A valve shaft sealing structure and a butterfly valve including the sealing structure

Abstract

The present invention discloses a valve shaft sealing structure and a butterfly valve including the sealing structure, comprising a valve body, a driving device installed on the upper part of the valve body, an upper shaft hole opened in the valve body, an upper shaft sleeve arranged in the upper shaft hole, an upper valve shaft arranged in the upper shaft sleeve, a stuffing box arranged at the upper end of the upper shaft hole, a stuffing box arranged in the stuffing box, a receiving groove formed between the valve body and the driving device, a stuffing pressure plate movable along the axial direction of the upper valve shaft arranged in the receiving groove, an adjusting screw arranged on the stuffing pressure plate, and a first nut threadedly connected to the adjusting screw after passing through the valve body. The stuffing pressure plate can move up and down in the receiving groove, and the pressure state of the stuffing can be adjusted by rotating the first nut to obtain sufficient sealing pressure ratio. A lifting screw is threadedly connected to the valve body, the upper end of the lifting screw abuts against the driving device, and the lower end extends out of the valve body. The driving device can be easily lifted by screwing in the lifting screw, and sufficient open space for adjusting and replacing the stuffing can be conveniently obtained without removing the driving device.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and in particular to a valve shaft sealing structure and a butterfly valve comprising the sealing structure. Background Art

[0002] The butterfly valve needs to design and set a sealing structure at the end of the upper valve shaft 4 extending outside the valve body 2 so that the medium will not flow out when the upper valve shaft 4 is stationary or rotating. There are two main existing technical solutions. Figure 1-4 As shown, a packing box is arranged on the valve body 2, a packing gland 19 is connected to the valve body 2 using a connecting piece such as a stud, and packing 7, packing pad 17, etc. are pressed and fixed in the packing box. The packing 7 is squeezed and limited by the packing gland 19 to produce elastic deformation, so that a certain sealing pressure ratio is established between the inner wall of the packing box and the contact surface of the upper valve shaft 4, which has a sealing effect of preventing the outflow of the medium. In order to repair and replace the packing 7, a transmission bracket 20 with a window is arranged near the packing gland 19 between the upper flange of the valve body 2 and the driving device 1, and the driving device 1, the transmission bracket 20 and the valve body 2 are connected by a connecting bolt assembly 18. The advantage of this technical solution is that the channel and operating space for maintaining and replacing the packing 7 can be established through the window without disassembling the driving device 1. The disadvantage is that there are many parts (mainly an additional transmission bracket 20), which causes the valve to have a larger axial dimension along the valve shaft, occupy a larger space, and have a poor stress state.

[0003] Prior art solution 2 is as follows Figure 5 and Figure 6 As shown, the main body is not drawn, only the stuffing box part is drawn. A cylindrical stuffing rack 21 is arranged in the stuffing box, an inner O-ring groove is arranged on the inner wall of the cylindrical stuffing rack 21, and an outer O-ring groove is arranged on the outer wall of the cylindrical stuffing rack 21. Inner O-rings and outer O-rings constituting motion sealing and static sealing functions are respectively installed in the inner O-ring groove and the outer O-ring groove. The inner O-ring and the outer O-ring after being squeezed and deformed respectively make the stuffing rack and the surface of the upper valve shaft 4 and the inner wall of the stuffing box form a motion sealing and static sealing structure, thereby preventing the medium from flowing out. The advantages of this technical solution are that there are fewer parts (no transmission bracket), saving materials, and occupying less space. The disadvantage is that the drive device 1 needs to be removed when replacing the stuffing, which brings inconvenience to the maintenance and replacement of the stuffing.

[0004] In addition, another common disadvantage of the above two prior art solutions is that there is no valve shaft anti-escape structure. Therefore, when the upper valve shaft 4 is under internal pressure and the drive device 1 is completely removed, the valve shaft is likely to escape from the valve body 2 (when the valve shaft breaks or the connecting pin 7 between the valve shaft and the butterfly plate is missing or fails), causing an accident. Summary of the invention

[0005] The object of the present invention is to provide a valve shaft sealing structure and a butterfly valve including the sealing structure in view of the above-mentioned deficiencies in the prior art.

[0006] To solve the above problems, the technical solution adopted by the present invention is:

[0007] A valve shaft sealing structure includes a valve body, a driving device is installed on the upper part of the valve body through a connecting bolt assembly, an upper shaft hole is opened in the valve body, an upper shaft sleeve is arranged in the upper shaft hole, an upper valve shaft is arranged in the upper shaft sleeve, the upper end of the upper valve shaft is connected to the driving device, the lower end of the upper valve shaft is connected to the butterfly plate, a stuffing box is arranged at the upper end of the upper shaft hole, stuffing is arranged in the stuffing box, a receiving groove is formed between the valve body and the driving device, a packing pressure plate which can move axially along the upper valve shaft is arranged in the receiving groove, an adjusting screw is arranged on the packing pressure plate, and the adjusting screw passes through the valve body and is threadedly connected to a first nut.

[0008] A further technical solution is that a lifting screw is threadedly connected to the valve body, the upper end of the lifting screw abuts against the driving device, and the lower end extends out of the valve body.

[0009] A further technical solution is that a second nut is threadedly connected to the jacking screw, and a spring washer is sleeved on the jacking screw, and the spring washer is located between the valve body and the second nut.

[0010] A further technical solution is that an anti-escape pressure ring is fixedly provided at the bottom of the stuffing box, and the anti-escape pressure ring is pressed on the shoulder of the upper valve shaft.

[0011] A further technical solution is that at least two grooves are provided at the lower part of the upper shaft hole, the grooves are located below the upper shaft sleeve, and O-rings are provided in the grooves.

[0012] A further technical solution is that a butterfly spring is sleeved on the adjusting screw, and the butterfly spring is located between the nut and the valve body.

[0013] A further technical solution is that the filler is a filler with a round cross section or a special-shaped cross section.

[0014] Also disclosed is a butterfly valve comprising the valve shaft sealing structure as described above.

[0015] The beneficial effects of adopting the above technical solution are:

[0016] The elastic deformation caused by the O-ring in contact with the upper valve shaft forms the first seal on the upper valve shaft to prevent the internal medium from flowing out. The second seal on the upper valve shaft is formed by setting a stuffing box and the stuffing pad, stuffing and stuffing pressure plate in the stuffing box to prevent the medium in the valve body from flowing out through the gap between the upper valve shaft and the valve body.

[0017] Use screws to connect the anti-dropout ring to the lower end of the valve body stuffing box and fix them together. The inner edge of the anti-dropout ring contacts the upper valve shaft shoulder. When the drive device is completely removed, the upper valve shaft will not be axially displaced or fall out of the valve body due to internal pressure, thus avoiding accidents caused by the upper valve shaft falling out due to force.

[0018] The packing pressure plate can move up and down in the accommodating groove, and the pressure state of the packing can be adjusted by rotating the first nut on the adjusting screw to obtain sufficient sealing specific pressure.

[0019] A jacking screw is threadedly connected to the valve body, the upper end of which abuts against the drive device, and the lower end extends out of the valve body. Screwing in the jacking screw can easily jack up the drive device, so that the drive device moves away from the valve body, and sufficient open space for adjusting and replacing packing can be easily obtained without removing the drive device. The jacking screw can be locked by the second nut and spring washer on the jacking screw to prevent it from loosening.

[0020] The drive device is directly connected to the upper flange of the valve body by a connecting bolt assembly, eliminating the transmission bracket in the traditional structure. The length dimension along the valve axis is small, the external structure of the butterfly valve is compact, and the space occupied is small, saving materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of prior art solution 1;

[0022] Figure 2 It is a structural schematic diagram of another direction of the prior art solution 1;

[0023] Figure 3 yes Figure 1 Enlarged view of part A in the middle;

[0024] Figure 4 Yes Yes Figure 3 Enlarged view of middle part B;

[0025] Figure 5 It is a structural schematic diagram of prior art solution 2;

[0026] Figure 6 yes Figure 5 Enlarged view of the middle C part;

[0027] Figure 7 It is a structural schematic diagram of the valve shaft sealing structure of the present invention;

[0028] Figure 8 yes Figure 7 Enlarged view of the middle D part;

[0029] Fig. 9 yes Figure 7 Enlarged view of the middle E part;

[0030] Fig.10 yes Fig. 9 Enlarged view of the middle F part;

[0031] Fig.11 It is a structural schematic diagram of the butterfly valve of the present invention.

[0032] In the figure: 1. drive device; 2. valve body; 3. upper shaft sleeve; 4. upper valve shaft; 5. butterfly plate; 6. O-ring; 7. packing; 8. receiving groove; 9. packing pressure plate; 10. adjusting screw; 11. first nut; 12. butterfly spring; 13. lifting screw; 14. second nut; 15. spring washer; 16. anti-slip pressure ring; 17. packing pad; 18. connecting bolt assembly; 19. packing gland; 20. transmission bracket; 21. cylindrical packing rack. DETAILED DESCRIPTION

[0033] The following embodiments of the present invention are described in further detail in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0034] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and 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 cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0035] like Figure 7-10As shown, a valve shaft sealing structure includes a valve body 2, a driving device 1 is installed on the upper part of the valve body 2 through a connecting bolt assembly 18, an upper shaft hole is opened in the valve body 2, an upper shaft sleeve 3 is arranged in the upper shaft hole, an upper valve shaft 4 is arranged in the upper shaft sleeve 3, the upper end of the upper valve shaft 4 is connected to the driving device 1, and the lower end of the upper valve shaft 4 is connected to the butterfly plate 5, at least two grooves are arranged in the lower part of the upper shaft hole, the grooves are located below the upper shaft sleeve 3, and an O-ring 6 is arranged in the groove. The elastic deformation generated by the O-ring 6 after contacting the upper valve shaft 4 constitutes the first seal of the upper valve shaft to prevent the internal medium from flowing out. A stuffing box is provided at the upper end of the upper shaft hole, and a stuffing box is provided with a stuffing 7. A receiving groove 8 is formed between the valve body 2 and the driving device 1. A stuffing pressure plate 9 that can move axially along the upper valve shaft 4 is provided in the receiving groove 8. An adjusting screw 10 is provided on the stuffing pressure plate 9. The adjusting screw 10 passes through the valve body 2 and is threadedly connected with a first nut 11. A butterfly spring 12 is also sleeved on the adjusting screw 10, and the butterfly spring 12 is located between the first nut 11 and the valve body 2. The stuffing pressure plate 9 is restricted by the adjusting screw 10 and the first nut 11 to press the stuffing, and together constitutes the second seal of the upper valve shaft to prevent the internal medium from flowing out. The pressure state of the stuffing is adjusted by rotating the first nut 11 on the adjusting screw 10 to obtain sufficient sealing specific pressure. The driving device 1 is directly connected to the upper flange of the valve body 2 using a connecting bolt assembly 18, and the transmission bracket in the traditional structure is eliminated. The length dimension along the valve shaft direction is small, the external structure of the butterfly valve is compact, and the space occupied is small, saving materials.

[0036] The valve body 2 is provided with a threaded hole parallel to the axial direction of the upper valve shaft 4, and a jacking screw 13 is threadedly connected in the threaded hole. The upper end of the jacking screw 13 abuts against the driving device 1, and the lower end extends out of the valve body 2 and is threadedly connected with a second nut 14. A spring washer 15 is also sleeved on the jacking screw 13, and the spring washer 15 is located between the valve body 2 and the second nut 14. When it is necessary to replace or adjust the packing, loosen the connecting bolt assembly 18 so that the driving device 1 can move axially along the upper valve shaft 4, and screw in the jacking screw 13 to conveniently jack up the driving device 1 so that the driving device 1 moves away from the valve body. It is not necessary to remove the driving device 1, and it is convenient to obtain sufficient open space for adjusting and replacing the packing. The jacking screw 13 can be locked by the second nut 14 and the spring washer 15 on the jacking screw 13, so that it will not loosen during the working process.

[0037] The upper valve shaft 4 is a stepped valve shaft, and an anti-escape pressure ring 16 is fixed to the bottom of the stuffing box by screws. The anti-escape pressure ring 16 is pressed on the shoulder of the upper valve shaft 4. The inner diameter of the anti-escape pressure ring 16 and the outer diameter of the corresponding part of the upper valve shaft 4 are clearance-matched, which can limit the movement of the upper valve shaft toward the outside of the valve body 2 without affecting the rotation of the valve shaft. When the drive device 1 is completely removed, the upper valve shaft 4 will not produce axial displacement and escape from the valve body 2 due to internal pressure. A packing pad 17 is also provided above the anti-escape pressure ring 16, and the packing pad 17 is located between the packing 6 and the anti-escape pressure ring 16.

[0038] The packing 7 is a round or shaped packing. Using a round or shaped packing that is much larger than a standard packing has a good sealing effect and is conducive to extending the service life of the packing. In addition, the change in packing compression caused by the internal pressure or temperature change of the valve body pipeline has little effect on the sealing of the packing.

[0039] Also disclosed is a butterfly valve, such as Fig.11 As shown, it includes the valve shaft sealing structure mentioned above.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A valve shaft sealing structure, characterized in that: The valve body (2) comprises a valve body (2), the upper part of which is provided with a driving device (1) via a connecting bolt assembly (18), an upper shaft hole is provided in the valve body (2), an upper shaft sleeve (3) is provided in the upper shaft hole, an upper valve shaft (4) is provided in the upper shaft sleeve (3), the upper end of the upper valve shaft (4) is connected to the driving device (1), the lower end of the upper valve shaft (4) is connected to the butterfly plate (5), a stuffing box is provided at the upper end of the upper shaft hole, a stuffing box is provided with a stuffing (7), a receiving groove (8) is formed between the valve body (2) and the driving device (1), a stuffing pressure plate (9) which can move axially along the upper valve shaft (4) is provided in the receiving groove (8), an adjusting screw (10) is provided on the stuffing pressure plate (9), and the adjusting screw (10) passes through the valve body (2) and is threadedly connected to a first nut (11); A lifting screw (13) is threadedly connected to the valve body (2), the upper end of the lifting screw (13) abuts against the driving device (1), and the lower end extends out of the valve body (2); The jacking screw (13) is threadedly connected with a second nut (14), and a spring washer (15) is sleeved on the jacking screw (13), wherein the spring washer (15) is located between the valve body (2) and the second nut (14); An anti-escape pressure ring (16) is fixedly arranged at the bottom of the stuffing box, and the anti-escape pressure ring (16) is pressed on the shoulder of the upper valve shaft (4).

2. A valve shaft sealing structure according to claim 1, characterized in that: At least two grooves are provided at the lower part of the upper shaft hole, the grooves are located below the upper shaft sleeve (3), and O-rings (6) are provided in the grooves.

3. A valve shaft sealing structure according to claim 1, characterized in that: The adjusting screw rod (10) is also sleeved with a butterfly spring (12), and the butterfly spring (12) is located between the nut and the valve body (2).

4. A valve shaft sealing structure according to claim 1, characterized in that: The filler (7) is a filler with a round cross section or a special-shaped cross section.

5. A butterfly valve, characterized in that: It comprises a valve shaft sealing structure as described in any one of claims 1 to 4.

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