A fracturing plunger pump for oil fields

Abstract

The present application relates to the technical field of fracturing pump, and provides a fracturing plunger pump for high-low pressure conversion of oil field, which comprises an outer shell body, a main control platform for processing pressure data inside the fracturing plunger pump and outputting control signals is installed at the front end of the outer shell body, a pressure cylinder is installed at the rear end inside the outer shell body, a pressure measuring collection port is installed at the top end of the pressure cylinder to collect pressure data inside the pressure cylinder, so as to analyze the pressure environment inside the pressure cylinder in cooperation with the main control platform. The rapid switching of high-low pressure mode of the fracturing plunger pump is realized. The transmission shaft is displaced to switch the transmission ratio of the speed change wheel set through the gear shifting assembly, and the advancing distance of the pressurizing plunger is controlled in cooperation with the adjusting assembly, so that the pressurizing pressure size is accurately adjusted. The low pressure mode is suitable for conventional liquid injection fracturing, and the high pressure mode can meet the high pressure requirements of sand carrying fracturing, fracture forming and proppant delivery.

Description

Technical Field

[0001] This invention relates to the field of fracturing pump technology, specifically to a fracturing plunger pump for high-low pressure conversion in oil fields. Background Technology

[0002] A plunger pump relies on the reciprocating motion of a plunger within a cylinder to change the volume of a sealed working chamber, thereby achieving liquid intake and discharge and ensuring that the discharged liquid has a certain pressure. Typically, a plunger pump consists of an eccentric wheel, a plunger, a cylinder, and two check valves. A sealed working chamber is formed between the plunger and the cylinder bore. The two check valves respectively enable one-way water intake and one-way water discharge. One rotation of the eccentric wheel drives the plunger to reciprocate once, achieving liquid intake and discharge.

[0003] A search revealed a composite transmission device for a fracturing plunger pump, publication number CN108443099B. This device includes a housing, a hydraulic torque converter, a planetary reduction mechanism, a friction brake assembly, a comprehensive control valve, a reduction mechanism II, and an electric actuator. The hydraulic torque converter comprises an input shaft I, a triple-supply pump, a synchronizing ring, a guide wheel, a turbine, a turbine shaft, and a pump impeller. The sun gear of the planetary reduction mechanism is coaxially driven by the turbine shaft, and the gear ring contacts and separates from the friction plates in the friction brake assembly under hydraulic control. The planetary carrier of the planetary reduction mechanism connects to and drives the input shaft II of the reduction mechanism II. The comprehensive control valve includes a valve body, a relief valve core, and a solenoid valve. The electric actuator drives a shift fork via a lead screw linkage mechanism and a synchronizing ring. The shift fork drives the adjustable guide wheel blades to rotate around its own axis. This device, through its novel structural design, solves the problem of the lack of a dedicated transmission device for fracturing plunger pumps in the existing technology, and has significant technical implications.

[0004] The background information of the aforementioned patents mentions that in complex geological conditions, fracturing operations involve frequent pump pressure fluctuations and numerous impact loads. To ensure fracturing operation safety and prevent the fracturing pump from overpressured, a common approach is to use a programmed linkage mode where the diesel engine slows down and the transmission downshifts. This mode has poor adaptability and cannot meet the demands of continuous high-pressure operations. Therefore, in existing technologies, plunger fracturing pumps need to adjust their high and low pressure at appropriate times based on the working environment to adapt to different operational requirements. Thus, a fracturing plunger pump for high and low pressure switching in oilfields is needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a fracturing plunger pump for high-low pressure switching in oil fields, solving the problem that plunger fracturing pumps need to adjust high and low pressure at appropriate times according to the working environment to adapt to different working requirements.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A fracturing plunger pump for high-low pressure switching in oil fields, comprising: The outer casing has a main control platform installed at its front end for processing internal pressure data and output control signals of the fracturing plunger pump. A pressure cylinder is installed at the rear end of the outer casing. A pressure measurement and acquisition port installed at the top of the pressure cylinder collects pressure data inside the pressure cylinder to cooperate with the main control platform in analyzing the pressure environment inside the pressure cylinder, thereby controlling the high and low pressure output switching of the fracturing plunger pump. An inlet and outlet valve group for liquid entry and exit is installed inside the rear end of the pressure cylinder to cooperate with the hydraulic fracturing work in the oil field. A support base is fixedly connected to the inner middle of the outer shell. A power component is installed on the front side of the support base. The power component converts torque into a reciprocating force to drive the force-applying shaft on its rear side to reciprocate. A pressure plunger is slidably connected to the rear side of the force-applying shaft to drive the pressure plunger at the rear end of the force-applying shaft to pressurize and depressurize inside the pressure cylinder. An adjustment component is provided between the force-applying shaft and the pressure plunger to control the advancing distance of the pressure plunger and thus control the pressure. The pressure plunger slides back and forth in the sliding part of the support base and is supported by the support base. The housing has a power shaft rotatably connected to one end inside, which is driven by a motor. The other end of the housing has a transmission shaft, and a gearbox is connected between the power shaft and the transmission shaft. The transmission shaft is displaced by a shifting assembly installed at one end to switch the transmission ratio of the gearbox. The other end of the transmission shaft is connected to the power assembly. The shifting assembly and the adjustment assembly are connected by a worm gear. A suction cylinder is installed on the top side of the outer casing. A trigger unit is installed on the front side of the piston end of the suction cylinder. The trigger unit is triggered by an abutment installed on the top side of the power assembly to move the piston end of the suction cylinder back and forth, causing the suction cylinder to draw lubricating oil into the oil tank installed at its input end. The output end of the suction cylinder is connected to an oil dripping pipe through a pipeline. Both the input and output ends of the suction cylinder are equipped with one-way valve diaphragms. The oil dripping pipe is fixedly connected to the front side of the support base to drip oil into the oil groove opened on the outer wall of the force-applying shaft, thereby reducing the sliding resistance of the force-applying shaft on the support base. A collection trough is formed inside the support base. The top of the collection trough is connected to the sliding area provided by the support base for the force-applying shaft. An oil drain port is fixedly connected to one side of the bottom of the collection trough. A pressure cylinder for providing pressurization is installed on the front side of the bottom of the oil drain port. The pressure cylinder, together with the sealing component on the top side, forms a sealed space inside the collection trough. Waste lubricating oil is discharged from the oil drain port by pressurization. The input end of the pressure cylinder penetrates the outer wall of the support base and the outer shell. The output end of the pressure cylinder is located at the bottom of the inside of the collection trough. Both the input and output ends of the pressure cylinder are equipped with one-way valve diaphragms. A pull-out component is installed on the piston end of the pressure cylinder. The pull-out component is triggered by the abutment on the bottom side of the power component.

[0007] Preferably, the inlet / outlet valve assembly includes multiple valve balls, the pressure cylinder has multiple pressurizing chambers inside, the pressurizing plunger is slidably connected to the front end of the pressurizing chamber, the rear tops of the multiple pressurizing chambers are connected, and both sides of the rear tops of the multiple pressurizing chambers are fixedly connected to liquid outlets, the rear bottoms of the multiple pressurizing chambers are connected, and both sides of the rear bottoms of the multiple pressurizing chambers are fixedly connected to liquid inlets, half of the valve balls are located at the rear tops of the multiple pressurizing chambers, and the other half of the valve balls are located at the rear bottoms of the multiple pressurizing chambers, the top of the valve ball slides vertically to the interior of the pressurizing chamber through a spring, and the bottom of the valve ball is located at the communication port inside the pressurizing chamber.

[0008] Preferably, the power assembly includes a power roller, which is rotatably connected to the inner front end of the outer casing. A reduction planetary gear set is installed on one side of the power roller. The input end of the reduction planetary gear set is connected to the other end of the transmission shaft through a splined shaft and splined sleeve, which engages with two meshing bevel gears. Multiple eccentric frames are rotatably connected to the middle end of the power roller. The eccentric frames rotate on non-concentric shafts with the power roller. The rotating part of the eccentric frame is located on the outer circumference of the center of the power roller. The rear end of the eccentric frame is rotatably connected to the front side of the oil tank. There are two abutment joints, which are fixedly connected to the top side of the two eccentric frames on both sides. The abutment joint is fixedly connected to the bottom side of the middle eccentric frame.

[0009] Preferably, the adjusting assembly includes a connecting frame, which is fixedly connected to the front end of the pressurizing plunger. A contact ring is slidably connected to the front end of the connecting frame, and the contact ring is fixedly connected to the rear end of the force-applying shaft. A limiting ring slides horizontally at the middle end of the connecting frame, and the limiting ring is threadedly connected to a screw that rotates on the bottom side of the connecting frame. A shaped shaft is inserted inside the screw, and a worm gear is fixedly connected to the rear end of the shaped shaft. A worm is meshed with the bottom sides of multiple worm gears, and a worm wheel is fixedly connected to one side of the worm. The top side of the worm wheel meshes with the worm.

[0010] Preferably, the gear set includes a meshing gear one and a gear two, the gear one and gear two having different sizes and specifications, and there are two of each gear one and gear two. Both gear one and gear two are rotatably connected to the inner wall of the housing, and the relative positions of the two gear one and the two gear two are axially symmetrical. The power shaft is fixedly connected to the middle of one of the gear one and one of the gear two. The transmission shaft is sleeved on the middle of the other gear one and the other gear two. Engaging shims are fixedly connected to the adjacent side of the other gear one and the other gear two. Engaging wheels are fixedly connected to the outer wall of the transmission shaft, and the engaging wheels engage with one of the engaging shims.

[0011] Preferably, the shifting assembly includes a displacement frame rotatably connected to one end of the transmission shaft, the top side of the displacement frame sliding horizontally with the housing, a motor mounted on one side of the worm gear two, a screw gear two fixedly connected to the other side of the worm gear two, the screw gear two rotatably connected to the outer wall of the housing, and the bottom end of the displacement frame threadedly connected to the screw gear two.

[0012] Preferably, the trigger unit includes two upper abutment frames that are vertically slidably connected to the top side of the outer casing. The bottom end of the upper abutment frame is located on the top side of the abutment head one. The two upper abutment frames are connected to a connecting rod one on adjacent sides through a one-way transmission wheel set. The rear end of the connecting rod one is rotatably connected to the piston end of the suction cylinder.

[0013] Preferably, the unidirectional transmission wheel set includes two rotating frames. The bottom side of the rotating frame is fixedly connected to the top side of the outer casing. An input wheel is rotatably connected to one side of the rotating frame, and an output shaft is rotatably connected to the other side of the rotating frame. The outer periphery of the two output shafts on adjacent sides is rotatably connected to a connecting rod. The outer periphery of one side of the input wheel slides against the guide groove at the top of the upper abutment frame through a guide protrusion. A ratchet is fixedly connected to the other side of the input wheel. An embedded ring is fixedly connected to the side of the output shaft near the input wheel. The outer periphery of the embedded ring is slidably connected to a meshing tooth through a spring piece, and the meshing tooth abuts against the ratchet.

[0014] Preferably, the sealing assembly includes a sealing plate and a suspension frame fixedly connected to the bottom end of the outer wall of the support base. The sealing plate is slidably connected to the bottom end of the support base by a spring. One end of the sealing plate is located on one side of the collection groove, and the other end of the sealing plate is fixedly connected to an offset head. An arc-shaped abutment is slidably mounted vertically on the bottom side of the suspension frame. The rear end of the arc-shaped abutment slides against the offset head. The bottom side of the arc-shaped abutment is arc-shaped and abuts against the top side of the piston end of the pressure cylinder.

[0015] Preferably, the pull-out assembly includes a lower abutment frame, which is located on the bottom side of the abutment joint and connected to the inner bottom side of the outer shell through a spring telescopic rod. A second connecting rod is rotatably connected to the rear side of the lower abutment frame, and the rear end of the second connecting rod is rotatably connected to the piston end of the pressure cylinder.

[0016] Working principle: When carrying out fracturing work in an oil field, the fracturing plunger pump is started through the main control platform; First, the wellbore pre-filling, pressure testing, and pre-fluid injection are carried out in low-pressure mode. The motor drives the power shaft in the housing, which in turn drives the meshing shims that mesh with the meshing wheel in low-pressure mode through the meshing gears 1 and 2. The meshing wheel drives the transmission shaft to rotate. At this time, the meshing gears 1 and 2 are speed-increasing transmissions. The transmission shaft drives the reduction planetary gear set through the spline shaft and spline sleeve in conjunction with two meshing bevel gears. After the reduction planetary gear set converts the torque, it drives the power roller to rotate. When the power roller rotates, the eccentric frame connected to it performs reciprocating eccentric motion, causing the force-applying shaft on the rear side of the eccentric frame to move back to its original position. In low-pressure mode, when the force-applying shaft moves forward, the limiting ring and the abutting ring are at their maximum distance. When the force-applying shaft moves forward, the sliding between the force-applying shaft and the pressurizing plunger takes priority, causing the advancing distance of the force-applying shaft to be consumed until the force-applying shaft and the abutting ring move forward to the position of the limiting ring at the end. At this time, the pressurizing plunger is subjected to force and advances. Compared with high-pressure mode, the shorter compression distance results in a smaller compressed space volume inside the pressure cylinder, resulting in a smaller applied pressure. When the force-applying shaft is pulled backward, the force-applying shaft first slides on the pressurizing plunger. When it is pulled to the limit distance, it drives the pressurizing plunger to reset. After completing the work in low-pressure mode, the high-pressure mode is switched. The motor drives worm two and screw two connected to worm two. The rotating worm two rotates through meshing transmission with worm wheel two connected to worm one, causing worm one to mesh synchronously with worm wheel one connected to the irregular shaft. The irregular shaft transmits the rotation of screw one through the irregular cross-section shaft structure, causing screw one to drive the limiting ring frame to move and shorten the distance between the limiting ring frame and the abutting ring frame. The rotating screw two drives the displacement frame to move through the thread transmission, causing the transmission shaft connected to the displacement frame to move, and move together with the meshing wheel one, and mesh with another meshing pad. Through another set of gear one and gear two, the transmission is reduced in speed. Subsequently, the sand-carrying fracturing, fracture creation, and proppant delivery work are carried out in high-pressure mode. The motor drives the power shaft in the housing, which in turn drives the meshing pads that mesh with the meshing wheel in high-pressure mode through the meshing gears 1 and 2. This causes the meshing wheel to drive the transmission shaft to rotate. At this time, the meshing gears 1 and 2 are for deceleration transmission, repeating the action logic of the force-applying shaft in low-pressure mode. In high-pressure mode, when the force-applying shaft moves forward, the limiting ring and the abutting ring are at their minimum distance. When the force-applying shaft moves forward, the extension and retraction between the force-applying shaft and the pressurizing plunger will be canceled, and the forward movement distance of the force-applying shaft will no longer be consumed. The force-applying shaft, together with the abutting ring, will move directly to the position of the limiting ring at the end. At this time, the pressurizing plunger will be subjected to force, and the extended compression distance compared to the low-pressure mode will increase the compressed space capacity inside the pressure cylinder, thereby increasing the applied pressure. When the force-applying shaft is pulled backward, the force-applying shaft will directly pull the pressurizing plunger to reset. In both high-pressure and low-pressure modes, when the pressurizing plunger is advanced in the support seat, the valve ball at the top of the pressurizing chamber is pushed up by the pressurized liquid in the pressurizing chamber, compressing the spring connected to it. The pressurized liquid is discharged from the outlet and then reset. When the pressurizing plunger is pulled in and out of the support seat, a negative pressure is generated in the space of the pressurizing chamber, making the pressure on the top side of the valve ball at the bottom of the pressurizing chamber less than the pressure on the bottom side. It is then pushed open by the hydraulic pressure from the inlet on the bottom side, allowing the liquid to enter the pressurizing chamber of the support seat. The above pressurization operation is repeated to input pressurized liquid into the oil and gas reservoir of the oil field, causing the oil and gas reservoir to collapse and improving the production and extraction efficiency of the oil field. During the pressurization process, the pressurization chamber is monitored by the pressure acquisition port on the top side of the support base. The pressure data after the pressurized liquid is output is collected and transmitted back to the analysis system of the main control platform for monitoring and analysis. If the pressure increase rate inside the pressurization chamber is abnormal after pressurization output due to the reaction generated inside the pressurization chamber, it is determined that the pressurized oil and gas layer is blocked. At this time, in order to ensure pressurization efficiency, it is changed to low-pressure slow pressurization to reduce the reaction force caused by high pressure and damage to the equipment. During the pressurized conveying process, the support seat, which serves as a support, provides auxiliary support to the force-applying shaft. The force-applying shaft slides back and forth in the sliding support area provided by the support seat. In order to minimize the sliding resistance and avoid energy loss, the sliding area needs to be lubricated. During the eccentric transmission process, the abutment joints on the top sides of two eccentric frames and the abutment joint on the bottom side of one of the eccentric frames will deviate along the trajectory of the eccentric frame. The abutment joint intermittently abuts against the upper abutment frame on the top side, causing the upper abutment frame to rise and then return to its original position under gravity. During the rising process, the upper abutment frame pulls the input wheel to rotate forward through the guide groove and the guide protrusion on the input wheel, causing it to engage with the meshing teeth on the insert ring via ratchet teeth. The forward-rotating meshing teeth are limited by the tooth-like structure on the ratchet teeth, causing the meshing teeth to work with the insert ring to drive the output shaft to rotate. When the upper abutment frame falls and pulls the input wheel to return to its original position, the reverse rotation of the input wheel causes the ratchet teeth to rotate in reverse, causing the inclined surface of the ratchet tooth-like structure to follow the inclined surface of the meshing teeth. The ratchet slides and causes the meshing teeth to retract into the embedded ring, compressing the spring. It then resets, preventing the ratchet from meshing with the meshing teeth. This prevents the upper abutment frame from rotating the output shaft when it falls, resulting in unidirectional rotation. The output shaft then drives the connecting rod connected to it to perform eccentric motion, repeatedly pushing and pulling the piston end of the suction cylinder. This causes the suction cylinder to draw a fixed amount of lubricating oil from inside the oil tank and deliver it through a pipeline to the dripping pipe. The lubricating oil drips from the dripping pipe onto the oil groove of the force-applying shaft and wraps around the area along the path of the oil groove, sliding in the sliding area of ​​the support seat. When the oil tank is inside the sliding area of ​​the support, the lubricating oil deteriorates under high temperature and friction. When it accumulates excessively, it falls into the opening of the collection tank and the sliding part of the support, causing the deteriorated lubricating oil to accumulate in the collection tank. The abutment joint intermittently abuts against the lower abutment frame at the bottom, causing the lower abutment frame to press down and pull the connecting rod two to push. The piston end of the pressure cylinder, which is pushed, first abuts against the arc-shaped abutment joint and is lifted. Through the guide groove of the offset head, it drives the sealing plate connected to the offset head to move, causing the sealing plate to insert into the bottom of the collection tank and form a sealing area with the bottom side of the collection tank. At this time, the air inside the pressure cylinder is injected into the sealed space from the output end to pressurize it. This causes the deteriorated lubricating oil in the sealed space to be quickly discharged from the oil outlet under the influence of pressure, preventing it from thickening due to excessive accumulation. The lower abutment frame is reset by the spring telescopic rod on the bottom side, which, together with the structure including the piston end of the pressure cylinder, resets, allowing the pressure cylinder to re-draw air to the outside through the input end.

[0017] This invention provides a fracturing plunger pump for high-low pressure switching in oil fields. It has the following beneficial effects: 1. This invention enables rapid switching between high and low pressure modes in a fracturing plunger pump. The transmission shaft shifts the gear ratio of the gearbox via a shifting assembly, and the adjusting assembly controls the advance distance of the pressurized plunger, thereby precisely adjusting the pressurization pressure. The low-pressure mode is suitable for conventional hydraulic fracturing, while the high-pressure mode can meet the high-pressure requirements of proppant fracturing, fracture creation, and proppant delivery.

[0018] 2. This invention enables continuous oil supply to the sliding area of ​​the force-applying shaft, effectively reducing the sliding friction resistance between the force-applying shaft and the support seat, reducing energy loss and component wear caused by friction, extending the service life of key moving parts, and ensuring long-term stable operation of the equipment.

[0019] 3. This invention avoids the long-term accumulation and thickening of waste oil inside the equipment, preventing waste oil pollution from affecting the normal operation of the equipment. It achieves this by creating a sealed space. A pressurizing cylinder injects air into this sealed space, using air pressure to quickly discharge waste lubricating oil from the drain port, thus maintaining a clean environment inside the equipment.

[0020] 4. This invention can analyze and process the pressure environment and output control signals to automatically drive the shifting and adjusting components to complete the high and low pressure mode conversion, making pressure control more precise and response more timely. It effectively avoids damage to equipment and oil and gas reservoirs caused by overpressure or underpressure, improves the safety and reliability of oilfield fracturing operations, and realizes intelligent fracturing control. Attached Figure Description

[0021] Figure 1 This is a perspective view of the present invention; Figure 2 This is a schematic diagram of the back-end structure of the present invention; Figure 3 This is a schematic diagram of the internal structure of the outer shell of the present invention; Figure 4 This is a schematic diagram of the connection structure of the power roller of the present invention; Figure 5 This is a schematic diagram of the connection structure of the force-applying shaft of the present invention; Figure 6 This is a schematic diagram of the connecting frame of the present invention; Figure 7 This is a schematic diagram of the connection structure of the worm gear II of the present invention; Figure 8 This is a schematic diagram of the internal structure of the base shell of the present invention; Figure 9 This is a schematic diagram showing the position of the abutment of the present invention; Figure 10 This is a schematic diagram of the connection structure of the first connecting rod of the present invention; Figure 11 This is a schematic diagram of the rotating frame of the present invention; Figure 12 This is a schematic diagram showing the position of the ratchet teeth in this invention; Figure 13 This is a schematic diagram of the embedded ring structure of the present invention; Figure 14 This is a schematic diagram of the collection tank of the present invention; Figure 15This is a schematic diagram of the connection structure of the second connecting rod of the present invention; Figure 16 This is a schematic diagram of the arc-shaped abutment of the present invention; Figure 17 This is a schematic diagram of the pressure cylinder of the present invention.

[0022] The components include: 1. Outer shell; 2. Support base; 3. Pressure cylinder; 4. Reduction planetary gear set; 5. Power roller; 6. Eccentric frame; 7. Force application shaft; 8. Pressure plunger; 9. Oil tank; 10. Connecting frame; 11. Screw one; 12. Limiting ring frame; 13. Abutment ring frame; 14. Irregular shaft; 15. Worm gear one; 16. Worm one; 17. Worm gear two; 18. Worm two; 19. Housing; 20. Power shaft; 21. Transmission shaft; 22. Engaging wheel; 23. Engaging shim; 24. Gear one; 25. Gear two; 26. Displacement frame; 27. Screw two; 28. 1. Connector 1; 29. ​​Upper Connector Frame; 30. Rotating Frame; 31. Input Wheel; 32. Output Shaft; 33. Connecting Rod 1; 34. Suction Cylinder; 35. Oil Tank; 36. Drip Pipe; 37. Embedded Ring; 38. Engaging Tooth; 39. Ratchet; 40. Collection Tank; 41. Oil Drain Port; 42. Connector; 43. Lower Connector Frame; 44. Connecting Rod 2; 45. Pressure Cylinder; 46. Suspension Frame; 47. Arc-shaped Connector; 48. Offset Head; 49. Sealing Plate; 50. Liquid Inlet; 51. Liquid Outlet; 52. Valve Ball; 53. Pressure Measurement and Acquisition Port; 54. Main Control Platform. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0024] This invention provides a fracturing plunger pump for high-low pressure switching in oil fields, comprising: Please see the appendix Figure 1 - Appendix Figure 3The outer casing 1 has a main control platform 54 installed at its front end for processing internal pressure data and output control signals of the fracturing plunger pump. The main control platform 54 is configured with corresponding functional modules according to production needs. Both the hardware and software configurations are capable of handling the corresponding production processes. The pressure cylinder 3 is installed at the rear end of the outer casing 1. The pressure measurement and acquisition port 53 installed at the top of the pressure cylinder 3 collects the pressure data inside the pressure cylinder 3 to cooperate with the main control platform 54 in analyzing the pressure environment inside the pressure cylinder 3, and then controlling the output high and low pressure conversion of the fracturing plunger pump. The rear end of the pressure cylinder 3 is equipped with an inlet and outlet valve group for liquid entry and exit to cooperate with the hydraulic fracturing work in the oil field. Specifically, all specifications of this fracturing plunger pump meet market equipment standards, and it possesses adequate sealing and robustness, thus possessing the basic functions of common fracturing plunger pumps on the market to handle oilfield fracturing operations. During pressurization, the pressurization chamber is monitored by the pressure acquisition port 53 on the top side of the support 2, collecting pressure data after the pressurized liquid is output. This pressure data is transmitted back to the analysis system of the main control platform 54 for monitoring and analysis. If the pressure increase rate inside the pressurization chamber is abnormal after pressurization output due to the reaction force generated inside the pressurization chamber, it is determined that the pressurized oil and gas layer is obstructed. At this time, in order to ensure pressurization efficiency, it is switched to low-pressure slow pressurization to reduce the reaction force caused by high pressure and reduce damage to the equipment. At the same time, the corresponding power structure is speed-adjusted to adapt to the change in pressurization distance after the high-low pressure conversion, so as to avoid efficiency loss.

[0025] Please see the appendix Figure 2 Appendix Figure 3 and attached Figure 17 The inlet and outlet valve assembly includes multiple valve balls 52. The pressure cylinder 3 has multiple pressurizing chambers inside. The pressurizing plunger 8 is slidably connected to the front end of the pressurizing chamber. The top of the rear end of the multiple pressurizing chambers is connected, and the top of the rear end of the multiple pressurizing chambers is fixedly connected to both sides of the top of the rear end of the multiple pressurizing chambers. The bottom of the rear end of the multiple pressurizing chambers is connected, and the bottom of the rear end of the multiple pressurizing chambers is fixedly connected to both sides of the bottom of the rear end of the multiple pressurizing chambers. Half of the valve balls 52 are located at the top of the rear end of the multiple pressurizing chambers, and the other half of the valve balls 52 are located at the bottom of the rear end of the multiple pressurizing chambers. The top of the valve ball 52 slides vertically with the inside of the pressurizing chamber through a spring, and the bottom of the valve ball 52 is located at the communication port inside the pressurizing chamber. Specifically, in both high-pressure and low-pressure modes, when the pressurizing plunger 8 is advanced in the support seat 2, the valve ball 52 at the top of the pressurizing chamber is lifted by the pressurized liquid in the pressurizing chamber, compressing the spring connected to it. The pressurized liquid is discharged from the outlet 51 and then resets. When the pressurizing plunger 8 is pulled in the support seat 2, a negative pressure is generated in the space of the pressurizing chamber, making the pressure on the top side of the valve ball 52 at the bottom of the pressurizing chamber less than the pressure on the bottom side. It is then pushed open by the hydraulic pressure from the inlet 50 on the bottom side, allowing the liquid to enter the pressurizing chamber of the support seat 2. The above pressurization operation is repeated to input pressurized liquid into the oil and gas layer of the oil field, causing the oil and gas layer to collapse and improving the production and extraction efficiency of the oil field.

[0026] Please see the appendix Figure 3 - Appendix Figure 5 The support base 2 is fixedly connected to the middle of the inner part of the outer shell 1. A power component is installed on the front side of the support base 2. The power component converts torque into a reciprocating force to drive the force-applying shaft 7 at its rear side to reciprocate. A pressure plunger 8 is slidably connected to the rear side of the force-applying shaft 7 to drive the pressure plunger 8 at the rear end of the force-applying shaft 7 to pressurize and depressurize inside the pressure cylinder 3. An adjustment component is provided between the force-applying shaft 7 and the pressure plunger 8 to control the advancing distance of the pressure plunger 8, thereby controlling the pressure. The pressure plunger 8 reciprocates in the sliding part of the support base 2 and is supported by the support base 2. The power component includes a power roller. 5. The power roller 5 is rotatably connected to the front end of the inner shell 1. A reduction planetary gear set 4 is installed on one side of the power roller 5. The input end of the reduction planetary gear set 4 is connected to the other end of the transmission shaft 21 through a spline shaft and spline sleeve with two meshing bevel gears. Multiple eccentric frames 6 are rotatably connected to the middle end of the power roller 5. The eccentric frames 6 rotate on a non-concentric shaft with the power roller 5. The rotating part of the eccentric frame 6 is located on the outer circumference of the center of the power roller 5. The rear end of the eccentric frame 6 is rotatably connected to the front side of the oil tank 9. There are two abutment joints 28, which are fixedly connected to the top side of the two eccentric frames 6. The abutment joint 42 is fixedly connected to the bottom side of the middle eccentric frame 6. Specifically, the reduction planetary gear set 4 is a standard planetary gear-based structure available on the market, and it has a reduction mechanism to reduce torque force to combat mechanical fatigue and damage caused by excessive torque force. During wellbore pre-filling, pressure testing, and pre-fluid injection in low-pressure mode, the motor drives the power shaft 20 in the housing 19. The power shaft 20, through meshing gears 24 and 25, transmits power to the meshing pad 23, which meshes with the meshing wheel 22 in low-pressure mode. The meshing wheel 22 then drives the transmission shaft 21 to rotate. At this time, the meshing gears 24 and 25 provide speed-increasing transmission. The transmission shaft 21, through a splined shaft and splined sleeve, engages with two meshing bevel gears to transmit power to the reduction planetary gear set 4. After the reduction planetary gear set 4 converts the torque, it drives the power roller 5. When the power roller 5 rotates, the eccentric frame 6 connected to it performs reciprocating eccentric motion, causing the force shaft 7 on the rear side of the eccentric frame 6 to move back and forth, performing sand-carrying fracturing, fracture creation, and proppant delivery work in high-pressure mode. The motor drives the power shaft 20 in the housing 19, causing the power shaft 20 to transmit the meshing pad 23 that meshes with the meshing wheel 22 in high-pressure mode through the meshing gear 1 24 and gear 2 25, causing the meshing wheel 22 to drive the transmission shaft 21 to rotate. At this time, the meshing gear 1 24 and gear 2 25 are for deceleration transmission, repeating the action logic of the force shaft 7 in low-pressure mode.

[0027] Please see the appendix Figure 6 and attached Figure 7 The adjusting assembly includes a connecting frame 10, which is fixedly connected to the front end of the pressurizing plunger 8. The front end of the connecting frame 10 is slidably connected to an abutment ring frame 13, which is fixedly connected to the rear end of the force-applying shaft 7. The middle end of the connecting frame 10 is horizontally slidably connected to a limiting ring frame 12, which is threadedly connected to a screw 11 rotating on the bottom side of the connecting frame 10. A shaped shaft 14 is inserted inside the screw 11, and a worm gear 15 is fixedly connected to the rear end of the shaped shaft 14. A worm 16 is meshed on the bottom side of multiple worm gears 15, and a worm gear 17 is fixedly connected to one side of the worm gear 16. The top side of the worm gear 17 meshes with the worm gear 18. Specifically, when the equipment is in low-pressure mode, the limiting ring 12 and the abutting ring 13 are at their maximum distance when the force-applying shaft 7 moves forward. When the force-applying shaft 7 moves forward, the sliding between the force-applying shaft 7 and the pressure plunger 8 takes priority, causing the advancing distance of the force-applying shaft 7 to be consumed until the force-applying shaft 7 and the abutting ring 13 move forward to the position of the limiting ring 12 at the end. At this time, the pressure plunger 8 is subjected to force and the advancing distance is shorter than that in high-pressure mode. This results in a smaller compressed space volume inside the pressure cylinder 3, which in turn results in a smaller applied pressure. When the force-applying shaft 7 is pulled backward, the force-applying shaft 7 first slides on the pressure plunger 8. When it is pulled to the limit distance, it drives the pressure plunger 8 to reset. When the equipment is in high-pressure mode, the limiting ring 12 and the abutting ring 13 are at their minimum distance when the force-applying shaft 7 moves forward. When the force-applying shaft 7 moves forward, the extension and retraction between the force-applying shaft 7 and the pressurizing plunger 8 will be canceled. The advancing distance of the force-applying shaft 7 will no longer be consumed, allowing the force-applying shaft 7 to work with the abutting ring 13 to directly advance to the position of the limiting ring 12 at the end. At this time, the pressurizing plunger 8 will be subjected to force, resulting in an extended compression distance compared to the low-pressure mode. This expands the compressed space capacity inside the pressure cylinder 3, increasing the applied pressure. When the force-applying shaft 7 is pulled backward, it will directly drive the pressurizing plunger 8 to reset.

[0028] Please see the appendix Figure 4 Appendix Figure 7 and attached Figure 8 The housing 19 has a drive shaft 20 rotatably connected to one end inside, driven by a motor. A transmission shaft 21 is located at the other end of the housing 19. A gearbox is connected between the drive shaft 20 and the transmission shaft 21. The transmission shaft 21 is displaced by a shifting assembly installed at one end to switch the gear ratio of the gearbox. The other end of the transmission shaft 21 is connected to the power assembly. The shifting assembly and the adjustment assembly are connected by a worm gear 18. The gearbox includes two meshing gears, a first gear 24 and a second gear 25. Gears 24 and 25 are of different sizes, and there are two of each. Both gears 24 and 25 are rotatably connected to the inner wall of the housing 19, and the relative positions of the two first gears 24 and the two second gears 25 are... The positions are all axially symmetrical to each other. The power shaft 20 is fixedly connected to the middle of one of the gears 24 and one of the gears 25. The transmission shaft 21 is sleeved on the middle of another gear 24 and another gear 25. Engaging shims 23 are fixedly connected to the adjacent side of the other gear 24 and the other gear 25. Engaging wheels 22 are fixedly connected to the outer wall of the transmission shaft 21. Engaging wheels 22 engage with one of the engagement shims 23. The shifting assembly includes a displacement frame 26 rotatably connected to one end of the transmission shaft 21. The top side of the displacement frame 26 slides horizontally with the housing 19. A motor is installed on one side of the worm gear 18. A screw 27 is fixedly connected to the other side of the worm gear 18. The screw 27 is rotatably connected to the outer wall of the housing 19. The bottom end of the displacement frame 26 is threadedly connected to the screw 27. Specifically, during high-low pressure conversion, the motor drives the second worm gear 18 and the screw 27 connected to it. The rotating worm gear 18 rotates through a meshing transmission with the worm wheel 17 connected to the first worm gear 16, causing the first worm gear 16 to simultaneously mesh with the worm wheel 15 connected to the irregular shaft 14. The irregular shaft 14 then transmits the rotation of the screw 11 through its irregular cross-section shaft structure, causing the screw 11 to drive the displacement of the limiting ring frame 12, shortening the distance between the limiting ring frame 12 and the abutment ring frame 13. The rotating screw 27 then drives the displacement frame 26 through a threaded transmission, causing the transmission shaft 21 connected to the displacement frame 26 to shift, coordinating with the meshing wheel 22 to shift and mesh with another meshing pad 23, which is then transmitted through another set of gears 24 and 25. By adjusting the speed, the system adapts to changes in the advance distance of the pressurizing plunger 8, thereby maintaining the stability of the pressurizing output efficiency. Please see the appendix Figure 9 -Appendix Figure 11 The suction cylinder 34 is installed on the top side of the outer casing 1. A trigger unit is installed on the front side of the piston end of the suction cylinder 34. The trigger unit is activated by the abutment joint 28 installed on the top side of the power assembly, so as to drive the piston end of the suction cylinder 34 to move back and forth, causing the suction cylinder 34 to draw lubricating oil into the oil tank 35 installed at its input end. The output end of the suction cylinder 34 is connected to the drip pipe 36 through the pipe. Both the input end and the output end of the suction cylinder 34 are equipped with one-way valve diaphragms, drip... Oil pipe 36 is fixedly connected to the front side of support base 2 for dripping oil into the oil groove 9 opened on the outer wall of force application shaft 7, so as to reduce the sliding resistance of force application shaft 7 on support base 2. The trigger unit includes two upper abutment frames 29 vertically slidably connected to the top side of outer shell 1. The bottom end of the upper abutment frame 29 is located on the top side of abutment head 28. The two upper abutment frames 29 are connected to a connecting rod 33 on the adjacent side through a one-way transmission wheel set. The rear end of the connecting rod 33 is rotatably connected to the piston end of suction cylinder 34. Specifically, during the pressurized conveying process, as the support seat 2 provides auxiliary support to the force-applying shaft 7, the force-applying shaft 7 slides back and forth in the sliding support area provided by the support seat 2. In order to minimize the sliding resistance and avoid energy loss, the sliding area needs to be lubricated. During the eccentric transmission process, the abutment joints 28 on the top side of two eccentric frames 6 and the abutment joint 42 on the bottom side of one of the eccentric frames 6 will deviate along the trajectory of the eccentric frame 6.

[0029] Please see the appendix Figure 11 -Appendix Figure 13The unidirectional drive wheel set includes two rotating frames 30. The bottom side of the rotating frame 30 is fixedly connected to the top side of the outer shell 1. An input wheel 31 is rotatably connected to one side of the rotating frame 30, and an output shaft 32 is rotatably connected to the other side of the rotating frame 30. The outer periphery of the two output shafts 32 on the adjacent side is rotatably connected to the connecting rod 33. The outer periphery of one side of the input wheel 31 slides against the guide groove at the top of the upper abutment frame 29 through a guide protrusion. A ratchet 39 is fixedly connected to the other side of the input wheel 31. An embedded ring 37 is fixedly connected to the side of the output shaft 32 near the input wheel 31. A meshing tooth 38 is slidably connected to the outer periphery of the embedded ring 37 through a spring piece. The meshing tooth 38 abuts against the ratchet 39. Specifically, the abutment joint 28 intermittently abuts against the upper abutment frame 29 on the top side, causing the upper abutment frame 29 to rise and then return to its original position under gravity. During the rising process, the upper abutment frame 29 will drive the input wheel 31 to rotate forward through the guide groove and the guide protrusion on the input wheel 31, causing it to engage with the meshing teeth 38 on the insert ring 37 via the ratchet 39. The forward-rotating meshing teeth 38 will be limited by the tooth-like structure on the ratchet 39, causing the meshing teeth 38 to work with the insert ring 37 to drive the output shaft 32 to rotate. When the upper abutment frame 29 falls and pulls the input wheel 31 to its original position, the reverse rotation of the input wheel 31 will cause the ratchet 39 to rotate in reverse, causing the inclined surface of the tooth-like structure of the ratchet 39 to follow the meshing direction. The inclined surface of tooth 38 slides, causing the meshing tooth 38 to retract into the embedded ring 37, compressing the spring, and then resetting, so that the ratchet 39 cannot mesh with the meshing tooth 38, so that the upper abutment frame 29 cannot drive the output shaft 32 to rotate when it falls, forming a unidirectional rotation, causing the output shaft 32 to drive the connecting rod 33 connected to it to perform eccentric motion, reciprocating and continuously pushing and pulling the piston end of the suction cylinder 34, thereby causing the suction cylinder 34 to draw a certain amount of lubricating oil from the oil tank 35, and transport it to the oil dripping pipe 36 through the pipeline. The lubricating oil drips along the oil dripping port of the oil dripping pipe 36 onto the oil receiving groove 9 of the force-applying shaft 7, and wraps around the area along the path of the oil receiving groove 9, and slides in the sliding area of ​​the support seat 2.

[0030] Please see the appendix Figure 14 - Appendix Figure 16A collection trough 40 is formed inside the support base 2. The top of the collection trough 40 is connected to the sliding area provided by the support base 2 for the force-applying shaft 7. An oil drain port 41 is fixedly connected to one side of the bottom end of the collection trough 40. A pressure cylinder 45 for providing pressure is installed on the front side of the bottom end of the oil drain port 41. The pressure cylinder 45, together with the sealing component on the top side, constructs a sealed space inside the collection trough 40. Waste lubricating oil is discharged from the oil drain port 41 by pressurization. The input end of the pressure cylinder 45 penetrates through the outer wall of the support base 2 and the outer shell 1, and the output end of the pressure cylinder 45 is located at the bottom end of the inside of the collection trough 40. Both the input and output ends of the pressure cylinder 45 are equipped with one-way valve diaphragms. A pull-out assembly is installed on the piston end of the pressure cylinder 45. The pull-out assembly is triggered by the abutment 42 on the bottom side of the power assembly. The sealing assembly includes a sealing plate 49 and a suspension bracket 46 fixedly connected to the bottom of the outer wall of the support base 2. The sealing plate 49 is slidably connected to the bottom of the support base 2 by a spring. One end of the sealing plate 49 is located on one side of the collection tank 40, and the other end of the sealing plate 49 is fixedly connected to an offset head 48. The suspension bracket 46... The bottom side of the device has an arc-shaped abutment 47 that slides vertically. The rear end of the arc-shaped abutment 47 slides against the offset head 48. The bottom side of the arc-shaped abutment 47 is arc-shaped and abuts against the top side of the piston end of the pressure cylinder 45. The pull-out assembly includes a lower abutment frame 43, which is located on the bottom side of the abutment 42 and is connected to the inner bottom side of the outer shell 1 through a spring telescopic rod. The rear side of the lower abutment frame 43 is rotatably connected to a second connecting rod 44, and the rear end of the second connecting rod 44 is rotatably connected to the piston end of the pressure cylinder 45. Specifically, when the oil reservoir 9 is inside the sliding area of ​​the support 2, the lubricating oil deteriorates under the action of high temperature and friction. When too much lubricating oil accumulates, it falls into the collection tank 40 and the opening of the sliding part of the support 2, causing the deteriorated lubricating oil to accumulate in the collection tank 40. The abutment 42 will intermittently abut against the lower abutment frame 43 at the bottom, causing the lower abutment frame 43 to press down and pull the connecting rod 44 to push. The piston end of the pressure cylinder 45, which is pushed, first abuts against the arc-shaped abutment 47 and is lifted. It is then driven and deflected by the guide groove of the offset head 48. The sealing plate 49 connected to the head 48 is displaced, causing the sealing plate 49 to be inserted into the bottom end of the collection tank 40, forming a sealing area with the bottom side of the collection tank 40. At this time, the air inside the pressure cylinder 45 is injected into the sealed space from the output end to pressurize it, thereby causing the deteriorated lubricating oil in the sealed space to be quickly discharged from the oil outlet 41 under the influence of pressure, avoiding the accumulation time of too long and thickening. The lower abutment frame 43 is reset by the spring telescopic rod on the bottom side, and the structure including the piston end of the pressure cylinder 45 is reset, thereby causing the pressure cylinder 45 to re-draw air to the outside through the input end.

[0031] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fracturing plunger pump for high-low pressure switching in oil fields, characterized in that, include: The outer shell (1) has a pressure cylinder (3) installed at the rear end inside the outer shell (1). The rear end of the pressure cylinder (3) is equipped with an inlet and outlet valve group for liquid entry and exit, in order to cooperate with the hydraulic fracturing work of the oil field. Support base (2), the support base (2) is fixedly connected to the middle of the inner part of the outer shell (1), a power component is installed on the front side of the support base (2), a force-applying shaft (7) is installed on the rear side of the power component, a pressure plunger (8) is slidably connected to the rear side of the force-applying shaft (7), an adjustment component is provided between the force-applying shaft (7) and the pressure plunger (8) to control the pressure applied by the pressure plunger (8), the pressure plunger (8) slides back and forth in the sliding part of the support base (2) and is supported by the support base (2); The housing (19) has a power shaft (20) rotatably connected to one end inside the housing (19). The power shaft (20) is driven by a motor. The other end of the housing (19) is provided with a transmission shaft (21). A gear set is connected between the power shaft (20) and the transmission shaft (21). The transmission shaft (21) is displaced by a shifting component installed at one end to switch the transmission ratio of the gear set. The other end of the transmission shaft (21) is connected to the power component. The shifting component and the adjustment component are connected by a worm gear (18). The suction cylinder (34) is installed on the top side of the outer shell (1). A trigger unit is installed on the front side of the piston end of the suction cylinder (34). The trigger unit is triggered by the abutment joint (28) installed on the top side of the power assembly, so that the suction cylinder (34) draws lubricating oil into the oil tank (35) installed at its input end. The output end of the suction cylinder (34) is connected to the drip pipe (36) through the pipe. The drip pipe (36) is fixedly connected to the front side of the support base (2) for dripping oil into the oil groove (9) opened on the outer wall of the force-applying shaft (7) to keep the sliding resistance of the force-applying shaft (7) on the support base (2) reduced. The collection trough (40) is located inside the support base (2). The top of the collection trough (40) is connected to the sliding area provided by the support base (2) for the force-applying shaft (7). An oil drain port (41) is fixedly connected to one side of the bottom end of the collection trough (40). A pressure cylinder (45) for providing pressure is installed on the front side of the bottom end of the oil drain port (41). The pressure cylinder (45) and the top sealing component together construct a sealed space inside the collection trough (40). Waste lubricating oil is discharged from the oil drain port (41) by pressurization. A pull-out component is installed on the piston end of the pressure cylinder (45). The pull-out component is triggered by the abutment (42) on the bottom side of the power component. The adjustment assembly includes a connecting frame (10), which is fixedly connected to the front end of the pressurizing plunger (8). The front end of the connecting frame (10) is slidably connected to an abutment ring frame (13), which is fixedly connected to the rear end of the force-applying shaft (7). The middle end of the connecting frame (10) is horizontally slidably connected to a limiting ring frame (12), which is threadedly connected to a screw (11) rotating on the bottom side of the connecting frame (10). A shaped shaft (14) is inserted inside the screw (11), and a worm gear (15) is fixedly connected to the rear end of the shaped shaft (14). A worm gear (16) is meshed with the bottom side of a plurality of worm gears (15), and a worm gear (17) is fixedly connected to one side of the worm gear (16). The top side of the worm gear (17) meshes with the worm gear (18). The shifting assembly includes a displacement frame (26) rotatably connected to one end of the transmission shaft (21). The top side of the displacement frame (26) slides horizontally with the housing (19). A motor is installed on one side of the worm gear (18), and a screw (27) is fixedly connected to the other side of the worm gear (18). The screw (27) is rotatably connected to the outer wall of the housing (19), and the bottom end of the displacement frame (26) is threadedly connected to the screw (27).

2. The fracturing plunger pump for high-low pressure switching in oil fields according to claim 1, characterized in that, The inlet / outlet valve assembly includes multiple valve balls (52). The pressure cylinder (3) has multiple pressurizing chambers inside. The pressurizing plunger (8) is slidably connected to the front end of the pressurizing chamber. The top rear ends of the multiple pressurizing chambers are connected together. Both sides of the top rear ends of the multiple pressurizing chambers are fixedly connected to liquid outlets (51). The bottom rear ends of the multiple pressurizing chambers are connected together. Both sides of the bottom rear ends of the multiple pressurizing chambers are fixedly connected to liquid inlets (50). Half of the valve balls (52) are located at the top rear ends of the multiple pressurizing chambers, and the other half of the valve balls (52) are located at the bottom rear ends of the multiple pressurizing chambers. The top end of the valve ball (52) slides vertically with the inside of the pressurizing chamber through a spring. The bottom end of the valve ball (52) is located at the communication port inside the pressurizing chamber.

3. A fracturing plunger pump for high-low pressure switching in oil fields according to claim 1, characterized in that, The power assembly includes a power roller (5), which is rotatably connected to the front end of the inner shell (1). A reduction planetary gear set (4) is installed on one side of the power roller (5). The input end of the reduction planetary gear set (4) is connected to the other end of the transmission shaft (21) through a spline shaft and spline sleeve with two meshing bevel gears. A plurality of eccentric frames (6) are rotatably connected to the middle end of the power roller (5). The eccentric frames (6) rotate on a non-concentric axis with the power roller (5). The rotating part of the eccentric frame (6) is located on the outer circumference of the center of the power roller (5). The rear end of the eccentric frame (6) is rotatably connected to the front side of the oil tank (9). There are two abutment joints (28), which are fixedly connected to the top side of the two eccentric frames (6). The abutment joint (42) is fixedly connected to the bottom side of the middle eccentric frame (6).

4. A fracturing plunger pump for high-low pressure switching in oil fields according to claim 1, characterized in that, The gear set includes a meshing gear one (24) and a gear two (25). The gear one (24) and gear two (25) are of different sizes. There are two of each gear one (24) and gear two (25). Both gear one (24) and gear two (25) are rotatably connected to the inner wall of the housing (19). The relative positions of the two gear one (24) and the two gear two (25) are axially symmetrical. The power shaft (20) is fixedly connected to... At the midpoint of one of the gears (24) and one of the gears (25), the transmission shaft (21) is sleeved at the midpoint of the other gear (24) and the other gear (25). Engaging pads (23) are fixedly connected to the adjacent side of the other gear (24) and the other gear (25). Engaging wheels (22) are fixedly connected to the outer wall of the transmission shaft (21). The engagement wheels (22) engage with one of the engagement pads (23).

5. A fracturing plunger pump for high-low pressure switching in oil fields according to claim 1, characterized in that, The trigger unit includes two upper abutment frames (29) that are vertically slidably connected to the top side of the outer casing (1). The bottom end of the upper abutment frame (29) is located on the top side of the abutment head (28). The two upper abutment frames (29) are connected to a connecting rod (33) on their adjacent sides via a one-way transmission wheel set. The rear end of the connecting rod (33) is rotatably connected to the piston end of the suction cylinder (34). The input and output ends of the suction cylinder (34) are both equipped with one-way valve diaphragms.

6. A fracturing plunger pump for high-low pressure switching in oil fields according to claim 5, characterized in that, The unidirectional transmission wheel set includes two rotating frames (30). The bottom side of the rotating frame (30) is fixedly connected to the top side of the outer shell (1). An input wheel (31) is rotatably connected to one side of the rotating frame (30), and an output shaft (32) is rotatably connected to the other side of the rotating frame (30). The outer periphery of the two output shafts (32) on the adjacent side is rotatably connected to the connecting rod (33). The outer periphery of one side of the input wheel (31) slides against the guide groove at the top of the upper abutment frame (29) through a guide protrusion. A ratchet (39) is fixedly connected to the other side of the input wheel (31). An embedded ring (37) is fixedly connected to the side of the output shaft (32) near the input wheel (31). A meshing tooth (38) is slidably connected to the outer periphery of the embedded ring (37) through a spring sheet. The meshing tooth (38) abuts against the ratchet (39).

7. A fracturing plunger pump for high-low pressure switching in oil fields according to claim 1, characterized in that, The sealing assembly includes a sealing plate (49) and a suspension bracket (46) fixedly connected to the bottom of the outer wall of the support base (2). The sealing plate (49) is slidably connected to the bottom of the support base (2) by a spring. One end of the sealing plate (49) is located on one side of the collection groove (40). The other end of the sealing plate (49) is fixedly connected to an offset head (48). An arc-shaped abutment (47) slides vertically on the bottom side of the suspension bracket (46). The rear end of the arc-shaped abutment (47) slides against the offset head (48). The bottom side of the arc-shaped abutment (47) is arc-shaped and abuts against the top side of the piston end of the pressure cylinder (45). The input end of the pressure cylinder (45) penetrates the outer wall of the support base (2) and the outer shell (1). The output end of the pressure cylinder (45) is located at the bottom of the inner end of the collection groove (40). Both the input end and the output end of the pressure cylinder (45) are equipped with a one-way valve diaphragm.

8. A fracturing plunger pump for high-low pressure switching in oil fields according to claim 1, characterized in that, The pull-out assembly includes a lower abutment frame (43), which is located on the bottom side of the abutment joint (42) and is connected to the inner bottom side of the outer shell (1) through a spring telescopic rod. A second connecting rod (44) is rotatably connected to the rear side of the lower abutment frame (43), and the rear end of the second connecting rod (44) is rotatably connected to the piston end of the pressure cylinder (45).

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