylinder housing, and a cylinder rod assembly disposed at least partially in the hydraulic cylinder housing, the cylinder rod assembly comprising: a piston disposed in the hydraulic cylinder housing, a first rod coupled to the piston and extending from a first end of the piston and out of a first side of the hydraulic cylinder, and a second rod coupled to the piston and extending from a second end of the piston and out of a second side of the hydraulic cylinder; and a first fluid end comprising a first fluid end block disposed adjacent the first side of the hydraulic cylinder; and a second fluid end comprising a second fluid end block disposed adjacent the second side of the hydraulic cylinder.

In one implementation, a pump system comprises a hydraulic power end comprising a hydraulic cylinder having a hydraulic cylinder housing, and a cylinder rod assembly disposed at least partially in the hydraulic cylinder housing, the cylinder rod assembly comprising a piston disposed in a piston chamber of the hydraulic cylinder housing, and a hydraulic fluid circuit comprising: a first supply line coupled to the piston chamber of the hydraulic cylinder housing on a first side of the piston, a first return line coupled to the piston chamber of the hydraulic cylinder housing on the first side of the piston, a second supply line coupled to the piston chamber of the hydraulic cylinder housing on a second side of the piston, a second return line coupled to the piston chamber of the hydraulic cylinder housing on the second side of the piston, and one or more pumps coupled to supply a hydraulic fluid to the first supply line and the second supply line; and a fluid end comprising a fluid end block that receives an end of the cylinder rod assembly.

In one implementation, a pump system comprises a hydraulic power end comprising a hydraulic cylinder having a hydraulic cylinder housing, and a cylinder rod assembly disposed at least partially in the hydraulic cylinder housing, the cylinder rod assembly comprising: a piston disposed in the hydraulic cylinder housing, and a rod section coupled to the piston and extending from the piston and out of a first side of the hydraulic cylinder, wherein a first end of the rod section is coupled to the piston; and a fluid end comprising a fluid end block, wherein a second end of the rod section is received in the fluid end block.

In one implementation, a method of operating a pump system comprises supplying pressurized fluid via a first supply line into a piston chamber on a first side of a piston of a cylinder rod assembly; exhausting pressurized fluid via a second return line from the piston chamber on a second side of the piston, wherein supplying and exhausting the pressurized fluid pressurizes the first side of the piston relative to the second side of the piston to move the piston and the cylinder rod assembly in a first direction toward a first fluid end; and then supplying pressurized fluid via a second supply line into the piston chamber on the second side of the piston; exhausting pressurized fluid via a first return line from the piston chamber on the first side of the piston, wherein supplying and exhausting of pressurized fluid pressurizes the second side of the piston relative to the first side of the piston to move the piston and the cylinder rod assembly in a second direction toward a second fluid end, the second direction is opposite of the first direction.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

FIG. 1 is a schematic partial sectional view of a pump system, according to one implementation.

FIG. 2 is a schematic diagram view of a method of operating a pump system, according to one implementation

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one implementation may be beneficially utilized on other implementations without specific recitation.

DETAILED DESCRIPTION

Aspects of the disclosure relate to pumping systems, apparatus, end related methods for longer strong lengths and reduced footprints. In one aspect, pumping systems facilitate increased horsepower generated at lower cycle rates and a lesser number of pumps.

The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to welding, interference fitting, and/or fastening such as by using bolts, threaded connections, pins, and/or screws. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to integrally forming. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to direct coupling and/or indirect coupling. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include operable coupling such as electric coupling and/or fluidly coupling.

FIG. 1 is a schematic partial sectional view of a pump system 100, according to one implementation. In one embodiment, which can be combined with other embodiments, the pump system 100 is a frac or mud pump system. The pump system 100 can be transported and deployed on a truck at an oil and gas wellhead site.

The pump system 100 includes a hydraulic power end 105. The hydraulic power end 105 includes a hydraulic cylinder 104 having a hydraulic cylinder housing 106, and a cylinder rod assembly 107 disposed in a piston chamber 108 of the hydraulic cylinder housing 106. The cylinder rod assembly 107 includes a piston 109 disposed in the piston chamber 108 of the hydraulic cylinder housing 106, a first rod 110 coupled to the piston 109 and extending from a first end of the piston 109 and out of a first side 112 of the hydraulic cylinder 104, and a second rod 111 coupled to the piston 109 and extending from a second end of the piston 109 and out of a second side 113 of the hydraulic cylinder 104. The pump system 100 includes a first fluid end 115A having a first fluid end block 116A disposed on and adjacent to the first side 112 of the hydraulic cylinder 104. The first fluid end block 116A includes a discharge outlet 117A having a check valve 118A disposed therein, and a suction inlet 119A having a check valve 120A disposed therein.

The pump system 100 includes a second fluid end 115B having a second fluid end block 116B disposed on and adjacent to the second side 113 of the hydraulic cylinder 104. The second fluid end block 116B includes a discharge outlet 117B having a check valve 118B disposed therein, and a suction inlet 119B having a check valve 120B disposed therein. The piston 109, the first rod 110, and the second rod 111 are part of a plunger that is received in the first fluid end block 116A and the second fluid end block 116B. The cylinder rod assembly 107 functions as the plunger. The cylinder rod assembly 107 reciprocates in a first direction D1 toward the first fluid end block 116A and a second direction D2 toward the second fluid end block 116B. As the cylinder rod assembly 107 moves in the first direction D1, an operation fluid F1 is pumped from the suction inlet 119A and out through the discharge outlet 117A. As the cylinder rod assembly 107 moves in the second direction D2, the operation fluid F1 is pumped from the suction inlet 119B and out through the discharge outlet 117B. The operation fluid F1 is a frac fluid that is pumped into one or more wellheads.

The hydraulic cylinder 104, is a double-acting hydraulic cylinder, the piston 109 is a double-acting piston, and the cylinder rod assembly 107 is a double-acting reciprocating plunger that can pump in two directions such that a forward stroke pumps an operation fluid and a return stroke also pumps an operation fluid. The pump system 100 is a hydraulic intensifier frac pump.

The piston 109 of the cylinder rod assembly 107 is coupled to a first end 121 of the first rod 110 and a first end 123 of the second rod 111. The piston 109 functions as a sealed cap coupled to and disposed about the first end 121 and the first end 123 to enclose and seal the first end 121 and the first end 123. A second end 122 of the first rod 110 is received in the first fluid end block 116A. A second end 124 of the second rod 111 is received in the second fluid end block 116B. Each of the first rod 110 and the second rod 111 is hollow and has a respective inner bore 125, 126. The cylinder rod assembly 107 includes a cap 127 disposed adjacent the second end 122 and coupled to the first rod 110, such as by using a bolt. In one embodiment, which can be combined with other embodiments, a portion of the cap 127 extends into the inner bore 125 of the first rod 110. The cylinder rod assembly 107 includes a cap 128 disposed adjacent the second end 124 and coupled to the second rod 111, such as by using a bolt. In one embodiment, which can be combined with other embodiments, a portion of the cap 128 extends into the inner bore 126 of the second rod 111. The present disclosure contemplates that the first rod 110 and the second rod 111 can be integrally formed as a single rod that extends through the piston 109 and is coupled to the piston 109.

The hydraulic cylinder 104 includes a first cylinder cap 130 disposed at the first side 112 and coupled to the hydraulic cylinder housing 106 and a second cylinder cap 140 disposed at the second side 113 and coupled to the hydraulic cylinder housing 106. The pump system 100 includes a first packing housing 180 and a first plurality of packing seals 181 disposed between the first fluid end block 116A and the first cylinder cap 130. The first packing housing 180 and the first plurality of packing seals 181 are disposed about the first rod 110. The pump system 100 includes a second packing housing 182 and a second plurality of packing seals 183 disposed between the second fluid end block 116B and the second cylinder cap 140. The second packing housing 182 and the second plurality of packing seals 183 are disposed about the second rod 111.

A first fluid end spool 184A is coupled between the first packing housing 180 and the first fluid end block 116A. A second fluid end spool 1846 is coupled between the second packing housing 182 and the second fluid end block 116B. The respective fluid end spools 184A, 184B facilitating spacing the respective fluid ends 115A, 115B from the respective packing housings 180, 182 and the hydraulic cylinder 104. The respective fluid end spools 184A, 1846 also facilitate protecting the respective rods 110, 111.

The pump system 100 includes a hydraulic fluid circuit 150 coupled to (e.g. in fluid communication with) the hydraulic cylinder 104 of the pump system 100. The hydraulic fluid circuit 150 includes a first supply line 131 coupled to the piston chamber 108 of the hydraulic cylinder housing 106 on a first side 132 of the piston 109, and a first return line 133 coupled to the piston chamber 108 of the hydraulic cylinder housing 106 on the first side 132 of the piston 109. The hydraulic fluid circuit 150 includes a second supply line 141 coupled to the piston chamber 108 of the hydraulic cylinder housing 106 on a second side 142 of the piston 109, and a second return line 143 coupled to the piston chamber 108 of the hydraulic cylinder housing 106 on the second side 142 of the piston 109. The first supply line 131 supplies hydraulic fluid H1 to the piston chamber 108 on the first side 132 of the piston 109, and the first return line 133 exhausts the hydraulic fluid H1 out of the piston chamber 108 on the first side 132. The second supply line 141 supplies hydraulic fluid H2 to the piston chamber 108 on the second side 142 of the piston 109, and the second return line 143 exhausts the hydraulic fluid H2 out of the piston chamber on the second side 142.

The hydraulic fluid circuit 150 includes one or more reservoirs 151 (one reservoir 151 is shown) to receive the hydraulic fluid H1 from the first return line 133 and the hydraulic fluid H2 from the second return line 143. The reservoirs 151 include tanks and/or bladders. The hydraulic fluid circuit 150 includes one or more pumps (a first pump 152 and a second pump 153 are shown). The first pump 152 is coupled to supply the hydraulic fluid H1 to the first supply line 131, and the second pump 153 is coupled to supply the hydraulic fluid H2 to the second supply line 141. Each of the first pump 152 and the second pump 153 is a 1,000 horsepower pump such that the hydraulic cylinder 104 generates 2,000 horsepower in output. In one embodiment, which can be combined with other embodiments, each of the first pump 152 and the second pump 153 is an axial piston variable pump.

The hydraulic fluid circuit 150 includes a first supply valve 136 along the first supply line 131 that, when open, supplies the hydraulic fluid H1 to the piston chamber 108 on the first side 132 of the piston 109. The first supply valve 136 is disposed in the first cylinder cap 130 and within the hydraulic cylinder housing 106 of the hydraulic cylinder 104. Specifically, the first supply valve 136 is shown disposed in a fluid port 134 formed in the first cylinder cap 130 but can be positioned anywhere along the first supply line 131. The hydraulic fluid circuit 150 includes a first return valve 137 along the first return line 133 that, when open, returns the hydraulic fluid H1 from the piston chamber 108 on the first side 132 of the piston 109 to the one or more reservoirs 151. The first return valve 137 is disposed in the first cylinder cap 130 and within the hydraulic cylinder housing 106 of the hydraulic cylinder 104. Specifically, the first return valve 137 is shown disposed in a fluid port 135 formed in the first cylinder cap 130 but can be positioned anywhere along the first return line 133.

The hydraulic fluid circuit 150 includes a second supply valve 146 along the second supply line 141 that, when open, supplies the hydraulic fluid H2 to the piston chamber 108 on the second side 142 of the piston 109. The second supply valve 146 is disposed in the second cylinder cap 140 and within the hydraulic cylinder housing 106 of the hydraulic cylinder 104. Specifically, the second supply valve 146 is shown disposed in a fluid port 144 formed in the second cylinder cap 140 but can be positioned anywhere along the second supply line 141. The hydraulic fluid circuit 150 includes a second return valve 147 along the second return line 143 that, when open, returns the hydraulic fluid H2 from the piston chamber 108 on the second side 142 of the piston 109 the one or more reservoirs 151. The second return valve 147 is disposed in the second cylinder cap 140 and within the hydraulic cylinder housing 106 of the hydraulic cylinder 104. Specifically, the second return valve 147 is shown disposed in a fluid port 145 formed in the second cylinder cap 130 but can be positioned anywhere along the second return line 143.

In one embodiment, which can be combined with other embodiments, each of the first supply valve 136, the first return valve 137, the second supply valve 146, and the second return valve 147 is a pressure control valve (PCV). In one embodiment, which can be combined with other embodiments, each of the first supply valve 136, the first return valve 137, the second supply valve 146, and the second return valve 147 is a gate valve, a ball valve, a swing valve, and/or any other type of isolation valve (e.g. an on/off valve).

The first supply line 131 and the first return line 133 are disposed on the first side 132 of the piston 109. The second supply line 141 and the second return line 143 are disposed on the second side 142 of the piston 109. The first fluid end block 116A is disposed at a first distance L1 relative to an outer end of the first cylinder cap 130. The second fluid end block 1166 is disposed at a second distance L2 relative to an outer end of the second cylinder cap 140. In one embodiment, which can be combined with other embodiments, each of the first distance L1 and the second distance L2 is within a range of 32 inches to 52 inches, such as 52 inches or less.

The pump system 100 includes a controller 160 coupled to the hydraulic fluid circuit 150. The controller 160 is configured to control operations of the one or more pumps 152, 153, the first supply valve 136, the second supply valve 146, the first return valve 137, and the second return valve 147. The controller 160 is configured to open the first supply valve 136 (thereby supplying the hydraulic fluid H1 to the piston chamber 108 on the first side 132 of the piston 109) and open the second return valve 147 (thereby exhausting the hydraulic fluid H2 from the piston chamber 108 on the second side 142 of the piston 109), while closing the second supply valve 146 and the first return valve 137 to move the piston 109 in the first direction D1 toward the first fluid end block 116A. The first pump 152 is powered while the first supply valve 136 is open and the first return valve 137 is closed to pump the hydraulic fluid H1 through the first supply line 131 and through the first supply valve 136. The second pump 153 is powered while the second return valve 147 is open and the second supply valve 146 is closed to return the hydraulic fluid H2 through the second return valve 147 and through the second return line 143.

The controller 160 is configured to open the second supply valve 146 (thereby supplying the hydraulic fluid H2 to the piston chamber 108 on the second side 142 of the piston 109) and open the first return valve 137 (thereby exhausting the hydraulic fluid H1 from the piston chamber 108 on the first side 132 of the piston 109), while closing the first supply valve 136 and the second return valve 147 to move the piston 109 in the second direction D2 that is opposite of the first direction D1. The second pump 153 is powered while the second supply valve 146 is open to pump the hydraulic fluid H2 through the second supply line 141 and through the second supply valve 146. The first pump 152 is powered while the first return valve 137 is open and the first supply valve 136 is closed to return the hydraulic fluid H1 through the first return valve 137 and through the first return line 133.

Moving the piston 109 in the first direction D1 moves the first rod 110 in the first direction D1 to pump the operation fluid F1 from the suction inlet 119A and out through the discharge outlet 117A of the first fluid end block 116A. Moving the piston 109 in the second direction D2 moves the second rod 111 in the second direction D2 to pump the operation fluid F1 from the suction inlet 1196 and out through the discharge outlet 1176 of the second fluid end block 1166.

The present disclosure contemplates that one or more additional reservoirs 151 and/or one or more additional pumps 152, 153 may be used. In one embodiment, which can be combined with other embodiments, the first pump 152 is coupled to the first supply line 131 to supply the hydraulic fluid H1, a first reservoir 151 is coupled to the first return line 133 to return the hydraulic fluid H1, the second pump 153 is coupled to the second supply line 141 to supply the hydraulic fluid H2, and a second reservoir 151 is coupled to the second return line 143 to return the hydraulic fluid H2. In one example, which can be combined with other examples, the first supply line 131 is fluid separated from the second supply line 141, and the first return line 133 is fluidly separated from the second return line 143. The present disclosure contemplates that the first supply line 131 and the second supply line 141 may be fluidly connected such that the same hydraulic fluid can be supplied from the one or more reservoirs 151 and split to be the hydraulic fluid H1 and the hydraulic fluid H2. The present disclosure contemplates that the first return line 133 and the second return line 143 may be fluidly connected such that the hydraulic fluid H1 and the hydraulic fluid H2 merge together prior to returning to the one or more reservoirs 151.

The first supply valve 136, the first return valve 137, the second supply valve 146, and the second return valve 147 may be directional control valves. As described herein, the the first supply valve 136 can be disposed anywhere along the first supply line 131, the first return valve 137 can be disposed anywhere along the first return line 133, the second supply valve 146 can be disposed anywhere along the second supply line 141, and the second return valve 147 can be disposed anywhere along the second return line 143. In one embodiment, which can be combined with other embodiments, the first supply valve 136 is disposed within the first pump 152 to control fluid flow along the first supply line 131 from the one or more reservoirs 151 to the piston chamber 108, and the first return valve 137 is disposed within the first pump 152 to control fluid flow along the first return line 133 from the piston chamber 108 to the one or more reservoirs 151. In one embodiment, which can be combined with other embodiments, the second supply valve 146 is disposed within the second pump 153 to control fluid flow along the second supply line 141 from the one or more reservoirs 151 to the piston chamber 108, and the second return valve 147 is disposed within the second pump 153 to control fluid flow along the second return line 143 from the piston chamber 108 to the one or more reservoirs 151.

The present disclosure contemplates that a cooling system may be used to cool components of the hydraulic power end 105 and/or cool components of the hydraulic fluid circuit 150.

The present disclosure contemplates that existing pump systems (such as frac or mud pump systems) can be retrofitted, according to retrofitting methods, to include aspects, features, components, and/or properties of the pump system 100. Existing pump systems can be retrofitted, using aspects described herein, without replacing the existing packing housing or the existing fluid end block.

The hydraulic power end 105, the first fluid end 115A, and the second fluid and 115B are disposed in a linear arrangement. The hydraulic power end 105 need not use gears (such as a transmission system) or a crankshaft therein.

FIG. 2 is a schematic diagram view of a method 200 of operating a pump system, according to one implementation. The controller 160 described above can be configured to carry out the operations 202, 204, 206, 208, 210, and 212 of the method 200 described below. Operation 202 includes supplying pressurized fluid via a first supply line (such as through a first supply valve) into a piston chamber on a first side of a piston of a cylinder rod assembly. Operation 204 includes exhausting pressurized fluid via a second return line (such as through a second return valve) from the piston chamber on a second side of the piston. The supplying of operation 202 and the exhausting of operation 204 facilitates pressurizing the first side of the piston relative to the second side of the piston. Operation 206 includes moving the piston and the cylinder rod assembly in a first direction toward a first fluid end.

Operation 208 of the method 200 includes supplying pressurized fluid via a second supply line (such as through a second supply valve) into the piston chamber on the second side of the piston. Operation 210 includes exhausting pressurized fluid via a first return line (such as through a first return valve) from the piston chamber on the first side of the piston. The supplying of operation 208 and the exhausting of operation 210 facilitates pressurizing the second side of the piston relative to the first side of the piston. Operation 212 includes moving the piston and the cylinder rod assembly in a second direction toward a second fluid end. The second direction is opposite of the first direction. The movement of the cylinder rod assembly in the second direction reciprocates the cylinder rod assembly.

Benefits of the present disclosure include a shortened length and a shortened footprint for pump units, such as those transported and deployed on truck trailers, relative to other pump units. As an example, aspects of the present disclosure facilitate a length reduction of about 40%. Benefits of the present disclosure also include facilitating a lower stroke cycle rate (for example, less than 100 cycles per minute, such as about 40 cycles per minute) at the same horsepower or a larger horsepower relative to other pumps (such as frac pumps that can operate at 150 cycles per minute to generate a required power output). Lowering stroke cycle rates facilitate increased lifespan, decreased downtime, reliable power generation, increased efficiency, and reduced costs and maintenance.

Benefits of the present disclosure also include increased horsepower at the same footprint relative to frac pumps. Benefits of the present disclosure also facilitate using a lower number of hydraulic cylinders and a lower number of frac trucks deployed to achieve a horsepower output. As an example, a single hydraulic cylinder using aspects described herein can generate 2,000 horsepower relative to other hydraulic cylinders that generate 1,000 horsepower, and a single frac truck using aspects described herein can generate 12,000 horsepower relative to other frac trucks that generate 6,000 horsepower. As an example, a frac operation at a wellhead site using operations described herein can deploy 3 frac trucks relative to other frac operations that may use 16 or more frac trucks.

Benefits of the present disclosure also include ease of disassembly for ease of maintenance. As an example, the first rod 110 and/or the second rod 111 can be decoupled from the piston 109 and removed from the hydraulic cylinder housing 106 without needing to first remove the respective fluid end block 116A, 116B from the respective rod 110, 111.

It is contemplated that one or more of the aspects disclosed herein may be combined. Moreover, it is contemplated that one or more of these aspects may include some or all of the aforementioned benefits. As an example, aspects, features, components, and/or properties of the pump system 100 can be combined with the method 200.

It will be appreciated by those skilled in the art that the preceding embodiments are exemplary and not limiting. It is intended that all modifications, permutations, enhancements, equivalents, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the scope of the disclosure. It is therefore intended that the following appended claims may include all such modifications, permutations, enhancements, equivalents, and improvements. The disclosure also contemplates that one or more aspects of the embodiments described herein may be substituted in for one or more of the other aspects described. The scope of the disclosure is determined by the claims that follow.

Claims

1. A pump system, comprising: a hydraulic power end comprising a hydraulic cylinder having a hydraulic cylinder housing, and a cylinder rod assembly disposed at least partially in the hydraulic cylinder housing, the cylinder rod assembly comprising: a piston disposed in the hydraulic cylinder housing,a first rod coupled to the piston and extending from a first end of the piston and out of a first side of the hydraulic cylinder, anda second rod coupled to the piston and extending from a second end of the piston and out of a second side of the hydraulic cylinder; anda first fluid end comprising a first fluid end block disposed adjacent the first side of the hydraulic cylinder; anda second fluid end comprising a second fluid end block disposed adjacent the second side of the hydraulic cylinder.

2. The pump system of claim 1, wherein the piston of the cylinder rod assembly is coupled to a first end of the first rod and a first end of the second rod.

3. The pump system of claim 2, wherein the first fluid end block receives a second end of the first rod of the cylinder rod assembly.

4. The pump system of claim 3, wherein the second fluid end block receives a second end of the second rod of the cylinder rod assembly.

5. The pump system of claim 4, wherein each of the first rod and the second rod of the cylinder rod assembly is hollow.

6. A pump system, comprising: a hydraulic power end comprising a hydraulic cylinder having a hydraulic cylinder housing, and a cylinder rod assembly disposed at least partially in the hydraulic cylinder housing, the cylinder rod assembly comprising a piston disposed in a piston chamber of the hydraulic cylinder housing;a hydraulic fluid circuit comprising: a first supply line coupled to the piston chamber of the hydraulic cylinder housing on a first side of the piston,a first return line coupled to the piston chamber of the hydraulic cylinder housing on the first side of the piston,a second supply line coupled to the piston chamber of the hydraulic cylinder housing on a second side of the piston,a second return line coupled to the piston chamber of the hydraulic cylinder housing on the second side of the piston, andone or more pumps coupled to supply a hydraulic fluid to the first supply line and the second supply line;a first fluid end that receives a first end of the cylinder rod assembly; anda second fluid end that receives a second end of the cylinder rod assembly.

7. The pump system of claim 6, wherein the hydraulic fluid circuit further comprises one or more reservoirs to receive the hydraulic fluid from the first return line and the second return line.

8. The pump system of claim 7, wherein the hydraulic fluid circuit further comprises: a first supply valve along the first supply line that, when open, supplies the hydraulic fluid to the piston chamber on the first side of the piston; anda second supply valve along the second supply line that, when open, supplies the hydraulic fluid to the piston chamber on the second side of the piston.

9. The pump system of claim 8, wherein the hydraulic fluid circuit further comprises: a first return valve along the first return line that, when open, returns the hydraulic fluid from the piston chamber on the first side of the piston to the one or more reservoirs; anda second return valve along the second return line that, when open, returns the hydraulic fluid from the piston chamber on the second side of the piston to the one or more reservoirs.

10. The pump system of claim 9, wherein each of the first supply valve, the second supply valve, the first return valve, and the second return valve is disposed within the hydraulic cylinder.

11. The pump system of claim 9, further comprising a controller coupled to each of the one or more pumps, the first supply valve, the second supply valve, the first return valve, and the second return valve.

12. The pump system of claim 11, wherein the controller is configured to open the first supply valve and the second return valve while the second supply valve and the first return valve are closed to move the piston in a first direction toward the fluid end block.

13. The pump system of claim 12, wherein the controller is further configured to open the second supply valve and the first return valve while the first supply valve and the second return valve are closed to move the piston in a second direction that is opposite of the first direction.

14. The pump system of claim 6, wherein the first end of the cylinder rod assembly comprises a first rod coupled to the piston and extending from the first side of the piston and out of a first side of the hydraulic cylinder housing, wherein the second end of the cylinder rod assembly comprises a second rod coupled to the piston and extending from the second side of the piston and out of a second side of the hydraulic cylinder housing, wherein the first fluid end receives the first rod that extends out of the hydraulic cylinder housing, and wherein the second fluid end receives the second rod that extends out of the hydraulic cylinder housing.

15. A method of operating a pump system, comprising: supplying pressurized fluid via a first supply line into a piston chamber on a first side of a piston of a cylinder rod assembly;exhausting pressurized fluid via a second return line from the piston chamber on a second side of the piston, wherein supplying and exhausting the pressurized fluid pressurizes the first side of the piston relative to the second side of the piston to move the piston and the cylinder rod assembly in a first direction toward a first fluid end; and thensupplying pressurized fluid via a second supply line into the piston chamber on the second side of the piston;exhausting pressurized fluid via a first return line from the piston chamber on the first side of the piston, wherein supplying and exhausting of pressurized fluid pressurizes the second side of the piston relative to the first side of the piston to move the piston and the cylinder rod assembly in a second direction toward a second fluid end, the second direction is opposite of the first direction.

16. The method of claim 15, wherein the cylinder rod assembly further comprises: a first rod coupled to the piston and extending from the first side of the piston and out of a first side of a hydraulic cylinder forming the piston chamber; anda second rod coupled to the piston and extending from the second side of the piston and out of a second side of the hydraulic cylinder.

17. The method of claim 16, wherein the first fluid end receives an end of the first rod that extends out of the hydraulic cylinder, and wherein the second fluid end receives an end of the second rod that extends out of the cylinder rod assembly.

18. The method of claim 17, wherein one or more pumps are coupled to the first and second supply lines to supply the pressurized fluid into the piston chamber, and wherein one or more reservoirs are coupled to the first and second return lines to receive the pressurized fluid from the piston chamber

19. The method of claim 18, wherein a first supply valve along the first supply line that, when open, supplies the pressurized fluid to the piston chamber on the first side of the piston, wherein a second supply valve along the second supply line that, when open, supplies the pressurized fluid to the piston chamber on the second side of the piston, wherein a first return valve along the first return line that, when open, returns the pressurized fluid from the piston chamber on the first side of the piston to the one or more reservoirs, and wherein a second return valve along the second return line that, when open, returns the pressurized fluid from the piston chamber on the second side of the piston to the one or more reservoirs.

20. The method of claim 19, wherein a controller is configured to open the first supply valve and the second return valve while the second supply valve and the first return valve are closed to move the piston in the first direction toward the first fluid end, and wherein the controller is further configured to open the second supply valve and the first return valve while the first supply valve and the second return valve are closed to move the piston in the second direction.

21. A pump system, comprising: a hydraulic power end comprising a hydraulic cylinder having a hydraulic cylinder housing, and a cylinder rod assembly disposed at least partially in the hydraulic cylinder housing, the cylinder rod assembly comprising: a piston disposed in the hydraulic cylinder housing, anda rod section coupled to the piston and extending from the piston and out of a first side of the hydraulic cylinder, wherein a first end of the rod section is coupled to the piston; anda fluid end comprising a fluid end block, wherein a second end of the rod section is received in the fluid end block.