Valve sealing structure for natural gas pipeline

Abstract

The invention belongs to the field of hydraulic valves, and particularly relates to a valve sealing structure for a natural gas pipeline, a valve comprises a valve body, a grease injection assembly and a detection assembly are respectively mounted on the valve body, a valve seat is arranged in the valve body, a fluid channel is formed in the valve seat, a valve sleeve is arranged at the upper end of the valve seat, and the peripheral surface of the valve sleeve is matched with the valve body. A plurality of throttling holes are evenly formed in the side, close to the valve seat, of the valve sleeve along the outer circumferential face, a valve element assembly is installed in an inner space formed by the valve sleeve and the valve seat, and the outer circumferential face of the valve element assembly is in sliding fit with the inner circumferential face of the valve sleeve so as to open or close the throttling holes. A composite multi-stage sealing structure is arranged between the valve seat and the valve element assembly and used for sealing a flowing path from the fluid channel to the throttling hole. The sealing structure has better sealing performance, can detect whether the valve leaks or not in time, and carries out emergency sealing on the valve when leakage occurs.

Description

Technical Field

[0001] The present invention belongs to the field of hydraulic valves, and particularly relates to a valve sealing structure for natural gas pipelines. Background Art

[0002] When overhauling natural gas pipelines, corresponding valves are usually set for pipeline venting. In the prior art, the valve seat of the valve sealing structure only has a single soft sealing ring. During long-term use, the sealing ring is prone to wear, corrosion, scratches, etc., which will cause valve leakage. In addition, the valve sealing structure in the prior art cannot timely detect whether the valve has sealing failure, nor can it perform emergency sealing in time when the valve has sealing failure. Summary of the Invention

[0003] To solve the problems existing in the prior art, the purpose of the present invention is to provide a valve sealing structure for natural gas pipelines, which has better sealing performance, can timely detect whether the valve leaks, and can achieve emergency sealing of the valve when leakage occurs, improving the service performance of the valve.

[0004] To achieve the above invention purpose, the present invention provides the following technical solutions: A valve sealing structure for natural gas pipelines, the valve includes a valve body, the sealing structure is installed inside the valve, and the sealing structure at least includes a valve seat, a valve sleeve and a valve core assembly; A valve seat installation groove is provided in the valve body, the valve seat is provided in the valve seat installation groove, a fluid passage is opened in the valve seat, the valve sleeve is provided at the upper end of the valve seat, the outer peripheral surface of the valve sleeve cooperates with the valve body, a plurality of throttle holes are uniformly provided along the outer peripheral surface of the valve sleeve close to the valve seat, and the inner space formed by the valve sleeve and the valve seat is installed with the valve core assembly, and the outer peripheral surface of the valve core assembly is slidably matched with the inner peripheral surface of the valve sleeve to open or close the throttle holes; wherein, A composite multi-stage sealing structure is provided between the valve seat and the valve core assembly, and the composite multi-stage sealing structure is used to seal the flow path flowing from the fluid passage to the throttle holes; A grease injection assembly and a detection assembly are respectively installed on the valve body; the valve core assembly includes a valve core body and a guide sleeve threadedly connected to the valve core body; an annular grease injection groove is opened on the valve core body, a detection pipeline and a grease injection pipeline are respectively opened on the valve seat, the grease injection pipeline is respectively communicated with the grease injection assembly and the annular grease injection groove, and the detection pipeline is communicated with the detection assembly.

[0005] Preferably, the composite multi-stage sealing structure includes: a first sealing portion arranged at the upper end of the valve seat, a second sealing portion and a third sealing portion arranged at the lower end of the valve core assembly, and a main sealing ring and a secondary sealing ring arranged between the valve seat and the third sealing portion; wherein, the third sealing portion and the main sealing ring cooperate with each other to form a first sealing structure, the third sealing portion and the secondary sealing ring cooperate with each other to form a second sealing structure, the first sealing portion and the second sealing portion cooperate with each other to form a third sealing structure, and the first sealing structure, the second sealing structure and the third sealing structure are arranged in sequence along the radial direction of the valve seat.

[0006] Preferably, a mounting boss is provided at the upper end of the valve seat, and the mounting boss cooperates with the valve seat mounting groove. A mounting groove for installing the secondary sealing ring is provided on the mounting boss, and a plurality of water line grooves are provided at the bottom of the mounting groove for installing the secondary sealing ring, and a plurality of barbs are provided on the side wall.

[0007] Preferably, the main sealing ring and the secondary sealing ring are respectively configured as follows: when the valve is in an open state, the axial height difference B between the main sealing ring and the first sealing part is 0.5mm~0.8mm, and the axial height difference A between the secondary sealing ring and the first sealing part is 0.3mm~0.5mm.

[0008] Preferably, a valve core boss is provided at the lower end of the valve core body, the third sealing portion is provided at the bottom of the valve core boss, a first groove is provided on the inner side of the third sealing portion, and the second sealing portion made of cemented carbide is formed in the first groove.

[0009] Preferably, the secondary sealing ring is made of plastic material and has a compression slope on one side; the cross-section of the main sealing ring is triangular and is made of rubber material; when the secondary sealing ring is assembled to the valve seat, one side of the main sealing ring is pressed by the compression slope on the secondary sealing ring, and when the valve is in a closed state, the other side of the main sealing ring is pressed by the compression slope at the lower end of the valve sleeve.

[0010] Preferably, the mounting boss is respectively provided with a first annular channel and a second annular channel, wherein the first annular channel and the second annular channel are not connected to each other; the mounting boss is also provided with a plurality of detection channels and a plurality of grease injection channels, wherein the plurality of detection channels are connected to the first annular channel, and the plurality of grease injection channels are connected to the second annular channel.

[0011] Preferably, an annular grease injection groove is formed on the outer peripheral surface of the valve core boss. A plurality of first channels and a plurality of second channels are respectively formed at the lower end of the valve sleeve. The ends of the plurality of first channels and the plurality of second channels are axially staggered, so that one end of each of the plurality of first channels communicates with a corresponding detection channel, and the other end extends to the outer peripheral surface of the valve core boss and is not communicated with the annular grease injection groove. One end of each of the plurality of second channels communicates with a corresponding grease injection channel, and the other end communicates with the annular grease injection groove.

[0012] Preferably, a third channel communicating with the first annular channel and a fourth channel communicating with the second annular channel are respectively formed on the valve body. The detection assembly is installed on the third channel, and a check valve and a grease injection valve are sequentially installed on the fourth channel.

[0013] Preferably, a sealing groove is further formed on the installation boss, and an annular sealing ring is installed in the sealing groove. The plurality of detection channels are located inside the annular sealing ring, and the plurality of grease injection channels are located outside the annular sealing ring.

[0014] Compared with the prior art, a valve sealing structure for a natural gas pipeline provided by the present invention has the following beneficial technical effects: 1. The valve seat of the conventional valve sealing structure has only one sealing ring. For fluid media with strong permeability, the sealing effect is not good and leakage is likely to occur. In the sealing structure of the present invention, there are two main and auxiliary sealing rings made of different materials and with different structures. The outer main sealing ring is made of rubber and can be prepared from FKM or NBR according to the working conditions. The inner auxiliary sealing ring is made of plastic and can be prepared from PTFE or PEEK according to the working conditions. When one of the main sealing ring or the auxiliary sealing ring is damaged, the other auxiliary sealing ring or main sealing ring can still work independently, extending the service life of the valve.

[0015] 2. Barbs are provided in the installation groove of the present invention. After the auxiliary sealing ring is assembled into the installation groove, the barbs can hold the auxiliary sealing ring to prevent it from being pushed out of the installation groove. At the same time, pressing inclined surfaces are respectively provided on the auxiliary sealing ring and the valve sleeve. After the auxiliary sealing ring is assembled into the installation groove, one side of the main sealing ring is pressed by the pressing inclined surface on the auxiliary sealing ring. When the valve is in the closed state, the other side of the main sealing ring is pressed by the pressing inclined surface at the lower end of the valve sleeve. Through the sealing structure arranged in this way, the main sealing ring and the auxiliary sealing ring can be effectively fixed at the installation position of the valve seat, ensuring stable sealing of the valve.

[0016] 3. The present invention designs a height difference for the valve seat sealing ring, that is, the height of the main sealing ring is set to be greater than the height of the secondary sealing ring, and the height of the secondary sealing ring is greater than the height of the first sealing part. During the closing process of the valve, the valve core assembly first contacts the main sealing ring made of rubber, and at this time, the valve achieves the first-level seal (rubber seal). During the continuous closing process of the valve, the valve core assembly contacts the secondary sealing ring, and at this time, the valve reaches the second-level seal (plastic seal). Continuing to close the valve, the valve core assembly presses the secondary sealing ring downward until it is flush with the first sealing part. At this time, the second sealing part contacts the first sealing part, and the valve reaches the third-level seal (metal seal). By setting a multi-level sealing structure, the sealing performance of the valve is improved.

[0017] 4. The present invention is respectively equipped with a grease injection assembly and a detection assembly on the valve body, and detection channels communicating with the detection assembly are respectively opened on the valve body, valve seat, and valve sleeve. At the same time, grease injection channels communicating with the grease injection assembly are respectively opened on the valve body, valve seat, and valve sleeve. When the detection assembly detects that there is a leakage of fluid medium in the valve, at this time, sealant is injected into the valve through the grease injection assembly, and the sealant is guided to the sealing structure of the valve through the grease injection channels opened in the valve, enabling the emergency sealing of the valve in a timely manner and improving the sealing performance of the valve.

[0018] 5. The present invention sets an annular sealing ring between the mounting boss and the valve sleeve, and several detection channels are located inside the annular sealing ring, while several grease injection channels are located outside the annular sealing ring. When injecting sealant into the valve through the grease injection assembly, on the one hand, the annular sealing ring can prevent the sealant from entering the detection channels through the flow gap, and on the other hand, the sealant can be injected into the annular grease injection groove through the flow gap to seal the gap between the valve core assembly and the valve sleeve, thereby achieving the emergency sealing of the valve. Description of the Drawings

[0019] Figure 1 It is a schematic structural diagram of the valve sealing structure; Figure 2 It is a side view of the valve sealing structure; Figure 3 It is a schematic structural diagram of the valve core body; Figure 4 It is a partially enlarged schematic diagram of the valve sealing structure; Figure 5 It is a partially enlarged schematic diagram of the main and secondary sealing rings when the valve sealing structure is in the open state; Figure 6 It is a schematic structural diagram of the valve seat; Figure 7 It is a top view of the valve seat; Figure 8 It is a partially enlarged schematic diagram of the detection assembly; Figure 9This is a partial enlarged schematic diagram of the grease injection component.

[0020] The meanings of the symbols in the figure are as follows: 1. Valve body; 2. Valve seat; 3. Valve stem; 4. Valve sleeve; 5. Valve core assembly; 6. Grease injection assembly; 7. Detection assembly; 11. Valve seat mounting groove; 12. Third channel; 13. Fourth channel; 21. Mounting boss; 22. First sealing portion; 23. Mounting groove; 24. First annular channel; 25. Second annular channel; 26. Upper mounting surface of valve seat; 27. Lower mounting surface of valve seat; 28. Sealing groove; 29. Fluid channel; 30. Annular sealing ring; 31. Valve stem connection portion; 231, main sealing ring; 232, auxiliary sealing ring; 233, waterline groove; 234, barb; 241, detection channel; 251, grease injection channel; 41. Orifice; 42. First channel; 43. Flow gap; 44. Second channel; 51. Valve core body; 52. Guide sleeve; 511, third sealing portion; 512, second sealing portion; 513, first groove; 514, annular grease injection groove; 515, buffer hole; 516, second groove; 517, valve core boss; 518, cavity; 61. Grease injection valve; 62. Check valve. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0022] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents some embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0023] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features and technical solutions therein may be combined with each other.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper" and "lower" is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the invention product is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. Such terms are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In addition, terms such as "first" and "second" are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0026] See the attached Figure 1 - attached Figure 9 As shown, the present invention provides a valve sealing structure for a natural gas pipeline. The valve includes a valve body 1, and the sealing structure is installed inside the valve. The sealing structure at least includes a valve seat 2, a valve sleeve 4, and a valve core assembly 5.

[0027] A valve seat installation groove 11 is provided in the valve body 1. A valve seat 2 is provided in the valve seat installation groove 11. A fluid passage 29 is opened in the valve seat 2. A valve sleeve 4 is provided at the upper end of the valve seat 2. The outer peripheral surface of the valve sleeve 4 is fitted with the valve body 1. A plurality of throttle holes 41 are uniformly provided on the outer peripheral surface of the valve sleeve 4 close to the valve seat 2. The inner space formed by the valve sleeve 4 and the valve seat 2 is installed with a valve core assembly 5. The outer peripheral surface of the valve core assembly 5 is slidably fitted with the inner peripheral surface of the valve sleeve 4 to open or close the throttle holes. Among them, A composite multi-stage sealing structure is provided between the valve seat 2 and the valve core assembly 5. The composite multi-stage sealing structure is used to seal the flow path flowing from the fluid passage 29 to the throttle holes 41.

[0028] The composite multi-stage sealing structure includes: a first sealing portion 22 provided at the upper end of the valve seat 2, a second sealing portion 512 and a third sealing portion 511 provided at the lower end of the valve core assembly 5, and a main sealing ring 231 and a sub-sealing ring 232 provided between the valve seat 2 and the third sealing portion 511. Among them, the third sealing portion 511 and the main sealing ring 231 cooperate with each other to form a first sealing structure, the third sealing portion 511 and the sub-sealing ring 232 cooperate with each other to form a second sealing structure, and the first sealing portion 22 and the second sealing portion 512 cooperate with each other to form a third sealing structure. The first sealing structure, the second sealing structure, and the third sealing structure are arranged in sequence along the radial direction of the valve seat 2. Among them, both the first sealing portion 22 and the second sealing portion 512 are made of cemented carbide, so that the third sealing structure forms a metal hard sealing structure, and the first sealing structure and the second sealing structure form a composite sealing structure.

[0029] Preferably, the upper end of the valve seat 2 is provided with a mounting boss 21, which engages with the valve seat mounting groove 11. The mounting boss 21 defines a mounting groove 23 for mounting a secondary sealing ring 232. The bottom of the mounting groove 23 is provided with a plurality of waterline grooves 233, and the sidewalls are provided with a plurality of barbs 234. Once the secondary sealing ring 232 is assembled into the mounting groove 23, the barbs 234 retain the secondary sealing ring 232, preventing it from being pushed out of the mounting groove 23. The secondary sealing ring 232 is made of plastic and has a compression slope on one side. The primary sealing ring 231 has a triangular cross-section and is made of rubber. When the secondary sealing ring 232 is assembled to the mounting groove 23, one side of the main sealing ring 231 is pressed by the pressing inclined surface on the secondary sealing ring 232, and when the valve is in the closed state, the other side of the main sealing ring 231 is pressed by the pressing inclined surface at the lower end of the valve sleeve 4, so that the main sealing ring 231 and the secondary sealing ring 232 are fixed in the mounting position of the valve seat 2.

[0030] The main sealing ring 231 and the secondary sealing ring 232 are configured so that, when the valve is open, the axial height difference B between the main sealing ring 231 and the first sealing portion 22 is 0.5mm to 0.8mm, and the axial height difference A between the secondary sealing ring 232 and the first sealing portion 22 is 0.3mm to 0.5mm. As a result, when the valve is closing, the valve core assembly 5 first contacts the rubber main sealing ring 231. Due to the large elastic deformation of the rubber, it deforms significantly, and the valve achieves the first level of sealing (rubber sealing). As the valve continues to close, the valve core assembly 5 contacts the secondary sealing ring 232, and the valve reaches the second level of sealing (plastic sealing). As the valve continues to close, the valve core assembly 5 presses the secondary sealing ring 232 downward until it is flush with the first sealing portion 22. At this point, the second sealing portion 512 contacts the first sealing portion 22, and the valve reaches the third level of sealing (metal sealing).

[0031] Preferably, the mounting boss 21 has an upper valve seat mounting surface 26 and a lower valve seat mounting surface 27. A valve seat sealing ring is disposed between the lower valve seat mounting surface 27 and the valve seat mounting groove 11 to seal between the valve seat 2 and the valve body 1. The thickness of the mounting boss 21 is less than the depth of the valve seat mounting groove 11, so that the lower end of the valve sleeve 4 is located in the valve seat mounting groove 11. Thus, the valve sleeve 4 is securely mounted and positioned using the inner circumferential wall of the valve body 1 and the valve seat mounting groove 11, respectively.

[0032] The valve seat of the conventional valve sealing structure has only one sealing ring. For fluid media with strong permeability, the sealing effect is not good and leakage is likely to occur. In the above embodiment, two main and auxiliary sealing rings with different materials and structures are provided at the sealing structure. The outer main sealing ring is made of rubber and can be selected from FKM and NBR according to the working conditions. The inner auxiliary sealing ring is made of plastic and can be selected from PTFE and PEEK according to the working conditions. In the case where one main sealing ring or auxiliary sealing ring is damaged, the other auxiliary sealing ring or main sealing ring can still work independently, extending the service life of the valve.

[0033] Barbs are provided in the installation groove. After the auxiliary sealing ring is assembled into the installation groove, the barbs can hold the auxiliary sealing ring to prevent it from being pushed out of the installation groove. At the same time, pressing inclined surfaces are respectively provided on the auxiliary sealing ring and the valve sleeve. After the auxiliary sealing ring is assembled into the installation groove, one side of the main sealing ring is pressed by the pressing inclined surface on the auxiliary sealing ring. When the valve is in the closed state, the other side of the main sealing ring is pressed by the pressing inclined surface at the lower end of the valve sleeve. Through the sealing structure arranged in this way, the main sealing ring and the auxiliary sealing ring can be effectively fixed at the installation position of the valve seat, ensuring that the valve achieves stable sealing.

[0034] In addition, a height difference of the valve seat sealing ring is designed in the above embodiment, that is, the height of the main sealing ring is set to be greater than the height of the auxiliary sealing ring, and the height of the auxiliary sealing ring is greater than the height of the first sealing part. During the closing process of the valve, the valve core assembly first contacts the main sealing ring made of rubber, and at this time the valve reaches the first-stage sealing (rubber sealing). During the continuous closing process of the valve, the valve core assembly contacts the auxiliary sealing ring, and at this time the valve reaches the second-stage sealing (plastic sealing). Continuing to close the valve, the valve core assembly presses the auxiliary sealing ring downward until it is flush with the first sealing part. At this time, the second sealing part contacts the first sealing part, and the valve reaches the third-stage sealing (metal sealing). By setting the multi-stage sealing structure, the sealing performance of the valve is improved.

[0035] Preferably, the valve core assembly 5 includes a valve core main body 51 and a guide sleeve 52 threadedly connected to the valve core main body 51. A valve core boss 517 is provided at the lower end of the valve core main body 51. A third sealing part 511 is provided at the bottom of the valve core boss 517. A first groove 513 is formed inside the third sealing part 511, and a second sealing part 512 made of cemented carbide is formed in the first groove 513.

[0036] Preferably, a valve stem connecting portion 31 is formed at the lower end of the valve stem 3, a cavity 518 for inserting the valve stem connecting portion 31 is formed at the upper end of the valve core body 51, a valve stem connecting assembly is arranged in the cavity 518, and after the valve stem connecting portion 31 is inserted into the cavity 518, the valve stem connecting portion 31 is drivingly connected with the valve core body 51 through the valve stem connecting assembly. A second groove 516 for installing the guide sleeve 52 and a buffer hole 515 for communicating the second groove 516 and the cavity 518 are further formed on the valve core body 51. A threaded section is formed on the inner circumferential surface of the second groove 516 so that the valve core body 51 is threadedly connected with the guide sleeve 52. An over-flow channel is formed in the guide sleeve 52, and the fluid medium can enter the cavity 518 through the over-flow channel and the buffer hole 515. The buffer hole can be used to ensure the pressure balance between the upper and lower end faces of the valve core, facilitating the opening and closing of the valve.

[0037] Preferably, a grease injection assembly 6 and a detection assembly 7 are respectively installed on the valve body 1. The grease injection assembly 6 includes a grease injection valve 61 and a check valve 62. An annular grease injection groove 514 is formed on the outer circumferential surface of the valve core boss 517. A detection pipeline and a grease injection pipeline are respectively formed on the valve seat 2. The grease injection pipeline is respectively communicated with the grease injection assembly 6 and the annular grease injection groove 514, and the detection pipeline is communicated with the detection assembly 7. When the detection assembly 7 detects fluid medium leakage in the valve, it indicates that the first-stage seal, the second-stage seal, and the third-stage seal all fail. At this time, sealant is injected into the valve through the grease injection assembly 6, and the sealant reaches the annular grease injection groove 514 through the grease injection pipeline formed in the valve, realizing the emergency seal of the valve.

[0038] Preferably, a first annular channel 24 and a second annular channel 25 are respectively formed on the mounting boss 21, and the first annular channel 24 and the second annular channel 25 are not communicated with each other. A plurality of detection channels 241 and a plurality of grease injection channels 251 are further formed on the mounting boss 21. The plurality of detection channels 241 are communicated with the first annular channel 24, and the plurality of grease injection channels 251 are communicated with the second annular channel 25.

[0039] A plurality of first channels 42 and a plurality of second channels 44 are respectively formed at the lower end of the valve sleeve 4. The ends of the plurality of first channels 42 and the plurality of second channels 44 are axially staggered, so that one end of each of the plurality of first channels 42 is communicated with the corresponding detection channel 241, the other end extends to the outer circumferential surface of the valve core boss 517 and is not communicated with the annular grease injection groove 514, and one end of each of the plurality of second channels 44 is communicated with the corresponding grease injection channel 251, and the other end is communicated with the annular grease injection groove 514.

[0040] A third channel 12 communicated with the first annular channel 24 and a fourth channel 13 communicated with the second annular channel 25 are respectively formed on the valve body 1. A detection assembly 7 is installed on the third channel 12, and a check valve 62 and a grease injection valve 61 are successively installed on the fourth channel 13.

[0041] When the valve experiences seal failure, the fluid medium (such as natural gas) will pass through the gaps between the valve seat 2 and the valve core assembly 5, then through the gaps between the valve core assembly 5 and the valve sleeve 4, then through several first channels 42, then through several detection channels 241, then through the first annular channel 24, and finally through the third channel 12 and be detected by the detection assembly 7, thereby determining the existence of fluid medium leakage, and thus judging that the valve has seal failure. After detecting the seal failure of the valve, sealant is injected into the valve through the grease injection assembly 6. The sealant passes through the grease injection valve 61, the check valve 62, the fourth channel 13, the second annular channel 25, several grease injection channels 251, several second channels 44, and the annular grease injection groove 514, thereby realizing the pressure grease injection of the valve. By guiding the sealant circumferentially into the sealing structure of the valve, the gap between the valve core assembly 5 and the valve sleeve 4 is sealed, realizing the emergency sealing of the valve and improving the sealing performance of the valve.

[0042] In the above embodiment, a grease injection assembly and a detection assembly are respectively installed on the valve body. Detection channels communicating with the detection assembly are respectively opened on the valve body, valve seat and valve sleeve. At the same time, grease injection channels communicating with the grease injection assembly are respectively opened on the valve body, valve seat and valve sleeve. When the detection assembly detects fluid medium leakage in the valve, at this time, sealant is injected into the valve through the grease injection assembly. The sealant is guided to the sealing structure of the valve through the grease injection channels opened in the valve, and the emergency sealing of the valve can be realized in time, improving the sealing performance of the valve.

[0043] Preferably, a sealing groove 28 is also opened on the mounting boss 21. An annular sealing ring 30 is installed in the sealing groove 28. Several detection channels 241 are located inside the annular sealing ring 30, and several grease injection channels 251 are located outside the annular sealing ring 30. When the valve is in the closed state, the lower end of the valve sleeve 4 is sealingly connected to the annular sealing ring 30, and there is a flow gap 43 between the lower end of the valve sleeve 4 and the mounting surface 26 on the valve seat.

[0044] In the above embodiment, by providing an annular sealing ring between the mounting boss and the valve sleeve, and several detection channels are located inside the annular sealing ring, and several grease injection channels are located outside the annular sealing ring. When injecting sealant into the valve through the grease injection assembly, on the one hand, the annular sealing ring can prevent the sealant from entering the detection channels through the flow gap, and on the other hand, the sealant can be injected into the annular grease injection groove through the flow gap to seal the gap between the valve core assembly and the valve sleeve, thereby realizing the emergency sealing of the valve.

[0045] The above embodiments are only used to illustrate the present invention and do not limit the technical solutions described in the present invention. Although this specification has described the present invention in detail with reference to the above various embodiments, the present invention is not limited to the above specific embodiments. Therefore, any modification or equivalent replacement of the present invention; and all technical solutions and their improvements that do not depart from the spirit and scope of the invention are covered by the scope of the claims of the present invention.

Claims

1. A valve sealing structure for a natural gas pipeline, characterized in that: The valve includes a valve body, and the sealing structure is installed inside the valve. The sealing structure at least includes a valve seat, a valve sleeve, and a spool assembly; A valve seat installation groove is provided in the valve body. The valve seat is provided in the valve seat installation groove. A fluid passage is provided in the valve seat. The valve sleeve is provided at the upper end of the valve seat. The outer peripheral surface of the valve sleeve cooperates with the valve body. A plurality of throttle holes are evenly provided on the outer peripheral surface of the valve sleeve close to the valve seat. The inner space formed by the valve sleeve and the valve seat is installed with the spool assembly. The outer peripheral surface of the spool assembly slides with the inner peripheral surface of the valve sleeve to open or close the throttle holes; wherein, A composite multi-stage sealing structure is provided between the valve seat and the spool assembly, and this composite multi-stage sealing structure is used to seal the flow path flowing from the fluid passage to the throttle holes; A grease injection assembly and a detection assembly are respectively installed on the valve body. The spool assembly includes a spool body and a guide sleeve threadedly connected to the spool body; an annular grease injection groove is provided on the spool body. A detection pipeline and a grease injection pipeline are respectively provided on the valve seat. The grease injection pipeline is respectively communicated with the grease injection assembly and the annular grease injection groove, and the detection pipeline is communicated with the detection assembly.

2. The valve sealing structure according to claim 1, wherein: The composite multi-stage sealing structure includes: a first sealing portion provided at the upper end of the valve seat, a second sealing portion and a third sealing portion provided at the lower end of the spool assembly, and a main sealing ring and a secondary sealing ring provided between the valve seat and the third sealing portion; wherein, the third sealing portion and the main sealing ring cooperate with each other to form a first sealing structure, the third sealing portion and the secondary sealing ring cooperate with each other to form a second sealing structure, the first sealing portion and the second sealing portion cooperate with each other to form a third sealing structure, and the first sealing structure, the second sealing structure, and the third sealing structure are sequentially arranged along the radial direction of the valve seat.

3. The valve sealing structure according to claim 2, characterized in that: An installation boss is provided at the upper end of the valve seat. The installation boss cooperates with the valve seat installation groove. An installation groove for installing the secondary sealing ring is provided on the installation boss. A plurality of water ripple convex grooves are provided at the bottom of the installation groove for installing the secondary sealing ring, and a plurality of barbs are provided on the side wall.

4. The valve sealing structure according to claim 3, wherein: The main sealing ring and the secondary sealing ring are respectively set as: when the valve is in the open state, the height difference B in the axial direction between the main sealing ring and the first sealing portion is 0.5 mm to 0.8 mm, and the height difference A in the axial direction between the secondary sealing ring and the first sealing portion is 0.3 mm to 0.5 mm.

5. The valve sealing structure according to claim 4, characterized in that: A spool boss is provided at the lower end of the spool body. The third sealing portion is provided at the bottom of the spool boss. A first groove is provided inside the third sealing portion, and the second sealing portion made of cemented carbide material is formed in the first groove.

6. The valve sealing structure according to claim 5, wherein: The secondary sealing ring is made of plastic material and has a pressing inclined surface on one side; the cross section of the main sealing ring is triangular and is made of rubber material; when the secondary sealing ring is assembled to the valve seat, one side of the main sealing ring is pressed by the pressing inclined surface on the secondary sealing ring, and when the valve is in the closed state, the other side of the main sealing ring is pressed by the pressing inclined surface at the lower end of the valve sleeve.

7. The valve sealing structure according to claim 6, characterized in that: The mounting bosses are respectively provided with a first annular channel and a second annular channel, wherein the first annular channel and the second annular channel are not connected to each other; the mounting bosses are further provided with a plurality of detection channels and a plurality of grease injection channels, and the plurality of detection channels are communicated with the first annular channel, and the plurality of grease injection channels are communicated with the second annular channel.

8. The valve sealing structure according to claim 7, wherein: An annular grease injection groove is formed on the outer peripheral surface of the valve core boss, and a plurality of first channels and a plurality of second channels are respectively formed at the lower end of the valve sleeve. The ends of the plurality of first channels and the plurality of second channels are axially staggered, so that one end of the plurality of first channels is communicated with the corresponding detection channel, and the other end extends to the outer peripheral surface of the valve core boss and is not communicated with the annular grease injection groove. One end of the plurality of second channels is communicated with the corresponding grease injection channel, and the other end is communicated with the annular grease injection groove.

9. The valve sealing structure according to claim 8, characterized in that: A third channel communicated with the first annular channel and a fourth channel communicated with the second annular channel are respectively formed on the valve body. A detection component is installed on the third channel, and a check valve and a grease injection valve are sequentially installed on the fourth channel.

10. The valve sealing structure according to claim 9, wherein: A sealing groove is further formed on the mounting boss, and an annular sealing ring is installed in the sealing groove. The plurality of detection channels are located inside the annular sealing ring, and the plurality of grease injection channels are located outside the annular sealing ring.

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