Sealing structure of polished rod of pumping unit

Abstract

The utility model relates to the technical field of oil pumping unit polish rod, specifically disclose polish rod sealing structure of oil pumping unit, including sealing casing, the sealing casing top end place is covered with the coaxial distribution of pressure cap, the pressure cap inner top fixed surface is connected with the coaxial distribution of pressure pipe, the pressure pipe inboard wall fixed bonding has the coaxial distribution of cylindrical sealing packing, the pressure cap outer top fixed mounting has the exhaust pipe and the grease injection pipe, the sealing casing is provided with the coaxial distribution of conical sealing packing in, the sealing casing is vertically provided with the coaxial distribution of polish rod body, through the fixed and the communication exhaust pipe and grease injection pipe of pressure cap's outer top end face, when needing to inject the lubricating grease into the sealing casing, the air that can be retained in the sealing casing through the exhaust pipe and timely discharge, thereby effectively avoid the interference that the smooth injection of lubricating grease is caused because of the air pressure stagnation in the casing, guarantee the smoothness and reliability of grease injection operation.

Description

Technical Field

[0001] This utility model relates to the field of polished rod technology for oil pumping units, and in particular to the polished rod sealing structure for oil pumping units. Background Technology

[0002] In the surface-to-downhole connection system of a pumping unit, the polished rod is a key transmission and sealing component, undertaking the dual core roles of "power transmission" and "wellhead sealing," and serving as a "bridge" connecting the surface pumping unit and the downhole sucker rod string.

[0003] In the prior art, CN214464039U discloses a sealing structure for the polished rod of a pumping unit. This sealing structure involves first aligning the sealing ring 1 inside sealing shell 1 and sealing shell 2 with the sealing ring 2 on the outer periphery of the polished rod body. Then, locking ring 1 and locking ring 2 are fitted onto the outer periphery of locking shell 1 and locking shell 2. Bolts and nuts are tightened to fix locking ring 1 and locking ring 2. The grease injection cap is then opened to inject grease into the grease injection cavity, reducing the friction between the polished rod body and sealing shell 1 and sealing shell 2. When the polished rod body rubs against the sealing mechanism, sealing ring 1 and sealing ring 2 pull and press against each other, thus ensuring the sealing of the grease injection cavity. However, in the sealed state, the grease injection cavity can only communicate with the outside through the grease injection hole. When the grease injection hole is used for grease injection, the air inside the grease injection cavity cannot be expelled. Therefore, this invention proposes a sealing structure for the polished rod of a pumping unit. Utility Model Content

[0004] In view of the technical problems existing in the prior art, this utility model provides a polished rod sealing structure for oil pumping units.

[0005] The technical solution adopted by this utility model is: a smooth rod sealing structure for an oil pump, including a sealing shell, a pressure cap coaxially distributed at the top of the sealing shell, a pressure tube coaxially distributed fixedly connected to the inner top surface of the pressure cap, a cylindrical sealing packing coaxially distributed fixedly bonded to the inner side wall of the pressure tube, an exhaust pipe and a grease injection pipe fixedly installed on the outer top surface of the pressure cap, both the exhaust pipe and the grease injection pipe being connected to the inner cavity of the pressure cap, a horizontally distributed feed hole and a discharge hole opened on the outer side wall of the pressure tube, the discharge hole being higher in the vertical direction than the feed hole, a conical sealing packing coaxially distributed inside the sealing shell, and a smooth rod body coaxially distributed vertically arranged inside the sealing shell.

[0006] A further feature of this invention is that one end of the light rod body vertically penetrates the outer top surface of the pressure cap and extends inward, while the other end of the light rod body vertically penetrates the outer bottom surface of the sealing housing and extends outward.

[0007] A further feature of this invention is that the inner wall of the sealing housing has several interconnected grease grooves, the inner wall of the sealing housing is conical, the taper ratio of the inner wall of the sealing housing to the outer wall of the conical sealing packing is equal, and the conical sealing packing abuts against the inner wall of the sealing housing.

[0008] A further feature of this invention is that the outer surface of the sealing housing is machined with an external thread near the top, and the inner surface of the pressure cap is machined with an internal thread near the bottom, and the sealing housing and the pressure cap are threadedly connected.

[0009] A further feature of this invention is that, during the threaded engagement of the sealing housing and the pressure cap, the end of the pressure tube abuts against the outer top surface of the tapered sealing packing.

[0010] A further feature of this invention is that the top end of the cylindrical sealing packing extends to the inner top surface of the pressure cap, and the vertical height of the end of the cylindrical sealing packing is higher than the position of the discharge hole.

[0011] The present invention is further configured such that the light rod body slides through the pressure cap, the cylindrical sealing packing, the conical sealing packing (9) and the outer bottom surface of the sealing shell, and a dustproof sleeve coaxially sleeved on the outside of the light rod body is fixedly connected to the outer top surface of the pressure cap and the outer bottom surface of the sealing shell.

[0012] A further feature of this invention is that a lifting ring is fixedly installed on the outer top surface of the conical sealing packing, and the lifting ring is used to lift the conical sealing packing out of the sealing housing.

[0013] The beneficial effects of this utility model are:

[0014] In this invention, by fixing and connecting the exhaust pipe and the grease injection pipe on the outer top surface of the pressure cap, when grease needs to be injected into the sealing housing, the air remaining in the sealing housing can be discharged in time through the exhaust pipe, thereby effectively avoiding interference with the smooth injection of grease due to air pressure obstruction in the housing, and ensuring the smoothness and reliability of the grease injection operation.

[0015] In this utility model, dustproof sleeves coaxially sleeved around the outer periphery of the optical rod body are fixedly mounted on both the outer top surface of the pressure cap and the outer bottom surface of the sealing shell. This effectively prevents dust and other external impurities from intruding, thereby avoiding contamination or wear of the optical rod body and the core components inside the sealing shell by impurities. From a structural perspective, this provides a reliable guarantee for the operational stability and service life of the overall device. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the polished rod sealing structure of the oil pumping unit of this utility model;

[0017] Figure 2In the polished rod sealing structure of the oil pumping unit of this utility model Figure 1 A schematic diagram of the front section structure;

[0018] Figure 3 yes Figure 2 Enlarged structural diagram of region A in the middle;

[0019] Figure 4 yes Figure 2 A magnified structural diagram of region B in the middle.

[0020] The diagram is marked as follows:

[0021] 1. Sealing shell; 2. Pressure cap; 3. Polished rod body; 4. Exhaust pipe; 5. Grease injection pipe; 6. Dust cover; 7. Pressure pipe; 8. Cylindrical sealing packing; 9. Conical sealing packing; 10. Grease inlet groove; 11. Lifting ring; 12. Discharge hole; 13. Feed hole. Detailed Implementation

[0022] In the description of this utility model, it should be noted that the terms "front", "up", "down", "left", "right", "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this utility model.

[0023] The following is in conjunction with the appendix Figure 1-4 The present invention will be further described below.

[0024] To address the problems existing in the background art, this application proposes the following technical solution: a rod sealing structure for a pumping unit, comprising a sealing housing 1, with coaxially distributed pressure caps 2 covering the top of the sealing housing 1. External threads are machined on the outer surface of the sealing housing 1 near the top, and internal threads are machined on the inner surface of the pressure caps 2 near the bottom. The sealing housing 1 and the pressure caps 2 are threadedly connected. During the thread engagement process, the end of the pressure tube 7 abuts against the outer top surface of the conical sealing packing 9. Coaxially distributed pressure tubes 7 are fixedly connected to the inner top surface of the pressure caps 2, and coaxially distributed cylindrical seals are fixedly bonded to the inner wall of the pressure tubes 7. The packing 8 and the pressure cap 2 are fixedly installed with an exhaust pipe 4 and a grease injection pipe 5. The exhaust pipe 4 and the grease injection pipe 5 are connected to the inner cavity of the pressure cap 2. The outer wall of the pressure pipe 7 is provided with horizontally distributed feed holes 13 and discharge holes 12. The height of the discharge hole 12 in the vertical direction is higher than that of the feed hole 13 in the vertical direction. The top of the cylindrical sealing packing 8 extends to the inner top surface of the pressure cap 2. The height of the end of the cylindrical sealing packing 8 in the vertical direction is higher than that of the discharge hole 12. The sealing housing 1 is provided with coaxially distributed conical sealing packing 9. The sealing housing 1 is provided with coaxially distributed smooth rod body 3 in the vertical direction.

[0025] During the actual operation, when preparing for sealing, first adjust the position of the pressure tube 7 by screwing the sealing housing 1 and the pressure cap 2 together. A handle for driving the pressure cap 2 to rotate can be fixedly installed on the outer surface of the pressure cap 2 for easy operation. Stop rotating the pressure cap 2 before reaching the "limit position". At this time, the pressure tube 7 is in contact with the outer top surface of the conical sealing packing 9 but not in tight contact. Then open the vent pipe 4 and the grease injection pipe 5, and inject the grease into the sealing housing 1 through the grease injection pipe 5. The grease is guided by its own fluidity and the structure of the pressure tube 7, first entering the interior of the pressure tube 7 through the lower feed hole 13 on the outer wall of the pressure tube 7, and then gradually filling the interior through the higher discharge hole 12. The air inside the pressure tube 7 is discharged through the exhaust pipe 4 to prevent air stagnation from affecting the grease filling effect. After the sealing housing 1 is filled with grease (judged by the overflow of grease from the exhaust pipe 4), the exhaust pipe 4 and the grease injection pipe 5 are closed. The pressure cap 2 is then screwed to the "limit position" so that the end of the pressure tube 7 is in close contact with the outer top surface of the conical sealing packing 9. At this time, the cylindrical sealing packing 8, because its top end is connected to the inner top surface of the pressure cap 2 and its end is higher than the discharge hole 12, can effectively prevent the grease in the pressure tube 7 from rising, forming the first sealing line. At the same time, the pressure of the pressure tube 7 is transmitted to the conical sealing packing 9, laying the foundation for the subsequent radial sealing rod body 3. The beneficial effects are that the threaded connection method can precisely control the pressure of the pressure tube 7 on the conical sealing packing 9, avoiding damage to the packing due to excessive pressure or failure of the seal due to insufficient pressure; the height difference design between the inlet hole 13 and the outlet hole 12 ensures that the grease in the pressure tube 7 is fully filled without dead corners; the cooperation between the exhaust pipe 4 and the grease injection pipe 5 realizes efficient injection of grease, reduces air residue in the sealing structure, and the cylindrical sealing packing 8 and the subsequent conical sealing packing 9 form a double sealing trend, improving the initial reliability of the overall seal.

[0026] In this embodiment, one end of the light rod body 3 vertically penetrates the outer top surface of the pressure cap 2 and extends inward, and the other end of the light rod body 3 vertically penetrates the outer bottom surface of the sealing housing 1 and extends outward. The light rod body 3 slides through the pressure cap 2, the cylindrical sealing packing 8, the conical sealing packing (9) and the outer bottom surface of the sealing housing 1. A dust cover 6 coaxially sleeved on the outside of the light rod body 3 is fixedly connected to both the outer top surface of the pressure cap 2 and the outer bottom surface of the sealing housing 1.

[0027] During operation, the polished rod body 3 slides up and down with the pumping unit to achieve oil pumping. Its design, which penetrates the pressure cap 2, cylindrical sealing packing 8, conical sealing packing 9, and the bottom surface of the sealing housing 1, ensures that it remains in the center of the sealing structure during sliding, preventing seal failure due to misalignment. When the polished rod body 3 slides up and down, it drives the grease between the conical sealing packing 9 and the polished rod body 3, and between the cylindrical sealing packing 8 and the polished rod body 3, to continuously fill the tiny gaps between them. This reduces dry friction between the polished rod body 3 and the packing and further enhances the sealing effect by utilizing the viscosity of the grease. At the same time, the dust sleeves 6 on the outer top surface of the pressure cap 2 and the outer bottom surface of the sealing housing 1 extend and retract synchronously with the sliding of the polished rod body 3, effectively preventing external dust, sand, rainwater, and other impurities from adhering to the surface of the polished rod body 3 or entering the interior of the sealing structure. The beneficial effects are that the through-type design of the polished rod body 3 meets the operational requirements of the pumping unit and ensures stable power transmission; the grease filling method that slides with the polished rod achieves continuous lubrication and seal reinforcement during the dynamic sealing process, reduces the wear rate of the polished rod and packing, and extends the service life of the components; the dust cover 6 prevents impurities from damaging the sealing surface, reduces the frequency of sealing failures, reduces maintenance costs, and at the same time ensures smooth sliding of the polished rod body 3, reducing the energy consumption of the pumping unit.

[0028] In this embodiment, a plurality of interconnected grease grooves 10 are provided on the inner sidewall of the sealing housing 1. The inner sidewall of the sealing housing 1 is conical. The taper ratio between the inner sidewall of the sealing housing 1 and the outer sidewall of the conical sealing packing 9 is equal. The conical sealing packing 9 abuts against the inner sidewall of the sealing housing 1. A lifting ring 11 is fixedly installed on the outer top surface of the conical sealing packing 9. The lifting ring 11 is used to lift the conical sealing packing 9 out of the sealing housing 1.

[0029] During the specific operation, in the grease injection stage, the grease entering the sealing housing 1 from the grease injection pipe 5 will be guided by several interconnected grease inlets 10 to flow quickly and evenly to the gap between the conical sealing packing 9 and the inner wall of the sealing housing 1. This prevents grease from accumulating locally and ensures that the gap is completely filled with grease, providing a sufficient lubrication basis for subsequent sealing. Since the taper ratio between the inner wall of the sealing housing 1 and the outer wall of the conical sealing packing 9 is equal, when the pressure pipe 7 applies axial pressure to the conical sealing packing 9, the conical sealing packing 9 can deform evenly along the inner wall of the sealing housing 1, applying a uniform radial sealing force to the smooth rod body 3. This avoids leakage due to insufficient local pressure caused by taper mismatch, or damage to the packing due to excessive local pressure. When it is necessary to replace the conical sealing packing 9, it is not necessary to disassemble the entire sealing housing 1. The conical sealing packing 9 can be removed from the sealing housing 1 simply by hooking the lifting ring 11 with a tool, simplifying the disassembly and assembly process. The beneficial effects are that the grease groove 10 improves the grease distribution efficiency, ensures uniform lubrication of the sealing surface, and reduces local friction and overheating; the design of equal taper ratios ensures uniform distribution of sealing force, significantly improves sealing reliability, and reduces leakage risk; the setting of the lifting ring 11 simplifies the replacement operation of the conical sealing packing 9, shortens maintenance time, improves equipment maintenance efficiency, and avoids damage to the sealing housing 1 or the smooth rod body 3 during disassembly and assembly.

[0030] To ensure that those skilled in the art fully understand the technical solution, the usage method of this embodiment is as follows: When the pressure cap 2 and the sealing housing 1 are connected by threads to the "limit position", the end of the pressure tube 7 will be in close contact with the outer top surface of the conical sealing packing 9. Since the outer side wall of the conical sealing packing 9 and the inner side wall of the sealing housing 1 have the same shape, when the pressure tube 7 applies pressure to the conical sealing packing 9, the conical sealing packing 9 will apply a radial force to the smooth rod body 3 located inside the conical sealing packing 9 under the force of the inner side wall of the sealing housing 1. Before the threaded connection between the pressure cap 2 and the sealing housing 1 reaches the "limit position", the rotation of the pressure cap 2 is stopped. At this time, the pressure tube 7 is already in contact with the outer top surface of the conical sealing packing 9, but not tightly. When the seal is filled with grease, the exhaust pipe 4 and the grease injection pipe 5 are opened. At this time, the grease is injected into the sealing housing 1 through the grease injection pipe 5. The grease will flow into the gap between the conical sealing packing 9 and the sealing housing 1 under the guidance of the grease inlet groove 10. When the grease overflows the outer top surface of the conical sealing packing 9, it will enter the pressure tube 7 through the feed hole 13. Under the action of the discharge hole 12, the grease will fill the pressure tube 7. After the sealing housing 1 is filled with grease, the exhaust pipe 4 and the grease injection pipe 5 are closed. The pressure cap 2 is rotated to make the end of the pressure tube 7 and the outer top surface of the conical sealing packing 9 come into close contact. The smooth rod body 3 is slid up and down, which will drive the grease into the gap between the conical sealing packing 9, the cylindrical sealing packing 8 and the smooth rod body 3.

[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0032] Although embodiments of the present invention have been shown and described, the scope of the present invention will be defined by the appended claims and their equivalents for those skilled in the art.

Claims

1. A polished rod sealing structure for a pumping unit, comprising a sealing housing (1), characterized in that, The top of the sealing housing (1) is covered with a pressure cap (2) distributed coaxially. A pressure tube (7) is fixedly connected to the inner top surface of the pressure cap (2). A cylindrical sealing packing (8) is fixedly bonded to the inner side wall of the pressure tube (7). An exhaust pipe (4) and a grease injection pipe (5) are fixedly installed on the outer top surface of the pressure cap (2). The exhaust pipe (4) and the grease injection pipe (5) are both connected to the inner cavity of the pressure cap (2). A feed hole (13) and a discharge hole (12) are opened on the outer side wall of the pressure tube (7). The height of the discharge hole (12) in the vertical direction is higher than that of the feed hole (13) in the vertical direction. A conical sealing packing (9) is provided in the sealing housing (1). A smooth rod body (3) is vertically provided in the sealing housing (1).

2. The polished rod sealing structure of the pumping unit according to claim 1, characterized in that, One end of the light rod body (3) penetrates vertically through the outer top surface of the pressure cap (2) and extends inward, while the other end of the light rod body (3) penetrates vertically through the outer bottom surface of the sealing shell (1) and extends outward.

3. The polished rod sealing structure of the pumping unit according to claim 1, characterized in that, The inner wall of the sealing housing (1) is provided with several interconnected grease grooves (10). The inner wall of the sealing housing (1) is conical. The taper ratio between the inner wall of the sealing housing (1) and the outer wall of the conical sealing packing (9) is equal. The conical sealing packing (9) abuts against the inner wall of the sealing housing (1).

4. The polished rod sealing structure of the pumping unit according to claim 1, characterized in that, The outer surface of the sealing housing (1) is machined with external threads near the top, and the inner surface of the pressure cap (2) is machined with internal threads near the bottom. The sealing housing (1) and the pressure cap (2) are threaded together.

5. The polished rod sealing structure of the pumping unit according to claim 4, characterized in that, During the threaded engagement of the sealing housing (1) and the pressure cap (2), the end of the pressure tube (7) abuts against the outer top surface of the conical sealing packing (9).

6. The polished rod sealing structure of the pumping unit according to claim 1, characterized in that, The top end of the cylindrical sealing packing (8) extends to the inner top surface of the pressure cap (2), and the end of the cylindrical sealing packing (8) is higher in the vertical direction than the location of the discharge hole (12).

7. The polished rod sealing structure of the pumping unit according to claim 1, characterized in that, The light rod body (3) slides through the pressure cap (2), cylindrical sealing packing (8), conical sealing packing (9) and the outer bottom surface of the sealing shell (1). A dust cover (6) is fixedly connected to the outer top surface of the pressure cap (2) and the outer bottom surface of the sealing shell (1) and is coaxially sleeved on the outside of the light rod body (3).

8. The polished rod sealing structure of the pumping unit according to claim 1, characterized in that, A lifting ring (11) is fixedly installed on the outer top surface of the conical sealing packing (9). The lifting ring (11) is used to lift the conical sealing packing (9) out of the sealing housing (1).

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