A valve stem sealing structure and valve

Abstract

The present invention provides a valve stem sealing structure and a valve. The valve stem sealing structure includes a valve stem, a valve cover, and a universal seal ring. The valve includes a valve stem sealing structure. The valve cover is sleeved over the valve stem. The inner wall of the valve cover has a first annular groove, and a packing groove is provided between the outer wall of the valve stem and the inner wall of the valve cover. The universal seal ring is sleeved over the valve stem and located within the packing groove. This valve stem sealing structure, when used in a valve, eliminates the need for a pressure plate and a compression sleeve, resulting in a simple structure, space conservation, and a compact valve structure. The universal seal ring deforms under the force of the medium, and its inner and outer sides respectively contact the valve stem and the valve cover to achieve a seal between the valve stem and the valve cover. When installing the valve stem sealing structure, no pre-tightening force is required for the packing. When the valve stem performs rotational or linear motion, the friction torque of the valve stem is small, reducing the torque and power consumption during valve opening and closing. When the medium force is large, the universal seal ring is subjected to large force deformation, making the universal seal more reliable. The valve stem sealing structure can be used on a variety of valves.

Description

Technical Field

[0001] The present invention relates to the technical field of valve equipment, and in particular to a valve stem sealing structure and a valve. Background Art

[0002] Nowadays, society pays more and more attention to environmental protection. Many valves are required to meet low leakage requirements. However, the packing in the valve stem is easily damaged by the opening and closing of the valve stem, causing leakage, which is harmful to the environment, equipment and even life. Figure 1 As shown, the valve stem sealing structure in the prior art includes a packing 31, a packing pad 32, a pressure plate 22, a pressing sleeve 23, a stud and a nut 21, etc. The stud is passed through the pressure plate 22, the nut 21 is located above the pressure plate 22, and the packing 31 and the packing pad 32 are sleeved on the valve stem 1 and located on the lower side of the pressing sleeve 23.

[0003] When installing the valve, it is necessary to tighten the nut 21 so that the nut and stud apply downward pressure to the pressure plate 22 and the pressure sleeve 23. The pressure plate and the pressure sleeve compress the packing, which generates a top-down pre-tightening force on the packing, so that the packing presses against the outer wall of the valve stem and the inner wall of the stuffing box to achieve the sealing function. However, the packing pre-tightening force of the valve stem sealing structure with this structure is fixed during use. As the valve stem rotates or moves linearly, the graphite packing will gradually wear and loosen and cannot press against the outer wall of the valve stem and the inner wall of the stuffing box, causing the valve stem seal to fail and leak. Because the pressure the valve withstands in the experimental test state is much greater than the pressure in the actual working conditions, the pre-tightening force applied to the packing during valve installation is relatively large, resulting in the packing being squeezed too tightly against the outer wall of the valve stem and the inner wall of the stuffing box. The torque required for the valve stem to operate is relatively large, resulting in a large power consumption when the valve operates. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art that the valve stem sealing structure is prone to failure and leakage, and the power consumption required for valve operation is large.

[0005] To this end, the present invention provides a valve stem sealing structure, comprising

[0006] valve stem;

[0007] A valve cover is sleeved on the valve stem; a first annular groove is formed on the inner wall of the valve cover, and a packing groove is provided between the outer wall of the valve stem and the inner wall of the valve cover; the first annular groove and the valve stem are surrounded by the packing groove;

[0008] The sealing assembly includes a Variseal ring, which is sleeved on the valve stem and located in the stuffing groove.

[0009] Optionally, in the above-mentioned valve stem sealing structure, the sealing assembly further comprises a packing disposed in the packing groove, and the packing is disposed at an end of the pan-seal ring away from the bottom of the first annular groove.

[0010] Optionally, in the above-mentioned valve stem sealing structure, there is a gap between the packing and the pan seal ring.

[0011] Optionally, in the above-mentioned valve stem sealing structure, the packing is a V-type polytetrafluoroethylene packing.

[0012] Optionally, the above-mentioned valve stem sealing structure further includes a gland flange, which is sleeved on the outside of the valve stem and abuts against the valve cover; a first groove is provided on one end of the gland flange facing the valve cover, and a winding gasket is provided between the first groove and the valve cover, the upper surface of the winding gasket abuts against the bottom of the first groove, and the lower surface of the winding gasket abuts against the valve cover to form a seal between the gland flange and the valve cover.

[0013] Optionally, in the above-mentioned valve stem sealing structure, a second groove is provided on the inner wall surface of the gland flange facing the valve stem, and a first sealing ring is provided in the second groove; the inner side of the first sealing ring abuts against the valve stem, and the outer side of the first sealing ring abuts against the bottom of the second groove to form a seal between the valve stem and the gland flange.

[0014] Optionally, in the above-mentioned valve stem sealing structure, a second annular groove is provided on the inner wall surface of the end of the gland flange away from the valve cover, and a graphite ring is provided on the second annular groove, the inner side of the graphite ring abuts against the valve stem, and the outer side of the graphite ring abuts against the gland flange.

[0015] Optionally, in the valve stem sealing structure, a protrusion is provided at one end of the gland flange close to the valve cover, the protrusion extends into the packing groove, and the packing abuts against the protrusion.

[0016] Optionally, the above-mentioned valve stem sealing structure also includes a connecting flange arranged on the pressure cover flange, the connecting flange is sleeved on the outside of the valve stem, a third groove is provided on the inner wall surface of the connecting flange, a second sealing ring is provided in the third groove, the inner side of the second sealing ring abuts against the valve stem, and the outer side of the second sealing ring abuts against the bottom of the third groove.

[0017] The present invention also provides a valve, comprising the valve stem sealing structure as described above.

[0018] The technical solution of the present invention has the following advantages:

[0019] 1. The valve stem sealing structure provided by the present invention comprises a valve stem, a valve cover, and a vane ring. The valve cover is sleeved over the valve stem; a first annular groove is defined on the inner wall of the valve cover, and a packing groove is defined between the outer wall of the valve stem and the inner wall of the valve cover. The first annular groove and the valve stem enclose the packing groove. The vane ring is sleeved over the valve stem and positioned within the packing groove.

[0020] The stem sealing structure of this structure is applied to the valve, without the need for a pressure plate and a compression sleeve. It has a simple structure, saves space, makes the valve structure compact, and has multiple sealing effects, making the sealing safer and more reliable. The medium flowing in the valve body generates a medium force, which acts on the universal ring from bottom to top. The universal ring is deformed by the force, and its inner and outer sides respectively adhere to the valve stem and the valve cover to achieve the seal between the valve stem and the valve cover. At the same time, the packing at the valve stem is deformed by the thrust of the universal ring and squeezes the valve stem and the valve cover on both sides to achieve the seal. When installing the stem sealing structure, there is no need to apply pre-tightening force to the packing. When there is no medium flowing through the valve or When the amount of circulating medium is small, there is no medium force in the valve or the medium force is small. At the same time, the fit between the universal ring and the valve stem is not tight, and the friction between the two is small. When the valve stem makes rotational motion or linear motion, the friction torque of the valve stem is small, which reduces the torque when the valve is opened and closed, and reduces the power consumption of the valve opening and closing. When the medium force in the valve is large, the valve stem is more likely to leak, and the valve stem sealing performance requirements are higher. The large medium force causes the pressure on the universal ring to increase, and the deformation of the universal ring under stress increases. The inner and outer sides of the universal ring are more tightly abutted against the valve stem and valve cover, and the seal is more reliable. The valve stem sealing structure can be used on a variety of valves.

[0021] 2. The valve provided by the present invention includes a valve stem sealing structure. There is no need to set a pressure plate and a pressure sleeve in the valve. The structure is simple, space is saved, and the valve structure is compact. There is no need to apply pre-tightening force to the packing when the valve is installed. The valve stem friction torque and power consumption are small when the valve is opened and closed. The greater the medium pressure in the valve, the better the valve sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the valve stem sealing structure described in the background technology of the present invention;

[0024] Figure 2 It is a ball valve with a stem sealing structure;

[0025] Figure 3 for Figure 2 A partial enlarged view of the valve stem sealing structure in the middle part A;

[0026] Description of reference numerals:

[0027] 1-valve stem; 21-nut; 22-pressure plate; 23-pressing sleeve; 31-packing; 32-packing pad; 4-valve cover; 41-first annular groove; 5-packing groove; 6-sealing assembly; 61-Van Seal ring; 62-V-type PTFE packing; 63-wound gasket; 64-first sealing ring; 65-graphite ring; 66-second sealing ring; 7-cover flange; 71-protrusion; 8-connecting flange; 9-valve body. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Example 1

[0033] This embodiment provides a valve stem sealing structure, such as Figure 2 As shown, it includes a valve stem 1, a valve cover 4 and a valve ring 61.

[0034] Among them, the valve cover 4 is mounted on the outside of the valve stem 1; a first annular groove 41 is provided on the inner wall surface of the valve cover 4, and a packing groove 5 is provided between the outer wall of the valve stem 1 and the inner wall of the valve cover 4; the first annular groove 41 and the valve stem 1 are surrounded by the packing groove 5; the universal ring 61 is mounted on the valve stem 1 and is located in the packing groove 5.

[0035] The valve stem sealing structure of this structure is applied to the valve, and there is no need to set the pressure plate 22 and the pressure sleeve 23. The structure is simple, space-saving, and the valve structure is compact. The medium flowing in the valve body generates a medium force, which acts on the universal ring 61 from bottom to top. The universal ring 61 is deformed by the force, and its inner and outer sides respectively press against the valve stem 1 and the valve cover 4 to achieve a seal between the valve stem 1 and the valve cover 4. At the same time, the packing at the valve stem is deformed by the thrust of the universal ring and squeezes the valve stem and the valve cover on both sides to achieve a seal. When installing the valve stem sealing structure, there is no need to apply pre-tightening force to the packing. When there is no medium flowing through the valve or the amount of medium flowing through the valve is small, the valve There is no medium force in the valve or the medium force is small, the fit between the universal ring 61 and the valve stem 1 is not tight, and the friction between the two is small. When the valve stem 1 performs rotational motion or linear motion, the friction torque of the valve stem 1 is small, which reduces the torque during valve opening and closing and reduces the power consumption of the valve opening and closing. When the medium force in the valve is large, the valve stem 1 is more likely to leak, and the sealing performance requirements of the valve stem 1 are higher. The large medium force causes greater pressure on the universal ring 61, and the universal ring 61 is greatly deformed by the force. The inner and outer sides of the universal ring 61 are more tightly in contact with the valve stem 1 and the valve cover 4, and the seal is more reliable. The valve stem sealing structure can be used on various valves.

[0036] The PanSeal ring is an existing sealing element. It is a high-performance seal made of U-shaped polytetrafluoroethylene with a special spring inside. The appropriate spring force plus the system fluid pressure pushes the sealing lip (surface) out and gently presses the sealed metal surface to form a very excellent sealing effect.

[0037] Specifically, the outer wall of the valve stem 1 and the inner wall of the valve cover 4 are surrounded by a packing groove 5. The sealing assembly 6 also includes a packing, see Figure 1 The packing is positioned at the end of the Variseal ring 61 away from the bottom of the first annular groove 41. A vertical gap exists between the packing and the Variseal ring 61, and a gap exists between the Variseal ring 61 and the bottom of the first annular groove 41. These two gaps prevent the Variseal ring 61 and packing from being squeezed and deformed in the initial state, reducing the initial torque of the valve stem 1. As the medium force increases, the Variseal ring 61 and packing are squeezed and deformed, causing the torque of the valve stem 1 to gradually increase. Optimally, the packing is a V-shaped PTFE packing 62.

[0038] The valve stem sealing structure further includes a gland flange 7 and a connecting flange 8 ; the sealing assembly 6 further includes a spiral wound gasket 63 , a first sealing ring 64 , a graphite ring 65 and a second sealing ring 66 .

[0039] The gland flange 7 is sleeved on the outside of the valve stem 1 and its lower end face abuts against the valve cover 4. A first groove is provided on the lower end face of the gland flange 7 facing the valve cover 4. The wound gasket 63 is arranged between the first groove and the valve cover 4. The upper surface of the wound gasket 63 abuts against the bottom of the first groove, and the lower surface of the wound gasket 63 abuts against the valve cover 4 to form a seal between the lower end face of the gland flange 7 and the upper end face of the valve cover 4.

[0040] A second groove is provided on the inner wall surface of the gland flange 7 facing the valve stem 1, and the first sealing ring 64 is sleeved on the valve stem 1 and located in the second groove; the inner side of the first sealing ring 64 abuts against the valve stem 1, and the outer side of the first sealing ring 64 abuts against the bottom of the second groove to form a seal between the valve stem 1 and the gland flange 7. For example, the first sealing ring 64 is an O-ring.

[0041] See also Figure 3 A second annular groove is provided on the inner wall surface of the upper end of the gland flange 7 away from the valve cover 4. The graphite ring 65 is sleeved on the valve stem 1 and located in the second annular groove. The inner side of the graphite ring 65 abuts on the outer wall surface of the valve stem 1, and the outer side of the graphite ring 65 abuts on the gland flange 7.

[0042] When the medium flows through the valve body, medium force is generated in the valve body, and the medium force is from bottom to top ( Figure 3 The force (in the up and down directions) first acts on the Variseal ring 61. The Variseal ring 61 is deformed by the force and squeezes the valve stem 1 and the valve cover 4 on both sides to form a first seal. The Variseal ring 61 is deformed and pushes the V-type PTFE packing 62 upward. The V-type PTFE packing 62 is deformed by the force and squeezes the valve stem 1 and the valve cover 4 on both sides to form a second seal. The V-type PTFE packing 62 is forced to squeeze the gland flange 7 upward. The gland flange 7 squeezes the first sealing ring 64. The first sealing ring 64 is deformed by the force and squeezes the valve stem 1 and the gland flange 7 on both sides to form a third seal. The first sealing ring 64 squeezes the graphite ring 65 upward. The graphite ring 65 is deformed by the force and squeezes the valve stem 1 and the gland flange 7 on both sides to form a fourth seal.

[0043] When the medium force in the valve body is low, such as in low-temperature operating conditions, or when there is no medium force, the radial deformation of each sealing component 6 is minimal or non-existent. The sealing components 6 are not tightly pressed against the valve stem 1 or the valve cover on either side, resulting in low friction torque during valve stem 1 operation and low energy consumption. When the medium force in the valve body is high, the force exerted on the Variseal ring 61 is high, and the upward force exerted by the Variseal ring 61 on the V-PTFE packing 62 is also high. This causes significant radial deformation of the V-PTFE packing 62, making the seal at the V-PTFE packing 62 more secure. The sealing performance of the V-PTFE packing 62 can be dynamically adjusted in real time as the medium force in the valve body changes, resulting in excellent sealing performance.

[0044] The Variseal ring 61 and V-shaped PTFE packing 62 function as the primary seal under normal circumstances. If the Variseal ring 61 and V-shaped PTFE packing 62 fail, the first seal ring 64, graphite ring 65, and spiral wound gasket 63 act as secondary seals. The stem seal structure features multiple sealing elements, ensuring reliable sealing performance and preventing leakage of media within the valve.

[0045] In special circumstances, such as when the valve catches fire, the universal seal ring 61, the V-type PTFE packing 62 and the first sealing ring 64 are burned out and fail, while the graphite ring 65 and the spiral wound gasket 63 are fireproof and high temperature resistant, and can still play a sealing role in the event of a valve fire to prevent leakage of the medium.

[0046] Optimally, a protrusion 71 is provided at one end of the gland flange 7 close to the valve cover 4 , which extends into the packing groove 5 to make the gland flange 7 and the valve cover 4 fit more tightly, thereby increasing the sealing between the two; the top of the V-shaped PTFE packing 62 abuts against the protrusion 71 .

[0047] The connecting flange 8 is provided on the gland flange 7 and is sleeved on the outside of the valve stem 1. A third groove is provided on the inner wall of the connecting flange. The second sealing ring 66 is sleeved on the valve stem 1 and located in the third groove. The inner side of the second sealing ring 66 abuts against the valve stem 1, and the outer side of the second sealing ring 66 abuts against the bottom of the third groove. The second sealing ring 66 performs a sealing function between the valve stem 1 and the connecting flange. For example, the second sealing ring 66 is an O-ring.

[0048] As a first alternative embodiment to Example 1, the second sealing ring 66 can be omitted. As a further variation, the graphite ring 65, the first sealing ring 64, the spiral wound gasket 63, or all of the graphite ring 65, the first sealing ring 64, and the spiral wound gasket 63 can be omitted. Accordingly, the first groove, the second groove, and the second annular groove can be omitted. Only the Variseal ring 61 and the V-shaped PTFE packing 62 can be provided, as long as they provide effective sealing.

[0049] As a second alternative embodiment of Example 1, the protrusion 71 may not be provided on the end of the gland flange 7 close to the valve cover 4. The bottom end of the gland flange 7 may be flush with the top end of the valve cover 4, as long as the universal seal 61 and the V-type PTFE packing 62 can effectively seal.

[0050] As a third alternative implementation of Example 1, the filler material may also be carbon fiber or the like.

[0051] As a fourth alternative embodiment of Example 1, no gap may be left between the packing and the Variseal ring 61 along the length of the valve stem 1, or no gap may be left between the Variseal ring 61 and the packing, or neither gap may be provided. As long as the medium force exists in the valve body, the Variseal ring 61 can be deformed and squeeze the packing under the force, and a seal is formed between the Variseal ring 61 and the packing.

[0052] As a fifth alternative to Example 1, packing may be omitted, and only a Variseal ring 61 may be provided in the packing groove 5. When the medium pressure is applied to the Variseal ring 61, the Variseal ring 61 is deformed by the force, with its upper side abutting against the lower end surface of the gland flange 7 and its lower side abutting against the bottom of the first annular groove 41. The Variseal ring 61 then radially deforms and squeezes the valve stem 1 and valve cover 4 on both sides, forming a seal therebetween.

[0053] Example 2

[0054] This embodiment provides a ball valve, such as Figure 2 As shown, it includes a valve body 9 and the valve stem sealing structure in embodiment 1.

[0055] There is no need to set a pressure plate 22 and a pressure sleeve 23 in the ball valve, the structure is simple, space is saved, and the valve structure is compact; there is no need to apply pre-tightening force to the packing when the valve is installed, and the friction torque of the valve stem 1 is small and the power consumption is small when the valve is opened and closed; the greater the medium pressure in the valve, the better the valve sealing performance.

[0056] As a variation, the valve stem sealing structure in Example 1 can also be applied to other sealing structures, for example, it can also be applied to gate valves or butterfly valves.

[0057] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A valve stem sealing structure, characterized in that: include Valve stem (1); A valve cover (4) is sleeved on the outside of the valve stem (1); a first annular groove (41) is provided on the inner wall surface of the valve cover (4); a stuffing groove (5) is provided between the outer wall of the valve stem (1) and the inner wall of the valve cover (4); the first annular groove (41) and the valve stem (1) enclose the stuffing groove (5); A sealing assembly (6), wherein the sealing assembly (6) includes a universal seal ring (61), the universal seal ring (61) being sleeved on the outside of the valve stem (1) and located in the packing groove (5); the sealing assembly (6) also includes a packing arranged in the packing groove (5), the packing being arranged at an end of the universal seal ring (61) away from the bottom of the first annular groove (41), and the packing and the universal seal ring (61) being arranged adjacent to each other in the vertical direction; a gap is formed between the packing and the adjacent ends of the universal seal ring (61); and a gap exists between the universal seal ring (61) and the bottom of the first annular groove (41); A gland flange (7) and a connecting flange arranged on the gland flange (7), wherein the connecting flange is sleeved outside the valve stem (1), and the gland flange (7) is sleeved outside the valve stem (1) and abuts against the valve cover (4); a first groove is provided around one end of the gland flange (7) facing the valve cover (4), a winding gasket (63) is provided between the first groove and the valve cover (4), the upper surface of the winding gasket (63) abuts against the bottom of the first groove, and the lower surface of the winding gasket (63) abuts against the valve cover (4) to form a seal between the gland flange (7) and the valve cover (4).

2. The valve stem sealing structure according to claim 1, characterized in that: The filler is a V-shaped polytetrafluoroethylene filler (62).

3. The valve stem sealing structure according to claim 1 or 2, characterized in that: A second groove is provided on the inner wall surface of the gland flange (7) facing the valve stem (1), and a first sealing ring (64) is provided in the second groove; the inner side of the first sealing ring (64) abuts against the valve stem (1), and the outer side of the first sealing ring (64) abuts against the bottom of the second groove to form a seal between the valve stem (1) and the gland flange (7).

4. The valve stem sealing structure according to claim 1 or 2, characterized in that: A second annular groove is provided on the inner wall surface of one end of the gland flange (7) away from the valve cover (4), and a graphite ring (65) is provided on the second annular groove. The inner side of the graphite ring (65) abuts against the valve stem (1), and the outer side of the graphite ring (65) abuts against the gland flange (7).

5. The valve stem sealing structure according to claim 1 or 2, characterized in that: A protrusion (71) is provided on one end of the gland flange (7) close to the valve cover (4), the protrusion (71) extends into the packing groove, and the packing abuts against the protrusion (71).

6. The valve stem sealing structure according to claim 1 or 2, characterized in that: A third groove is provided on the inner wall surface of the connecting flange, and a second sealing ring (66) is provided in the third groove. The inner side of the second sealing ring (66) abuts against the valve stem (1), and the outer side of the second sealing ring (66) abuts against the bottom of the third groove.

7. A valve, characterized in that: The invention comprises a valve body (9) and a valve stem sealing structure according to any one of claims 1 to 6.

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