Low torque globe valve

Abstract

The present invention discloses a low-torque globe valve, which includes a valve body, a valve cover, a valve stem, a valve flap and a valve seat. The valve flap is installed at the inner end of the valve stem. A first flow channel and a second flow channel are provided in the valve body. An overflow port is provided between the first flow channel and the second flow channel. The valve seat is installed on the overflow port. A first conical sealing surface is provided on the valve seat, and a second conical sealing surface that cooperates with the first conical sealing surface is provided on the valve flap. A plurality of slow-closing components are installed on the valve seat. A plurality of guide holes are opened on the inner wall of the valve seat, and a plurality of first pressure relief holes are opened on the valve seat. The slow-closing components are installed in the corresponding guide holes. The slow-closing component includes a stop block and a first spring. The outer end surface of the stop block is an inclined surface. An axial guide through hole is provided at the outer end of the stop block, and a radial guide through hole is provided on the side of the stop block. The present invention has small opening and closing torques, which can make the opening and closing operations of the valve easier. At the same time, while meeting the selection requirements of large-diameter pipelines, the diameter of the valve stem is small, greatly reducing the cost.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and particularly to a low-torque globe valve. Background Art

[0002] The closing principle of a globe valve is that, relying on the axial pressure of the valve stem, the sealing surface of the valve disc is closely fitted with the sealing surface of the valve seat to prevent the medium from flowing upward. However, this structure belongs to a forced-sealing structure. Therefore, when the valve is closed, pressure must be applied to the valve disc to ensure that the sealing surface does not leak. When the medium enters the valve from below the valve disc, the resistance that the operating force needs to overcome is the friction between the valve stem and the packing and the thrust generated by the pressure of the medium. The force required to close the valve is greater than the force required to open the valve. Therefore, the diameter of the valve stem needs to be large, otherwise the valve stem may be bent. Especially when the diameter needs to reach above DN200, the diameter of the valve stem needs to be very large, and the operating torque for closing also needs to be greater. Due to the above structure, when making a globe valve with a large diameter, especially above DN200, a large valve stem diameter and a large operating torque are required, but it may not necessarily meet the requirements of the sealing performance, that is, it may not necessarily achieve zero leakage, which brings inconvenience to users. At the same time, the large diameter of the valve stem results in high costs and it is difficult to meet the requirements of large-diameter pipelines for globe valves. Summary of the Invention

[0003] The purpose of the present invention is to provide a low-torque globe valve. The present invention has small opening and closing torques, which can make the opening and closing operations of the valve easier. At the same time, while meeting the selection requirements of large-diameter pipelines, the diameter of the valve stem is smaller, greatly reducing the cost.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a low-torque stop valve, comprising a valve body, a valve cover, a valve stem, a valve disc and a valve seat, the valve cover being installed at the upper end of the valve body, the valve cover being provided with a valve hole, the valve stem passing through the valve hole, the valve disc being installed at the inner end of the valve stem, a first flow channel and a second flow channel being provided in the valve body, a flow port being provided between the first flow channel and the second flow channel, the valve seat being installed on the flow port, a first conical sealing surface being provided on the valve seat, and a second conical sealing surface matching the first conical sealing surface being provided on the valve disc; the inner periphery of the valve seat is matched with the outer periphery of the valve disc, a plurality of groups of slow-closing components are installed on the valve seat, a plurality of guide holes having a number equivalent to the slow-closing components are uniformly provided on the inner wall of the valve seat along the circumferential direction, and an end surface of the valve seat close to the second flow channel A plurality of first pressure relief holes corresponding to the number of the guide holes are provided in the circumferential direction of the upper edge, the first pressure relief holes extend axially along the valve seat and are connected with the corresponding guide holes, the slow closing component is installed in the corresponding guide hole, the slow closing component includes a stop block and a first spring, the first spring is arranged in the guide hole and abuts against the inner end of the stop block, the outer end face of the stop block is an inclined surface, an axial guide hole is axially provided at the outer end of the stop block, a radial guide hole connected with the axial guide hole is provided on the side of the stop block, when the valve disc is completely separated from the valve seat, the first spring pushes the stop block out to make the radial guide hole connect with the first pressure relief hole, when the valve disc gradually approaches the valve seat, the side of the valve disc abuts against the outer end of the stop block to push the stop block into the guide hole, and the radial guide hole on the stop block is gradually staggered from the first pressure relief hole.

[0005] By adopting the above technical solution, in the initial state (i.e., the valve flap is completely separated from the valve seat), under the action of the first spring, the radial guide hole on the stop and through block is completely communicated with the first pressure relief hole on the valve seat. When the valve is closed, the valve stem drives the valve flap to move towards the valve seat. During the downward movement of the valve flap, the side of the valve flap abuts against the outer end of the stop and through block, and gradually pushes the stop and through block towards the inner end of the guide hole until the second conical sealing surface on the valve flap is completely pressed against the first conical sealing surface on the valve seat, at which time the radial guide hole on the stop and through block is completely offset from the first pressure relief hole on the valve seat, thus realizing the complete closing of the valve. It is worth mentioning that when the outer periphery of the valve flap cooperates with the outer periphery of the valve seat, it is a one-stage closing process. At this time, the main flow channel of the valve seat has been closed, but the first pressure relief hole on the valve seat is in an open state. Subsequently, the downward movement of the valve flap causes the stop and through block to retract, making the flow area between the radial guide hole and the first pressure relief hole gradually decrease until it is completely closed, realizing the two-stage closing process. The two-stage closing effectively reduces the torque required to close the valve, making the closing operation of the valve easier. At the same time, it also avoids the huge pressure borne by the valve stem due to the instantaneous closing of the valve, playing a role in protecting the valve stem. In addition, when the valve is opened, the medium first enters the second flow channel through the first pressure relief hole of the valve seat. When the valve flap completely leaves the valve seat, the medium then enters the second flow channel through the main flow channel of the valve seat, playing a role in slow opening, which can avoid the occurrence of water hammer and play a role in protecting the valve body and the valve flap.

[0006] The present invention is further arranged such that the slow closing assembly further includes a guide rod. The guide rod includes a fixed portion with a circular cross-section and a guiding portion with a regular quadrilateral cross-section. A fixing groove is formed at the inner end of the guide hole. The fixed portion is inserted into the fixing groove, and the fixed portion and the fixing groove are in interference fit. A guiding hole matching the guiding portion is formed at the inner end of the stop and through block. A limiting block for limiting the stop and through block is further arranged at a position on the inner wall of the guide hole close to the outer end.

[0007] By adopting the above technical solution, the stop and through block can be limited and guided, so that under the action of the first spring, it can be accurately pushed to the limiting position to communicate the radial guide hole with the first pressure relief hole, and at the same time, when retracting, the radial guide hole can be completely offset from the first pressure relief hole.

[0008] The present invention is further arranged such that a first sealing ring for sealingly cooperating with the inner wall of the guide hole is respectively installed at positions on both sides of the radial guide hole on the stop and through block.

[0009] By adopting the above technical solution, the sealing performance between the conduction block and the inner wall of the guide hole can be improved, and a small amount of medium leakage from the gap between the two during valve closing can be avoided.

[0010] The present invention is further configured such that a plurality of overflow holes are uniformly opened along the circumferential direction at positions below the valve disc on the inner wall of the valve seat corresponding to the valve disc, an annular overflow cavity is circumferentially arranged inside the valve seat, the inner ends of the plurality of overflow holes are connected with the annular overflow cavity, an overflow channel connected with the annular overflow cavity is provided on the side walls of the plurality of guide holes, and a plurality of second pressure relief holes connected with the guide holes are provided on the upper end of the valve seat, a forced pressure relief assembly is installed on the overflow channel, when the stop block is pressed back into the guide hole by the valve disc, the radial guide holes on the stop block are connected with the second pressure relief holes, and when the stop block is pushed out of the guide hole by the first spring, the radial guide holes on the stop block are staggered with the second pressure relief holes.

[0011] By adopting the above technical solution, when the valve is closed, the radial guide hole on the stop block is connected to the second pressure relief hole. If the pressure of the medium upstream of the valve is suddenly too high, the forced pressure relief component will be opened, and the medium will pass through the overflow hole, the annular overflow chamber, the overflow channel, the radial guide hole and the second pressure relief hole in sequence to enter the second flow channel for pressure relief, so as to allow a small amount of medium to pass through, so as to buy reaction time for the staff and avoid major safety accidents caused by high pressure (such as high-pressure explosion).

[0012] The present invention is further configured as follows: the forced pressure relief assembly includes a stop valve core, a support block and a second spring; the overflow channel includes a threaded portion, a first guide portion and a second guide portion with diameters decreasing successively in a direction away from the guide hole; the support block is threadedly connected to the threaded portion; a first flow hole is axially provided in the middle of the support block; an end of the support block close to the corresponding guide hole is provided with a hexagonal operating portion; the stop valve core is axially slidably arranged in the first guide portion; a plurality of second flow holes connected at both ends are circumferentially provided on the stop valve core; a guide protrusion for extending into the second guide portion is provided at one end of the stop valve core away from the guide hole; a second sealing ring for sealing with the second guide portion is installed on the outer periphery of the guide protrusion; a first positioning groove is provided on one end of the support block close to the stop valve core; a second positioning groove is provided on one end of the stop valve core close to the support block; and two ends of the second spring are respectively embedded in the first positioning groove and the second positioning groove.

[0013] By adopting the above technical solution, when the upstream medium pressure is greater than the spring force and the gravity of the stop valve core, the forced pressure relief component will open. The structure is simple and reliable and can effectively play a role of insurance.

[0014] The present invention is further configured such that the valve seat includes a lower mounting seat and an upper sealing seat, the lower mounting seat and the upper sealing seat are connected together by a plurality of screws, the lower mounting seat is threadedly connected to the flow port, the overflow hole and the annular overflow chamber are arranged on the lower mounting seat, and the overflow channel, the guide hole, the first pressure relief hole, and the second pressure relief hole are arranged on the upper sealing seat.

[0015] By adopting the above technical solutions, it is not only convenient for the processing of the overflow holes, annular overflow chambers, overflow channels, guide holes, first pressure relief holes, and second pressure relief holes, but also the connection structure between the lower mounting seat and the upper sealing seat is simple and reliable, which is conducive to production operations.

[0016] The present invention is further configured such that on the upper end surface of the lower mounting seat, an annular positioning groove is respectively provided at positions corresponding to the inner and outer sides of the annular overflow chamber, two annular positioning protrusions that fit with the annular positioning grooves are provided on the lower end surface of the upper sealing seat, and a third sealing ring is clamped between the annular positioning protrusion and the corresponding annular positioning groove.

[0017] By adopting the above technical solutions, the sealing performance between the lower mounting seat and the upper sealing seat can be ensured, and the leakage of internal medium from the gap between the lower mounting seat and the upper sealing seat when the valve is closed can be avoided.

[0018] The present invention is further configured such that an installation cavity for inserting the inner end of the valve stem is provided on the valve flap, a limiting flange extending outwardly is provided at the inner end of the valve stem, a valve flap cover for pressing the limiting flange against the installation cavity is threadedly connected to the valve flap, an installation groove is provided at a position corresponding to the inner end of the installation cavity on the valve flap, and a thrust pad for abutting against the inner end of the valve stem is embedded in the installation groove.

[0019] By adopting the above technical solutions, an effective connection between the valve flap and the valve stem can be achieved, and the connection structure is simple and reliable, and the disassembly and assembly are very convenient.

[0020] The present invention is further configured to further include a sealing assembly, the sealing assembly includes a pressing plate, a pressing sleeve, packing, and a sealing seat. The packing seat is sleeved on the outer periphery of the valve stem, and the outer periphery of the packing seat is threadedly connected to the inner wall of the valve hole. A limiting flange extending outwardly and abutting against the inner end surface of the valve cover is provided at the lower end of the packing seat. The packing is arranged at a position in the valve hole corresponding to the upper side of the sealing seat. The pressing plate is connected to the valve stem through a loose joint bolt, and the pressing plate abuts against the upper end of the pressing sleeve, so that the pressing sleeve presses the packing in the valve hole above the sealing seat.

[0021] By adopting the above technical solutions, compared with the existing method of installing sealing packing in a sealing groove, this structure facilitates the removal of the sealing packing and is conducive to later maintenance operations.

[0022] The present invention is further configured such that a rubber pad is connected to the inner end of the sealing seat by screws.

[0023] By adopting the above technical solutions, the situation that the valve flap rapidly moves upward and impacts the inner wall of the valve cover due to the user's incorrect operation, resulting in damage to the valve components, can be avoided, and the effect of protecting the valve can be achieved. Description of the Drawings

[0024] Figure 1It is a schematic structural diagram of the whole of the present invention;

[0025] Figure 2 It is a schematic structural diagram of the cooperation between the valve flap and the valve seat of the present invention;

[0026] Figure 3 It is Figure 2 an enlarged structural diagram of part A in

[0027] Figure 4 It is a schematic structural diagram of the sealing component of the present invention.

[0028] In the figure: 1. Valve body; 2. Valve cover; 3. Valve stem; 4. Valve flap; 5. Valve seat; 6. Valve hole; 7. First flow channel; 8. Second flow channel; 9. Flow-through port; 10. First conical sealing surface; 11. Second conical sealing surface; 12. Slow-closing component; 13. Guide hole; 14. First pressure relief hole; 15. Stop-and-pass block; 16. First spring; 17. Axial guide through hole; 18. Radial guide through hole; 19. Guide rod; 20. Fixed part; 21. Guide part; 22. Fixed groove; 23. Guide hole; 24. Limit block; 25. First sealing ring; 26. Overflow hole; 27. Annular overflow cavity; 28. Overflow channel; 29. Second pressure relief hole; 30. Forced pressure relief component; 31. Stop-and-pass valve core; 32. Support block; 33. Second spring; 34. Threaded part; 35. First flow guiding part; 36. Second flow guiding part; 37. First flow-through hole; 38. Hexagonal operation part; 39. Second flow-through hole; 40. Guide convex part; 41. Second sealing ring; 42. First positioning groove; 43. Second positioning groove; 44. Lower mounting seat; 45. Upper sealing seat; 46. Annular positioning groove; 47. Annular positioning protrusion; 48. Third sealing ring; 49. Installation cavity; 50. Limit flange; 51. Valve flap cover; 52. Installation groove; 53. Thrust pad; 54. Sealing component; 55. Pressure plate; 56. Pressure sleeve; 57. Packing; 58. Sealing seat; 59. Limit convex edge; 60. Rubber pad. Specific embodiments

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] Embodiment: As shown in the attached Figures 1 to 4The shown low-torque globe valve includes a valve body 1, a valve cover 2, a valve stem 3, a valve disc 4 and a valve seat 5. The valve cover 2 is installed at the upper end of the valve body 1. A valve hole 6 is formed in the valve cover 2. The valve stem 3 penetrates through the valve hole 6. The valve disc 4 is installed at the inner end of the valve stem 3. The outer end of the valve stem 3 is connected to a handwheel. The rotation of the valve stem 3 realizes lifting and lowering. A first flow channel 7 and a second flow channel 8 are provided in the valve body 1. An overflow port 9 is provided between the first flow channel 7 and the second flow channel 8. The valve seat 5 is installed on the overflow port 9. A first conical sealing surface 10 is provided on the valve seat 5. A second conical sealing surface 11 that matches the first conical sealing surface 10 is provided on the valve disc 4. The inner circumference of the valve seat 5 is adapted to the outer circumference of the valve disc 4. A plurality of slow-closing assemblies 12 are installed on the valve seat 5. A plurality of guide holes 13 equal in number to the slow-closing assemblies 12 are evenly formed in the inner wall of the valve seat 5 along the circumferential direction. A plurality of first pressure relief holes 14 equal in number to the guide holes 13 are formed in the end face of the valve seat 5 close to the second flow channel 8 along the circumferential direction. The first pressure relief holes 14 extend along the axial direction of the valve seat 5 and are communicated with the corresponding guide holes 13. The slow-closing assemblies 12 are installed in the corresponding guide holes 13. The slow-closing assembly 12 includes a stop block 15 and a first spring 16. The first spring 16 is arranged in the guide hole 13 and abuts against the inner end of the stop block 15. The outer end face of the stop block 15 is an inclined surface. An axial guide through hole 17 is axially arranged at the outer end of the stop block 15. A radial guide through hole 18 communicated with the axial guide through hole 17 is formed in the side part of the stop block 15. When the valve disc 4 is completely separated from the valve seat 5, the first spring 16 pushes out the stop block 15 to make the radial guide through hole 18 communicate with the first pressure relief hole 14. When the valve disc 4 gradually approaches the valve seat 5, the side part of the valve disc 4 abuts against the outer end of the stop block 15 to push the stop block 15 into the guide hole 13, and the radial guide through hole 18 on the stop block 15 is gradually staggered from the first pressure relief hole 14.In the initial state (i.e., when the valve flap 4 is completely separated from the valve seat 5), under the action of the first spring 16, the radial guide hole 18 on the non-return and through-block 15 is completely communicated with the first pressure relief hole 14 on the valve seat 5. When the valve is closed, the valve stem 3 drives the valve flap 4 to move towards the valve seat 5. During the downward movement of the valve flap 4, the side of the valve flap 4 abuts against the outer end of the non-return and through-block 15 and gradually pushes the non-return and through-block 15 towards the inner end of the guide hole 13 until the second conical sealing surface 11 on the valve flap 4 is completely pressed against the first conical sealing surface 10 on the valve seat 5. At this time, the radial guide hole 18 on the non-return and through-block 15 is completely misaligned with the first pressure relief hole 14 on the valve seat 5, thus achieving the complete closing of the valve. It is worth mentioning that when the outer periphery of the valve flap 4 cooperates with the outer periphery of the valve seat 5, it is a one-stage closing process. At this time, the main flow channel of the valve seat 5 has been closed, but the first pressure relief hole 14 on the valve seat 5 is in an open state. Subsequently, the downward movement of the valve flap 4 causes the non-return and through-block 15 to retract, resulting in a gradual reduction in the flow area between the radial guide hole 18 and the first pressure relief hole 14 until it is completely closed, achieving a two-stage closing process. The two-stage closing effectively reduces the torque required to close the valve, making the closing operation of the valve easier. At the same time, it also avoids the huge pressure borne by the valve stem 3 due to the instantaneous closing of the valve, protecting the valve stem 3. In addition, when the valve is opened, the medium first enters the second flow channel 8 through the first pressure relief hole 14 of the valve seat 5. When the valve flap 4 completely leaves the valve seat 5, the medium then enters the second flow channel 8 through the main flow channel of the valve seat 5, achieving a slow opening effect, which can avoid the occurrence of water hammer and protect the valve body 1 and the valve flap 4.

[0031] As shown in the Figure 3 appendix, the slow-closing component 12 further includes a guide rod 19. The guide rod 19 includes a fixed portion 20 with a circular cross-section and a guiding portion 21 with a regular quadrilateral cross-section. A fixed groove 22 is opened at the inner end of the guide hole 13. The fixed portion 20 is inserted into the fixed groove 22, and the fixed portion 20 and the fixed groove 22 are in interference fit. A guiding hole 23 matching the guiding portion 21 is opened at the inner end of the non-return and through-block 15. A limiting block 24 for limiting the non-return and through-block 15 is further provided at a position on the inner wall of the guide hole 13 close to the outer end. This design can limit and guide the non-return and through-block 15, so that under the action of the first spring 16, it is accurately pushed to the limiting position to communicate the radial guide hole 18 with the first pressure relief hole 14, and at the same time, the radial guide hole 18 can be completely misaligned with the first pressure relief hole 14 when retracting.

[0032] As shown in the Figure 3As shown, the stop block 15 is provided with a first sealing ring 25 for sealing with the inner wall of the guide hole 13 at the positions corresponding to both sides of the radial guide hole 18, that is, a first annular groove is provided on the stop block 15, and the first sealing ring 25 is embedded in the first annular groove. This design can improve the sealing between the guide block and the inner wall of the guide hole 13, and prevent a small amount of medium from leaking from the gap between the two when the valve is closed.

[0033] As attached Figure 3 As shown, a plurality of overflow holes 26 are uniformly opened along the circumferential direction at the inner wall of the valve seat 5 corresponding to the position below the valve disc 4, an annular overflow cavity 27 is circumferentially arranged inside the valve seat 5, the inner ends of the plurality of overflow holes 26 are connected to the annular overflow cavity 27, an overflow channel 28 connected to the annular overflow cavity 27 is provided on the side walls of the plurality of guide holes 13, and a plurality of second pressure relief holes 29 connected to the guide holes 13 are provided on the upper end of the valve seat 5, and the inner diameter of the second pressure relief hole 29 is much smaller than the inner diameter of the first pressure relief hole 14. The second pressure relief hole 29 can only have a slight pressure relief effect. A forced pressure relief assembly 30 is installed on the overflow channel 28. When the stop block 15 is pressed back to the guide hole 13 by the valve disc 4, the radial guide hole 18 on the stop block 15 is connected with the second pressure relief hole 29. When the stop block 15 is pushed out of the guide hole 13 by the first spring 16, the radial guide hole 18 on the stop block 15 is staggered with the second pressure relief hole 29. When the valve is closed, the radial guide hole 18 on the stop block 15 is connected with the second pressure relief hole 29. If the pressure of the medium upstream of the valve is suddenly too high, the forced pressure relief assembly 30 will be opened, and the medium will enter the second flow channel 8 through the overflow hole 26, the annular overflow chamber 27, the overflow channel 28, the radial guide hole 18 and the second pressure relief hole 29 in sequence for pressure relief, so as to allow a small amount of medium to pass through to buy reaction time for the staff and avoid major safety accidents caused by high pressure (such as high pressure explosion).

[0034] As attached Figure 3As shown in the figure, the forced pressure relief component 30 includes a check valve core 31, a support block 32, and a second spring 33. The overflow channel 28 includes a threaded portion 34, a first diversion portion 35, and a second diversion portion 36 with successively decreasing diameters in the direction away from the guide hole 13. The support block 32 is threadedly connected to the threaded portion 34. The threaded portion 34 has internal threads, and the support block 32 has external threads. A first flow-through hole 37 is axially formed in the middle of the support block 32. One end of the support block 32 close to the corresponding guide hole 13 is provided with a hexagonal operation portion 38. The check valve core 31 is axially slidably disposed in the first diversion portion 35. A plurality of second flow-through holes 39 that are communicated at both ends are circumferentially provided on the check valve core 31. One end of the check valve core 31 away from the guide hole 13 is provided with a guiding convex portion 40 for extending into the second diversion portion 36. A second sealing ring 41 for sealing cooperation with the second diversion portion 36 is installed on the outer periphery of the guiding convex portion 40. A first positioning groove 42 is formed at one end of the support block 32 close to the check valve core 31. A second positioning groove 43 is formed at one end of the check valve core 31 close to the support block 32. Both ends of the second spring 33 are respectively embedded in the first positioning groove 42 and the second positioning groove 43. When the upstream medium pressure is greater than the spring force and the gravity of the check valve core 31, the forced pressure relief component 30 will open. This structure is simple and reliable and can effectively play an insurance role.

[0035] As shown in the attached Figure 2 figure, the valve seat 5 includes a lower mounting seat 44 and an upper sealing seat 45. The lower mounting seat 44 and the upper sealing seat 45 are connected together by a plurality of screws. The lower mounting seat 44 is threadedly connected to the flow-through port 9, that is, the flow-through port 9 has internal threads, and the lower mounting seat 44 has external threads that match the internal threads. The overflow hole 26 and the annular overflow chamber 27 are provided on the lower mounting seat 44. The overflow channel 28, the guide hole 13, the first pressure relief hole 14, and the second pressure relief hole 29 are provided on the upper sealing seat 45. This design not only facilitates the processing of the overflow hole 26, the annular overflow chamber 27, the overflow channel 28, the guide hole 13, the first pressure relief hole 14, and the second pressure relief hole 29, but also the connection structure between the lower mounting seat 44 and the upper sealing seat 45 is simple and reliable, which is conducive to production operations.

[0036] As shown in the attached Figure 3 figure, annular positioning grooves 46 are respectively formed on the upper end surface of the lower mounting seat 44 at positions corresponding to the inside and outside of the annular overflow chamber 27. Two annular positioning protrusions 47 that fit with the annular positioning grooves 46 are provided on the lower end surface of the upper sealing seat 45, and a third sealing ring 48 is clamped between the annular positioning protrusion 47 and the corresponding annular positioning groove 46. This design can ensure the sealing performance between the lower mounting seat 44 and the upper sealing seat 45 and prevent internal medium from leaking from the gap between the lower mounting seat 44 and the upper sealing seat 45 when the valve is closed.

[0037] As shown in the appendix Figure 2 As shown, an installation cavity 49 for inserting the inner end of the valve stem 3 is provided on the valve flap 4. The inner end of the valve stem 3 is provided with a limiting flange 50 extending towards the outer circumference. A valve flap cover 51 for tightly pressing the limiting flange 50 in the installation cavity 49 is threadedly connected to the valve flap 4. An installation groove 52 is provided at the position corresponding to the inner end of the installation cavity 49 on the valve flap 4. A thrust pad 53 for abutting against the inner end of the valve stem 3 is embedded in the installation groove 52. This design can achieve an effective connection between the valve flap 4 and the valve stem 3, and the connection structure is simple and reliable, and the disassembly and assembly are very convenient.

[0038] As shown in the appendix Figure 1 and the appendix Figure 4 As shown, a sealing assembly 54 is further included. The sealing assembly 54 includes a pressing plate 55, a pressing sleeve 56, a packing 57, and a sealing seat 58. The packing seat is sleeved on the outer circumference of the valve stem 3, and the outer circumference of the packing seat is threadedly connected to the inner wall of the valve hole 6. The lower end of the packing seat is provided with a limiting convex edge 59 extending towards the outer circumference and abutting against the inner end face of the valve cover 2. The packing 57 is arranged at the position in the valve hole 6 above the sealing seat 58. The pressing plate 55 is connected to the valve stem 3 through a loose joint bolt, and the pressing plate 55 abuts against the upper end of the pressing sleeve 56, so that the pressing sleeve 56 presses the packing 57 tightly in the valve hole 6 above the sealing seat 58. Compared with the existing method of installing the sealing packing 57 with a sealing groove, this structure facilitates the removal of the sealing packing 57 and is conducive to later maintenance operations.

[0039] As shown in the appendix Figure 4 As shown, a rubber pad 60 is connected to the inner end of the sealing seat 58 by screws. An indentation groove is provided at the outer end corresponding to the screw hole on the rubber pad 60 for the embedding of the screw head, so as to avoid the screw head protruding above the lower edge of the rubber pad 60. This design can prevent the situation that the valve flap 4 rapidly moves upward and impacts the inner wall of the valve cover 2 due to misoperation by the user, resulting in damage to the valve components, and plays a role in protecting the valve.

Claims

1. A low torque stop valve, comprising a valve body (1), a valve cover (2), a valve stem (3), a valve flap (4) and a valve seat (5), wherein the valve cover (2) is mounted on the upper end of the valve body (1), a valve hole (6) is formed on the valve cover (2), the valve stem (3) passes through the valve hole (6), the valve flap (4) is mounted on the inner end of the valve stem (3), a first flow channel (7) and a second flow channel (8) are formed in the valve body (1), a flow port (9) is formed between the first flow channel (7) and the second flow channel (8), the valve seat (5) is mounted on the flow port (9), a first conical sealing surface (10) is formed on the valve seat (5), and a second conical sealing surface (11) matched with the first conical sealing surface (10) is formed on the valve flap (4); Features: The inner periphery of the valve seat (5) is matched with the outer periphery of the valve disc (4); a plurality of slow-closing components (12) are installed on the valve seat (5); a plurality of guide holes (13) whose number is equal to the number of the slow-closing components (12) are evenly opened on the inner wall of the valve seat (5) along the circumferential direction; a plurality of first pressure relief holes (14) whose number is equal to the number of the guide holes (13) are opened on the end surface of the valve seat (5) close to the second flow channel (8) along the circumferential direction; the first pressure relief holes (14) extend axially along the valve seat (5) and are connected to the corresponding guide holes (13); the slow-closing components (12) are installed in the corresponding guide holes (13); the slow-closing components (12) include a stop block (15) and a first spring (16); the first spring (16) is arranged in the guide hole (13) The stop block (15) is provided with an axial guide hole (17) at the outer end thereof in the axial direction, and a radial guide hole (18) connected to the axial guide hole (17) is provided at the side of the stop block (15). When the valve disc (4) and the valve seat (5) are completely separated, the first spring (16) pushes the stop block (15) out to connect the radial guide hole (18) with the first pressure relief hole (14). When the valve disc (4) gradually approaches the valve seat (5), the side of the valve disc (4) and the outer end of the stop block (15) are abutted to push the stop block (15) into the guide hole (13), and the radial guide hole (18) on the stop block (15) and the first pressure relief hole (14) are gradually staggered.

2. The low torque cut-off valve according to claim 1, Features: The slow closing assembly (12) further comprises a guide rod (19), wherein the guide rod (19) comprises a fixing portion (20) having a circular cross section and a guiding portion (21) having a regular quadrilateral cross section; a fixing groove (22) is provided at the inner end of the guide hole (13); the fixing portion (20) is inserted into the fixing groove (22), and the fixing portion (20) and the fixing groove (22) are interference fit; a guide hole (23) matching the guiding portion (21) is provided at the inner end of the stop block (15); and a limit block (24) for limiting the stop block (15) is further provided at a position near the outer end of the inner wall of the guide hole (13).

3. The low torque cut-off valve according to claim 1, Features: A first sealing ring (25) for sealingly mating with the inner wall of the guide hole (13) is respectively installed at positions on both sides of the radial guide through hole (18) corresponding to the stop and through block (15).

4. The low-torque globe valve according to claim 1, wherein: A plurality of overflow holes (26) are evenly formed in the inner wall of the valve seat (5) along the circumferential direction at a position corresponding to the lower part of the valve flap (4). An annular overflow chamber (27) is arranged in the valve seat (5) along the circumferential direction. The inner ends of the plurality of overflow holes (26) are all communicated with the annular overflow chamber (27). An overflow channel (28) communicated with the annular overflow chamber (27) is arranged on the side wall of each of the plurality of guide holes (13). A plurality of second pressure relief holes (29) communicated with the guide holes (13) are arranged at the upper end of the valve seat (5). A forced pressure relief assembly (30) is installed on the overflow channel (28). When the stop and through block (15) is pressed back into the guide hole (13) by the valve flap (4), the radial guide through hole (18) on the stop and through block (15) is communicated with the second pressure relief hole (29). When the stop and through block (15) is pushed out of the guide hole (13) by the first spring (16), the radial guide through hole (18) on the stop and through block (15) is offset from the second pressure relief hole (29).

5. The low-torque globe valve according to claim 4, wherein: The forced pressure relief assembly (30) includes a stop valve core (31), a support block (32) and a second spring (33). The overflow channel (28) includes a threaded portion (34), a first diversion portion (35) and a second diversion portion (36) with diameters decreasing in sequence in a direction away from the guide hole (13). The support block (32) is threadedly connected to the threaded portion (34). A first flow through hole (37) is axially formed in the middle of the support block (32). A hexagonal operation portion (38) is arranged at one end of the support block (32) close to the corresponding guide hole (13). The stop valve core (31) is axially slidably arranged in the first diversion portion (35). A plurality of second flow through holes (39) with both ends communicated are arranged on the stop valve core (31) along the circumferential direction. A guide convex portion (40) for extending into the second diversion portion (36) is arranged at one end of the stop valve core (31) away from the guide hole (13). A second sealing ring (41) for sealingly mating with the second diversion portion (36) is installed on the outer periphery of the guide convex portion (40). A first positioning groove (42) is formed at one end of the support block (32) close to the stop valve core (31). A second positioning groove (43) is formed at one end of the stop valve core (31) close to the support block (32). The two ends of the second spring (33) are respectively embedded in the first positioning groove (42) and the second positioning groove (43).

6. The low-torque globe valve according to claim 5, wherein: The valve seat (5) includes a lower mounting seat (44) and an upper sealing seat (45). The lower mounting seat (44) and the upper sealing seat (45) are connected together by a plurality of screws. The lower mounting seat (44) is threadedly connected to the flow-through port (9). The overflow hole (26) and the annular overflow chamber (27) are provided on the lower mounting seat (44). The overflow channel (28), the guide hole (13), the first pressure relief hole (14), and the second pressure relief hole (29) are provided on the upper sealing seat (45).

7. The low-torque globe valve according to claim 6, wherein: On the upper end surface of the lower mounting seat (44), an annular positioning groove (46) is respectively formed at positions corresponding to the inner and outer sides of the annular overflow chamber (27). On the lower end surface of the upper sealing seat (45), two annular positioning protrusions (47) that fit with the annular positioning groove (46) are provided. And a third sealing ring (48) is clamped between the annular positioning protrusion (47) and the corresponding annular positioning groove (46).

8. The low-torque globe valve according to claim 1, wherein: An installation cavity (49) for the inner end of the valve stem (3) to insert is provided on the valve flap (4). A limiting flange (50) extending outward in the circumferential direction is provided at the inner end of the valve stem (3). A valve flap cover (51) for pressing the limiting flange (50) tightly in the installation cavity (49) is threadedly connected to the valve flap (4). An installation groove (52) is formed at a position corresponding to the inner end of the installation cavity (49) on the valve flap (4). A thrust pad (53) for abutting against the inner end of the valve stem (3) is embedded in the installation groove (52).

9. The low-torque globe valve according to claim 1, wherein: It further includes a sealing assembly (54). The sealing assembly (54) includes a pressing plate (55), a pressing sleeve (56), packing (57), and a sealing seat (58). The packing seat is sleeved on the outer circumference of the valve stem (3). And the outer circumference of the packing seat is threadedly connected to the inner wall of the valve hole (6). A limiting flange (59) extending outward in the circumferential direction and abutting against the inner end surface of the valve cover (2) is provided at the lower end of the packing seat. The packing (57) is arranged at a position in the valve hole (6) corresponding to the upper side of the sealing seat (58). The pressing plate (55) is connected to the valve stem (3) through a loose joint bolt. And the pressing plate (55) abuts against the upper end of the pressing sleeve (56), so that the pressing sleeve (56) presses the packing (57) tightly in the valve hole (6) above the sealing seat (58).

10. The low-torque globe valve according to claim 9, wherein: A rubber pad (60) is connected to the inner end of the sealing seat (58) by screws.

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