JP6725931B2 - Lining type butterfly valve - Google Patents

Description

The present invention relates to a lining type butterfly valve, and more particularly to a seal structure on a valve blade side of a butterfly valve in which a valve body and a valve box are resin-lined.

The metal core of the valve body is resin-lined as a butterfly valve used in the flow of highly corrosive fluids in plants such as chemicals or in food-related flow paths, and a resin seat ring is attached to the inner peripheral surface of the valve box. There is known a butterfly valve having a so-called lining structure mounted with. In this case, a fluororesin having excellent chemical resistance and heat resistance is usually used as the lining material, but the fluororesin is poor in elasticity, and in particular, the valve is closed near the seal portion between the valve blade and the valve box side. Since the structure is such that the pressure sealing is performed at a timing, it is difficult to secure the sealing property, and leakage easily occurs. Therefore, in such a butterfly valve, a rubber backup ring is generally provided on the back side of the seat ring, and the elastic repulsive force of the backup ring is used to press the seat ring against the valve body to close the valve wings. It often compensates for the lack of elasticity. At that time, in order to secure the sealing property between the valve body and the seat ring over the entire peripheral surface, the seat ring is pressed against the upside and downside where the stem is mounted.

As a butterfly valve of this type, for example, in the prior art of the butterfly valve of Patent Document 1, a backup ring made of ring-shaped rubber or the like is attached to the outer peripheral surface of the seat ring, and the seat ring acts as a valve body by its elastic force. A pressed valve is disclosed.
In the butterfly valve of Patent Document 2, as in the butterfly valve described above, a ring-shaped backup ring is mounted on the outer peripheral surface side of the seat ring.
In these butterfly valves, the valve blade portion and the upside-down portion of the seat ring are pressed against the valve body by the ring-shaped integral backup ring.

On the other hand, in the butterfly valve of Patent Document 1, bushes for inserting the valve shaft are arranged around the upper and lower valve shaft holes, and a long backup ring is formed in an arc shape along the outer circumference of the seat ring between the upper and lower bushes. The seat ring is arranged so that the seat ring is pressed against the valve body by the bush, and the backup ring presses the valve vane portion against the valve body. At this time, the end surface of the backup ring is arranged so as to match the upper and lower bushes, and the gap between the upper and lower bushes and the backup ring is suppressed.

Unlike a general butterfly valve, these lining type butterfly valves are usually provided in a structure in which the valve box is divided into upper and lower parts in order to mount the lining portion in the valve box. When assembling the valve, first, on one of the divided top and bottom sides of the inner side of the valve box, one end surface of the backup ring is temporarily fixed to the bush outer peripheral surface with an adhesive or the like, and then, A seat ring, a valve body, and the like are placed on the valve box via the stem, and the lower half side of the seat ring is temporarily fixed to the valve box. Finally, while holding the backup ring by hand along the upper half of the seat ring, the remaining valve boxes on the top and bottom are placed from above, and the valve boxes are fixed by bolts to be integrated.

JP 2012-219819 A JP, 2003-166654, A

When the ring-shaped integral backup ring as in the prior art of Patent Document 1 or Patent Document 2 is used, this backup ring needs to be manufactured by molding, and a molding die for molding is also required. In this case, the backup ring cannot be shared when the inner diameter of the seat liner differs depending on the valve diameter or the stem diameter inserted into the top and bottom parts is different, so it is necessary to manufacture a backup ring each time, and its molding die is also required individually. .. As the number of backup rings increases, there is also the problem that storage and management will be difficult.
After assembling the valve, it is difficult to secure sufficient sealing performance of the top and bottom with the integrated backup ring, and even if a pressing spring is provided on the back side of the backup ring, the elastic force cannot be directly transmitted. Therefore, the sealing force may be insufficient and leakage may occur. Further, since the pressing force and the twist in the rotational direction are transmitted from the valve body, the top and bottom parts are worn out more and it becomes more difficult to secure the sealing property.

On the other hand, when the bush and the backup ring are used to secure the sealing performance as in Patent Document 1, the backup ring end face must be brought into contact with the upper and lower bushings in order to secure the sealing performance on the valve blade side. Therefore, when assembling the valve, the backup ring is temporarily fixed with one end surface attached to the upper or lower bush outer peripheral surface, and the other end surface (free end side) of the backup ring along the inner circumference of the body. When bent, it is necessary to provide the end surface with such a length that it comes into contact with the outer peripheral surface of the other bush. At that time, the backup ring is sandwiched between the body on the temporarily fixed side and the seat ring so that it is difficult to extend, and thus the backup ring is formed to be slightly longer than the outer peripheral surface of the seat ring.

As a result, after the valve is assembled, the backup ring will overhang to the seat ring side by the excess length, so that the seat ring tends to deform. Since it is not always supported by the valve body and there is no support in the centripetal direction except when the valve body is fully closed, the compressive deformation force of the backup ring concentrates in the central area and is easily deformed to the inner diameter side. Therefore, the seat ring is deformed into an elliptical shape with the top and bottom sides as long sides. Then, since the rigidity of the seat liner in the long side direction becomes high, a force is required to press the top and bottom sides in the disc direction to close the gap. This force can exceed the strength of the material.

At the time of fully closing the disc, a force is required to deform the seat liner along the circular disc outer periphery, which significantly increases the operating torque and causes excessive wear to the seat liner. It tends to occur and the thickness of the seat liner becomes thin.
As a result, if the backup ring is provided longer than the outer circumference of the seat ring, the sealing performance of the valve blade portion may be deteriorated.

At the time of assembly, it is necessary to attach this valve box to the valve box on the other side while suppressing the free end side of the backup ring to be stored from above into the groove formed in the valve box on the mounting side. If the backup ring is fixed in a state where it is inserted in the gap between the split positions of the valve box, the backup ring may be caught between the valve boxes and may be damaged or cut.

The present invention was developed in order to solve the conventional problems, the object is a lining type butterfly valve having corrosion resistance, while utilizing a versatile backup ring, the seat liner By preventing the deformation of the valve blade part, this valve blade part and the top and bottom part can secure a high sealing property over the entire circumferential surface, and it can be operated from the fully open to the fully closed state while exhibiting low torque characteristics Easy to assemble It is to provide a lining type butterfly valve having excellent performance.

In order to achieve the above object, the invention according to claim 1 is a butterfly valve in which a disc lined in a tubular body covered with a seat liner is provided openably and closably via a shaft attachment portion. The backup ring provided on the rear side of the seat liner is installed, and the sealing part of the disc consists of the top and bottom parts where the top and bottom parts of the disc contact and seal, and the valve wings other than the top and bottom part. In the central region of the valve blade portion other than the above portion, this divided portion is provided between the valve blade sides of the backup ring in the horizontal direction W1 or the tapered gap W2 before tightening the body during valve assembly. Is provided, and the valve wings of the backup ring are shorter than the gap W1 or the gap W2 after the completion of tightening to integrally fix the body composed of the upper body and the lower body divided in the central region of the valve blade portion of the disk. A lining type butterfly valve which is provided in a state of being separated from each other in a length or in a state where the valve wings of the backup ring are in contact with each other and reducing the deformation of the seat liner toward the inner diameter side in the central region of the valve wings.

According to the invention of claim 1, Ru can exhibit corrosion resistance and disuccinimidyl that body and the lining coated with sheet liner. Before the body is tightened, a split portion other than the top and bottom portions of the backup ring is provided with a horizontal gap W1 or a tapered gap W2 between the valve blade sides, and after the valve is assembled, the backup ring has the valve blade side. The length of the backup ring is set to be shorter than the length of the valve blade portion of the seat liner by separating them from each other by a length shorter than the gap W1 or the gap W2, or by providing the valve blade sides of the backup ring in contact with each other. Is also shortened to set the elastic force in the central region of the valve blade portion to be weaker than that in the adjacent region of the top and bottom portions, to reduce the deformation of the seat liner to the inner diameter side in the central region of the valve blade portion, The elastic force can be almost evenly transmitted to the valve blade portion of the seat liner to prevent a strong pressing force from being applied. Thus, maintaining the circular shape to prevent the sheet liner is deformed into an elliptical shape, along the entire circumference by the valve wing portion and top and bottom portions of the even preventing and Toraina the rigidity in the circumferential portion is higher It is possible to secure high sealing performance, and it is possible to operate while fully exhibiting low torque from full opening to valve closing. In this case, the gap W1 in the horizontal direction or the gap W2 having a tapered shape can be used. By using the existing general-purpose backup ring, it is easy to manufacture because the backup ring is not newly molded, and it is also easy to assemble. The backup ring can be mounted on the outer peripheral side of the seat liner without being formed longer than the outer peripheral side of the valve blade, and by adjusting the gap W, the deformation amount of the seat liner can be arbitrarily adjusted and the inner diameter side in the central region of the valve blade portion. Can be reduced.

It is a partially cutaway perspective view showing an embodiment of a lining type butterfly valve of the present invention. It is a center longitudinal cross-sectional view of the butterfly valve of FIG. It is a schematic longitudinal cross-sectional view of the butterfly valve of FIG. It is a schematic longitudinal cross-sectional view which shows other embodiment of the lining type butterfly valve of this invention. It is a partial notch schematic longitudinal cross-sectional view which shows the valve housing of another embodiment of the lining type butterfly valve of this invention.

Hereinafter, preferred embodiments of a sealing structure for a lining type butterfly valve according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows a partially cutaway perspective view of an embodiment of a lining type butterfly valve of the present invention, and FIG. 2 shows a central longitudinal sectional view of FIG.

In FIGS. 1 and 2, a butterfly valve (hereinafter referred to as a valve body 1) is used, for example, in a semiconductor manufacturing plant or a food-related pipeline, and has a cylindrical body 2, a seat liner 3, a disc 4, and a backup. It has a ring 5 and a stem 6, and this stem 6 has an upper stem 6a and a lower stem 6b.

The body 2 is formed of, for example, cast iron such as ductile cast iron, is provided in a vertically separable manner having an upper body 2a and a lower body 2b, and is integrally and detachably fixed by a bolt 10. The body 2 is provided with a channel opening 11 and a flange 12, which are covered with a sheet liner 3. A shaft mounting hole 13 is provided on the shaft mounting side of the stem 6 of the upper body 2a and the lower body 2b, and the upper stem 6a and the lower stem 6b are mounted in the shaft mounting hole 13, respectively. A shaft mounting portion 20 is provided on the disk mounting side of the shaft mounting hole 13, and the shaft mounting portion 20 has a ring body 21, a sealing bush 22, an O ring 23, and a bearing 24. Is the shaft seal area. Springs 25, which are coil springs, are mounted above and below the shaft attaching portion 20.

A backup ring insertion groove 30 is formed in a circular shape on the inner periphery of the upper and lower bodies 2a, 2b on the seal side with the disc 4, and the backup ring 5 is provided in the insertion groove 30 so as to be attachable. The insertion groove 30 is provided in such a manner that the end face of the backup ring 5 is provided in each shaft seal portion 20 in the vertical direction with a circumferential length that does not hinder the adhesion. In the present embodiment, the insertion groove 30 is formed to communicate with the insertion hole of the sealing bush 22 of the body 2. doing.

The seat liner 3 is provided with a resin material such as a fluororesin such as PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer) to a thickness of about 3 mm and is coated on the inner peripheral side of the body 2. This makes it possible to exhibit high corrosion resistance and heat resistance. The seat liner 3 has an annular portion 3a mounted on the inner peripheral side of the body 2 and flange portions 3b projectingly formed on the outer peripheral edges of both ends of the annular portion 3a, and the upper and lower stems 6a of the annular portion 3a, Cylindrical lining portions 3c and 3c are integrally formed at the mounting position of 6b, and upper and lower stems 6a and 6b are provided so that they can be inserted into these tubular lining portions 3c, respectively.

The disc 4 has a core metal 31 and a lining portion 32. The cored bar 31 is made of, for example, a stainless alloy and formed into a disk shape. The surface of the cored bar 31 which is the liquid contact surface is coated with a resin material such as PFA or the like with a fluororesin in a thickness of 3 mm, for example. As a result, the lining portion 32 is provided.

The lining portion 32 has a boss surface 35 on the top and bottom sides of the disc 12, and a shaft tube lining portion 36 extending from the boss surface 35 and covering the outer periphery of the stem 13, and is formed at an appropriate position on the cored bar 31. The outer periphery of the cored bar 31 is integrally covered through the through hole 31 a formed so as to prevent the cored bar 31 from being detached.

In this way, since the top and bottom of the disc 4 is provided on the top and bottom side of the disc 4, the seal portion of the disc 4 is the top and bottom part 40 with which the top and bottom part 35 makes contact and seals, and the top and bottom parts other than this top and bottom part 40. It consists of a valve vane portion 41. The top-bottom portion 40 of the sealing portion exerts the top-bottom side sealing property between the disc 4 and the seat liner 3 from the valve opening to the valve closing state, and the valve blade portion 41 of the sealing portion exerts the disc 4 in the valve closed state and the seat liner 3 And the valve blade side sealing property is exhibited, and in the valve closed state, the sealing property between the disc 4 and the disk 4 is exerted over the entire inner peripheral surface of the seat liner 3 due to the sealing portion by the top and bottom portions and the valve blade portion. ..

A stem insertion hole 33 is formed on the top and bottom sides of the disk 4, and a square hole portion 34 is formed in the stem insertion hole 33 on the top side. The upper stem 6a is inserted into the square hole portion 34, and the lower stem 6b is inserted into and fitted into the stem insertion hole 33. As a result, the disc 4 is axially mounted by the upper stem 6a and the lower stem 6b via the upper and lower shaft attachment portions 20 of the body 2, and is provided in the body 2 so as to be openable and closable by the rotation of the upper stem 6a side. There is.

1 to 3, the backup ring 5 is provided with a predetermined width and length by a rubber material having elasticity such as FKM (fluorine rubber) and EPDM (ethylene propylene rubber), for example, and has general versatility. It has a substantially square cross section and a short length. The backup ring 5 is inserted into the insertion groove 30 and is arranged on the back side of the annular portion 3a of the seat liner 3. As a result, the backup ring 5 presses the annular portion 3a of the seat liner 3 toward the inner diameter side, and when the valve is closed, the valve blade portion 41 at the sealing portion is firmly sealed.

When the backup ring 5 is provided with an appropriate thickness having a substantially square cross section, an appropriate crushing allowance is secured for a constant crushing rate. In this case, if the thickness is thin, the fluctuation range of the crushing rate becomes large due to the variation in dimensions, and the operating torque at the time of valve closing may suddenly increase or the sealing may worsen. On the other hand, if the thickness is too thick, the insertion groove 30 must be set to a deep dimension under the condition that the maximum outer diameter and the minimum outer diameter of the body 2 are limited by the dimensions of the pipe, and the compressive strength of the body 2 is increased. There is a possibility that the minimum wall thickness for satisfying the above condition cannot be secured. Further, if it is too thick, the effect of thermal expansion becomes large, and the operating torque when the valve is closed may suddenly increase.
The backup ring 5 in this embodiment has its thickness (radial length in FIG. 1) and width (axial length of the valve in FIG. 1) before being mounted in the backup ring insertion groove 30 of the body 2. In this state, each section has a square cross section set to 10 mm.

The backup ring 5 is divided by the valve vane portion 41, so that the elastic force in the central region α of the valve vane portion 41 is applied to the adjacent region β adjacent to the top-bottom portion 40, that is, the portion in contact with the boss surface 35 of the disc 4. It is set weaker in comparison, and the deformation of the seat liner 3 in the central region α of the valve blade portion 41 toward the inner diameter side is reduced.

More specifically, the left and right backup rings 5 are divided into two equal parts at a position farthest from the upside-down portion 40 of the valve blade portion 41, that is, at a central region α of the valve blade portion 41, and sandwiched between the upside-down portions 40. Two on each side, four in total, are arranged in the circumferential direction. The divided backup rings 5 have the same shape.

By arranging the backup ring 5 as described above, in the central region α of the valve blade portion 41 of FIG. 3, the elastic force is set to be weak in a region of, for example, about ±30° from the horizontal direction. It is desirable to weakly reduce the elastic force at the horizontal position, that is, at the position where the distance from the top-bottom portion 40 is the longest in the central region α.
In the present embodiment, the elastic force in the central region α of the valve blade portion 41, specifically, the compression rate of the backup ring 5 is 70% to 90%, more preferably, compared to the adjacent region β of the upside-down portion 40. Is set to 70% to 80%.

In the state before mounting the body 2 in FIG. 3, the valves 5 of the upper and lower backup rings 5 are in a state where the top and bottom end surfaces 5a of the respective backup rings 5 are in contact with the outer circumference of the ring body 21 and the sealing bush 22 of the shaft seal portion 20. Gaps W1 are provided at appropriate intervals between the blade-side end surfaces 5b.

On the other hand, on the shaft seal portion 20 side, a cylindrical bearing 24 is provided on the outer peripheral side of the stem 6 mounted in the shaft mounting hole 13, and a metal is provided between the bearing 24 and the seat liner 3 located below. The cylindrical ring body 21 made of is provided so as to be sandwiched between them.

The ring body 21 is made of a stainless material with a diameter capable of strongly pressing the position near the outer periphery of the boss surface 35 of the disk 4 from the upper side. The elastic force of the spring 25 is provided so as to be transmitted.

In FIG. 2, a bearing member 50 is arranged in the shaft mounting hole 13 of the upper body 2a in a state of being locked by a holding ring 51, and the spring 25 is supported by the bearing member 51 so as to be elastically downward. To be done. On the other hand, the top member 52 is arranged in the shaft mounting hole 13 of the lower body 2b in a state of being locked by the holding ring 51, the bearing member 53 is superposed on the top member 52, and the bearing member 53 is interposed therebetween. The spring 25 is supported so that it can be elastically splayed upward. The upper and lower springs 44, 44 are respectively repelled in the disc 4 direction by the bearing members 50, 53 and the top member 52. On the inner and outer circumferences of the bearing member 50 and the top member 52, dust-proof and waterproof O-rings 54, 54 are mounted, respectively.

The bearing 24 is disposed between the spring 25 mounted in the shaft mounting hole 13 and the ring body 21, and the bearing 24 allows the upper stem 6a and the lower stem 6b to rotate in the vicinity of the O-ring 23 and be aligned. Supported by. The bearing 24 is provided in a two-layer structure in which a resin bushing 24b with a back metal is mounted on the inner circumference of a bearing bush 24a made of metal such as stainless steel.

The bearing bush 24a is provided on the outer diameter to which the spring 25 abuts and the elastic force is applied. When the elastic force is applied, the end surface side abuts the ring body 21, and the ring body 21 can be pressed to the disc 4 side. It is provided in. In this case, the end surface of the bearing bush 24a on the disc 4 side may be in contact with the end surface of the sealing bush 22, but it is not necessary to apply a pressing force to the sealing bush 22 from the bearing bush 24a.

The sealing bush 22 is made of a brim-shaped member, is molded from a resin material such as PTFE (polytetrafluoroethylene) containing carbon fiber, and seals between the ring body 21 of the shaft mounting hole 13, the lining portion 32 and the seat liner 3. Is provided as. A cylindrical portion 22a is formed on the sealing bush 22, and an annular flange portion 22b is formed on the lower side of the cylindrical portion 22a so as to be bent in the outer peripheral direction. The end surface 21a of the ring body 21 abuts on the collar portion 22b, and thus the ring body 21 presses the seat liner 3 via the collar portion 22b. The sealing bush 22 is mounted so that the cylindrical portion 22a is interposed between the cylindrical lining portion 3c and the ring body 21, and the ring body 22 prevents the diameter expansion of the cylindrical lining portion 3c via the cylindrical portion 22a. To be done.

With such a configuration, in the valve body 1 shown in FIG. 2, the spring 25 provided in the shaft mounting hole 13 of the body 1 is positioned on the boss surface 35 of the disk 4 via the ring body 21 by the elastic force. By pressing the seat liner 3, the sealing performance of the top and bottom portion 40 is maintained.

At the same time, by sandwiching the sealing bush 22, the tubular lining portion 3c, and the shaft tubular lining portion 36 between the ring body 21 and the stem 6, it is possible to prevent the shaft seal portion 20 from expanding in diameter and at the sliding contact portion. It is designed to exert the sealing property of a certain shaft sealing portion 20.

Although the backup ring 5 in the above-described embodiment is divided into the left and right sides on the upside-down portion 40 side, it may be integrally provided on the upside-down portion 40 side. In this case, the backup ring has a substantially semicircular shape. ..

The cross-sectional shape of the backup ring 5 is not limited to a substantially square shape, and may be provided in an appropriate cross-sectional shape such as a substantially rectangular cross-section in accordance with the shape of the insertion groove 30 and the like. Further, if the deformation of the seat liner 3 toward the inner diameter side in the central region α of the valve blade portion 41 can be reduced, the backup ring 5 is not necessarily divided and the cross-sectional shape of the valve blade portion 41 is changed. Good.

The end surface 5a of the backup ring 5 is preferably a concave curved surface that follows the outer peripheral surfaces of the ring body 21 and the sealing bush 22, and in this case, the end surface 5a can be placed in a positioned state by being in close contact with the shaft seal portion 20. Even in the vicinity of the boundary with the shaft seal portion 20, the elastic force of the backup ring 5 can be caused to function in the seat liner 3, and the sealing performance of the entire valve blade portion 41 can be improved. On the other hand, the end surface 5a may be provided in a flat shape, and in this case, the existing backup ring can be provided without processing the end surface.

Further, although the coil spring is used as the spring 25, the present invention is not limited to this, and for example, a disc spring may be used.

Next, a procedure for assembling the valve body 1 described above will be described. When assembling the valve body 1, its upper and lower sides are similarly assembled.
In FIG. 2, first, the disc 4 in which the core metal 31 is covered with the lining portion 32 is incorporated into the inner peripheral side of the seat liner 3. At this time, the upper and lower axial cylinder lining portions 36 of the disc 4 are respectively inserted into the cylindrical lining portions 3c of the seat liner 3. In this state, the sealing bush 22 to which the O-ring 23 is attached is attached to the outer periphery of the tubular lining portion 3c. At this time, the collar portion 22b is fitted on the outer peripheral side of the tubular lining portion 3c, and the O-ring 23 is brought into contact with the outer periphery of the shaft tubular lining portion 36. Further, the ring body 21 is mounted on the outer periphery of the sealing bush 22 while the bottom surface is in contact with the upper surface of the collar portion 22b. As a result, the metal ring body 21 holds the sealing bush 22 from the outer peripheral side.
In this state, the upper stem 6a and the lower stem 6b are inserted inside the barrel lining portion 36 and connected to the stem insertion hole 33.

On the other hand, the bearing 24, the spring 25, the bearing members 50 and 53, and the top member 52 are mounted in the shaft mounting holes 13 of the upper body 2a and the lower body 2b, respectively, and the bearing member 50 and the top member 52 are respectively attached to the holding ring 51. Prevents slipping out by locking.

Subsequently, the four backup rings 5 are mounted so as to fit into the insertion grooves 30 of the upper and lower bodies 2a and 2b. At this time, the top-bottom side end surface 5a of each backup ring 5 is brought into contact with the outer circumference of the ring body 21 and the sealing bush 22 which are the shaft seal portions, and brought into close contact with each other. In order to maintain this close contact state, the outer peripheral surface near the end surface 5a of the backup ring 5 may be temporarily fixed to the inner circumference of the body 2 with an adhesive or the like.

Next, as shown in FIG. 1 and FIG. 2, the seat liner 3 having the disc 4, the sealing bush 22, and the ring body 21 is attached to the upper body 2a and the lower body 2b having the backup ring 5 on the inner peripheral side. Make sure you sandwich it. At this time, since the top-bottom side end surface 5a of each backup ring 5 is brought into contact with the outer circumferences of the ring body 21 and the sealing bush 22 as described above, a gap is formed between the valve blade side end surfaces 5b of the upper and lower backup rings 5, respectively. W1 is provided.

Finally, the upper body 12a and the lower body 12b are tightened with the bolts 10 and fixed integrally, whereby the assembly of the valve body 1 is completed. At this time, in a state where the top-bottom side end surface 5a of the backup ring 5 is in contact with the outer periphery of the shaft seal portion 20, the valve blade side end surfaces 5b are slightly separated from each other by a length shorter than the gap W1, or slightly. They are integrated in contact with each other.

Next, the operation of the above-described embodiment of the lining type butterfly valve of the present invention will be described.
As shown in FIGS. 1 and 2, the valve body 1 is provided with a divided backup ring 5 on the back side of the seat liner 3, and the backup ring 5 is provided in a short shape having a substantially square cross section. Since the backup ring 5 is not provided in the ring shape as described above, it is not necessary to newly form the backup ring 5 according to the valve diameter, the stem diameter, etc., and the existing backup ring having general versatility is processed. Can be shared. For this reason, the number of types of the backup ring 5 is reduced, and storage and management are facilitated.

Compared with the case of using the ring-shaped integrated backup ring, the sealing portion is the top and bottom portion 40 and the valve blade portion 41, and in the top and bottom portion 40, the shaft sealing portion 20 is directly attached to the seat liner 3 by the elastic force of the spring 25. Since it can be pressed, it exhibits high sealing performance and reliably prevents leakage from the top and bottom sides. Since the backup ring 5 is not positioned on the upside-down portion 40 as described above, it is possible to suppress the wear of the backup ring 5 due to the rotation of the stem 6 and maintain the sealing performance of the upside-down portion 40.

The backup ring 5 divided by the central region α of the valve blade portion 41 is arranged on the rear surface side of the seat liner 3, and the valve face portion 5b of the valve blade portion 41 is slightly separated or slightly contacted with the valve. By integrating the main body 1, the end surface 5a of the backup ring 5 is closely adhered to the shaft seal portion 20 such as the ring body 21 and the sealing bush 22 on both the top side and the ground side, and the length of the backup ring 5 is increased. The length can be made shorter than the length of the valve blade portion 41 of the seat liner 3. As a result, the elastic force in the central region α of the valve blade portion 41 where the backup ring 5 is separated or in slight contact is set to be weaker than that in the adjacent region β of the upside-down portion 40, and the central portion of the valve blade portion 41 is set. The deformation of the seat liner 3 in the area α toward the inner diameter side is reduced.

With the above configuration, the elastic force of the backup ring 5 is applied to the valve blade portion 41 of the seat liner 3 substantially evenly, and no local pressing force is applied to the seat liner 3. It is possible to prevent a strong pressing force from being applied near the area α. Therefore, it is possible to prevent the seat liner 3 from being deformed in an elliptical shape and to prevent the rigidity of the top and bottom portion 40 from increasing.

When the valve body 1 in FIG. 2 is fully closed, the top and bottom sides of the seat liner 3 and the valve wing side are pressed and sealed to the disc 4 via the elastic force of the spring 25 and the elastic force of the backup ring 5, respectively. A high sealing property is secured at the sealing portion on the entire peripheral surface from the top and bottom portion 40 to the valve blade portion 41, and the local deformation of the seat liner 3 on the valve blade side is suppressed. Therefore, the operability can be improved by suppressing a remarkable increase in the operation torque at the time of the fully closing operation, and an excessive force to the seat liner 3 and the lining portion 32 can be prevented to suppress wear and deformation, thereby extending the life. it can.

At this time, since the valve blade side of the seat liner 3 can be uniformly deformed into a substantially circular shape along the outer peripheral surface of the disc 4, the state before the seat liner 3 is reduced in diameter by the elastic force of the backup ring 5 is not shown. If the inner diameter of the seat liner 3 is set to be substantially the same as the outer diameter of the disc, the seat liner 3 tries to restore the original inner diameter as the disc 4 rotates when the valve is closed. The sealability can be exhibited without requiring a force to crush the liner 3 in the disc 4 direction. As described above, since the seat liner 3 does not exert a force to reduce the diameter of the disc 4 when the valve is closed, the operation torque can be reduced, and as described above, the valve blade side of the seat liner 3 is substantially even. By applying such a force, it is possible to effectively exhibit this low torque property and further improve the sealing property when the valve is closed.
In this case, as described above, the length of the insertion groove 30 of the upper and lower bodies 2a and 2b is made substantially the same as the length of the two backup rings 5 combined in the upper and lower directions, whereby the valve blade portion 41 of the backup ring 5 is Since the elastic force can be surely weakened as compared with the top and bottom portion 40, the above characteristics can be exhibited.

When assembling the valve body 1, the top and bottom end surfaces 5a of the backup ring 5 are temporarily fixed to the upper and lower bodies 2a and 2b in advance, so that the upper body 2a and the lower body 2b can be combined without pressing the backup ring 5 by hand. , Workability is improved.
Moreover, since the valve blade side end surface 5b of the divided backup ring 5 is located at a position that coincides with or does not reach the divided surfaces of the upper and lower body bodies 2a and 2b, the backup ring 5 is moved to the upper and lower body bodies 2a and 2b during assembly. It will not get caught or cut between the two.

FIG. 4 shows another embodiment of the lining type butterfly valve of the present invention. Note that, from this embodiment onward, the same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

In this embodiment, the divided end portions 61 of the backup ring 60 provided above and below the seat liner 3 are provided in a tapered shape, and the divided end portions 61 are arranged so as to overlap each other on the outer periphery of the seat liner 3. In this case, the angle θ from the horizontal direction of the divided end portions 61 is set to, for example, 30° to 60°, and the upper and lower backup rings 60 before being integrated as a butterfly valve are appropriately arranged between the divided end portions 61. It is attached with a gap W2.

In this case, as in the case of FIG. 2, when the seat liner 3 is sandwiched between the upper and lower bodies 2a and 2b and integrated, the split end portion 61 of the backup ring 60 in FIG. 4 is provided in a tapered shape. When these move in the horizontal direction and overlap with each other, a gap (not shown) is provided on the inner diameter side, and the backup ring 60 is inserted into this gap, so that the valve blade portion 41 of the backup ring 60 is inserted in the same manner as in the case of FIG. The elastic force in the central region α can be reliably set weaker than that in the adjacent region β of the upside-down portion 40.

Moreover, the amount of deformation of the seat liner 3 can be adjusted by adjusting the angle θ and the size of the interval W2. At this time, the range in which the deformation amount of the backup ring 60 can be adjusted can be set by changing the angle θ, and the larger the angle θ, the wider the range in which the deformation amount can be adjusted.
On the other hand, the amount of deformation of the seat liner 3 can be changed by adjusting the distance W2. For example, when the distance W2 is 0, the amount of deformation is the same as when the upper and lower backup rings 60 are connected, and the distance W2 is increased. When is increased, the deformation amount of the seat liner 3 can be reduced.
As described above, by adjusting the angle θ and the interval W2, it is possible to intentionally change the deformation amount of the seat liner 3 near the top and bottom and near the valve blades.

Further, although not shown, the taper shape of the split end portion 61 of the backup ring 60 may be reversed. In this case, when the seat liner 3 is turned upside down, the same direction as the taper shape of the backup ring 60 in FIG. 4 is obtained. Therefore, when the butterfly valve is assembled, the taper backup ring in the reverse direction is attached. When the upper body is turned upside down and the lower body is placed on the upper body from above, the backup ring of the lower body can be installed while being guided by the backup ring that opens in the direction in which the upper body expands. As a result, the upper body backup ring is prevented from expanding with respect to the lower body backup ring, and the split end portions are prevented from being caught, and the upper and lower body bodies can be smoothly combined to improve the assemblability.

In addition to the above, for example, the backup ring is thinly formed in the central region of the valve vane portion, that is, the radial thickness in FIG. 1 is shortened, so that the inner diameter side of the seat liner in the central region of the valve vane portion is formed. Can also be reduced. In this case, the dimensions and forming range of the thin portion can be set appropriately.When forming the thin portion in this way, in addition to dividing the backup ring in the central region of the valve blade, the left and right backup rings sandwiched between the top and bottom It is also possible to integrate each.

FIG. 5 shows still another embodiment of the lining type butterfly valve according to the present invention.
In this embodiment, a backup ring insertion groove 71 formed on the inner periphery of the body 70 is provided with a diameter-increasing groove 72 whose diameter is increased in the central region of the valve blade portion, and the seat liner 3 described above in the central region of the valve blade portion is provided. The deformation to the inner diameter side is reduced. In this case, the enlarged diameter groove 72 is provided symmetrically in the shape of, for example, a substantially circular arc, which facilitates processing. When the enlarged diameter groove portion is provided in an arc shape, the range for adjusting the deformation amount of the backup ring 5 can be appropriately set by adjusting the radius and the center position. On the other hand, the amount of deformation of the seat liner 3 can be appropriately set by adjusting the depth of the enlarged diameter groove 72 and the center of the radius.

1 Valve body 2 Body 3 Seat liner 4 Disk 5, 60 Backup ring 20 Shaft seal part (shaft contact part)
30, 71 Insertion groove 35 Boss surface (top and bottom)
40 Top-and-bottom part 41 Valve wing part 61 Divided end part α Central area β Adjacent area

Claims (1)

In a butterfly valve in which a disc lined in a tubular body covered with a seat liner is openably and closably mounted via a shaft attachment part, a backup ring provided on the inner peripheral surface of the body is arranged on the back side of the seat liner. The disc seal portion is composed of a top and bottom portion where the top and bottom portions of the disc contact with each other and a valve blade portion other than the top and bottom portions, and the backup ring is a central region of the valve blade portion other than the top and bottom portion of the disc. in divided, the separation portion, before fastening of the body during assembly of the valve, the gap W1 or tapered gap W2 in the horizontal direction between the valve blade-side ends of the backup ring is provided, valve wing of disuccinimidyl After the completion of tightening to integrally fix the body composed of the upper body and the lower body divided in the central region of the portion, the valve blade sides of the backup ring are separated from each other by a length shorter than the gap W1 or the gap W2. Alternatively, the lining type butterfly valve is characterized in that the valve wings of the backup ring are provided in contact with each other to reduce the deformation of the seat liner toward the inner diameter in the central region of the valve wings.

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