High-pressure large-flow long-acting hydraulic permeability pumping system for deep coal seam

Abstract

The present application relates to coal bed gas mining technical field, especially suitable for deep coal seam's high pressure big flow long effect hydraulicization permeability improvement pumping system, including: power end, for converting prime mover power into plunger reciprocating motion; hydraulic end, connecting power end, including self-reinforcing prestressed winding type ultrahigh pressure cylinder and self-adapting sealing liquid inlet and outlet valve, ceramic-metal composite plunger moves in cylinder to increase pressure for normal pressure water into ultrahigh pressure water flow; High pressure pipeline system, connecting hydraulic end outlet, including multilayer steel wire winding hose or thick wall steel pipe with pressure resistance not less than 150MPa and self-balancing high pressure sealing quick connector; Intelligent control system, for real-time monitoring pressure, flow, vibration and temperature parameters, and executing automatic pressure stabilization, overrun protection, fault early warning and soft start-stop. The present application system bears high pressure, key components have long service life, and runs stably and intelligently, which can provide reliable equipment foundation for deep coal seam large-scale fracturing.

Description

Technical Field

[0001] This invention relates to the field of coalbed methane extraction technology, and in particular to a high-pressure, high-flow-rate, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams. Background Technology

[0002] As coal mining in my country extends to deeper levels, deep coal seams generally exhibit characteristics such as high ground stress, high gas content, and low permeability. To ensure safe mining and efficient gas extraction, large-scale and long-term hydraulic fracturing of the coal seams is necessary to create a widespread fracture network and increase permeability. The core surface or underground equipment for implementing this technology is a high-flow-rate, ultra-high-pressure water pump unit, whose performance directly determines the scale, effectiveness, and timeliness of fracturing.

[0003] Currently, conventional water pump units used in deep coal seam fracturing face severe challenges during long-term continuous high-pressure operation. Their power-end components, such as crankshafts and frames, are prone to fatigue fracture under ultra-high alternating loads; critical hydraulic-end components, such as plungers, cylinder liners, and valve assemblies, wear rapidly and have short lifespans under high-pressure erosion environments; high-pressure pipeline systems lack reliability under severe pressure pulsation; and there is a lack of intelligent monitoring and closed-loop control of the equipment's own health status. These problems make it difficult for existing equipment to achieve long-term, continuous, stable, ultra-high flow rate pumping at pressure levels of 150 MPa and above. Frequent downtime and component replacements not only significantly increase operating costs but also severely restrict the engineering implementation of large-scale, high-efficiency hydraulic permeability enhancement technology in deep coal seams. Summary of the Invention

[0004] To overcome the above shortcomings, this invention provides a high-pressure, high-flow, long-lasting hydraulic fracturing pumping system suitable for deep coal seams. It aims to improve the problems of existing pumping equipment in deep coal seams under ultra-high pressure, high flow, and long-term continuous hydraulic fracturing conditions, where key components are easily damaged, operation is unstable, and reliability is poor, making it difficult to meet the needs of large-scale and efficient fracturing operations.

[0005] This invention provides the following technical solution, applicable to a high-pressure, high-flow-rate, long-lasting hydraulic permeability enhancement pumping system for deep coal seams, comprising: The power unit includes a high-strength alloy crankshaft and an integrated cast frame, which are used to convert the rotational power of the prime mover into the reciprocating linear motion power of the plunger. The hydraulic end, connected to the power end, includes a self-reinforcing prestressed winding ultra-high pressure cylinder and an inlet and outlet valve with an adaptive sealing structure. The plunger reciprocates within the ultra-high pressure cylinder to draw in atmospheric pressure water and pump it out as ultra-high pressure water. The plunger is a ceramic-metal composite plunger. A high-pressure pipeline system, connected to the outlet of the hydraulic end, includes a multi-layer steel wire wound hose or a thick-walled steel pipe and a self-balancing high-pressure sealing quick-connect coupling, for conveying the ultra-high pressure water flow; The intelligent control system is used to monitor the pressure, flow, vibration and temperature parameters of the power end, hydraulic end and high-pressure pipeline system in real time, and to perform automatic pressure stabilization control based on the pressure parameters, while also performing over-limit protection, fault warning and soft start-stop functions.

[0006] Preferably, the power end is a five-cylinder plunger pump power end, and the high-strength alloy crankshaft has cranks corresponding to the five plungers, and is made by heat treatment and surface strengthening processes to withstand ultra-high alternating loads. The integrated casting frame is a one-piece molded high-rigidity box structure, which integrates a main bearing housing for mounting the high-strength alloy crankshaft, a crosshead slide for guiding the piston movement, and an oil circuit for a forced circulation lubrication system.

[0007] Preferably, the power end also includes an optimized bearing system and a forced circulation lubrication system that are matched with the integrated casting frame.

[0008] Preferably, in the hydraulic end, the self-reinforcing prestressed wound ultra-high pressure cylinder body is formed by pre-applying reverse stress during manufacturing.

[0009] Preferably, the inlet and outlet valve with an adaptive sealing structure is configured to automatically adjust the sealing pressure ratio according to the working pressure.

[0010] Preferably, the self-balancing high-pressure sealing quick connector is configured to automatically compensate for alignment errors and achieve metal sealing during connection.

[0011] Preferably, the intelligent control system includes: Pressure sensors and flow sensors are used to collect the pressure parameters and flow parameters in real time; Vibration sensors and temperature sensors are respectively arranged at the main bearing seat of the high-strength alloy crankshaft in the power end, at the crosshead slide of the integrated casting frame, and at the outer wall of the self-reinforcing prestressed winding ultra-high pressure cylinder in the hydraulic end, for real-time acquisition of vibration parameters and temperature parameters. The controller is used to perform the automatic voltage regulation control, over-limit protection, fault warning and soft start-stop functions.

[0012] Preferably, the automatic voltage regulation control is achieved by adjusting the speed of the prime mover or the displacement of the pump through the controller.

[0013] Preferably, the fault warning is based on the analysis of vibration spectrum or temperature change trend, and provides early warning before the component suffers substantial damage.

[0014] Preferably, the rated pressure resistance of the multi-layer steel wire wound hose or thick-walled steel pipe is not less than 150 MPa.

[0015] The present invention has the following beneficial effects: 1. In this invention, by employing a high-strength alloy crankshaft and an integrated casting machine frame for the power end, along with a self-reinforcing prestressed wound ultra-high pressure cylinder, the fatigue strength and overall rigidity of the core pressure-bearing components are significantly improved from the structural source. Combined with multi-layer wound pipelines with a rated pressure resistance of not less than 150MPa and self-balancing sealing joints, the entire pumping system can stably withstand ultra-high working pressures of 150MPa and above, meeting the ultimate pressure requirements for deep coal seam fracturing.

[0016] 2. In this invention, the automatic pressure stabilization function of the intelligent control system can respond in real time to pressure fluctuations caused by the expansion of coal seam fractures. By quickly adjusting the power output, the pumping pressure is stabilized at the set value. The dual composite stabilization of pressure and flow rate is conducive to forming a more uniform and fully expanded fracture network in the coal seam, which significantly improves permeability and gas extraction efficiency.

[0017] 3. In this invention, by arranging vibration and temperature sensors at key locations such as the crankshaft main bearing housing, crosshead slide, and ultra-high pressure cylinder block, the intelligent control system can monitor the mechanical and thermal states of the power and hydraulic ends in real time. Based on the analysis of vibration spectrum and temperature trends, the system can provide early warning of faults before substantial damage to components occurs. Combined with over-limit protection and soft start-stop functions, it transforms reactive post-event maintenance into proactive prediction and protection, greatly improving the safety of system operation and reducing the risk of major failures and maintenance costs. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the working process of the high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system for deep coal seams proposed in this invention. Detailed Implementation

[0019] The technical solutions in 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.

[0020] This invention provides a high-pressure, high-flow-rate, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams, such as... Figure 1 As shown, it includes: The power unit includes a high-strength alloy crankshaft and an integrated cast frame, which are used to convert the rotational power of the prime mover into the reciprocating linear motion power of the plunger. The hydraulic end, connected to the power end, includes a self-reinforcing prestressed winding ultra-high pressure cylinder and an inlet and outlet valve with an adaptive sealing structure. The plunger reciprocates in the ultra-high pressure cylinder to draw in atmospheric pressure water and pump it out as ultra-high pressure water. The plunger is a ceramic-metal composite plunger. High-pressure pipeline systems, connected to the outlet of the hydraulic end, include multi-layer steel wire wound hoses or thick-walled steel pipes and self-balancing high-pressure sealing quick-connect couplings, for conveying ultra-high pressure water flow; The intelligent control system is used to monitor the pressure, flow, vibration and temperature parameters of the power end, hydraulic end and high-pressure pipeline system in real time, and to perform automatic pressure stabilization control based on the pressure parameters, while also performing over-limit protection, fault warning and soft start-stop functions.

[0021] Specifically, the pumping system mainly consists of a power end, a hydraulic end, a high-pressure pipeline system, and an intelligent control system. The output shaft of the power end is mechanically connected to the input end of the hydraulic end. The outlet of the hydraulic end is connected to the inlet of the high-pressure pipeline system via a flange or a self-balancing high-pressure sealed quick-connect fitting in the high-pressure pipeline system. The intelligent control system is connected to various sensors arranged on the power end, hydraulic end, and high-pressure pipeline system via signal cables, and is also connected to the prime mover and actuators in the system via control cables. The core function of the power unit is to convert the rotational power provided by the external prime mover into the power to drive the pistons in the hydraulic end to perform high-speed reciprocating linear motion. To achieve this function and withstand ultra-high alternating loads, the key components of the power unit employ specific designs and materials. Specifically, the power unit includes a high-strength alloy crankshaft and an integrated casting frame. The high-strength alloy crankshaft is preferably forged from 42CrMoA or equivalent high-strength alloy steel and undergoes tempering heat treatment and surface nitriding or high-frequency quenching strengthening processes to give it extremely high resistance to bending and torsional fatigue. The integrated casting frame is made of QT600-3 or equivalent high-strength ductile iron and is formed into a high-rigidity, closed-box structure through a one-time casting process. The internal cavity of this frame is precision-machined to form the main bearing housing for precise installation and support of the high-strength alloy crankshaft, the crosshead slide for guiding the crosshead connected to the crankshaft in linear motion, and the integrated lubrication circuit for providing forced circulation lubrication to the entire power unit. The prime mover, such as a high-power explosion-proof motor or diesel engine, is connected to one end of a high-strength alloy crankshaft via a coupling to drive its rotation. The hydraulic end is directly connected to the power end. Its core function is to continuously pump atmospheric water into ultra-high pressure water using the reciprocating motion of a plunger. The hydraulic end includes a self-reinforcing prestressed wound ultra-high pressure cylinder and at least one set of inlet and outlet valves with adaptive sealing structures. The self-reinforcing prestressed wound ultra-high pressure cylinder is a component that bears the core pump pressure. Its cylinder body is made of high-strength alloy steel and is manufactured by winding multiple layers of high-strength steel wire or carbon fiber composite material on the outer wall of the cylinder with specific prestress, so that it works under pre-applied reverse stress, thereby significantly improving its pressure-bearing capacity and resistance to internal pressure pulsation fatigue. The plunger is made of ceramic-metal composite material, such as a composite of zirconia-toughened alumina ceramic and a metal matrix, giving it high hardness, high wear resistance, and good impact toughness. One end of the plunger is connected to the crosshead of the power end, and the other end extends into the inner cavity of the self-reinforcing prestressed wound ultra-high pressure cylinder. Both the inlet and outlet valves use valve assemblies with adaptive sealing structures. This adaptive sealing structure typically includes a valve core, a valve seat, and one or more elastic compensating elements, such as a butterfly spring assembly. When the operating pressure increases, the elastic compensating elements are further compressed, thereby automatically increasing the sealing specific pressure between the valve core and the valve seat to ensure sealing reliability under high pressure; when the pressure decreases, the sealing specific pressure decreases accordingly, reducing unnecessary friction and wear, thereby extending the seal life. During operation, the prime mover drives a ceramic-metal composite plunger to reciprocate within a self-reinforcing prestressed wound ultra-high pressure cylinder via the power end. When the plunger returns, a negative pressure is created inside the cylinder, and the inlet valve opens under the pressure difference, drawing in atmospheric pressure water. When the plunger advances, the inlet valve closes, the water is compressed, and the pressure rapidly rises to the set value. At this point, the outlet valve opens, and the ultra-high pressure water is discharged. The high-pressure pipeline system, connected to the outlet of the hydraulic end, is used to safely and reliably deliver the generated ultra-high-pressure water flow to the fracturing tools or target coal seam underground. The high-pressure pipeline system mainly includes the main delivery pipeline and connectors. The main delivery pipeline uses multi-layered steel wire wound hydraulic hoses or thick-walled alloy steel pipes. The rated working pressure of these pipelines is no less than 150 MPa to match the output capacity of the hydraulic end. The connectors are preferably self-balancing high-pressure sealing quick-connect fittings. During connection, the internal sealing components of this fitting can undergo radial deformation under axial force, automatically compensating for minor alignment errors between the pipelines. The combination of a metal surface and an elastic sealing ring achieves static and dynamic sealing under high pressure, ensuring no leakage at the connection under high pressure and pulsating conditions. The intelligent control system is the monitoring and control center of the system, ensuring its safe, stable, and efficient operation over extended periods under ultra-high pressure and high flow conditions. It provides comprehensive real-time monitoring and closed-loop control of the power, hydraulic, and high-pressure pipeline systems. Specifically, it monitors physical parameters including system output and key node pressures, the flow rate of the transported water medium, vibration signals from key mechanical components in the power and hydraulic ends, and temperatures at critical locations such as bearings and cylinders. Based on real-time pressure data, the intelligent control system uses built-in controllers and algorithms to automatically stabilize pressure. When pressure deviates from the set value, the controller responds quickly by adjusting the prime mover's speed or pump displacement to stabilize the system output pressure within the target range. Simultaneously, the system continuously performs over-limit protection; if any monitored parameter exceeds a preset safety threshold, the system immediately issues an alarm and performs protective actions such as load reduction or shutdown. The system also has a fault warning function; through spectral analysis of vibration signals and judgment of temperature change trends, it can issue maintenance warnings before substantial damage occurs to components such as bearing wear or plunger scoring. In addition, the system executes a soft start-stop procedure during startup and shutdown to achieve a smooth pressure build-up and release, avoiding water hammer impact on pipelines and pumps.

[0022] Furthermore, the power end is a five-cylinder plunger pump power end, and the high-strength alloy crankshaft has cranks corresponding to the five plungers, and is made through heat treatment and surface strengthening processes to withstand ultra-high alternating loads. The integrated casting frame is a one-piece molded high-rigidity box structure, which integrates the main bearing housing for mounting the high-strength alloy crankshaft, the crosshead slide for guiding the piston movement, and the oil circuit of the forced circulation lubrication system.

[0023] Specifically, the high-strength alloy crankshaft has five cranks, each with a phase difference of 72 degrees. This crankshaft design corresponds one-to-one with five ceramic-metal composite plungers, and the rotational motion is converted into a reciprocating linear motion of the five plungers with staggered phases via connecting rods. After forging and finishing, the high-strength alloy crankshaft undergoes tempering heat treatment to achieve excellent overall mechanical properties. Subsequently, surface strengthening processes are applied to the journals and crank surfaces, including but not limited to high-frequency induction hardening or ion nitriding, to significantly improve surface hardness, wear resistance, and fatigue strength, thereby ensuring its ability to withstand the ultra-high alternating loads generated by the reciprocating motion of five cylinders over long periods. The integrated casting frame is specifically a high-rigidity box structure formed in one casting. The frame is made of high-strength ductile iron, and a blank containing all necessary structural features is obtained through precision casting, followed by integrated machining on a CNC machine tool to ensure the accuracy and relative position of each mounting surface. Inside this integrated casting frame, several key functional structures are integrated: including multiple main bearing seats for precise mounting and support of the high-strength alloy crankshaft, the main bearing seats being precision-machined hole systems; five crosshead slides for guiding the linear motion of the crossheads connected to each crankshaft, the slides being precision-ground guide planes or curved surfaces; and an integrated lubrication circuit providing forced pressure lubrication for all moving parts within the power end, the circuit including main oil passages, branch oil passages, and lubrication holes leading to each main bearing seat and crosshead slide. The output shaft of the prime mover is connected to one end of a high-strength alloy crankshaft via a heavy-duty coupling. When the prime mover operates, it drives the high-strength alloy crankshaft to rotate. The crankshaft, through five sets of connecting rods, drives five crossheads to reciprocate within their corresponding crosshead slides, thereby driving five ceramic-metal composite plungers connected to the crossheads, forming a reciprocating motion sequence with a phase difference of 72 degrees. This five-cylinder staggered structure allows the water intake and drainage processes at the hydraulic end to overlap and connect in time, thus merging the pulsed flow of individual plungers into a more stable and continuous ultra-high-pressure water flow with significantly reduced flow fluctuations. This is crucial for the stable fracturing of deep coal seams. Simultaneously, the one-piece molded high-rigidity housing structure provides extremely stable support for the entire power conversion process, effectively suppressing vibration and deformation, and forming the structural foundation for the system to withstand ultra-high loads and achieve long-term operation.

[0024] Furthermore, the power unit also includes an optimized bearing system and a forced circulation lubrication system that are matched with the integrated casting frame.

[0025] Specifically, the optimized bearing system mainly includes the main bearings installed in the main bearing housing of the integrated casting frame, and the connecting rod large and small end bearings connecting the crankshaft and the crosshead. The main bearings use high-precision, high-load-capacity double-row self-aligning roller bearings or sliding bearings, whose dimensions are precisely matched with the bore diameter of the main bearing housing. The connecting rod large and small end bearings use wear-resistant bushings or needle roller bearings. The selection and arrangement of these bearings have been specially optimized to provide stable support for the rotational motion of the high-strength alloy crankshaft and the reciprocating motion of the crosshead within a limited installation space, and to maximize the dispersion and bearing of the huge alternating forces transmitted from each kinematic pair. The forced circulation lubrication system is an independent pressurized oil circulation device. This system includes a lubricating oil tank, oil pump, oil filter, oil cooler, and an integrated lubrication circuit throughout the integrated casting frame. The oil pump draws oil from the lubricating oil tank, pressurizes it, filters it through the oil filter, and then distributes it to various branch circuits via the main oil passage of the integrated lubrication circuit. The pressurized lubricating oil is forced to the lubrication points of each main bearing, each connecting rod large and small end bearing, and each crosshead slide surface, forming a complete lubricating oil film to achieve friction reduction, cooling, and cleaning. After lubrication, the lubricating oil flows out from the bearing gaps, converges at the bottom of the frame, and returns to the lubricating oil tank after being cooled by the oil cooler, forming a complete closed-loop cycle. The continuous operation of the forced circulation lubrication system ensures that all critical moving parts on the power end remain in good lubrication condition even under long-term high-load operation. This is crucial for preventing abnormal wear, galling failure, and controlling bearing temperature, supporting the long-term operation of the system.

[0026] Furthermore, in the hydraulic end, the self-reinforcing prestressed wound ultra-high pressure cylinder is formed by pre-applying reverse stress during manufacturing.

[0027] Specifically, the high pressure-bearing capacity and long fatigue life of the self-reinforcing prestressed wound ultra-high pressure cylinder in the hydraulic end stem from its unique manufacturing method. This method involves pre-applying a reverse stress opposite to the working internal pressure during manufacturing. The specific manufacturing process is as follows: First, a cylinder core is forged or machined from high-strength alloy steel. This core serves as the main structure bearing the internal pressure. Then, a first layer of high-strength steel wire or strip is wound around the outer cylindrical surface of the cylinder core with extremely high initial tension. The clamping force generated by the initial tension produces a radial compressive stress within the wall thickness of the cylinder core; this is the pre-applied reverse stress. After the first layer is wound, a second, third, and subsequent layers are wound with a specific tension. Each layer further increases the pre-tension force on the core. The number of winding layers, the winding tension of each layer, and the material strength must be precisely designed and calculated so that after the winding process, the inner wall of the core already possesses a considerable residual compressive stress under zero internal pressure. When the cylinder is under internal water pressure during operation, the tensile stress generated by the working internal pressure must first offset the residual compressive stress pre-added during manufacturing before a net tensile stress is generated within the cylinder material. Therefore, compared to a traditional single-layer cylinder of the same size and material, this self-reinforcing prestressed winding structure significantly reduces the actual amplitude of cyclic stress borne by the cylinder. This reduction in stress level directly translates into an order-of-magnitude improvement in the cylinder's resistance to pulsating pressure fatigue, enabling it to withstand long-term, high-frequency pressure alternation, thus ensuring the long-term continuous and stable operation of the pumping system.

[0028] Furthermore, the inlet and outlet valves with an adaptive sealing structure are configured to automatically adjust the sealing pressure ratio according to the working pressure.

[0029] Specifically, both the inlet and outlet valves in the hydraulic end employ valve assemblies with an adaptive sealing structure. The core function of this adaptive sealing structure is to automatically and continuously adjust the sealing pressure applied to the sealing surfaces of the valve core and seat based on the actual working pressure at the valve port. A typical implementation is as follows: The valve core and seat constitute the main sealing pair. One or more sets of elastic compensation elements are provided on the back of the valve core or below the valve seat. These elastic compensation elements are typically butterfly spring sets or cylindrical helical springs with a specific stiffness coefficient. In the initial installation state of the valve, the elastic compensation elements are pre-compressed to a certain stroke, thereby providing an initial pre-tight sealing force to ensure sealing under low pressure. When the system operating pressure increases, the medium pressure acting on the valve core also increases. This increased medium pressure pushes the valve core, causing it to further compress the elastic compensating element. This further compression of the elastic compensating element results in a proportional increase in the reaction force exerted on the valve core and valve seat sealing pair—the actual sealing force. The sealing specific pressure is equal to the sealing force divided by the sealing contact area. Therefore, an increase in operating pressure leads to an automatic increase in sealing force, thereby achieving automatic adjustment of the sealing specific pressure. This process ensures that the valve maintains a reliable seal under high-pressure conditions, preventing high-pressure leakage. Conversely, when the working pressure decreases, the medium pressure acting on the valve core decreases, and the elastic compensation element pushes the valve core back under its own elastic force, resulting in a corresponding decrease in sealing force and sealing specific pressure. This avoids unnecessary frictional wear or plastic deformation of the sealing pair due to excessive specific pressure under low pressure or closed conditions, significantly extending the service life of the valve core and valve seat. Through this pressure-adaptive design, the inlet and outlet valve can maintain a suitable sealing specific pressure that matches the current pressure throughout the entire pressure operating range, thereby ensuring sealing reliability while minimizing wear and achieving long service life of the hydraulic end.

[0030] Furthermore, the self-balancing high-pressure sealing quick-connect coupling is configured to automatically compensate for alignment errors and achieve a metal seal during connection.

[0031] Specifically, the self-balancing high-pressure sealing quick-connect coupling in high-pressure pipeline systems is designed for rapid and reliable connection under ultra-high pressure conditions. Its function is to automatically compensate for minor axial and radial alignment errors between two pipelines during the connection process, and to form a reliable metal seal after final tightening. This coupling typically consists of a male and a female connector. At the front end of the male connector, there is a metal sealing element with a specific conical or spherical surface, usually made of high-hardness alloy steel. Inside the female connector, there is a corresponding conical or spherical metal sealing seat. Inside the coupling, there is also a self-balancing compensation mechanism consisting of a snap ring, a sliding sleeve, and an elastomer. During the connection process, the male connector is inserted into the female connector. Even if there are minor misalignments in the axes or end faces of the two pipes during insertion, the conical or spherical fit between the metal seal at the front of the male connector and the sealing seat of the female connector guides them towards gradual alignment. Simultaneously, the self-balancing compensation mechanism inside the connector activates, and the internal elastic element deforms to absorb and accommodate the offset force caused by the alignment error. This allows the seal of the male connector to smoothly and without jamming against the sealing seat of the female connector; this process is known as automatic compensation for alignment errors. When the connector is fully inserted and the external locking sleeve is rotated or pushed to the locked position, the locking mechanism generates a strong axial locking force. This axial force forces a slight elastic or plastic deformation between the metal seal of the male connector and the metal sealing seat of the female connector, causing their metal sealing surfaces to fit tightly together around the entire circumference, forming a high-pressure, sealed metal-to-metal contact sealing ring. This seal formed by direct metal-to-metal contact can withstand static pressures exceeding 150 MPa and dynamic pressure shocks generated by pump pulsations, providing extremely reliable sealing performance. For disassembly, simply reverse the locking mechanism; the self-balancing compensation mechanism will reset, allowing for easy separation of the connector. This design ensures convenient, repeatable, and highly safe high-pressure pipeline connections.

[0032] Furthermore, the intelligent control system includes: Pressure sensors and flow sensors are used to collect pressure and flow parameters in real time; Vibration and temperature sensors are respectively arranged at the main bearing housing of the high-strength alloy crankshaft in the power end, at the crosshead slide of the integrated casting frame, and at the outer wall of the self-reinforcing prestressed winding ultra-high pressure cylinder in the hydraulic end, for real-time acquisition of vibration and temperature parameters. The controller is used to perform automatic voltage regulation control, over-limit protection, fault warning and soft start / stop functions.

[0033] Specifically, the intelligent control system, as the monitoring and control center of the entire pumping system, consists of a sensor network and a controller. The sensor network is divided into two categories. The first category is process parameter sensors, including pressure sensors and flow sensors. Pressure sensors are installed on the outlet pipeline at the hydraulic end and on key nodes of the high-pressure pipeline system to collect the system's working pressure parameters in real time. Flow sensors are installed on the outlet pipeline at the hydraulic end to collect the output water flow parameters in real time. The second category consists of equipment status sensors, including vibration and temperature sensors. These sensors are not randomly placed but are strategically installed at the most critical mechanical components of the power and hydraulic ends, based on mechanical force and thermal load analysis. Specifically, on the power end, at least one vibration sensor and one temperature sensor are installed at the main bearing housing of the high-strength alloy crankshaft to monitor the crankshaft's rotational vibration and the bearing's operating temperature. At least one vibration sensor is installed at the crosshead slide of the integrated casting frame to monitor the vibration of the crosshead's reciprocating motion. On the hydraulic end, at least one temperature sensor is installed on the outer wall of the self-reinforced prestressed wound ultra-high pressure cylinder to monitor the cylinder's operating temperature under high pressure. These locations are the most direct and sensitive indicators of the health of the core moving parts on both the power and hydraulic ends. The controller is the core processing unit of the intelligent control system, typically employing an industrial programmable logic controller (PLC) or an industrial computer. Pressure sensors, flow sensors, vibration sensors, and temperature sensors are all connected to the controller's analog or digital input modules via signal cables, transmitting real-time collected pressure, flow, vibration, and temperature parameters to the controller. The controller's output modules are connected to the speed control device of the prime mover, system alarms, and actuator valves via control cables. The controller internally stores and runs pre-programmed control programs. These programs enable the controller to perform automatic pressure stabilization control based on real-time pressure parameters, implement over-limit protection based on all monitored parameters, provide fault warnings based on the changing trends of vibration and temperature parameters, and perform soft start / stop functions during system startup and shutdown. Through the collaborative work of the sensor network and the controller, the intelligent control system achieves comprehensive perception and intelligent decision-making regarding the operating conditions of the pumping system.

[0034] Furthermore, automatic voltage regulation control is achieved by adjusting the speed of the prime mover or the displacement of the pump through the controller.

[0035] Specifically, the automatic pressure stabilization function of the intelligent control system works by adjusting the system's power output in real time through the controller to maintain the outlet pressure at a set value. This adjustment is achieved through two equivalent methods: adjusting the speed of the prime mover or adjusting the effective displacement of the pump. A typical implementation process is as follows: the operator sets the target pressure value on the controller's interface. During system operation, a pressure sensor installed on the outlet pipeline continuously measures the actual pressure value and transmits this pressure parameter to the controller in real time. The controller's internal program compares the received actual pressure value with the preset target pressure value, calculating the pressure deviation and the rate of change of deviation. Based on this deviation and the rate of change, the controller calculates a regulating output signal in real time according to a preset proportional-integral-derivative control algorithm. This regulating output signal is sent to the corresponding actuator. When adjusting the prime mover speed, the output signal is sent to the prime mover's frequency converter or electronic speed controller, driving the prime mover's speed to increase or decrease. The change in speed directly alters the rotational speed of the high-strength alloy crankshaft at the power end, thereby changing the reciprocating frequency of the ceramic-metal composite plunger at the hydraulic end, ultimately achieving regulation of the system's output flow and pressure. When adjusting the pump displacement, the output signal is sent to a hydraulic or electric displacement regulating mechanism installed at the hydraulic end. This mechanism directly changes the effective stroke of the plunger, thereby achieving stepless adjustment of displacement and pressure. Through the closed-loop control process described above, when the actual pressure is lower than the set value, the controller issues a command to increase the rotational speed or displacement, causing the system output pressure to rise; when the actual pressure is higher than the set value, the controller issues a command to decrease the rotational speed or displacement, causing the system output pressure to fall. This cyclical feedback and adjustment can quickly and smoothly offset pressure fluctuations caused by the opening and expansion of coal seam fractures or other factors, dynamically stabilizing the system output pressure near the target value, thereby ensuring the stability and effectiveness of the hydraulic fracturing process.

[0036] Furthermore, fault warning is based on the analysis of vibration spectrum or temperature change trends, providing early warning before substantial damage to components occurs.

[0037] Specifically, the fault early warning function of the intelligent control system aims to achieve predictive maintenance. Its core technology is based on in-depth analysis of equipment status data, particularly the analysis of vibration spectrum or temperature change trends, thereby issuing early warning signals before substantial damage to components. The specific implementation process is as follows: During normal system operation, the controller continuously receives and records vibration and temperature parameters from vibration and temperature sensors. This data forms the historical baseline of the status of each component. For vibration early warning, the controller's built-in algorithm performs real-time spectrum analysis on the acquired vibration signals. This analysis converts the time-domain vibration waveform to the frequency domain, obtaining the distribution of vibration energy at different frequencies, i.e., the vibration spectrum. The controller compares the current real-time vibration spectrum with the reference spectrum stored under normal operating conditions. When the analysis detects a sustained abnormal increase in the amplitude of a specific frequency component, especially a frequency component related to the rotational frequency of the high-strength alloy crankshaft, the reciprocating frequency of the piston, or its harmonics, or when a new abnormal frequency component appears, it indicates that the corresponding mechanical component, such as a bearing, gear, or crosshead, may have experienced potential faults such as early wear, increased clearance, or misalignment. The controller then generates and issues an early vibration warning. For temperature warnings, the controller continuously monitors and records temperature parameters at the main bearing housing, crosshead slide, and outer wall of the ultra-high pressure cylinder. The controller analyzes the long-term trends of these temperature values ​​and the temperature difference between adjacent measuring points. When the temperature at a measuring point shows an abnormal upward trend inconsistent with load changes, or when the temperature difference between two related measuring points exceeds the normal range, it indicates that there may be problems such as poor lubrication, increased friction, or cooling failure in that area. The controller then generates and issues an early temperature warning. The warning signal is transmitted to the operating interface through the controller's output module, alerting the operator in the form of sound and light. This warning precedes the over-limit protection shutdown triggered by complete component failure, providing maintenance personnel with ample time for planned maintenance response, thereby avoiding unplanned downtime and significantly improving the system's operational reliability and availability.

[0038] Furthermore, the rated pressure resistance of multi-layer steel wire spiral hoses or thick-walled steel pipes shall not be less than 150 MPa.

[0039] Specifically, the high-pressure pipeline system serves as the channel for transmitting ultra-high-pressure water flow, and its own pressure-bearing capacity must match the maximum output pressure of the pumping system. Therefore, the multi-layered steel wire spiral hoses or thick-walled steel pipes constituting the main pipeline of this system are all rated with a pressure resistance of no less than 150 MPa. For multi-layered steel wire spiral hoses, their structure typically includes an inner rubber layer, multiple layers of high-strength steel wire braided or wound reinforcement, and an outer rubber layer. The reinforcement layer is crucial for pressure resistance, using high-breaking-tensile-strength steel wire tightly wound at a specific winding angle and number of layers, with the winding directions between layers usually alternating. This multi-layered, staggered winding structure allows the hose to withstand extremely high internal pressure and pressure pulsations simultaneously. The selected hose model, with its rated working pressure and verification pressure specified by the manufacturer, meets the requirement of no less than 150 MPa. For thick-walled steel pipes, high-strength alloy seamless steel pipes are used, such as alloy steel pipes with grades 35CrMo or 42CrMo. Thick-walled refers to the pipe's wall thickness being rigorously calculated to ensure that, under an internal pressure of 150 MPa, the stress on the pipe wall remains within a safe range below the material's yield strength, with sufficient safety margin to cope with pressure peaks and fatigue. Pipe connections typically use unions or flanges, equipped with metal gaskets of equivalent pressure rating. A rated pressure resistance of not less than 150 MPa is a fundamental condition for ensuring the safe and stable operation of the entire pumping system under designed high-pressure conditions. It guarantees that the entire delivery path from the hydraulic end outlet to the downhole fracturing tools has sufficient strength reserve to safely accommodate ultra-high-pressure water flow, preventing serious accidents such as pipe rupture.

[0040] Finally, it should be noted that the above description 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-pressure, high-flow-rate, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams, characterized in that: include: The power unit includes a high-strength alloy crankshaft and an integrated cast frame, which are used to convert the rotational power of the prime mover into the reciprocating linear motion power of the plunger. The hydraulic end, connected to the power end, includes a self-reinforcing prestressed winding ultra-high pressure cylinder and an inlet and outlet valve with an adaptive sealing structure. The plunger reciprocates within the ultra-high pressure cylinder to draw in atmospheric pressure water and pump it out as ultra-high pressure water. The plunger is a ceramic-metal composite plunger. A high-pressure pipeline system, connected to the outlet of the hydraulic end, includes a multi-layer steel wire wound hose or a thick-walled steel pipe and a self-balancing high-pressure sealing quick-connect coupling, for conveying the ultra-high pressure water flow; The intelligent control system is used to monitor the pressure, flow, vibration and temperature parameters of the power end, hydraulic end and high-pressure pipeline system in real time, and to perform automatic pressure stabilization control based on the pressure parameters, while also performing over-limit protection, fault warning and soft start-stop functions.

2. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams according to claim 1, characterized in that, The power end is a five-cylinder plunger pump power end, and the high-strength alloy crankshaft has cranks corresponding to the five plungers, and is made by heat treatment and surface strengthening processes to withstand ultra-high alternating loads. The integrated casting frame is a one-piece molded high-rigidity box structure, which integrates a main bearing housing for mounting the high-strength alloy crankshaft, a crosshead slide for guiding the piston movement, and an oil circuit for a forced circulation lubrication system.

3. The high-pressure, high-flow-rate, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams according to claim 2, characterized in that, The power unit also includes an optimized bearing system and a forced circulation lubrication system that are matched with the integrated casting frame.

4. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams according to claim 1, characterized in that, In the hydraulic end, the self-reinforcing prestressed winding ultra-high pressure cylinder body is formed by pre-applying reverse stress during manufacturing.

5. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams according to claim 1, characterized in that, The inlet and outlet valve with an adaptive sealing structure is configured to automatically adjust the sealing pressure ratio according to the working pressure.

6. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams according to claim 1, characterized in that, The self-balancing high-pressure sealing quick connector is configured to automatically compensate for alignment errors and achieve metal sealing during connection.

7. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system suitable for deep coal seams according to claim 1, characterized in that, The intelligent control system includes: Pressure sensors and flow sensors are used to collect the pressure parameters and flow parameters in real time; Vibration sensors and temperature sensors are respectively arranged at the main bearing seat of the high-strength alloy crankshaft in the power end, at the crosshead slide of the integrated casting frame, and at the outer wall of the self-reinforcing prestressed winding ultra-high pressure cylinder in the hydraulic end, for real-time acquisition of vibration parameters and temperature parameters. The controller is used to perform the automatic voltage regulation control, over-limit protection, fault warning and soft start-stop functions.

8. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system for deep coal seams according to claim 7, characterized in that, The automatic voltage regulation control is achieved by adjusting the speed of the prime mover or the displacement of the pump through the controller.

9. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system for deep coal seams according to claim 7, characterized in that, The fault warning is based on the analysis of vibration spectrum or temperature change trends, and provides early warning before substantial damage to the component occurs.

10. The high-pressure, high-flow, long-lasting hydraulic permeability enhancement pumping system for deep coal seams according to claim 1, characterized in that, The rated pressure resistance of the multi-layer steel wire wound hose or thick-walled steel pipe shall not be less than 150 MPa.

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