Embodiments described herein relate to high pressure pumps used in oil and gas service.
Production of oil and gas is a trillion-dollar industry. Producers continually seek ways to increase the speed and flexibility, and lower the cost of, production apparatus for onshore and offshore oil and gas production. Equipment downtime is costly, so efficient repair and replacement of equipment in the field is valuable. High pressure pumps are routinely used in oil and gas service to pump various fluids, such as processing fluids, hydraulic fracturing fluids, and flush fluids through hydrocarbon reservoirs. Failure of such a pump shuts down production.
Typically, high pressure pumps are switched on and off when needed. Such power cycling reduces the lifetime of the pump. Additionally, different pumps are typically used for different service requiring different pressure or flow rate. High pressure pumps capable of producing varying flow rates and pressures and capable of idling without being shut off, are needed in the industry.
Embodiments described herein provide a pump, comprising a drive shaft coupled to a drive; a wobble plate attached to the drive shaft by a swivel mount; a plurality of displacement rods, each having a first end and a second end, with the first end of each displacement rod disposed against a first surface of the wobble plate and the second end of each displacement rod connected with a plunger; and a tilt actuator assembly disposed around the drive shaft, the tilt actuator assembly comprising a slider having an interior surface with a slot formed therein and a thruster coupled to the slider and extending toward a second surface of the wobble plate opposite the first surface, the tilt actuator assembly further comprising a key extending radially outward from the drive shaft and mated with the slot and a linear actuator slidably disposed against the slider.
A pump, comprising a drive shaft coupled to a drive; a wobble plate attached to the drive shaft by a ball-shaped swivel mount with a wobble plate key extending radially inward from the wobble plate to the swivel mount; a plurality of displacement rods, each having a first end and a second end, with the first end of each displacement rod disposed against a first surface of the wobble plate and the second end of each displacement rod connected with a plunger; a thrust bearing between each displacement rod and the wobble plate; a tilt actuator assembly disposed around the drive shaft, the tilt actuator assembly comprising a slider with a slot formed therein and a thruster coupled to the slider and extending toward a second surface of the wobble plate opposite the first surface; and a key extending radially outward from the drive shaft and mated with the slot.
Other embodiments provide a pump, comprising a drive shaft coupled to a drive; a wobble plate attached to the drive shaft by a ball-shaped swivel mount with a wobble plate key extending radially inward from the wobble plate to the swivel mount; a plurality of displacement rods, each having a first end and a second end, with the first end of each displacement rod disposed against a first surface of the wobble plate and the second end of each displacement rod connected with a plunger; a thrust bearing between each displacement rod and the wobble plate; a tilt actuator assembly disposed around the drive shaft, the tilt actuator assembly comprising a slider with an interior surface that has a slot formed therein and a thruster coupled to an exterior surface of the slider and extending toward a second surface of the wobble plate opposite the first surface, the slider attached to the drive shaft by a guide ring; a key extending radially outward from the drive shaft and the guide ring, and mated with the slot; and a linear actuator slidably disposed within the drive shaft and coupled to the slider and to a hydraulic member located at a fluid end of the pump.
So that the manner in which the above-recited features of the present invention can be understood in detail, a more particular description of the invention, 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 invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
To facilitate understanding, identical descriptors have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
The pump 100 has a drive shaft 116 disposed along a central axis 118 of the pump 100. A wobble plate 120 is disposed around the drive shaft 116 and rotationally coupled to the drive shaft 116. The wobble plate 120 is tilted to provide reciprocating motion for driving the pumping mechanism of the pump 100. A thruster assembly 122 is attached to a slider 124 disposed around the drive shaft, and the thruster assembly 122 extends toward the wobble plate 120, contacting the wobble plate 120 at a contact location 126. The slider 124, and thruster assembly 122, are both rotationally coupled to the drive shaft 116. The thruster assembly 122 is actuated along the axis 118 of the pump 100 to move the contact location 126 in a direction nearly parallel to the axis 118 of the pump 100. Movement of the contact location 126 adjusts a tilt angle of the wobble plate 120, and the pump 100 is configured such that such adjustment can be performed while the pump 100 is operating.
A plurality of displacement rods 128 are disposed through the bearing plate 108, and contact the wobble plate 120 at a first surface 130 thereof (also shown in
The thruster assembly 122 contacts the second surface 138 at a rotational thrust bearing 210 that allows rotational freedom for the thruster assembly 122 to change angular position with respect to the second surface 138 of the wobble plate 120. The wobble plate, here, is a plate with a cylindrical rim 212, a cylindrical hub 213 that accommodates the drive shaft 116 (
The linear actuator 302 has a second end 310 that extends to a rotary bearing 312. The linear actuator 302 extends into a first side 314 of the rotary bearing 312. A hydraulic member 316 is disposed against a second side 318 of the rotary bearing 312, opposite from the first side 314, to provide force to move the rotary bearing 312 in the axial direction of the pump 100, and thus to displace the linear actuator 302. A rod end 320 of the hydraulic member 316 contacts the rotary bearing 312, while a piston end 322 of the hydraulic member 316, opposite from the rod end 320, is disposed within a cylinder 324. A piston 326 is coupled to the piston end 322. An end plate 328 is attached to the fluid end plate 110 and is disposed against an end of the cylinder 324 to seal the end of the cylinder 324. The end plate 328 and the piston end 322 cooperatively define a retraction chamber 330 within the cylinder 324. Hydraulic fluid is pressured into the retraction chamber 330 to displace the hydraulic member 316 toward the wobble plate 120, which in turn displaces the rotary bearing 312 and the linear actuator 302 in the axial direction to retract the wobble plate 120 toward a more perpendicular orientation with respect to the drive shaft 116. Opposite the piston 326 from the retraction chamber 330 is an extension chamber 331, between the piston 326 and a piston plate 333. Hydraulic fluid is pressured into the extension chamber 331 to displace the hydraulic member 316 away from the wobble plate 120, which displaces the rotary bearing 312 and the linear actuator 302 in the axial direction to extend the wobble plate 120 toward a more angled orientation with respect to the drive shaft 116. The hydraulic member 316 does not rotate with the drive shaft. Methods other than hydraulic displacement, for example gas displacement or electromechanical displacement, can be used to displace the rotary bearing 312 and the linear actuator 302.
An extension port 1206 is formed through the piston plate 333 to provide fluid communication to the extension chamber 331 such that hydraulic fluid can be flowed into and out of the extension chamber 331. The extension port 1206 can be provided at any convenient location, and more than one extension port 1206 can be used. Where other methods of displacement are used, the ports 1202, 1204, and 1206 may be omitted, and other enabling features, such as attachments, conduits, or ports, may be included.
A spring 402 biases the rotary bearing 312 toward the fluid end 132 of the pump 100. The spring 402 generates a reaction force that opposes the hydraulic force of the hydraulic member 316. When the hydraulic force of the hydraulic member 316 is reduced below the reaction force of the spring 402, or when the hydraulic force reverses in direction by operation of the extension chamber 331, the rotary bearing 312 is displaced toward the fluid end 132. Movement of the rotary bearing 312, translated through the linear actuator 302 and the pin 308, moves the slider 124 toward the fluid end 132 and increases the tilt angle of the wobble plate 120. The interaction of the rotary bearing 312 and the hydraulic member 316 allows tilt angle of the wobble plate 120 to be adjusted while the pump 100 is in operation. The spring 402 is disposed around the linear actuator 302 between the rotary bearing 312 and the bearing plate 108, which provides support for the spring 402 to generate the reaction force. The linear actuator 302 extends through the bearing plate 108 to the rotary bearing 312, which is located in the displacement section 152 of the pump.
Referring again to
The slider 124 is constrained to rotate with the drive shaft 116 by operation of a key 336. The key 336 fits in a slot (not shown in
The wrist pin 308 has a passage 508 into which the linear actuator 302 is inserted to couple the linear actuator 302 to the wrist pin 308. The passage 508 is formed through the wrist pin 308 in a direction transverse to the axis of the wrist pin 308. The linear actuator 302 has at least one lateral lubricant conduit 510 extending radially outward from the axial lubricant conduit 332. Here, there are two lateral lubricant conduits 510, but any number could be used. The lateral lubricant conduit 510 provides fluid communication between the axial lubricant conduit 332 and an annular gap 512 between an outer surface 514 of the linear actuator 302 and an inner surface 516 of the passage 508. Lubricant can flow from the axial lubricant conduit 332 through the lateral lubricant conduit 510 to the annular gap 512. The wrist pin 308 has an axial lubricant passage 518 that provides a flow pathway for lubricant to fill the lubricant spaces within the cross-head assembly 506.
A plunger 624 is coupled to the second end 622 of each displacement rod 128. The plunger 624 extends through the fluid end plate 110 into a corresponding module assembly 134 to propel fluid through the discharge valve of the module assembly 134 during the power stroke, when the displacement rod 128 is extended, and to draw fluid through the suction valve of the module assembly 134 into the module assembly 134 during the suction stroke, when the displacement rod 128 is retracted. The sections 610 and 612 of the displacement rod 128, and the plunger 624, are all hollow in this view to reduce overall weight of the pump 100, but these components may be solid.
A flexible force resistant member 630, in this case a spring, is disposed around the second section 612 of each displacement rod 128. The force resistant member 630 is situated against the attachment plate 620 at a first end thereof and against a collar 632 attached to the fluid end plate 110 at a second end thereof. The force resistant member 630 applies a retracting force to bias the displacement rods 128 toward a retracted position so that when the wobble plate rotates to release the power stroke of the displacement rod 128, the force resistant member 630 applies retracting force to the attachment plate 620, thus moving the displacement rod 128 toward the retracted position and accomplishing the suction stroke of the displacement rod 128. As the wobble plate further rotates to apply the power stroke of the displacement rod 128, the force resistant member 630 is compressed and absorbs mechanical energy to be released during the suction stroke.
The enclosure 650 has two sections. A first section 660 has dimension selected to contain the coupling plate 654, and thus has a radial extent substantially larger than an outer radius of the linear actuator 302. The first section 660 includes the first side 314. A second section 662 has a radial extent smaller than that of the first section 660. The first section 660 and the second section 662 are joined by a shoulder 664. The lubricant port 334 is formed through the shoulder 664 and fluidly couples to a lubricant plenum 666 formed within the shoulder 664 adjacent to the second end 310 of the linear actuator 302. The lubricant conduit 332 fluidly couples to the lubricant plenum 666.
The shoulder 664 has a recess 668 that is co-axial with the axis 118 and faces the second end 310 of the linear actuator 302. A first thrust bearing 670 is disposed in the recess 668. The first thrust bearing 670 is thus supported by the shoulder 664. The first thrust bearing 670 comprises a plurality of rings with one or more rollers to provide differential rotary motion of the rings. Thus, a first ring 672 of the first thrust bearing 670 contacts the shoulder 664 and does not rotate. A second ring 674 of the first thrust bearing 670 contacts the flange portion 658 at a location where the flange portion 658 joins the hub portion 656, and is thus rotatable with the linear actuator 302 and the drive shaft 116. A third ring 676 of the first thrust bearing 670 houses at least three rollers (not shown) that couple the first and second rings 672 and 674. The first thrust bearing 670 participates in decoupling axial thrust of the hydraulic member 316 from rotary motion of the linear actuator 302.
A second thrust bearing 680 is located between the second side 314 and the flange portion 658. Thus, the flange portion 658 of the coupling plate 654 extends between two thrust bearings within the rotary bearing 312. The first thrust bearing 670 contacts the coupling plate 654 on a first side thereof and the second thrust bearing 680 contacts the coupling plate 654 on a second side thereof opposite from the first side. Here, the flange portion 658 of the coupling plate 654 is sandwiched between the first and second thrust bearings 670 and 680. The second thrust bearing 680 comprises a plurality of frustoconical rollers 682, each coupled to a hub ring 684 by an axle 686. A pair of rings 688 capture the rollers 682 and participate in distributing axial thrust of the hydraulic member 316 throughout the structure of the rotary bearing 312. In this case, an end of the hub portion 656 of the coupling plate 654 extends through the hub ring 684 to contact a shoulder 690 of the linear actuator 302.
The gimbal mount 708 comprises a ring 712 that is rotatably attached to the first end 610 of the displacement rod 128 at a gimbal attachment location 714 spaced apart from the spherical end cap 702. There are two gimbal attachment locations 714 for each ring 712, located on opposite sides of the displacement rod 128. The two gimbal attachment locations 714 for each ring 712 define a rotational axis that is substantially perpendicular to a radius of the wobble plate 120 drawn to intersect the axis of the displacement rod 128. Thus, as the wobble plate 120 rotates, each tilt pad bearing 704 tilts toward the drive shaft 116 and away from the drive shaft 116. The tilt pad bearing 704 is attached to the ring 712 at ring attachment locations 716 that are angularly displaced from the gimbal attachment locations 714 by an angle of 90°. Each tilt pad bearing 704 has two fingers 718 on opposite sides of the tilt pad bearing 704. The fingers 718 rotatably attach to the ring 712 on opposite sides thereof. In this way, the tilt pad bearing 704 is allowed two perpendicular axes of rotation to maintain contact with the first surface 130 of the wobble plate 120 during power and suction phases of the wobble plate rotation. Lubricity of the slip face 706 and the internal surface 710 is maintained by lubricant provided through a lubricant port 720 in a side 722 of the tilt pad bearing 704. The lubricant port 720 fluidly communicates with an interior plenum 724 of the tilt pad bearing 704. The interior plenum 724 further fluidly communicates with the slip face 706 through one or more ports (not shown) formed in a bearing surface 726 of the tilt pad bearing 704.
A thrust axle 758 is disposed within a passage 760 formed through the thrust end 754. The thrust block 752 includes a thrust bearing 762 with a spherical slip face 764 that contacts the spherical thrust end 754 of the thrust rod 750. A collar ring 766 is disposed within the thrust block 752 adjacent to the opening 756 to provide a smooth contact surface for the thrust rod 750 and to prevent direct contact between the thrust rod 750 and the edges of the opening 756. The thrust bearing 762 and collar ring 766 together define a pair of axle openings 768 formed at opposite sides of the thrust block 752. The thrust axle 758 extends outward from the thrust end 754 into and through the axle openings 768. Here, each end of the thrust axle 758 protrudes slightly beyond the sides of the thrust block 752, but any convenient extent can be used. Transverse movement of the thrust rod 750 within the thrust block 752 is constrained by the collar ring 766.
The thrust axle 758 has a central portion 770 and two end portions 772. The central portion 770 is cylindrical to match the cylindrical inner profile of the passage 760. Each edge portion 772 is tapered in a frustoconical shape. Here, a small curvature radius joins the central portion 770 with each edge portion 772. The tapered edge portions 772 provide a tolerance for non-axial rotation of the thrust axle 758. The non-axial rotation of the thrust axle 758 provides some freedom to absorb and limit yaw movement of the wobble plate 120, but controls such motion within the confines of the axle openings 768. The thrust axle 758, the collar ring 766 and the thrust bearing 762 thus form a yaw limit assembly that limits yaw movement of the wobble plate 120.
The suction valve cartridge 902 is a single piece structure that is removable from the recess 910. In this case, the suction valve cartridge 902 couples to the suction portion 802 by threading into the recess 910, thus enabling easy removal of the suction valve cartridge 902 from the recess. The suction valve cartridge 902 can be disassembled by decoupling the seat ring 908 from the side wall 912. The valve retainer 916 can then be removed at the first end 904, followed by the valve spring 918, valve body 920, and valve seat 922. The modular assembly and disassembly of the suction valve cartridge 902, and components thereof, enable easy replacement of all or parts of the suction valve cartridge 902.
A suction manifold (not shown) is typically attached to the suction portion 802 near the second end 906 of the suction valve cartridge 902 to supply fluid for pumping. The valve body 920 disengages from the valve closure surface 926 to release fluid from the suction manifold into an interior plenum 928 of the module assembly 134. A plunger port 930 is located in an attachment end 932 of the module assembly 134. A plunger fitting 934 couples into the plunger port 930 to provide smooth travel of the plunger 624 (
A valve spring 1034 is disposed between a back surface of the valve body 1032 and a valve retainer 1036. The valve retainer 1036 is threaded to engage with the threaded fourth section 1140 of the discharge valve cartridge 1002. The discharge valve cartridge 1002 is removable as a unit, enabling easy replacement of the discharge valve cartridge 1002 in the module assembly 134. Removing the valve retainer 1036 allows for installation and removal of the valve seat 1018, the valve body 1032 and the valve spring 1034. The valve spring 1034 biases the valve body 1032 against the valve seat 1018, with compression provided by the valve retainer 1036 when installed. The discharge valve cartridge 1002 is secured within the recess 1104 of the discharge portion 804 by a retention plate 1042, which in this case threads into the discharge portion 804 to close the recess 1104 and is fastened to the valve retainer 1036 by a fastener.
When the plunger 624 (
The pump 100 is a variable stroke pump. Operation of the tilt linkage described herein adjusts the tilt angle of the wobble plate. Tilt angle adjustment can be performed when the pump 100 is idle or when the pump is operating. For example, while the pump 100 is operating, wobble plate tilt angle can be set to zero to place the pump 100 in a standby mode. While in standby mode, the drive shaft is still turning, so the pump 100 can operate at zero displacement. When the tilt angle is changed to a positive non-zero value, the pump 100 begins producing displacement in relation to the tilt angle of the wobble plate. The pump 100 can operate continuously as the tilt angle is adjusted from zero to a maximum, so displacement of the pump 100 can be continuously and dynamically varied from zero to a maximum. This enables temporary idling of the pump 100 when needed without completely shutting the pump off. This also enables gradual ramping up of pump displacement to avoid disruptive startup and shutdown of the pump 100. In this way, adjustment of the tilt actuator changes stroke length of the pump, so pump flow rate can be continuously adjusted with constant drive input. Controls can be operatively coupled to the hydraulic source (or other actuator type) that adjusts the tilt angle to provide easy adjustment of pump operation. The reciprocating displacement operation of the pump 100 allows pumping of slurries, compressible fluids, and incompressible fluids. The pump 100 can, for example, be readily used as a fracturing pump.
While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof.
This application is a continuation of U.S. patent application Ser. No. 16/852,814, filed Apr. 20, 2020, which is a continuation of U.S. patent application Ser. No. 16/662,513, filed Oct. 24, 2019, which issued as U.S. Pat. No. 10,670,003, on Jun. 2, 2020; both of which are incorporated herein by reference in their entireties.
Number | Date | Country | |
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Parent | 16852814 | Apr 2020 | US |
Child | 17305370 | US | |
Parent | 16662513 | Oct 2019 | US |
Child | 16852814 | US |