Double-pump synchronous driving alternate continuous row ultra-low alternating load deep pumping lifting system

Abstract

This invention provides a single-rod, dual-pump synchronously driven, alternating, continuous, ultra-low alternating load deep pumping lifting system, comprising a double-rod working cylinder, at least one set of gear assembly supports, and two parallel-arranged pumps. The upper end of the gear assembly supports is connected to the double-rod working cylinder, and the lower end is connected to the two parallel-arranged pumps via double-pump couplings. Two parallel rack rods are provided inside the working cylinder, and the lower ends of the two rack rods are connected to the plungers of the two pumps respectively. Racks for meshing with gears installed in the gear assembly supports are fixed on the two rack rods. Flow holes are provided on the gear assembly supports. This new lifting system can significantly reduce or even completely avoid contact fatigue damage at tubing thread connections, reduce the number of wells lying down due to tubing thread leakage, and lower the maintenance costs of mechanically operated wells. It also achieves continuous wellhead drainage and improved pump efficiency through deep pumping with small pumps.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and in particular to a single-rod dual-pump synchronous drive alternating continuous discharge ultra-low alternating load deep extraction and lifting system. Background Technology

[0002] Rod pump lift has always been one of the most important oil production methods in the petroleum industry. Rod pump lift wells account for 80% of oil wells internationally and nearly 95% domestically. As a mature, reliable, and widely used oil production method, it has unparalleled advantages compared to other methods. However, since the invention of rod pump lift technology, its design principle has had an inescapable bottleneck problem that restricts and shortens the service life of the pump-lift tubing string. This persistent and harmful factor shortens the pump inspection cycle and is the primary cause of tubing thread leakage and well collapse, which accounts for the highest proportion of pump-lift tubing string failures. This harmful factor is the alternating fluid column load that the tubing repeatedly bears during the up and down strokes of the pumping unit.

[0003] To simplify the explanation of the principle, this analysis focuses only on the static load, which accounts for the largest proportion. As is well known, during the upstroke of a pumping unit, the fluid column load is transferred from the tubing to the plunger of the pump, and during the downstroke, the fluid column load is transferred back from the plunger to the tubing. This cycle repeats continuously, with the fluid column load frequently alternating on the tubing. This alternating load varies considerably depending on factors such as the well's dynamic fluid level, casing pressure differential, well fluid density, plunger diameter, and the number of production strokes, but it generally reaches 20–60 kN, or even more. It is conceivable that such a large force, frequently alternating and pulsating on the tubing, can easily lead to contact fatigue at the tubing thread connections, eventually causing slight loosening of the threads, and in severe cases, leakage, wellbore collapse, or even thread breakage and fall into the well. Moreover, the larger the alternating fluid column load, the more pronounced this problem becomes. Summary of the Invention

[0004] The purpose of this application is to provide a single-rod dual-pump synchronous drive alternating discharge ultra-low alternating load deep pumping lifting system that can automatically cancel the alternating load of the liquid column in the oil pipe during the up and down strokes, thereby eliminating or requiring the oil pipe to bear only a very small alternating load, and can achieve continuous drainage of the oil pipe.

[0005] This application is implemented as follows:

[0006] This application provides a single-rod dual-pump synchronous drive alternating continuous ultra-low alternating load deep pumping lifting system, characterized in that it includes a double-rod working cylinder, at least one set of gear assembly supports, and two parallel oil pumps arranged left and right. The upper end of the gear assembly support is connected to the double-rod working cylinder, and the lower end is connected to the two parallel oil pumps arranged left and right through the double-pump upper couplings. Two parallel rack rods are provided in the rod working cylinder, and the upper end of one rack rod is eccentrically connected to a sucker rod. The lower ends of the two rack rods pass through the gear assembly support and the corresponding two parallel oil pumps arranged left and right, respectively, and are connected to the plungers of the two oil pumps. Racks for meshing with gears arranged in the gear assembly support are fixed on the two rack rods, and flow holes are provided on the gear assembly support.

[0007] In some optional embodiments, the gear assembly support is connected to the upper coupling of the dual pump via a connecting rod. Each gear assembly support includes a lower gear support and an upper gear support connected in sequence. The upper gear support and the lower gear support are respectively provided with rack rod mounting holes, connecting rod mounting holes, and flow holes for the two rack rods to pass through. A gear bracket and a gear mounted on the gear bracket are provided between the upper gear support and the lower gear support.

[0008] In some optional implementations, two coaxial gear assembly supports are provided, which are mirror-symmetrically arranged. A combined pipe is provided between the two gear assembly supports. The upper ends of the two parallel oil pumps are connected to the lower gear support at the bottom end through a double pump connecting section, a double pump upper coupling, and a double pump upper connector from bottom to top. The lower gear support, the upper gear support, and the double pump upper coupling all have the same coaxial multi-hole structure on their axes, that is, they are respectively provided with rack tie rod mounting holes, connecting rod mounting holes, and flow holes.

[0009] In some alternative implementations, the double-pull-rod working cylinder, the combined pipe, and the double-pump upper connector are all coaxial hollow cylindrical structures.

[0010] In some alternative implementations, sealing grooves are provided on the mating end faces of the lower gear support, upper gear support, combined pipe, upper double pump connector, and upper double pump coupling, respectively. Sealing steel rings are arranged in the sealing grooves, and the sealing steel rings are pressed together by connecting rods to achieve overall sealing of the assembly.

[0011] In some alternative implementations, the threaded end of the upper gear lower support is connected to the double tie rod working cylinder, the double tie rod working cylinder is connected to the pump upper oil pipe, and the threaded end of the lower gear lower support is connected to the threaded end of the double pump upper connector.

[0012] In some alternative implementations, the flow passage is located on the circumferential surface and / or center of the entire device.

[0013] In some alternative implementations, both the lower gear support and the upper gear support are respectively provided with gear brackets by welding, riveting, or inlaying. The mating surfaces of the gear brackets are provided with bayonet structures to achieve positioning and limiting assembly.

[0014] In some alternative implementations, two parallel oil pumps are connected together below their fixed valves to form a single inlet device, i.e., connected in series using a single tailpipe tubing.

[0015] In some alternative implementations, one rack and pinion rod is connected to an extension rod via a rod coupling, the top of the extension rod is connected to an eccentric rod head and a rod head cap assembly, and a sucker rod is connected above the eccentric rod head.

[0016] In some alternative implementations, a disconnector connector is connected to the eccentric rod head, and the sucker rod string is connected to the disconnector coupling sleeve via a sucker rod coupling and the disconnector connector. The disconnector coupling sleeve impacts the disconnector connector connected to the eccentric rod head to achieve automatic limiting connection.

[0017] In some alternative implementations, the two parallel oil pumps have identical specifications, structures, and strokes, so the liquid column loads during the up-and-down pumping process are also exactly the same.

[0018] The beneficial effects of this application are:

[0019] This invention utilizes a rack and pinion rod, a gear assembly support, and parallel dual pumps. During the pumping process of the sucker rod string, the rack and pinion rod drives the pump plunger to achieve alternating up and down lifting. When the left plunger is at bottom dead center, the right plunger is at top dead center. When the left plunger begins to move upward, the right plunger begins to move downward, and this cycle repeats to achieve alternating lifting. Because the parallel dual pumps are rigidly connected to the tubing string via threaded connections, when the left plunger moves upward, the plunger's traveling valve closes, reducing the liquid column load on the left pump barrel. Conversely, when the right plunger moves downward, the plunger's traveling valve opens, increasing the liquid column load on the right pump barrel. Since the parallel dual pumps have identical specifications, structure, and stroke, the magnitude of the liquid column load increase and decrease during the pumping process is also exactly the same. For example, when the left pump barrel reduces the liquid column load by 30kN, the right pump barrel simultaneously increases the liquid column load by 30kN, and vice versa. In this way, the load increase and decrease of the entire tubing string are almost equal at the same time, and the forces cancel each other out. The tubing string is no longer equivalent to bearing the alternating load of the liquid column, which greatly reduces or even completely avoids contact fatigue failure at the tubing thread connection, reduces the number of wells lying down due to tubing thread leakage, and lowers the maintenance cost of mechanically operated wells. Moreover, because the left and right parallel dual pumps are seamlessly connected and synchronously alternately pump in and out fluid, the function of continuous fluid discharge from the wellhead is also realized. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a single-pump, dual-pump synchronous drive, alternating continuous discharge, ultra-low alternating load deep extraction and lifting system provided in this application embodiment (pump lower left, upper right extraction state diagram).

[0022] Figure 2 This application provides a schematic diagram of the piston's left-upper-right-lower-right-lower pumping state in a single-pump synchronous drive alternating continuous discharge ultra-low alternating load deep pumping lifting system.

[0023] Figure 3 This is a cross-sectional view of the rack tie rod in the embodiment of this application (with some parts hidden).

[0024] Figure 4 This is an exploded view of the gear support assembly in an embodiment of this application.

[0025] Figure 5 This is a schematic diagram of the mounting holes and flow holes on the gear support in this embodiment (parts are hidden).

[0026] In the diagram: 1—Double tie rod working cylinder, 2—Eccentric rod head, 3—Rod head pressure cap, 4—Extended tie rod, 5—Tie rod coupling, 6—Right rack tie rod, 7—Connecting rod, 8—Connecting rod nut, 9—Lower gear support, 10—Upper gear support, 11—Sealing steel ring, 12—Left rack tie rod, 13—Combined pipe, 14—Double pump upper connector, 15—Double pump upper coupling, 16—Pump cylinder connecting section, 17—Drive gear, 18—Gear bracket, 19—Disconnector pair Connector, 20—Decoupler coupling sleeve, 21—Decoupler connector, 22—Suck rod coupling, 23—Suck rod string, 24—Left pump barrel, 25—Left upstream valve, 26—Left plunger, 27—Left downstream valve, 28—Left fixed valve, 29—Right upstream valve, 30—Right plunger, 31—Right downstream valve, 32—Right pump barrel, 33—Right fixed valve, A—Rack and pinion rod mounting hole, B—Connecting rod mounting hole, C—Central flow hole, D—Circumferential flow hole. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0031] This embodiment provides a single-rod dual-pump synchronous drive alternating continuous ultra-low alternating load deep pumping lifting system, including a dual-rod working cylinder 1, at least one set of gear assembly supports, and two parallel left and right oil pumps. The upper end of the gear assembly support is connected to the dual-rod working cylinder 1, and the lower end is connected to the two parallel left and right oil pumps through the dual-pump upper coupling 15. Two parallel rack rods are provided in the working cylinder 1, corresponding to the left rack rod 12 and the right rack rod 6 in the figure. The upper end of the left rack rod 12 is eccentrically connected to the sucker rod 23. The lower ends of the two rack rods pass through the gear assembly support and the corresponding two parallel left and right oil pumps, respectively, and are connected to the plungers of the two oil pumps. Racks for meshing with the gears provided in the gear assembly support are fixed on the two rack rods, and flow holes are provided on the gear assembly support.

[0032] The working principle of this invention is as follows: Before the entire device is lowered into the well, the anti-impact distance of the pump plunger and the stroke difference between the left and right parallel double pump plungers are adjusted and set at the wellhead. This, combined with the gear and rack mechanism, ensures that neither pump will collide during the alternating pumping process, while also meeting the maximum stroke requirement. After the entire device is lowered to the predetermined pump depth with the tubing string, the wellhead tubing hanger is set up, and the sucker rod string with the upper half of the universal pump disconnector (connecting sleeve) is lowered until it successfully impacts and connects with the lower half of the disconnector (butt joint) and automatically locks in place.

[0033] During the pumping process of the sucker rod string, the rack and pinion rod drives the pump plunger to alternately lift up and down. When the left plunger is at bottom dead center, the right plunger is at top dead center. When the left plunger begins to rise, the right plunger begins to descend, and this cycle repeats to achieve alternating lifting. Because the parallel dual pumps are rigidly connected to the tubing string via threaded connections, when the left plunger rises, the plunger's traveling valve closes, reducing the liquid column load on the left pump barrel. Conversely, when the right plunger descends synchronously, the plunger's traveling valve opens, increasing the liquid column load on the right pump barrel. Since the parallel dual pumps have identical specifications, structure, and stroke, the magnitude of the liquid column load increase and decrease during the pumping process is exactly equal. For example, when the left pump barrel reduces the liquid column load by 30kN, the right pump barrel simultaneously increases the liquid column load by 30kN, and vice versa. In this way, the entire tubing string experiences almost simultaneous equal increases and decreases in load, with the forces canceling each other out, and the tubing string effectively no longer bears the alternating liquid column load. Moreover, because the two parallel pumps on the left and right are seamlessly connected and synchronously alternate in and out of the well, the function of continuous drainage at the wellhead is realized.

[0034] While the design principle of this invention theoretically eliminates the equivalent alternating load of the liquid column on the tubing string, vibration and inertial loads still exist during the pumping process of the entire mechanical well. Furthermore, considering the slight differences in filling degree and liquid volume between the left and right pump barrels during fluid intake and discharge when the well supply is insufficient, the alternating load of the liquid column on the tubing may still exist at a relatively low value in actual operation. However, compared to traditional lifting systems, this invention exhibits an extremely low alternating load. This significantly reduces or even completely avoids contact fatigue damage at the tubing thread connections, reduces the number of wells lying down due to tubing thread leakage, and lowers the maintenance costs of mechanically operated wells.

[0035] In this embodiment, the gear assembly support is connected to the upper coupling 15 of the double pump via the connecting rod 7. Each gear assembly support includes a lower gear support 9 and an upper gear support 10 connected in sequence. The upper gear support 10 and the lower gear support 9 are respectively provided with rack rod mounting holes A and connecting rod mounting holes B for the two rack rods to pass through, a central flow hole C and a circumferential flow hole D. A gear bracket 18 and a drive gear 17 mounted on the gear bracket are provided between the upper gear support and the lower gear support.

[0036] To reduce the stress on each drive gear and extend the service life of the entire system, this embodiment includes two sets of gear assembly supports. Specifically, the two sets of gear assembly supports are coaxial and arranged in a vertically mirror-symmetrical configuration. The two rack tie rods are arranged horizontally and horizontally in a parallel and symmetrical configuration, and the two connecting rods and connecting rod nuts are arranged front-to-back in a parallel and mirror-symmetrical configuration.

[0037] A combined pipe 13 is provided between the two gear assembly supports. The upper ends of the two parallel oil pumps are connected to the lower gear support 9 at the bottom end via a double pump connecting section 16, a double pump upper coupling 15, and a double pump upper connector 14, from bottom to top. The lower gear support 9, the upper gear support 10, and the double pump upper coupling 15 all have the same coaxial multi-hole structure on their axes, namely, they are respectively provided with a rack tie rod mounting hole A, a connecting rod mounting hole B, a central flow hole C, and a circumferential flow hole D. To ensure that holes A, B, C, and D on each component (… Figure 5 As shown, all components can ensure that the axes of the corresponding holes are collinear. Each component is connected by end face contact. Sealing grooves are provided on the mating end faces of the gear lower support 9, gear upper support 10, combined pipe 13, double pump upper connector 14, and double pump upper coupling 15. Sealing steel rings 11 are arranged in the sealing grooves. The sealing steel rings 11 are pressed by connecting rods to achieve overall sealing of the assembly.

[0038] Furthermore, depending on the plunger's pumping load, by extending the length of the rack tie rod, a third or fourth set, or even more sets, of gear assembly supports can be added axially to evenly distribute the pumping load on the two rack tie rods, reduce the force on each transmission gear, and extend the service life of the entire system.

[0039] In this embodiment, the threaded end of the upper gear lower support 9 is connected to the double tie rod working cylinder 1, and the double tie rod working cylinder 1 is connected to the pump upper oil pipe. The threaded end of the lower gear lower support 9 is connected to the threaded end of the double pump upper connector 14. The other end of the double pump upper connector 14 is pressed and connected to the end face of the double pump upper coupling through the end face sealing steel ring 11. This ensures that the threaded hole connecting the double pump upper coupling and the left and right pump cylinder connecting short sections can be coaxially assembled with the left and right rack tie rods.

[0040] In this embodiment, the D holes evenly distributed around the circumference of the entire device are suction flow holes, and the central C hole is also a suction flow hole. The axis is directly opposite the drive gear. The suction flow can also lubricate and cool the gear, thus extending the service life of the device.

[0041] In this embodiment, both the lower gear support 9 and the upper gear support 10 are provided with gear brackets 18 by welding, riveting or inlaying. The mating surface of the gear brackets is provided with a bayonet structure to achieve positioning and limiting assembly.

[0042] In this embodiment, the specific structure of the two small-diameter oil pumps arranged in parallel on the left and right is shown in the figure. They include a left pump barrel 24, a plunger 26 connected to the corresponding left rack and pinion 12, an upstream moving valve 25, a downstream moving valve 27, and a fixed valve 28. The right oil pump has the same structure, including a pump barrel 32, a plunger 30 connected to the right rack and pinion 6, an upstream moving valve 29, a downstream moving valve 31, and a fixed valve 33. Below the fixed valve, they can be connected together to form a liquid inlet device through a variable thread connector, that is, a tailpipe string oil pipe can be used.

[0043] After the entire system is lowered to the predetermined pump depth in the well along with the tubing, a sucker rod string with a bottom-mounted release sleeve is lowered into the tubing. The release sleeve and the release joint connected to the eccentric rod head impact to achieve automatic limiting connection. Then, after being raised to a certain anti-surge distance, the sucker rod string drives the rack and pinion rod to achieve a synchronous, alternating lifting and pumping action of one rod and two pumps. When it is necessary to retrieve the sucker rod, first rotate and reverse the release sleeve and the release joint according to the release sleeve technical standards to allow for normal sucker rod retrieval.

[0044] During construction, two small-diameter oil pumps are introduced into the well in parallel and connected to each other via a double-pump upper connector 14, a double-pump upper coupling 15, and a pump barrel connecting section 16. They are symmetrically connected to the bottom of the lower gear support 9. The two pump plungers are also connected in parallel to two parallel rack rods. The two rack rods pass parallel to each other from bottom to top through the lower gear support 9, the upper gear support 10, the combined pipe 13, the upper gear support 10, and the lower gear support 9, respectively, and mesh with the drive gears 17 located between the lower gear support 9 and the upper gear support 10, forming a gear and rack mechanism. The lower gear support 9, the upper gear support 10, and the drive gear form a set of gear assembly supports, and the two sets of gear assembly supports are symmetrically arranged with their upper and lower axes aligned. One of the rack tie rods is connected to the extended tie rod 4 via tie rod coupling 5. The top of the extended tie rod 4 is connected to the eccentric rod head 2 and the rod head cap 3. The coupling 19 of the universal oil pump disconnector is connected above the eccentric rod head 2.

[0045] After the entire system is lowered to the predetermined pump depth in the well along with the tubing, the sucker rod string 23 with a bottom-mounted release sleeve 20 is lowered into the tubing. The release sleeve 20 is connected to the sucker rod string 23 via the release connector 21 and the sucker rod coupling 22. The release sleeve 20 impacts the release connector joint 19 connected to the eccentric rod head 2 to achieve automatic limiting connection. Then, after being raised to a certain anti-surge distance, the sucker rod string 23 can drive the rack and pinion rods 6 and 12 to achieve a synchronous, alternating lifting and pumping action of one rod and two pumps. When it is necessary to retrieve the sucker rod, first rotate and reverse the release sleeve and the joint according to the release connector technical standards to achieve normal sucker rod retrieval.

[0046] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A single-pump, dual-pump synchronously driven, alternating, continuous, ultra-low alternating load deep-lifting system, characterized in that, The system includes a double-pull-rod working cylinder, a gear assembly support, and two parallel oil pumps. The upper end of the gear assembly support is connected to the double-pull-rod working cylinder, and the lower end is connected to the two parallel oil pumps via double-pump couplings. Inside the double-pull-rod working cylinder are two parallel rack rods. The upper end of one rack rod is eccentrically connected to a sucker rod. The lower ends of the two rack rods pass parallel to each other through the gear assembly support and the corresponding two parallel oil pumps, and then connect with the two sucker rods. The pump plunger is connected to the oil pump. Two racks are fixed on the rack tie rods for meshing with gears installed in the gear assembly support. The gear assembly support has a flow hole. The gear assembly support is connected to the upper coupling of the dual pumps via a connecting rod. Each gear assembly support includes a lower gear support and an upper gear support connected in sequence. The upper and lower gear supports are symmetrically provided with rack tie rod mounting holes, connecting rod mounting holes, and flow holes for the two rack tie rods to pass through. A gear support and a gear mounted on the gear support are provided between the base and the lower gear support. This includes two coaxial gear assembly supports arranged in a mirror-symmetrical manner. A combined pipe is provided between the two gear assembly supports. The upper ends of the two parallel oil pumps are connected to the lower gear support at the bottom via a double-pump connecting section, a double-pump upper coupling, and a double-pump upper connector, sequentially from bottom to top. The lower gear support, upper gear support, and double-pump upper coupling all have the same coaxial multi-hole structure on their axes, i.e., each has a rack. The tie rod mounting hole, connecting rod mounting hole, and flow hole are provided with sealing grooves on the mating end faces of the gear lower support, gear upper support, combined pipe, double pump upper connector, and double pump upper coupling. A sealing steel ring is arranged in the sealing groove. The sealing steel ring is pressed by the connecting rod in series to achieve overall sealing of the assembly. The threaded end of the upper gear lower support is connected to the double tie rod working cylinder, and the double tie rod working cylinder is connected to the pump upper oil pipe. The threaded end of the lower gear lower support is connected to the threaded end of the double pump upper connector.

2. The single-pump, dual-pump synchronous drive, alternating continuous discharge, ultra-low alternating load deep extraction and lifting system according to claim 1, characterized in that, The double-pull working cylinder, combined pipe, and double pump upper connector are all coaxial hollow cylindrical structures.

3. The single-pump, dual-pump synchronous drive alternating continuous discharge ultra-low alternating load deep extraction lifting system according to claim 1, characterized in that, The flow passage is installed on the circumferential surface of the entire device.

4. The single-pump, dual-pump synchronous drive alternating continuous discharge ultra-low alternating load deep extraction lifting system according to claim 1, characterized in that, Both the lower gear support and the upper gear support are equipped with gear brackets by welding, riveting, or inlay. The mating surfaces of the gear brackets are equipped with bayonet structures to achieve positioning and limiting assembly.

5. The single-pump, dual-pump synchronous drive alternating continuous discharge ultra-low alternating load deep extraction lifting system according to claim 1, characterized in that, Two oil pumps are arranged in parallel on the left and right sides. The fixed valves of the oil pumps are connected together to form a single inlet device via a variable coupling.

6. The single-pump, dual-pump synchronous drive alternating continuous discharge ultra-low alternating load deep extraction lifting system according to claim 1, characterized in that, One of the rack and pinion rods is connected to the extended rod via a rod coupling. The top of the extended rod is connected to the eccentric rod head and rod head cap. The sucker rod is connected above the eccentric rod head.

7. The single-pump, dual-pump synchronous drive, alternating continuous discharge, ultra-low alternating load deep extraction and lifting system according to claim 6, characterized in that, The eccentric rod head is connected to the disconnector connector. The sucker rod string is connected to the disconnector coupling cylinder through the sucker rod coupling and the disconnector connector. The disconnector coupling cylinder impacts the disconnector connector connected to the eccentric rod head to achieve automatic limiting connection.

8. The single-pump, dual-pump synchronous drive alternating continuous discharge ultra-low alternating load deep extraction lifting system according to claim 1, characterized in that, The two parallel oil pumps have identical specifications, structure, and stroke.

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