CN215169892U - Positioning structure capable of converting working positions and oil drain device thereof - Google Patents

Abstract

The utility model discloses a positioning structure capable of converting working positions and an oil drainer thereof, wherein the positioning structure is arranged in an interlayer in a sliding way and comprises a body, a cutting pin and a soluble positioning ring which are connected on the body, the body is in friction connection with one side wall of the interlayer, the cutting pin and the soluble positioning ring are both fixedly connected with the other side wall of the interlayer, and the friction force borne by the body is greater than the fixing force of the cutting pin and less than the fixing force of the soluble positioning ring; the utility model discloses set up the frictional force of body between the fixed power of cutting the pin and the fixed power of soluble holding ring, can utilize soluble holding ring to guarantee at a work position, after the soluble holding ring became invalid, utilize to cut the pin and remain stable at this work position, when needs get into another work position, usable frictional force will cut the pin and cut and change to another work position.

Description

Positioning structure capable of converting working positions and oil drain device thereof

Technical Field

The utility model relates to an oil field oil production instrument technical field especially relates to a location structure of convertible work position and bleeder thereof.

Background

The oil inlet valve on the oil well pump is a check valve, so that crude oil on the oil well pump cannot flow back into the well, and the oil inlet valve cannot be lifted out before the operation of lifting the pipe column, so that crude oil exists in the pipe column above the oil well pump when the operation of lifting the pipe column. In order to avoid that the crude oil in the pump flows to the ground when the pipe string is lifted along with the operation, an oil drain device is generally installed on the oil well pump to realize oil drainage and protect the environment of an oil area. An oil drain refers to a tool that drains the crude oil in the tubing above the pump back into the well.

The prior oil drain devices used in oil fields have various forms, such as impact type, baffle type, lifting type, rotating type, supporting type and the like. However, the various oil drains have the defects that:

the principle of the impact type oil drain device is that an impact rod is put into an oil pipe, a hollow oil drain pin is cut off under the impact action of the impact rod, and the hollow oil drain pin is communicated with the annular space between the oil pipe and an oil sleeve, so that the oil drain purpose is realized. Due to the working principle of the impact type oil drainer, the impact type oil drainer has the problem of unreliability of oil drainage when being applied to oil wells with special well conditions, such as highly-deviated wells, horizontal wells, ultra-thick oil and high-setting oil wells; for example, the oil pipe can lead to throwing difficulty when wax deposition and scaling are serious, or the impact force is small, the oil drain device cannot be opened, and the oil drainage effect cannot be achieved. If the well is in accident, the well cannot be thrown. Chinese patent application publication No. CN 108643859a discloses an oil drain device, which includes a central tube having a first through hole on a side wall thereof, an outer tube sleeved outside the central tube, an annular cavity formed between the outer tube and the central tube and communicated with the first through hole, the upper end and the lower end of the annular cavity being closed, a second through hole communicated with the annular cavity on the side wall of the outer tube, and a sliding sleeve sleeved outside the central tube and capable of moving in the annular cavity, wherein when the sliding sleeve is at a first working position, the sliding sleeve blocks the second through hole so that the first through hole cannot be communicated with the second through hole through the annular cavity; when the sliding sleeve is located at the second working position, the sliding sleeve removes the blockage of the second through hole, so that the first through hole is communicated with the second through hole through the annular cavity, however, according to the scheme, a pressure test vehicle is needed to pump high-pressure liquid into the oil pumping pipe column and suppress the pressure to cut the shearing pin, the sliding sleeve is switched from the first working position to the second working position, the operation process is complex, and the operation cost is high.

During normal production, the draining hole of rotation type bleeder upper joint relies on sealed reaching sealed effect between packing and the seal cover, guarantees that oil well production is normal. When operations such as pump detection, pipe string lifting and the like occur, the sucker rod string is lifted out, then the sucker rod string is rotated positively, the friction block is fixed relative to the casing wall under the friction action, the connecting body is meshed with the friction block through the claws, and the connecting body is in threaded connection with the upper joint, so that the connecting body does not rotate relative to the friction block and moves downwards, and the sealing sleeve moves downwards along with the connecting body through the positioning pin, so that the oil drainage hole achieves the purpose of oil drainage. The design of the rotary oil drain device thread is unreasonable, and the problems of immobility in rotation, damage to a friction block and incapability of rotating for final oil drainage can occur in secondary operation due to long-term corrosion and the like of well liquid. The application publication number is CN 101984215A's Chinese patent discloses an oil pipe bleeder, the bleeder connects on the oil-well pump, when next operation carried oil pipe and need the draining, carry oil pipe earlier, make convex key and convex key detain together, rotatory inner tube, under the frictional force effect between friction mechanism and sleeve pipe, friction mechanism, the seal cover is motionless, under the effect of rotary torque, the hookup screw thread of inner tube and seal cover is broken out, the seal cover goes upward, lose the cover to the draining hole, the inside and outside UNICOM draining of draining on the messenger inner tube hole, the mode in draining hole has been adopted in this scheme to rotatory opening, in case scale deposit or sand card seriously will lead to unable inner tube and seal cover connecting thread to break out, lead to unable opening the draining hole.

In addition, the baffle type oil drain device also needs to be pressed by a pump truck, so that the operation time is long and the operation cost is high. The lifting type oil drain device is easy to touch an oil drain switch to cause accidental leakage and poor in reliability. The supporting type oil drain device needs a Y211 packer for matching use, the cost is increased, the number of tail pipes is large, and the operation cost is high.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a location structure and bleeder of convertible work position to solve the problem that prior art exists above-mentioned, set up the frictional force of body between the fixed power of the shearing pin and the fixed power of soluble holding ring, can utilize soluble holding ring to guarantee at a work position, after the soluble holding ring became invalid, utilize the shearing pin to keep stable at this work position, when needing to get into another work position, can utilize frictional force to cut the shearing pin and change to another work position; the oil drain can be installed in place in a sealed state by utilizing the soluble positioning ring during the process of going into the well, the sealed state can be kept by utilizing the shearing pin during the oil pumping operation, and the shearing pin is sheared by utilizing the friction mechanism during the operation of pulling up the pipe column, so that the oil drainage hole is smoothly exposed to realize oil drainage.

In order to achieve the above object, the utility model provides a following scheme:

the utility model provides a location structure of convertible work position, slidable sets up in the intermediate layer, include the body and connect cut pin and soluble holding ring on the body, the body with interbedded a lateral wall friction connection, cut the pin with soluble holding ring all with interbedded another lateral wall fixed connection, the frictional force that the body received is greater than cut the stationary force of pin, be less than the stationary force of soluble holding ring.

Preferably, a friction mechanism is connected to the body and used for generating friction force with one side wall of the interlayer.

Preferably, the interlayer is formed by a central pipe and a sleeve sleeved outside the central pipe, the body is sleeved on the outer wall of the central pipe, the shearing pin and the soluble positioning ring are fixedly connected with the central pipe, and the friction mechanism is in friction connection with the inner wall of the sleeve.

The utility model also provides an oil drainer, use the record in the preceding the location structure of convertible work position, the intermediate layer is established by center tube and cover the outside sleeve pipe of center tube forms, the body includes that slidable cover establishes on the center tube outer wall and mutual fixed connection's draining cover and friction mechanism, friction mechanism be used for with sleeve pipe friction produces frictional force, be provided with the draining hole on the center tube, draining cover is used for sealing the draining hole.

Preferably, two ends of the friction mechanism are respectively connected with an upper pressing cap and a lower pressing cap, the upper pressing cap is connected with the oil discharge sleeve, and the lower pressing cap is connected with the shearing pin and the soluble positioning ring.

Preferably, the upper pressing cap comprises a hole shrinkage section and a hole expansion section, the oil drainage sleeve comprises a hole shrinkage section and a hole expansion section, and the hole expansion section is clamped in the hole expansion section and connected through threads.

Preferably, the oil drainage sleeve is provided with a guide nail, the outer wall of the central pipe is provided with a rotary guide groove, and the guide nail is clamped in the rotary guide groove.

Preferably, an upper joint is connected to the end portion, close to the oil drainage hole, of the central pipe, and the upper joint can abut against the end portion of the oil drainage sleeve.

Preferably, the friction mechanism comprises a spring seat, a spring arranged on the spring seat and a friction block abutted against the other end of the spring, an axial slot for installing the spring is formed in the spring seat, and two ends of the friction block are clamped on the inner sides of the upper pressure cap and the lower pressure cap.

Preferably, an insoluble positioning ring is arranged at the position of the shearing pin and connected to the lower pressing cap, and a positioning boss for limiting the axial position of the insoluble positioning ring is arranged on the central pipe.

The utility model discloses for prior art gain following technological effect:

(1) the friction force of the body is arranged between the fixing force of the shearing pin and the fixing force of the soluble positioning ring, the soluble positioning ring can be ensured to be at one working position, after the soluble positioning ring is dissolved and loses efficacy, the shearing pin is kept stable at the working position, and when the other working position needs to be entered, the shearing pin can be sheared by the friction force and is converted to the other working position;

(2) the utility model discloses be provided with friction mechanism and with it and through cutting pin and soluble holding ring fixed connection between the center tube, utilize the traction force of friction mechanism to be greater than the stationary force who cuts the pin, be less than the mode of the stationary force of soluble holding ring, can utilize soluble holding ring to guarantee to install in place with the encapsulated situation when going into the well, and can utilize to cut the pin and keep the encapsulated situation when the oil pumping operation, when the tubular column operation of playing, utilize friction mechanism to cut the pin, the draining hole exposes smoothly and realizes the draining;

(3) the upper pressure cap of the utility model comprises a hole shrinkage section and a hole expansion section, the oil drainage sleeve comprises a hole shrinkage section and a hole expansion section, the hole expansion section is clamped in the hole expansion section to realize the connection of the upper pressure cap and the oil drainage sleeve, that is, the oil drainage sleeve is clamped in the upper pressure cap to realize the stable connection of the oil drainage sleeve and the upper pressure cap, when the friction mechanism drives the upper pressure cap to move axially, the oil drainage sleeve can be smoothly driven to move, and the risk that the oil drainage hole cannot be opened is reduced;

(4) the utility model discloses be provided with the guide pin on the draining cover, be provided with rotatory guide way on the center tube outer wall, put the guide pin card in rotatory guide way, utilize rotatory guide way to lead the moving trajectory of guide pin, when the oil pumping operation, inevitable because the operation of oil-well pump can transmit the vibration to the bleeder to make it vibrate or wriggle, the setting of rotatory guide way can form certain constraint force to the guide pin, under the effect that cooperates jointly with the shearing pin, guarantee that the draining cover seals at the draining hole position, keep the encapsulated situation not destroyed;

(5) the utility model discloses be provided with insoluble holding ring cutting the pin position, insoluble holding ring is connected on pushing down the cap, utilizes the location boss that sets up on the center tube, prescribes a limit to the axial position of insoluble holding ring to can prescribe a limit to let out the position of oil jacket axial displacement, avoid the center tube that drops, can reuse after reseing.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic view of the state of the oil drainage hole sealed by the oil drainage sleeve of the present invention;

FIG. 2 is a schematic view of the oil drainage hole of the present invention in a state after being exposed;

wherein, 1, an upper joint; 2. a central tube; 3. an oil drainage sleeve; 4. pressing the cap upwards; 5. a guide pin; 6. fixing the pin; 7. a friction block; 8. a spring; 9. a spring seat; 10. an insoluble positioning ring; 11. shearing off the pin; 12. pressing down the cap; 13. a soluble positioning ring; 14. a rotary guide groove; 15. and an oil drainage hole.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The utility model aims at providing a positioning structure capable of converting working positions and an oil drainer thereof, which can solve the problems existing in the prior art, the friction force of a body is arranged between the fixing force of a shearing pin and the fixing force of a soluble positioning ring, the soluble positioning ring can be utilized to ensure one working position, after the soluble positioning ring fails, the shearing pin is utilized to keep stable at the working position, when the other working position needs to be entered, the shearing pin can be sheared by the friction force and converted to the other working position; the oil drain can be installed in place in a sealed state by utilizing the soluble positioning ring during the process of going into the well, the sealed state can be kept by utilizing the shearing pin during the oil pumping operation, and the shearing pin is sheared by utilizing the friction mechanism during the operation of pulling up the pipe column, so that the oil drainage hole is smoothly exposed to realize oil drainage.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.

As shown in fig. 1-2, the present invention provides a positioning structure capable of converting a working position, which is slidably disposed in an interlayer, wherein the interlayer can be an annular interlayer sleeved inside and outside, a planar interlayer formed between two flat plates, or an interlayer of other forms, for example, an interlayer between two rods can also be called an interlayer. The positioning structure comprises a body, a shear pin 11 and a soluble positioning ring 13, wherein the shear pin 11 is connected to the body, the soluble positioning ring 13 can be cut off after being subjected to certain shearing force, the shearing force can be selected according to the structure and the material of the shear pin 11, and the shearing force corresponding to the corresponding structure and the material can be determined through experiments. The soluble positioning ring 13 can be dissolved and lose its fixing force by being immersed in water or other liquid, the dissolving time and the dissolved liquid can be obtained by the prior art, and the corresponding materials can be selected according to the dissolving time, and the magnitude of the fixing force can be selected according to the materials and the structure. The body is in frictional connection with one side wall of the interlayer, namely, frictional force can be generated between the body and the interlayer. The cutting pin 11 and the soluble positioning ring 13 are fixedly connected with the other side wall of the interlayer, namely, the cutting pin 11 and the soluble positioning ring 13 can apply certain fixing force to the body. The friction force and the fixing force act on the body in opposite directions, and the working position of the body can be switched by utilizing the friction force. Specifically, the friction force applied to the body is greater than the fixing force of the cutting pin 11 and less than the fixing force of the soluble positioning ring 13, that is, before the soluble positioning ring 13 is not dissolved, the soluble positioning ring 13 can be used for protecting the cutting pin 11 from being damaged, so that the cutting pin can smoothly enter one working position, after the soluble positioning ring 13 is dissolved and failed, the cutting pin 11 is continuously kept stable at the working position, and when the cutting pin needs to enter another working position, the friction force applied to the body can be used for cutting the cutting pin 11 and converting the cutting pin into the other working position.

The friction mechanism can be connected to the body and used for generating friction force with one side wall of the interlayer, on one hand, the friction mechanism can be used for generating friction force with a specific size, and on the other hand, the body is prevented from directly rubbing with one side wall to damage the structure of the body.

Further, the interlayer can be formed by the central tube 2 and a sleeve sleeved outside the central tube 2, at the moment, the interlayer is of an annular structure, the body is sleeved on the outer wall of the central tube 2, the shearing pin 11 and the soluble positioning ring 13 are fixedly connected with the central tube 2, namely fixed on the outer wall of the central tube 2 to form a fixing force, and the friction mechanism is in friction connection with the inner wall of the sleeve to generate a friction force.

Referring to fig. 1-2 again, the present invention further provides an oil drain device, which can use the above-mentioned positioning structure with convertible working positions, wherein the interlayer is formed by the central tube 2 and the sleeve sleeved outside the central tube 2, the body comprises an oil drain sleeve 3 slidably sleeved on the outer wall of the central tube 2 and fixedly connected with each other and a friction mechanism, the friction mechanism is used for generating friction force with the sleeve, the friction force generated by the friction mechanism can drive the oil drain sleeve 3 to axially slide on the outer wall of the central tube 2 (after the soluble positioning ring 13 is dissolved and failed and the cutting pin 11 is cut off), the central tube 2 is provided with an oil drain hole 15, the oil drain sleeve 3 is used for sealing the oil drain hole 15, that is, the working position of the oil drainage sleeve 3 for sealing the oil drainage hole 15 can be formed at the moving position of the oil drainage sleeve 3, and the working position of the oil drainage sleeve 3 exposed out of the oil drainage hole 15 can also be formed. Specifically, the soluble positioning ring 13 can be used for ensuring that the oil pumping pipe is installed in place in a sealing state during the well descending process, the shearing pin 11 can be used for keeping the sealing state during the oil pumping operation, the friction mechanism is used for shearing the shearing pin 11 during the pipe string lifting operation, and the oil drainage hole 15 is exposed smoothly to realize oil drainage. In addition, in order to ensure the sealing effect of the oil drainage hole 15 sealed by the oil drainage sleeve 3, sealing rings can be arranged on the inner wall of the oil drainage sleeve 3 and are positioned on two sides of the oil drainage hole 15.

The two ends of the friction mechanism can be respectively connected with an upper pressing cap 4 and a lower pressing cap 12, and the upper pressing cap 4 and the lower pressing cap 12 can be the composition structure of the friction mechanism or the additional structure connected to the friction mechanism. Go up and press cap 4 to be connected with draining cover 3, adopt detachable connected mode such as threaded connection during the connection, can establish on center tube 2 earlier draining 3 covers of oil jacket, establish outside last cap 4 of pressing from a pot head of draining cover 3. The lower pressing cap 12 is connected with the shearing pin 11 and the soluble positioning ring 13, detachable connection modes such as threaded connection and the like can be adopted during connection, and the soluble positioning ring 13 and the shearing pin 11 are integrally sleeved on the central tube 2 after being arranged in the lower pressing cap 12.

The upper pressing cap 4 may include a hole-reducing section and a hole-expanding section, that is, the inside of the upper pressing cap 4 is a stepped hole structure. The oil drainage sleeve 3 comprises a reduced diameter section and an enlarged diameter section, i.e. the oil drainage sleeve 3 is in the form of a stepped shaft. The diameter expanding section of the oil discharge sleeve 3 is clamped in the hole expanding section of the upper pressure cap 4 and is connected through threads. Realize letting out oil jacket 3 and last pressure cap 4's firm connection, drive that can be smooth when pressing cap 4 axial displacement in the drive of friction mechanism lets out oil jacket 3 and removes, reduces the risk that can't open draining hole 15.

Be provided with guide pin 5 on the oil drainage cover 3, guide pin 5 can be fixed set up in oil drainage cover 3 and extend one section to the internal diameter side of oil drainage cover 3, is provided with rotatory guide way 14 on the 2 outer walls of center tube, and guide pin 5's extension section card is put in rotatory guide way 14. The moving track of the guide pin 5 is guided by the rotary guide groove 14. During oil pumping operation, vibration is inevitably transmitted to the oil drain device due to the operation of the oil well pump so that the oil drain device vibrates or creeps, certain constraint force for the guide nail 5 can be formed by the arrangement of the rotary guide groove 14, and the oil drain sleeve 3 is ensured to be sealed at the oil drain hole 15 under the action of cooperation with the shearing pin 11, so that the sealing state is kept from being damaged.

The end connection that the center tube 2 is close to the draining hole 15 has top connection 1, top connection 1 threaded connection is on center tube 2, the external diameter of top connection 1's external diameter protrusion center tube 2's external diameter, and, top connection 1 can the butt leak the tip of oil jacket 3, that is to say, top connection 1 can form the limit structure who prescribes a limit to the 3 axial position of oil jacket, thereby can block to leak the direction removal of oil jacket 3 to keeping away from the oil pumping well, when the tubular column is gone down promptly, can guarantee together with soluble holding ring 13 that the oil jacket 3 department is in the position of sealed draining hole 15, avoid together that pin cutting 11 takes place to cut when the tubular column is gone down.

Friction mechanism can include spring holder 9, the spring holder 9 cover is established on 2 outer walls of center tube and can be at the axial slip, be provided with the axial fluting on the spring holder 9, be provided with a plurality of springs 8 in the axial fluting, spring 8's other end butt has clutch blocks 7, clutch blocks 7 can move along the radial direction of center tube 2, and receive the elasticity of spring 8 to the radial outside, clutch blocks 7's both ends joint is at last cap 4 and the inboard of cap 12 that pushes down, thereby can inject the position relation between clutch blocks 7 and the spring holder 9, and, on press cap 4 and cap 12 all can carry out fixed connection through fixing pin 6 and spring holder 9 down.

The position of the cutting pin 11 can be provided with an insoluble positioning ring 10, the insoluble positioning ring 10 is connected on a lower pressing cap 12, and the insoluble positioning ring can be connected in a detachable mode through threads or other fixed connection modes such as welding and the like. Be provided with the location boss of injecing insoluble holding ring 10 axial position on the center tube 2, utilize the location boss that sets up on the center tube 2, can injecing insoluble holding ring 10's axial position to can inject the position of letting out 3 axial displacement of oil jacket, avoid dropping center tube 2, reuse after can reseing when using next time.

The working principle of the utility model is as follows:

1. install the bleeder on center tube 2 on oil-well pump upper portion, be provided with between center tube 2 and the lower pressure cap 12 and cut pin 11 and soluble holding ring 13, soluble holding ring 13 can the lock joint, also can with press down threaded connection between cap 12 and the center tube 2, the soluble holding ring 13 of bleeder just can dissolve in the settlement time, when putting the tubular column, the frictional force that friction block 7 and sheathed tube pipe wall produced is undertaken by soluble holding ring 13, at this moment, the bleeder can firmly be fixed on center tube 2, that is to say, the bleeder can not move, draining cover 3 can seal on draining hole 15.

2. When the pipe string is lifted, the soluble positioning ring 13 is dissolved, the axial limiting of the oil drain device is released, the friction block 7 generates resistance with the sleeve under the action of the elastic force of the spring 8 when the pipe string is lifted, so that the small-diameter shearing pin 11 for preventing the oil from falling off is sheared, at the moment, the oil drain sleeve 3, the upper pressing cap 4, the friction block 7, the spring 8, the spring seat 9, the insoluble positioning ring 10 and the lower pressing cap 12 move downwards along the rotary guide groove 14 under the driving of the guide pin 5, the oil drain hole 15 on the central pipe 2 is exposed, and automatic oil drain is realized.

The utility model discloses a concrete example is applied to explain the principle and the implementation mode of the utility model, and the explanation of the above example is only used to help understand the method and the core idea of the utility model; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the concrete implementation and the application scope. In summary, the content of the present specification should not be construed as a limitation of the present invention.

Claims (10)

1. A positioning structure capable of converting a working position is characterized in that: but the slidable sets up in the intermediate layer, include the body and connect cut pin and soluble holding ring on the body, the body with a lateral wall frictional connection of intermediate layer, cut the pin with soluble holding ring all with another lateral wall fixed connection of intermediate layer, the frictional force that the body received is greater than the stationary force of cutting the pin is less than the stationary force of soluble holding ring.

2. The convertible working position positioning structure of claim 1, further comprising: the friction mechanism is connected to the body and used for generating friction force with one side wall of the interlayer.

3. The convertible working position positioning structure of claim 2, further comprising: the interlayer is formed by a central pipe and a sleeve sleeved outside the central pipe, the body is sleeved on the outer wall of the central pipe, the shearing pin and the soluble positioning ring are fixedly connected with the central pipe, and the friction mechanism is in friction connection with the inner wall of the sleeve.

4. An oil drainer, which is characterized in that: the convertible working position positioning structure according to any one of claims 1 to 3, wherein the interlayer is formed by a central tube and a sleeve sleeved outside the central tube, the body comprises an oil drainage sleeve slidably sleeved on the outer wall of the central tube and fixedly connected with each other and a friction mechanism, the friction mechanism is used for generating friction force with the sleeve, an oil drainage hole is formed in the central tube, and the oil drainage sleeve is used for sealing the oil drainage hole.

5. The oil drain of claim 4, wherein: the two ends of the friction mechanism are respectively connected with an upper pressing cap and a lower pressing cap, the upper pressing cap is connected with the oil discharge sleeve, and the lower pressing cap is connected with the shearing pin and the soluble positioning ring.

6. The oil drain of claim 5, wherein: the upper pressing cap comprises a reducing section and a reaming section, the oil drainage sleeve comprises a reducing section and a reaming section, and the reaming section is clamped in the reaming section and is connected with the reaming section through threads.

7. The oil drain of claim 5 or 6, wherein: the oil drainage sleeve is provided with a guide nail, the outer wall of the central pipe is provided with a rotary guide groove, and the guide nail is clamped in the rotary guide groove.

8. The oil drain of claim 7, wherein: the end part of the central tube, which is close to the oil drainage hole, is connected with an upper joint, and the upper joint can be abutted to the end part of the oil drainage sleeve.

9. The oil drain of claim 7, wherein: the friction mechanism comprises a spring seat, a spring arranged on the spring seat and a friction block abutted against the other end of the spring, an axial slot for installing the spring is formed in the spring seat, and two ends of the friction block are clamped on the inner sides of the upper pressure cap and the lower pressure cap.

10. The oil drain of claim 7, wherein: an insoluble positioning ring is arranged at the position of the shearing pin and connected to the lower pressing cap, and a positioning boss for limiting the axial position of the insoluble positioning ring is arranged on the central tube.

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