A self-balancing smooth rod seal

Abstract

This utility model discloses a self-balancing polished rod seal, comprising an upper packing, a piston, and a lower packing. An upper packing mounting body one, equipped with a fluid transmission hole, contains an upper partition, an upper packing, and a lower partition. The upper packing mounting body one is connected to an upper packing mounting body two. A pressure cap, pressed against the upper partition, and the piston are connected outside the upper packing mounting body one and can move along a piston sleeve corresponding to the fluid transmission hole, connected to the outside of both upper packing mounting bodies one and two. A pressure ring is installed on the upper end of the lower packing, which is installed in the lower packing mounting body. This utility model is a polished rod seal capable of automatically improving the stress state of the upper packing, especially convenient for use in the lower packing for maintenance or replacement of the upper packing. This polished rod seal can be manufactured in different specifications and sizes, with series processing and manufacturing to meet and adapt to different specifications of polished rods installed in different oil wells, and is particularly suitable for oil wells with severe wear or large pressure differences between the inside and outside of the well.

Description

Technical Field

[0001] This utility model pertains to wellhead sealing devices for oil pumping units in the field of oilfield development, specifically a self-balancing polished rod sealer. Background Technology

[0002] In current oilfield development operations, rod pump wells still account for a considerable proportion. As an indispensable key device in rod pump oil production systems, the performance of the polished rod seal directly affects the well's extraction efficiency, as well as the efficiency and labor intensity of the workers' well management.

[0003] Currently, most polished rod seals used in oilfields require regular manual packing tightening to ensure a tight seal between the packing and the polished rod, thereby extending the effective service life of the packing. This is necessary because the core sealing component of the polished rod seal—the packing—operates in an extremely harsh environment. This harsh environment stems from two factors: firstly, the packing must withstand high-pressure impacts from inside the tubing; secondly, it must endure the clamping force applied by the pressure cap.

[0004] Meanwhile, the friction generated by the reciprocating motion of the polished rod, as well as the uneven wear caused by the polished rod deviating from the center of the wellhead, will cause serious damage to the packing.

[0005] Furthermore, changes in environmental factors, such as temperature and chemical corrosion, can also adversely affect packing materials made of rubber, further accelerating their aging and wear. Therefore, optimizing the stress state of the packing and reducing the various stresses it bears during operation is undoubtedly the key to extending the service life of the packing and improving the working efficiency of the polished rod seal.

[0006] To address the problems existing in polished rod seals, the following related patent technologies have emerged: Patent application number CN201910146875.5 discloses an oilfield polished rod seal, which includes a pressure cap, an upper packing cylinder, an oil injection cylinder, an oil injector, a connecting cylinder, a lower packing cylinder, and an adjustment device. The pressure cap is threadedly connected to the upper end of the upper packing cylinder. An upper packing is provided inside the upper packing cylinder. An upper goggle is provided at the upper end of the upper packing. The upper end of the upper goggle is connected to the pressure cap, and the lower end of the upper goggle is connected to the upper packing. The lower end of the upper packing is provided with a partition, and a friction sealing ring is sleeved on the inner side of the partition. The lower end of the upper packing cylinder is connected to an oil injection cylinder, and an oil holding tank is connected to the side wall of the oil injection cylinder. An oil injector is provided on the oil holding tank. The lower end of the oil injection cylinder is connected to the upper end of the lower packing cylinder through a connecting cylinder. The lower packing cylinder is provided with a lower packing. The upper end of the lower packing is provided with a lower golan, and the upper end of the lower golan is connected to the lower end of the connecting cylinder. Adjustment devices are provided on the lower inner walls of both the upper and lower packing cylinders.

[0007] The advantages of the above invention are that the traditional sealing structure with added oil injection cylinder reduces packing wear and improves lubrication, and the constraint spring prevents piston wobbling, ensuring the piston's stability when not in use. However, it does not solve the problem of uneven force distribution on the packing, and the service life of the packing is still not long.

[0008] The magnetic pressure-boosting polished rod seal disclosed in patent application CN201610372660.1 is used for sealing the polished rod at the wellhead of a beam pumping unit in an oilfield. It solves the long-standing problems of high frictional resistance, frequent leakage, and environmental pollution associated with various polished rod seals. Its structural feature is that within a cylindrical polished rod sealing chamber, a fixed sealing sleeve with six embedded strip-shaped permanent magnets is installed at the lower end, and a sliding sealing sleeve with six embedded strip-shaped permanent magnets is installed at the upper end. The space between the upper and lower sealing sleeves is filled with magnetic fluid packing. Under the strong magnetic field attraction generated by the 12 oppositely positioned permanent magnets, the sliding sealing sleeve maintains the potential energy to slide towards the fixed sealing sleeve, thus firmly adsorbing and compressing the magnetic fluid packing to form a expandable high-pressure sealing zone. This liquid-lubricated, highly lubricated seal can effectively and persistently seal the polished rod, achieving energy conservation and emission reduction, eliminating oil, gas, and water leakage, eliminating the need for packing replacement, reducing downtime losses, eliminating safety hazards, improving environmental quality, and contributing to the development of green oilfields.

[0009] The aforementioned patented technology employs magnetic fluid pressurized sealing; however, actual magnetic fluid packing seals require operation in a precise, dust-free environment, making them unsuitable for field production in oilfields. Furthermore, the magnetic pressurized polished rod sealer suffers from the problem of not being able to temporarily seal the lower part when addressing issues at the top. Therefore, the aforementioned patented technology still fails to adequately solve the problems of wellhead sealing, alignment, and uneven packing stress in oil wells.

[0010] Patent application CN202010302545.3 discloses an automatic packing gland sealer, belonging to the technical field of oilfield production equipment. It includes a packing gland cap and a packing gland box connected to the cap. The packing gland box contains a packing gland, a hydraulic piston, and a piston cap. The piston cap, hydraulic piston, and packing gland box together form an upper sealing oil chamber. A lower sealing oil chamber is located inside the packing gland box below the packing gland. Pressurized oil from the oil well flows sequentially into the lower and upper sealing oil chambers through a gap. This invention conveniently introduces pressurized oil from the lower sealing oil chamber into the upper sealing oil chamber. The pressurized oil directly acts on the upper surface of the hydraulic piston, automatically pressurizing and sealing the packing gland under the pressure of the oil. This avoids excessive wear on the packing gland caused by manually increasing the preload, thus improving the packing gland's service life. It is also low-cost to manufacture and safe.

[0011] However, the aforementioned inventions are relatively complex in structure, relatively expensive to manufacture, and prone to malfunctions during use, and can still be further improved. Summary of the Invention

[0012] The purpose of this invention is to provide a self-balancing polished rod seal, solving the problems of short service life caused by uneven stress on the packing of existing polished rod seals, as well as the heavy workload and arduous tasks of daily maintenance for oilfield workers. This extends the service life of the packing, reduces the labor intensity of oilfield workers, and improves work efficiency.

[0013] The technical solution of this utility model is: a self-balancing polished rod sealer, comprising an upper packing, a piston, and a lower packing, wherein: an upper partition, an upper packing, and a lower partition are installed in an upper packing mounting body one with a fluid transmission hole, and the upper packing mounting body one is connected to an upper packing mounting body two; a pressure cap and a piston, which are pressed onto the upper partition, are connected outside the upper packing mounting body one and can move along a piston sleeve that is connected to the outside of the upper packing mounting body one and the upper packing mounting body two corresponding to the fluid transmission hole; a pressure ring is installed on the upper end of the lower packing installed in the lower packing mounting body; the connection between the upper packing mounting body two and the lower packing mounting body forms a seal on the polished rod, and gas and liquid in the well can enter the piston chamber along the fluid transmission hole.

[0014] Preferably, both the first and second upper packing units are non-uniform diameter cylindrical bodies, and the outer circle after the connection of the two is provided with a pressure cap suspension step and a piston assembly step from top to bottom; the upper inner circle after the connection of the first and second upper packing units is smaller than the middle inner circle and the middle inner circle is smaller than the lower inner circle. The upper inner circle is the packing sealing cavity, the annular space formed by the middle inner circle and the smooth rod is the gas-liquid flow cavity, and the lower inner circle is the connection cavity with the lower packing unit equipped with the pressure ring and the lower packing.

[0015] Preferably, the pressure cap suspension step is disposed in the upper packing mounting body and the outer circle of the pressure cap suspension step is provided with a sealing ring groove and a sealing ring is installed; the piston sleeve assembly step is formed by three-level assembly steps: upper, middle and lower, and a liquid transmission hole is provided in the upper assembly step of the upper packing mounting body, a sealing ring groove is provided in the middle assembly step or in the inner cavity of the piston sleeve and a sealing ring is installed, and an external thread is provided in the lower assembly step and can be connected to the internal thread of the piston sleeve.

[0016] Preferably, an upper partition, an upper packing, and a lower partition are installed sequentially from top to bottom in the packing sealing cavity of the upper inner circle of the upper packing mounting body one. After the upper packing mounting body one and the upper packing mounting body two are connected, they communicate with the gas-liquid flow cavity and the liquid transmission hole between them and the smooth rod, the annular gap between the piston sleeve and the piston sleeve fitting step, and the piston cavity.

[0017] Preferably, the first upper packing mounting body is threadedly connected to the second upper packing mounting body. The upper end cavity surface of the connecting cavity on the upper inner circle of the second upper packing mounting body is provided with an arc-shaped groove that matches the upper outer circle of the pressure ring, and the lower inner circle is provided with an internal thread that is threadedly connected to the lower packing mounting body.

[0018] Preferably, the piston sleeve 8 is a non-uniform diameter cylindrical body with an upper outer circle smaller than the lower outer circle, and the upper outer circle is the piston sliding section; the lower inner circle of the piston sleeve mates with the lower mounting step on the outside of the upper packing body 2 and is threadedly connected.

[0019] Preferably, the pressure ring is a cylinder with a through hole for the light rod, and the upper outer circle is larger than the lower outer circle and the outer circle of the lower packing. The upper outer circle of the pressure ring cooperates with the arc-shaped groove provided on the upper end cavity surface of the connecting cavity in the upper inner circle of the upper packing mounting body and can press against the upper end surface of the lower packing mounting body.

[0020] Preferably, the upper partition is a cylindrical body with a smooth rod through hole and a U-shaped cross-section, and the outer circle of the upper partition and the packing sealing cavity of the upper packing mounting body are in clearance fit.

[0021] Preferably, one or more liquid transfer holes are provided.

[0022] Preferably, the lower inner and outer circles of the lower packing mounting body are both threaded and can be respectively connected to the adjusting ball rod in the lower adjusting device and the upper packing mounting body.

[0023] Compared with the prior art, the significant advantages of this utility model are:

[0024] 1. This utility model is a smooth rod seal that can self-balance force and automatically improve the stress state of the upper packing, which greatly extends the service life of the upper and lower packings, especially the lower packing is convenient for maintenance or replacement of the upper packing.

[0025] 2. This device is equipped with a primary sealing mechanism, a self-balancing mechanism, and a secondary sealing mechanism. The self-balancing mechanism works in conjunction with the primary sealing mechanism to balance the stress on the upper and lower partitions, thereby improving the working condition of the upper packing. The secondary sealing mechanism is located below the primary sealing mechanism. When the upper packing in the primary sealing mechanism needs to be replaced, the lower packing in the secondary sealing mechanism is used to seal the smooth rod.

[0026] 3. In this device, hydraulic pressure is transmitted to the piston chamber through the fluid transmission hole. The piston converts the pressure into a downward clamping force. Through the linkage of the fluid transmission hole, piston chamber, and piston, the pressure in the tubing inside the well is converted into downward hydraulic pressure in real time, dynamically balancing the upper and lower forces on the packing. This eliminates the local stress concentration on the packing caused by uneven stress in traditional seals, significantly extending the service life of the packing from 3 months in traditional seals to 36 months or more. One set of this device was manufactured in the applicant's oilfield machining workshop on October 9, 2023, and installed on the He 148-Xie 34 oil well for testing. As of the application date, it has been in normal production for 660 days without ever over-tightening the upper packing. No oil carryover or leakage has occurred at the wellhead of the production well, and production and use are normal. The test proves that this device can effectively solve the problem of frequently tightening the wellhead polished rod seal.

[0027] 4. In this utility model, the pressure cap of the primary sealing mechanism is threadedly connected to the piston; the piston can move up and down outside the piston sleeve that is threadedly connected to the upper packing mounting body II, and the upper packing mounting body II is threadedly connected to the lower packing mounting body, forming a modular assembly structure that supports quick disassembly and maintenance. This device can reduce the complexity of on-site packing replacement operations by 50%.

[0028] 5. This utility model can be manufactured in different specifications and sizes, and processed and manufactured in series to meet and adapt to different specifications of polished rods installed in different oil wells.

[0029] 6. Because this invention can effectively extend the working life of the polished rod seal, it significantly reduces the labor intensity of employees, reduces well shutdown and replacement time, and improves the well opening rate. This invention is applicable to oil wells produced by conventional rod pumping systems, especially oil wells with severe wear or large pressure differentials between the inside and outside of the well.

[0030] In conclusion, this utility model has significant effects and can bring obvious economic benefits, and has promotion and application value. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0032] Figure 1 This is a schematic diagram of the structure of this utility model.

[0033] In the picture:

[0034] 1. Smooth rod, 2. Upper partition, 3. Pressure cap, 4. Upper packing, 5. Upper packing mounting body 1, 5. Liquid transfer hole 5-1, Piston, 6. Lower partition, 7. Piston sleeve, 8. Upper packing mounting body 2, 9. Pressure ring, 10. Lower packing, 11. Lower packing mounting body, 12. Piston chamber, 13. Upper adjustment body, 14. Lower adjustment body, 15. Adjustment ball rod, 16. Detailed Implementation

[0035] The accompanying drawings are for reference and illustration only and are not intended to limit the scope of protection of this utility model. The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0037] In the description of this utility model, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," 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 utility model and simplifying the description, and do not 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 utility model. Furthermore, in the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] See Figure 1 A self-balancing smooth rod seal includes an upper packing 4, a piston 6, and a lower packing 11, wherein:

[0039] The upper packing mounting body 1 5, which has a liquid transfer hole 5-1, is equipped with an upper partition 2, an upper packing 4 and a lower partition 7. The upper packing mounting body 1 5 is connected to the upper packing mounting body 2 9.

[0040] The pressure cap 3 and piston 6, which are pressed onto the upper partition 2, are connected to the outside of the upper packing mount 1 5 and can move along the piston sleeve 8, which is connected to the outside of the upper packing mount 1 5 and the upper packing mount 2 9, corresponding to the liquid transfer hole 5-1.

[0041] A pressure ring 10 is installed on the upper end of the lower packing 11 installed in the lower packing mounting body 12;

[0042] The upper packing unit 29 and the lower packing unit 12 are connected to form a seal on the polished rod 1, allowing gas and liquid in the well to enter the piston chamber 13 along the liquid transmission hole 5-1. This keeps the piston 6 in a state of pressing the upper packing 4 downwards against the pressure cap 3 and the upper partition 2, with the upper packing 4 always in a self-balancing state.

[0043] In this utility model, a primary sealing mechanism and a secondary sealing mechanism are provided. The primary sealing mechanism mainly consists of an upper partition 2, a lower partition 7 and an upper packing 4 installed in the upper packing mounting body 5. The upper partition 2 and the lower partition 7 seal the upper packing 4 in the annular space formed by the smooth rod 1 and the upper packing mounting body 5, thereby achieving a seal on the smooth rod 1.

[0044] The secondary sealing mechanism is located below the primary sealing mechanism and mainly consists of a pressure ring 10 pressed onto the lower packing 11, the lower packing 11, and the lower packing mounting body 12. When the upper packing 4 needs to be replaced, the upper packing mounting body 2 9 can be rotated to move the upper packing mounting body 1 5 downward, thereby causing the upper packing mounting body 2 9 to press down on the pressure ring 10, which in turn presses down on the lower packing 11 inside the lower packing mounting body 12, thus sealing the polished rod 1 and sealing the lower pressure.

[0045] In this invention, the pressure cap 3, piston 6, piston sleeve 8, and upper packing mounting body 1 5 form a self-balancing mechanism. The piston 6 and piston sleeve 8, together with the upper packing mounting body 1 5 and upper packing mounting body 2 9, form a piston chamber 13. When the internal pressure of this device is greater than atmospheric pressure, the piston 6 will generate a downward hydraulic pressure under the pressure difference in the piston chamber 13. This hydraulic pressure is transmitted to the upper partition 2 through the pressure cap 3, thereby improving the stress state of the upper packing 4.

[0046] Based on the above embodiment one, the present invention also has the following embodiments:

[0047] In a preferred embodiment: both the upper packing mounting body 1 5 and the upper packing mounting body 2 9 are non-uniform diameter cylindrical bodies, and the outer circle after the connection of the two is provided with a pressure cap suspension step and a piston assembly step from top to bottom; the upper inner circle after the connection of the upper packing mounting body 1 5 and the upper packing mounting body 2 9 is smaller than the middle inner circle and the middle inner circle is smaller than the lower inner circle. The upper inner circle is the packing sealing cavity, the annular space formed by the middle inner circle and the smooth rod 1 is the gas-liquid flow cavity, and the lower inner circle is the connection cavity with the lower packing mounting body 12 which is equipped with the pressure ring 10 and the lower packing 11.

[0048] In a preferred embodiment: the pressure cap suspension step is disposed in the upper packing mounting body 5, and the outer circumference of the pressure cap suspension step is provided with a sealing ring groove and a sealing ring is installed; the piston sleeve assembly step is formed by three-level assembly steps: upper, middle and lower, and a liquid transmission hole 5-1 is provided in the upper assembly step of the upper packing mounting body 5; a sealing ring groove is provided in the middle assembly step or in the inner cavity of the piston sleeve 8 and a sealing ring is installed; and an external thread is provided in the lower assembly step and can be connected to the internal thread of the piston sleeve 8.

[0049] In a preferred embodiment: The upper partition 2, upper packing 4, and lower partition 7 are sequentially installed from top to bottom in the packing sealing cavity of the upper inner circle of the upper packing mounting body 1 5. After the upper packing mounting body 1 5 and the upper packing mounting body 2 9 are connected, they communicate with the gas-liquid flow cavity and the fluid transmission hole 5-1 between them and the polished rod 1, the annular gap between the piston sleeve 8 and the piston sleeve mating step, and the piston cavity 13. Gas and fluid from the well can enter the piston cavity 13 through the gas-liquid flow cavity formed between the upper packing mounting body 1 5 and the upper packing mounting body 2 9 and the polished rod 1, the fluid transmission hole 5-1, and the annular gap in the piston sleeve 8 and the piston sleeve mating step. This pulls the piston 6 and the pressure cap 3 downwards, pressing the upper partition 2 and the upper packing 4, keeping the upper packing 4 in a state of automatic internal and external pressure balance, greatly extending the service life of the upper packing 4. A set of this device, processed in the machining workshop of an oilfield, was installed in an oil well for trial use. It was demonstrated that the upper packing 4 has a service life of two years and is still functioning normally. It is expected to be able to be used for three years or more.

[0050] In a preferred embodiment: the upper packing mounting body 1 5 is threadedly connected to the upper packing mounting body 2 9. The upper end cavity surface of the connecting cavity on the upper inner circle of the upper packing mounting body 2 9 is provided with an arc-shaped groove that matches the upper outer circle of the pressure ring 10, and the lower inner circle is provided with an internal thread that is threadedly connected to the lower packing mounting body 12.

[0051] In a preferred embodiment: the piston sleeve 8 is a non-uniform diameter cylindrical body with an upper outer circle smaller than the lower outer circle, and the upper outer circle is the piston sliding section; the lower inner circle of the piston sleeve 8 mates with the lower mounting step on the outside of the upper packing mounting body 9 and is threadedly connected.

[0052] In a preferred embodiment, the pressure ring 10 is a cylinder with a through hole for the light rod, and the upper outer circle is larger than the lower outer circle and the outer circle of the lower packing 11. The upper outer circle of the pressure ring 10 is matched with the arc-shaped groove provided on the upper end cavity surface of the connecting cavity in the upper inner circle of the upper packing mounting body 9 and can press against the upper end surface of the lower packing mounting body 12.

[0053] In a preferred embodiment, the upper partition 2 is a cylindrical body with a smooth rod through hole and a U-shaped cross-section, and the outer circle of the upper partition 2 and the packing sealing cavity of the upper packing mounting body 5 are in clearance fit.

[0054] In a preferred embodiment, one or more of the liquid transfer holes 5-1 are provided.

[0055] In a preferred embodiment, the lower inner and outer circles of the lower packing mounting body 12 are threaded and can be threadedly connected to the adjusting ball rod 16 in the lower adjusting device and the upper packing mounting body 9, respectively. The lower adjusting device of this utility model is prior art, which is provided with an upper adjusting body 14, a lower adjusting body 15, and an adjusting ball rod 16 with an adjusting ball head at the bottom. The upper adjusting body 14 and the lower adjusting body 15 are provided with ball cavities that match the adjusting ball head. After the adjusting ball rod 16 with the adjusting ball head is installed, the upper adjusting body 14 and the lower adjusting body 15 are threadedly connected. If it is used in conjunction with the upper smooth rod sealing device, the sealing effect of the upper smooth rod sealing device will be better.

[0056] This utility model can be used alone or in combination with an adjustment device. It is even more effective when used in oil wells with severe uneven wear, and the service life of the upper packing 4 and the lower packing 11 is longer.

[0057] The embodiments described above are merely typical examples, but the present invention is not limited to these embodiments. Those skilled in the art can make modifications without departing from the spirit and teachings of 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 inventive spirit and concept of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope is not limited to the above description.

Claims

1. A self-balancing polished rod seal comprising an upper packing, a piston, and a lower packing, characterized in that, The upper packing mounting body one, which has a fluid transmission hole, is equipped with an upper partition, an upper packing, and a lower partition. The upper packing mounting body one is connected to the upper packing mounting body two. The pressure cap and piston, which are pressed onto the upper partition, are connected to the outside of the upper packing mounting body one and can move along the piston sleeve, which is connected to the outside of the upper packing mounting body one and the upper packing mounting body two, corresponding to the fluid transmission hole. A pressure ring is installed on the upper end of the lower packing installed in the lower packing mounting body. The connection between the upper packing mounting body two and the lower packing mounting body forms a seal on the polished rod, and the gas and liquid in the well can enter the piston chamber along the fluid transmission hole.

2. A self-balancing polish rod seal as defined in claim 1, wherein, Both the first and second upper packing units are non-uniform diameter cylindrical bodies, and the outer circle after the connection of the two is provided with a pressure cap suspension step and a piston assembly step from top to bottom; the upper inner circle after the connection of the first and second upper packing units is smaller than the middle inner circle and the middle inner circle is smaller than the lower inner circle. The upper inner circle is the packing sealing cavity, the annular space formed by the middle inner circle and the smooth rod is the gas-liquid flow cavity, and the lower inner circle is the connection cavity with the lower packing unit equipped with the pressure ring and the lower packing.

3. A self-balancing polish rod seal as defined in claim 2 wherein, The pressure cap suspension step is set in the upper packing mounting body one, and the outer circle of the pressure cap suspension step is provided with a sealing ring groove and a sealing ring is installed; the piston sleeve assembly step is formed by three-level assembly steps: upper, middle and lower. The upper assembly step of the upper packing mounting body one is provided with a liquid transmission hole, the middle assembly step or the inner cavity of the piston sleeve is provided with a sealing ring groove and a sealing ring is installed, and the lower assembly step is provided with an external thread that can be connected to the internal thread of the piston sleeve.

4. A self-balancing smooth rod seal as described in claim 3, characterized in that, The upper partition, upper packing and lower partition are installed sequentially from top to bottom in the packing sealing cavity of the upper inner circle of the upper packing mounting body one. After the upper packing mounting body one and the upper packing mounting body two are connected, they are connected to the gas-liquid flow cavity and liquid transmission hole between the upper packing mounting body one and the smooth rod, the annular gap between the piston sleeve and the piston sleeve fitting step and the piston cavity.

5. A self-balancing smooth rod seal as described in claim 4, characterized in that, The upper packing mounting body one is threadedly connected to the upper packing mounting body two. The upper end cavity surface of the connecting cavity on the upper inner circle of the upper packing mounting body two is provided with an arc-shaped groove that matches the upper outer circle of the pressure ring, and the lower inner circle is provided with an internal thread that is threadedly connected to the lower packing mounting body.

6. A self-balancing smooth rod seal as described in claim 3, characterized in that, The piston sleeve (8) is a non-uniform diameter cylindrical body with an upper outer circle smaller than the lower outer circle. The upper outer circle is the piston sliding section. The lower inner circle of the piston sleeve is engaged with the lower mounting step on the outside of the upper packing body and is threadedly connected.

7. A self-balancing smooth rod seal as described in claim 5, characterized in that, The pressure ring is a cylinder with a through hole for the light rod, and the upper outer circle is larger than the lower outer circle and the outer circle of the lower packing. The upper outer circle of the pressure ring is matched with the arc-shaped groove provided on the upper end cavity surface of the connecting cavity in the upper inner circle of the upper packing mounting body and can press against the upper end surface of the lower packing mounting body.

8. A self-balancing smooth rod seal as described in claim 4, characterized in that, The upper partition is a cylindrical body with a smooth rod through hole and a U-shaped cross-section. The outer circle of the upper partition and the packing sealing cavity of the upper packing mounting body are in clearance fit.

9. A self-balancing smooth rod seal as described in claim 4, characterized in that, The liquid transfer hole is provided in one or more places.

10. A self-balancing smooth rod seal as described in claim 7, characterized in that, The lower inner and outer circles of the lower packing mounting body are both threaded and can be respectively connected to the adjusting ball rod in the lower adjusting device and the two threads of the upper packing mounting body.

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