WO2021169545A1

WO2021169545A1 - Valve stem sealing structure and valve

Info

Publication number: WO2021169545A1
Application number: PCT/CN2020/139614
Authority: WO
Inventors: 涂楠; 高仁杰
Original assignee: 苏州纽威阀门股份有限公司
Priority date: 2020-02-26
Filing date: 2020-12-25
Publication date: 2021-09-02
Also published as: CN111255945A

Abstract

A valve stem sealing structure and a valve. The valve stem sealing structure comprises a valve stem (1), a valve cover (4), and a spring seal (61). The valve comprises the valve stem sealing structure. The valve cover (4) is sleeved outside the valve stem (1). The inner wall surface of the valve cover (4) is provided with a first annular groove (41), and a filler groove (5) is provided between the outer wall of the valve stem (1) and the inner wall of the valve cover (4). The spring seal (61) is sleeved on the valve stem (1) and located in the filler groove (5). By applying this valve stem sealing structure to a valve, there is no need to provide a pressing plate and a pressing sleeve, thus the structure is simple, the space is saved, and the valve is compact in structure. The spring seal (61) is deformed by medium force so that the inner side and the outer side thereof respectively abut against the valve stem (1) and the valve cover (4) to implement the sealing between the valve stem (1) and the valve cover (4). There is no need to first apply a pre-tightening force to the filler when installing the valve stem sealing structure, and the friction torque of the valve stem (1) is low during the rotary motion or linear motion of the valve stem (1), thus the torque of the valve during opening and closing is reduced, and the opening and closing power consumption of the valve is decreased. Since large medium force leads to large force deformation of the spring seal (61), the sealing of the spring seal (61) is more reliable. The valve stem sealing structure can be used on a variety of valves.

Description

Stem sealing structure and valve

Technical field

The invention relates to the technical field of valve equipment, in particular to a valve stem sealing structure and a valve.

Background technique

Now society is paying more and more attention to environmental protection. Many valves are required to meet low leakage requirements, and the packing at the valve stem can easily cause damage to the packing due to the opening and closing of the valve stem, resulting in leakage, which is harmful to the environment, equipment and even life. As shown in Figure 1, the valve stem sealing structure in the prior art includes a packing 31, a packing pad 32, a pressure plate 22, a pressure sleeve 23, a stud and a nut 21, etc. The stud passes through the pressure plate 22, and the nut 21 is located on the pressure plate. Above 22, the packing 31 and the packing pad 32 are sleeved on the valve stem 1 and located on the lower side of the pressure sleeve 23.

When installing the valve, it is necessary to tighten the nut 21 so that the nut and stud exert downward pressure on the pressure plate 22 and the pressure sleeve 23. The pressure plate and the pressure sleeve compress the packing to produce a top-down pre-tightening force on the packing, so that the packing can compress the valve stem. The outer wall and the inner wall of the stuffing box achieve the function of sealing. However, the valve stem sealing structure of this structure has a fixed packing pre-tightening force during use. As the valve stem rotates or moves linearly, the graphite packing will gradually wear and relax and cannot compress the outer wall of the stem and the inner wall of the stuffing box, resulting in the valve Stem seal fails and leaks; because the valve bears a much greater pressure in the experimental test state than in the actual working condition, the pre-tightening force applied to the packing is greater when the valve is installed, causing the packing to squeeze the outer wall of the stem and the inner wall of the stuffing box Too tight, the torque required for valve stem action is larger, resulting in larger power consumption during valve action.

Summary of the invention

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

To this end, the present invention provides a valve stem sealing structure, including

Stem

The valve cover is sleeved outside the valve stem; the inner wall of the valve cover has a first annular groove, and a packing groove is arranged between the outer wall of the valve stem and the inner wall of the valve cover; the first ring The groove and the valve stem are enclosed to form the packing groove;

A sealing assembly, the sealing assembly includes a pan-plug ring, the pan-plug ring is sleeved on the valve stem and located in the packing groove.

Optionally, in the above-mentioned valve stem sealing structure, the sealing assembly further includes a packing arranged in the packing groove, and the packing is arranged at an end of the pan-plug ring away from the groove bottom of the first annular groove.

Optionally, in the valve stem sealing structure described above, there is a gap between the packing and the pan-plug ring.

Optionally, in the above-mentioned valve stem sealing structure, the packing is a V-shaped tetrafluoroethylene packing.

Optionally, the above-mentioned valve stem sealing structure further includes a gland flange, the gland flange is sleeved on the valve stem and abuts on the valve cover; the gland flange faces the One end of the valve cover is provided with a first groove, a winding pad is arranged between the first groove and the valve cover, and the upper surface of the winding pad abuts against the bottom of the first groove , The lower surface of the winding gasket abuts against the valve cover to form a seal between the gland flange and the valve cover.

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 a 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.

Optionally, in the above-mentioned valve stem sealing structure, a second annular groove is provided on the inner wall surface of one 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 on the valve stem, and the outer side of the graphite ring abuts on the gland flange.

Optionally, in the valve stem sealing structure described above, the gland flange is provided with a protruding portion at one end close to the valve cover, and the protruding portion extends into the packing groove, and the packing abuts against the The protrusions on.

Optionally, the above-mentioned valve stem sealing structure further includes a connecting flange arranged on the gland flange, the connecting flange is sleeved outside the valve stem, and the inner wall of the connecting flange is arranged There is a third groove, a second sealing ring is arranged in the third groove, the inner side of the second sealing ring abuts on the valve stem, and the outer side of the second sealing ring abuts on the The bottom of the third groove.

The present invention also provides a valve including the valve stem sealing structure as described in any one of the above.

The technical scheme of the present invention has the following advantages:

1. The valve stem sealing structure provided by the present invention includes a valve stem, a valve cover and a pan-plug ring, wherein the valve cover is sleeved outside the valve stem; the inner wall of the valve cover has a first annular groove, the outer wall of the valve stem and the valve A packing groove is arranged between the inner wall of the cover; the first annular groove and the valve stem are enclosed to form the packing groove. The pan plug ring is sleeved on the valve stem and located in the packing groove.

The stem sealing structure of this structure is applied to the valve without the need to set the pressure plate and the pressure sleeve, the structure is simple, and the space is saved, making the valve structure compact; the medium circulating in the valve body generates medium force, which acts on the pan from bottom to top. The plug ring and the pan plug ring are deformed by force. The inner and outer sides of the plug ring are respectively attached 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 and squeezed by the thrust of the pan plug ring. The side stem and the bonnet are sealed; when installing the stem sealing structure, there is no need to pre-tighten the packing. When the valve has no flowing medium or a small amount of flowing medium, there is no medium force in the valve or the medium force is small, and at the same time The plug ring and the valve stem are not closely attached, and the friction between the two is small. The friction torque of the valve stem is small when the valve stem rotates or moves linearly, which reduces the torque when the valve is opened and closed, and reduces the power consumption of the valve. ; When the medium force in the valve is larger, the valve stem is easier to leak, and the sealing performance of the valve stem is higher; the medium force makes the pressure on the pan plug ring greater, and the pan plug ring is deformed by force. The inner and outer sides of the stopper ring have a tighter contact with the valve stem and bonnet, and the seal is more reliable; the valve stem sealing structure can be used on a variety of valves.

2. The valve provided by the present invention includes a valve stem sealing structure. The valve does not need to be equipped with a pressure plate and a pressure sleeve. The valve has a simple structure, saves space, and has a compact valve structure. When the valve is installed, there is no need to apply pretension to the packing first. The valve is opened and closed. Rod friction torque is small, power consumption is small; the greater the pressure of the medium in the valve, the better the valve sealing performance.

Description of the drawings

In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the specific embodiments or the description of the prior art. Obviously, the appendix in the following description The drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

FIG. 1 is a schematic diagram of the valve stem sealing structure described in the background art of the present invention;

Figure 2 shows a ball valve with a stem sealing structure;

Fig. 3 is a partial enlarged view of the valve stem sealing structure of part A in Fig. 2;

Description of reference signs:

1-valve stem; 21-nut; 22-press plate; 23-press sleeve; 31-packing; 32-packing pad; 4-bonnet; 41-first annular groove; 5-packing groove; 6-seal component; 61-Pan plug ring; 62-V type tetrafluoride packing; 63-wound gasket; 64-first sealing ring; 65-graphite ring; 66-second sealing ring; 7-gland flange; 71-protrusion ; 8-Connecting flange; 9-Valve body.

Detailed ways

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

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the pointed device or element must have a specific orientation or a specific orientation. The structure and operation cannot therefore be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance.

In the description of the present invention, it should be noted that the terms "installed", "connected", and "connected" should be understood in a broad sense unless otherwise clearly specified and limited. For example, they can be fixed or detachable. Connected or integrally connected; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above-mentioned terms in the present invention can be understood in specific situations.

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.

Example 1

This embodiment provides a valve stem sealing structure, as shown in FIG. 2, which includes a valve stem 1, a valve cover 4 and a pan-plug ring 61.

Among them, the valve cover 4 is sleeved outside the valve stem 1; the inner wall of the valve cover 4 has a first annular groove 41, and a packing groove 5 is arranged between the outer wall of the valve stem 1 and the inner wall of the valve cover 4; the first annular groove 41 The valve stem 1 is surrounded by a packing groove 5; the pan plug ring 61 is sleeved on the valve stem 1 and is located in the packing groove 5.

The valve stem sealing structure of this structure is used in the valve, without the need to set the pressure plate 22 and the pressure sleeve 23, the structure is simple, saves space, and makes the valve structure compact; the medium circulating in the valve body generates medium force, which acts from bottom to top As for the pan-plug ring 61, the pan-plug ring 61 is deformed by force, and its inner and outer sides are respectively attached to the valve stem 1 and the valve cover 4 to achieve the seal between the valve stem 1 and the valve cover 4. At the same time, the packing at the valve stem is affected by the pan-plug ring The thrust of the valve deforms and squeezes the valve stem and bonnet on both sides to achieve sealing; there is no need to pre-tighten the packing when installing the valve stem sealing structure. When the valve has no flowing medium or a small amount of flowing medium, there is no medium force in the valve Or the medium force is small, the fitting between the pan-plug ring 61 and the valve stem 1 is not tight, the friction between the two is small, and the friction torque of the valve stem 1 is small when the valve stem 1 rotates or moves linearly, which reduces the valve opening. The closing torque reduces the power consumption of 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 of the valve stem 1 is higher; the large medium force makes the pan-plug ring 61 suffer The greater the pressure, the greater the force and deformation of the pan-plug ring 61, the inner and outer sides of the pan-plug ring 61 abut the valve stem 1 and the valve cover 4 tighter, and the seal is more reliable; the valve stem sealing structure can be used on a variety of valves.

The pan stopper ring is an existing sealing element. It is a U-shaped PTFE high-performance seal with a special spring inside. The sealing lip (surface) is pushed out and lightened by the appropriate spring force and the system fluid pressure. Lightly press the sealed metal surface to form a very good sealing effect.

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 FIG. 1. The packing is arranged at the end of the pan-plug ring 61 away from the bottom of the first annular groove 41. There is a vertical gap between the packing and the pan-plug ring 61. The pan-plug ring 61 and the second ring There is a gap at the bottom of an annular groove 41. The two gaps are arranged so that in the initial state, the pan-plug ring 61 and the packing will not be squeezed and deformed, reducing the initial torque of the valve stem 1; when the medium force increases, the pan The plug ring 61 and the packing are squeezed and deformed, and the torque of the valve stem 1 gradually increases. Optimally, the filler is a V-shaped tetrafluoroethylene filler 62.

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

The gland flange 7 is sleeved outside the valve stem 1, and its lower end abuts against the valve cover 4. The gland flange 7 faces the lower end of the valve cover 4 with a first groove, and the winding pad 63 is arranged on the first groove. Between a 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 on the valve cover 4 so as to be on the lower end surface of the gland flange 7. A seal is formed with the upper end surface of the valve cover 4.

The gland flange 7 is provided with a second groove on the inner wall surface of the valve stem 1, and the first sealing ring 64 is sleeved on the valve stem 1 and is located in the second groove; the inner side of the first sealing ring 64 and the valve stem 1 abutting, 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.

3, the inner wall of the upper end of the gland flange 7 away from the valve cover 4 is provided with a second annular groove, and the graphite ring 65 is sleeved on the valve stem 1 and is located in the second annular groove. The inner side 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.

When the valve body circulates the medium, a medium force is generated in the valve body. The medium force from bottom to top (up and down direction in Figure 3) first acts on the pan-plug ring 61. The pan-plug ring 61 is forced to deform and squeeze the valves on both sides. The stem 1 and the valve cover 4 form the first seal; the pan-plug ring 61 deforms and pushes upwards to squeeze the V-shaped PTFE packing 62, and the V-shaped PTFE packing 62 is forced to deform and squeeze the valve stem 1 and the valve cover 4 on both sides to form The second seal; the V-shaped PTFE packing 62 is forced to squeeze the gland flange 7 upward, the gland flange 7 squeezes the first sealing ring 64, and the first sealing ring 64 is forced to deform and squeeze the valve stems on both sides 1 and gland flange 7 form a third seal; the first sealing ring 64 squeezes the graphite ring 65 upward, and the graphite ring 65 is deformed and squeezed on both sides of the valve stem 1 and gland flange 7 to form a fourth seal .

When the medium force in the valve body is small, such as under low temperature conditions, or when there is no medium force, the radial deformation of each sealing assembly 6 is small or not deformed, and the sealing assembly 6 does not squeeze tightly with the valve stem 1 or the valve cover on both sides When the valve stem 1 moves, the frictional torque is small and the energy consumption is low; when the medium force in the valve body is large, the pan-plug ring 61 receives a large force, and the pan-plug ring 61 pushes up the V-shaped PTFE packing 62 with a large force. The PTFE packing 62 deforms greatly in the radial direction, and the sealing effect of the V-shaped tetrafluoro packing 62 is more reliable. The sealing performance of the V-shaped tetrafluoroethylene packing 62 can be dynamically adjusted in real time with the change of the medium force in the valve body, and the sealing performance is good.

The pan-plug ring 61 and the V-shaped tetrafluoroethylene packing 62 as the main seal play a sealing role under normal conditions. When the pan-plug ring 61 and the V-shaped PTFE packing 62 fail to seal, the first sealing ring 64, the graphite ring 65 and the winding gasket 63 serves as an auxiliary seal after the main seal fails. The stem sealing structure has multiple seals with reliable sealing performance to prevent leakage of the medium in the valve.

In special circumstances, such as when the valve catches fire, the pan-plug ring 61, the V-shaped PTFE packing 62 and the first sealing ring 64 are burnt out and fail. The graphite ring 65 and the winding gasket 63 are fire-resistant and high-temperature resistant, and they can still work when the valve catches fire. To the sealing effect, prevent the medium from leaking.

Optimally, one end of the gland flange 7 close to the bonnet 4 is provided with a protruding portion 71, which extends into the packing groove 5 so that the gland flange 7 and the bonnet 4 are more closely matched, increasing the difference between the two The sealing performance between the V-shaped tetrafluoroethylene filler 62 abuts on the protrusion 71.

The connecting flange 8 is arranged on the gland flange 7, the connecting flange is sleeved outside the valve stem 1, the inner wall of the connecting flange is provided with a third groove, and the second sealing ring 66 is sleeved on the valve stem 1 and is located In the third groove, the inner side of the second sealing ring 66 abuts on the valve stem 1, the outer side of the second sealing ring 66 abuts on the bottom of the third groove, and the second sealing ring 66 is connected to the stem 1 and Play a sealing role between the flanges. For example, the second sealing ring 66 is an O-ring.

As a first alternative implementation of Embodiment 1, the second sealing ring 66 may not be provided. As a further modification, the graphite ring 65 may not be provided, or the first sealing ring 64 may not be provided, or the winding gasket 63 may not be provided, or the graphite ring 65, the first sealing ring 64 and the winding gasket 63 may not be provided, and accordingly may not be provided. A first groove, a second groove, and a second annular groove are provided. Only the pan stopper ring 61 and the V-shaped tetrafluoroethylene packing 62 are provided, and the pan stopper ring 61 and the V-type tetrafluoroethylene packing 62 can effectively seal.

As a second alternative implementation of Embodiment 1, the end of the gland flange 7 close to the valve cover 4 may not be provided with the protrusion 71. The bottom end of the gland flange 7 can be flush with the top end of the valve cover 4, as long as the pan plug ring 61 and the V-shaped tetrafluoroethylene packing 62 can be effectively sealed.

As a third alternative implementation of Example 1, the filler material can also be carbon fiber or the like.

As a fourth alternative embodiment of Example 1, there may be no gap between the packing and the pan-plug ring 61 in the length direction of the valve stem 1, or there may be no gap between the pan-plug ring 61 and the packing, or two No gap is provided, as long as there is a medium force in the valve body, the pan-plug ring 61 can deform and squeeze the packing under the force, and the pan-plug ring 61 and the packing form a seal.

As a fifth alternative embodiment of Example 1, it is also possible not to provide a filler, and only a pan-plug ring 61 is provided in the filler groove 5. When the pan-plug ring 61 is subjected to medium pressure, the pan-plug ring 61 deforms its upper side under force. Abutting on the lower end surface of the gland flange 7, the lower side abutting on the bottom of the first annular groove 41, the pan-plug ring 61 is radially deformed and squeezes the valve stem 1 and the valve cover 4 on both sides between the two Just form a seal.

Example 2

This embodiment provides a ball valve, as shown in FIG. 2, which includes a valve body 9 and the valve stem sealing structure in the first embodiment.

The ball valve does not need to set the pressure plate 22 and the pressure sleeve 23, the structure is simple, the 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. When the valve is opened and closed, the friction torque of the valve stem 1 is small and the power consumption is small; The greater the medium pressure, the better the valve sealing performance.

As a modification, the valve stem sealing structure in Embodiment 1 can also be applied to other sealing structures, for example, it can also be applied to gate valves or butterfly valves.

Obviously, the above-mentioned embodiments are merely examples for clear description, and are not intended to limit the implementation manners. For those of ordinary skill in the art, other changes or modifications in different forms can be made on the basis of the above description. It is unnecessary and impossible to list all the implementation methods here. The obvious changes or changes derived from this are still within the protection scope created by the present invention.

Claims

A valve stem sealing structure, which is characterized in that it comprises

Valve stem (1);

The valve cover (4) is sleeved outside the valve stem (1); the inner wall of the valve cover (4) has a first annular groove (41), the outer wall of the valve stem (1) and the A packing groove (5) is provided between the inner wall of the valve cover (4); the first annular groove (41) and the valve stem (1) surround the packing groove (5);

The sealing assembly (6), the sealing assembly (6) includes a pan-plug ring (61), the pan-plug ring (61) is sleeved outside the valve stem (1) and located in the packing groove (5) .
The valve stem sealing structure according to claim 1, wherein the sealing assembly (6) further comprises a packing arranged in the packing groove (5), and the packing is arranged on the pan-plug ring (61). ) One end away from the bottom of the first annular groove (41).
The valve stem sealing structure according to claim 2, characterized in that there is a gap between the packing and the pan-plug ring (61).
The valve stem sealing structure according to claim 2 or 3, wherein the packing is a V-shaped tetrafluoro packing (62).
The valve stem sealing structure according to any one of claims 1-4, further comprising a gland flange (7), and the gland flange (7) is sleeved on the valve stem (1). ) Outside and abutting on the valve cover (4); one end of the gland flange (7) facing the valve cover (4) is provided with a first groove, and the first groove is connected to the valve cover (4). A winding gasket (63) is provided between 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 bottom of the first groove. It is connected to the valve cover (4) to form a seal between the gland flange (7) and the valve cover (4).
The valve stem sealing structure according to claim 5, wherein a second groove is provided on the inner wall surface of the gland flange (7) facing the valve stem (1), and the second groove A first sealing ring (64) is provided inside; the inner side of the first sealing ring (64) is in contact with the valve stem (1), and the outer side of the first sealing ring (64) is in contact with the second concave The groove bottom of the groove abuts to form a seal between the valve stem (1) and the gland flange (7).
The valve stem sealing structure according to claim 5 or 6, wherein 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 the The second annular groove is provided with a graphite ring (65), the inner side of the graphite ring (65) abuts on the valve stem (1), and the outer side of the graphite ring (65) abuts on the pressure On the cover flange (7).
The valve stem sealing structure according to any one of claims 5-7, wherein an end of the gland flange (7) close to the valve cover (4) is provided with a protruding portion (71), The protruding portion (71) extends into the filler groove, and the filler abuts on the protruding portion (71).
The valve stem sealing structure according to any one of claims 5-8, further comprising a connecting flange arranged on the gland flange (7), and the connecting flange is sleeved on the gland flange (7). Outside the valve stem (1), a third groove is provided on the inner wall of the connecting flange, and a second sealing ring (66) is provided in the third groove. The inner side abuts on the valve stem (1), and the outer side of the second sealing ring (66) abuts on the bottom of the third groove.
A valve, characterized in that it comprises a valve body (9) and the valve stem sealing structure according to any one of claims 1-9.