Patent Application
20200386244
The present disclosure relates to a hydraulic powering system and to a method of operating a hydraulic powering system. In particular, the hydraulic powering system includes a hydraulic cylinder, an accumulator, and a manifold assembly providing flow of hydraulic fluid between the hydraulic cylinder and the accumulator. The manifold assembly can also provide flow of hydraulic fluid between the hydraulic cylinder and the accumulator and a source of hydraulic fluid such as a hydraulic pump. The hydraulic powering system can be used in any environment where hydraulic power is desired. One particular area includes the application of hydraulic power for operating a well service pump in the oil and gas industry to assist with hydrocarbon production utilizing various downhole services such as hydraulic fracturing, acidizing, cementing, sand control, well control, and fluid circulation operations.
Hydraulic cylinders are often used to create a linear force. The movement of a piston within the hydraulic cylinder, as a result of the application of hydraulic fluid to one side of the piston, translates hydraulic energy from a hydraulic pump into a linear direction. Commonly, a piston rod extends from the piston through an end of the hydraulic cylinder. By application of hydraulic fluid to one side of the piston, the movement of the piston and the piston rod translates the energy into a first linear direction, and application of a hydraulic fluid to the other side of the piston can cause a linear force in the opposite direction. Hydraulic cylinders are often used as actuators on various mechanical devices including, loader arms, buckets, and claws on construction equipment. Hydraulic cylinders can also be used for operating a linear reciprocating, plunger-type pump, commonly referred as a “frac pump” often used to convey or pump a fluid into a well.
Accumulators have been used in power fluid systems to store potential energy for later use. While some accumulators utilize a piston or a diaphragm therein, they typically do not include a piston rod extending from the piston to outside of the accumulator. Instead, accumulators often include a hydraulic fluid on one side of the piston or diaphragm and a compressible material, such as a gas, on the other side of the piston or diaphragm. By compressing the gas, energy can be stored and later released by expanding the gas.
A hydraulic powering system is described that includes a hydraulic cylinder, an accumulator, and a manifold assembly. The hydraulic cylinder includes: (i) a hydraulic cylinder construction having a hydraulic cylinder wall and first and second hydraulic cylinder end caps forming an internal volume, a piston constructed to slide within the internal volume between the first and second hydraulic cylinder end caps and dividing the internal volume into an extend region and a retract region, and a piston rod extending from the piston and through the retract region and one of the first and second end caps to outside the hydraulic cylinder; (ii) an extend port in fluid connection with the extend region of the hydraulic cylinder; and (iii) a retract port in fluid communication with the retract region of the hydraulic cylinder. The accumulator includes: (i) an accumulator construction having an accumulator wall and first and second accumulator end caps forming an accumulator internal volume, an accumulator piston constructed to slide within the accumulator internal volume between the first and second accumulator end caps and dividing the accumulator internal volume into a hydraulic fluid region and a compressible gas region; and (ii) a hydraulic fluid port in fluid communication with the hydraulic fluid region of the accumulator. The manifold assembly includes a plurality of passageways therethrough providing fluid connection between: (i) a hydraulic fluid extend source and the hydraulic cylinder extend port and the accumulator hydraulic fluid port; and (ii) a hydraulic fluid retract source and the hydraulic cylinder retract port and the accumulator hydraulic fluid port.
A method of operating a hydraulic powering system is described that includes a step of feeding hydraulic fluid from an accumulator to a hydraulic cylinder retract region of a hydraulic cylinder side during a retract stroke of the hydraulic cylinder.
The present disclosure relates to a hydraulic powering system that includes a hydraulic cylinder, an accumulator, and a manifold assembly providing hydraulic fluid communication between the hydraulic cylinder and the accumulator. The manifold assembly can also provide communication of the hydraulic fluid between a source of hydraulic fluid, such as a hydraulic pump, and the hydraulic powering system. In addition, the present disclosure relates to a method of operating the hydraulic powering system.
Herein, example hydraulic powering systems, hydraulic cylinders, accumulators, and manifold assemblies are characterized in detail. Many of the specific features can be applied to provide advantage. There is no specific requirement that the various individual features and components be applied in an overall assembly with all of the features and characteristics described, however, in order to provide for some benefit in accord with the present disclosure.
Hydraulic cylinders generally operate by transferring energy into a linear direction. Depending on the side of the hydraulic cylinder into which the hydraulic fluid is introduced or removed, a piston with a piston rod extending therefrom moves in an extension direction or a retraction direction. The operation can be referred to as an extend stroke or as a retract stroke. It is often desirable to enhance the performance by increasing the speed and/or force of the extend stroke or by increasing the speed and/or force of the retract stroke. Enhancing the performance can additionally include leveling or making more uniform the application of force and avoiding spikes that sometimes occur at the end of an extend stroke (or the beginning of a retract stroke) or at the end of a retract stroke (or the beginning of an extend stroke). Furthermore, enhancing the performance of the hydraulic cylinder may include enhancing the performance of the hydraulic pump associated with, or powering the hydraulic cylinder, by utilizing the energy stored in an accumulator. Furthermore, using the stored energy in the accumulator may help reduce the demands on the hydraulic pump that causes undue wear on the hydraulic pump. For example, increasing the speed of the extend stroke or increasing the speed of the retract stroke may result in hydraulic fluid not being pulled into the hydraulic pump fast enough thereby causing cavitation or starving of the hydraulic pump. That, in turn, can cause wear on the hydraulic pump and shorten its life, and can also result in decreased performance of the hydraulic cylinder. In addition, there is a considerable amount of momentum that must be reversed every time the hydraulic cylinder switches between the extend stroke or the retract stroke, and the valve operation of the hydraulic pump might not be fast enough to provide the desired level of performance. The accumulator can also help absorb pressure spikes that may occur during operation of the hydraulic powering system. Accordingly, it is desirable to enhance the performance of the hydraulic cylinder by adding a force that is available for increasing the speed and/or force of the extend stroke and/or the retract stroke.
Now referring to
The hydraulic powering system 10 includes a manifold assembly 16 that can control flow of hydraulic fluid to, from, and between the hydraulic cylinder 12 and the accumulator 14. In addition, the manifold assembly can control flow of hydraulic fluid between the manifold assembly and a source of hydraulic fluid. The source of hydraulic fluid can be a pump arrangement that provides hydraulic fluid under pressure and also receives hydraulic fluid that can be, in turn, returned under pressure. The manifold assembly 16 can include a valve construction 21, such as a valve arrangement 18, that directs flow of hydraulic fluid through the manifold assembly 16. The valve construction 21 can be provided as an integral part of the manifold assembly 16 where it is built into the manifold assembly 16, or the valve construction 21 can be provided as a separate structure that attaches to the manifold assembly 16. As depicted, the valve arrangement 18 is a structure that can be attached to the manifold assembly 16 via fasteners 19. An advantage of providing the valve construction 21 as a separate structure is that the manifold assembly 16 can be provided having greater flexibility in terms of varied applications. That is, the valve construction 21 can be replaced with an alternative to adjust the operation of the hydraulic powering system 10. In addition, servicing of the hydraulic powering system 10 can be enhanced by providing the valve construction 21 as a separate structure that can more easily be detached from the manifold assembly 16 to provide for more convenient servicing thereof due the moving parts in the valve construction 21 may require servicing more often than the remainder of the manifold assembly 16.
The manifold assembly 16 includes an extend port 20 and a retract port 22. A hydraulic fluid powering source, such as a hydraulic fluid pump arrangement, can provide a fluid connection to the extend port 20 and the retract port 22 to operate the hydraulic powering system 10. The attachment can be via hydraulic lines. As illustrated in
Now referring to
The hydraulic cylinder 12 is illustrated in
The hydraulic cylinder 12 includes a position sensor 58 positioned within the piston rod 44, and an electronic sensor 59 that works with the position sensor 58 to identify where the piston or piston rod is at any time during a stroke. The position sensor 58 can be provided as a MTS brand sensor, and various position sensors for providing location information of a piston rod or a piston in a hydraulic cylinder are well known. Feedback from the piston rod 44 provides information useful that permits the valve arrangement to control flow of hydraulic fluid through the hydraulic powering system 10.
The accumulator 14 includes an accumulator wall 60 extending from an accumulator first end 62 to an accumulator second end 64, an accumulator first end cap 66 located at the accumulator first end 62, and an accumulator second end cap 68 located at the accumulator second end 64. The accumulator wall 60, the accumulator first end cap 66, and the accumulator second end cap 68 provide an accumulator interior region 70. The accumulator wall 60 can have a cylindrical shape forming the accumulator interior region 70. The accumulator 14 additionally includes a piston 72 that slides within the accumulator interior region 70 between the accumulator first end cap 66 and the accumulator second end cap 68. As shown, the piston 72 is in a discharged position 74 where the piston 72 is located adjacent the accumulator first end cap 66. The accumulator interior region 70 is divided into a first side region 76 and a second side region 78. The first side region 76 is located between the piston 72 and the accumulator first end cap 66, and the second side region 78 is located between the piston 72 and the accumulator second end cap 68. In general, the second side region 78 includes a compressible gas therein that can be fed into the second side region 78 via the gas charging port 80. The first side region 76 can be referred to as the hydraulic fluid region 77, and the second side region 78 can be referred to as the compressible gas region 79. In addition, because of the presence of a compressible gas within the second side region 78, it is expected that the piston 72 will not extend all the way to the accumulator second end cap 68. Now referring to
The accumulator 14 can be operated by introducing hydraulic fluid into the first side region 76 between the accumulator first end 66 and the piston 72 and thereby causing the piston 72 to move toward the accumulator second end cap 68. The compressible gas within the second side region 78 becomes compressed as the piston 72 moves toward the accumulator second end cap 68. Compressing the gas in the second side region 78 stores energy that can later be released as the piston 72 is permitted to move toward the accumulator first end cap 66. As the piston 72 moves toward the accumulator first end cap 66, the gas in the second side region 78 expands and the hydraulic fluid exits the first side region 76.
It should be understood that the accumulator 14 illustrated is a piston accumulator because it involves the movement of the piston 72 within the accumulator interior region 70. The particular size of the exemplified accumulator 14 is about 12 gallons. Other types of the accumulators are available and can be used including bladder accumulators. In order to achieve a similar energy storage using a single bladder accumulator, the bladder accumulator would generally require a greater diameter. Alternatively, multiple accumulators can be arranged, for example, in series or in parallel, to provide the desired energy storage and output.
Now referring to
The manifold assembly 16 includes two parts assembled together. The first part can be referred to as a cylinder base end 100 and the second part can be referred as an accumulator base end 102. The cylinder base end 100 is shown isolated in
The cylinder base end 100 includes a plurality of bolt holes 120 for connection with the hydraulic cylinder 12 via the bolts 122 and includes bolt holes 124 for connection with the accumulator end 102 via bolts 126. Similarly, the accumulator base end 102 includes a plurality of bolt holes 123 for connection with the accumulator 14 via the bolts 123, and includes bolt holes 125 for connection with the hydraulic cylinder 12 via the bolts 126. While bolt holes and bolts are identified herein, it should be understood that various other fasteners can be used in place of or in combination with bolt holes and bolts.
Now referring to
The cylinder base end includes Port 2 which is connected via conduit 112 to the first side region 76 of the accumulator 14, and Port 3 which is connect to the retract port 22 via the conduit 114.
Because the cylinder base end 100 and the accumulator base end 102 can be made from a solid metallic material such as steel, the conduits can be drilled out advantageously by drilling straight lines. The resulting openings can be plugged. For example, in order to create the conduit 114 between Port 3 and the retract port 22, a first conduit can be drilled out from the drill port 130 to the Port 3, and a second conduit can be drilled out from the drill port 132 to the retract port 22. The drill ports 130 and 132 can be plugged. Additional drill ports 134, 136, and 138 are identified that form conduits 135, 137, and 139.
Pressure control valves 140 and 142 are provided to regulate the pressure in the extend region 48 and in the retract region 50. The pressure control valves 140 and 142 can be provided as relief valves and/or as sequence valves. If the pressure control valve 140 is a relief valve and it is triggered, then hydraulic fluid can flow from the retract region 50 to the extend region 48 via conduit 135. If the pressure control valve 142 is a relief valve and it is triggered, the hydraulic fluid can flow from the extend region 48 to the retract region 50 via the conduits 137 and 143. The valves 140 and 142 include check valves that provide for one way flow of hydraulic fluid when the valves are triggered. The pressure control valves 140 and 142, when provided as relief valves, can be provided as 6,000 psi and 3,000 psi valves. It should be understood that the relief valves can be provided with desired any thresholds.
In addition, a through hole 151 can be provided for the position sensor 58 and 59, and a check valve 152 can be provided for make up hydraulic fluid when desired, such as when there is cavitation in the hydraulic cylinder.
The accumulator base end 102 is illustrated in
The accumulator base end 102 includes an accumulator charge/discharge port 170. Hydraulic fluid flows through the accumulator charge/discharge port 170 when charging or discharging hydraulic fluid from the first side region 76. Hydraulic fluid flows to and from the accumulator charge/discharge port 170 via the conduit 172 which is in communication with the conduit 112 and Port B in the hydraulic cylinder base end 100. The accumulator base end 102 additionally includes pressure control valves 174 and 176, and a dump valve 178. The pressure control valves 174 and 176 can be provided as relief valves and/or as sequence valves. If the pressure control valves 174 and 176 are provided as relief valves, once a maximum pressure is triggered, then hydraulic fluid is permitted to flow from the first side region 76 via the conduit 180 and through the dump line 28. The relief valves 174 and 176 can be provided having check valves to provide one way flow. In addition, the relief valves 174 and 176 would work together to provide desired flow. The dump valve 178 permits bleeding of residual pressure if there is a power loss. As illustrated in
The valve construction 21 can be provided as a control valve. An example of a valve construction 21 that provides control is the valve arrangement 18 which is depicted in the form of a two position and three way valve. When desired, the valve arrangement 18 can provide a common connection between Port 1 and Port 2, and can provide a common connection between Port 2 and Port 3. The valve arrangement 18 can include a first spring chamber 190 and a second spring chamber 192. In general, the first and second spring chambers 190 and 192 include a spring that keeps a replaceable spool in position when the hydraulic powering system 10 in unpowered. In addition, the valve arrangement 18 can include a pilot valve 194 which provides oil to drive the valve arrangement 18. It should be appreciated that the valve arrangement 18 can be driven by a computer control system or other electronic means that takes into account the various operational parameters. It should be appreciated that the valve construction 21 can be provided as a control valve other than as a two position and three way valve. For example, the valve construction 21 can be provided as a plurality of valves, together or separate, that provide the desired control of hydraulic fluid flow through the manifold assembly 16. The plurality of valves can be arranged in parallel and/or series to provide the desired flow control.
An advantage of the hydraulic powering system 10 is that when the hydraulic pump is providing hydraulic fluid to the extend region 48 of the hydraulic cylinder 12, hydraulic fluid can also be directed to the first side region 76 of the accumulator 14 in order to charge the accumulator 14. In certain circumstances, the extend stroke of the hydraulic cylinder 12 can provide the desired work. The time of the retract stroke, in contrast, reduces the work interval. By accelerating the retract stroke, it may be possible to operate the hydraulic cylinder more efficiently. Accordingly, the hydraulic powering system 10 can rely upon the stored energy in the accumulator 14 to accelerate the movement of the piston 42 during the retract stroke. This is accomplished by permitting the hydraulic fluid from the first side region 76 of the accumulator 14 to flow via the hydraulic fluid retract line 52 into the retract region 50 of the hydraulic cylinder 12. This can occur when the valve arrangement 18 provides communication between Port 2 and Port 3.
By utilizing the manifold assembly, the use of hydraulic hoses can be minimized. Several problems result from using hydraulic hoses to provide connections between the source of hydraulic fluid and the hydraulic cylinder and the accumulator. One problem is that the hoses cause a mess of lines that can become tangled and may even be hooked up incorrectly. Another problem is that the hoses can wear more quickly and require replacement. Another problem is that the hoses are more susceptible to leaking and/or bursting which can cause safety and pollution concerns. The servicing of the hoses by periodic replacement or by addressing a hose rupture issue likely requires taking the hydraulic cylinder out of use thereby resulting in loss of productivity. Furthermore, the use of hoses can result in a loss of energy as a result of the expansion of the hoses being subject to relatively large internal pressures. An expansion as a result of application of pressure may result in loss of energy and also a loss in responsiveness. In high performance industrial equipment such as frac pumps, a decrease in responsiveness can cause a delay or reduction in performance. The conduits within the manifold assembly are not subject to expansion under pressure the same way as hoses. In addition, long runs of hoses can permit pressure drop to occur which is not desirable. The use of a manifold assembly according to the present disclosure addresses these problems and provides for better control.
Now referring to
Again, the principles, techniques, and features described herein can be applied in a variety of system, and there is no requirement that all of the advantageous features identified be incorporated in an assembly, system, method, or component to obtain some benefit according to the present disclosure.
It should be understood that various changes and modifications to the preferred embodiments described herein will be apparent to those skilled in the art. Such changes or modifications may be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is, therefore, intended that such changes and modifications be covered by the appended claims.
This application claims the benefit of provisional patent Application Ser. No. 62/857,071 filed with the United States Patent and Trademark Office on Jun. 4, 2019. The entire disclosure of U.S. Application Ser. No. 62/857,071 is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62857071 | Jun 2019 | US |
