JP6738741B2 - Lining type butterfly valve - Google Patents

Description

The present invention relates to a lining type butterfly valve in which a valve body and a valve box inner peripheral surface are provided with a resin lining, and more particularly, to a butterfly valve having improved sealability on the vertical side of the valve body and in the vicinity of a shaft seal portion of a valve rod.

Conventionally, when using a highly corrosive fluid to be used in a plant for the chemical industry, as a butterfly valve used in food-related flow paths, etc., the metal core of the valve body is covered with a resin lining layer, There is known a butterfly valve having a so-called lining structure in which a resin seat ring is attached to the inner peripheral surface of a valve box. In this lining type butterfly valve, the valve body lining layer and the resin seat ring are made of a resin material such as PTFE or PFA. Since no other material touches the fluid, there is a severe corrosive fluid such as chlorine gas or hydrochloric acid. Suitable for chemical fluids, chemicals, foods, solvents, etc.

In this type of lining butterfly valve, in order to prevent external leakage of fluid from the top and bottom sides of the valve body and the vicinity of the shaft seal portion of the valve rod, a plurality of seal structures are provided in stages in the vicinity thereof. The top-bottom side seal structure is called a top-bottom seal and is provided as a primary seal. In the upside-down seal, the resin seat ring mounted on the inner circumference of the valve box is sealed by pressing on the upside and downside of the valve body, that is, the peripheral surfaces of the valve rod insertion holes on the upper side and the lower side, respectively. Fluid leakage is prevented, and fluid leakage around the valve rod connected to the valve body is prevented at the position closest to the valve body.
The seal structure of the shaft seal portion of the valve rod is a so-called shaft seal, and is provided as a secondary seal concentrically with the valve rod at a position axially outward of the valve rod relative to the primary seal of the butterfly valve. The shaft seal prevents fluid leakage around the valve rod and also prevents fluid leakage (so-called back leakage) between the valve box and the resin seat ring.
Further, a seal member such as an O-ring may be disposed as a tertiary seal at a position axially outward of the valve rod relative to the secondary seal, which further prevents fluid leakage around the valve rod. ..

As a device provided with such a plurality of seal structures, for example, butterfly valves of Patent Documents 1 and 2 are disclosed. In Patent Document 1, the resin seat ring is held by a support provided on the inner peripheral side, and the diameter of the valve body is larger than that of the resin seat ring. As a result, the resin seat ring is compressed and the upside-down seal functions, while the ring-shaped member, which is the seal member, is stopped by the washer held by the shoulder formed in the body hole. The seal is working.
In Patent Document 2, the cushion provided between the body and the resin seat ring functions as an up-and-down seal, and the clamp device provided on the secondary side in the axial direction of the up-and-down seal portion functions as the up-and-down seal. Has become.
As described above, in these valves, the up-and-down seal that is the primary seal and the first shaft seal for the valve rod that is the secondary seal are provided with independent structures, and the up-and-down seal and the shaft seal are provided by the respective seal parts. And a seal is provided.

On the other hand, in the butterfly valves of Patent Documents 3 to 5, the vertical seal is provided in a structure in which the pressing force of the spring is used.
In the butterfly valve of Patent Document 3, the cylindrical plug is elastically urged toward the boss portion side by the spring, thereby performing the up-and-down seal which is the primary seal between the resin seat ring and the valve body, and the cylindrical plug and the resin. A shaft seal, which is a secondary seal, is provided by an O-ring provided between the seat ring and the seat ring.
In the butterfly valve of Patent Document 4, the pressing ring is pressed by the disc spring, and the seal ring pressed by the pressing ring functions as an upside down seal and a shaft seal.
In Patent Document 5, an elastic body that is a seal member is axially pressed through a bearing member that is pressed by a spring, and the elastic body functions as a top and bottom seal and a shaft seal.

Further, in the butterfly valve 1 shown in FIG. 9 as a comparative example, a metallic core body 2 is covered with a resin lining layer 3 to provide a disc-shaped valve body 4, and a resin body is provided on the inner peripheral surface of the valve box 9. The seat ring 5 is attached. Further, the resin lining layer 3 is axially extended along the valve rod 6 mounted on the valve body 4 to form the valve rod cover portion 7, and the resin seat ring 5 is formed on the outer peripheral surface of the valve rod cover portion 7. Since the extended coating portion 8 extending along the valve rod 6 is arranged, it is intended to secure the sealing property.

By the way, in a butterfly valve, it is known that when fluid pressure is applied from the primary side in a valve closed state, the valve body slightly moves to the secondary side due to this fluid pressure. For example, in a butterfly valve having a nominal diameter of 100 A, when water pressure of 1.0 MPa is applied from the primary side in the valve closed state, the valve body moves to the secondary side by about 0.2 mm.

JP-A-52-90815 Japanese Patent No. 3863563 JP-A-61-119881 Japanese Utility Model Publication No. 58-56463 Japanese Patent No. 2920364

In the butterfly valves of Patent Documents 1 and 2, both top and bottom seals and shaft seals are provided independently of the springs, and in Patent Document 1, the diameter of the valve element is larger than the resin seat ring inner diameter. The cushion provided between the body and the resin seat ring allows the top and bottom seals to function respectively. Due to this structure, if the sealing performance deteriorates due to deterioration of the lining resin due to temperature changes or aging, the upside-down seal should be restored by using the elastic force of the spring against this deterioration of sealing performance. I can't. As a result, it is difficult to maintain the vertical sealability and the shaft sealability.

On the other hand, in the butterfly valves of Patent Documents 3 to 5, it is possible to recover the up-and-down seal by the elastic force of the spring by the up-and-down seal using the spring, but each has the following problems.
The butterfly valve of Patent Document 3 has a structure in which an O-ring is used for the secondary seal, and when a rubber material is used for this O-ring, it cannot be used for corrosive fluid such as chlorine. Therefore, the secondary seal cannot be secured, which leads to the limitation of the use of the valve.
In the butterfly valve in Patent Document 4, since the pressing force of the disc spring is divided into the vertical sealing direction and the axial sealing direction by the tapered surfaces provided on the pressing ring and the seal ring, the seal on either side is sealed. If the force is increased, the sealing property on the other side is weakened, and the sealing force on both sides cannot be effectively increased. In addition, it is also necessary to make an adjustment to keep the upside-down seal and the shaft seal in a well-balanced manner, which makes the adjustment difficult.
Also in Patent Document 5, since the pressing force of the spring is divided into the primary seal and the secondary seal by utilizing the tapered surface of the elastic body, there is the same problem as in Patent Document 4.

Further, in the butterfly valve 1 shown in Patent Documents 1 to 5 and as a comparative example in FIG. 9, for example, when the butterfly valve 1 in FIG. 9 is fully closed, a fluid pressure is applied from the primary side to the valve as shown in the figure. When the body 4 moves to the secondary side, the resin lining layer 3 also moves to the secondary side. In this case, the top and bottom sides of the resin lining layer 3 deviate to the secondary side with respect to the resin seat ring 5, and the adhesion between them deteriorates, and the top and bottom sides of the valve body 4 formed by the resin lining layer 3 and the resin seat ring 5 The sealability with the valve box 9 around the side valve rod 6, that is, the top-bottom sealability may be deteriorated, and so-called primary leakage may occur.
Further, in FIG. 9, the valve rod 6 moves to the secondary side with the movement of the valve body 4, so that the adhesion between the valve rod covering portion 7 and the extension covering portion 8 deteriorates, and the valve rod covering portion 7 The sealability between the valve stem 6 and the valve casing 9 formed by the extension cover 8 and the valve sheath 9, that is, the axial sealability of the valve stem 6 may deteriorate, and so-called secondary leakage may occur.

The present invention was developed in order to solve the conventional problems, and an object thereof is a lining type butterfly valve having corrosion resistance to a fluid, which improves the upside-down sealing property and the shaft sealing property at the same time. It is an object of the present invention to provide a butterfly valve capable of reliably preventing leakage and maintaining the sealing performance even if the disc moves to the secondary side due to fluid pressure.

In order to achieve the above object, the invention according to claim 1 is a butterfly valve in which a disk covered with a lining portion is provided in a tubular body covered with a seat liner via a stem so that the disk can be opened and closed. By sandwiching the seal portion between the ring body and the stem, the diameter of the shaft seal portion is prevented from expanding, and the elastic force of the spring provided in the shaft mounting portion of the body causes the boss of the disc to be held up and down via the ring body. While maintaining the sealability of the top-and-bottom seal portion by pressing the sheet liner located on the surface, an annular thick seal portion is formed on the inner circumference of the tubular lining portion extended to the seat liner, This is a lining type butterfly valve in which this thick-walled seal portion is pressed against the outer circumference of a shaft cylinder lining portion extending to the lining portion of the disc.

The invention according to claim 2 is a lining-type butterfly valve in which the top-bottom seal portion strongly presses a position near the outer periphery of the top-bottom seal boss surface of the disk.

According to a third aspect of the invention, the ring body is a lining type butterfly valve in which the seat liner is pressed through the annular flange portion of the sealing bush provided at the shaft seal portion.

The invention according to claim 4 is a lining type butterfly valve in which a bottom surface of an annular collar portion is provided with a tapered surface which is inclined downward toward an outer diameter.

The invention according to claim 5 is a lining type butterfly valve in which a thick seal portion is formed with a tapered surface portion having a mountain-shaped cross section.

The invention according to claim 6 is a lining type in which a cylindrical portion formed in a sealing bush is interposed between the tubular lining portion and the ring body, and the ring body prevents expansion of the diameter of the cylindrical lining portion through the cylindrical portion. It is a butterfly valve.

The invention according to claim 7 is a lining type butterfly valve in which an O-ring inserted in a cylindrical portion of a sealing bush is in sliding contact with a tubular lining portion of a seat liner.

The invention according to claim 8 is a lining type butterfly valve in which a stem and a disc are separately formed.

According to a ninth aspect of the present invention, the flow passage port and the flange portion of the short tubular body are covered with a seat liner, and when the disc and the stem slightly move to the secondary side due to the fluid pressure when fully closed, the seat It is a lining type butterfly valve in which a moving space in which a liner can follow and move is provided at an edge position on the flow path side of a flange part.

According to a tenth aspect of the present invention, the lining portion includes a boss surface that covers the upper and lower boss portions of the disc, and a shaft tube lining portion that covers the outer circumference of the stem from the boss surface, and the seat liner includes a flange portion. A sealing surface for extending the flow path and sealingly connecting to the boss surface and a cylindrical lining portion for sealing connection from the sealing surface to the outer periphery of the shaft cylindrical lining portion are vertically extended, and to the secondary side of the disc. Following the movement, the passage space of the seat liner moves due to the movement space, so that the up-and-down seal between the boss surface and the seal surface and the axial seal between the shaft tubular lining portion and the tubular lining portion are maintained. It is a lining type butterfly valve.

The invention according to claim 11 is the lining type butterfly valve, wherein the moving space is a tapered surface formed by cutting out the edge portion of the flow path opening of the body on the end face side of the body.

The invention according to claim 12 is the lining type butterfly valve, wherein the moving space is a step surface formed by cutting out an edge portion of the flow path opening of the body in a step shape.

The invention according to claim 13 is the lining butterfly valve, wherein the moving space is a tapered taper space provided in a connecting portion between the flow path portion and the flange end portion of the seat liner.

According to the invention of claim 1, the tubular body covered with the sheet liner and the disc covered with the lining portion have corrosion resistance against a fluid, and the top and bottom of the disc through the ring body by the elastic force of the spring. By pressing the seat liner located on the boss surface of the stem to maintain the sealability of the top-bottom seal part, the top-bottom seal part that is the primary seal is improved, and at the same time, the stem shaft seal part is replaced with the ring body. The shaft sealability can be improved by being sandwiched between the stem and the stem to prevent the shaft seal portion from expanding in diameter. In this case, the upside-down sealing property and the shaft-sealing property do not adversely affect each other, and both are retained to reliably prevent leakage. Moreover, since the ring body can be commonly used to secure the vertical sealability and the shaft sealability, an increase in the number of parts can be suppressed and the internal structure can be simplified. Since the up-and-down sealing property is maintained by utilizing the elastic force of the spring, the sealing property can be restored even when the resin, which is the lining material, deteriorates due to temperature changes or aging changes. At the time of assembly, since the up-and-down sealing property and the axial sealing property can be improved to a predetermined sealing force by mounting the ring body, it is not necessary to adjust each sealing force and the ring body can be easily assembled. By pressing the annular thick seal portion formed on the inner circumference of the tubular lining portion against the outer circumference of the shaft cylinder lining portion extended to the disc lining portion, when the stem is inserted into the shaft cylinder lining portion. The thick seal portion is brought into pressure contact with the outer diameter side of the shaft tube lining portion, and a pressing force in the radial direction is applied to the thick seal portion so that the thick seal portion comes into close contact with the thick seal portion, whereby a shaft seal state of the shaft seal portion is obtained. In this case, since the annular thick seal portion is pressed against the tubular lining portion, a locally high sealing property is obtained, so that leakage between the tubular lining portion and the shaft tubular lining portion is prevented. The shaft sealability can be ensured while reducing the frictional resistance to suppress the increase in the valve opening/closing operation torque.

According to the second aspect of the present invention, by strongly pressing the vicinity of the outer periphery of the seal boss surface on the top and bottom of the disc, the sliding resistance of the contact portion between the seal boss surface and the seat liner is reduced, and the opening/closing operation torque of the valve is reduced. The up-and-down sealing property can be improved while preventing the rising, and this up-and-down sealing property can be maintained by using a spring.

According to the third aspect of the present invention, the pressing force of the spring is transmitted from the ring body to the seat liner via the annular flange portion, which is different from the case where the metal ring body directly presses the resin seat liner. Prevents local deformation of the liner, prevents damage to this seat liner, and maintains upside-down sealing performance.

According to the fourth aspect of the present invention, the taper surface reliably and strongly presses the vicinity of the outer periphery of the seal boss surface of the top and bottom of the disk to secure the top and bottom sealability.

According to the invention of claim 5, since the tapered surface portion having the mountain-shaped cross section is formed, the boundary portion between the tapered surface portion and the tubular lining portion expands in a skirt shape, and the stress caused by the pressing with the axial tubular lining portion is reduced. It becomes easy to disperse. Therefore, local deformation of the thick-walled seal portion is suppressed, the creep phenomenon is also reduced to prevent the sealability from being reduced, and the shaft sealability is maintained to surely prevent leakage.

According to the invention of claim 6, the elastic force of the cylindrical portion of the sealing bush can be used to press the tubular lining portion against the outer periphery of the axial tubular lining portion to maintain the axial sealability.

According to the invention of claim 7, while adopting the up-and-down seal structure using the spring, the sealing bush used for the up-and-down seal can be used for preventing the diameter expansion of the tertiary seal portion by the O-ring, so that the sealing bush can be used for common parts. It is possible to maintain the shaft sealability by improving the tertiary sealability while improving the performance.

According to the invention of claim 8, the sealability of the shaft seal portion can be secured only by inserting the lining disc into the tubular body covered with the sheet liner and then inserting the stem into the disc. For this reason, the whole assembling work becomes easy, and by making the stem a separate body, it is possible to make the disc compact and secure the upside-down sealing property and the shaft sealing property.

According to the invention of claim 9, even when the disc moves to the secondary side due to fluid pressure when the valve is closed, the seat liner can be moved following the movement space, and the seat liner and the lining portion can be moved. By preventing primary leakage between the two and maintaining vertical sealability, and by preventing secondary leakage and maintaining axial sealability, it is possible to reliably close highly corrosive fluids, chemical fluids such as chlorine gas, and fluids such as chemicals. .. Moreover, since it is only necessary to provide a moving space for the seat liner, workability and formability are excellent, and the seat liner, the lining portion, and the body shape can be manufactured while suppressing complication. Further, since the thickness of the seat liner and the disclining can be secured, the fluid permeation resistance can be maintained.

According to the tenth aspect of the invention, the passage space of the sheet liner is moved by the movement space following the movement of the disc to the secondary side, so that the boss surface and the axial cylinder lining are moved to the secondary side together with the disc. The sealing state and the tubular lining portion can be made to follow the portion to maintain the sealed state. This prevents the primary leakage between the boss surface and the sealing surface to maintain the vertical sealing property between the body and the disc, and prevents the secondary leakage between the shaft cylinder lining portion and the tubular lining portion. It is possible to reliably prevent fluid leakage by maintaining the shaft sealability with the disk.

According to the invention of claim 11, the flow passage portion of the seat liner can be deformed without being restricted, and the flow passage portion can be smoothly deformed along the tapered surface when the disc and the stem move to the secondary side. Thus, the seat liner can be followed, and stress concentration at the contact portion of the seat liner with the body can be prevented. Since the moving space can be easily formed in the body due to the tapered surface, the sheet liner does not need to be processed and the formability improves, and since it is not necessary to reduce the thickness of the sheet liner, it is resistant to permeation of fluids such as chlorine. Sex can also be maintained.

According to the twelfth aspect of the present invention, the step portion surface can be formed by simple processing without requiring high accuracy on the body side, and the flow passage portion of the seat liner is connected to the secondary side of the disc and the stem through the step portion surface. It can be surely deformed so as to follow the lateral movement. As a result, the sheet liner does not need to be processed, so that the moldability is good, and since it is not necessary to reduce the thickness of the sheet liner, the permeation resistance to a fluid such as chlorine can be maintained.

According to the thirteenth aspect of the present invention, since the taper space can be provided at the same time as the sheet liner is formed without processing the body, it is possible to suppress an increase in the number of working steps for forming the taper space. The flow passage portion of the seat liner can be surely deformed so as to follow the secondary side movement of the disc and the stem via the taper space.

It is a central longitudinal cross-sectional view showing an embodiment of a lining type butterfly valve of the present invention. It is a center longitudinal cross-sectional view of the lining type butterfly valve of FIG. It is a principal part expanded sectional view of FIG. FIG. 6 is a partially enlarged cross-sectional view showing the vicinity of a thick seal portion. It is a partially expanded sectional view which shows the sealing bush vicinity. It is a principal part expanded sectional view which shows the state which the disc of FIG. 3 moved to the secondary side. It is a principal part expanded sectional view which shows 2nd Embodiment of the lining type butterfly valve of this invention. It is a principal part expanded sectional view which shows 3rd Embodiment of the lining type butterfly valve of this invention. It is a principal part expanded sectional view which shows the conventional rose fly valve.

10 valve body 11 body 12 disk 13 stem 15 flow path port 16 flange part 18 shaft seal part 19 top and bottom seal part 20 seat liner 22 ring body 23 sealing bush 23a cylindrical part 23b annular collar part 24 O-ring 26 taper surface 27 shaft mounting part 30 Flow path portion 31 Sealing surface 32 Lining portion 33 Shaft cylinder lining portion 34 Cylindrical lining portion 36 Boss portion 37 Boss surface 40 Tapered surface (moving space)
42 thick seal part 43 taper surface part 44 spring 51 step surface (moving space)
61 Taper space (moving space)

Embodiments of a lining type butterfly valve according to the present invention will be described below in detail with reference to the drawings. 1 and 2 show an embodiment of the butterfly valve of the present invention, and FIG. 3 shows an enlarged cross-sectional view of the main part of FIG.

1 and 2, a butterfly valve (hereinafter, referred to as a valve body 10) is used, for example, in a chemical industry plant, a food-related pipeline or the like, and has a cylindrical body 11, a disc 12, an upper stem 13a, and It has a stem 13 composed of a lower stem 13b and is provided with a nominal diameter of 100A. As will be described later, in the valve body 1, a tubular lining portion 34 of the seat liner 20, a shaft tubular lining portion 33 of the lining portion 32, a shaft seal portion 18 having a sealing bush 23, a boss surface 37 of the lining portion 32, and a seat. An upside-down sealing portion 19 having a sealing surface 31 of the liner 20 is provided.

The body 11 is formed into a tubular shape from cast iron such as ductile cast iron, and has an upper body 11a and a lower body 11b, which are detachably fixed with bolts 14. A flow passage port 15 and a flange portion 16 are provided in the body 11, and these are covered with a sheet liner 20. A shaft mounting portion 27 having a shaft mounting hole 21 is provided on the shaft mounting side of the stem 13 of the upper body 11a and the lower body 11b, and the shaft mounting portion 27 is mounted with the upper stem 13a and the lower stem 13b, respectively. A ring body 22, a sealing bush 23, an O-ring 24, and a bearing 25 are mounted on the disk 12 mounting side of the shaft mounting portion 27, and a spring 44 formed of a coil spring is provided subsequent to these.

The seat liner 20 is made of a resin material. In this embodiment, the seat liner 20 is provided with a fluororesin such as PFA (tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer) to have a wall thickness of, for example, about 3 mm, which results in high corrosion resistance and heat resistance. It is possible to exert the ability. In the seat liner 20, a flow passage portion 30 that is movable in the flow passage direction is formed on the flow passage port 15 side, and further, the flow passage portion 30 is extended from the flange portion 16 to seal on the inner peripheral side. A surface 31 is provided, and a cylindrical lining portion 34 that can be seal-connected from the sealing surface 31 to an outer periphery of a shaft cylinder lining portion 33 described below extends in the axial direction of the upper and lower shaft mounting holes 21.

In FIGS. 3 and 4, the tubular lining portion 34 is formed of a tubular portion and is integrally extended to the seat liner 20 on the side where the stem 13 is inserted. The seal portion 42 is formed.

The thick seal portion 42 is provided so as to project in a size capable of pressing the outer periphery of the shaft tube lining portion 33.
The thick seal portion 42 is formed with a tapered surface portion 43 having a mountain-shaped cross section, and the taper angle of the tapered surface portion 43 is set in the range of 8° to 15°, for example. The thick-walled seal portion 42 is in pressure contact with the outer diameter side of the shaft tube lining portion 33 when the stem 13 is inserted into the shaft tube lining portion 33 while being in contact with the outer periphery of the shaft tube lining portion 33. By doing so, the shaft seal state of the shaft seal portion 18 is obtained.

1 to 3, the disc 12 is formed separately from the stem 13 and is rotatably provided in the body 11 via the stem 13. A cored bar 35 is provided on the center side of the disk 12, and the cored bar 35 is formed into a disc shape using, for example, a stainless alloy material. Similarly, the lining portion 32 made of a resin material such as PFA or the like such as a fluororesin is covered with a thickness of 3 mm, for example.

The lining portion 32 includes a boss surface 37 covering a boss portion 36 formed on the peripheral surface of the stem insertion hole 12a formed above and below the disk 12 on the upside and downside of the disk 12, and an outer circumference of the stem 13 from the boss surface 37. And a shaft cylinder lining portion 33 composed of a shaft seal side shaft cylinder portion extending so as to cover the core metal 35 through a through hole 35a formed at an appropriate position of the core metal 35. By being integrally covered on the outer periphery, separation from the cored bar 35 is prevented.

A square hole 38 is formed on the top and bottom sides of the stem insertion hole 12a of the disk 12, and the connection side of the upper stem 13a and the lower stem 13b is inserted and fitted through the square hole 38 to connect the upper stem 13a and the lower stem 13b. The disc 12 covered with the lining portion 32 is rotatably mounted on the body 11 covered with the sheet liner 20. By thus providing the stem 13 and the disc 12 in a separate structure, the assembly becomes easy.

A cylindrical bearing 25 is provided on the outer peripheral side of the stem 13 of the shaft mounting hole 21, and a metallic cylindrical ring body 22 is sandwiched between the bearing 25 and the seat liner 20 located below. It is provided as follows.

The ring body 22 is made of a stainless steel material and has a diameter capable of strongly pressing the outer peripheral vicinity of the seal boss surface 37 of the disk 12 from above, and the disk body 12 is rotatably mounted via the bearing 25. The elastic force of the spring 44 of FIG. 1 is provided so as to be transmitted.

In FIG. 1, a bearing member 70 is arranged in the shaft mounting hole 21 of the upper body 11a in a state of being locked by a holding ring 71, and the spring 44 is supported by the bearing member 70 so as to be elastically downward. It On the other hand, a top member 72 is arranged in the shaft mounting hole 21 of the lower body 11b in a state of being locked by a holding ring 71, a bearing member 73 is superposed on the top member 72, and the bearing member 73 is interposed therebetween. The spring 44 is supported in a state of being capable of elastically rebounding upward. The upper and lower springs 44, 44 are repelled in the disk 12 direction by the bearing members 70, 73 and the top member 72, respectively. On the inner and outer circumferences of the bearing member 70 and the top member 72, dust-proof and waterproof O-rings 74 and 75 are mounted, respectively.

The bearing 25 is disposed between the spring 44 of the shaft mounting hole 21 and the ring body 22, and the bearing 25 allows the upper stem 13a and the lower stem 13b to rotate freely near the tertiary seal (near the O-ring 24). Moreover, it is supported in an aligned state. The bearing 25 is provided in a two-layer structure in which a resin bushing 25b with a back metal is mounted on the inner circumference of a bearing bush 25a made of metal such as stainless steel.

The bearing bush 25a is provided on the outer diameter to which the spring 44 abuts and the elastic force is applied. When the elastic force is applied, the end surface side abuts the ring body 22 and presses the ring body 22 to the disc 12 side. It is possible. In this case, the end surface of the bearing bush 25a on the disk 12 side may be in contact with the end surface of the sealing bush 23, but it is not necessary to apply a pressing force from the bearing bush 25a to the sealing bush 23.

In the present embodiment, a slight gap (not shown) is provided between the lower surface of the bearing bush 25a and the upper surface of the sealing bush 23 so that the sealing bush 23 is not pressed by the bearing 25. .. The ring body 22 may be directly pressed by the spring 44 without using the bearing 25.

The sealing bush 23 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 22 of the shaft mounting hole 21, the lining portion 32 and the seat liner 20. Is provided as. In FIG. 3, a cylindrical portion 23a is formed in the sealing bush 23, and a collar portion 23b formed of an annular collar portion is formed on the lower side of the cylindrical portion 23a so as to be bent in the outer peripheral direction. The end surface 22a of the ring body 22 abuts on the collar portion 23b, and thus the ring body 22 presses the seat liner 20 via the collar portion 23b.

According to this structure, even if the valve is harshly used or the like, the sealing performance of the top-bottom sealing portion 19 and the shaft sealing portion 18 is deteriorated, and even if a fluid enters between the seat liner 20 and the sealing bush 23. Since the collar portion 23b of the resin sealing bush 23 is strongly pressed against the resin sheet liner 20 by the ring body 22, this pressed portion prevents so-called back leakage. Therefore, the metal ring body 22 does not come into contact with the corrosive fluid, the elastic force of the spring 44 is increased, and the seat liner 20 is pressed through the ring body 22 to restore the top-bottom seal.

Here, as shown in FIG. 5, the bottom surface of the collar portion 23b is provided with a tapered surface 26 that is inclined downward toward the outer diameter at an angle θ, whereby the sealing bush 23 of FIG. When mounted, the vicinity of the outer diameter portion of the bottom surface of the collar portion in FIG. 5 may be brought into contact with the seat liner 20.

Further, although not shown, when the fluid is not corrosive, an annular flange portion of the ring body 22 is formed so that the lower side of the ring body 22 is bent in the inner circumferential direction, and the seat liner 20 is directly connected to the ring body 22. A pressing structure may be used. In this case, the sealing bush 23 does not require the collar portion 23b, and the cylindrical portion 23a may be arranged above the annular collar portion of the ring body 22.

The sealing bush 23 is mounted so that the cylindrical portion 23a is interposed between the cylindrical lining portion 34 and the ring body 22, and the ring body 22 prevents the diameter expansion of the cylindrical lining portion 34 through the cylindrical portion 23a. It

With such a configuration, in the valve body 10 shown in FIG. 1, the spring 44 provided in the shaft mounting portion 27 of the body 11 is elastically positioned on the boss surface 37 of the disk 12 via the ring body 22. By pressing the sheet liner 20 to be held, the sealing property of the top-and-bottom sealing portion 19 as the primary seal is maintained.

At the same time, the shaft seal portion 18 having the tubular lining portion 34, the shaft cylinder lining portion 33, and the sealing bush 23 of the stem 13 is sandwiched between the ring body 22 and the stem 13 to expand the diameter of the shaft seal portion 18. The shaft seal portion 18, which is the sliding contact portion, functions as a secondary seal.

Further, in FIG. 3, a holding portion 23c is provided above the cylindrical portion 23a of the sealing bush 23, and the O-ring 24 is inserted into the holding portion 23c. As a result, the O-ring 24 is mounted above the shaft seal portion 18 (secondary seal), and the O-ring 24 is brought into sliding contact with the shaft cylinder lining portion 33, and these shaft cylinder lining portions 33 (the upper stem 13a and the lower stem 13a). The sliding contact portion between 13b) and the O-ring 24 functions as a tertiary seal. The holding portion 23c is provided at such a height that the gap X can be formed between the holding portion 23c and the tubular lining portion 34.
Although FIG. 3 shows the vicinity of the upper side of the disc 12 in the valve body 10, the lower side of the disc 12 is also provided with the same structure as the upper side.

Although the ring body 22 is made of stainless steel in the above embodiment, it may be made of a metal material other than this, or when it is pressed by the bearing 25, the ring body 22 side (outer circumference of the disc 12). A material other than a metal material may be used as long as it can strongly press (in the vicinity).

Further, although the coil spring is used as the spring 44, the present invention is not limited to this, and a disc spring may be used as the spring, for example.

Next, the procedure for assembling the valve body will be described. When assembling the valve body 1, the upper and lower sides are similarly assembled.
In FIGS. 1 and 2, first, the disc 12 covered with the lining portion 32 is incorporated inside the seat liner 20. At this time, the upper and lower axial tube lining portions 33 of the disc 12 are inserted into the tubular lining portions 34 of the seat liner 20, respectively.

Next, the sealing bush 23 in which the O-ring 24 is attached to the holding portion 23c is attached to the outer circumference of the tubular lining portion 34. At this time, the collar portion 23b is fitted into the outer peripheral side of the tubular lining portion 34, and the O ring 24 on the upper side in FIG.

The ring body 22 is attached to the outer circumference of the sealing bush 23 while the bottom surface is in contact with the upper surface of the collar portion 23b. As a result, the metal ring body 22 holds the cylindrical portion 23a and the holding portion 23c of the sealing bush 23 from the outer peripheral side, and the diameter expansion of the thick seal portion 42 of the tubular lining portion 34 is prevented.

In this state, the upper stem 13a and the lower stem 13b are respectively inserted inside the barrel lining portion 33 and connected to the stem insertion hole 12a. As a result, a predetermined pressing force is applied to the thick seal portion 42 in the radial direction, so that the secondary seal and the tertiary seal can function.

On the other hand, the bearing 25, the spring 44, the bearing members 70 and 73, and the top member 72 are attached to the shaft mounting holes 21 of the upper body 11a and the lower body 11b at the corresponding positions, respectively. The retaining ring 71 is locked to prevent the retaining ring 71 from slipping out.

Finally, the above-mentioned seat liner 20 having the disc 12, the sealing bush 23, and the ring body 22 mounted is arranged between the upper body 11a and the lower body 11b, and the bolt 14 is tightened while sandwiching the sheet liner 20 to integrate them. The assembly of the valve body 10 is completed.

In FIG. 6, when fluid pressure is applied to the assembled valve body 10 from the primary side when the valve body 10 is fully closed, the disc 12 and the stem 13 are slightly moved to the secondary side by this fluid pressure. When a fluid pressure of 0.0 MPa is applied, the disc 12 moves to the secondary side by about 0.2 mm. In the valve body 10, a moving space 40 that can be moved by the seat liner 20 when the disc 12 is moved is formed on the edge of the flange portion 16 on the side of the flow passage portion 30 as shown in FIG. It is provided at the part position.

By the movement of the flow passage portion 30 of the seat liner 20 following the movement of the disc 12 to the secondary side by the movement space 40, the up-and-down seal between the boss surface 37 and the seal surface 31, the shaft cylinder lining portion 33, and the tubular shape. The sealing performance with the shaft sealing performance with the lining portion 34 is maintained.

The moving space 40 is provided by a tapered surface formed by cutting out the edge portion of the flow passage port 15 of the body 11 on the end face side of the body 11, and the flow passage portion 30 can be deformed within the range of the moving space 40. Has become. Therefore, in the tapered surface 40, the flow path portion 30 can move to the secondary side following the disc 12 to maintain the vertical seal and the shaft seal, and the lateral movement dimension in FIG. 3 is the maximum movement distance of the disc 12. Is provided at a predetermined angle. In this embodiment, as described above, the moving space 40 in which the disc moves laterally with the maximum width of 0.2 mm by the fluid pressure of 1.0 MPa is provided at an angle that can be secured between the body 11 and the seat liner 20. To be If the lateral movement dimension of the flow path portion 30 is too large, the flow path portion 30 may move too much, which may negatively affect the seal of the disk 12 on the valve blade side.

Further, it is also possible to adjust the angle of the tapered surface 40 to set the movement amount of the flow path portion 30, and by finely adjusting the movement amount with a very small amount, the valve body 10 to which different caliber or fluid pressure is applied. The amount of movement of the flow path portion 30 can be set in accordance with the above, and the vertical sealability and the axial sealability can be maintained.

The tapered surface 40 is formed along the flow path port 15 of the body 11 and has an outer diameter that is the same as the inner diameter of the gasket 41 shown in FIG. 3 that is arranged at a connection portion with an external pipe (not shown) connected to the valve body 10. It is set equal or less. As a result, the tapered surface 40 does not reach the sealing surface 41a of the gasket 41 in the flow path direction, and the flange portion of the seat liner 20 is affected even when fluid pressure is applied to the sealing surface 41a of the gasket 41. Since the gasket 41 is not deformed, the sealability of the gasket 41 with the external pipe can be maintained.

In this case, the right side is the upstream side and the left side is the downstream side in FIG. 2, but in the case of the valve body 1 having a bilaterally symmetrical structure as shown in the figure, the left side may be the upstream side and the right side may be the downstream side.
The moving space 40 described above does not necessarily have to be formed in the body 11 and may be formed in the seat liner 20. As described above, the moving space 40 may be provided on either one or both of the seat liner 20 and the body 11, and in any case, the moving space 40 may have various shapes other than the tapered surface. It can also be provided.

Next, the operation of the above-described embodiment of the lining type butterfly valve of the present invention will be described.
In FIG. 3, in the fully closed valve body (nominal diameter 100 A) 10, the elastic force of the spring 44 presses the seat liner 20 located on the boss surface 37 of the disk 12 via the ring body 22. The up-and-down sealing property which is the primary seal by the up-and-down sealing portion 19 having the boss surface 37 and the sealing surface 31 can be maintained, and even when the seat liner 20 and the lining portion 32 are deteriorated, the spring 44 is repulsed. The sealing property can be restored by force.

In this case, the elastic force of the spring 44 is transmitted as a pressing force via the ring body 22 to the outer peripheral side of the boss surface 37 on the top-bottom seal side of the disk 12. For this reason, the boss surface 37 and the seal surface 31 can be intensively brought into close contact with each other while suppressing an increase in the operating torque, and thus a predetermined sealing performance of the up-and-down seal can be obtained.

Since the shaft seal portion 18 is sandwiched between the ring body 22 and the stem 13 to prevent the diameter of the shaft seal portion 18 from being expanded, the shaft seal is a secondary seal without adversely affecting the vertical sealability. A shaft sealability due to the lining portion 33 and the tubular lining portion 34 can also be secured. As a result, it is possible to improve the sealing performance of both sides without lowering the sealing performance of either the upside-down sealing property or the shaft sealing property, and it is possible to suppress an increase in the number of parts.

Since the sealing surface 31 and the tubular lining portion 34 of the seat liner 20, the boss 37 of the lining portion 32, and the shaft tubular lining portion 33 are integrally molded of resin, respectively, they have excellent corrosion resistance against corrosive fluid such as chlorine. To maintain.

More specifically describing the sealing property of each seal portion, in the up-and-down seal portion 19, the ring bodies 22 concentrically arranged on the outer periphery of the upper stem 13a and the lower stem 13b are seated by the elastic force of the spring 44. The liner 20 is pressed to maintain the sealing property. At this time, since the top-bottom sealing portion 19 strongly presses the outer peripheral position of the top and bottom boss surface 37 of the disk 12, the disk 12 and the sheet liner 20 are compared with the case where the entire boss surface 37 is pressed. It is possible to maintain the primary sealability while reducing the sliding resistance with and to prevent the opening and closing operation torque of the valve from rising.

Moreover, since the sealing bush 23 is provided in the shaft seal portion 18 and the seat liner 20 is pressed through the flange portion 23b of the sealing bush 23, the end surface 22a of the ring body 22 directly presses the seat liner 20. Instead, the resin-made sealing bush 23 presses, and the pressing force from the ring body 22 is transmitted via the flange portion 23b so as to be dispersed to the seat retainer 20 side, and stress concentration is prevented. Therefore, local deformation of the seat liner 20 can be prevented as compared with the case where the metal ring body 22 is directly pressed.

Further, by strongly pressing the flange portion 23b and the sheet liner by the ring body 22, these contacting portions also function as sealing portions, and the pressing portions function as portions that prevent leakage called back leakage as described above.

Here, as shown in FIG. 5, a taper surface 26 having an angle θ is provided on the bottom surface of the flange portion 23b so as to descend and incline, and the outer peripheral side of the disk 12 is more concentrated on the outer diameter side of the taper surface 26. By pressing strongly in an annular shape, it is possible to further improve the vertical sealing property.

On the other hand, at the shaft seal portion 18, the tubular lining portion 34 and the shaft tubular lining portion 33 are in sliding contact with each other, and at this time, the thick seal portion 42 on the inner circumference of the tubular lining portion 34 is on the outer circumference of the shaft tubular lining portion 33. It works by being pressed by. This makes it possible to locally obtain a high sealing property and prevent leakage between the tubular lining portion 34 and the shaft tubular lining portion 33. Since the thick seal portion 42 is a resin integrally formed with the tubular lining portion 34, these secondary seals are in sliding contact with each other. Therefore, if a resin material having a small friction coefficient such as a fluororesin is used as these materials, the frictional resistance is increased as compared with the case where the resin cylindrical lining portion 34 is directly pressed against the metal stem 13. Can be significantly reduced to prevent the valve opening/closing operation torque from rising.

By forming the tapered surface portion 43 having a mountain-shaped cross section in the thick seal portion 42, the boundary portion between the tapered surface portion 43 and the tubular lining portion 34 spreads in a skirt shape, and is pressed against the shaft tubular lining portion 33. It is easy to disperse the accompanying stress. This suppresses local deformation of the thick-walled seal portion 43, reduces the creep phenomenon, and prevents the sealability from being reduced. When the stem 13 is attached to the disc 12, the stem 13 can be smoothly passed over the thick seal portion 42 and inserted into the disc 12. When the seat liner 20 is manufactured, the thick seal portion 42 protrudes inward of the tubular lining portion 34, but there is no fear of obstructing the removal of the molding die due to the cross-sectional mountain shape of the tapered surface portion 43.

As described above, in order to sandwich the shaft seal portion 18 and prevent the thick seal portion 42 from expanding in diameter by the ring body 22 to maintain the sealing performance of the secondary seal, the ring body 22 is provided as in this embodiment. It may be arranged at a position facing the thick seal portion 42. In the present embodiment, in FIG. 4, the height of the disc-side end portion 42a of the thick-walled seal portion 42 is set to substantially match the height of the end surface 22a of the ring body 22.

A cylindrical portion 23a is interposed between the tubular lining portion 34 and the ring body 22, and the ring body 22 prevents the cylindrical lining portion 34 from expanding in diameter through the cylindrical portion 23a. The shaft sealability is further improved by positively pressing the shaft lining portion 33 against the shaft 42 and also utilizing the elastic force of the resin cylindrical portion 23a.

On the tertiary seal side, the O-ring 24 inserted in the cylindrical portion 23a of the sealing bush 23 is slidably in contact with the tubular lining portion 34 of the seat liner 20, so that the O-ring 24 is separated from the upper stem 13a and the lower stem 13b. It is possible to prevent the tertiary leakage from the periphery of the stem 13 by ensuring the sealing property by sliding it on the outer periphery with a predetermined pressing force. In addition, since the holding portion 23c is housed in the ring body 22, the ring body 22 is also used to prevent the diameter expansion of the holding portion 23c, and the shaft sealability can be further improved while sharing components.

Moreover, the tertiary sealing function of the O-ring 24 around the stem 13 can prevent tertiary leakage around the stem even when the disc 12 moves to the secondary side due to fluid pressure, and the sealing bush 23 allows common use of parts. , It exerts its tertiary sealing function while preventing stress concentration.

In FIG. 3, when a fluid pressure of 1.0 MPa is applied to the valve body (nominal diameter 100 A) 10 when fully closed from the primary side (right side in the figure), the disc 12 and the stem 13 are about 0.2 mm square. Move slightly to the next side (left side in the figure).

Here, the seat liner 20 has a sealing surface 31 that seals with the boss surface 37 that covers the boss portion 36 of the disc 12 to form an upside-down seal, and the tubular lining portion 34 of the seat liner 20 forms the outer circumference of the stem 13. Since the shaft seal is formed by sealing the shaft cylinder lining portion 33 that covers the inner surface of the seat liner 20, the flow passage portion 30 of the seat liner 20 has a sealing surface along with the movement of the disc 12 and the stem 13 to the secondary side. A force that moves to the secondary side together with 31 and the tubular lining portion 34 is applied.

At that time, since the body 11 is previously provided with the moving space 40 having a width of 0.2 mm at the edge position of the flange portion 16 on the side of the flow passage portion 15, the flow passage portion 30 of the seat liner 20 is As shown in FIG. 6, it can be deformed within the range of the moving space 40 (maximum width 0.2 mm), and moves 0.2 mm to the secondary side following the movement of the disc 12 and the stem 13 to the secondary side. can do.

Therefore, the upside-down seal by the boss surface 37 and the sealing surface 31, and the shaft seal by the tubular lining portion 34 and the axial tube lining portion 33 formed in the direction orthogonal to the flow passage portion 30 of the seat liner 20, respectively. The sealing property of can be maintained. As a result, it is possible to prevent primary leakage on the top and bottom seal side and secondary leakage on the shaft seal side.

Moreover, since the moving space is provided by the taper surface 40 formed by cutting the edge portion of the flow passage port 15 of the body 11 toward the end face side of the body 11, the flow passage portion 30 of the seat liner 20 can be formed while the stress concentration is prevented. Since the seat liner 20 can be moved, it is possible to suppress wear of the seat liner 20.

Furthermore, by mounting the O-ring 24 on the inner circumference of the cylindrical portion 23a of the collar-shaped member 23, it is possible to prevent tertiary leakage between the collar-shaped member 23 and the shaft tube lining portion 33.

Next, FIG. 7 shows a second 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 the valve body 50 in this embodiment, the edge of the flow passage port 15 of the body 11 is cut out in a stepped shape to form a circumferential stepped surface 51, and the stepped surface 51 forms the seat liner 20. There is a moving space that can be followed.
In this case, since the step surface 51 can be formed by notching the flange 16 on the body 11 side at a predetermined depth, the step surface 51 can be formed by simple processing without requiring high accuracy. .. At this time, by forming the step surface 51 as shallow as possible, stress concentration on the seat liner 20 near the boundary of the step surface 51 can be avoided.

FIG. 8 shows a third embodiment of the lining type butterfly valve of the present invention. In the valve body 60 of this embodiment, a tapered taper space 61 is formed so as to be cut out at a connection portion between the flow passage portion 30 of the seat liner 20 and the flange end portion, and the taper space 61 serves as a movement space. ing.
In this case, the taper space 61 can be formed on the sheet liner 20 side at a time without molding the body 11 at the time of molding, and more preferably, the taper space 61 can be formed so that the seat liner 20 is brought into close contact with the body 11. It is also possible to suppress the influence on the permeation resistance of the fluid.

Claims (13)

A butterfly valve in which a disk covered with a lining portion is provided in a tubular body covered with a seat liner so as to be openable and closable via a stem, and a shaft seal portion of the stem is sandwiched between a ring body and the stem. By preventing the diameter of the shaft seal portion from expanding and pressing the seat liner located on the top and bottom boss surface of the disk through the ring body by the elastic force of the spring provided in the shaft mounting portion of the body. An annular thick seal portion is formed on the inner periphery of the cylindrical lining portion extending in the seat liner while maintaining the sealing property of the top and bottom seal portion, and the thick seal portion is used as the disc lining portion. A lining type butterfly valve characterized in that it is pressed against the outer circumference of a shaft lining portion extended to the. The lining type butterfly valve according to claim 1, wherein the top-bottom seal portion strongly presses a position near an outer periphery of a top-bottom seal boss surface of the disc. The lining type butterfly valve according to claim 1 or 2, wherein the ring body presses the seat liner via an annular flange portion of a sealing bush provided at the shaft seal portion. The lining type butterfly valve according to claim 3, wherein the bottom surface of the annular flange portion is provided with a taper surface which is inclined downward toward the outer diameter. The lining type butterfly valve according to any one of claims 1 to 4, wherein the thick seal portion is formed with a tapered surface portion having a mountain-shaped cross section. The cylindrical portion formed on the sealing bush is interposed between the ring member and the tubular lining portion, to claim 3 which prevents diameter of the tubular lining portion through said cylindrical portion by said ring member Lining type butterfly valve described . 7. The lining type butterfly valve according to claim 6, wherein an O-ring inserted in the cylindrical portion is in sliding contact with a tubular lining portion of the seat liner.
The lining type butterfly valve according to any one of claims 1 to 7, wherein the stem and the disc are separately formed. When the disc line and the stem slightly move to the secondary side by the fluid pressure when fully closed, the sheet liner follows the flow passage port and the flange portion of the short tubular body. 9. The lining type butterfly valve according to any one of claims 1 to 8, wherein a movable space that can be moved is provided at an edge position on the flow path side of the flange portion. The lining portion includes a boss surface that covers the upper and lower boss portions of the disc and a shaft tube lining portion that covers the outer periphery of the stem from the boss surface, and the seat liner includes the flow passage from the flange portion. A sealing surface for extending and sealingly connecting to the boss surface and a cylindrical lining portion for sealingly connecting to the outer periphery of the shaft cylindrical lining portion from the sealing surface, and to the secondary side of the disc. The movement of the flow passage portion of the seat liner by the movement space following the movement of the above, the sealability between the upside-down seal between the boss surface and the seal surface and the shaft seal between the shaft cylinder lining part and the cylindrical lining part. The lining type butterfly valve according to claim 9, wherein The lining type butterfly valve according to claim 9 or 10, wherein the moving space is a tapered surface formed by cutting out an edge portion of a flow passage port of the body on an end face side of the body. The lining type butterfly valve according to claim 9 or 10, wherein the moving space is a step portion surface formed by cutting an edge portion of a flow passage port of a body into a step portion. The lining type butterfly valve according to claim 9 or 10, wherein the moving space is a tapered taper space provided in a connecting portion between a flow path portion of the seat liner and a flange end portion.

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