Airtight reciprocating shaft mechanical seal for pumping unit wellhead

Abstract

The invention relates to the technical field of mechanical seals, in particular to an airtight reciprocating shaft mechanical seal for a pumping unit wellhead. The device comprises a flow choking ring, a flow guide ring, a polished rod and a sealing box, the flow blocking ring and the flow guide ring are both annular rubber structural bodies, polish rod holes corresponding to polish rods are formed in the inner circles of the flow blocking ring and the flow guide ring, a plurality of protruding rubber columns and positioning grooves are arranged at the upper ends and the lower ends of the outer circles of the flow blocking ring and the flow guide ring, and flow guide plates are arranged on the surfaces of the flow blocking ring and the flow guide ring. A flow stopping umbrella structural body is mounted at the closing-up position of the circle center of the flow stopping ring of the flow stopping ring flow guide plate, and the front end of the flow stopping ring flow guide plate is in a smooth transition conical tip shape; and the flow blocking ring and the flow guide ring are positioned, combined and mounted in the sealing box through the plurality of convex rubber columns and the positioning grooves. Traditional packing sealing is changed into semi-contact-non-contact one-way breathing type packing sealing, gas is controlled to serve as an intermediary, the speed between packing and a polish rod is repeatedly switched from normal to slow, medium leakage is avoided, and the service cycle of the packing is greatly prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical seals, and in particular to an airtight reciprocating shaft mechanical seal for a wellhead of an oil pump. Background Art

[0002] At present, the pumping unit in the oil industry is a rod oil production machine, which uses the motor to rotate to drive the beam mechanism based on the principle of lever. The pumping rod is connected to the wellhead vertically to the oil pump in the well, and reciprocates to lift the medium at the bottom of the well step by step to the ground to complete the oil production process. A sealing treatment is required at the joint between the wellhead and the pumping rod to prevent the medium from directly overflowing the ground and causing pollution. The pumping rod is replaced with a light shaft, which can also be called a light rod. A packing sealing device is added to the wellhead, and the sealing packing is filled to construct a packing seal. This part of the reciprocating lifting process belongs to a low-speed and long-stroke axial seal. Since the friction between the packing and the light rod will cause the loss of the packing, in order to achieve the continuity of the seal, continuous external power is required to maintain the process of pressurizing the packing. Frequent packing has become the main work of front-line employees in oil production.

[0003] The existing packing seals of pumping units have the following problems: the packing material has poor elasticity, excessive wear and tear, and too fast wear and tear, so the radial deformation of the packing is very limited, and the sealing effect is poor; the medium has low oil content, which leads to poor lubrication ability of the packing to a certain extent, and the friction with the light rod increases, resulting in serious loss; the packing is too hard or mixed with particles and impurities, and long-term operation causes wear of the light rod, which in turn causes increased packing loss; damage to the surface of the light rod and scratches on the surface cause increased wear and loss of the packing; the medium pressure in the wellhead is too high or the pressure changes greatly, and the packing of the sealing box is damaged, causing medium leakage; in the process of adding packing, in order to avoid medium leakage, the packing is filled very full and tight, which actually increases the travel resistance of the light rod, which in turn increases the energy consumption of the pumping unit motor. At the same time, the packing is overheated and worn, and its life is shortened. Summary of the invention

[0004] 1. Technical issues to be resolved: The invention provides an airtight reciprocating shaft mechanical seal for a wellhead of an oil pump, which solves the problems in the prior art of adding a packing sealing device and filling a sealing filler, resulting in serious packing loss and poor sealing effect due to friction between the packing and the polished rod.

[0005] (II) Technical solution: In order to solve the above technical problems, the present invention provides an airtight reciprocating shaft mechanical seal for a wellhead of an oil pump, comprising: A baffle ring, a guide ring, a polished rod and a sealing box, wherein the center of the sealing box passes through the polished rod, a plurality of baffle rings and a plurality of guide rings are installed inside the sealing box, the baffle rings and the guide rings are combined in pairs, and the number of the baffle rings is adapted to the number of the guide rings; The baffle ring and the guide ring are both annular rubber structures, the light rod passes through multiple baffle rings and multiple guide rings, the outer circles of the baffle ring and the guide ring are both trapezoidal structures with different diameters on both sides, the upper and lower ends of the baffle ring trapezoidal structure are respectively provided with multiple baffle ring raised rubber columns and multiple baffle ring positioning grooves, the conical surface of the baffle ring trapezoidal structure is provided with a baffle ring guide plate, the baffle ring guide plate is installed with a baffle umbrella structure at the center of the baffle ring, the upper and lower ends of the guide ring trapezoidal structure are respectively provided with multiple guide ring raised rubber columns and multiple guide ring positioning grooves, the conical surface of the guide ring trapezoidal structure is provided with a guide ring guide plate, and the front end of the guide ring guide plate is a smoothly transitioned cone tip.

[0006] Preferably, a reinforcing plate is installed between the baffle ring and the guide ring, the reinforcing plate is a circular ring structure, and the polished rod passes through the reinforcing plate.

[0007] Preferably, the inner circle of the reinforcing plate is provided with a reinforcing plate polished rod hole corresponding to the polished rod, and the outer circle of the reinforcing plate is provided with a plurality of positioning holes and glue column grooves.

[0008] Preferably, the protruding rubber column of the baffle ring above the baffle ring passes through the positioning hole rubber column groove of the reinforcing plate and is inserted into the guide ring positioning groove of the guide ring.

[0009] Preferably, the number of the positioning hole rubber column grooves is adapted to the number of the convex rubber columns of the baffle ring.

[0010] Preferably, the spoiler ring guide plate is provided with a plurality of regular spoiler ring cutting lines at the center axis point of the spoiler ring, and the guide ring guide plate is provided with a plurality of regular guide ring cutting lines at the center axis point of the guide ring.

[0011] Preferably, the baffle ring is divided into a plurality of equal baffle ring pieces by a plurality of baffle ring cutting lines, and the baffle ring raised rubber columns and baffle ring positioning grooves are staggeredly installed on different baffle ring pieces; the guide ring is divided into a plurality of equal guide ring pieces by a plurality of guide ring cutting lines, and the guide ring raised rubber columns and guide ring positioning grooves are staggeredly installed on different guide ring pieces.

[0012] Preferably, the number of the raised rubber columns of the blocker ring is adapted to the number of the positioning grooves of the blocker ring, and the number of the raised rubber columns of the guide ring is adapted to the number of the positioning grooves of the guide ring.

[0013] Preferably, the number of the raised rubber columns of the blocker ring is adapted to the number of the raised rubber columns of the guide ring, and the number of the positioning grooves of the blocker ring is adapted to the number of the positioning grooves of the guide ring.

[0014] Preferably, the inner circle of the baffle ring is provided with a baffle ring polished rod hole corresponding to the polished rod; the inner circle of the guide ring is provided with a guide ring polished rod hole corresponding to the polished rod.

[0015] (III) Beneficial effects: The present invention provides an airtight reciprocating shaft mechanical seal for a wellhead of an oil pump. By changing the traditional packing seal into a semi-contact-non-contact one-way breathing packing seal, the gas is controlled as a medium to repeatedly switch between the packing and the light rod from normal speed to slow speed, thereby delaying the follow-up of subsequent media, avoiding medium leakage, and greatly extending the service life of the packing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of an airtight reciprocating shaft mechanical seal for a wellhead of an oil pumping unit according to an embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of the baffle ring of the present invention; Figure 3 It is a cross-sectional view of the flow-blocking ring of the present invention; Figure 4 This is a schematic diagram of the guide ring structure of the present invention; Figure 5 It is a cross-sectional view of the guide ring of the present invention; Figure 6 This is a schematic diagram of the basic sealing unit structure of the present invention; Figure 7 A three-dimensional view of the basic sealing unit of the present invention; Figure 8 It is a half-section structural diagram of the basic sealing unit of the present invention; Fig. 9 It is a schematic diagram of the morphology of the spoiler umbrella structure of the present invention.

[0017] Among them, 1-blocking ring; 2-guide ring; 3-reinforcement plate; 4-light rod; 5-blocking ring light rod hole; 6-blocking ring guide plate; 7-blocking umbrella structure; 8-blocking ring raised rubber column; 9-blocking ring positioning groove; 10-blocking ring cutting line; 11-guide ring light rod hole; 12-guide ring guide plate; 13-guide ring raised rubber column; 14-guide ring positioning groove; 15-guide ring cutting line; 16-reinforcement plate light rod hole; 17-positioning hole rubber column groove; 18-sealing box; 71-water drop-shaped spoiler structure; 72-crescent-shaped spoiler structure; 73-arc-shaped spoiler structure. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by "left", "right", "up", "down", "inside" and "outside" are all based on the directions or positional relationships shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description. It does not indicate or imply that the referred parts must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0020] like Figure 1 As shown, it is a schematic diagram of the structure of an airtight reciprocating shaft mechanical seal for a wellhead of an oil pumping unit according to an embodiment of the present invention, comprising a baffle ring 1, a guide ring 2, a polished rod 4 and a sealing box 18, the center of the sealing box 18 passes through the polished rod 4, a plurality of baffle rings 1 and a plurality of guide rings 2 are installed inside the sealing box 18, the baffle rings 1 and the guide rings 2 are combined in pairs, and the number of the baffle rings 1 is adapted to the number of the guide rings 2.

[0021] like Figure 2 and Figure 3 As shown, the spoiler ring 1 is an annular rubber structure, the inner circle of the spoiler ring 1 is provided with a spoiler ring smooth rod hole 5 corresponding to the smooth rod 4, and the outer circle of the spoiler ring 1 is a trapezoidal structure with different diameters on both sides; a spoiler ring guide plate 6 is provided on the conical surface of the spoiler ring 1 trapezoidal structure, and a spoiler umbrella structure 7 is installed at the center of the spoiler ring 1. A plurality of spoiler ring protruding rubber columns 8 and a plurality of spoiler ring positioning grooves 9 are respectively provided at the upper and lower ends of the spoiler ring 1 trapezoidal structure.

[0022] like Figure 4 and Figure 5 As shown, the guide ring 2 is an annular rubber structure, the inner circle of the guide ring 2 is provided with a guide ring polished rod hole 11 corresponding to the polished rod 4, and the outer circle of the guide ring 2 is a trapezoidal structure with different diameters on both sides; a guide ring guide plate 12 is provided on the conical surface of the guide ring 2 trapezoidal structure, and the front end of the guide ring guide plate 12 is a cone tip with a smooth transition; a plurality of guide ring raised rubber columns 13 and a plurality of guide ring positioning grooves 14 are respectively provided at the upper and lower ends of the guide ring 2 trapezoidal structure.

[0023] In actual applications, the baffle ring 1 is positioned by multiple baffle ring raised rubber columns 8 and baffle ring positioning grooves 9, and the guide ring 2 is positioned by multiple guide ring raised rubber columns 13 and guide ring positioning grooves 14. The baffle ring 1 and the guide ring 2 are paired through a positioning combination, and multiple pairs of baffle rings 1 and guide rings 2 are installed together inside the sealing box 18. It should be noted that since the baffle ring 1 and the guide ring 2 are combined in pairs, the number of baffle rings 1 is adapted to the number of guide rings 2, so the number of baffle ring raised rubber columns 8 is adapted to the number of guide ring raised rubber columns 13, and the number of baffle ring positioning grooves 9 is adapted to the number of guide ring positioning grooves 14.

[0024] In the present mechanical seal, the number of the blocker ring raised rubber columns 8 is adapted to the number of the blocker ring positioning grooves 9, the number of the guide ring raised rubber columns 13 is adapted to the number of the guide ring positioning grooves 14, and in addition, an annulus is provided in the middle of the blocker ring 1 and the guide ring 2, and the light rod 4 is centrally inserted into the annulus.

[0025] like Figures 6 to 8 As shown, in order to improve the pressure bearing capacity, in this embodiment, a reinforcing plate 3 is installed between the baffle ring 1 and the guide ring 2, and the reinforcing plate 3 is a circular ring structure; the inner circle of the reinforcing plate 3 is provided with a reinforcing plate polished rod hole 16 corresponding to the polished rod 4, and the outer circle of the reinforcing plate 3 is provided with a plurality of positioning hole glue column grooves 17.

[0026] In practical applications, the blocker ring protruding rubber column 8 above the blocker ring 1 passes through the positioning hole rubber column groove 17 of the reinforcing plate 3 and is inserted into the guide ring positioning groove 14 of the guide ring 2 to complete the basic sealing unit assembly.

[0027] Therefore, the positioning hole glue column groove 17 of the reinforcing plate 3 not only needs to match the raised glue column 8 of the baffle ring above the baffle ring 1, but also needs to cooperate with the guide ring positioning groove 14 of the guide ring 2. That is to say, the number of positioning hole glue column grooves 17 is consistent with the number of raised glue columns 8 of the baffle ring, and the number of raised glue columns 8 of the baffle ring is consistent with the number of guide ring positioning grooves 14.

[0028] It should be noted that the baffle ring 1 and the guide ring 2 can be assembled and installed multiple times to form a sealing packing assembly, wherein the number of reinforcing plates 3 can be selected based on conditions such as pressure to determine whether to add them and the number of reinforcing plates 3 to add.

[0029] In addition, it should be noted that if Fig. 9 As shown, the spoiler umbrella structure 7 includes a teardrop-shaped spoiler structure 71, a crescent-shaped spoiler structure 72 and an arc-shaped spoiler structure 73, but is not limited to the above three similar functional states of changing the direction of the fluid. Its purpose is to achieve the steering function of the passing airflow by establishing an arc-shaped umbrella-shaped structural surface; in actual application, when the light rod 4 is centered, the spoiler umbrella structure 7 is close to the light rod 4, but does not contact it.

[0030] In the present mechanical seal, a plurality of regular baffle ring cutting lines 10 are provided on the baffle ring 1 center axis point of the baffle ring guide plate 6, so that the baffle ring guide plate 6 can move up and down in segments; a plurality of regular baffle ring cutting lines 15 are provided on the baffle ring 2 center axis point of the guide ring guide plate 12, so that the guide ring guide plate 12 can move up and down in segments.

[0031] Generally speaking, in order to enable the spoiler ring 1 and the guide ring 2 to be installed in coordination, the number of spoiler ring cutting lines 10 is adapted to the number of guide ring cutting lines 15. In practical applications, the spoiler ring 1 and the guide ring 2 can be preset in an eight-part structure so that their respective raised rubber columns and their respective positioning grooves form an angle of 360° / 8=45° on both sides, which is used for staggered installation of the spoiler ring piece and the guide ring piece.

[0032] However, it should be noted that the cutting line 10 of the baffle ring and the cutting line 15 of the guide ring shall not overlap; the cutting of the guide plate can be completed in advance, or it can be cut on site according to the reserved mark on the surface of the filler body; the cutting depth of the guide plate depends on the pressure of the sealing box, more cutting is done when the pressure is low, and less cutting is done when the pressure is high.

[0033] In actual application, there is a breathing effect when the polished rod 4 reciprocates up and down through the sealing box; when the polished rod goes up, the mixed gas in the wellbore at the bottom of the sealing box is brought upward by the polished rod 4 and passes through the gap between the polished rod and the filler; when the polished rod goes down, the wellbore at the bottom of the sealing box presents a short-term negative pressure state, and the air outside the sealing box moves into the sealing box and passes through the gap between the polished rod and the filler.

[0034] The following is a detailed description of the working principle of this airtight reciprocating shaft mechanical seal for the wellhead of the pumping unit: In this embodiment, the spoiler ring 1 and the guide ring 2 can be preset in an eight-part structure so that their respective raised rubber columns and their respective positioning grooves form an angle of 360° / 8=45° on both sides, which is used for staggered installation of the spoiler ring and the guide ring.

[0035] In practical applications, firstly, an opening cut is made at any position of the edge of the guide ring 2, and it overlaps with the guide ring cutting line 15 on the guide ring guide plate 12; secondly, an opening cut is made at the edge position of the blocker ring 1, and it overlaps with the blocker ring cutting line 10 on the blocker ring guide plate 6; but the cutting positions of the blocker ring 1 and the guide ring 2 shall not overlap, and both are inserted into the light rod through the opening.

[0036] It should be noted that the cutting of the guide plate can be completed in advance or can be cut on site according to the reserved marks on the surface of the packing body; the cutting depth of the guide plate depends on the pressure bearing condition of the packing box, more cutting is required when the pressure is low and less cutting is required when the pressure is high.

[0037] When installing the basic sealing unit, the baffle ring 1 and the guide ring 2 are positioned and assembled by means of a plurality of raised rubber columns and positioning grooves, so that the baffle ring 1 and the guide ring 2 are staggered and matched and docked to form a combined monomer, and grease is added to the gap in the assembly to improve creep.

[0038] In actual application, the device can continue to add combined monomers according to the depth and continue to connect until the assembly is filled, lower the sealing box pressure cover and slowly compress the packing assembly, but do not over-compress it, start the oil pump and run it, check whether there is leakage in the sealing box, observe whether the gas breathing cycle at the sealing box pressure cover is normal, and whether there is continuous leakage of liquid medium, then the equipment can enter the normal operation state.

[0039] It should be noted that if the wellhead pressure is high and leakage occurs as soon as the filler is installed, a reinforcing plate 3 should be superimposed on the bottom filler assembly in the sealing box. The number of reinforcing plates 3 to be added can be determined as appropriate based on the pressure conditions. In principle, a reinforcing plate 3 can be added to each set of combined seals.

[0040] When the polished rod 4 moves downward, the dynamic liquid level in the wellbore drops accordingly, and the wellbore side between the dynamic liquid level and the sealing box presents a negative pressure state. The gas outside the sealing box is sucked into the wellbore through the gap between the filler in the sealing box and the polished rod 4. The guide ring 2 is deformed and compressed downward, causing the flow blocking ring 1 to be compressed and deformed inward, the gas suction space is expanded, and a large amount of gas enters the wellbore.

[0041] When the light rod 4 goes up, the dynamic liquid level in the wellbore rises with the upward movement of the light rod 4, pushing the gas at the top of the produced liquid into the sealing box and exhaling to the outside. At this time, the flow-blocking ring 1 is deformed outward by the gas pressure, but the spoiler umbrella structure 7 at its front end is supported by the rear reinforcing plate 3 or the guide plate 2, forming a spoiler effect that changes the path of the outward gas, reverses the airflow direction to the lateral end, thereby forming an obstacle to the outward airflow, reducing its flow rate and the amount of fluid passing through. This is the Tesla valve effect.

[0042] Under the action of the Tesla valve effect, the overflowing fluid is restricted and slowed down, blocking the passage of subsequent produced medium, and the produced medium enters the process normally. When the gas blockage is about to reach its limit, the subsequent produced liquid medium will also overflow the sealing box, the upward lifting of the pumping unit ends, the bare rod 4 starts to descend, and the breathing effect of the packing is changed to suction, and the operation is repeated.

[0043] It should be noted that, although the light rod 4 and the filler assembly do not contact each other in principle, under the impact of gas, the rubber material of the filler will also be worn to a certain extent after long-term operation, especially the spoiler umbrella structure 7 on the spoiler ring 1 will be worn, which will weaken the Tesla effect. The device can extend the spoiler umbrella structure 7 inward by continuously increasing the filler assembly, continue the Tesla effect, and thus extend the service life of the filler.

[0044] The present invention provides a hermetic reciprocating shaft mechanical seal for a wellhead of a pumping unit. The sealing assembly formed by the flow blocking ring 1 and the flow guide ring 2 can implement unidirectional restriction on the airflow passing through the gap between the packing and the rod, thereby utilizing the hysteresis of the gas to block the leakage of the produced medium. According to the simulation calculation of the fluid model, the resistance of a single sealing assembly to the airflow under an ideal state can exceed 10-30%. By recombining multiple groups of sealing assemblies, the airflow velocity passing through the gap between the packing and the rod will be greatly reduced, and the pressure in the wellbore below the packing box will increase, which will in turn cause a decrease in the liquid production and an increase in energy consumption. Therefore, the number of sealing assemblies needs to be controlled as appropriate. For example, an incompressible filler is added to the bottom of the existing packing box stuffing box to reduce the space capacity of the stuffing box.

[0045] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An airtight reciprocating shaft mechanical seal for a wellhead of an oil pump, characterized in that: include: A baffle ring (1), a guide ring (2), a polished rod (4) and a sealing box (18), wherein the center of the sealing box (18) passes through the polished rod (4), a plurality of baffle rings (1) and a plurality of guide rings (2) are installed inside the sealing box (18), the baffle rings (1) and the guide rings (2) are combined in pairs, and the number of the baffle rings (1) matches the number of the guide rings (2); The baffle ring (1) and the guide ring (2) are both annular rubber structures; the light rod (4) passes through a plurality of baffle rings (1) and a plurality of guide rings (2); the outer circles of the baffle ring (1) and the guide ring (2) are both trapezoidal structures with different diameters on both sides; a plurality of baffle ring protruding rubber columns (8) and a plurality of baffle ring positioning grooves (9) are respectively provided at the upper and lower ends of the baffle ring (1) trapezoidal structure; a baffle ring guide plate (6) is provided on the conical surface of the baffle ring (1) trapezoidal structure; a baffle umbrella structure (7) is installed on the baffle ring guide plate (6) at the center of the baffle ring (1); a plurality of guide ring protruding rubber columns (13) and a plurality of guide ring positioning grooves (14) are respectively provided at the upper and lower ends of the guide ring (2) trapezoidal structure; a guide ring guide plate (12) is provided on the conical surface of the guide ring (2) trapezoidal structure; and the front end of the guide ring guide plate (12) is in the shape of a smoothly transitioned cone tip.

2. The hermetic reciprocating shaft mechanical seal for a wellhead of an oil pumping unit as claimed in claim 1, characterized in that: A reinforcing plate (3) is installed between the flow-blocking ring (1) and the flow-guiding ring (2); the reinforcing plate (3) is a circular ring structure, and the polished rod (4) passes through the reinforcing plate (3).

3. The hermetic reciprocating shaft mechanical seal for a wellhead of an oil pumping unit as claimed in claim 2, characterized in that: The inner circle of the reinforcing plate (3) is provided with a reinforcing plate polished rod hole (16) corresponding to the polished rod (4), and the outer circle of the reinforcing plate (3) is provided with a plurality of positioning hole glue column grooves (17).

4. The hermetic reciprocating shaft mechanical seal for a wellhead of a pumping unit as claimed in claim 3, characterized in that: The blocker ring protruding rubber column (8) above the blocker ring (1) passes through the positioning hole rubber column groove (17) of the reinforcing plate (3) and is inserted into the guide ring positioning groove (14) of the guide ring (2).

5. The hermetic reciprocating shaft mechanical seal for a wellhead of a pumping unit as claimed in claim 4, characterized in that: The number of the positioning hole rubber column grooves (17) is adapted to the number of the block ring raised rubber columns (8).

6. The hermetic reciprocating shaft mechanical seal for a wellhead of an oil pumping unit as claimed in claim 1, characterized in that: The baffle ring guide plate (6) is provided with a plurality of regular baffle ring cutting lines (10) at the center axis point of the baffle ring (1), and the guide ring guide plate (12) is provided with a plurality of regular guide ring cutting lines (15) at the center axis point of the guide ring (2).

7. The hermetic reciprocating shaft mechanical seal for a wellhead of a pumping unit as claimed in claim 6, characterized in that: The baffle ring (1) is divided into a plurality of equal baffle ring pieces by a plurality of baffle ring cutting lines (10), and the baffle ring raised rubber columns (8) and the baffle ring positioning grooves (9) are staggeredly installed on different baffle ring pieces; the guide ring (2) is divided into a plurality of equal guide ring pieces by a plurality of guide ring cutting lines (15), and the guide ring raised rubber columns (13) and the guide ring positioning grooves (14) are staggeredly installed on different guide ring pieces.

8. The hermetic reciprocating shaft mechanical seal for a wellhead of an oil pumping unit as claimed in claim 1, characterized in that: The number of the blocker ring raised rubber columns (8) is compatible with the number of the blocker ring positioning grooves (9), and the number of the guide ring raised rubber columns (13) is compatible with the number of the guide ring positioning grooves (14).

9. The hermetic reciprocating shaft mechanical seal for a wellhead of an oil pumping unit as claimed in claim 1, characterized in that: The number of the blocker ring raised rubber columns (8) is compatible with the number of the guide ring raised rubber columns (13), and the number of the blocker ring positioning grooves (9) is compatible with the number of the guide ring positioning grooves (14).

10. The hermetic reciprocating shaft mechanical seal for a wellhead of an oil pumping unit as claimed in claim 1, characterized in that: The inner circle of the baffle ring (1) is provided with a baffle ring polished rod hole (5) corresponding to the polished rod (4); and the inner circle of the guide ring (2) is provided with a guide ring polished rod hole (11) corresponding to the polished rod (4).

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