Ball valve

Abstract

The utility model relates to the technical field of valves, and discloses a ball valve, which comprises a valve body, the ball body is arranged in the valve body; the two valve seats are respectively arranged on two sides of the ball body and are arranged in the valve body; one end of the stuffing box is connected with the valve body; one end of the valve rod penetrates through the stuffing box and is connected with the ball body; the gland is arranged between the other end of the stuffing box and the valve rod, and a containing cavity opposite to an opening of the valve body is defined between the gland and the valve rod; the valve rod filler is arranged in the accommodating cavity and is far away from the valve body; the valve rod is sleeved with the packing pressing piece, the packing pressing piece is fixed to the gland, and the packing pressing piece is suitable for tightly pressing the valve rod packing to the gland. When the valve rod packing is far away from high temperature and is radiated by the packing box and the valve rod and transferred to the gland where the valve rod packing is located, the temperature is reduced, the valve rod packing is not prone to failure, the service life is prolonged, and the replacement frequency is reduced. And the valve rod packing is arranged between the gland and the valve rod, so that the assembly is more convenient, the assembly is more labor-saving, and the efficiency is higher.

Description

Technical Field

[0001] The utility model relates to the technical field of valves, in particular to a ball valve. Background Art

[0002] At present, ball valves are widely used in various chemical industries. With the development of science and technology, valve users have higher and higher requirements for valves, such as high temperature, high pressure, strong corrosion, high freezing point organic matter and polymer media, hard sealing requirements, etc.

[0003] In the related art, the ball valve includes a valve body, a ball, a valve seat, a valve stem, a packing, etc. The packing is arranged between the valve body and the valve stem. When the ball valve is suitable for high temperature, high pressure, high freezing point organic matter and polymer working conditions, when the medium passes through the ball valve, the heat of the medium is transferred to the packing through the valve body and the valve stem. The temperature of the valve body and the valve body where the packing is located is relatively high. The packing can easily soften or melt at high temperature, resulting in failure of the seal and a sharp reduction in service life, requiring frequent replacement of the packing. Utility Model Content

[0004] In view of this, the utility model provides a ball valve to solve the problem that the packing is easily ineffective under high temperature conditions because the packing is arranged between the valve body and the valve stem.

[0005] The utility model provides a ball valve, comprising: a valve body; a sphere, which is arranged inside the valve body; two valve seats, which are respectively arranged on both sides of the sphere and inside the valve body; a stuffing box, one end of which is connected to the valve body; a valve stem, one end of which passes through the stuffing box and is connected to the sphere and the other end of which extends out of the stuffing box; a gland, which is arranged between the other end of the stuffing box and the valve stem, and the gland and the valve stem form an accommodating cavity with an opening facing away from the valve body; a valve stem packing, which is arranged in the accommodating cavity and is arranged away from the valve body; a packing pressing piece, which is sleeved on the valve stem and fixed on the gland, and the packing pressing piece is suitable for pressing the valve stem packing onto the gland.

[0006] Beneficial effects: a stuffing box is arranged on the valve body, a gland is arranged at one end of the stuffing box away from the valve body, the valve stem packing is arranged between the gland and the packing pressing piece, the position of the valve stem packing is raised, and the valve stem packing is arranged away from the valve body. When the ball valve is suitable for high temperature, high pressure, high freezing point organic matter and polymer working conditions, the heat of the medium is transferred to the outside through the valve body, stuffing box or valve stem. Since the valve stem packing is arranged away from the valve body, that is, the valve stem packing is away from the high temperature, the heat is dissipated by the stuffing box and the valve stem, and when the heat is transferred to the gland where the valve stem packing is located, the temperature has been reduced, and the valve stem packing is not easy to fail, the service life is extended, and the replacement frequency is reduced. In addition, when assembling the ball valve, the stuffing box is first connected to the valve body, and then the valve stem and the gland are assembled, and then the valve stem packing is assembled. The valve stem packing is arranged between the gland and the valve stem, which is more convenient for assembly, more labor-saving and more efficient.

[0007] In an optional embodiment, an upper bearing is provided between the packing pressure piece and the valve stem, and a lower bearing is provided between the lower end of the valve stem and the valve body and the packing box.

[0008] Beneficial effects: bearings are arranged at the upper and lower ends of the valve stem respectively, and the upper bearing is close to the driving mechanism or the operating rod, so the possibility of shaking when the valve stem rotates is relatively small, and the ball valve is more stable when switched. In addition, the two bearings can reduce friction and increase service life.

[0009] In an optional embodiment, a step surface is provided on the valve stem near the gland, and a thrust pad is provided between the step surface and the gland.

[0010] Beneficial effect: The thrust pad is arranged between the step surface of the gland and the valve stem, and the setting position of the thrust pad is also away from high temperature, which prolongs the service life of the thrust pad and reduces the replacement frequency.

[0011] In an optional embodiment, the ball valve also includes a valve cover, a pressure ring, a valve seat packing and an elastic member, the valve cover is connected to one end of the valve body, a valve seat is located between the ball and the valve cover, the pressure ring is arranged between a side of the valve seat facing away from the ball and the valve cover, the pressure ring, the valve cover and the valve seat form an accommodating ring cavity, the valve seat packing is accommodated in the accommodating ring cavity, the elastic member is arranged between a side of the pressure ring facing away from the ball and the valve cover, and the end of the valve cover facing away from the ball has a tightening recess.

[0012] Beneficial effect: The end face of the valve cover adopts a tightening notch, which makes the contact surface larger when assembling the valve cover, and the valve cover has stronger resistance to extrusion. A larger tightening force can be used to tighten the valve cover, realize quantitative compression of the gasket, and ensure high-pressure sealing between the valve body and the valve cover.

[0013] In an optional embodiment, the packing press comprises a pressing sleeve and a pressing plate. The pressing sleeve is arranged on the top of the valve stem packing. A pressing plate is arranged on the top of the pressing sleeve. The pressing plate is fixedly connected to the gland.

[0014] Beneficial effect: The outer circle of the valve stem contacts the inner diameter of the valve stem packing, the pressure plate and the gland are connected by fasteners such as clamping bolts, the bolt force of the clamping bolts acts on the pressure plate and is transmitted to the valve stem packing through the compression sleeve, the valve stem packing is compressed to form a sealing surface to achieve external sealing of the valve stem, and ensure the high temperature and stable sealing performance of the valve.

[0015] In an optional embodiment, the valve seat and the sealing surface of the ball have a hard alloy layer.

[0016] Beneficial effect: The valve seat and ball on the left side of the valve body, and the valve seat and ball on the right side are both metal-to-metal hard seals, and are also sealed through the valve seat packing to achieve double sealing in the valve body, meeting the technical requirements of high temperature, high pressure, and high freezing point media working conditions at 250℃~400℃.

[0017] In an optional embodiment, the cemented carbide layer is a chromium carbide layer or a Stellite alloy layer.

[0018] Beneficial effects: Chromium carbide and Stellite alloy materials have the advantages of high temperature resistance, corrosion resistance, and wear resistance.

[0019] In an optional embodiment, a jacket is provided between the two end flanges of the valve body, the jacket is provided with a through hole for the stuffing box to pass through, the jacket, the valve body and the stuffing box form a cavity, and the cavity is filled with a heat-insulating medium.

[0020] Beneficial effects: A large amount of high-temperature thermal insulation medium can be filled in the cavity, which wraps the hard-sealed ball valve. The high-temperature thermal insulation medium is in full contact with the surface of the valve body, ensuring that the surface of the valve body is in a high-temperature protection state for a long time. The external heat is transferred from the valve body to the channel, ensuring that the medium in the channel is in a high-temperature non-solidified state and can circulate normally. The valve can be opened and closed normally if the medium in the channel does not solidify.

[0021] In an optional embodiment, both ends of the jacket are welded to the valve body, the jacket is welded to the stuffing box, the stuffing box is welded to the valve body, and side flanges are welded to opposite sides of the jacket.

[0022] Beneficial effect: The jacket and the overall outer surface of the valve body are welded together with a large gap, and the side flange provides an inlet and outlet for high-temperature heat-insulating medium in the cavity.

[0023] In an optional embodiment, the jacket comprises two half-jacket bodies, and the two half-jacket bodies are welded.

[0024] Beneficial effect: The ball valve is sealed by nine welds, ensuring that the entire cavity wrapped by the jacket has no external leakage within the high-temperature working temperature range. The seal is reliable and it has obvious advantages when used in high-temperature, high-pressure, high-freezing-point organic and polymer working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A cross-sectional view of a ball valve according to an embodiment of the utility model;

[0027] Figure 2 for Figure 1 A partial schematic diagram of the upper portion of the ball valve shown;

[0028] Figure 3for Figure 1 Schematic diagram of weld distribution of ball valve shown;

[0029] Figure 4 for Figure 3 A side view of a ball valve is shown;

[0030] Figure 5 for Figure 4 A partial enlarged schematic diagram of B in the middle;

[0031] Figure 6 for Figure 1 A partial schematic diagram of the lower part of the ball valve is shown.

[0032] Description of reference numerals:

[0033] 1. Valve body; 2. Valve cover; 201. Tightening notch; 3. Ball; 4. Valve seat; 5. Valve stem; 6. Press ring; 7. Valve seat packing; 801. Upper bearing; 802. Lower bearing; 901. First weld; 902. Second weld; 903. Third weld; 904. Fourth weld; 905. Fifth weld; 906. Sixth weld; 907. Seventh weld; 908. Eighth weld; 909. Ninth weld;

[0034] 10. Gasket; 11. Stem packing; 12. Gland; 13. Side flange; 14. Actuator; 15. Thrust pad; 16. Screw; 17. Plug; 18. Elastic part; 19. Bracket; 20. Bolt; 21. Drive sleeve; 22. Press sleeve; 23. Joint; 24. Jacket; 25. Pressure plate; 26. Stuffing box; 27. Cavity. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0036] Combine the following Figures 1 to 6 , describing an embodiment of the utility model.

[0037] According to an embodiment of the utility model, on the one hand, a ball valve is provided, comprising: a valve body 1, a ball 3, two valve seats 4, a stuffing box 26, a valve stem 5, a gland 12, a valve stem packing 11 and a packing pressing piece. The ball 3 is arranged inside the valve body 1; the two valve seats 4 are arranged on both sides of the ball 3 and inside the valve body 1 respectively; one end of the stuffing box 26 is connected to the valve body 1; one end of the valve stem 5 passes through the stuffing box 26 and is connected to the ball 3 and the other end extends from the stuffing box 26; the gland 12 is arranged between the other end of the stuffing box 26 and the valve stem 5, and the gland 12 and the valve stem 5 form a receiving cavity that opens away from the valve body 1; the valve stem packing 11 is arranged in the receiving cavity and is arranged away from the valve body 1; the packing pressing piece is sleeved on the valve stem 5 and fixed on the gland 12, and the packing pressing piece is suitable for pressing the valve stem packing 11 on the gland 12.

[0038] When using the ball valve of this embodiment, a stuffing box 26 is provided on the valve body 1, a gland 12 is provided at the end of the stuffing box 26 away from the valve body 1, the stem packing 11 is provided between the gland 12 and the packing pressing piece, and the position of the stem packing 11 is raised so that the stem packing 11 is provided away from the valve body 1. When the ball valve is suitable for high temperature, high pressure, high freezing point organic matter and polymer working conditions, the heat of the medium is transferred to the outside through the valve body 1, the stuffing box 26 or the stem 5. Since the stem packing 11 is provided away from the valve body 1, that is, the stem packing 11 is away from the high temperature, the heat is dissipated by the stuffing box 26 and the stem 5, and when the heat is transferred to the gland 12 where the stem packing 11 is located, the temperature has been reduced, and the stem packing 11 is not easy to fail, thereby extending the service life and reducing the replacement frequency. Furthermore, when assembling the ball valve, first connect the stuffing box 26 to the valve body 1, then assemble the valve stem 5 and the gland 12, and then assemble the valve stem stuffing 11, and set the valve stem stuffing 11 between the gland 12 and the valve stem 5, which is easier to assemble, more labor-saving and more efficient.

[0039] In order to overcome the problem of the ball valve being stuck and stable, in one embodiment, an upper bearing 801 is provided between the packing pressure piece and the valve stem 5, and a lower bearing 802 is provided between the lower end of the valve stem 5 and the valve body 1 and the packing box 26. Bearings are provided at the upper and lower ends of the valve stem 5, respectively, and the upper bearing 801 is relatively close to the driving mechanism or the operating rod, so the valve stem 5 is less likely to shake when rotating, and the ball valve is more stable when being switched, and the two bearings can reduce friction and increase service life.

[0040] In one embodiment, the packing pressing piece includes a pressing sleeve 22 and a pressing plate 25. The pressing sleeve 22 is arranged on the top of the valve stem packing 11. The pressing plate 25 is arranged on the top of the pressing sleeve 22. The pressing plate 25 is fixedly connected to the gland 12. The upper bearing 801 and the lower bearing 802 are installed at the matching position of the pressing plate 25, the valve body 1 and the valve stem 5. The upper bearing 801 and the lower bearing 802 form a bearing combination structure to ensure the smooth operation of the valve. The outer circle of the valve stem 5 contacts the inner diameter of the valve stem packing 11. The pressing plate 25 and the gland 12 are connected by fasteners such as the clamping bolt 20. The bolt force of the clamping bolt 20 acts on the pressing plate 25 and is transmitted to the valve stem packing 11 through the pressing sleeve 22. The valve stem packing 11 is compressed to form a sealing surface to achieve the external sealing of the valve stem 5, ensuring the high temperature and stable sealing performance of the valve.

[0041] In one embodiment, the valve stem 5 is provided with a step surface near the gland 12, and a thrust pad 15 is provided between the step surface and the gland 12. The thrust pad 15 is provided between the gland 12 and the step surface of the valve stem 5, and the setting position of the thrust pad 15 is also avoided from high temperature, thereby extending the service life of the thrust pad 15 and reducing the replacement frequency.

[0042] Furthermore, a metal thrust pad 15 is designed between the valve stem 5 and the valve body 1 to reduce friction and provide dual bearing guidance, thereby ensuring smooth valve switching. The valve stem packing 11 is tightened with studs and nuts to ensure the sealing performance of the valve stem packing 11 at high temperature and high pressure.

[0043] In one embodiment, the ball valve further comprises a valve cover 2, a pressure ring 6, a valve seat packing 7 and an elastic member 18. The valve cover 2 is connected to one end of the valve body 1. A valve seat 4 is located between the ball 3 and the valve cover 2. The pressure ring 6 is arranged between the side of the valve seat 4 facing away from the ball 3 and the valve cover 2. The pressure ring 6, the valve cover 2 and the valve seat 4 form a receiving ring cavity, and the valve seat packing 7 is accommodated in the receiving ring cavity. The elastic member 18 is arranged between the side of the pressure ring 6 facing away from the ball 3 and the valve cover 2. The end of the valve cover 2 facing away from the ball 3 has a tightening notch 201. The valve cover 2 and the ball head adopt hard sealing, so that the applicable temperature of the ball valve is within the range of 250℃~400℃ and the applicable pressure is higher than 150LB, so that the ball valve is applicable to the working conditions of organic matter and polymer medium with high temperature, high pressure and high freezing point of 250℃~400℃. The internal sealing structure of the ball valve is a one-way sealing form. A valve cover 2 is installed at the upstream end. Elastic parts 18 such as butterfly springs are installed in the valve cover 2. The butterfly spring provides pre-tightening force to the sealing surface of the valve seat 4 to ensure the low-pressure sealing performance of the ball valve. The strength analysis of the valve body 1, valve cover 2, ball 3, and valve seat 4 and the sealing pressure ratio design are strictly controlled to ensure that the ball valve has excellent pressure-bearing and sealing performance under high temperature of 250°C and above and steam conditions.

[0044] Furthermore, steps are provided inside one end of the valve body 1 and on the outer wall of the valve cover 2, and gaskets 10 are provided between the steps.

[0045] In order to overcome the problem of difficult sealing of the high-pressure valve cover 2 of the insulation valve, a tightening recess 201 is adopted on the end face of the valve cover 2, so that the contact surface is large when the valve cover 2 is assembled, the valve cover 2 is more resistant to extrusion, and a larger tightening force can be used to tighten the valve cover 2, thereby achieving quantitative compression of the gasket 10 and ensuring high-pressure sealing between the valve body 1 and the valve cover 2.

[0046] Specifically, the tightening notch 201 is a pentagon, etc., and the gasket 10 is compressed by rotating clockwise using a tool. The compression amount of the gasket 10 is quantitatively compressed through precise calculation to achieve high-pressure external sealing of the valve.

[0047] Furthermore, threaded holes are drilled at the end flanges at both ends of the valve body 1, the end flanges and the pipeline are connected by studs and nuts, and the valve body 1 is threadedly connected to the valve cover 2, so the connection is reliable.

[0048] Specifically, the elastic member 18 is a butterfly spring, etc. The butterfly spring provides elastic pre-tightening to ensure that the valve has a continuous sealing pre-tightening force to achieve internal sealing of the valve.

[0049] In order to overcome the difficulty in using the ball valve under high temperature and high pressure conditions of high freezing point organic matter and polymers and the problem of its own safety performance, in one embodiment, the sealing surfaces of the ball 3 and the valve seat 4 are both coated with a high temperature resistant metal wear-resistant coating.

[0050] Furthermore, the metal wear-resistant coating is a hard alloy layer, that is, the sealing surface of the valve seat 4 and the ball 3 has a hard alloy layer. The valve seat 4 and the ball 3 on the left side of the valve body 1, and the valve seat 4 and the ball 3 on the right side are both metal-to-metal hard seals, and are also sealed by the valve seat packing 7 to achieve double sealing in the valve body 1, meeting the technical requirements of high temperature, high pressure, and high freezing point medium working conditions of 250℃ to 400℃. The sealing surface of the valve seat 4 and the ball 3 is hardened to form a hard alloy layer.

[0051] Specifically, the cemented carbide layer is a chromium carbide layer or a Stellite alloy layer. Chromium carbide and Stellite alloy materials have the advantages of high temperature resistance, corrosion resistance, wear resistance and the like.

[0052] In order to overcome the problem of the difficulty of heat preservation of the valve under high temperature and high pressure working conditions of organic matter and polymer with high solidification point, in one embodiment, a jacket 24 is provided between the two end flanges of the valve body 1, and a through hole for the stuffing box 26 to pass through is provided on the jacket 24. The jacket 24, the valve body 1 and the stuffing box 26 form a cavity 27, and the cavity 27 is filled with a heat preservation medium. The cavity 27 can be filled with a large amount of high temperature heat preservation medium, and the high temperature heat preservation medium wraps the hard seal ball valve therein. The high temperature heat preservation medium is fully in contact with the surface of the valve body 1, ensuring that the surface of the valve body 1 is in a high temperature protection state for a long time, and the external heat is transferred from the valve body 1 to the channel, ensuring that the medium in the channel is in a high temperature non-solidified state and can circulate normally, and the medium in the channel can open and close the valve normally without solidification.

[0053] Specifically, high-temperature hot oil or high-temperature steam is introduced into the cavity 27 between the jacket 24 and the valve body 1. The high-temperature hot oil or high-temperature steam transfers heat to the channel of the valve body 1, ensuring that the high-freezing point medium (organic matter or polymer) in the channel of the ball valve is in a high-temperature molten state for a long time and is easy to circulate.

[0054] In one embodiment, both ends of the jacket 24 are welded to the valve body 1, the jacket 24 is welded to the stuffing box 26, the stuffing box 26 is welded to the valve body 1, and side flanges 13 are welded to the opposite sides of the jacket 24. The jacket 24 and the overall outer surface of the valve body 1 are welded together with a large gap, and the side flanges 13 provide the cavity 27 with an inlet and outlet for the high-temperature heat-insulating medium.

[0055] Specifically, the valve body 1 is a one-piece structure, with a jacket 24 welded between flanges at both ends, and the jacket 24 and the outer surface of the valve body 1 forming a cavity 27 .

[0056] In one embodiment, the jacket 24 includes two half-jackets, which are welded. The welds of the ball valve as a whole include a first weld 901, a second weld 902, a third weld 903, a fourth weld 904, a fifth weld 905, a sixth weld 906, a seventh weld 907, an eighth weld 908, and a ninth weld 909, that is, the ball valve as a whole is welded and sealed by nine welds, ensuring that the entire cavity 27 wrapped by the jacket 24 has no external leakage within the high-temperature working temperature range, and the sealing is reliable. It is used in high-temperature, high-pressure, high-freezing-point organic and polymer working conditions, and has obvious advantages.

[0057] Specifically, the ball valve adopts a jacket 24 and a hard seal. At this time, the ball valve belongs to a high-temperature and high-pressure metal hard-tight jacket ball valve. The valve body 1 adopts a forging molding process to ensure the reliable performance of the overall material.

[0058] Furthermore, the valve seat filler 7 between the valve seat 4 and the valve body 1 and the valve seat filler 7 between the valve seat 4 and the valve cover 2 are both made of flexible graphite, ensuring that the valve has good sealing performance under high temperature and high pressure conditions.

[0059] Specifically, the valve body 1, the stuffing box 26, the gland 12 flange, the ball 3, the valve stem 5, the valve seat 4, and the valve cover 2 are all integrally forged, and the valve body 1, the valve cover 2, the ball 3, the valve seat 4, the pressure ring 6, the valve seat stuffing 7, and the gasket 10 form an internal sealing structure.

[0060] In one embodiment, the ball valve also includes an actuator 14, a screw 16, a plug screw 17, a bracket 19, a bolt 20, a drive sleeve 21, and a joint 23. The bracket 19 is fixed on the stuffing box 26. The bracket 19 is a frame with a rectangular end face shape. A lower opening is opened on the lower plate of the frame. A pressure plate 25 is installed at the lower opening. The lower plate of the frame is provided with an escape opening for avoiding the drive sleeve 21. The actuator 14 is fixed on the upper plate of the frame. The actuator 14 is a motor, etc. The gland 12 is fixed to the stuffing box 26 by screws 16. The gland 12 is provided with a countersunk hole matching the screw 16. The pressure plate 25 is fixed to the gland 12 by bolts 20. A joint 23 is provided at the bottom of the jacket 24, and a plug screw 17 is installed at the joint 23.

[0061] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0062] 1. The valve body is a one-piece structure. The ball valve is a high-temperature, high-pressure hard-sealed floating jacket ball valve. It adopts a one-way sealing form with a simple structure to ensure overall sealing performance and stable switching operation functions.

[0063] 2. A butterfly spring is installed at the upstream end of the ball valve to provide pre-tightening force to the sealing surface of the valve seat 4 and the valve seat packing 7 to ensure the low-pressure sealing performance of the valve. The ball 3 and the valve seat 4 form a metal-to-metal hard seal to ensure the sealing performance of the valve under high temperature, high pressure, high freezing point organic matter and polymer working conditions.

[0064] 3. The ball valve welds the jacket 24 to the valve body 1 and uses 9 welds. The end flange is machined with threaded holes to connect with the pipeline. The high-temperature insulation medium is filled in the cavity 27 between the jacket 24 and the valve body 1, which overcomes the problem of the difficulty of heat preservation of the valve under high-temperature and high-pressure working conditions of organic matter and polymers with high freezing points.

[0065] 4. The end face of the valve cover 2 adopts a pentagonal tightening notch 201, which increases the contact surface when assembling the valve cover 2. The valve cover 2 is more resistant to extrusion, and a larger tightening force can be used to tighten the valve cover 2, thereby achieving quantitative compression of the gasket 10, ensuring high-pressure sealing between the valve body 1 and the valve cover 2, and overcoming the problem of difficult sealing of the high-pressure valve cover 2 of the insulation valve.

[0066] 5. Ball valves can be produced in series, suitable for high temperatures of 250℃-400℃, high pressures of 300-900LB, high freezing point organic matter and polymer working conditions, with considerable benefits.

[0067] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A ball valve, characterized in that: include: Valve body (1); A ball (3) is arranged inside the valve body (1); Two valve seats (4), respectively arranged on both sides of the sphere (3) and arranged inside the valve body (1); A stuffing box (26), one end of which is connected to the valve body (1); a valve stem (5), one end of which passes through the stuffing box (26) and is connected to the ball (3) and the other end of which extends out from the stuffing box (26); A gland (12) is arranged between the other end of the stuffing box (26) and the valve stem (5), wherein the gland (12) and the valve stem (5) form a receiving cavity which is open away from the valve body (1); A valve stem filler (11) is arranged in the accommodating cavity and away from the valve body (1); A packing pressing piece is sleeved on the valve stem (5) and fixed on the gland (12), and the packing pressing piece is suitable for pressing the valve stem packing (11) onto the gland (12).

2. The ball valve according to claim 1, characterized in that: An upper bearing (801) is provided between the packing pressure piece and the valve stem (5), and a lower bearing (802) is provided between the lower end of the valve stem (5), the valve body (1) and the packing box (26).

3. The ball valve according to claim 1 or 2, characterized in that: The valve stem (5) is provided with a step surface near the gland (12), and a thrust pad (15) is provided between the step surface and the gland (12).

4. The ball valve according to claim 1 or 2, characterized in that: The ball valve further comprises a valve cover (2), a pressure ring (6), a valve seat packing (7) and an elastic member (18); the valve cover (2) is connected to one end of the valve body (1); a valve seat (4) is located between the ball (3) and the valve cover (2); the pressure ring (6) is arranged between a side of the valve seat (4) facing away from the ball (3) and the valve cover (2); the pressure ring (6), the valve cover (2) and the valve seat (4) form a receiving annular cavity; the valve seat packing (7) is accommodated in the receiving annular cavity; the elastic member (18) is arranged between a side of the pressure ring (6) facing away from the ball (3) and the valve cover (2); and the end of the valve cover (2) facing away from the ball (3) has a tightening notch (201).

5. The ball valve according to claim 1 or 2, characterized in that: The packing pressing piece comprises a pressing sleeve (22) and a pressing plate (25), wherein the pressing sleeve (22) is arranged on the top of the valve stem packing (11), and the pressing plate (25) is arranged on the top of the pressing sleeve (22), and the pressing plate (25) is fixedly connected to the gland (12).

6. The ball valve according to claim 1 or 2, characterized in that: The sealing surfaces of the valve seat (4) and the ball (3) have a hard alloy layer.

7. The ball valve according to claim 6, characterized in that: The hard alloy layer is a chromium carbide layer or a Stellite alloy layer.

8. The ball valve according to claim 1 or 2, characterized in that: A jacket (24) is provided between the two end flanges of the valve body (1), and a through hole is provided on the jacket (24) for the stuffing box (26) to pass through. The jacket (24), the valve body (1) and the stuffing box (26) form a cavity (27), and the cavity (27) is filled with a heat-insulating medium.

9. The ball valve according to claim 8, characterized in that: Both ends of the jacket (24) are welded to the valve body (1), the jacket (24) is welded to the stuffing box (26), the stuffing box (26) is welded to the valve body (1), and side flanges (13) are welded to opposite sides of the jacket (24).

10. The ball valve according to claim 9, characterized in that The jacket (24) comprises two half-jacket bodies, and the two half-jacket bodies are welded.

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