Leakage-free reciprocating pump device for conveying light hydrocarbon medium

Abstract

The invention discloses a leak-free reciprocating pump device for conveying a light hydrocarbon medium, which comprises a pump body, a box body and a plunger, and a plunger operation cavity, a liquid inlet valve and a liquid discharge valve are arranged in the pump body. And a stepped depressurization recovery module and an active hydraulic blocking and sealing module are sequentially arranged in the box body. The stepped depressurization recovery module achieves step-by-step depressurization of leaked media through two stages of sealing assemblies and a leakage collection cavity between the two stages of sealing assemblies, and the media are guided back through a backflow one-way valve. The active hydraulic blocking and sealing module injects lubricating oil higher than medium pressure into the lubricating oil cavity to form hydraulic sealing, and the active hydraulic blocking and sealing module and the rear end sealing assembly jointly block medium migration. And the lubricating oil cavity is connected with an external oil station to form a circulating cooling loop. The two modules cooperate to form a two-way blocking closed-loop sealing system, and the problems of leakage and gasification in light hydrocarbon medium high-pressure conveying are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of leakage-proof media conveying technology, and in particular to a leakage-free reciprocating pump device for conveying light hydrocarbon media. Background Technology

[0002] Light hydrocarbons are the main components of petroleum and natural gas. They are low-molecular-weight hydrocarbons, generally referring to C2-C4 hydrocarbons and their mixtures (liquid hydrocarbons). They are gaseous at room temperature and liquefy when pressurized and heated to a certain temperature. Centrifugal pumps are commonly used for transporting light hydrocarbons. However, leaks into the atmosphere during transport pose various health hazards. While centrifugal pumps use a flushing method to prevent leaks, this is often ineffective. Centrifugal pumps are insufficient for high-pressure outputs ≥15MPa. In oilfield production, the huff-and-puff process involves filtering and separating associated gas using a compressor, then pressurizing and injecting it into the well to improve oil recovery. However, this process is expensive and can only be tested, not widely adopted. A technology using reciprocating pumps to directly inject light hydrocarbons into the well to achieve miscible flooding can further improve oil recovery. Light hydrocarbons have a high miscibility with formation crude oil, forming a single fluid that significantly reduces interfacial tension, allowing for 100% recovery. Crude oil, buried deep within the tiny pores of underground rock, exhibits "viscous" and "adhesive" properties. Conventional water flooding often leaves behind significant oil films and droplets, making it essential to utilize light hydrocarbon miscible flooding to enhance oil recovery. However, conventional pumps are insufficient for leak-proofing light hydrocarbon transport. Reciprocating pumps, due to the dynamic and static reciprocating motion of the plunger and sealing packing, struggle to achieve zero-leakage light hydrocarbon transport within their lifespan under high pressure (≥20 MPa). Therefore, given the widespread user demand for improved oil recovery through light hydrocarbon input and the resolution of leakage issues during light hydrocarbon transport, developing a leak-free reciprocating pump for transporting light hydrocarbons is crucial. Summary of the Invention

[0003] To address the aforementioned shortcomings, this invention proposes a leak-free reciprocating pump device for conveying light hydrocarbon media. Through the synergistic effect of a stepped pressure reduction and recovery module and an active hydraulic sealing module, a bidirectional closed-loop sealing system is constructed to achieve active media recovery and dynamic pressure sealing, effectively solving the leakage and vaporization problems in the high-pressure conveying process of light hydrocarbon media.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a leak-free reciprocating pump device for conveying light hydrocarbon media, comprising a pump body, a plenum disposed on the pump body, and a plunger passing through the plenum and reciprocating, wherein the pump body is provided with a plunger running chamber communicating with the front end of the plunger, as well as an inlet valve and a drain valve. The following are arranged sequentially along the axial direction within the function body: The stepped pressure reduction and recovery module includes a first sealing assembly, a leakage collection chamber, and a second sealing assembly arranged sequentially along the direction of medium leakage. The first and second sealing assemblies create flow resistance through the tight fit between themselves and the plunger, thereby generating a strong throttling effect on the light hydrocarbon medium leaking along the plunger. This allows the first sealing assembly to achieve initial flow obstruction and initial pressure reduction, while the second sealing assembly achieves final interception and sealing of the residual medium after the leakage collection chamber is depressurized. The leakage collection chamber is connected to a medium return check valve through a channel opened on the body to collect the light hydrocarbon medium after the first pressure reduction, and to guide the medium back through the check valve when the pressure in the chamber exceeds a preset value. The active hydraulic barrier module includes a lubricating oil chamber and a third sealing assembly located at the rear end of the stepped pressure reduction and recovery module. The lubricating oil chamber is connected to an external oil station through a lubricating oil inlet and a lubricating oil outlet on the gland, forming a circulating cooling circuit for the lubricating oil. The oil station injects system lubricating oil into the lubricating oil chamber at a pressure higher than that of the light hydrocarbon medium at the pump inlet, thereby forming a dynamic hydraulic barrier pointing towards the stepped pressure reduction and recovery module. The third sealing assembly is located at the rear end of the lubricating oil chamber and is used to seal the lubricating oil in the system to maintain the stability of the dynamic hydraulic barrier and serve as the final sealing interface of the closed-loop sealing system facing the atmosphere. The stepped pressure reduction and recovery module and the active hydraulic barrier module work together to form a closed-loop sealing system with bidirectional barrier.

[0005] Compared with the prior art, the advantages of the present invention are as follows: This device, through the coordinated operation of a stepped depressurization and recovery module and an active hydraulic barrier module, constructs a complete bidirectional barrier-sealing system, effectively solving the problem of easy leakage of light hydrocarbon media during high-pressure transportation. The stepped depressurization and recovery module forms a multi-stage sealing and flow-blocking system through its internally arranged first sealing component, leakage collection chamber, and second sealing component. This allows the light hydrocarbon media leaking along the plunger to undergo initial flow blocking and initial depressurization before entering the leakage collection chamber. When the pressure inside the chamber exceeds a preset value, the media is safely guided back through a one-way return valve. The second sealing component is specifically responsible for the final interception and sealing of residual trace media after depressurization from the leakage collection chamber, ensuring that the media, after initial depressurization and recovery, will not continue to migrate downstream. Simultaneously, the active hydraulic barrier module injects system lubricating oil into the lubrication chamber at a pressure higher than the media pressure, forming a stable dynamic hydraulic barrier that effectively prevents the media from migrating downstream. The third sealing component, located at the rear end of the lubrication chamber, ensures the maintenance of the lubricating oil seal and serves as the final sealing interface facing the atmosphere. The two modules work together to form a bidirectional sealing force. The final interception function of the second sealing component is closely integrated with the dynamic barrier function of the active hydraulic barrier module, together forming a full-path sealing guarantee from the medium side to the atmosphere side. This completely eliminates the risk of leakage of light hydrocarbon media. At the same time, the temperature of the sealing area is effectively controlled by the circulating cooling of the system lubricating oil, which significantly improves the service life of the plunger and sealing components. This ensures the long-term operational reliability, environmental safety and operational economy of the unit when transporting high-pressure volatile light hydrocarbon media.

[0006] As an improvement, the medium return check valve is connected to the inlet manifold of the light hydrocarbon medium storage tank via a pipeline, forming a recovery path for the leaked medium. By safely guiding the leaked light hydrocarbon medium back to the inlet manifold inside the system, closed-loop management of the leaked medium is achieved. This not only completely eliminates the escape of harmful media into the external environment and ensures operational safety and environmental compliance, but more importantly, it reintroduces the leaked medium as an effective working fluid into the transportation process, avoiding any waste of materials. At the same time, the direct connection between this return path and the inlet manifold cleverly utilizes the relatively stable pressure environment on the storage tank side, establishing a reliable pressure relief benchmark for the leak chamber and ensuring that the stepped pressure reduction and recovery module can work continuously and stably.

[0007] As an improvement, the oil station includes an oil pump whose outlet pressure is configured to be higher than the pressure of the light hydrocarbon medium at the pump inlet. This creates a positive pressure barrier at the lubricating oil chamber, pointing towards the stepped pressure reduction and recovery module. This ensures that the oil pressure within the lubricating oil chamber is always higher than the pressure of the medium ahead, thus forming a stable and reliable dynamic hydraulic sealing barrier. This barrier effectively prevents the light hydrocarbon medium from penetrating backward, fundamentally cutting off the leakage path. Simultaneously, the continuously circulating lubricating oil not only provides a sealing function but also carries away the heat generated in the sealing friction area, preventing excessively high local temperatures that could cause the light hydrocarbon medium to vaporize or the sealing material to fail.

[0008] As an improvement, the circulating cooling circuit also includes a cooling module for dissipating heat from the returning lubricating oil. The cooling module is located downstream of the lubricating oil discharge joint and upstream of the lubricating oil chamber. Through its placement at a key node of the circulating circuit, the cooling module enables timely cooling of the returning lubricating oil. The cooled lubricating oil maintains stable viscosity and sealing performance. When it is reinjected into the lubricating oil chamber, it can continue to perform hydraulic sealing function efficiently. This effectively removes the heat generated by the sealing friction pair, preventing the lubricating oil temperature from continuously rising and causing a decrease in viscosity or deterioration. This ensures that the active hydraulic sealing module can maintain the required working pressure stably for a long time.

[0009] As an improvement, the first, second, and third sealing assemblies all contain multiple axially stacked sealing packings, with flow-blocking rings between adjacent packings to enhance packing rigidity and ensure more uniform compression. The series arrangement of multiple packings distributes the total sealing load across each packing ring, creating a gentler pressure drop gradient through progressively dissipating medium pressure, significantly improving the reliability and durability of the seal. The flow-blocking rings provide a stable support base for each packing ring, effectively enhancing the overall rigidity of the sealing pair and preventing uneven compression or extrusion deformation of the packing under high pressure, ensuring that the axial clamping force is evenly distributed across each packing ring. This uniform stress state allows for the formation of a continuous and stable sealing band between the packing and the plunger, maximizing the contact quality of the sealing interface and effectively preventing premature wear caused by localized stress concentration. Each sealing stage, constructed collaboratively by the packing rings and flow-blocking rings, independently bears a portion of the pressure load, ultimately achieving efficient sealing while significantly extending the service life of the entire sealing system, ensuring the stability and reliability of the device during long-term operation.

[0010] As an improvement, an elastic wear compensation component is also provided on the medium inflow side of the stepped pressure reduction and recovery module within the plenum. This component applies an axial preload to the sealing components in both the stepped pressure reduction and recovery module and the active hydraulic sealing module. This preload simultaneously balances the radial component of the force generated by the high-pressure light hydrocarbon medium, which causes the sealing components to skew. This ensures that the sealing components remain aligned and in sealing contact during the reciprocating motion of the plunger. By continuously applying a stable axial preload, not only is automatic compensation for sealing component wear achieved, but the reaction torque generated by this preload further effectively balances the wear caused by the high-pressure light hydrocarbon medium. The radial force generated by hydrocarbon media penetration, which may cause the sealing assembly to misalign, ensures that each section of the sealing assembly remains precisely aligned under high-speed reciprocating motion of the plunger and high-pressure conditions. This avoids uneven wear of the sealing surface, local overheating, or seal failure caused by uneven force. Its dual function ensures that the sealing pair maintains uniform and stable contact pressure throughout its entire lifespan. It eliminates axial clearance caused by wear and suppresses radial instability, thereby significantly improving the operational reliability and service life of the entire sealing system under high-pressure and variable-load conditions. This provides a fundamental guarantee for achieving the goal of long-term stable zero leakage.

[0011] As an improvement, a micro-gap structure with an axial distance of 2-5 mm between the end face of the plunger operating chamber and the mounting planes of the inlet and outlet valves is incorporated to minimize the residual clearance volume within the chamber. This suppresses the vaporization of light hydrocarbon media caused by drastic pressure changes during the plunger's reciprocating motion and ensures the reciprocating pump maintains high volumetric efficiency. This micro-gap structure compresses the space between the plunger operating chamber and the valve assembly mounting plane to a limit, making it difficult for light hydrocarbon media to form a significantly stagnation zone within the chamber under high-pressure conditions. When the plunger completes its discharge stroke, this micro-gap... Only a trace amount of medium can remain inside, thus effectively avoiding vaporization caused by the rapid expansion of high-pressure medium during subsequent suction strokes. This ensures that the pump chamber always maintains a fluid environment conducive to the medium remaining in a liquid or dense phase, significantly reducing energy loss and hydraulic impact caused by medium phase change. At the same time, the minimized clearance volume allows the plunger to achieve almost complete discharge of the medium in each working cycle, which not only significantly improves the pump's volumetric efficiency but also creates efficient and reliable working conditions for the entire delivery system by maintaining stable fluid continuity.

[0012] As an improvement, the pump body features a multi-cylinder structure. A stepped pressure reduction and recovery module and an active hydraulic sealing module are integrated into the housing of each cylinder in a one-to-one correspondence, forming multiple parallel closed-loop sealing systems. This multi-cylinder parallel sealing structure ensures that each working cylinder is equipped with an independent and complete bidirectional sealing system. Each sealing module operates independently within its respective cylinder without interfering with others. This modular layout ensures that even if a single sealing module requires maintenance or malfunctions, it will not affect the normal operation of other cylinders, greatly improving the reliability and availability of the entire machine. Simultaneously, the multiple sealing systems work collaboratively to jointly undertake the high-pressure sealing task of the entire machine. This allows the reciprocating pump to maintain high output flow while each cylinder achieves the same zero-leakage sealing effect as a single-cylinder structure, realizing a simultaneous large-scale improvement in equipment processing capacity and sealing reliability. This provides a fundamental guarantee for the safe transportation of light hydrocarbon media in large-scale industrial plants. Attached Figure Description

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is an enlarged schematic diagram of a leak-free reciprocating pump device for conveying light hydrocarbon media. Figure 2 A schematic diagram of the connection between a leak-free reciprocating pump device for conveying light hydrocarbon media and external equipment.

[0014] The markings in the above diagrams are as follows: 1. Pump body; 1.1. Plunger running chamber; 2. Gland; 3. Plunger; 4. Inlet valve; 5. Drain valve; 6. Stepped pressure reduction and recovery module; 6.1. First sealing assembly; 6.2. Leakage collection chamber; 6.3. Second sealing assembly; 7. Medium return check valve; 8. Active hydraulic sealing module; 8.1. Lubricating oil chamber; 8.2. Third sealing assembly; 9. Lubricating oil suction connector; 10. Lubricating oil discharge connector; 11. Oil station; 11.1. Oil pump; 11.2. Oil sump; 11.3. Cooling module; 12. Light hydrocarbon medium storage tank; 13. Elastic wear compensation component; 14. Axial guide and support module; 14.1. Front guide section; 14.2. Rear guide section; 15. Compression nut; 16. Front flange. Detailed Implementation

[0015] In this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "planar direction", "circumferential", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0016] like Figures 1 to 2 As shown, a leak-free reciprocating pump device for conveying light hydrocarbon media includes a pump body 1, a casing 2 mounted on the pump body 1, and a plunger 3 that passes through the casing 2 and reciprocates. The pump body 1 contains a plunger operating chamber 1.1 communicating with the front end of the plunger 3, as well as an inlet valve 4 and a drain valve 5. The casing 2 contains a stepped pressure reduction and recovery module 6 and an active hydraulic sealing module 8 arranged sequentially along the axial direction. The stepped pressure reduction and recovery module 6 includes a first sealing assembly 6.1, a leakage collection chamber 6.2, and a second sealing assembly 6.3 arranged sequentially along the leakage direction. The first sealing assembly 6.1 and the second sealing assembly 6.3 form flow resistance through a tight fit gap with the plunger 3, thereby generating a strong throttling effect on the light hydrocarbon media leaking along the plunger. This allows the first sealing assembly 6.1 to achieve initial flow obstruction and initial pressure reduction, while the second sealing assembly 6.3 achieves final interception and sealing of the residual media after pressure relief in the leakage collection chamber 6.2. The leakage collection chamber 6.2 is formed by openings in the casing 2. The channel is connected to the medium return check valve 7 to collect the light hydrocarbon medium after the initial pressure reduction, and to guide the medium back through the check valve when the pressure in its cavity exceeds a preset value; the active hydraulic barrier module 8 includes a lubricating oil chamber 8.1 and a third sealing assembly 8.2 located at the rear end of the stepped pressure reduction and recovery module 6; the lubricating oil chamber 8.1 is connected to an external oil station 11 through a lubricating oil suction connector 9 and a lubricating oil discharge connector 10 opened on the plenum 2, forming a circulating cooling circuit for the lubricating oil; the oil station 11 injects system lubricating oil into the lubricating oil chamber 8.1 at a pressure higher than the pressure of the light hydrocarbon medium at the inlet of the pump body 1, thereby forming a dynamic hydraulic barrier pointing towards the stepped pressure reduction and recovery module 6; the third sealing assembly 8.2 is located at the rear end of the lubricating oil chamber 8.1 to seal the system lubricating oil to maintain the stability of the dynamic hydraulic barrier and to serve as the final sealing interface of the closed-loop sealing system facing the atmosphere; the stepped pressure reduction and recovery module 6 and the active hydraulic barrier module 8 work together to form a bidirectional barrier closed-loop sealing system.

[0017] The medium return check valve 7 is connected to the inlet manifold of the light hydrocarbon medium storage tank 12 through a pipeline, forming a recovery path for the leaked medium.

[0018] The oil station 11 includes an oil pump 11.1, the outlet pressure of which is configured to be higher than the light hydrocarbon medium pressure at the inlet of the pump body 1, so that a positive pressure barrier is formed at the lubricating oil chamber 8.1 pointing to the stepped pressure reduction and recovery module 6.

[0019] The circulating cooling circuit also includes a cooling module 11.3 for dissipating heat from the returning lubricating oil. The cooling module 11.3 is located downstream of the lubricating oil discharge connector 10 and upstream of the lubricating oil chamber 8.1. Preferably, the cooling module 11.3 is an air-cooled unit.

[0020] The first sealing assembly 6.1, the second sealing assembly 6.3, and the third sealing assembly 8.2 all contain multiple layers of axially stacked sealing packing, and flow-blocking rings are provided between adjacent packing to enhance the rigidity of the packing and make its compression more uniform.

[0021] Inside the plenum 2, on the medium inflow side of the stepped pressure reduction and recovery module 6, there is also an elastic wear compensation component 13, which is used to apply axial preload to the sealing components in the stepped pressure reduction and recovery module 6 and the active hydraulic sealing module 8. This preload is also configured to balance the radial component of the force generated by the high-pressure light hydrocarbon medium, which causes the sealing components to tend to deflect, thereby continuously maintaining the alignment and sealing contact of the sealing components during the reciprocating motion of the plunger 3.

[0022] The duct 2 is also provided with an axial guide and support module 14, which includes a front guide part 14.1 and a rear guide part 14.2. The front guide part 14.1 is located between the elastic wear compensation part 13 and the stepped pressure reduction and recovery module 6, and the rear guide part 14.2 is located on the medium outflow side of the active hydraulic sealing module 8 and is axially fixed by a clamping nut 15. Preferably, the front guide part 14.1 is a front guide sleeve and the rear guide part 14.2 is a rear guide sleeve.

[0023] The axial distance between the end face of the plunger running chamber 1.1 and the mounting plane of the inlet valve 4 and the outlet valve 5 is 2-5 mm, which is a micro-gap structure to minimize the residual volume in the chamber. This suppresses the vaporization of light hydrocarbon media caused by drastic pressure changes during the reciprocating motion of the plunger 3 and ensures that the reciprocating pump maintains high volumetric efficiency.

[0024] The pump body 1 has a multi-cylinder structure. The stepped pressure reduction and recovery module 6 and the active hydraulic sealing module 8 are integrated in the cavity 2 of each cylinder in a one-to-one correspondence, forming multiple sets of parallel closed-loop sealing systems.

[0025] 1. Pump body structural system Pump body 1 adopts a multi-cylinder arrangement structure, and the number of cylinders can be selected in 1 / 2 / 3 / 5 / 7 / 9 according to the working conditions. The A-side of pump body 1 has a plunger running chamber 1.1 and a plunger 3 disassembly and assembly hole, which are sealed by a plug with a front flange 16. The B-side of pump body 1 is connected to the power end body using a reverse-pull connection structure. Specifically, threaded holes are machined on pump body 1, and through holes are provided on the body. Bolts and nuts are used for tightening and fixing. Vertical or horizontal structures can be selected according to different discharge pressures to ensure that the peak value of alternating pressure does not cause cracking of pump body 1.

[0026] The pump body 1 is centered around a plunger operating chamber 1.1, with an inlet valve 4 at the bottom and a drain valve 5 at the top. A key structural parameter is that a 2-5 mm axial gap is maintained between the end face of the plunger operating chamber 1.1 and the mounting plane of the inlet / drain valve 5. This structure effectively suppresses the vaporization of light hydrocarbon media and ensures high volumetric efficiency.

[0027] 2. Sealing system of the plenum body 2 The plenum 2 is positioned by precisely fitting its large outer diameter with the inner hole of the pump body, ensuring the coaxiality of the power end and the hydraulic end. The plenum 2 is fixed to the mounting step of the pump body 1 by bolts, forming a stable connection base.

[0028] The following are arranged sequentially along the axial direction inside the function 2: The elastic wear compensation component 13, specifically a compensation spring, is located at the front end of the sealing system; The front guide sleeve is positioned close to the rear end of the compensation spring. The stepped-down recovery module 6 includes: The first sealing assembly 6.1 typically consists of 4-6 pieces, depending on the pressure rating. A media buffer ring serves as a leakage collection chamber 6.2; Section 2 Sealing Assembly 6.3; Active hydraulic barrier module 8 includes: The lubricating oil ring serves as the lubricating oil cavity 8.1; Section 3 Sealing Assembly 8.2; The rear guide sleeve is located at the end of the sealing system; The clamping nut 15 is threaded to the rear end of the funnel body 2; 3. Auxiliary system connection relationships The medium return check valve 7 is connected to the medium buffer ring through the channel inside the body 2, and is connected to the inlet manifold of the storage tank through an external pipeline to form a leakage medium recovery path. Electric valves and manual valves are respectively installed on this pipeline.

[0029] The lubricating oil suction connector 9 and the lubricating oil discharge connector 10 are respectively located at the upper and lower positions of the small outer circle of the plenum 2, connected to the lubricating oil ring, and connected to the oil station 11 through an external pipeline to form a complete circulating cooling circuit.

[0030] The oil station 11 includes an oil sump 11.2, an oil pump 11.1 and a cooler. The outlet pressure of the oil pump 11.1 is set to 2.5 MPa, which is higher than the pressure of the light hydrocarbon medium at the inlet of the pump body 1, to ensure the formation of an effective hydraulic barrier.

[0031] 4. Key structural fit-in relationships The compensating spring applies a continuous axial preload to the entire sealing system, and the force is evenly transmitted through the front guide sleeve. The clamping nut 15 is threaded to the rear end of the housing 2, and the rear guide sleeve is used to axially clamp the sealing system and adjust the clearance.

[0032] Each sealing component forms a multi-stage sealing pair with the plunger 3. The medium buffer ring and the lubricating oil ring form annular gap spaces with the outer circle of the plunger 3, realizing the functions of medium collection and lubricating oil circulation.

[0033] This structural system, through precise axial arrangement and reasonable connection, enables the coordinated operation of the stepped pressure reduction and recovery module 6 and the active hydraulic barrier sealing module 8, forming a complete bidirectional barrier sealing system.

[0034] Installation process: First, using the inner bore of the power unit as a reference, determine the centerline of each cylinder. After aligning the pump body 1B surface with the end face of the unit, use a reverse-pull connection structure for fixation, i.e., bolts are inserted from the side of the unit and mate with the threaded holes of the pump body 1, then tightened with nuts. Next, mate the large outer diameter of the casing 2 with the inner bore of the unit, ensuring its end face aligns with the concave stepped reference hole of the pump body 1, then tighten the bolts. The sealing system assembly begins at the rear end of the casing 2, sequentially installing the rear guide sleeve, the third sealing assembly 8.2, the lubricating oil ring, the second sealing assembly 6.3, the media buffer ring, the first sealing assembly 6.1, the front guide sleeve, and the compensation spring. Finally, screw in the clamping nut 15 and apply axial preload to the sealing system through the rear guide sleeve. After completing the sealing system assembly, install the media return check valve 7 and connect it to the storage tank inlet manifold. Then connect the lubricating oil suction connector 9 and discharge connector to the corresponding pipelines of the oil station 11. The plunger 3 is inserted into the assembled manifold 2 sealing system through the disassembly hole on the pump body 1A side. Then, the inlet valve 4 and its sleeve are installed at the lower position, and the drain valve 5 and its discharge sleeve are installed at the upper position. Finally, the pump body 1A side is sealed with a plug featuring a front flange 16. After connecting the storage tank and the inlet manifold, the oil station 11 cooling system and related testing instruments are installed. Finally, the installation accuracy is verified, including using a dial indicator to check the coaxiality of the plunger 3 and the inner bore of the manifold 2, verifying that the axial clearance between the plunger running chamber 1.1 end face and the valve mounting plane is within the range of 2-5 mm, and fine-tuning the sealing preload by tightening the nut 15. Finally, after manually turning the plunger 3 to confirm smooth movement, the protective device is installed to complete the entire installation process.

[0035] Workflow: Phase 1: Initial State Establishment 1. System pre-pressure establishment: Start oil station 11, oil pump 11.1 pressurizes lubricating oil to 2.5MPa, injects it into the lubricating oil ring through lubricating oil suction joint 9, and establishes a working pressure higher than that on the medium side in the active hydraulic barrier module 8.

[0036] 2. Sealing preload setting: The compensating spring applies an initial axial preload to the entire sealing system to ensure that each sealing component maintains adequate contact with the plunger 3.

[0037] Phase Two: Normal Delivery Process 3. Suction process: The plunger 3 moves backward, the inlet valve 4 opens, the outlet valve 5 closes, and the light hydrocarbon medium is sucked from the storage tank into the plunger operating chamber 1.1.

[0038] 4. Discharge process: The plunger 3 moves forward, the inlet valve 4 closes, the volume of the plunger running chamber 1.1 decreases and the pressure increases, the discharge valve 5 opens, and the light hydrocarbon medium is pressurized and discharged.

[0039] Phase 3: Leakage Media Handling Process 5. Primary sealing and pressure reduction: If light hydrocarbon medium leaks along plunger 3, it first enters the first sealing assembly 6.1. After passing through multiple packings to gradually impede the flow, the medium pressure and flow rate are significantly reduced.

[0040] 6. Media collection and buffering: The leaked media, after initial depressurization, enters the media buffer ring and temporarily accumulates.

[0041] 7. Pressure Judgment and Backflow: When the pressure of the medium accumulated in the buffer ring exceeds the inlet pressure of the storage tank (set value 1.6MPa), the medium backflow check valve 7 will open automatically.

[0042] 8. Safe return of media: The leaked light hydrocarbon media is safely returned to the inlet manifold or storage tank through the return check valve and connecting pipeline, completing the closed-loop recovery of the media.

[0043] Phase 4: Active Blockade Maintenance Process 9. Hydraulic barrier establishment: Oil station 11 continuously maintains a working pressure of 2.5MPa within the lubricating oil ring, forming a stable dynamic hydraulic sealing barrier.

[0044] 10. Bidirectional barrier: This hydraulic barrier effectively prevents any light hydrocarbon medium from penetrating backward, and at the same time forms a bidirectional barrier effect in synergy with the front-end stepped depressurization and recovery module 6.

[0045] Phase 5: System Status Maintenance Process 11. Thermal management cycle: The lubricating oil returning from the lubricating oil discharge joint 10 is cooled by the cooler and then returned to the oil sump 11.2 to maintain the lubricating oil at a suitable working temperature.

[0046] 12. Automatic wear compensation: During the reciprocating motion of the plunger 3, the compensation spring continuously applies axial preload to the sealing system, automatically compensating for the wear of the sealing components.

[0047] 13. Operational stability assurance: The front guide sleeve and the rear guide sleeve ensure the accuracy of the piston 3's movement trajectory, and the clamping nut 15 provides stable axial fixation.

[0048] Phase 6: System Coordination and Operation 14. Module Collaborative Operation: The stepped pressure reduction and recovery module 6 and the active hydraulic barrier sealing module 8 work together in real time to form a complete bidirectional barrier sealing system.

[0049] 15. Continuous leak-free operation: Through the cyclical execution of the above process, zero external leakage of light hydrocarbon media is achieved throughout the high-pressure transportation process, ensuring long-term stable and reliable operation of the equipment.

[0050] This workflow, through the precise coordination of various functional modules and systematic process control, achieves fully automated management of the entire process from media transportation and leakage control to system maintenance, effectively solving the leakage problem in high-pressure transportation of light hydrocarbon media.

[0051] The above description only illustrates the preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All modifications made within the scope of the independent claims of this invention are also within the scope of protection of this invention.

Claims

1. A leak-free reciprocating pump device for conveying light hydrocarbon media, comprising a pump body (1), a casing (2) disposed on the pump body (1), and a plunger (3) passing through the casing (2) and reciprocating, wherein the pump body (1) is provided with a plunger operating chamber (1.1) communicating with the front end of the plunger (3), and an inlet valve (4) and a drain valve (5), characterized in that: The following are arranged sequentially along the axial direction inside the functional body (2): The stepped pressure reduction and recovery module (6) includes a first sealing assembly (6.1), a leakage collection chamber (6.2), and a second sealing assembly (6.3) arranged sequentially along the direction of medium leakage; The first sealing assembly (6.1) and the second sealing assembly (6.3) form a flow resistance through the tight fit gap between them and the plunger (3), thereby generating a strong throttling effect on the light hydrocarbon medium leaking along the plunger, so that the first sealing assembly (6.1) achieves initial flow obstruction and initial pressure reduction, and the second sealing assembly (6.3) achieves final interception and sealing of the residual medium after the pressure is released in the leakage collection chamber (6.2); The leakage collection chamber (6.2) is connected to the medium return check valve (7) through a channel opened on the body (2) to collect the light hydrocarbon medium after the first pressure reduction, and guide the medium back through the check valve when the pressure in the chamber exceeds a preset value; The active hydraulic barrier module (8) includes a lubricating oil chamber (8.1) and a third sealing assembly (8.2) located at the rear end of the stepped pressure reduction and recovery module (6). The lubricating oil chamber (8.1) is connected to an external oil station (11) through a lubricating oil inlet joint (9) and a lubricating oil outlet joint (10) opened on the plenum (2), forming a circulating cooling circuit for lubricating oil. The oil station (11) injects system lubricating oil into the lubricating oil chamber (8.1) at a pressure higher than that of the light hydrocarbon medium at the inlet of the pump body (1), thereby forming a dynamic hydraulic barrier pointing towards the stepped pressure reduction and recovery module (6). The third sealing assembly (8.2) is located at the rear end of the lubricating oil chamber (8.1) and is used to seal the lubricating oil of the system to maintain the stability of the dynamic hydraulic barrier and serve as the final sealing interface of the closed-loop sealing system facing the atmosphere. The stepped pressure reduction and recovery module (6) and the active hydraulic sealing module (8) work together to form a closed-loop sealing system for bidirectional sealing.

2. The leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 1, characterized in that: The medium return check valve (7) is connected to the inlet manifold of the light hydrocarbon medium storage tank (12) through a pipeline, forming a recovery path for the leaked medium.

3. The leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 1, characterized in that: The oil station (11) includes an oil pump (11.1) whose outlet pressure is configured to be higher than the light hydrocarbon medium pressure at the inlet of the pump body (1), thereby forming a positive pressure barrier at the lubricating oil chamber (8.1) pointing towards the stepped pressure reduction and recovery module (6).

4. A leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 1, characterized in that: The circulating cooling circuit also includes a cooling module (11.3) for dissipating heat from the returning lubricating oil. The cooling module (11.3) is located downstream of the lubricating oil discharge connector (10) and upstream of the lubricating oil chamber (8.1).

5. A leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 1, characterized in that: The first sealing assembly (6.1), the second sealing assembly (6.3), and the third sealing assembly (8.2) all contain multiple layers of axially stacked sealing packing, and flow-blocking rings are provided between adjacent packing to enhance the rigidity of the packing and make its compression more uniform.

6. A leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 1, characterized in that: The body (2) is also provided with an elastic wear compensation component (13) on the medium inflow side of the stepped pressure reduction and recovery module (6), which is used to apply an axial preload to the sealing components in the stepped pressure reduction and recovery module (6) and the active hydraulic sealing module (8). The preload is also configured to balance the radial component of the sealing component caused by the high pressure light hydrocarbon medium, thereby maintaining the alignment and sealing contact of the sealing component during the reciprocating motion of the plunger (3).

7. A leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 6, characterized in that: The duct (2) is also provided with an axial guide and support module (14), which includes a front guide part (14.1) and a rear guide part (14.2). The front guide part (14.1) is located between the elastic wear compensation part (13) and the stepped pressure reduction and recovery module (6). The rear guide part (14.2) is located on the medium outflow side of the active hydraulic sealing module (8) and is axially fixed by a clamping nut (15).

8. A leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 1, characterized in that: The axial distance between the end face of the plunger running chamber (1.1) and the mounting plane of the inlet valve (4) and the outlet valve (5) is 2-5 mm, which is a micro-gap structure to minimize the residual volume in the chamber, thereby suppressing the vaporization phenomenon of light hydrocarbon medium caused by drastic pressure changes during the reciprocating motion of the plunger (3) and ensuring that the reciprocating pump maintains high volumetric efficiency.

9. A leak-free reciprocating pump device for conveying light hydrocarbon media according to claim 1, characterized in that: The pump body (1) has a multi-cylinder structure. The stepped pressure reduction and recovery module (6) and the active hydraulic sealing module (8) are integrated in the cavity (2) of each cylinder in a one-to-one correspondence manner, forming multiple sets of parallel closed-loop sealing systems.

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