CN206530729U - A kind of valve rod leak-proof structure of ball valve under water - Google Patents

Abstract

A valve stem sealing structure of an underwater ball valve, including a valve stem and a valve stem mounting part, the valve stem is installed in cooperation with the mounting hole on the valve stem mounting part, and three sealing structures are provided between the valve stem and the mounting hole, wherein the first The second sealing structure adopts an elastic energy storage sealing ring group, the third sealing structure adopts two spring energy storage sealing ring groups, the second sealing structure and the third sealing structure are installed through a sealing cover, and one end of the sealing cover is pressed Tight elastic energy storage sealing ring group, the other end is provided with an outer flange, on the upper end surface of the outer flange there are two annular spaces for placing two spring energy storage sealing ring groups, and there is also a space for storing the two sets of spring energy The energy sealing ring is pressed against the gland on the elastic energy storage sealing ring group through the sealing cover. It can effectively ensure the sealing reliability of the valve stem of the underwater ball valve under the condition of the medium from low pressure to high pressure and withstand external pressure; effectively control the leakage of the medium, thereby ensuring the working safety of the underwater ball valve.

Description

A stem sealing structure of an underwater ball valve

technical field

The utility model relates to the technical field of underwater pipeline valves, in particular to a valve stem sealing structure of an underwater ball valve.

Background technique

For ball valves, between the valve stem and the mounting hole on the bonnet (top-entry ball valve) or the mounting hole on the valve body (side-entry ball valve) and between the flange and the gasket connecting the ball valve and the pipeline The consequences of external leakage are often more serious than the internal leakage between the valve seat and the ball. Therefore, the leakage of valves is an important symbol of civilized production and safe production, and it is also a measure of a country's industrial production management level and technological progress.

The valve stem of the ball valve only rotates, and a stuffing box is used to seal between the valve stem and the mounting hole. The structure is simple, the processing is convenient, and the price is low, so it is the most widely used. The stuffing box seal is mainly composed of stuffing box, stuffing, stuffing pad and stuffing pressing mechanism. The stuffing can choose graphite stuffing or PTFE stuffing according to different working conditions. This sealing form is widely used in petrochemical, shipbuilding, power station, metallurgy and other fields. However, the packing seal in the prior art has great limitations on the working conditions of the ball valve. Under the working conditions of external pressure and high internal pressure of the medium, it is difficult to guarantee the sealing form of ordinary packing seal and separate stuffing box. The reliability of the seal between the valve stem and the mounting hole.

How to realize the reliable sealing between the valve stem and the installation hole of the ball valve under the working conditions of external pressure and relatively high medium internal pressure has become an urgent problem to be solved.

Utility model content

In order to solve the above technical problems, the utility model provides a leak-proof underwater ball valve.

The technical solution adopted by the utility model in order to solve the above technical problems is: a valve stem sealing structure of an underwater ball valve, including a valve stem and a valve stem mounting part cooperating with the valve stem. Install the installation hole of the valve stem, and there are three sealing structures between the valve stem and the installation hole. The three sealing structures are the first sealing structure arranged at the junction of the stem mounting part towards the end of the valve cavity and the valve stem. , the second sealing structure located near the upper end of the valve stem mounting part and the third sealing structure located at the joint between the upper end of the valve stem mounting part and the valve stem, wherein the second sealing structure includes the middle part of the mounting hole The first sinking platform and the elastic energy-storage sealing ring group filled between the first sinking platform and the valve stem, the third sealing structure includes the second sinking platform located above the first sinking platform and close to the upper end of the installation hole and The sealing cover arranged between the second sinking platform and the valve stem and the two spring energy-storage sealing ring groups installed in cooperation with the sealing cover, one end of the sealing cover stretches into between the first sinking platform and the valve stem for sealing The elastic energy storage sealing ring group is pressed between the installation hole and the valve stem. The other end of the sealing cover is provided with an outer flange that is installed in cooperation with the table of the second sinking platform. The space between the sink platform and the valve stem is divided into two spacer rings of annular spaces, and the two spring energy storage sealing ring groups are respectively arranged in the two annular spaces, and the spring energy storage sealing ring group includes a U-shaped opening The top lip-shaped sealing ring, a U-shaped cross-section spring ring fitted with the U-shaped opening, the opening of the top lip-shaped sealing ring is set downward, and a U-shaped cross-section spring ring is arranged between the table top of the second sinking platform. There is an upper support ring, and an annular gasket with a rectangular cross-section is provided on the upper end of the top lip seal ring; there is also a ring for pressing two sets of spring energy storage seal rings on the elastic energy storage seal ring group through the seal cover. on the gland.

Further, the elastic energy storage sealing ring set includes a lower lip sealing ring, a middle lip sealing ring and an upper lip sealing ring, the lower lip sealing ring opens downward, and the cross section is " ” shape, in the opening of the lower lip seal ring, there is a V-shaped cross-section spring piece with the opening facing downward, and the V-shaped cross-section spring piece is supported on the table top of the first sinking platform through a lower support pad with a ring-shaped protrusion; The above-mentioned middle lip seal ring is V-shaped, and there are a plurality of them. The bottom middle lip seal ring is supported on the lower lip seal ring by a roughly triangular middle support ring with protrusions, and the other The middle lip seal rings are respectively supported on the adjacent middle lip seal rings through a "herringbone" support ring; the upper lip seal ring is Y-shaped with the opening facing downwards, which is passed through a "herringbone" shape The supporting ring is supported on the uppermost middle lip sealing ring, and a rectangular sealing ring is arranged on the upper end of the upper lip sealing ring.

Further, the inner peripheral wall of the rectangular sealing ring is provided with a plurality of annular sealing grooves.

Further, the first sealing structure includes an annular protrusion arranged on the valve stem and a thrust washer arranged between the annular protrusion and the end of the valve stem mounting part facing the valve cavity.

Further, the surface of the thrust washer is coated with a layer of PTFE.

Beneficial effect:

The utility model adopts three sealing structures for the valve stem seal (the seal between the valve stem and the installation hole is referred to as the valve stem seal), and the third sealing structure adopts two spring energy storage sealing ring groups respectively arranged on In the two annular spaces, the U-shaped cross-section spring ring 702 provides pre-tightening sealing force, which makes the top lip sealing ring 703 close to the side wall of the sealing groove, so that the medium with low pressure cannot pass through the contact seal of the sealing groove surface, thereby forming an effective seal from vacuum to low pressure. In addition, the internal pressure of the medium will assist the U-shaped cross-section spring ring 702 to store energy. The greater the pressure, the more fully the sealing lip of the top lip seal ring 703 will adhere to the contact sealing surface of the sealing groove, thereby forming a high-pressure seal.

In addition, because the U-shaped cross-section spring ring 702 permanently provides elastic force (that is, pre-tightening sealing force) to the top lip seal ring 703, it can compensate for the wear of the top lip seal ring 703 itself and the relative position between it and the mating parts. Eccentric, thus ensuring the permanent reliability of the third sealing structure.

In a word, the utility model can effectively ensure the sealing reliability of the underwater ball valve when the medium is from low pressure to high pressure and withstand external pressure; effectively control the leakage of the medium, thereby ensuring the working safety of the underwater ball valve.

The utility model is described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Figure 2 is an enlarged view of point I in Figure 1.

Fig. 3 is an enlarged exploded view of II in Fig. 2 .

Figure 4 is an enlarged view of III in Figure 2.

In the figure, 1. sphere, 2. valve stem mounting part, 201, first sinking platform, 202, second sinking platform, 3. valve stem, 4. gland, 5. first sealing structure, 501, ring-shaped Protrusion, 502, thrust washer, 6, second sealing structure, 601, lower support pad, 602, V-shaped section spring piece, 603, lower lip seal ring, 604, middle support ring, 605, middle lip Shaped seal ring, 606, "herringbone" shaped support ring, 607, upper lip seal ring, 608, rectangular seal ring, 7, the third sealing structure, 701, upper support ring, 702, U-shaped section spring ring, 703, Top lip seal ring, 704, annular gasket, 705, sealing cover, 705a, spacer ring, 8, sliding bearing.

detailed description

As shown in the figure, a valve stem sealing structure of an underwater ball valve includes a valve stem 3 and a valve stem mounting part 2 cooperating with the valve stem. A mounting hole for installing the valve stem is provided on the valve stem mounting part 2. There are three sealing structures between the valve stem 3 and the mounting hole.

The three sealing structures are the first sealing structure 5 arranged at the junction of the valve stem mounting part 2 towards the end of the valve cavity and the valve stem 3, the second sealing structure 6 disposed near the upper end of the valve stem mounting part 2 and The third sealing structure 7 is provided at the junction between the upper end of the valve stem mounting part 2 and the valve stem 3 .

The first sealing structure 5 includes an annular projection 501 provided on the valve stem and a thrust washer 502 provided between the annular projection 501 and the end of the valve stem mounting part 2 facing the valve cavity. The surface of the push washer 502 is coated with PTFE.

The second sealing structure 6 includes a first platform 201 located in the middle of the installation hole and an elastic energy-storage sealing ring set packed between the first platform 201 and the valve stem 3 .

In this embodiment, the elastic energy storage sealing ring set includes a lower lip sealing ring 603 , a middle lip sealing ring 605 and an upper lip sealing ring 607 .

The opening of the lower lip seal 603 is downward, and the cross-section is " In the opening of the lower lip seal ring 603, there is a V-shaped cross-section spring piece 602 with the opening facing downward. on the countertop.

The middle lip seal ring 605 is V-shaped, and there are several in number, and the lowermost middle lip seal ring 605 passes through a belt with a protrusion and is roughly triangular (that is, the cross section can be a rectangular bottom and a triangular shape. The shape formed by the combination of the top, the middle support ring 604 is supported on the lower lip seal ring 603, and the other middle lip seal rings 605 are respectively supported by a "herringbone" support ring 606 on the adjacent middle lip seal.

In this embodiment, there are three middle lip seal rings 605 .

The upper lip seal ring 607 is Y-shaped with the opening facing downwards. It is supported on the middle lip seal ring at the uppermost end by a "herringbone" support ring. sealing ring 608 . In order to further enhance the sealing effect, a plurality of annular sealing grooves are provided on the inner peripheral wall of the rectangular sealing ring 608 .

The third sealing structure 7 includes a second platform 202 located above the first platform 201 close to the upper end of the mounting hole, a sealing cover 705 arranged between the second platform and the valve stem 3 and cooperating with the sealing cover 705 The two spring energy sealing ring groups.

One end of the sealing cover 705 extends into the sealing letter formed between the first sinking platform 201 and the valve stem 3, and is used to compress the elastic energy storage sealing ring group between the installation hole and the valve stem 3. The sealing cover 705 The other end of the second sinking platform 202 is provided with an outer flange that is installed in cooperation with the table top of the second sinking platform 202. On the upper end surface of the outer flange, there is a partition that divides the space between the second sinking platform 202 and the valve stem 3 into two annular spaces. Ring 705a.

The two spring-energy sealing ring groups are arranged in two annular spaces respectively, and the spring-energy sealing ring group includes a top lip-shaped sealing ring 703 with a U-shaped opening, and a top lip-shaped sealing ring 703 fitted with the U-shaped opening. U-shaped cross-section spring ring 702, the opening of the top lip-shaped sealing ring 703 is set downwards, an upper support ring 701 is arranged between the U-shaped cross-section spring ring 702 and the table top of the second sinking platform 202, and the top lip-shaped sealing ring 703 An annular gasket 704 with a rectangular cross-section is provided at the upper end of the upper end; above the annular gasket 704, there is also an elastic energy storage for pressing two sets of spring energy sealing rings to the second sealing structure through the sealing cover 705 Gland 4 on the sealing ring group.

Concrete working principle of the present utility model is as follows:

When leakage occurs between the valve seat (not shown in the figure) and the ball 1, the medium reaches the cavity between the ball 1 and the valve stem mounting part 2, and the pressure of the medium increases. If the medium breaks through the first sealing structure 5, then Impurities such as solid particles in the medium are filtered out. Under the action of internal pressure, the lips of the lip seals of the elastic energy storage sealing ring group in the second sealing structure 6 change the contact state and increase the contact stress at the same time, so that the elastic energy storage sealing ring group cooperates with the valve stem 3 more tightly, making it difficult for the medium to pass through the second sealing structure 6.

Even if the medium passes through the lip of the lower lip seal 603, the internal pressure will lose a lot, and when it passes through the lip of the middle lip seal 605, the pressure will be lost again; the middle lip seal 605 is set to more At this time, every time the medium passes through a middle lip seal ring 605, the internal pressure will be lost. If this continues, when the upper lip seal ring 607 is reached, the internal pressure will be basically completely lost, so the leakage channel is stopped.

If the medium passes through the second sealing structure 6 and reaches the spring energy storage sealing ring group of the third sealing structure 7, due to the pressure compensation effect of the top lip sealing ring 703 (that is: between the U-shaped section spring ring 702 and the medium Under the action, the top lip seal ring 703 will be stretched, forming a tight fit with the sealing surface between the valve stem 3 to ensure the seal. The greater the pressure of the medium, the stronger the adhesion between the top lip seal ring 703 and the valve stem. Tight), can effectively prevent the leakage of the medium. Due to the pre-tightening force provided by the U-shaped section spring ring 702, the top lip seal ring 703 can also effectively prevent the external low-pressure medium from entering the pipeline system.

In the utility model, a three-sealing structure is adopted, especially the third sealing ring is sealed by a spring energy storage sealing ring group: two top lip-shaped sealing rings 703 are respectively installed between the isolation ring 705a and the valve stem mounting part 2 And in the sealing groove formed between the spacer ring 705a and the valve stem 3, the U-shaped section spring ring 702 provides a pre-tightening sealing force, so that the top lip-shaped sealing ring 703 is close to the side wall of the sealing groove, so that the pressure is low The medium cannot pass through the contact sealing surface of the sealing groove (that is, the opposite surface between the isolation ring 705a and the valve stem mounting part 2 and between the isolation ring 905a and the valve stem 5), thereby forming a vacuum to a low pressure range. Effective sealing, as shown in Figure 4. As the pressure of the medium rises, the pressure sealed in the sealing chamber (that is, the sealing space formed between the top lip seal ring 703 and the valve stem mounting part 2, the valve stem 3 and the table surface of the second platform) is also increasing. (Because the medium flowing inside the valve body has a high pressure, when the medium leaks to the outside through the gap between the valve stem 3 and the valve stem mounting part 2, it must first pass through the first sealing structure 5, and then pass through the second The first sealing structure 6, and finally reached the third sealing structure 7, the pressure mentioned here is getting higher and higher, it is assumed that the medium has passed through the first sealing structure 5 and the second sealing structure 6 to reach the sealing chamber), it can be Providing sufficient sealing force promotes the contact sealing surface of the sealing groove to form a reliable seal, thereby forming a high-pressure seal.

Since the U-shaped cross-section spring ring 702 permanently provides elastic force (that is, pre-tightening sealing force) to the top lip seal ring 703, it can compensate for the wear of the top lip seal ring 703 itself and its matching parts (valve stem installation 2 and The eccentricity of the relative position between the valve stems 3) ensures permanent reliability of the seal.

In this embodiment, the thrust washer 502 with PTFE coating is used as the first sealing structure for sealing, and a flat seal is formed between the valve stem 3, the thrust washer 502 and the valve stem mounting part 2. When the medium contains solid particles , can filter out impurities, effectively protect the sliding bearing 8 and the valve stem 3, and prevent solid particles from invading the next two seals.

The second sealing structure of this embodiment adopts an elastic energy storage sealing ring group with low fugitive leakage. As shown in Figure 3, each lip sealing ring (lower lip sealing ring 603, middle lip sealing ring 605, and upper lip seal ring 608), the outer diameter of its lip is larger than the inner diameter of the stuffing box (that is, the diameter of the valve stem installation hole above the first sinking platform 201), and the inner diameter of its lip is smaller than the outer diameter of the valve stem 3, such The structure makes each lip seal ring have a certain deformation after assembly, under the action of each support ring (lower support pad 601 and middle support ring 604), between the lip tip of each lip seal ring and the valve stem 3 A corresponding contact pressure is created for a reliable seal.

The up and down described in this article are consistent with the up and down of the accompanying drawing 1 itself. The stem mounting part 2 described in this article refers to the valve cover for the top-mounted ball valve; for the side-mounted ball valve, it refers to the split body. Top-entry ball valves and side-entry ball valves are prior art, and will not be described in detail herein.

Claims (5)

1. A valve stem sealing structure of an underwater ball valve, including a valve stem (3) and a valve stem mounting part (2) cooperating with the valve stem, and a valve stem mounting part (2) is provided with a valve stem The installation hole is characterized in that: there are three sealing structures between the valve stem (3) and the installation hole, and the three sealing structures are arranged on the end of the valve stem installation part (2) facing the valve cavity and the valve stem (3) ) at the junction of the first sealing structure (5), the second sealing structure (6) located near the upper end of the valve stem installation (2) and the upper end of the valve stem installation (2) and the valve stem (3) The third sealing structure (7) at the junction, wherein the second sealing structure (6) includes the first sinking platform set in the middle of the installation hole and filled in the first sinking platform (201) and the valve stem ( 3) The elastic energy storage sealing ring group between, the third sealing structure (7) includes the second sinking platform (202) set above the first sinking platform close to the upper end of the installation hole and the second sinking platform and the valve The sealing cover (705) between the rods and the two spring energy-storage sealing ring groups installed in cooperation with the sealing cover (705), one end of the sealing cover (705) protrudes between the first sinking platform and the valve stem (3) The space is used to press the elastic energy storage sealing ring group between the installation hole and the valve stem (3), and the other end of the sealing cover (705) is provided with an outer flange that is matched with the table surface of the second sinking platform (202) , on the upper end surface of the outer flange, there is an isolation ring (705a) that divides the space between the second platform and the valve stem into two annular spaces, and the two spring energy sealing ring groups are respectively arranged on two In the annular space, the spring energy sealing ring set includes a top lip sealing ring (703) with a U-shaped opening, a U-shaped section spring ring (702) fitted with the U-shaped opening, and the top lip sealing ring The opening of (703) is set downward, and an upper support ring (701) is provided between the U-shaped cross-section spring ring (702) and the table top of the second sinking platform (202), and the upper end of the top lip-shaped sealing ring (703) There is an annular sealing gasket (704) with a rectangular cross-section; there is also a gland (4) for pressing the two sets of spring energy storage sealing rings on the elastic energy storage sealing ring group through the sealing cover (705) . 2. The valve stem sealing structure of an underwater ball valve according to claim 1, characterized in that: the elastic energy storage sealing ring group includes a lower lip sealing ring (603), a middle lip sealing ring (605 ) and the upper lip seal (607), the lower lip seal (603) opens downward, and the section is " ” shape, a V-shaped cross-section spring piece (602) with the opening facing downward is provided in the opening of the lower lip-shaped sealing ring (603), and the V-shaped cross-section spring piece is supported by a lower support pad (601) with a ring-shaped protrusion. On the table of the first sunken platform (201); the said middle lip seal ring (605) is V-shaped, and there are several in number, and the lowermost middle lip seal ring passes through a roughly triangular The raised middle support ring (604) is supported on the lower lip seal ring (603), and the other middle lip seal rings (605) are respectively supported on the adjacent middle lip seal rings (606) by a "chevron" support ring (606). On the sealing ring; the upper lip sealing ring (607) is Y-shaped with the opening facing downwards, which is supported on the middle lip sealing ring at the uppermost end by a "herringbone" support ring, and the upper lip sealing ring ( 607) is provided with a rectangular sealing ring (608). 3. The stem sealing structure of an underwater ball valve according to claim 2, characterized in that: the inner peripheral wall of the rectangular sealing ring (608) is provided with a plurality of annular sealing grooves. 4. The valve stem sealing structure of an underwater ball valve according to claim 1, characterized in that: the first sealing structure (5) includes an annular protrusion (501) on the valve stem and A thrust washer (502) provided between the annular protrusion and the end of the valve stem mounting part (2) facing the cavity. 5. The stem sealing structure of an underwater ball valve according to claim 4, characterized in that: the surface of the thrust washer (502) is coated with a layer of PTFE.