A retractable casing head with anti-leakage function

Abstract

The present invention discloses a retractable and leak-proof casing head, comprising a casing head body, the casing head body comprising an inner cylinder, a positioning connecting tube and a movable outer cylinder, and a first threaded sleeve welded to the bottom of the lower end of the inner cylinder, and a first sealing ring sleeve is provided on the outer side of the upper end and the lower end of the first threaded sleeve, the lower end of the first threaded sleeve is threadedly connected to the inner side of the upper end of the positioning connecting tube, the outer side of the upper end of the inner cylinder is slidably connected to the movable outer cylinder, and an elastic inflatable sleeve is sleeved on the outer side of the inner cylinder between the lower end and the first sealing ring sleeve provided on the upper end. The retractable and leak-proof casing head, in this application, is used in combination with the inner cylinder, the positioning connecting tube and the movable outer cylinder, so that the casing head body is a combined structure, and by moving the movable outer cylinder, the movable outer cylinder moves upward outside the inner cylinder, extending the overall length of the casing head body, thereby meeting the use requirements in different situations and improving the practicality of use.

Description

Technical Field

[0001] The present invention relates to the technical field related to casing heads, and in particular to a retractable casing head with a leakage-proof function. Background Art

[0002] The casing head is used to fix the wellhead of the drilled well, connect the wellhead casing string, support the gravity of the technical casing and the oil layer casing, seal the annular space between the layers of pipes, provide a transition connection for the installation of blowout preventers, tubing heads, and Christmas trees, and through the two side ports on the casing head body, operations such as mud squeezing, monitoring, and adding balancing fluid can be carried out.

[0003] After searching, it was found that the typical casing head in the prior art is such as the publication number CN221896558U, a casing head that is easy to connect, including: a casing head body, the upper end of the casing head body is fixedly installed with a flange, the inner side of the upper end of the casing head body is fixedly installed with a connecting ring, and the inner side of the lower end of the casing head body is fixedly installed with a threaded barrel, and a plurality of limit rods are evenly and elastically connected to the side wall of the casing head body. The limit rod is located below the threaded barrel, and the connecting tube is inserted into the threaded barrel and threadedly connected to the inner wall of the threaded barrel until the upper end of the connecting tube contacts the lower end of the connecting ring, and the upper end of the sealing ring is located in groove 1, so that the connection between the connecting tube and the connecting ring is sealed, and then the threaded cover is screwed. When the threaded cover is moved down, the limit rod can be pushed inward, and the inner end of the limit rod can be inserted into the limit groove by a tension spring to fix the connecting tube to prevent the connecting tube from loosening during use.

[0004] To sum up, the existing casing heads are generally of fixed size when in use and cannot be adjusted for telescopic use, which reduces the practicality of use. In addition, when installed and fixed, the sealing means are relatively simple and dynamic sealing cannot be performed. After long-term use, the seals are prone to aging. If they are not replaced in time, it is easy to cause the sealing performance to deteriorate or even lose the sealing effect. In view of the above problems, the existing equipment needs to be improved. Summary of the Invention

[0005] The object of the present invention is to provide a telescopic and leak-proof cannula head to solve the problem proposed in the above background technology that the existing cannula heads are generally of fixed size structure when in use and cannot be telescopically adjusted, which reduces the practicality of use; and when installed and fixed, the sealing means are relatively simple and dynamic sealing cannot be performed. After long-term use, the seals are prone to aging, and if not replaced in time, it is easy to cause the sealing performance to decline or even lose the sealing effect.

[0006] To achieve the above object, the present invention provides the following technical solution: a telescopic and leak-proof casing head, comprising a casing head body,

[0007] The casing head body includes an inner tube, a positioning connecting tube and a movable outer tube, and a first threaded sleeve is welded to the bottom of the lower end of the inner tube, and a first sealing ring sleeve is provided on the upper end and the outer side of the lower end of the first threaded sleeve. The lower end of the first threaded sleeve is threadedly connected to the inner side of the upper end of the positioning connecting tube, and a first positioning flange is welded on the outer side of the positioning connecting tube. At the same time, a side tube is provided on the rear side of the upper end of the positioning connecting tube. The outer side of the upper end of the inner tube is slidably connected to the movable outer tube, and an elastic inflatable sleeve is sleeved on the outer side of the inner tube between the lower end and the first sealing ring sleeve provided on the upper end of the movable outer tube, and a second positioning flange is provided on the outer side of the movable outer tube.

[0008] A protective mechanism is provided on the outside of the casing head body, and the protective mechanism includes a protective sleeve, a first connecting component, a second connecting component, a first sleeve frame and a second sleeve frame, which is used to protect the outside of the casing head body and extend the service life of the casing head body.

[0009] Preferably, the outer side of the upper end of the inner cylinder is slidably connected to a second threaded sleeve, and the outer side of the lower end of the second threaded sleeve is threadedly connected to the inner side of the upper end of the movable outer cylinder. At the same time, a slide is provided on the outer side of the upper end of the inner cylinder below the second threaded sleeve. The outer side of the slide is symmetrically provided with a slide groove for sliding connection with the inner side of the upper end of the movable outer cylinder, and a sealing filler is filled between the upper end of the slide and the lower end of the second threaded sleeve. At the same time, the lower ends of the two slide grooves are located on the outer side of the inner cylinder and fixedly connected to the limited seat.

[0010] Preferably, the first sealing ring sleeve arranged at the upper end is located between the upper end of the first threaded sleeve and the lower end of the movable outer cylinder, and the first sealing ring sleeve arranged at the lower end is located between the lower end of the first threaded sleeve and the upper end of the positioning connecting pipe.

[0011] Preferably, an inflation tube is provided on one side of the elastic inflatable sleeve, and the inflation tube passes through the lower end of the protective sleeve and is connected to an inflation pump, while the inflation pump is installed on the front side of the first sleeve frame.

[0012] Preferably, grooves are symmetrically provided on the inner side of the lower end of the movable outer cylinder, and guide slide rods are provided in the middle of the two grooves. At the same time, the two guide slide rods are slidably connected to the sliders correspondingly provided on the outer side of the inner cylinder. The bottoms of the two guide slide rods are connected to the upper end of the sealing cover, and the sealing cover is connected to the bottom of the lower end of the movable outer cylinder by installing screws.

[0013] Preferably, the front of the movable outer cylinder is symmetrically provided with delivery pipes outside the position of the sealing filler, and both delivery pipes are provided with pumping pumps, and the lower ends of the two delivery pipes are connected to the storage box provided on the front of the second frame.

[0014] Preferably, the protective sleeve is a rubber bellows, and the lower end of the protective sleeve is connected to the first positioning flange through a first connecting component, and the upper end of the protective sleeve is connected to the second positioning flange through a second connecting component. A first frame is provided on the outer side of the lower end of the protective sleeve and the first connecting component, and a second frame is provided on the outer side of the upper end of the protective sleeve and the second connecting component. At the same time, the top of the threaded vertical rod symmetrically arranged on the upper end of the first frame passes through the second frame and extends to the top of the second frame. The two threaded vertical rods are located on the outer side of the bottom of the second frame and are threadedly connected with positioning nuts. Side panels are symmetrically arranged on both sides of the first frame, and ground nails are provided on both side panels.

[0015] Preferably, the first connecting assembly includes a positioning sleeve, a first sealing gasket and a second sealing gasket, and the positioning sleeve is an I-shaped structure. At the same time, the positioning sleeve is arranged on the outer side of the upper end of the positioning connecting tube, and a first sealing gasket is arranged between the lower end of the positioning sleeve and the upper end of the first positioning flange. The outer side of the lower end of the positioning sleeve is threadedly connected to the first positioning flange through a first fixing bolt arranged at equal intervals, and at the same time, a second sealing gasket is arranged between the upper end of the positioning sleeve and the bottom of the lower end of the protective sleeve, and the outer side of the lower end of the protective sleeve is threadedly connected to the upper end of the positioning connecting tube through a second fixing bolt arranged at equal intervals, which penetrates the second sealing gasket.

[0016] Preferably, the second connecting assembly includes a first sealing block, and the first sealing block is a T-shaped structure. The first sealing block is made of rubber. The outer side of the lower end of the first sealing block is threadedly connected to the inner side of the upper end of the protective sleeve, and the top of the first sealing block is fitted with the lower end of the second positioning flange. At the same time, the third bolts equidistantly arranged on the upper end of the second positioning flange pass through the first sealing block and are threadedly connected to the upper end of the protective sleeve.

[0017] Compared with the prior art, the beneficial effects of the present invention are: the telescopic and leak-proof casing head,

[0018] (1) In order to solve the problem that the existing cannula heads are generally fixed in size and cannot be adjusted telescopically during use, which reduces the practicality of use, the present application provides an inner cylinder, a positioning connecting tube and a movable outer cylinder for use, so that the cannula head body is a combined structure, and by moving the movable outer cylinder, the movable outer cylinder is moved upward outside the inner cylinder, extending the overall length of the cannula head body, thereby meeting the use requirements in different situations and improving the practicality of use;

[0019] (2) In order to solve the problem that the existing casing head has a relatively simple sealing method when it is installed and fixed, and cannot perform dynamic sealing, and the seals are prone to aging after long-term use, and if they are not replaced in time, it is easy to cause the sealing performance to decline or even lose the sealing effect, the present application provides an elastic inflatable sleeve, an inflatable tube and an inflatable pump, as well as a sealing filler, a delivery tube, a pumping pump and a storage box for use, so as to facilitate the protective sealing of the parts of the casing head body that are prone to leakage, and at the same time adjust the sealing area according to the use situation, thereby making the sealing effect of the connection in the casing head body higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the front cross-sectional structure of the present invention;

[0021] Figure 2 This is a schematic diagram of the front view of the casing head body of the present invention;

[0022] Figure 3 This is a schematic diagram of the front cross-sectional structure of the casing head body of the present invention;

[0023] Figure 4 For the present invention Figure 3 A in the middle is an enlarged structural diagram;

[0024] Figure 5 For the present invention Figure 3 The enlarged structural diagram at B in the middle;

[0025] Figure 6 It is a schematic diagram of the front view structure of the present invention;

[0026] Figure 7 It is a rear view structural schematic diagram of the present invention.

[0027] In the figure: 1, casing head body; 101, inner tube; 1011, slider; 1012, slide seat; 102, first threaded sleeve; 103, first sealing ring sleeve; 104, positioning connecting pipe; 1041, side pipe; 105, first positioning flange; 106, elastic inflatable sleeve; 1061, inflatable pipe; 1062, inflatable pump; 107, movable outer tube; 1071, guide slide; 1072, sealing cover; 1073, Slide groove; 1074, limit seat; 108, second positioning flange; 109, second threaded sleeve; 110, sealing packing; 111, delivery pipe; 112, pumping pump; 113, storage box; 2, positioning sleeve; 3, first sealing gasket; 4, second sealing gasket; 5, protective sleeve; 6, first sealing block; 7, first frame; 8, side panel; 9, ground nail; 10, second frame; 11, threaded vertical rod; 12, positioning nut. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1-7 The present invention provides a technical solution: a telescopic casing head with anti-leakage function, according to Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 and Figure 5 As shown, the casing head body 1 includes an inner tube 101, a positioning connecting tube 104 and a movable outer tube 107, and a first threaded sleeve 102 is welded to the bottom of the lower end of the inner tube 101, and a first sealing ring sleeve 103 is provided on the outer side of the upper end and the lower end of the first threaded sleeve 102. The first sealing ring sleeve 103 provided at the upper end is located between the upper end of the first threaded sleeve 102 and the lower end of the movable outer tube 107, and the first sealing ring sleeve 103 provided at the lower end is located between the lower end of the first threaded sleeve 102 and the upper end of the positioning connecting tube 104. By providing the first sealing ring sleeve 103, it is convenient to improve the sealing between the first threaded sleeve 102 and the positioning connecting tube 104 and the elastic inflatable sleeve 106. The lower end of the first threaded sleeve 102 is threadedly connected to the inner side of the upper end of the positioning connecting tube 104, and a first positioning flange 105 is welded to the outer side of the positioning connecting tube 104. At the same time, a side flange 105 is provided on the rear side of the upper end of the positioning connecting tube 104. Tube 1041, by setting side tube 1041, can carry out construction operations such as supplementary squeezing of mud, monitoring and filling of balancing fluid, the outer side of the upper end of the inner tube 101 is slidably connected to the movable outer tube 107, and the outer side of the inner tube 101 is located between the lower end and the upper end of the movable outer tube 107 and is sleeved with an elastic inflatable sleeve 106, an inflation pipe 1061 is provided on one side of the elastic inflatable sleeve 106, and the inflation pipe 1061 passes through the lower end of the protective sleeve 5 and is connected to the inflation pump 1062, and the inflation pump 1062 is installed on the front side of the first sleeve frame 7, and the elastic inflatable sleeve 106 is inflated and deflated through the inflation pipe 1061 by the inflation pump 1062, so that the elastic inflatable sleeve 106 can be adjusted according to the distance between the lower end of the movable outer tube 107 and the first sealing ring sleeve 103, thereby improving the flexibility and sealing of use, and at the same time a second positioning flange 108 is provided on the outer side of the movable outer tube 107.

[0030] The second threaded sleeve 109 is connected to the inner side of the upper end of the inner cylinder 101 through the second threaded sleeve 109, and the outer side of the lower end of the second threaded sleeve 109 is threadedly connected to the inner side of the upper end of the movable outer cylinder 107. The second threaded sleeve 109 is used to seal and guide the connection between the upper end of the movable outer cylinder 107 and the inner cylinder 101 to prevent the movable outer cylinder 107 from deflecting when moving. At the same time, the upper end of the inner cylinder 101 is located below the second threaded sleeve 109 and a slide 1012 is provided on the outer side. The outer side of the slide 1012 is symmetrically provided with a slide groove 1073 on the inner side of the upper end of the movable outer cylinder 107 for sliding connection. The slide 1012 moves inside the slide groove 1073, so that the movable outer cylinder 107 is not easily deflected when moving, thereby improving the stability of movement. A sealing filler 110 is filled between the upper end of the slide 1012 and the lower end of the second threaded sleeve 109. A delivery pipe 111 is symmetrically provided on the outer side of the position of the sealing filler 110 on the front side of the movable outer cylinder 107. 1 is provided with a pumping pump 112, and the lower ends of the two delivery pipes 111 are connected to the storage box 113 set on the front of the second sleeve frame 10. Through one of the pumping pumps 112, it is convenient to transport the sealing filler 110 stored in the storage box 113 through the corresponding delivery pipe 111 to the cavity between the upper end of the slide 1012 and the lower end of the second threaded sleeve 109, which is convenient for the device to fill and seal, thereby improving the sealing during use. At the same time, through another pumping pump 112, it is convenient to transport the sealing filler 110 filled in the cavity between the upper end of the slide 1012 and the lower end of the second threaded sleeve 109 through the corresponding delivery pipe 111 to the storage box 113 for storage, so that the thickness of the sealing filler 110 can be adjusted according to the use situation, thereby improving the flexibility, practicality and sealing of use. At the same time, the lower ends of the two slide grooves 1073 are located on the outside of the inner cylinder 101 and are fixedly connected to the limited seat 1074.

[0031] To further explain, grooves are symmetrically provided on the inner side of the lower end of the movable outer cylinder 107, and a guide slide 1071 is provided in the middle of the two grooves. At the same time, the two guide slides 1071 are slidably connected to the slider 1011 correspondingly provided on the outer side of the inner cylinder 101. The bottom of the two guide slides 1071 is connected to the upper end of the sealing cover 1072, and the sealing cover 1072 is connected to the bottom of the lower end of the movable outer cylinder 107 by installing screws. The slider 1011 moves on the guide slides 1071, so that the extension and contraction movement between the inner cylinder 101 and the movable outer cylinder 107 is relatively smooth.

[0032] according to Figure 1 、 Figure 6 and Figure 7 As shown, a protective mechanism is provided on the outside of the casing head body 1, and the protective mechanism includes a protective sleeve 5, a first connecting component, a second connecting component, a first sleeve frame 7 and a second sleeve frame 10, which are used to protect the outside of the casing head body 1 and extend the service life of the casing head body 1.

[0033] Further explanation, the protective sleeve 5 is a rubber bellows, and the lower end of the protective sleeve 5 is connected to the first positioning flange 105 through a first connecting assembly. The first connecting assembly includes a positioning sleeve 2, a first sealing gasket 3 and a second sealing gasket 4. The positioning sleeve 2 is an I-shaped structure. At the same time, the positioning sleeve 2 is arranged on the outer side of the upper end of the positioning connecting pipe 104. A first sealing gasket 3 is provided between the lower end of the positioning sleeve 2 and the upper end of the first positioning flange 105. The outer side of the lower end of the positioning sleeve 2 is threadedly connected to the first positioning flange 105 through first fixing bolts arranged at equal distances, penetrating the first sealing gasket 3. At the same time, a second sealing gasket 4 is provided between the upper end of the positioning sleeve 2 and the bottom of the lower end of the protective sleeve 5. The outer side of the lower end of the protective sleeve 5 is threadedly connected to the upper end of the positioning connecting pipe 104 through a second fixing bolt arranged at an equal distance. At the same time, the upper end of the protective sleeve 5 is connected to the second positioning flange 108 through a second connecting component. The second connecting component includes a first sealing block 6, and the first sealing block 6 is a T-shaped structure. At the same time, the first sealing block 6 is made of rubber. The outer side of the lower end of the first sealing block 6 is threadedly connected to the inner side of the upper end of the protective sleeve 5, and the top of the first sealing block 6 is connected to the second The lower end of the positioning flange 108 fits together, and the third bolt equidistantly arranged on the upper end of the second positioning flange 108 penetrates the first sealing block 6 and is threadedly connected to the upper end of the protective sleeve 5. The lower end of the protective sleeve 5 is provided with a first frame 7 on the outside of the first connecting component, and the upper end of the protective sleeve 5 is provided with a second frame 10 on the outside of the second connecting component. At the same time, the top of the threaded vertical rod 11 symmetrically arranged on the upper end of the first frame 7 penetrates the second frame 10 and extends to the top of the second frame 10. The two threaded vertical rods 11 are located on the outside of the bottom of the second frame 10 and are threadedly connected to the positioning nut 12. By moving the second The sleeve frame 10 allows the second sleeve frame 10 to move on the threaded vertical rod 11, stretching or folding the protective sleeve 5, and then according to the adjusted position of the second sleeve frame 10, rotate the positioning nut 12 so that the positioning nut 12 fits with the lower end of the second sleeve frame 10, which is convenient for limiting the height of the position of the second sleeve frame 10, improving the practicality of use and the protection of the sleeve head body 1 used synchronously. Side panels 8 are symmetrically provided on both sides of the first sleeve frame 7, and ground nails 9 are provided on both side panels 8. The ground nails 9 are used to facilitate positioning of the protective mechanism and improve the stability of use.

[0034] The directions or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the accompanying drawings. They are merely simplified descriptions for the convenience of describing the present invention, and do not indicate or imply that the devices or elements referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the protection content of the present invention.

[0035] 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 scope of protection of the present invention.

Claims

1. A telescopic and leak-proof casing head, comprising a casing head body (1), characterized in that: The casing head body (1) comprises an inner tube (101), a positioning connecting tube (104) and a movable outer tube (107), and a first threaded sleeve (102) is welded to the bottom of the lower end of the inner tube (101), and a first sealing ring sleeve (103) is provided on the outer side of the upper end and the lower end of the first threaded sleeve (102). The outer side of the upper end of the inner tube (101) is slidably connected to the second threaded sleeve (109), and the outer side of the lower end of the second threaded sleeve (109) is threadedly connected to the inner side of the upper end of the movable outer tube (107). At the same time, a slide seat (1012) is provided on the outer side of the upper end of the inner tube (101) below the second threaded sleeve (109), and a slide groove (1073) is symmetrically provided on the outer side of the slide seat (1012) and the inner side of the upper end of the movable outer tube (107) for sliding connection, and the upper end of the slide seat (1012) is connected to the second threaded sleeve (109). The lower ends of the threaded sleeve (109) are filled with sealing fillers (110), and the lower ends of the two slide grooves (1073) are located outside the inner tube (101) and fixedly connected to the limited seat (1074). The lower end of the first threaded sleeve (102) is threadedly connected to the inner side of the upper end of the positioning connecting tube (104), and the outer side of the positioning connecting tube (104) is welded with a first positioning flange (105). At the same time, a side tube (1041) is provided on the rear side of the upper end of the positioning connecting tube (104). The outer side of the upper end of the inner tube (101) is slidably connected to the movable outer tube (107), and the outer side of the inner tube (101) is sleeved with an elastic inflatable sleeve (106) between the lower end and the first sealing ring sleeve (103) provided at the upper end of the movable outer tube (107), and the outer side of the movable outer tube (107) is provided with a second positioning flange (108). A protective mechanism is provided on the outside of the casing head body (1), and the protective mechanism comprises a protective sleeve (5), a first connecting assembly, a second connecting assembly, a first sleeve frame (7), and a second sleeve frame (10), and is used to protect the outside of the casing head body (1) and extend the service life of the casing head body (1).

2. The retractable and leak-proof cannula head according to claim 1, characterized in that: The first sealing ring sleeve (103) provided at the upper end is located between the upper end of the first threaded sleeve (102) and the lower end of the movable outer cylinder (107), and the first sealing ring sleeve (103) provided at the lower end is located between the lower end of the first threaded sleeve (102) and the upper end of the positioning connecting pipe (104).

3. The retractable and leak-proof cannula head according to claim 1, characterized in that: An inflation tube (1061) is provided on one side of the elastic inflatable sleeve (106), and the inflation tube (1061) passes through the lower end of the protective sleeve (5) and is connected to an inflation pump (1062), while the inflation pump (1062) is installed on the front of the first sleeve frame (7).

4. The retractable and leak-proof cannula head according to claim 1, characterized in that: The inner side of the lower end of the movable outer cylinder (107) is symmetrically provided with grooves, and a guide slide bar (1071) is provided in the middle of the two grooves. The two guide slide bars (1071) are slidably connected to the sliders (1011) correspondingly provided on the outer side of the inner cylinder (101). The bottoms of the two guide slide bars (1071) are connected to the upper end of the sealing cover (1072), and the sealing cover (1072) is connected to the bottom of the lower end of the movable outer cylinder (107) through mounting screws.

5. The retractable and leak-proof cannula head according to claim 1, characterized in that: The front of the movable outer cylinder (107) is symmetrically provided with delivery pipes (111) outside the position of the sealing filler (110), and the two delivery pipes (111) are both provided with a pumping pump (112). At the same time, the lower ends of the two delivery pipes (111) are connected to the storage box (113) provided on the front of the second frame (10).

6. The retractable and leak-proof cannula head according to claim 1, characterized in that: The protective sleeve (5) is a rubber bellows, and the lower end of the protective sleeve (5) is connected to the first positioning flange (105) through a first connecting assembly, and the upper end of the protective sleeve (5) is connected to the second positioning flange (108) through a second connecting assembly. A first sleeve frame (7) is provided between the lower end of the protective sleeve (5) and the outer side of the first connecting assembly, and a second sleeve frame (10) is provided between the upper end of the protective sleeve (5) and the outer side of the second connecting assembly. At the same time, the top of the threaded vertical rod (11) symmetrically provided at the upper end of the first sleeve frame (7) passes through the second sleeve frame (10) and extends to the top of the second sleeve frame (10). The two threaded vertical rods (11) are located on the outer side of the bottom of the second sleeve frame (10) and are both threadedly connected to positioning nuts (12). Side plates (8) are symmetrically provided on both sides of the first sleeve frame (7), and ground nails (9) are provided on both side plates (8).

7. The telescopic and leak-proof cannula head according to claim 1, characterized in that: The first connection assembly comprises a positioning sleeve (2), a first sealing gasket (3) and a second sealing gasket (4), and the positioning sleeve (2) is an I-shaped structure. The positioning sleeve (2) is arranged on the outer side of the upper end of the positioning connection pipe (104). A first sealing gasket (3) is arranged between the lower end of the positioning sleeve (2) and the upper end of the first positioning flange (105). The outer side of the lower end of the positioning sleeve (2) is threadedly connected to the first positioning flange (105) by first fixing bolts arranged at equal intervals and penetrating the first sealing gasket (3). At the same time, a second sealing gasket (4) is arranged between the upper end of the positioning sleeve (2) and the bottom of the lower end of the protective sleeve (5). The outer side of the lower end of the protective sleeve (5) is threadedly connected to the upper end of the positioning connection pipe (104) by second fixing bolts arranged at equal intervals and penetrating the second sealing gasket (4).

8. The retractable and leak-proof cannula head according to claim 1, characterized in that: The second connecting assembly includes a first sealing block (6), and the first sealing block (6) is a T-shaped structure. The first sealing block (6) is made of rubber. The outer side of the lower end of the first sealing block (6) is threadedly connected to the inner side of the upper end of the protective sleeve (5), and the top of the first sealing block (6) is in contact with the lower end of the second positioning flange (108). At the same time, a third bolt equidistantly arranged on the upper end of the second positioning flange (108) passes through the first sealing block (6) and is threadedly connected to the upper end of the protective sleeve (5).

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