Thread sealing structure

Abstract

The invention relates to the technical field of sealing, in particular to a thread sealing structure which comprises an internal thread connector, an external thread connector in threaded connection fit with the internal thread connector and a sealing ring, and a groove extending in the circumferential direction of the internal thread face or the external thread face of the external thread connector is formed in the internal thread face of the internal thread connector or the external thread face of the external thread connector. The groove is used for accommodating the sealing ring; when the groove is formed in the internal thread surface, internal threads matched with the threads on the external thread surface are arranged on the sealing ring; when the groove is formed in the external thread face, external threads matched with the threads on the internal thread face are arranged on the sealing ring. According to the technical scheme, the groove for containing the sealing ring is formed in one of the internal thread face of the internal thread connector and the external thread face of the external thread connector, and the threads are arranged on the sealing ring, so that the long-term sealing reliability of the thread sealing structure is improved.

Description

Technical Field

[0001] The invention relates to the technical field of sealing, in particular to a thread sealing structure. Background Art

[0002] In various industrial equipment and systems, threaded sealing structure is a common sealing method, which is widely used in water system pipelines, valves, pumps and other equipment. The main function of the threaded sealing structure is to prevent fluid or gas leakage from the pipeline connection to ensure the normal operation of the equipment. In practical applications, threaded sealing structures usually adopt sealing ring end face or radial sealing, threaded sealant sealing, raw tape sealing and other methods to achieve sealing. Among them, threaded sealant sealing can provide long-term and stable sealing effect, but it may react with the internal medium of the system, or overflow during use, affecting the medium in the pipeline.

[0003] In the process of implementing this application, the inventors found that there are at least the following problems in the prior art:

[0004] Although sealing rings and raw tape seals will not react with the internal media of the system, their long-term reliability is insufficient. After long-term use, the sealing effect may be reduced due to aging and other problems. Summary of the invention

[0005] The present application proposes a thread sealing structure, aiming to improve the long-term sealing reliability of a sealing ring type thread sealing structure.

[0006] In a first aspect, an embodiment of the present application provides a threaded sealing structure, comprising an internal threaded joint, an external threaded joint threadedly matched with the internal threaded joint, and a sealing ring, wherein the internal thread surface of the internal threaded joint or the external thread surface of the external threaded joint is formed with a groove extending along its circumference, and the groove is used to accommodate the sealing ring;

[0007] When the groove is provided on the internal thread surface, the sealing ring is provided with an internal thread matching the thread on the external thread surface;

[0008] When the groove is arranged on the external thread surface, the sealing ring is provided with an external thread matching with the thread on the internal thread surface.

[0009] In some embodiments, the groove is provided on the external thread surface, the inner diameter of the groove is d2, the inner diameter of the sealing ring in a natural state is d1, d1≤d2; and / or,

[0010] The axial width of the groove is W, the axial thickness of the sealing ring in the natural state is H, H≥W; and / or,

[0011] The pitch on the external thread surface is P, H≥P.

[0012] In some embodiments, the sealing ring is disposed in the groove, the sealing ring is sleeved on the external thread joint, the major diameter of the thread on the external thread surface is D1, the major diameter of the external thread of the sealing ring is D2, and D2>D1.

[0013] In some embodiments, 0.1 mm ≤ D2 - D1 ≤ 0.3 mm; and / or,

[0014] 3mm≤d2-d1≤6mm; and / or,

[0015] The minor diameter of the external thread of the sealing ring is d3, the minor diameter of the thread on the external thread surface is d4, and 0.1mm≤d3-d4≤0.2mm.

[0016] In some embodiments, there is a gap between a side of the external thread on the sealing ring facing the groove and the groove.

[0017] In some embodiments, the axial cross-sectional area of ​​the groove is S1, the axial cross-sectional area of ​​the sealing ring is S2, and S2 = (85% to 95%) S1.

[0018] In some embodiments, the groove is arranged on the external thread surface, the external thread joint has a head and a tail, the internal thread joint is screwed from the head to the tail, and the groove is arranged on one end of the external thread surface close to the head.

[0019] In some embodiments, the external thread surface has n turns of threads between the groove and the head end of the external thread joint, where 1≤n≤3.

[0020] In some embodiments, the external threaded joint, the sealing ring and the internal threaded joint are sequentially sleeved from the inside to the outside, the sealing ring is arranged in the groove, the internal threaded joint is threadedly connected with the external threaded joint and the sealing ring, and the external thread on the sealing ring is clamped between the thread on the internal thread surface and the thread on the external thread surface.

[0021] In some embodiments, a sealant is disposed between the external thread surface and the internal thread surface, and the sealant is disposed on a side of the groove away from the head.

[0022] Compared with the prior art, this technical solution has at least the following technical effects:

[0023] The technical solution of the present application improves the long-term sealing reliability of the threaded sealing structure by providing a groove for accommodating a sealing ring on one of the internal thread surface of the internal thread joint or the external thread surface of the external thread joint, and providing a thread on the sealing ring. During the assembly process of the threaded sealing structure, the sealing ring is first inserted into the groove, and the sealing ring is assembled into a whole with one of the external thread joint or the internal thread joint before being screwed with the other. During the screwing process, the threads on the external thread joint or the internal thread joint will mesh with the threads on the sealing ring, and as the internal thread joint continues to be screwed in along the threads on the surface of the external thread joint, the sealing ring will be further compressed. This compression method ensures the close contact between the sealing ring and the internal thread joint and the external thread joint, and can ensure the reliability of the sealing ring during use, thereby improving the long-term sealing reliability of the threaded sealing structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0025] Figure 1 This is a schematic structural diagram of a threaded sealing structure according to an embodiment of the present application;

[0026] Figure 2 for Figure 1 A top view of the middle thread sealing structure in an assembled state;

[0027] Figure 3 for Figure 2 AA section view;

[0028] Figure 4 for Figure 3 Exploded diagram of

[0029] Figure 5 for Figure 2 Schematic diagram of the structure of the Chinese and foreign threaded joint;

[0030] Figure 6 for Figure 2 Schematic diagram of the structure of the middle sealing ring.

[0031] Reference numerals:

[0032] 100 Thread seal structure 110 Internal thread connector 111 Internal thread surface 120 Male thread connector 121 External thread surface 121a Grooves 121b Sealant coating area 1221 head 1222 Tail 130 Sealing ring DETAILED DESCRIPTION

[0033] In order to better understand the technical solution of the present invention, the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0034] It should be clear that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0036] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0037] The present application provides a thread sealing structure 100 .

[0038] See also Figure 1-Figure 6 In an embodiment of the present application, the threaded sealing structure 100 includes an internal threaded joint 110, an external threaded joint 120 threadedly connected to the internal threaded joint 110, and a sealing ring 130. The internal thread surface 111 of the internal threaded joint 110 or the external thread surface 121 of the external threaded joint 120 is formed with a groove 121a extending along its circumferential direction, and the groove 121a is used to accommodate the sealing ring 130; when the groove 121a is set on the internal thread surface 111 of the internal threaded joint 110, the sealing ring 130 is provided with an internal thread that matches the thread on the external thread surface 121 of the external threaded joint 120; when the groove 121a is set on the external thread surface 121 of the external threaded joint 120, the sealing ring 130 is provided with an external thread that matches the thread on the internal thread surface 111 of the internal threaded joint 110.

[0039] Specifically, the internal thread surface 111 is arranged on the inner wall of the internal thread joint 110, and the external thread surface 121 is arranged on the outer wall of the external thread joint 120. The internal thread surface 111 and the external thread surface 121 are both provided with multiple turns of threads. When the threaded sealing structure 100 is in an assembled state, the external thread joint 120, the sealing ring 130 and the internal thread joint 110 are sequentially sleeved from the inside to the outside, and the internal thread surface 111 is meshed with the external thread surface 121, and the threads on the sealing ring 130 are meshed with the threads on the internal thread surface 111 or the external thread surface 121.

[0040] The technical solution of the present application improves the long-term sealing reliability of the threaded sealing structure 100 by providing a groove 121a for accommodating the sealing ring 130 on one of the internal thread surface 111 of the internal threaded joint 110 or the external thread surface 121 of the external threaded joint 120, and providing threads on the sealing ring 130. During the assembly process of the threaded sealing structure 100, the sealing ring 130 is first inserted into the groove 121a, and the sealing ring 130 is assembled into a whole with one of the external threaded joint 120 or the internal threaded joint 110 and then threadedly connected with the other. During the threaded connection process, the threads on the external threaded joint 120 or the internal threaded joint 110 will engage with the threads on the sealing ring 130, and as the internal threaded joint 110 continues to be screwed in along the surface threads of the external threaded joint 120, the sealing ring 130 will be further compressed. This compression method ensures the close contact between the sealing ring 130 and the internal threaded joint 110 and the external threaded joint 120, which can ensure the reliability of the sealing ring 130 during use, thereby improving the long-term sealing reliability of the threaded sealing structure 100.

[0041] See also Figure 3 and Figure 4 In the embodiment of the present application, the internal threaded joint 110 has a front end and a rear end, and the external threaded joint 120 has a head 1221 and a tail 1222. During the assembly process of the threaded sealing structure 100, the front end of the internal threaded joint 110 is screwed from the head 1221 of the external threaded joint 120 toward the tail 1222; when the threaded sealing structure 100 is in an assembled state, the sealing ring 130 is sandwiched between the rear end of the internal threaded joint 110 and the head 1221 of the external threaded joint 120, and the sealing ring 130 is threadedly connected to the rear end of the internal threaded joint 110 or the head 1221 of the external threaded joint 120.

[0042] Please continue reading Figure 3 In the embodiment of the present application, in order to further improve the long-term sealing reliability of the threaded sealing structure 100, a sealant is provided between the external thread surface 121 and the internal thread surface 111. Specifically, a sealant coating area 121b is formed between the external thread surface 121 and the internal thread surface 111, and the sealant coating area 121b is located on the side of the groove 121a facing away from the head 1221. Before the internal thread joint 110 is screwed into the head 1221 of the external thread joint 120, the sealant is first applied to the sealant coating area 121b of the external thread surface 121. Subsequently, the sealant will slowly solidify and can seal the gap between the external thread surface 121 and the internal thread surface 111 corresponding to the sealant coating area 121b.

[0043] Sealant can provide a long-term and stable sealing effect, but in the prior art, the sealant sealing method has the following problems: since it takes a certain amount of time for the sealant to cure, in the initial use of the threaded sealing structure, the sealant may react with the medium inside the pipe connected to the threaded sealing structure, or the sealant may overflow during use, thereby affecting the medium inside the pipe. If the overflowing sealant reacts with the medium in the pipe to produce flocs, it will also cause blockage of the pipe.

[0044] In the embodiment of the present application, by combining the sealant sealing method with the sealing ring sealing method, the problems existing in the sealant sealing method mentioned above can be solved. In the technical solution of the present application, during the use of the threaded sealing structure 100, the medium in the pipeline passes through the two sealing lines of the threaded sealing structure 100: the first sealing line - the sealing ring 130, and the second sealing line - the sealant; in the early stage of the use of the threaded sealing structure 100, the sealing ring 130 has excellent sealing performance, which makes it difficult for the medium in the pipeline to cross the first sealing line of the threaded sealing structure 100 and contact the sealant, and the uncured sealant cannot cross the sealing ring 130 and contact the medium in the pipeline; as the use time of the threaded sealing structure 100 increases, the sealing effect of the sealing ring 130 will gradually decrease, and the first sealing line will not be able to completely block the medium, but when the medium in the pipeline breaks through the first sealing line, it will be blocked by the second sealing line - the sealant, because the sealant has been completely cured at this time, it will not react with the medium.

[0045] In addition, the sealant also has a good shock-absorbing effect. The present application combines the sealant sealing method with the sealing method of the sealing ring 130, which is also helpful in solving the problem of reduced sealing performance of the sealing ring 130 caused by vibration.

[0046] In the embodiment of the present application, preferably, the groove 121a is arranged on the external thread surface 121 of the external thread joint 120. This arrangement is more convenient for assembling the sealing ring 130 and the thread joint, and can also improve the assembly stability of the sealing ring 130 and the thread joint.

[0047] The following further describes the embodiment of the present application by taking the groove 121 a disposed on the external thread surface 121 of the external thread joint 120 as an example.

[0048] See also Figure 5 and Figure 6In the embodiment of the present application, the inner diameter of the groove 121a is d2, and the inner diameter of the sealing ring 130 in the natural state is d1, d1≤d2. This arrangement is conducive to improving the tightness of the sealing ring 130 and the external threaded joint 120 in the assembled state, and can prevent the sealing ring 130 from being separated from the groove 121a during the subsequent engagement with the internal threaded joint 110. It can be understood that if the groove 121a is set on the internal thread surface 111 of the internal threaded joint 110, then d1≥d2.

[0049] In the embodiment of the present application, preferably, d1<d2. In some specific embodiments, 3mm≤d2-d1≤6mm. Within this difference range, it is convenient to assemble the sealing ring 130 with the external threaded joint 120, and it can ensure that the sealing ring 130 can be tightly sleeved on the external threaded joint 120 in the assembled state. If the difference between d2 and d1 is too large, it will increase the difficulty of installing the sealing ring 130 into the groove 121a of the external threaded joint 120. The larger the difference between d2 and d1, the tighter the sleeve of the sealing ring 130 and the external threaded joint 120 in the assembled state, and the more difficult it is for the sealing ring 130 to detach from the groove 121a; but correspondingly, the larger the difference between d2 and d1, the greater the difficulty of assembling the sealing ring 130 and the external threaded joint 120.

[0050] See also Figure 5 and Figure 6 In the embodiment of the present application, the axial width of the groove 121a is W, and the axial thickness of the sealing ring 130 in the natural state is H, H≤W. This arrangement is conducive to the assembly of the sealing ring 130 and the external threaded joint 120, and can prevent the sealing ring 130 from being compressed in advance.

[0051] Preferably, WH≤0.1 mm. If the difference between H and W is too large, it is not conducive to improving the assembly stability of the sealing ring 130 and the external threaded joint 120, and it is not conducive to ensuring that the threads on the internal threaded joint 110 and the threads on the sealing ring 130 are fully engaged in the subsequent assembly process.

[0052] In the embodiment of the present application, the pitch on the external thread surface 121 is P, and H≥P.

[0053] Specifically, m teeth grooves are formed on the sealing ring 130 to match the threads on the internal threaded joint 110, H=m*P, where m is a positive integer and P is the pitch on the external thread surface 121 or the internal thread surface 111. By setting H=m*P, the threads on the external threaded joint 120 and the threads on the sealing ring 130 can be well connected, which facilitates the smooth screwing of the internal threaded joint 110 on the external threaded joint 120 during the assembly process, and is conducive to the full engagement of the internal threaded joint 110 with the external threaded joint 120 and the sealing ring 130.

[0054] In the embodiment of the present application, the greater the value of m, the greater the degree of engagement between the sealing ring 130 and the internal threaded joint 110, the greater the filling range of the sealing ring 130 between the internal threaded joint 110 and the external threaded joint 120, and the more conducive to improving the long-term sealing stability of the threaded sealing structure 100. However, correspondingly, the increase in the value of m will also increase the difficulty of processing the sealing ring 130, thereby increasing the production cost of the threaded sealing structure 100. Generally, when m=1, the long-term sealing stability of the threaded sealing structure 100 can already meet the application requirements.

[0055] In the embodiment of the present application, the depth and width of the groove 121a can be adjusted according to the radial thickness and axial width W of the sealing ring 130, respectively, and the embodiment of the present application does not specifically limit this. In a specific embodiment, the depth and width of the groove 121a are 1 mm and 2 mm.

[0056] See also Figure 5 and Figure 6 In the embodiment of the present application, when the sealing ring 130 is assembled with the external threaded joint 120 (not assembled with the internal threaded joint 110), the sealing ring 130 is arranged in the groove 121a, and the sealing ring 130 is sleeved on the external threaded joint 120. The major diameter of the thread on the external thread surface 121 is D1, and the major diameter of the external thread on the sealing ring 130 is D2, and D2>D1. During the assembly process of the external threaded joint 120 (sleeved with the sealing ring 130) and the internal threaded joint 110, when the internal threaded joint 110 and the sealing ring 130 are initially engaged, the threads on the sealing ring 130 can be radially compressed, and the threads on the sealing ring 130 wrap the side of the threads on the thread surface. In the subsequent screwing process of the internal threaded connection, the sealing ring 130 extends along the thread direction to increase the wrapping force of the threads on the internal thread surface 111, and further improves the sealing effect of the sealing ring 130. It can be understood that if the groove 121 a is disposed on the internal thread surface 111 of the internal thread joint 110 , the internal thread minor diameter on the sealing ring 130 is smaller than the thread minor diameter on the internal thread surface 111 .

[0057] In the embodiment of the present application, preferably, 0.1mm≤D2-D1≤0.3mm. If the difference between D2 and D1 is too large, it will be detrimental to the assembly of the internal threaded joint 110 and the external threaded joint 120 (with a sealing ring 130); if the difference between D2 and D1 is too small, the compression amount of the sealing ring 130 in the assembled state cannot meet the sealing requirements. By limiting the difference between D2 and D1 within the above range, the present application can ensure that the compression amount of the sealing ring 130 in the assembled state can meet the sealing requirements, and also takes into account the convenience of assembly of the internal threaded joint 110 and the external threaded joint 120 (with a sealing ring 130).

[0058] See also Figure 5 and Figure 6 In the embodiment of the present application, when the sealing ring 130 is assembled with the external threaded joint 120 (not assembled with the internal threaded joint 110), the external thread minor diameter of the sealing ring 130 is d3, and the thread minor diameter on the external thread surface 121 of the external threaded joint 120 is d4, and 0.1mm≤d3-d4≤0.2mm. The greater the difference between d3 and d4, the greater the compression of the sealing ring 130 in the assembled state of the threaded sealing structure 100, which is more conducive to improving the overall sealing performance of the threaded sealing structure 100. However, when d3-d4>0.2mm, the sealing ring 130 may be over-compressed, thereby affecting the overall stability of the threaded sealing structure 100.

[0059] In the embodiment of the present application, when the sealing ring 130 is assembled with the external threaded joint 120 (not assembled with the internal threaded joint 110), there is a gap between the side of the thread on the sealing ring 130 facing the groove 121a and the groove 121a. Specifically, the side of the thread on the sealing ring 130 facing the groove 121a is an inclined surface, and during the assembly process of the external threaded joint 120 (with the sealing ring 130) and the internal threaded joint 110, the internal threaded joint 110 will squeeze the sealing ring 130 toward the groove wall of the groove 121a, and the gap between the thread on the sealing ring 130 and the groove 121a provides a space for accommodating the squeezed sealing ring 130.

[0060] See also Figure 5 and Figure 6 In the embodiment of the present application, the axial cross-sectional area of ​​the groove 121a is S1, and the axial cross-sectional area of ​​the sealing ring 130 is S2, S2 = (85% ~ 95%) S1, specifically, S2 = 85% S1, 90% S1, 95% S1 or any value therebetween. The ratio of S2 to S1 reflects the space proportion of the sealing ring 130 in the groove 121a. The larger the ratio, the larger the space proportion of the sealing ring 130 in the groove 121a, and the smaller the space reserved by the groove 121a for accommodating the deformation of the sealing ring 130; if the ratio is too large, the space reserved by the groove 121a for accommodating the deformation of the sealing ring 130 is too small, which may easily lead to excessive compression of the sealing ring 130; if the ratio is too small, the space reserved by the groove 121a for accommodating the deformation of the sealing ring 130 is too large, which will reduce the compression ratio of the sealing ring 130 and affect the sealing effect of the sealing ring 130.

[0061] See also Figure 5In the embodiment of the present application, further, the external thread surface 121 has n threads between the groove 121a and the head 1221 end of the external thread joint 120, 1≤n≤3. This arrangement facilitates the internal thread joint 110 to be screwed in from the head 1221 end of the external thread joint 120 when the internal thread joint 110 and the external thread joint 120 (with a sealing ring 130) are assembled. If the value of n is too large, it also means that the farther the groove 121a is set from the head 1221 end of the external thread joint 120 and the closer the tail 1222 end is, the shorter the meshing time of the internal thread joint 110 and the sealing ring 130 is during the assembly process of the internal thread joint 110 and the external thread joint 120 (with a sealing ring 130), the smaller the degree of extrusion of the sealing ring 130 is, and the less conducive it is to improve the overall sealing performance of the threaded sealing structure 100.

[0062] In the embodiment of the present application, the sealing ring 130 is an elastic member, and its material can be adjusted according to the specific application environment. In different application scenarios, the requirements for the corrosion resistance, high temperature resistance, high pressure resistance and other characteristics of the sealing ring 130 are different. Therefore, the embodiment of the present application does not specifically limit this. As an example, the material of the sealing ring 130 can be EPDM rubber, polytetrafluoroethylene, etc. Based on cost considerations, preferably, the material of the sealing ring 130 is EPDM rubber.

[0063] In the embodiment of the present application, the groove 121a is annular, and specifically may be a circular ring, a polygonal ring, or a ring of other shapes, which is not particularly limited in the embodiment of the present application.

[0064] Correspondingly, the sealing ring 130 is also annular, and the shape of the inner ring of the sealing ring 130 is consistent with the shape of the groove 121a.

[0065] In a preferred embodiment, in order to facilitate inserting the sealing ring 130 into the groove 121 a, the groove 121 a and the sealing ring 130 are both designed to be circular rings.

[0066] It can be understood that in different application scenarios, there are differences in parameters such as the outer aperture / major thread diameter / minor thread diameter of the internal threaded joint 110, the inner aperture / major thread diameter / minor thread diameter of the threaded joint, the depth / axial width W of the groove 121a, and the inner diameter d1 / axial thickness H of the sealing ring 130. Those skilled in the art can make corresponding adjustments based on the actual application scenarios, and this application does not specifically limit this.

[0067] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. 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 thread sealing structure, characterized in that: It comprises an internal thread joint, an external thread joint threadedly matched with the internal thread joint, and a sealing ring, wherein the internal thread surface of the internal thread joint or the external thread surface of the external thread joint is formed with a groove extending along the circumference thereof, and the groove is used to accommodate the sealing ring; When the groove is provided on the internal thread surface, the sealing ring is provided with an internal thread matching the thread on the external thread surface; When the groove is arranged on the external thread surface, the sealing ring is provided with an external thread matching with the thread on the internal thread surface.

2. The threaded sealing structure according to claim 1, characterized in that: The groove is arranged on the external thread surface, the inner diameter of the groove is d2, the inner diameter of the sealing ring in a natural state is d1, d1≤d2; and / or, The axial width of the groove is W, and the axial thickness of the sealing ring in the natural state is H, H≤W; and / or, The pitch on the external thread surface is P, H≥P.

3. The threaded sealing structure according to claim 2, characterized in that: The sealing ring is arranged in the groove, and the sealing ring is sleeved on the external thread joint. The major diameter of the thread on the external thread surface is D1, and the major diameter of the external thread of the sealing ring is D2, and D2>D1.

4. The threaded sealing structure according to claim 3, characterized in that: 0.1mm≤D2-D1≤0.3mm; and / or, 3mm≤d2-d1≤6mm; and / or, The minor diameter of the external thread of the sealing ring is d3, the minor diameter of the thread on the external thread surface is d4, and 0.1mm≤d3-d4≤0.2mm.

5. The threaded sealing structure according to claim 2, characterized in that: There is a gap between the side of the external thread on the sealing ring facing the groove and the groove.

6. The threaded sealing structure according to claim 1, characterized in that: The axial cross-sectional area of ​​the groove is S1, and the axial cross-sectional area of ​​the sealing ring is S2, where S2 = (85% to 95%) S1.

7. The threaded sealing structure according to claim 1, characterized in that: The groove is arranged on the external thread surface, the external thread joint has a head and a tail, the internal thread joint is screwed from the head to the tail, and the groove is arranged on one end of the external thread surface close to the head.

8. The threaded sealing structure according to claim 7, characterized in that: The external thread surface is provided with n turns of thread between the groove and the head end of the external thread joint, where 1≤n≤3.

9. The threaded sealing structure according to claim 7, characterized in that: The external thread joint, the sealing ring and the internal thread joint are sequentially sleeved from the inside to the outside, the sealing ring is arranged in the groove, the internal thread joint is threadedly connected with the external thread joint and the sealing ring, and the external thread on the sealing ring is clamped between the thread on the internal thread surface and the thread on the external thread surface.

10. The threaded sealing structure according to claim 9, characterized in that: A sealant is arranged between the external thread surface and the internal thread surface, and the sealant is arranged on a side of the groove away from the head.

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