CN117889261A - Valve rod sealing structure and valve - Google Patents

Abstract

The invention discloses a valve rod sealing structure and a valve, wherein the valve rod sealing structure comprises a valve body and a valve rod, and a mounting hole communicated with an inner cavity of the valve body is formed in the side wall of the valve body; the top of the valve body is provided with a gland flange, and a sealing hole which is communicated with the mounting hole in an aligned manner is formed in the gland flange in an axial penetrating manner; the sealing hole is a step hole, and one end of the sealing hole, which faces the mounting hole along the axial direction, is a large-diameter hole; the valve rod is rotatably arranged in the mounting hole and the sealing hole; the side wall of the part of the valve rod, which is positioned in the mounting hole, is convexly provided with a positioning part; the part of the valve rod, which is positioned in the large-diameter hole, is sleeved with a first filler, and the top end surface of the first filler is abutted against the inner top wall of the large-diameter hole; the valve rod is sleeved with an elastic piece, two ends of the elastic piece are respectively connected to two end faces of the positioning part and the first filler, and the elastic piece has an initial state of compressed storage force. The invention realizes the self-sealing of the valve rod under the double pressure effect and improves the sealing effect on the valve rod.

Description

Valve rod sealing structure and valve

Technical Field

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

Background

At present, the society is increasingly concerned about environmental protection, and many valve requirements meet the low leakage requirement, and the packing at the valve rod part of the valve is extremely easy to cause packing damage due to the opening and closing of the valve rod, so that leakage is generated, and the environment, equipment and even life are endangered.

The valve rod sealing structure of the existing valve generally adopts a structure that packing is pressed by means of an external pressing plate fastener, and comprises packing, a packing pad, a pressing plate, a pressing sleeve, a stud, a nut and the like, wherein the stud is arranged on the pressing plate in a penetrating manner, the nut is arranged above the pressing plate, and the packing pad are sleeved on the valve rod and are arranged on the lower side of the pressing sleeve. When the valve is installed, the nut is required to be screwed down, so that the nut and the stud apply downward pressure to the pressing plate and the pressing sleeve, the pressing plate and the pressing sleeve press the filler to generate pretightening force on the filler from top to bottom, and the filler is pressed against the outer wall of the valve rod and the inner wall of the stuffing box to achieve the sealing function. However, the valve rod sealing structure with the structure is sealed by means of the pretightening force applied by the nut and the pressing plate to the filler from top to bottom in the use process, the sealing effect is poor, and the valve rod sealing is easy to fail and leak.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the defects that the sealing effect of the valve rod sealing structure in the prior art is poor and the valve rod sealing is easy to fail and leak, so that the valve rod sealing structure and the valve are provided.

According to a first aspect of the present invention there is provided a valve stem seal comprising:

The side wall of the valve body is provided with a mounting hole communicated with the inner cavity of the valve body;

The gland flange is arranged at the top of the mounting hole of the valve body, a sealing hole is formed in the gland flange in an axial penetrating mode, and the sealing hole is communicated with the mounting hole in an aligned mode; the sealing hole is a step hole, and one end of the sealing hole, which faces the mounting hole along the axial direction, is a large-diameter hole;

A valve stem rotatably disposed within the mounting bore and the seal bore; the side wall of the part of the valve rod, which is positioned in the mounting hole, is convexly provided with a positioning part;

The first packing is sleeved on the valve rod, and the top end surface of the first packing is abutted against the inner top wall of the large-diameter hole;

The elastic piece is sleeved on the valve rod, two ends of the elastic piece are respectively connected with two end faces of the positioning part and the first filler, which face each other along the axial direction, and the elastic piece has an initial state of being compressed and accumulating force.

According to the valve rod sealing structure, at least the following technical effects are achieved:

The first packing is arranged in the large-diameter hole of the sealing hole, the top end surface of the first packing is abutted against the inner top wall of the large-diameter hole, and a compressed elastic component for accumulating force is arranged between the top end surface of the positioning part and the bottom end surface of the first packing, so that the elastic component always provides an initial sealing force for the first packing from bottom to top along the axial direction; on the other hand when the first packing appears wearing and tearing, the initial sealing force compression first packing that applys through the elastic component constantly warp and obtains automatic compensation to guarantee sealing reliability and the sealed effect to the valve rod, and then the effectual phenomenon emergence that prevents to be equipped with medium in this valve rod seal structure.

Preferably, a thrust washer is arranged between the elastic piece and the positioning part.

Preferably, a sleeve is arranged between the thrust washer and the elastic piece, and a first bearing is arranged between the inner side surface of the sleeve and the outer side wall of the valve rod.

Preferably, a circle of mounting groove is concavely formed in the mounting hole towards the sealing hole, a four-open ring is embedded in the mounting groove, and a part of the four-open ring extends out of the mounting groove; the sleeve is concavely provided with a circle of positioning groove towards the outer side face of one end of the thrust washer, and the positioning groove is matched with the four-opening ring.

Preferably, one end of the small-diameter hole of the sealing hole, which is away from the large-diameter hole, is communicated with an embedded hole, the aperture of the embedded hole is larger than that of the small-diameter hole, and a graphite sealing element is arranged in the embedded hole; the valve rod overcoat is equipped with top flange lid, top flange lid passes through first screw connection the top of gland flange, top flange lid along axial bottom face butt compress tightly in the top terminal surface of graphite sealing member.

Preferably, a second bearing is arranged between the inner side wall of the top flange cover and the outer side wall of the valve rod.

Preferably, a limiting groove is concavely arranged at the bottom end face of the top flange cover corresponding to the position of the embedded hole, a packing pressing ring is arranged in the limiting groove, the bottom end of the packing pressing ring extends out of the limiting groove, and the bottom end face of the packing pressing ring is abutted to and pressed on the top end face of the graphite sealing piece.

Preferably, a T-shaped packing backing ring is arranged between the elastic piece and the first packing, and the top end of the small-diameter part of the packing backing ring is abutted and pressed on the bottom end surface of the first packing; a circle of sliding grooves are concavely formed in the surrounding wall of one end, facing the mounting hole, of the large-diameter hole, and the large-diameter part of the packing backing ring is axially connected in the sliding grooves in a sliding manner;

and/or the elastic piece is arranged as a disc spring;

And/or the material of the first filler adopts PTFE.

Preferably, a leakage detection through hole is formed in the side wall of the gland flange, and the leakage detection through hole is communicated with a small-diameter hole of the mounting hole; and one end of the leakage detection through hole, which is away from the small-diameter hole, is detachably connected with a grease injector.

According to a second aspect of the present invention there is provided a valve comprising a valve stem seal as provided in the first aspect.

According to the valve, at least the following technical effects are achieved:

The valve rod sealing structure is characterized in that a first filler in a valve rod sealing structure is arranged in a large-diameter hole of a sealing hole, the top end surface of the first filler is abutted against the inner top wall of the large-diameter hole, a compressed elastic piece with a storage force is arranged between the top end surface of a positioning part and the bottom end surface of the first filler, the elastic piece always provides an initial sealing force for the first filler from bottom to top along the axial direction, on one hand, under normal working conditions, a medium flowing through the inner cavity of the valve body provides a medium pressure for the first filler from bottom to top along the axial direction through the positioning part, the first filler is enabled to deform along the radial direction of the first filler under the action of the initial sealing force exerted by the elastic piece and the medium pressure exerted by the medium, so that the axial force exerted by the first filler is converted into a radial sealing force pushing the inner side surface of the first filler to be in close contact with the outer side wall of the valve rod and pushing the outer side surface of the first filler to be in close contact with the large-diameter hole, and the self-sealing effect of the valve rod is achieved under the double pressure effect; on the other hand, when the first filler is worn, the initial sealing force applied by the elastic piece compresses the first filler to be continuously deformed so as to be automatically compensated, thereby ensuring the sealing reliability and the sealing effect of the valve rod and further effectively preventing the leakage of the medium in the valve.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of a valve stem seal incorporating the present embodiment;

FIG. 2 is an enlarged schematic view of FIG. 1 at A;

Fig. 3 is a schematic top view of a four-open ring of a valve stem seal structure according to this embodiment.

Reference numerals illustrate:

1-a valve body and 11-a mounting hole;

2-gland flanges, 21-sliding grooves, 22-leakage detection through holes, 23-second screws and 24-first sealing pieces;

3-valve rod, 31-positioning part;

4-a first filler;

5-an elastic member;

61-thrust washer, 62-sleeve, 621-first bearing, 63-four open ring, 64-packing grommet;

71-graphite seals;

8-top flange covers, 81-first screws, 82-second bearings and 83-packing compression rings;

9-fat injector.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

Example 1

As shown in fig. 1 and fig. 2, the valve rod sealing structure provided in this embodiment includes a valve body 1 and a valve rod 3, where a mounting hole 11 communicating with an inner cavity of the valve body 1 is provided on a side wall of the valve body 1; a gland flange 2 is arranged at the top of the mounting hole 11 of the valve body 1, a sealing hole is formed in the gland flange 2 in an axial penetrating mode, and the sealing hole is communicated with the mounting hole 11 in an aligned mode; the sealing hole is a step hole, and one end of the sealing hole, which faces the mounting hole 11 along the axial direction, is a large-diameter hole; the valve rod 3 is rotatably arranged in the mounting hole 11 and the sealing hole; the side wall of the part of the valve rod 3 positioned in the mounting hole 11 is convexly provided with a positioning part 31; a first filler 4 is sleeved on the part of the valve rod 3, which is positioned in the large-diameter hole, and the top end surface of the first filler 4 is abutted against the inner top wall of the large-diameter hole; the valve rod 3 is sleeved with an elastic piece 5, two ends of the elastic piece 5 are respectively connected with two end faces of the positioning part 31 and the first filler 4, which face each other along the axial direction, and the elastic piece 5 has an initial state of being compressed and accumulating force. It will be appreciated that the axial direction described in this embodiment refers to the axial direction of the valve stem 3, i.e. to the axial direction in fig. 1.

According to the valve rod sealing structure of the embodiment, the first packing 4 is arranged in the large-diameter hole of the sealing hole, the top end surface of the first packing 4 is abutted against the inner top wall of the large-diameter hole, the elastic piece 5 which is compressed and stores force is arranged between the top end surface of the positioning part 31 and the bottom end surface of the first packing 4, the elastic piece 5 always provides an initial sealing force for the first packing 4 along the axial direction from bottom to top, on one hand, under normal working conditions, a medium flowing through the inner cavity of the valve body 1 provides a medium pressure for the first packing 4 along the axial direction from bottom to top through the positioning part 31, so that the first packing 4 deforms along the radial direction of the first packing 4 under the action of the initial sealing force exerted by the elastic piece 5 and the medium pressure exerted by the medium, and the axial force exerted by the first packing 4 is converted into a radial sealing force which pushes the inner side surface of the first packing 4 to be in close contact with the outer side wall of the valve rod 3 and pushes the outer side surface of the first packing 4 to be in close contact with the wall of the large-diameter hole, and the self-sealing effect of the valve rod 3 under the double pressure effect is achieved; on the other hand, when the first packing 4 is worn, the initial sealing force applied by the elastic piece 5 compresses the first packing 4 to be continuously deformed to be automatically compensated, so that the sealing reliability and the sealing effect of the valve rod 3 are ensured, and the leakage of a medium in the valve provided with the valve rod sealing structure of the embodiment is effectively prevented.

As shown in fig. 1, in particular, the gland flange 2 is connected to the top of the mounting hole 11 of the valve body 1 by a second screw 23; so that the gland flange 2 and the valve body 1 are assembled and disassembled. As shown in fig. 2, more specifically, a first seal 24 is provided between the bottom end surface of the gland flange 2 and the top end surface of the valve body 1.

Specifically, the elastic member 5 is configured as a belleville spring, and the belleville spring can store larger energy when being compressed by a small deformation amount, so that the belleville spring is suitable for being used in a smaller axial space of a large-diameter hole of the valve rod sealing structure of the embodiment. As an alternative to the above-described solution, the elastic element 5 is provided as a helical spring.

Specifically, the material of the first filler 4 is PTFE. The PTFE has excellent corrosion resistance and can be compatible with most fluid media; and PTFE has the effect of self-lubrication, has a small friction coefficient, and effectively prevents the first filler 4 from wearing.

As shown in fig. 2, in some embodiments of the present invention, a thrust washer 61 is disposed between the elastic member 5 and the positioning portion 31. The contact area of the thrust washer 61 and the elastic piece 5 is further increased, so that the medium pressure generated by the medium flowing through the inner cavity of the valve body 1 is better and sequentially applied to the first packing 4 from bottom to top along the axial direction through the positioning part 31, the thrust washer 61 and the elastic piece 5, and the pressure self-sealing capability of the valve rod 3 under the normal working condition is further improved.

As a further optimization of the above embodiment, as shown in fig. 1 and 2, a sleeve 62 is disposed between the thrust washer 61 and the elastic member 5, a first bearing 621 is disposed on an inner side surface of the sleeve 62, and the valve rod 3 is connected in the first bearing 621. The rotation of the valve rod 3 is guided by the first bearing 621, and the sealing stability of the first packing 4 is improved.

As shown in fig. 1 to 3, as a further optimization of the above embodiment, a circle of mounting groove is concavely formed on the surrounding wall of one end of the mounting hole 11 facing the sealing hole, a four-open ring 63 is embedded in the mounting groove, and a part of the four-open ring 63 extends out of the mounting groove; the sleeve 62 is concavely provided with a circle of positioning groove on the outer side surface of one end facing the thrust washer 61, and the positioning groove is matched with the four-way ring 63. First, the four-opening ring 63 is provided with a position which is assembled in the mounting hole 11 and does not interfere with the valve rod 3 through the mounting groove, and then the sleeve 62 is ensured to be assembled more accurately through the positioning function of the four-opening ring 63, so that the sealing effect on the valve rod 3 is improved.

As shown in fig. 1 and 2, as a further optimization of the above embodiment, one end of the small diameter hole of the sealing hole, which is away from the large diameter hole, is communicated with an embedded hole, the aperture of the embedded hole is larger than that of the small diameter hole, and a graphite sealing element 71 is arranged in the embedded hole; the valve rod 3 is sleeved with a top flange cover 8, the top flange cover 8 is connected to the top end of the gland flange 2 through a first screw 81, and the top flange cover 8 is abutted and pressed on the top end surface of the graphite sealing piece 71 along the axial bottom end surface. In the case where PTFE is used as the material of the first filler 4, when the working environment is abnormally raised beyond the melting point of PTFE due to the occurrence of a sudden situation such as a fire, the first filler 4 is considered to be liable to cause a loss of the sealing function with respect to the valve stem 3; in the embodiment, a sealing line formed by a graphite sealing piece 71 is additionally arranged above the first filler 4 along the axial direction, so that the fireproof sealing is realized; the graphite seal 71 plays a role in preventing leakage after melting under the high temperature of the first filler 4, prevents leakage of the medium, and ensures the safety of use of the valve equipped with the valve stem seal structure of the present embodiment.

As a further refinement of the above embodiment, as shown in fig. 2, the inner side wall of the top flange cover 8 is provided with a second bearing 82, and the valve stem 3 is connected within the second bearing 82. The first bearing 621 and the second bearing 82 cooperate with each other to realize double guiding of the rotation of the valve rod 3, and further improve the sealing stability of the first packing 4.

As shown in fig. 1 and 2, as a further optimization of the above embodiment, a limit groove is concavely formed in the bottom end surface of the top flange cover 8 corresponding to the position of the embedded hole, a packing pressing ring 83 is disposed in the limit groove, the bottom end of the packing pressing ring 83 extends out of the limit groove, and the bottom end surface of the packing pressing ring 83 is pressed against the top end surface of the graphite seal 71. The position of the packing press ring 83 is limited by the limiting groove, so that a sufficient contact area is kept between the packing press ring 83 and the graphite sealing piece 71, and the pressure applied by the top flange cover 8 along the axial direction is uniformly transmitted to each position of the graphite sealing piece 71 through the packing press ring 83 when the first screw 81 is screwed down, so that the sealing effect on the valve rod 3 is further improved. Meanwhile, the sealing effect of the first packing 4 on the valve rod 3 is irrelevant to the pretightening force applied by the first screw 81 and the top flange cover 8, namely, the sealing effect of the first packing 4 on the valve rod 3 is not influenced even if the top flange cover 8 is removed.

As shown in fig. 1 and 2, in some embodiments of the present invention, a T-shaped packing spacer 64 is disposed between the elastic member 5 and the first packing 4, and a small diameter top end of the packing spacer 64 abuts against and is pressed against a bottom end surface of the first packing 4; a circle of sliding groove 21 is concavely arranged on the surrounding wall of the large diameter hole facing to one end of the mounting hole 11, and the large diameter part of the packing cushion ring 64 is axially and slidably connected in the sliding groove 21. Through the cooperation guiding action of the sliding groove 21 and the large-diameter part of the packing backing ring 64, the packing backing ring 64 moves along the axial straight line under the initial sealing force applied by the elastic piece 5 and the medium pressure applied by the medium, the applied axial force from bottom to top along the axial direction is uniformly transmitted to each position of the first packing 4 through the packing backing ring 64, the radial sealing force for pushing the inner side surface of the first packing 4 to be in close contact with the outer side wall of the valve rod 3 and pushing the outer side surface of the first packing 4 to be in close contact with the surrounding wall of the large-diameter hole is increased, and the sealing effect on the valve rod 3 is further improved.

As shown in fig. 1 and 2, in some embodiments of the present invention, a leakage detection through hole 22 is formed on a side wall of the gland flange 2, and the leakage detection through hole 22 is communicated with a small-diameter hole of the mounting hole 11; the leak hunting through hole 22 deviates from the one end of minor diameter hole can be dismantled and be connected with annotate fat ware 9. On the one hand, the sealing effect of the first filler 4 on the outer side wall of the valve rod 3 and the surrounding wall of the large-diameter hole can be checked through the leakage detection through hole 22; on the other hand also can be in leak hunting through-hole 22 can dismantle connection annotate fat ware 9, leak hunting through-hole 22 can regard as annotating fat hole to use this moment to annotate fat operation to the sealed hole in, further improve the sealed effect to valve rod 3. Specifically, the inner wall of one end of the leakage detection through hole 22, which is away from the small-diameter hole, is provided with an internal thread, the outer side wall of one end of the grease injector 9, which is towards the leakage detection through hole 22, is provided with an external thread, and the external thread is matched with the internal thread.

In the process of assembling the valve stem sealing structure of the present embodiment, the first packing 4 is loaded from the lower portion of the gland flange 2, and the first packing 4 is initially preloaded by the elastic member 5 to realize initial sealing; the elastic force of the elastic piece 5 finally acts on the four open rings 63, and the four open rings 63 play a role in bearing the pretightening axial force of the first filler 4 and the blowout prevention effect of the valve rod 3; because the first packing 4 is installed from the lower part of the gland flange 2, the sealing performance of the first packing 4 is irrelevant to the top flange cover 8 and the first screw 81, so the top flange cover 8 is a non-bearing member, namely, the sealing effect of the first packing 4 on the valve rod 3 is irrelevant to the pretightening force exerted by the first screw 81 and the top flange cover 8, namely, the sealing effect of the first packing 4 on the valve rod 3 is not affected even if the top flange cover 8 is removed.

Example two

Fig. 1 to 3 show a valve according to the present embodiment, including the valve stem sealing structure according to the first embodiment.

According to the valve of the embodiment, the first packing 4 in the valve rod sealing structure is arranged in the large-diameter hole of the sealing hole, the top end surface of the first packing 4 is abutted against the inner top wall of the large-diameter hole, the elastic piece 5 with compressed storage force is arranged between the top end surface of the positioning part 31 and the bottom end surface of the first packing 4, the elastic piece 5 always provides an initial sealing force for the first packing 4 along the axial direction from bottom to top, on one hand, under normal working conditions, a medium flowing through the inner cavity of the valve body 1 provides a medium pressure for the first packing 4 along the axial direction from bottom to top through the positioning part 31, so that the first packing 4 deforms along the radial direction of the first packing 4 under the action of the initial sealing force exerted by the elastic piece 5 and the medium pressure exerted by the medium, and the axial force from bottom to top borne by the first packing 4 is converted into a radial sealing force which pushes the inner side surface of the first packing 4 to contact with the outer side wall of the valve rod 3 and pushes the outer side surface of the first packing 4 to tightly contact with the large-diameter hole, and the sealing effect of the valve rod 3 is improved under the double pressure effect on the sealing effect of the valve rod 3; on the other hand, when the first packing 4 is worn, the initial sealing force applied by the elastic piece 5 compresses the first packing 4 to be continuously deformed to be automatically compensated, so that the sealing reliability and the sealing effect of the valve rod 3 are ensured, and the leakage of a medium in the valve is effectively prevented.

The valve in this embodiment may be a ball valve, a gate valve, a butterfly valve, or the like.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims (10)

1. A valve stem seal, comprising:

the valve comprises a valve body (1), wherein a mounting hole (11) communicated with the inner cavity of the valve body (1) is formed in the side wall of the valve body;

The gland flange (2) is arranged at the top of the mounting hole (11) of the valve body (1), a sealing hole is formed in the gland flange (2) in an axial penetrating mode, and the sealing hole is communicated with the mounting hole (11) in an aligned mode; the sealing hole is a step hole, and one end of the sealing hole, which faces the mounting hole (11) along the axial direction, is a large-diameter hole;

A valve stem (3) rotatably disposed within the mounting hole (11) and the seal hole; a positioning part (31) is convexly arranged on the side wall of the part of the valve rod (3) positioned in the mounting hole (11);

The first packing (4) is sleeved on the valve rod (3), and the top end surface of the first packing (4) is abutted to the inner top wall of the large-diameter hole;

the elastic piece (5) is sleeved on the valve rod (3), two ends of the elastic piece (5) are respectively connected with two end faces of the positioning part (31) and the first filler (4) which face each other along the axial direction, and the elastic piece (5) has an initial state of being compressed and accumulating force.

2. A valve stem sealing structure according to claim 1, wherein a thrust washer (61) is provided between the elastic member (5) and the positioning portion (31).

3. A valve stem sealing structure according to claim 2, characterized in that a sleeve (62) is arranged between the thrust washer (61) and the elastic member (5), and a first bearing (621) is arranged between the inner side surface of the sleeve (62) and the outer side wall of the valve stem (3).

4. A valve stem sealing structure according to claim 3, wherein a circle of mounting groove is concavely arranged on a surrounding wall of one end of the mounting hole (11) facing the sealing hole, a four-open ring (63) is embedded in the mounting groove, and a part of the four-open ring (63) extends out of the mounting groove; one end outer side surface of the sleeve (62) facing the thrust washer (61) is concavely provided with a circle of positioning groove, and the positioning groove is matched with the four-opening ring (63).

5. A valve stem sealing structure according to claim 3, wherein one end of the small diameter hole of the sealing hole, which is away from the large diameter hole, is communicated with an embedded hole, the aperture of the embedded hole is larger than that of the small diameter hole, and a graphite sealing element (71) is arranged in the embedded hole; the valve rod (3) overcoat is equipped with top flange lid (8), top flange lid (8) are in through first screw (81) connection gland flange (2)'s top, top flange lid (8) along axial bottom face butt compress tightly in the top face of graphite sealing member (71).

6. A valve stem sealing arrangement according to claim 5, characterized in that a second bearing (82) is arranged between the inner side wall of the top flange cover (8) and the outer side wall of the valve stem (3).

7. The valve rod sealing structure according to claim 5, wherein a limit groove is concavely formed in the bottom end face of the top flange cover (8) at a position corresponding to the embedded hole, a packing pressing ring (83) is arranged in the limit groove, the bottom end of the packing pressing ring (83) extends out of the limit groove, and the bottom end face of the packing pressing ring (83) is abutted and pressed on the top end face of the graphite sealing piece (71).

8. A valve stem sealing structure according to any one of claims 1 to 7, wherein a T-shaped packing grommet (64) is provided between the elastic member (5) and the first packing (4), and the small diameter portion top end of the packing grommet (64) is pressed against the bottom end face of the first packing (4); a circle of sliding grooves (21) are concavely formed in the surrounding wall of one end, facing the mounting hole (11), of the large-diameter hole, and the large-diameter part of the packing backing ring (64) is axially connected in the sliding grooves (21) in a sliding manner;

and/or the elastic element (5) is configured as a belleville spring;

And/or the material of the first filler (4) adopts PTFE.

9. A valve stem sealing structure according to any one of claims 1 to 7, wherein a leakage detection through hole (22) is formed in the side wall of the gland flange (2), and the leakage detection through hole (22) is communicated with the small diameter hole of the mounting hole (11); and one end of the leakage detection through hole (22) deviating from the small-diameter hole is detachably connected with a grease injector (9).

10. A valve comprising a valve stem seal according to any one of claims 1 to 9.