Fracturing pump hydraulic end pressure control device and assembly

Abstract

The present invention relates to the technical field of fracturing pump manufacturing, and in particular to a hydraulic end pressure control device and assembly of a fracturing pump. A balancing tank is vertically arranged, and the lower end is connected to a liquid distribution pipe, so that pressure control is performed by the dead weight of water. A buffer chamber and a control chamber are arranged, and an isolation control device is arranged between the buffer chamber and the control chamber. The water level rises and falls in the buffer chamber to avoid flowing into the control chamber. Under high pressure, the buffer chamber is isolated from the control chamber, so that the buffer chamber is in a high pressure state, so as to ensure that the pressure in the liquid distribution tank is stable. An elastic bag is connected to a tension control structure to ensure the expansion force of the elastic bag and improve the pressure control effect of the elastic bag. The elastic bag is connected to the control chamber, and an exhaust port is connected to the upper end of the control chamber, so that the volume of the elastic bag can be smaller after contraction. The control chamber and the isolation control device are distributed at the upper end, so as to reduce the interference of assembly vibration and avoid the introduction of driving structures such as air pumps.

Description

Technical Field

[0001] The invention relates to the technical field of fracturing pump manufacturing, and in particular to a hydraulic end pressure control device and an assembly of a fracturing pump. Background Art

[0002] Fracturing pumps are widely used in oil field exploitation, natural gas development, geothermal energy utilization, groundwater exploitation and other fields. They are particularly important for oil extraction. They inject high-pressure liquid into underground rock formations to expand and connect the cracks in the formations, thereby improving the permeability and production of oil and gas.

[0003] The hydraulic end of the fracturing pump is the core component for transmitting pressure, which mainly includes a valve box, usually a three-cylinder or five-cylinder valve box, which continuously and stably provides high-pressure fracturing agent to destroy underground rock formations. The fracturing pump has a long working time, large flow rate and high power. Therefore, it needs to be finely controlled during use to detect multiple parameters, including flow rate, vibration, temperature and pressure, etc. Among them, pressure control includes pressure control at the high-pressure end and pressure control at the low-pressure end. The pressure control at the high-pressure end mainly includes a high-pressure end pressure sensor and a pressure control valve group. The pressure range of the high-pressure end is usually between 10MPa and 100MPa. The pressure control at the low-pressure end mainly includes a low-pressure end pressure sensor, a booster pump and a balance tank. The pressure range of the low-pressure end is usually between 0.2MPa and 0.5MPa, which can ensure flow stability and reduce cavitation. At the same time, the booster pump selects a variable frequency pump to adjust the booster pump flow according to the detection parameters.

[0004] The balancing tank includes a horizontal balancing tank and a vertical balancing tank. The balancing tank is connected to the low-pressure end manifold and includes a tank body. There is a pressure buffer chamber in the tank body. The pressure buffer chamber is composed of an air bag or a piston chamber. Pressure is buffered by the contraction and expansion of the air bag or the piston chamber. Since the fracturing pump is a high-flow pump, the pressure is controlled by the air bag, and the expansion and contraction capacity of the air bag is limited. The piston of the piston chamber is usually large in size and occupies a large space. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a hydraulic end pressure control device and assembly for a fracturing pump.

[0006] The present invention is realized through the following technical scheme: a hydraulic end pressure control device of a fracturing pump, comprising a low-pressure end pressure control module and a high-pressure end pressure control module, the low-pressure end pressure control module comprising a liquid distribution pipe, the liquid distribution pipe is connected to a water source through a booster pump, the high-pressure end pressure control module comprises a pressure limiting valve, the liquid distribution pipe is connected to a pressure balancing device, the pressure balancing device comprises a balancing tank, the balancing tank is vertically arranged, the balancing tank comprises a buffer chamber and a control chamber arranged in sequence from bottom to top, an isolation control device is arranged between the buffer chamber and the control chamber, the isolation control device comprises an isolation support plate, an elastic bag is arranged at the upper end of the buffer chamber, the elastic bag is connected to the control chamber, the elastic bag is connected to a tension control structure, the upper end of the control chamber is connected to an exhaust port, the elastic bag comprises a support plate with an opening upward, the upper end of the elastic bag is connected to a sealing ring, the sealing ring is connected to an upward guide sleeve, the guide sleeve can pass through the isolation support plate,

[0007] The tension control structure includes an elastic member arranged between the support disk and the sealing ring.

[0008] Furthermore, a fitting sealing structure is provided between the sealing ring and the isolation support plate, and the elastic bag is connected with the control cavity through a guide sleeve.

[0009] Furthermore, the support plate is connected with a cable, the cable extends into the control cavity and is connected with a balancer, and the tension control structure also includes a counterweight body arranged in the support plate.

[0010] Furthermore, a guide head with an arc-shaped cross section is arranged at the upper end of the guide sleeve, the arc top of the guide head faces upward, an air hole is arranged on the guide head, and the cable passes through the guide head upward.

[0011] Furthermore, a limiting sealing structure cooperating with the elastic bag is arranged in the buffer cavity, and the limiting sealing structure includes a sealing plate, a liquid outlet cooperating with the elastic bag is arranged on the sealing plate, and a sealing gasket cooperating with the liquid outlet is arranged at the lower end of the elastic bag.

[0012] Furthermore, a swing balance structure is provided at the lower end of the elastic bag, and the swing balance structure includes a weighted ball, and the weighted ball is connected to the elastic bag through a suspension rope.

[0013] Furthermore, a bracket matching with the weighted ball is arranged on the lower side of the sealing plate.

[0014] Furthermore, the elastic bag is in a stepped shape.

[0015] An assembly including a hydraulic end pressure control device for a fracturing pump.

[0016] The beneficial effects of the present invention are:

[0017] 1. The balance tank is arranged vertically, and the lower end is connected with the liquid distribution pipe, and then the pressure is controlled by the dead weight of the water. A buffer chamber and a control chamber are arranged, and an isolation control device is arranged between the buffer chamber and the control chamber. The water level rises and falls in the buffer chamber to avoid flowing into the control chamber. Under high pressure, the buffer chamber is isolated from the control chamber, so that the buffer chamber is in a high pressure state, thereby ensuring the stability of the pressure in the liquid distribution tank. The elastic bag is connected to the tension control structure, thereby ensuring the expansion force of the elastic bag and improving the pressure control effect of the elastic bag. The elastic bag is connected to the control chamber, and the upper end of the control chamber is connected with an exhaust port, which can make the elastic bag smaller in volume after contraction. The control chamber and the isolation control device are distributed at the upper end, thereby reducing the interference of assembly vibration and avoiding the introduction of driving structures such as air pumps;

[0018] 2. The elastic bag includes a support plate with an opening upward, a sealing ring, a guide sleeve, and an elastic member. The support plate and the sealing ring are separated by the elastic member, thereby expanding the elastic bag. When the pressure in the buffer chamber increases, the support plate pushes the elastic member upward to compress, thereby shrinking the elastic bag as a whole and replenishing water in the buffer chamber. When the pressure in the buffer chamber decreases, the support plate drives the elastic bag to descend as a whole, and the sealing ring is separated from the isolation support plate, thereby connecting the buffer chamber with the control chamber to avoid negative pressure. The elastic bag floats on the liquid surface, and the gravity of the elastic bag is partially converted into water pressure, thereby increasing the water pressure. A balancer is provided to adjust the gravity of the elastic bag acting on the liquid surface, and to guide the guide head, thereby enabling the guide head to stably pass through the isolation support plate, and the sealing ring and the isolation support plate are sealed;

[0019] 3. A limiting sealing structure matched with the elastic bag is arranged in the buffer cavity, thereby limiting the descent of the elastic bag and forming a seal while limiting the position to prevent air from entering the liquid distribution pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural schematic diagram of Example 1;

[0021] Figure 2 This is a cross-sectional diagram of the balance tank;

[0022] Figure 3 This is a schematic diagram of the main cross-section of the isolation control device;

[0023] Figure 4 is a schematic cross-sectional view of a support plate;

[0024] Figure 5 This is a schematic diagram of the main cross-section of the guide sleeve;

[0025] Figure 6 A top view of the guide sleeve is shown in FIG.

[0026] Among them: 1. valve box; 2. pressure limiting valve; 3. distribution pipe; 4. water inlet pipe; 5. water inlet valve; 6. high-pressure outlet pipe; 7. balance tank; 701. buffer chamber; 702. control chamber; 703. isolation support plate; 704. exhaust port; 705. filter; 706. detection tube; 707. pressure sensor; 708. balancer support frame; 709. balancer; 710. support plate; 711. cable; 712. spring; 713. elastic bag; 714. counterweight ball; 715. sealing plate; 716. bracket; 717. counterweight body; 718. suspension rope; 719. sealing ring; 720. guide sleeve; 721. guide head; 722. air hole; 723. sealing gasket; 724. reinforcing rib; 725. connecting column; 726. connecting sleeve; 727. connecting head; 728. sealing ring. DETAILED DESCRIPTION

[0027] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The following will be combined with the drawings in the embodiments of the invention to clearly and completely describe the technical solutions in the embodiments of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of the embodiments. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0029] Example 1

[0030] like Figure 1-6 As shown, a hydraulic end pressure control device of a fracturing pump includes a low-pressure end pressure control module and a high-pressure end pressure control module, wherein the high-pressure end pressure control module includes a pressure limiting valve 2, which releases pressure when the pressure exceeds the threshold of the pressure limiting valve 2, and the high-pressure end is connected to the high-pressure outlet pipe 6 to perform fracturing operations.

[0031] The low-pressure end pressure control module includes a liquid distribution pipe 3, which is connected to a water source through a water inlet pipe 4 and a booster pump. The water inlet pipe 4 is connected to a water inlet valve 5. The water inlet valve 5 selects an electrically controlled valve, and the flow rate can be controlled by controlling the opening of the water inlet valve 5. The booster pump selects a variable frequency pump, and the flow rate of the booster pump is adjusted according to the detection parameters. The water pressure of the liquid distribution pipe 3 is increased by the booster pump to between 0.2MPa and 0.5MPa, thereby ensuring the stability of the water inlet pressure and flow of the valve box 1.

[0032] By detecting the water pressure at the low-pressure end and controlling the action of the booster pump, the water pressure at the low-pressure end can be adjusted, but there is a time delay. In order to ensure timely control of the water pressure at the low-pressure end, technicians in this field install a balancing tank at the water inlet end of the distribution pipe 3. The existing balancing tank includes a horizontal balancing tank and a vertical balancing tank. The balancing tank 7 is connected to the distribution pipe 3, including a tank body, and a pressure buffer chamber is arranged in the tank body. The pressure buffer chamber is composed of an air bag or a piston chamber, and the pressure is buffered by the contraction and expansion of the air bag or the piston chamber. Since the fracturing pump is a high-flow pump, the pressure is controlled by the air bag, and the expansion and contraction capacity of the air bag is limited. The piston of the piston chamber is usually large in size and occupies a large space. In order to solve this technical problem, in this embodiment, the distribution pipe 3 is connected with a pressure balancing device, and the pressure balancing device includes a balancing tank 7. The balancing tank 7 is installed vertically. The balancing tank 7 includes a buffer chamber 701 and a control chamber 702 installed from bottom to top. An isolation control device is installed between the buffer chamber 701 and the control chamber 702. The isolation control device includes an isolation support plate 703. The upper end of the buffer chamber 701 is installed There is an elastic bag 713, which is connected to the control chamber 702. The upper end of the control chamber 702 is connected to the exhaust port 704. The lower end of the balance tank 7 is connected to the liquid distribution pipe 3, and then the pressure is controlled by the dead weight of the water. An isolation control device is installed between the buffer chamber 701 and the control chamber 702. The water level rises and falls in the buffer chamber 701 to avoid flowing into the control chamber 702. Under high pressure, the buffer chamber 701 is isolated from the control chamber 702, so that the buffer chamber 701 is in a high pressure state, thereby ensuring the pressure in the liquid distribution tank. Stable, the elastic bag 713 is connected to the tension control structure, thereby ensuring the expansion force of the elastic bag 713 and improving the pressure control effect of the elastic bag 713. The elastic bag 713 is connected to the control chamber 702. The upper end of the control chamber 702 is connected with an exhaust port 704, which can make the elastic bag 713 smaller in volume after contraction. The outer end of the exhaust port 704 is connected to a filter 705. The control chamber 702 and the isolation control device are distributed at the upper end, thereby reducing the interference from the vibration of the assembly, avoiding the introduction of driving structures such as air pumps, and further improving the working stability.

[0033] In this embodiment, the elastic bag 713 is made of fluororubber with a thickness of 6 mm. The lower end of the elastic bag 713 wraps the support plate 710 with an opening upward. The support plate 710 is stamped from a stainless steel plate with a thickness of 4 mm. The edge height of the support plate 710 is 40 mm. The support plate 710 and the elastic bag 713 are connected by a polyurethane adhesive, so that a stable sealing connection can be achieved. In order to improve the anti-deformation stability of the support plate 710, a reinforcing rib 724 is welded and fixed at the bottom of the support plate 710. A sealing ring 719 is connected to the upper end of the elastic bag 713. The sealing ring 719 is connected to an upward guide sleeve 720. The sealing ring 719 is made of stainless steel with a thickness of 6 mm. The wall thickness of the guide sleeve 720 is 3 mm. The sealing ring 719 The guide sleeve 720 is integrally formed with the guide sleeve 720, and the guide sleeve 720 can pass through the isolation support plate 703. Specifically, the isolation support plate 703 is made of a steel plate with a thickness of 8 mm and is rust-proofed. A guide opening that matches the guide sleeve 720 is processed on the isolation support plate 703. The inner diameter of the guide opening is 8-10 mm larger than the outer diameter of the guide sleeve 720. A guide head 721 with an arc-shaped cross section is integrally formed on the upper end of the guide sleeve 720. The arc top of the guide head 721 faces upward, so that the guide sleeve 720 can enter the guide opening more stably. There is a fitting sealing structure between the sealing ring 719 and the isolation support plate 703. The fitting sealing structure is a sealing ring 728. The sealing ring 728 is made of silicone, and the upper end face is inclined. The sealing ring 728 and the The guide sleeve 720 fits well, thereby guiding the sealing ring 719, and is partially squeezed into the gap between the guide sleeve 720 and the guide opening during sealing to improve the sealing effect. The elastic capsule 713 is connected to the control chamber 702 through the guide sleeve 720. The tension control structure includes an elastic member installed between the support plate 710 and the sealing ring 719. The elastic member is a spring 712. Since the elastic capsule 713 is made of fluororubber with a thickness of 6 mm, it has good elasticity. The tension can be further increased by the spring 712. The support plate 710 is connected to a cable 711. The cable 711 extends into the control chamber 702 and is connected to a balancer 709. A balancer support frame 708 is installed in the control chamber 702. The device 709 can adjust the torque to balance the gravity of the elastic bag 713, the support plate 710 and the sealing ring 719. The tension control structure also includes a counterweight body 717 arranged in the support plate 710. The counterweight body 717 is arranged in the gap of the reinforcing rib 724. The counterweight body 717 can be block-shaped or granular. The guide head 721 is processed with an air hole 722. The cable 711 passes through the guide head 721 upward. The guide head 721 is processed with a guide hole coaxial with the guide sleeve 720. The cable 711 passes through the guide hole. The gap between the cable 711 and the guide hole is matched, thereby ensuring that the cable 711 can slide along the guide hole and guide the guide head 721 at the same time, so that the guide head 721 can stably enter the guide opening.

[0034] In this embodiment, the elastic bag 713 is stepped, and the outer diameter of the elastic bag 713 close to the upper side is smaller, thereby ensuring that the elastic bag 713 shrinks inward during the contraction process, and the elastic bag 713 is in a compressed state with the support plate 710 and the sealing ring 719, thereby improving the sealing performance and avoiding separation from each other. A limiting sealing structure that cooperates with the elastic bag 713 is installed in the buffer cavity 701, and the limiting sealing structure includes a sealing plate 715, and a liquid outlet that cooperates with the elastic bag 713 is processed on the sealing plate 715. A sealing gasket 723 that cooperates with the liquid outlet is installed at the lower end of the elastic bag 713. In this embodiment, the sealing gasket 723 is a rubber gasket, and the portion where the sealing plate 715 cooperates with the sealing gasket 723 is in an upward arc shape, thereby improving the anti-deformation ability, and the descent of the elastic bag 713 is limited by the limiting sealing structure, and a seal is formed while limiting the position to prevent air from entering the distribution pipe 3.

[0035] During the test, it was found that when the pressure in the buffer chamber 701 reached between 0.2MPa and 0.5MPa, the sealing ring 719 and the isolation support plate 703 were sealed, and the elastic capsule 713 was in a compressed state. When the pressure in the buffer chamber 701 decreased, the liquid level in the buffer chamber 701 dropped, and the elastic capsule 713 dropped under the action of gravity. The sealing ring 719 was separated from the isolation support plate 703, and the elastic capsule 713 always floated on the liquid surface, thereby causing the liquid level to rise. The gravity of the elastic capsule 713 Part of it is converted into water pressure, thereby increasing the water pressure. When the elastic bag 713 floats, due to the disturbance of the liquid surface, the elastic bag 713 swings. A swing balance structure is connected to the lower end of the elastic bag 713. The swing balance structure includes a weighted ball 714. The weighted ball 714 is connected to the elastic bag 713 through a suspension rope 718. Under the action of the liquid surface disturbance, the weighted ball 714 and the elastic bag 713 form a mutual swing inhibition, thereby improving the stability of the elastic bag 713, avoiding collision and interference with the side wall of the buffer chamber 701, and thus making the elastic bag 713 The elastic bag 713 is stable during the rising process, and the guide sleeve 720 is stably inserted into the guide opening. In order to ensure the connection stability, a connecting column 725 is integrally stamped and formed at the middle position of the lower end of the support plate 710. The upper end of the connecting column 725 is connected to the connecting sleeve 726 through an external thread, and the connecting sleeve 726 is connected to the cable 711. The lower end of the connecting column 725 is connected to the connecting head 727 through an internal thread, and the connecting head 727 is connected to the suspension rope 718. The elastic bag 713 opens at the position corresponding to the connecting head 727, thereby avoiding To avoid interference, since the connection area between the elastic bag 713 and the support plate 710 is large, the opening has little effect on the sealing stability between the elastic bag 713 and the support plate 710. In order to prevent the counterweight ball 714 from entering the liquid distribution pipe 3, a bracket 716 matching the counterweight ball 714 is installed on the lower side of the sealing plate 715. The bracket 716 is made of a perforated plate and has a downward arc cross-section. When the elastic bag 713 is matched with the sealing plate 715, the counterweight ball 714 is supported by the bracket 716, which can prevent the counterweight ball 714 from swinging.

[0036] The buffer chamber 701 is connected to a pressure sensor 707 . Specifically, the pressure sensor 707 is connected to the buffer chamber 701 through a detection tube 706 , so that the pressure sensor 707 can be installed outside for easy maintenance.

[0037] The hydraulic end pressure control device of the fracturing pump provided in this embodiment is used in a normal state. During use, the pressure in the buffer chamber 701 is controlled between 0.2MPa and 0.5MPa. The sealing ring 719 is sealed with the isolation support plate 703. The elastic capsule 713 is in a compressed state. When the pressure sensor 707 detects low pressure, the booster pump is controlled to increase the flow rate, the pressure in the buffer chamber 701 increases, the elastic capsule 713 is compressed, and then the booster pump is controlled to reduce the flow rate. The pressure in the buffer chamber 701 gradually decreases, and the elastic capsule 713 expands. When the pressure sensor 707 detects low pressure again, the booster pump is controlled to increase the flow rate to meet the low pressure. The stability of water supply at the pressure end. Since the fracturing pump is a large-flow pump, a larger elastic bag 713 is required to meet the buffering requirements, and the installation space of the balance tank 7 is limited. When the booster pump cannot replenish enough water in time, the liquid level in the buffer chamber 701 drops, and the elastic bag 713 drops under the action of gravity. The sealing ring 719 is separated from the isolation support plate 703, and the elastic bag 713 always floats on the liquid surface, thereby causing the liquid level to rise. The gravity part of the elastic bag 713 is converted into water pressure, thereby increasing the water pressure and providing buffer time for the action of the booster pump. During the test, it was also found that when a larger balloon is used to provide buffering, when the balance When the pressure in the tank 7 is low, continuing to reduce the pressure requires overcoming the elastic force of the balloon itself, so that the pressure in the balance tank 7 drops rapidly. In this embodiment, the elastic bag 713 drops to connect the buffer chamber 701 with the control chamber 702, and then connects to the outside through the exhaust port 704. The pressure drop in the buffer chamber 701 is stable. When the elastic bag 713 drops to cooperate with the sealing plate 715, it will no longer continue to drop, thereby preventing air from entering the liquid distribution pipe 3. At this time, wait for the pressure in the buffer chamber 701 on the lower side of the elastic bag 713 to increase, and the liquid level pushes the elastic bag 713 to rise, or shut down for maintenance. To meet the use requirements, control the booster pump to increase It is a fast process to increase the pressure in the buffer chamber 701 by increasing the flow rate, which is completed within 5 seconds. The liquid level in the buffer chamber 701 rises rapidly, and accordingly, the elastic bag 713 rises rapidly. The counterweight ball 714 can weaken the swing of the elastic bag 713, and the air in the buffer chamber 701 is discharged from the guide opening. When the sealing ring 728 contacts the isolation support plate 703, the sealing effect is unstable and the exhaust can continue. When the elastic bag 713 continues to rise and pushes the spring 712 to press the sealing ring 728 and the isolation support plate 703 to seal, the exhaust ends, the pressure in the buffer chamber 701 increases rapidly, and the elastic bag 713 begins to be compressed.

[0038] An assembly including a hydraulic end pressure control device of a fracturing pump controls the pressure at the low pressure end through the hydraulic end pressure control device of the fracturing pump, thereby ensuring a stable flow and reducing cavitation.

[0039] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A hydraulic end pressure control device for a fracturing pump, comprising a low-pressure end pressure control module and a high-pressure end pressure control module, wherein the low-pressure end pressure control module comprises a liquid distribution pipe, the liquid distribution pipe is connected to a water source through a booster pump, the high-pressure end pressure control module comprises a pressure limiting valve, the liquid distribution pipe is connected to a pressure balancing device, the pressure balancing device comprises a balancing tank, and is characterized in that: The balancing tank is arranged vertically, and comprises a buffer chamber and a control chamber arranged in sequence from bottom to top, an isolation control device is arranged between the buffer chamber and the control chamber, and the isolation control device comprises an isolation support plate, an elastic bag is arranged at the upper end of the buffer chamber, the elastic bag is connected to the control chamber, the elastic bag is connected to a tension control structure, and an exhaust port is connected to the upper end of the control chamber, The elastic bag comprises a support plate with an opening upward, a sealing ring is connected to the upper end of the elastic bag, and the sealing ring is connected to an upward guide sleeve, and the guide sleeve can pass through the isolation support plate. The tension control structure includes an elastic member arranged between the support disk and the sealing ring.

2. The hydraulic end pressure control device of a fracturing pump according to claim 1, characterized in that: A fitting sealing structure is provided between the sealing ring and the isolation support plate, and the elastic bag is communicated with the control cavity through a guide sleeve.

3. The hydraulic end pressure control device of the fracturing pump according to claim 2, characterized in that: The support plate is connected with a cable, the cable extends into the control cavity and is connected with a balancer, and the tension control structure also includes a counterweight body arranged in the support plate.

4. The hydraulic end pressure control device of a fracturing pump according to claim 3, characterized in that: The upper end of the guide sleeve is provided with a guide head with an arc-shaped cross section, the arc top of the guide head faces upward, an air hole is provided on the guide head, and the cable passes through the guide head upward.

5. The hydraulic end pressure control device of a fracturing pump according to claim 4, characterized in that: A position limiting sealing structure cooperating with the elastic bag is arranged in the buffer cavity, and the position limiting sealing structure comprises a sealing plate, a liquid outlet cooperating with the elastic bag is arranged on the sealing plate, and a sealing pad cooperating with the liquid outlet is arranged at the lower end of the elastic bag.

6. The hydraulic end pressure control device of the fracturing pump according to claim 5, characterized in that: A swing balance structure is arranged at the lower end of the elastic bag. The swing balance structure comprises a weighted ball. The weighted ball is connected to the elastic bag through a suspension rope.

7. The hydraulic end pressure control device of the fracturing pump according to claim 6, characterized in that: A bracket matched with the weight ball is arranged on the lower side of the sealing plate.

8. The hydraulic end pressure control device of a fracturing pump according to claim 7, characterized in that: The elastic bag is in a stepped shape.

9. An assembly comprising the hydraulic end pressure control device of a fracturing pump according to any one of claims 1 to 8.

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