CN210460555U

CN210460555U - Expansion piece capable of being unsealed step by step

Info

Publication number: CN210460555U
Application number: CN201921275617.9U
Authority: CN
Inventors: 周晓东; 刘中桂; 张晓明; 李江龙
Original assignee: Beijing Jinkelong Petroleum Technology Development Co ltd
Current assignee: Beijing Jinkelong Petroleum Technology Development Co ltd
Priority date: 2019-08-07
Filing date: 2019-08-07
Publication date: 2020-05-05
Anticipated expiration: 2029-08-07

Abstract

The utility model discloses a gradual deblocking expansion piece, which belongs to the field of oil fracturing, and adopts the technical scheme that the gradual deblocking expansion piece comprises a top connecting joint, a middle pipe, an outer pipe, a bottom connecting joint, a sliding sleeve, a butting groove, a butting block, an elastic piece, a necking part, a through groove, a clamping block and a guide ring, wherein the outer side wall of the guide ring extends out of the outer side wall of the middle pipe and is butted with the inner side wall of the outer pipe; when the lateral wall of fixture block was simultaneously with the inside wall of draw-in groove and the inside wall butt of leading to the groove, the bottom of top link and the top butt of outer tube. The utility model discloses reached and to have made the more convenient effect of taking out of a plurality of packers, be applied to in the fracturing method acquires the oil.

Description

Expansion piece capable of being unsealed step by step

Technical Field

The utility model relates to an oil fracturing field, more specifically the theory that says so, it relates to a gradual deblocking expansion bend.

Background

After the oil well is produced to a certain stage, the productivity and the permeability are reduced, and in order to enhance the oil discharge capacity and improve the oil well yield, people use the fracturing technology. The hydraulic fracturing method comprises two categories of hydraulic fracturing and high-energy gas fracturing, wherein the hydraulic fracturing is that fluid is injected into a well at a high speed by a ground high-pressure pump truck group, and the rock of an oil layer is fractured to generate cracks by means of high pressure pumped up from the bottom of the well. In order to prevent the pressure from dropping and the crack from closing after the pump truck stops working, sand which is several times higher than the density of the stratum is mixed in the injected liquid after the stratum is broken, the sand and the fluid enter the crack and stay in the crack permanently, and the supporting crack is in an open state, so that the oil flow environment is improved for a long time.

In the process of obtaining oil at the fracturing method, often adopt the packer to separate sealed to the petroleum reservoir of different degree of depth levels, but when petroleum reservoir more than or equal to six layers, the quantity of packer is more, receives the dead weight of packer still the influence of the great frictional force between packer and stratum or the oil absorption pipe, and the user often is difficult to once only take out all packers, consequently needs a product that can convenient to use person takes out the packer.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a not enough to prior art exists, the utility model provides a progressively deblocking expansion bend, it passes through outer tube, well pipe, sliding sleeve, sets up the draw-in groove on the outer tube, sets up logical groove on well pipe, pegs graft at draw-in groove and the fixture block that leads to inslot portion and set firmly the guide ring on well pipe lateral wall, can provide certain displacement volume for partly packer earlier when packer quantity is more, and the user can take out partly packer earlier, takes out remaining packer again.

In order to achieve the above purpose, the utility model provides a following technical scheme: a gradually-deblocking expansion piece comprises a top connecting joint, wherein a middle pipe arranged along the length direction of the top connecting joint is in threaded connection with the top connecting joint, one end of the middle pipe extends out of the top connecting joint, an outer pipe which is sleeved on the outer side wall of the middle pipe and is arranged along the length direction of the middle pipe is detachably connected to the middle pipe, the end, extending out of the top connecting joint, of the middle pipe is inserted into the outer pipe, and the end, back to the top connecting joint, of the outer pipe is detachably connected with a bottom connecting joint matched with the top connecting joint; the inner part of the middle pipe is connected with a sliding sleeve arranged along the length direction in a sliding manner, the outer side wall of the sliding sleeve is provided with a butt groove sunken towards the inner part of the sliding sleeve, the butt groove penetrates through the side wall of the sliding sleeve along the direction of a bottom connecting joint, a butt block with a rotating axis vertical to the length direction of the sliding sleeve is hinged inside the butt groove, an elastic piece for driving the butt block to butt against the inner side wall of the middle pipe is arranged on the inner side wall of the butt groove, and a necking part is arranged inside the sliding sleeve; the side wall of the middle pipe is provided with a plurality of through grooves which are uniformly distributed along the circumferential direction, the inner side walls of the through grooves are continuously drawn in from the inner side wall of the middle pipe to the outer side wall of the middle pipe, the inner side wall of the outer pipe is provided with a plurality of clamping grooves matched with the through grooves, the inner side walls of the clamping grooves are continuously drawn in along the direction of the middle pipe towards the outer pipe, the inner side walls of the clamping grooves and the inner side walls of the through grooves are in smooth transition, and clamping blocks matched with the through grooves; the outer pipe comprises a clamping pipe provided with a clamping groove and a main pipe in threaded connection with the clamping pipe, the end part of the clamping pipe, which is back to the top connecting joint, is positioned inside the main pipe, the inner diameter of the clamping pipe inside the main pipe is smaller than the inner diameter of the main pipe, an annular guide ring is fixedly arranged on the outer side wall of the limiting pipe, and the outer side wall of the guide ring extends out of the outer side wall of the middle pipe and is abutted against the inner side wall of the outer pipe; when the lateral wall of fixture block was simultaneously with the inside wall of draw-in groove and the inside wall butt of leading to the groove, the bottom of top link and the top butt of outer tube.

Through adopting above-mentioned technical scheme, after the oil well produced certain stage, productivity and permeability reduce, in order to strengthen the oil extraction ability, improve oil well output, people's utility model fracturing technology. The hydraulic fracturing method comprises two categories of hydraulic fracturing and high-energy gas fracturing, wherein the hydraulic fracturing is that fluid is injected into a well at a high speed by a ground high-pressure pump truck group, and the rock of an oil layer is fractured to generate cracks by means of high pressure pumped up from the bottom of the well. Get the oil through the mode of fracturing and often go down the sheathed tube assigned position in the deep hole with multilayer fracturing tubular column to the fracturing tubular column that four layers of oil reservoirs are suitable for as an example, including the top seal packer who distributes from bottom to top in proper order seals switch, sealing joint, packer, sliding sleeve switch, expansion bend, packer, sliding sleeve switch and top. When the packer is used, a fracturing string is lowered to a specified position in a casing, then a sealing ball (ball for a setting switch) is put into the casing, the pressure is slowly increased to 15MPa and stabilized for 5 minutes, and after the packer is completely set, the pressure is increased to 22MPa, the setting switch is opened, so that the first layer at the lowest part is communicated. Then, the bottom of the sleeve in the deep hole is filled with fluid mixed with sand which is several times higher than the density of the stratum, after the construction of the first layer at the bottom is completed, another sealing ball is thrown in and applies pressure (the diameter of the sealing ball thrown in each time is increased in sequence), the sealing ball can fall into the sliding sleeve switch on the second layer and form sealing with the sliding sleeve inside the sliding sleeve switch, along with the pressure application to the cavity where the sealing ball is located, the sliding sleeve inside the sliding sleeve switch can be opened, the sealing ball and the sliding sleeve inside the sliding sleeve switch fall together, the sealing ball falls into the sealing joint below after passing through the packer below and forms sealing with the sealing joint, so that the first layer at the bottom is separated from the second layer, and the fracturing construction can be carried out on the oil layer of the second layer. After the construction is accomplished to the second floor, drop into the sealed ball that the third layer oil reservoir was suitable for, this sealed ball falls inside the sliding sleeve switch of third layer and forms sealedly, under lasting the application, this sealed ball can fall with the sliding sleeve of this sliding sleeve switch together to fall inside the expansion bend through the packer, and form sealedly with the inside sliding sleeve of expansion bend, just so separate second floor and third layer, the user just can carry out the fracturing construction to the oil reservoir of third layer. At the in-process to third layer fracturing construction, through the pressure applied to the ball sealer for the sliding sleeve removes to the bottom of well pipe, when the sliding sleeve removed the lateral wall of sliding sleeve not with the fixture block butt, the fixture block no longer received the spacing effect that the sliding sleeve provided, the fixture block just can break away from in the draw-in groove even drop inside the sliding sleeve this moment, well pipe no longer locked and can the rebound this moment promptly, after the user is accomplished the third layer construction according to the mode the same with the third layer construction to the fourth layer construction at top can. When the packer needs to be taken out, because the expansion pieces are released in the fracturing process, when the pipe column is lifted up, the packer is firstly unsealed at the upper end of the first expansion piece from top to bottom, the pipe column is continuously lifted up after the unsealing is finished, and the packer at the upper end of the second expansion piece is continuously unsealed, so that all the packers are gradually unsealed and smoothly taken out.

Preferably, the following steps: the elastic component includes the cyclic annular leaf spring with sliding sleeve fixed connection, and the tip threaded connection that well pipe dorsad top link has the spacing pipe that sets up with the sleeve pipe coaxial line, and spacing pipe is just seted up on the tip inside wall of well pipe with cyclic annular leaf spring complex spacing groove.

Preferably, the following steps: when the annular leaf spring is abutted to the inner part of the limiting groove, the annular leaf spring is in a compressed state, and the inner side wall of the abutting groove is abutted to the inner side wall of the limiting pipe at the limiting groove.

Through adopting above-mentioned technical scheme, can apply along well pipe length direction's spacing through cyclic annular leaf spring to the sliding sleeve, can apply perpendicular to and well pipe length direction spacing to the sliding sleeve through the lateral wall in butt joint groove and the inside wall butt of spacing pipe simultaneously.

Preferably, the following steps: the middle pipe is in threaded connection with a limiting ring on the end part opposite to the top connecting joint, and the inner side wall of the limiting ring and the inner side wall of the sliding sleeve opposite to the top connecting joint end are located on the same cylindrical surface.

Through adopting above-mentioned technical scheme, can exert spacingly to the route of sliding sleeve through the spacing ring, reduce the sliding sleeve from well pipe and the possibility of top coupling link roll-off.

Preferably, the following steps: the limiting ring is provided with an annular inclined plane part on the end face, opposite to the top connecting joint, of the limiting ring, the inclined plane part is arranged towards the center of the inner portion of the limiting ring, and the annular inclined plane part and the sliding sleeve are arranged coaxially.

Through adopting above-mentioned technical scheme, can exert the guide effect for the ball sealer through the inclined plane portion for the ball sealer wants the inside process that slides of sliding sleeve more smooth and easy after through the top link, has reduced the possibility that produces the collision between ball sealer and the spacing ring, has prolonged the life of spacing ring, can make the ball sealer can more direct fall on the intermediate position department of throat portion simultaneously, has reduced the possibility that ball sealer and sliding sleeve inside wall produced the collision.

Preferably, the following steps: the limiting groove is internally and fixedly provided with a thickened pipe arranged along the length direction, and when the annular leaf spring is abutted to the inner part of the limiting groove, the end part of the sliding sleeve, which is just opposite to the bottom connecting joint, is abutted to the end part of the thickened pipe, which is back to the bottom connecting joint.

Through adopting above-mentioned technical scheme, can be when annular leaf spring butt is inside the spacing inslot, through the top of thickening pipe and the bottom butt of sliding sleeve, realize the support to the sliding sleeve, reduce the pressure that annular leaf spring received, prolonged annular leaf spring's life.

Preferably, the following steps: the fixture block is in a round table shape with the axis perpendicular to the axis of the middle pipe, and one end of the smaller end face of the round table-shaped fixture block faces the outer pipe.

Through adopting above-mentioned technical scheme, the fixture block of round platform form can be more smooth and easy from the inside roll-off of draw-in groove, the job stabilization nature has been improved, and simultaneously, because the fixture block is released at the fracturing process, need not singly to open, when carrying out fracturing construction to the oil reservoir of expansion bend below promptly, the top link passes through the fixture block with the bottom link even as an organic whole, there is not the displacement volume between the two, when carrying out fracturing construction to the oil reservoir of expansion bend top, the fixture block is released in the work progress, this is just so that top link and bottom link mutually independent, the construction degree of difficulty of taking out the process of follow-up packer has been reduced.

Preferably, the side wall of the fixture block, which is opposite to the sliding sleeve, is in an arc surface shape matched with the outer side wall of the sliding sleeve.

Through adopting above-mentioned technical scheme, can make the fixture block can more laminate with the lateral wall butt of sliding sleeve, can let the more stable stop of sliding sleeve on a certain height, reduce between sliding sleeve and the fixture block the butt unstability lead to the sliding sleeve to be difficult to the possibility of stable stop at a certain height.

Preferably, the following steps: first sealing rings are fixedly arranged on the inner wall of the middle pipe at the position of the limiting ring and the outer side wall of the position, where the sliding sleeve is provided with the butting groove.

To sum up, the utility model discloses compare and have following beneficial effect in prior art:

1. through the outer pipe, the middle pipe, the sliding sleeve, the clamping groove formed in the outer pipe, the through groove formed in the middle pipe, the clamping block inserted in the clamping groove and the through groove and the guide ring fixedly arranged on the side wall of the middle pipe, a certain displacement can be provided for a part of packers when the number of the packers is large, a user can take out the part of packers firstly and then take out the rest packers;

2. the annular leaf spring can limit the sliding sleeve in the length direction of the middle pipe, meanwhile, the limit perpendicular to the length direction of the middle pipe can be applied to the sliding sleeve by abutting the side wall of the abutting groove and the inner side wall of the limiting pipe, and the reinforcing pipe can support the sliding sleeve by abutting the top end of the thickening pipe and the bottom end of the sliding sleeve when the annular leaf spring abuts inside the limiting groove, so that the pressure applied to the annular leaf spring is reduced, and the service life of the annular leaf spring is prolonged;

3. the fixture block is released at the fracturing in-process, need not singly to open, and when carrying out fracturing construction to the oil reservoir of expansion bend below, top link passes through the fixture block with the bottom link and links in an organic whole, does not have the displacement volume between the two, when carrying out fracturing construction to the oil reservoir of expansion bend top, the fixture block is released in the work progress, and this just makes top link and bottom link mutually independent, has reduced the construction degree of difficulty of follow-up packer's the process of taking out.

Drawings

FIG. 1 is a schematic view of an embodiment;

FIG. 2 is an enlarged view of portion A of the stopper ring structure of FIG. 1;

FIG. 3 is an enlarged view of a portion B of FIG. 1 showing the structure of the throat portion;

FIG. 4 is an enlarged view of the portion C of FIG. 1 showing the position of the abutment block;

FIG. 5 is an enlarged view of the portion D of FIG. 1 showing the position of the limit groove;

fig. 6 is an enlarged view of a portion E showing the position of the guide ring in fig. 1.

Reference numerals: 1. a top connecting joint; 11. a bottom connecting joint; 2. a middle tube; 21. a through groove; 22. a first shear pin; 3. a sliding sleeve; 31. a necking part; 32. a butt joint groove; 33. a second shear pin; 34. a butting block; 35. an elastic member; 36. an annular leaf spring; 4. an outer tube; 41. clamping the pipe; 411. a card slot; 412. a connecting portion; 42. a main pipe; 421. connecting grooves; 5. a limiting pipe; 51. a limiting groove; 52. thickening the pipe; 53. a guide ring; 54. a plug-in part; 6. a limiting ring; 61. an inclined plane part; 7. a clamping block; 8. and (5) sealing rings.

Detailed Description

Example (b): the utility model provides a gradual deblocking expansion bend, refers to fig. 1 and fig. 2, including the tubulose top coupling 1 of both ends intercommunication, the axis vertical setting of top coupling 1, the inside threaded connection in bottom of top coupling 1 has well pipe 2 with top coupling 1 coaxial line setting, well pipe 2's top is located inside top coupling 1, and the bottom stretches out top coupling 1 outside. The top inside wall of well pipe 2 is threaded connection has spacing ring 6 rather than the coaxial line setting, and annular inclined plane portion 61 has been seted up at 6 inside wall tops of spacing ring, and inclined plane portion 61 sets up towards the top that 6 inside central points of spacing ring put, and annular inclined plane portion 61 sets up with spacing ring 6 coaxial line. The well 2 inside length direction along well pipe 2 of pipe of spacing ring 6 below slides and is connected with sliding sleeve 3, and the inside wall of sliding sleeve 3, the inside wall of spacing ring 6 and the inside wall of top link 1 all are located same face of cylinder. Sliding sleeve 3 sets up with well 2 coaxial lines, fixedly connected with and the sealing washer 8 that 6 coaxial lines of spacing ring set up on well 2 inside walls of spacing ring 6 below, and during the top of sliding sleeve 3 and the bottom butt of spacing ring 6, the inside wall of the inside sealing washer 8 of the connecting well 2 inside walls and the lateral wall butt of sliding sleeve 3. Well pipe 2 is last to dismantle and to be connected with outer tube 4, and outer tube 4 sets up with well pipe 2 coaxial line, and outer tube 4 includes can dismantle the card pipe 41 of being connected and can dismantle the person in charge 42 of being connected with card pipe 41 with well pipe 2, and well 2 inside threaded connection of card pipe 41 below has the spacing pipe 5 that sets up with well pipe 2 coaxial line. The bottom end of the main pipe 42 is screwed with a bottom connection joint 11 which is a tubular member with two communicated ends.

Referring to fig. 3 and 4, the outer side wall of the middle pipe 2 below the top connecting section 1 is fixedly connected with a first shear pin 22 perpendicular to the axis of the middle pipe 2, one end of the first shear pin 22 is fixedly connected with the middle pipe 2, the other end of the first shear pin is fixedly connected with a clamping pipe 41, the outer side wall of the middle pipe 2 below the first shear pin 22 is also fixedly connected with a sealing ring 8 coaxially arranged with the middle pipe 2, and when the middle pipe 2 is connected with the clamping pipe 41 by the first shear pin 22, the outer side wall of the sealing ring 8 connected to the middle pipe 2 is abutted to the inner side wall of the clamping pipe 41. The well 2 lateral walls of well pipe of 8 below of sealing washer of connection on well pipe 2 are seted up and are run through logical groove 21 of well pipe 2 lateral wall along the axis direction of well pipe 2 in the perpendicular to, lead to groove 21 and have four and along circumference evenly distributed on well pipe 2's lateral wall, two adjacent logical grooves 21 are each other not communicated. Offer on the inside wall of card pipe 41 with lead to groove 21 complex draw-in groove 411, draw-in groove 411 all draws in along well 2 inside wall towards the lateral wall direction of outer tube 4 with the lateral wall that leads to groove 21 smoothly, and when first shear pin 22 will card pipe 41 and well 2 connection, draw-in groove 411 and lead to the two coaxial line setting of groove 21 and communicate mutually, lead to the cross-section of the cell body structure that groove 21 and draw-in groove 411 formed this moment and become horizontal isosceles trapezoid shape. The clamping groove 411 and the through groove 21 are internally and jointly provided with the truncated cone-shaped clamping block 7. Offer on the card pipe 41 bottom outside wall of draw-in groove 411 below along vertical downward direction run through the annular of the lateral wall of card pipe 41 and form the tubulose connecting portion 412 of circle with well pipe 2 coaxial line setting, offer the spread groove 421 with the coaxial line setting of being responsible for 42 on the top inside wall of being responsible for 42, connecting portion 412 threaded connection is inside spread groove 421, and connecting portion 412 just is just to the lateral wall butt of well pipe 2 with spread groove 421 to the lateral wall of being responsible for 42, the top of being responsible for 42 and the card pipe 41 terminal surface butt of the department of the top of connecting portion 412, be responsible for 42 not with well pipe 2 butt, the inside bottom surface butt of connecting portion 412 bottom and spread groove 421, and the bottom end surface of connecting portion 412 only has. A necking part 31 extending towards the inside of the sliding sleeve 3 is arranged in the middle position of the inner side wall of the sliding sleeve 3. Set up on the bottom lateral wall of sliding sleeve 3 has a ring groove shaped butt groove 32, and the butt groove 32 runs through the lateral wall of sliding sleeve 3 along vertical decurrent direction, and the butt groove 32 runs through the lateral wall of spout along the lateral wall direction of the inside wall of sliding sleeve 3 towards sliding sleeve 3. The inside fixedly connected with of butt groove 32 is perpendicular to the second shear pin 33 that the 3 axes of sliding sleeve set up, the one end and the 3 fixed connection of sliding sleeve of second shear pin 33, and the other end articulates there is the butt piece 34 that the axis level set up that rotates, and second shear pin 33 has four and follows contour evenly distributed inside butt groove 32. The side wall of the abutting groove 32 below the second shear pin 33 is provided with a ring groove-shaped elastic placing groove, the elastic piece 35 is fixedly connected inside the elastic piece 35 placing groove, the driving abutting block 34 abuts against the elastic piece 35 on the inner side wall of the middle pipe 2, the elastic piece 35 in the embodiment is an annular leaf spring 36, and when the abutting block 34 abuts against the side wall of the inner pipe, the annular leaf spring 36 is in a compressed state.

Referring to fig. 4 and 5, a ring-groove-shaped limiting groove 51 is formed at the top end of the inner side wall of the limiting pipe 5, the limiting groove 51 is matched with the ring-shaped leaf spring 36, a thickened pipe 52 which is coaxial with the limiting pipe 5 is fixedly arranged on the inner side wall of the limiting pipe 5, when the ring-shaped leaf spring 36 abuts against the inside of the limiting groove 51, the ring-shaped leaf spring 36 is in a natural state, and the bottom end of the sliding sleeve 3 abuts against the top end face of the thickened pipe 52.

Referring to fig. 4 and 6, an annular groove is formed on the side wall of the bottom end of the limiting pipe 5 and forms a tubular connecting portion 412 which is coaxially arranged with the limiting pipe 5, and the connecting portion 412 is inserted into the bottom connecting joint 11.

It is above only the utility model discloses a preferred embodiment, the utility model discloses a scope of protection does not only confine above-mentioned embodiment, the all belongs to the utility model discloses a technical scheme under the thinking all belongs to the utility model discloses a scope of protection. It should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A progressively unsealing expansion piece, characterized in that: the pipe-shaped connecting joint comprises a tubular top connecting joint (1) with two communicated ends, wherein a middle pipe (2) arranged along the length direction of the top connecting joint is connected to the top connecting joint (1) in a threaded manner, one end of the middle pipe (2) extends out of the top connecting joint (1), an outer pipe (4) which is sleeved on the outer side wall of the middle pipe (2) and is arranged along the length direction of the middle pipe (2) is detachably connected to the middle pipe (2), the end part of the middle pipe (2), which extends out of the top connecting joint (1), is inserted into the outer pipe (4), and the end part, back to the top connecting joint (1), of the outer pipe (4) is detachably connected with a bottom connecting joint (11);

the middle pipe (2) is connected with a sliding sleeve (3) which is arranged along the length direction in a sliding manner along the length direction, the outer side wall of the sliding sleeve (3) is provided with a butt joint groove (32) which is sunken towards the inside of the sliding sleeve (3), the butt joint groove (32) penetrates through the side wall of the sliding sleeve (3) along the direction of a bottom connecting joint (11), a butt joint block (34) with a rotating axis vertical to the length direction of the sliding sleeve (3) is hinged inside the butt joint groove (32), an elastic piece (35) which drives the butt joint block (34) to butt against the inner side wall of the middle pipe (2) is arranged on the inner side wall of the butt joint groove (32), and a necking part (31) is arranged inside the;

the side wall of the middle pipe (2) is provided with a plurality of through grooves (21) which are uniformly distributed along the circumferential direction, the inner side wall of each through groove (21) is continuously drawn in from the inner side wall of the middle pipe (2) to the outer side wall of the middle pipe (2), the inner side wall of the outer pipe (4) is provided with a plurality of clamping grooves (411) matched with the through grooves (21), the inner side wall of each clamping groove (411) is continuously drawn in along the direction of the middle pipe (2) towards the outer pipe (4), the inner side wall of each clamping groove (411) is in smooth transition with the inner side wall of each through groove (21), and clamping blocks (7) matched with the through grooves (21) and the clamping grooves;

the elastic part (35) comprises an annular leaf spring (36) fixedly connected with the sliding sleeve (3), the end part of the middle pipe (2) back to the top connecting joint (1) is in threaded connection with a limiting pipe (5) coaxially arranged with the sleeve, and a limiting groove (51) matched with the annular leaf spring (36) is formed in the inner side wall of the end part of the limiting pipe (5) opposite to the middle pipe (2);

the outer pipe (4) comprises a clamping pipe (41) provided with a clamping groove (411) and a main pipe (42) in threaded connection with the clamping pipe (41), the end part, back to the top connecting joint (1), of the clamping pipe (41) is located inside the main pipe (42), the inner diameter of the clamping pipe (41) inside the main pipe (42) is smaller than that of the main pipe (42), an annular guide ring (53) is fixedly arranged on the outer side wall of the limiting pipe (5), and the outer side wall of the guide ring (53) extends out of the outer side wall of the middle pipe (2) and is abutted to the inner side wall of the outer pipe (4);

when the side wall of fixture block (7) was simultaneously with the inside wall of draw-in groove (411) and the inside wall butt of leading to groove (21), the bottom of top connected node (1) and the top butt of outer tube (4).

2. The gradual release retractor of claim 1, wherein: when the annular leaf spring (36) is abutted against the inside of the limiting groove (51), the annular leaf spring (36) is in a compressed state, and the inner side wall of the abutting groove (32) is abutted against the inner side wall of the limiting pipe (5) at the limiting groove (51).

3. The gradual release retractor of claim 2, wherein: the middle pipe (2) is in threaded connection with a limiting ring (6) on the end part opposite to the top connecting joint (1), and the inner side wall of the limiting ring (6) and the inner side wall of the sliding sleeve (3) opposite to the top connecting joint (1) are located on the same cylindrical surface.

4. The gradual release retractor of claim 3, wherein: the limiting ring (6) is just opposite to the end face of the top connecting joint (1) and is provided with an annular inclined plane part (61), the inclined plane part (61) is arranged towards the center of the inner part of the limiting ring (6), and the annular inclined plane part (61) and the sliding sleeve (3) are coaxially arranged.

5. The gradual release retractor of claim 4, wherein: the limiting pipe (5) is fixedly provided with a thickened pipe (52) arranged along the length direction, and when the annular leaf spring (36) abuts against the inside of the limiting groove (51), the end part of the sliding sleeve (3) opposite to the bottom connecting joint (11) abuts against the end part of the thickened pipe (52) back to the bottom connecting joint (11).

6. The gradual release retractor of claim 5, wherein: the fixture block (7) is in a circular truncated cone shape with the axis vertical to the axis of the middle pipe (2), and one end of the smaller end face of the circular truncated cone-shaped fixture block (7) faces the outer pipe (4).

7. The gradual release retractor of claim 6, wherein: the side wall of the clamping block (7) which is just opposite to the sliding sleeve (3) is in an arc surface shape matched with the outer side wall of the sliding sleeve (3).

8. The gradual release retractor of claim 7, wherein: first sealing washer (8) all have set firmly on well pipe (2) inner wall and sliding sleeve (3) of spacing ring (6) department seted up butt groove (32) department on the lateral wall.