The present invention relates to a sealing structure of a butterfly valve, particularly to a sealing structure in the vicinity of the sealing portion of the valve blade and a valve box of the butterfly valve resin lining has been applied to the valve body and the valve box internal peripheral surface.

Background technique

[0002]

　Butterfly valve, sealability around the stem shaft wear part is ensured by the boss portion contact surface of the boss portion and the seat ring which is formed at the base of the stem shaft of the valve body, the Bentsubasa outer peripheral surface and the seat ring of the valve body circumferential face seal of the valve blade side of the stem shaft deposition part by the Bentsubasa contact surface is in the sealing structure is ensured. When using such a butterfly valve or when carrying high corrosive fluids used in chlorine production and plants for semiconductor manufacturing, chemical fluids such as chlorine gas or hydrochloric acid, a chemical solution, a solvent, such as food-related flow path the, resin lining the valve body fluid contacts and the valve body inner peripheral surface is often subjected. Fear as the resin lining material, but chemical resistance and excellent heat resistance fluorine resin is usually used, fluorine resin is the valve seat leakage decreases the circumferential surface seal of Bentsubasa side for poor elasticity occurs there is. Therefore, in order to increase the valve blade side of the seal of the butterfly valve, rubber ring is disposed on the back side of the resin lining material, elastic shortage around the valve blade by utilizing the elastic repulsive force of the rubber ring butterfly valve so as to improve the sealing property by compensating has been proposed in general.

[0003]

　As this type of butterfly valves, for example, a butterfly valve of Patent Document 1 is disclosed. This butterfly valve, a resin lining layer made of a fluorocarbon resin sheet ring provided on the inner surface of the valve body is a valve body made of rubber backup ring between the seat ring and the valve body is inserted, this sealing property between the resiliently force is exerted on the seal portion the valve body is secured by a backup ring. When providing a sealing structure of such a butterfly valve, a backup ring groove formed in the valve body which is mounted, seat ring through the backup ring is mounted to the body, followed by the seat ring is mounted the valve body through a stem to the valve body and is mounted.
　In this butterfly valve, when to rotate the valve body to press the valve blade side of the valve body seat ring by the stem operation, the seat ring is adapted to seal the valve body while being compressed in the outer diameter direction together with the backup ring there.

[0004]

　Similar techniques are also disclosed in Patent Document 2. In this butterfly valve, the radius of the outer periphery of the valve body, equal to the radius of the inner circumferential surface of the valve seat which is clamped in the radial direction by an elastic member made of rubber or the like ring-shaped, or than the radius of the inner peripheral surface of the valve seat are described fact also be set slightly larger.

CITATION

Patent literature

[0005]

Patent Document 1: Japanese Unexamined Patent Publication No. 2003-166654
Patent Document 2: Japanese Unexamined Patent Publication No. 2012-219819

Summary of the invention

Problems that the Invention is to Solve

[0006]

　However, in the butterfly valve of Patent Document 1, since it becomes necessary force to compress the seat ring itself in addition to the force against the elastic force of the back-up ring during valve closing seal had led to increase in the operating torque. In this case, to reduce the operating torque while ensuring the sealing performance if so reduce the compression of the seat ring is made can allow the shape and structure to suppress compression of such a seat ring is described and suggested It has not been. In addition, the force for causing the compression of the seat ring in the valve closed state, becomes larger as the thickness of the sheet ring is increased, the operating torque there is a problem that further increases. Therefore, in this type of butterfly valve, also difficult to the seat ring thickened provided to improve the chemical resistance and heat resistance.

[0007]

　On the other hand, in the butterfly valve of Patent Document 2, the radius of the inner circumferential surface of the valve seat, (see FIG. 2 of Patent Document 2) Since the elastic member corresponding to the backup ring indicates the size of the state of being mounted , at the time of valve closing seal, in addition to the force against the elastic force of the case as well as the back-up ring of Patent Document 1, a force to compress the sheet ring itself is also required.
　Further, both Patent Documents 1 and 2, the backup ring, since its thickness is smaller flat shape than the width dimension, requires improvement to smoothly contracted and enlarged the backup ring along with the opening and closing of the valve it is.

[0008]

　The present invention has been developed to solve the conventional problems, and an object, in particular while improving the sealing performance around Bentsubasa to suppress the force to compress the resin lining layer when the valve closing operation prevent the increase in the operating torque on, and to provide a seal structure of the opening and closing operable butterfly valve while securing the sealing property at a constant low operating torque even when increasing the thickness of the resin lining layer.

Means for Solving the Problems

[0009]

　To achieve the above object, the invention according to claim 1, provided with disuccinimidyl surface, the inner circumferential surface of the body formed by axially supported rotatably disuccinimidyl via a backup rubber and the lining layer made of a resin material, respectively together, to JikuSo a stem to the valve shaft hole formed in the diameter direction opposite position of the seat liner is a body-side lining layer, the pressure seal the Bentsubasa part of at least disuccinimidyl when rotated manipulate the stem to the body in the peripheral surface in the sealing structure of the butterfly valve which, the inner diameter of the sheet liner, and an inner diameter which is deformed to a diameter smaller than the outer diameter of disuccinimidyl an elastic force of the backup rubber at the time of valve opening, whereas, by pushing the disuccinimidyl in a valve closing set the inside diameter before deformation to the small-diameter by the elastic force of the backup rubber seal structure of the butterfly valve provided with a inner diameter before the deformed slightly larger diameter than or disuccinimidyl outside diameter (including the tolerance) the same diameter as disuccinimidyl OD it is.

[0010]

　Invention, the thickness of the backup rubber, by providing this width dimension of backup rubber and substantially the same size or slightly longer, a butterfly that was easily restored to the valve closed the inner diameter of the seat liner to the inner diameter of the before deformation according to claim 2 a seal structure of the valve.

[0011]

　The invention according to claim 3, when restoring to the valve closed the internal diameter of the sheet liner to the inner diameter before deformation, a bulging portion that bulges in the width direction in accordance with the backup rubber within the enlarged diameter, the body and the seat liner a seal structure of a butterfly valve so as to accommodate the gap portion provided therebetween.

[0012]

　The invention according to claim 4 is the sealing structure of a butterfly valve provided with a width of backup rubber substantially the same size as the Bentsubasa difference value of disuccinimidyl.

[0013]

　The invention according to claim 5, the lining layer is a seal structure of a butterfly valve is fluorine resin.

[0014]

　The invention according to claim 6 is provided with a tapered surface having a predetermined angle on both sides of Bentsubasa side tip of disuccinimidyl lining is disuccinimidyl side lining layer, to form a seal portion for pressing the seal into sheet liner between the tapered surfaces, the width of the seal portion is a sealing structure of a butterfly valve provided in substantially the same size as the core metal tip side of the width of disuccinimidyl.

Effect of the invention

[0015]

　According to the invention according to claim 1, the inner diameter of the sheet liner, restored to the inner diameter of the deformed diameter smaller than the outer diameter of disuccinimidyl an elastic force of the backup rubber at the time of valve opening, and pressed disuccinimidyl in a valve closing becomes the inner diameter before deformation to the small-diameter by the elastic force of the backup rubber on, by provided slightly larger diameter than the undeformed inner diameter (including tolerances) the same diameter as disuccinimidyl outer diameter or disuccinimidyl outer diameter, increase in operating torque without the need for a force to compress the resin lining layer can be prevented at the time of the valve closing operation. Moreover, if you increase the thickness also of the resin lining layer, this since the lining layer can be manipulated valve closed seal state without applying a force to compress, and easily open operation at a constant low operating torque.

[0016]

　According to the invention according to claim 2, the thickness of the backup rubber, by providing the width substantially the same size or slightly longer, deformation room for the radial direction becomes large, smoothly with the backup ring to open and close the valve reduced in diameter and enlarged, since the inner diameter of the seat liner is easily restored to the inside diameter before deformation can be prevented an increase in the operating torque.

[0017]

　According to the invention according to claim 3, by accommodating the bulging portion of the backup rubber which is enlarged in the gap and exert an equal pressing sealing force can be maintained reasonable sealed state.

[0018]

　According to the invention according to claim 4, surely it is possible to prevent the valve seat leakage to ensure the seal of the valve closing of the seat liner and disuccinimidyl in a range in which a backup rubber, disuccinimidyl is rotated until it is completely closed state even if not, it exhibits high sealability to absorb the error.

[0019]

　According to the invention according to claim 5, while improving chemical resistance and heat resistance by the lining layer and the fluororesin can be kept low operating torque at the time of valve closing operation, due to the sealing of disuccinimidyl of the lining layer suppressing the wear and deterioration can be improved durability.

[0020]

　According to the invention according to claim 6, to transmit a substantially evenly pressing force to disuccinimidyl lining is the sealing surface of the seat liner from the metal core at the time of valve closing seal, and excellent torque of the uniform surface pressure sealing force reliably prevent the valve seat leakage by increasing the seal of the Nagato valve blade portion and the body in the peripheral surface.

Brief description of the drawings

[0021]

FIG. 1 is a cutaway perspective view of a portion of the butterfly valve.
It is a central longitudinal sectional view of the butterfly valve of FIG. 2 FIG.
3 is a central lateral enlarged sectional view of the butterfly valve of FIG.
It is [4] a central longitudinal sectional view of the butterfly valve of FIG.
FIG. 5 is an enlarged cross-sectional view of FIG. 4.
6 is a fragmentary sectional view showing a mounting state of the seat liner in the central lateral enlarged sectional view of FIG.
It is disuccinimidyl in [7] FIG. 3 is a sectional view showing a state in which rotation.
8 is a partially enlarged sectional view showing the vicinity Bentsubasa of disuccinimidyl.
9 is a sectional view showing a sheet liner.
FIG. 10 is a central cross-sectional view showing a comparative example of the butterfly valve.
[FIG. 11] (a) is a perspective view showing the sheet liner. (B) is a longitudinal sectional view of the sheet liner.
[FIG. 12] (a) is a perspective view showing a disuccinimidyl. (B) is a longitudinal sectional view of disuccinimidyl.
13 is a sectional view showing a state of being deformed sheet liner.
An A-A sectional view of FIG 14 FIG 13.
[FIG. 15] (a) is a perspective view of the seat liner fitted with disuccinimidyl. (B) is a longitudinal sectional view of a sheet liner fitted with disuccinimidyl.
[FIG. 16] (a) is a perspective view of the seat liner fitted with stem. (B) is a longitudinal sectional view of a sheet liner fitted with stem.
17 is a side view showing a backup rubber.

Description of the code

[0022]

　1 valve body
　2 disuccinimidyl
　3 body
　4 backup rubber
　5 stem
　10 lining layer
　11 sheet liner
　12 disuccinimidyl lining
　12a inclined surface
　12b taper surface
　12c seal part
　13 Benjikuana
　20 Bentsubasa part
　φD1 disuccinimidyl outside diameter
　φd2 valve opens when the sheet liner an inner diameter of
　the inner diameter of the φd1 valve closing timing of the sheet liner
　width of L backup rubber
　S Bentsubasasachi
　width of Wa seal portion
　core metal tip side of the width of Wb disuccinimidyl

DESCRIPTION OF THE INVENTION

[0023]

　It will be described below in detail with reference to preferred embodiments and drawings thereof action of the seal structure of the butterfly valve of the present invention. 1 and 2 shows an example of a butterfly valve using a sealing structure of the present invention, in FIG. 3 shows a central horizontal enlarged cross-sectional view of the butterfly valve of FIG. It will be explained while showing the dimension example of the butterfly valve of nominal diameter 100A.

[0024]

　The butterfly valve (hereinafter, referred to as the valve body 1) FIG. 1 is, for example, used in semiconductor manufacturing plants and food related conduits and the like. Valve body 1 is disuccinimidyl 2, tubular body 3 of the backup rubber 4 has a stem 5 consisting of upper stem 5a and the lower stem 5 b, and the surface disuccinimidyl 2, disuccinimidyl 2 can rotate through a backup rubber 4 the inner peripheral side of the axially supported by the body 3, the sheet liner 11, the lining layer 10 made of disuccinimidyl lining 12 is provided.

[0025]

　As shown in FIG. 5, in the valve body 1, the stem 5 is JikuSo the valve shaft hole 13 provided in the diameter direction position facing the sheet liner 11, in the vicinity of the stem JikuSo unit 14, the rotation of the stem 5 the boss portion sealing surface 16 provided in the boss portion 15 and the body 3 side provided in disuccinimidyl 2 side vertical of disuccinimidyl 2 are sealed respectively during operation, the sealing of the so-called top-bottom seal (primary seal) is secured that. The inner peripheral side of the valve body 1, by, as shown in FIG. 3, the inner peripheral sealing surface 21 of Bentsubasa portion 20 and the body 3 of disuccinimidyl 2 are pressed against the seal in the circumferential direction, the Bentsubasa unit circumferential face seal of the 20 side is secured, the valve seat leakage is prevented.

[0026]

　1 to 5, disuccinimidyl 2 of the valve body 1 has a metal core 22, the core metal 22 is, for example, is formed in a disk shape stainless steel alloy as material. The core metal 22 is, for example, the aforementioned disuccinimidyl lining 12 of about 3mm thick is coated, the disuccinimidyl lining 12 is lining layer 10 of disuccinimidyl 2 surface or wetted surface. Disuccinimidyl lining 12 is made of a resin material, in this embodiment, provided by PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) Fluorine resins such as, are enabled exhibiting high corrosion resistance and heat resistance. Disuccinimidyl lining 12 through the through-hole 23 formed at an appropriate position of the core 22 is covered integrally with the outer periphery of the front and back surfaces of the core metal 22, leaving is prevented from metal core 22.

[0027]

　2, 4, as shown in FIG. 5, the top and bottom of disuccinimidyl 2, followed by lining the cylindrical portion 26 to be described later, upper and lower stem 5a, hexagonal square hole 24 for inserting 5b are stem It is formed as a hole. The stem bore 24, the upper and lower stem 5a, hexagonal prismatic portion formed as a connection portion 25 to the distal end of 5b is fitted respectively inserted, thereby, disuccinimidyl 2 upper and lower portions the stem 5a, 5b is JikuSo rotatably in the body 3 via the. Such a mounting structure, the upper and lower stem 5a, 5b is provided removably with respect disuccinimidyl 2 attached to the body 3. Disuccinimidyl 2 side of the stem hole 24, upper and lower stem 5a, 5b side of the connection portion 25 may be a polygonal shape other than the fitting possibly hexagonal one another, for example, width across flats or square shaft, such as spline connection, can be provided to the decomposition can be a variety of fitting structure and the upper and lower stem and disuccinimidyl.

[0028]

　4 and 5, the upper and lower stem 5a of disuccinimidyl lining 12 a vertical of disuccinimidyl 2, the insertion side of 5b, the lining cylindrical portion 26 is formed integrally with the disuccinimidyl lining 12. This lining cylindrical portion 26, the upper and lower stem 5a, the connection side of 5b are covered in the axial direction.

[0029]

　As shown in partially enlarged cross-sectional view of FIG. 8, on the both sides of disuccinimidyl lining 12, the inclined surface 12a is provided at the center of disuccinimidyl 2 toward the vicinity of the distal end side, Bentsubasa unit 20 continues to the inclined surface 12a tapered surface 12b on the side tip is provided at a predetermined angle. Between both sides of the tapered surface 12 b, the sealing portion 12c is formed in the vertical direction in the drawing, the seal portion 12c is enabled pressure sealed to the seat liner 11 is in the valve closed.

[0030]

　In this embodiment, the tapered surface 12b is provided by the slope of the inclination angle α from the inclined surface 12a, the inclined angle α is provided to 20 °. In this case, that the inclination angle β from the vertical surface side is provided so as to be 45 °, provided the width Wb of the distal end portion 22a of the width Wa and the metal core 22 of the seal portion 12c is in substantially the same width W It is. For example, if the width Wb of the distal end of the core 22 is 3 mm, the width Wa of the sealing portion is also set to 3 mm, the structure thus the disuccinimidyl distal end side and the width Wa = width Wb, the seal portion 12c seat the force received by the pressing of the liner 11, at the distal end portion 22a of the core 22 can be received with the same width as the sealing portion 12c, to prevent deterioration of the sealing surface pressure at this site, higher in the valve closing torque performance and seal seal structure is provided that combines and sex. The outer diameter φD1 of disuccinimidyl 2 in which said disuccinimidyl lining 12 is formed (see FIG. 3) is provided on the outer diameter of φ100mm in the present embodiment.

[0031]

　Figure 1, as shown in FIG. 2, a body 3 that disuccinimidyl 2 described above is mounted, the upper body 3a, consists of the lower body 3b, which are, for example, be formed by cast iron, such as ductile cast iron, another by bolts 27 It is detachably fixed. Upper and lower body 3a, JikuSoana 28 and 28 is provided in the 3b of the stem 5 JikuSogawa, the upper and lower stem 5a, 5b are respectively mounted on each of these JikuSoana 28. Following this JikuSoana 28, the holding side of disuccinimidyl 2 is provided enlarged-shaped mounting recess 29, the sealing bushing 30 through the mount recess 29, the sealing member 31, disc spring 32, the plate member 33 is furnished as a shaft sealing member 17, further bearing 34 is mounted.

[0032]

　Upper and lower body 3a, the peripheral face seal side 3b of Bentsubasa portion 20, the mounting groove 35 with a width of 10mm is formed in the shallower depth than the thickness of the backup rubber 4, the backup rubber 4 in the attachment groove 35 It is removably mounted. Upper and lower body 3a, on both sides of the 3b, bolt holes 36 can be secured to each other by a bolt 27 is provided.

[0033]

　Sheet liner 11 shown in FIG. 9, is attached while covering the body 3 in the thick inner peripheral side, for example, 3mm of the body 3, this sheet liner 11 becomes the lining layer 10 of the wetted surface side. Sheet liner 11 is made of a resin material, in this embodiment, as in the case of disuccinimidyl linings 12, are provided with a fluororesin such as PFA. Sheet liner 11 includes an annular portion 40 which is mounted in the body periphery, and a flange portion 41 projecting formed at both ends outside periphery of the annular portion 40, the upper and lower portions of the stem 5 of the annular portion 40 JikuSoto portion 42 is formed at the mounting position, the upper and lower stem 5a, 5b are provided to be respectively inserted into the JikuSoto portion 42.

[0034]

　The upper and lower stem 5a of the inner periphery of the annular portion 40, the shaft wear side of 5b and disuccinimidyl 2, the boss portion sealing surface 16 is projected formed in the axial deposition direction of the stem 5, the boss in the circumferential direction so as to sandwich a part sealing surface 16 seal portion 12c of Bentsubasa portion 20 arc-shaped the inner peripheral sealing surface 21 is formed in contact with the side.
　The inner circumferential sealing surface 21 is a flow path axis parallel to the direction a plane, also, the sealing portion 12c of disuccinimidyl 2 is part of a disk-shaped disuccinimidyl 2 and concentric spherical surface, the R form It is formed. Configured valve seat sealed by the and the seal portion 12c thereof in the circumferential sealing surface 21, a thin contact area linear both sites, since the so-called "line seal", the frictional force is small, the valve closing operation It contributes to suppress an increase in torque.

[0035]

　The inner circumferential sealing surface 21 in this embodiment, the inside diameter φd1 of eggplant Figure 6 the trajectory is provided so as to be 100 mm, the width L of the inner circumferential sealing surface 21 is provided respectively in 10mm in FIG. 6 (b) . On the back side of the inner circumferential sealing surface 21, a backup rubber 4 is disposed between the body 3, the inner peripheral sealing surface 21 of the sheet liner 11 is pressed in the direction of diameter by the backup rubber 4.

[0036]

　Two right and left backup rubber 4,4 shown in FIG. 3, for example by fluorine rubber is formed in the width and length dimensions which can be mounted to the mounting groove 35, in FIG. 2, the body 3 so as to sandwich the sealing bush 30 each of the left and right side is disposed. 7, the backup rubber 4 is disposed in the width of approximately the same size as the valve vane difference value S of disuccinimidyl 2, it is provided on substantially the same length as the width L of the inner circumferential sealing surface 21 of Bentsubasa seal side. In FIG. 6 (b), the thickness T of the backup rubber 4 is provided in the same dimension as the width L, the width L and thickness T in this embodiment is provided about 10 mm. Here, Bentsubasasachi S, due disuccinimidyl 2 shows a limit value of the slope of the valve closing sealable Bentsubasa portion 20, from the end face of the body 3 to Bentsubasa section 20 distal of the end side length S1 If, it is determined by the difference between the length S2 of the end surface of the body 3 to Bentsubasa section 20 distal of the other end.

[0037]

　The thickness T of the backup rubber 4, by being set to the same dimension as the width L, as described above, for a given compression rate, suitable squeeze is ensured. If, in the case where the thickness T is thin, change the width of the crushing rate increases due to variations in the size, operation torque is suddenly rise of the valve is closed, or fear of the sealing deterioration is high.

[0038]

　On the other hand, if the thickness T is too thick, the maximum outer diameter and the minimum outer diameter of the body 3 must be set to a deep dimension the mounting groove 35 under conditions that are more limited than the size of the pipe, the body pressure resistance It can not be secured minimum thickness for satisfying fear there. Further, if too thick, the influence of thermal expansion is increased, there is a possibility that operating torque of the valve closing is suddenly increased.
　Accordingly, the thickness T of the backup rubber may set within the range of 0.9L ≦ T ≦ 1.1L, preferably set to T = L or T ≦ 1.1 L.

[0039]

　Thus, the thickness T of the backup rubber 4, the width L of the backup rubber 4 provided dimensions substantially the same size or slightly longer, than the backup rubber 4 of the flat shape as in the prior art, a narrow backup width by using the rubber 4, the enlarged diameter becomes easy, that tends to restore the valve closed the internal diameter of the seat liner 11 to the inner diameter of the front the deformation, it is possible to prevent the increase in the operating torque.

[0040]

　The inner peripheral dimension x of the backup rubber 4 shown in FIG. 17 is formed in an arc length y and approximately equal sizes corresponding to the median diameter of the mounting groove 35 shown in FIG. End 4a of the backup rubber 4 is cut obliquely so as to be in close contact the entire surface of the outer peripheral surface of the sealing bushing 30. These arrangements backup rubber 4 which is attached to the attachment groove 35 without being deflected locally, so as to uniformly press the rear surface of the inner circumferential sealing surface 21 of the sheet liner 11.

[0041]

　Here, to illustrate the characteristics of the sealing arrangement of the present invention will be described in three states.
　As shown in FIG. 6 (a), if, when attaching the sheet liner 11 to the body 3 in a state of not mounting a backup rubber 4, the disuccinimidyl 2, i.e. in the formation state of the seat liner 11, the inner peripheral seal of the sheet liner 11 inner diameter φd1 of surface 21 is set to φ100mm of the same diameter as the outer diameter disuccinimidyl φD1.

[0042]

　At this time, in the figure, the distance HA to the inner circumferential sealing surface 21 from the bottom of the mounting groove 35, will be approximately 11.7 mm, the distance HB to the back of the inner circumferential sealing surface 21 from the bottom of the mounting groove 35, approximately become 8.7mm. Therefore, the thickness of the inner circumferential sealing surface 21 of the sheet liner is 3 mm. In this state, between the body 3 and the seat liner 11, a gap portion G'is provided. The gap G', at the valve closing, the bulging portion 37 to be described later in the inner periphery of the backup rubber 4 is pressed through the sheet liner 11 by disuccinimidyl 2, a space for accommodating at its neighboring position.

[0043]

　As shown in FIG. 6 (b), if, in the case of attaching the sheet liner 11 provided with a backup rubber 4 without mounting the disuccinimidyl 2 to the body 3 by the elastic force of the backup rubber 4 sheets liner 11 is condensed the diameter of deformation, the inner diameter of the inner peripheral sealing surface 21 that, that is, the seal portion 12c of the so-called disuccinimidyl 2 inner diameter φd2 of middle and high portion 45 to press seal is reduced in diameter from φ100mm to φ97.4. At this time, the distance HA1 of to the inner peripheral sealing surface 21 from the bottom surface of the mounting groove 35, but changes to 13mm from 11.7mm, wall thickness 3mm in inner peripheral sealing surface 21 of the sheet liner 11 is maintained.

[0044]

　Incidentally, when worn backup rubber 4 to the body 3, since the shallower the depth of the mounting groove 35 than the thickness T of the backup rubber 4 as described above, the inner peripheral side backup rubber 4 on the back of the inner peripheral sealing surface 21 of the sheet liner 11 in the projecting state in contact, gap G is provided between the sheet liner 11 and the body 3. That is, the gap G is for relative gap G'described above, the sheet liner 11 that is reduced in diameter was added a space for restoring the state of FIG. 6 (a).

[0045]

　3, the sheet liner 11 in the case of valve body 1 fitted with a disuccinimidyl 2 to the body 3 having a sheet liner 11 via a backup rubber 4, the valve opening time and valve closing in accordance with the rotation state of disuccinimidyl 2 inner diameter is different. At the time of valve opening, that is deformed in diameter direction by the elastic force of the backup rubber 4, the inner diameter of the middle and high portion 45 of the sheet liner 11, as shown in FIG. 6 is deformed to a diameter smaller than that described above disuccinimidyl outer diameter φD1 ( the inner diameter φ97.4mm of state of b). On the other hand, in the valve closed as shown in FIG. 3, by disuccinimidyl 2 presses the sheet liner 11 against the elastic force of the backup rubber 4, the inner diameter of the middle-high portions 45 of the sheet liner 11, the pressing of disuccinimidyl restored to the inside diameter prior to deformation, the inner diameter φd1 before this deformation will φ100mm state same as disuccinimidyl outer diameter φD1 of the same diameter as in FIG. 6 (a). At that time, the distance HA is approximately 11.7mm of to the inner peripheral sealing surface 21, the distance HB to the back of the inner peripheral sealing surface 21 from the mounting groove 35 bottom is approximately 8.7mm from the bottom of the mounting groove 35. Therefore, the thickness 3mm for the inner circumferential sealing surface 21 of the sheet liner 11 is maintained.

[0046]

　State Thus, in the valve closing disuccinimidyl 2 presses the sheet liner 11, when performing a valve seat seal, medium and high portions 45 (the inner peripheral seal surface 21) of the sheet liner 11 is not attached to the backup rubber 4 , i.e., merely returns to the dimensions of the formation of the sheet liner 11, there is no be compressed, good inner circumferential sealing surface 21 does not remain permanently strain is maintained in the sheet liner 11, a high valve seat seal it can be maintained over a sex-term.

[0047]

　Moreover, the torque required at the time of valve closing operation, to yield only by a force to elastically deform the backup rubber 4 in the diameter expanding direction, the operation torque is greatly reduced, so as to maintain the this reduced operating torque-term can.
　Then, these features without having to depend on the thickness of the sheet liner 11, for example, the thickness or thicker to about 4mm and, if large butterfly valve aperture exceeding nominal diameter 125A, within 5mm wall thickness high valve seat sealing property even when set, can be maintained low torque resistance.

[0048]

　In the peripheral face seal site by the inner circumferential sealing surface 21 of Bentsubasa portion 20 and the body 3 of disuccinimidyl 2 described above, in FIG. 7, when rotating the disuccinimidyl 2 from the closed state to the valve opening side, the disuccinimidyl 2 the valve within the rotating wings difference values ​​S (ranges provided convex portion 45), that the backup rubber 4 are formed to the same width as the inner peripheral seal surface 21 thereof as described above, the backup rubber 4 elasticity high sealability is exhibited is ensured by. In the scope of this valve wing difference values ​​S, the case of the above and are prevented from similarly compression of the sheet liner 11 and sealing properties and operating torque resistance is ensured.

[0049]

　Even in the case at the time of any of the valve closing seal, when you want to restore to the valve closed the inner diameter of the seat liner 11 to the inner diameter of the previous deformation, bulging portion 37 that bulges in the width direction with backup rubber 4 in the enlarged diameter is, deformed to collapse the gap portion G'provided between the body 3 and the seat liner 11 is housed in the gap portion G'. Therefore, to demonstrate the uniform pressing sealing force over the circumferential direction, it can be maintained reasonable sealed state.

[0050]

　Here, a comparative example for comparison with the sealing structure of the butterfly valve of the present invention shown in FIG. 10. The sheet liner 50, in FIG. 10 (a), the tentatively, backup rubber 4, when attached to the body 3 in a state where disuccinimidyl 2 is not installed, up to the back of the inner circumferential sealing surface 51 from the bottom of the mounting groove 35 distance HC becomes 10 mm, the inner diameter φdA1 of the inner circumferential sealing surface 51 is provided in a shape such that φ97.4mm. Thus, even as a backup rubber 4 having a thickness of 10mm the mounting groove 35 is mounted, it is never exerted diameter direction of the force from the backup rubber 4.

[0051]

　In FIG. 10 (b), the sheet liner 50, when attached to the body 3 via the backup rubber 4 has a sheet liner 50 is reduced in diameter deformed by the elastic force of the backup rubber 4, the inner circumferential sealing surface 51 inner diameter is reduced in diameter of. Then, the disuccinimidyl 2 is attached to the body 3, at the time of valve opening, the inner diameter φdA2 of the inner circumferential sealing surface 51 is a reduced diameter than Fai97.4Mm, in the valve closed, the disuccinimidyl outside diameter by the pressing of disuccinimidyl 2 It is enlarged to the size of φ100mm of φD1.

[0052]

　In this way, when the inner diameter φdA1 before deformation by disuccinimidyl 2 small sheet liner 50 than disuccinimidyl outer diameter φD1, in addition to the pressing deformation of backup rubber 4 when the valve closed state by rotating the disuccinimidyl 2, to compress the sheet liner 50, ie, a force for by subtracting the thickness of the sheet liner 50 is elastically deformed is additionally required. Moreover, the force to be compressed as the sheet liner 50 is thicker increases, in proportion to the thickness and operating torque of the seat liner 50 also increases. However, since the operating torque has acceptable limits, it is difficult to set the thickness of a certain size or more of the sheet liner 50. On the other hand, if the thickness of the sheet liner 50, it becomes difficult to satisfy the chemical resistance and heat resistance required for penetration resistance over performance is reduced.

[0053]

　Incidentally, the butterfly valve nominal diameter 100A of the present embodiment, were actually measured maximum torque at the time of valve closing operation in roses fly valves of the same nominal size corresponding to FIG. 10, the butterfly valve of the present embodiment, corresponding to FIG. 10 to the butterfly valve of the same nominal size to be, it was confirmed that can achieve torque reduction of about 23%.

[0054]

　Next, in a shaft seal sealing part of the stem 5 of the sheet liner 50, the outer peripheral front end outer peripheral tapered surface 60 of each shaft sweeping portion 42 as shown in FIG. 9 (b) is provided at an appropriate angle, the outer periphery the tapered surface 60 is formed on JikuSoto portion 42 wedge-shaped, base portion 64 of the JikuSoto portion 42 is provided in wall thickness than the outer peripheral tapered surface 60. Further, the height of the JikuSoto portion 42 is provided relatively short. By such a shape, when an external force is applied from the outer circumferential direction on the outer peripheral tapered surface 60, JikuSoto by only the outer peripheral tapered surface 60 around is deformed, the deformation near the base of JikuSoto portion 42 is prevented its roundness is ensured without the valve shaft hole 13 is a stem insertion hole formed in the inner peripheral parts 42 are deformed.

[0055]

　The inner periphery of each shaft sweeping portion 42, an annular projecting seal portion 61 projecting from the inner peripheral side is provided, the protruding sealing portion 61 is provided so as to be pressed against the seal on the outer circumference of the lining cylindrical portion 26 ing. This increases the sealing force around the protruding sealing portion 61, the leakage between the JikuSoto portion 42 and the lining cylindrical portion 26 is prevented.

[0056]

　The JikuSoto portion 42 proximal the outer peripheral side of, and is formed so as annular groove 62 is dented, JikuSoto unit 42 through the annular groove 62, is formed so as to protrude than the annular part 40 that. By being provided with the annular groove portion 62, even when the upper and lower stem 5a by applying a force to the seat liner. 11, 5 b the annular portion 40 and the flange portion 41 in the mounting direction of deformed into a substantially elliptical shape, JikuSoto deformation can be prevented part 42 becomes less susceptible to its effects.

[0057]

　4 and 5, the sealing bushing 30 is an axial seal member 17 described above, the sealing member 31, disc spring 32, the upper and lower body 3a to the plate member 33 is covered with the sheet liner 11 described above, each mounting recesses 3b is mounted in the 29, upper and lower stem 5a its inner periphery, 5b are positioned and held in a state of being inserted respectively. Bearings 34, upper and lower body 3a, in centrifugal position than the mounting recess 29 of 3b, upper and lower stem 5a, respectively provided to be interposed from the annular groove 62 side between 5b and JikuSoana 28. This bearing 34, the upper and lower stem 5a, rotation of 5b becomes smooth.

[0058]

　Disc spring 32, for example, by a spring steel which has been subjected to surface treatment provided on the outer diameter can be attached to the attachment recess 29 is disposed on the distal side than the sealing bushing 30 of the mounting recess 29. Between the disc spring 32 and the sealing bush 30, for example, plate-shaped annular plate members 33 are provided by stainless steel, through the plate member 33, the upper surface side of the pressing force and ceiling bushing 30 by the disc springs 32 It is uniformly transmitted to, vertical sealing (primary sealing) the above-described functions.

[0059]

　Sealing bushing 30 is, for example, with a carbon-containing PTFE (polytetrafluoroethylene) Fluorine resins such as is formed in a substantially annular attachable to the mounting recess 29, is attached to the attachment recess 29 so as to be in direct contact with the seat liner 11. The inner peripheral lower side of the position facing the outer peripheral tapered surface 60 of the sealing bushing 30, the inner peripheral tapered surface 63 is formed, and these inner circumferential tapered surface 63 and the outer peripheral tapered surface 60, same inclination relative to the vertical plane provided on the angle θ is pressed against the seal by abutment of surface contact. In this embodiment, the inclination angle θ between these inner circumferential tapered surface 63 and the outer peripheral tapered surface 60 is set to 20 °, when the pressing force is applied to the sealing bush 30 by the disc spring 32, these inner circumferential tapered pressing force by the component force in the direction of the stem diameter is generated by the wedge effect of the surface 63 and the outer peripheral tapered surface 60, the JikuSoto portion 42 in the pressing force brought into close contact with the lining cylindrical portion 26, this lining cylindrical portion 26 shaft seal by adhesion to the stem 5 outer peripheral surface (secondary seal) to function. Further, it may be provided an annular protrusion (not shown) on the inner peripheral side of the lining cylindrical portion 26, in this case, it is possible to increase the surface pressure of the shaft seal.

[0060]

　Between the sealing bushing 30 inner peripheral upper side of the lining cylindrical portion 26, the sealing member 31 is attached. Seal member 31 includes a metallic coil spring 65 formed by a corrosion resistant metal, consists of an annular cover member 66. which is formed by a fluororesin, mounting an annular coil spring 65 is formed in the cover member 66 grooves 67 is integrated fitted are in to. With this configuration, the sealing member 31, while the low elasticity of fluororesin is compensated by the elastic force of the coil spring 65, provided to be exhibited elastic sealing force in a radial direction by the elastic force of the coil spring 65 at the time of low pressure, the high pressure during each high sealing forces exerted by the elastic force of the fluid pressure and the coil spring 65.

[0061]

　The seal member 31, while in close contact with the inner peripheral tapered surface 63 of the sealing bush 30 on the outer peripheral tapered surface 60 of the JikuSoto section 42, the inner circumferential side lining the cylindrical portion 26 is brought into close contact with the stem 5 outer peripheral surface and the shaft seal ( tertiary seal) functions, while ensuring the chemical resistance and ultra-high temperature and ultra-low temperature resistance, the upper and lower stem 5a, the dynamic sealing property at the time of rotation of 5b is ensured. In order to ensure the location of the tertiary seal between the seal member 31 and the lining cylindrical portion 26, should the length of the lining cylindrical part 26 has reached up to this position, whereby the length of the line training cylindrical portion 26 It is to determine.

[0062]

　Sealing member 31 in this embodiment, the opening 31a is disposed outwardly of disuccinimidyl 2. Thus, any chance, the aforementioned primary seal, even as the fluid decreases the performance of the secondary seal has reached the sealing member 31, the coil spring 65 of the sealing member 31 can maintain a tertiary sealing function without wetted. Such an arrangement direction of the seal member 31 is particularly effective when handling the liquid is likely to corrode the metal.

[0063]

　As shown in FIG. 5, between the JikuSoto portion 42 of the sealing bush 30 and the seat liner 11, first gap portion 71, second gap portion 72 is formed. These first gap section 71, by providing the second gap portion 72, when the strong clamping force of the body 3 in order to increase the axial sealing force at the time of installation of the disuccinimidyl 2 to the body 3, from disuccinimidyl lining 12 side so that the escape meat lining layer 10 strong pressing force is deformed to join the sheet liner 11. Specifically, JikuSoto unit 42 first cavity portion 71 is deformed, lined cylindrical portion 26 becomes a space for releasing the meat of the sealing bushing 30, a sealing bushing 30 and the second cavity portion 72 is deformed, JikuSo the space for releasing the meat of the cylindrical portion 42. The first cavity portion 71, that is provided with the second gap portion 72, without the pressing force between the sealing part is increased more than necessary, high sealing properties while being suppressed operating torque is exerted.

[0064]

　Between the sheet liner 11 and ceiling bush 30, first gap portion 71, because the second gap portion 72 are respectively provided, escape meat deformed when a strong pressing force is applied by the disc spring 32, the resistance during rotation relaxation operating torque decreases. In addition, parts are prevented from that or damaged or deformation and fracture, high sealing performance in the shaft seal seal the site of both the upper and lower side is maintained.

[0065]

　As mentioned above, the inner diameter of the valve seal structure of the main body 1 is deformed to a smaller diameter than disuccinimidyl outer diameter φD1 the inner diameter of the seat liner 11 by the elastic force of the backup rubber 4 at the time of valve opening, valve closing of the sheet liner 11 φd1 is the inner diameter of the prior to deformation in diameter at the elastic force of the backup rubber 4, this deformation prior to the inner diameter φd1 is provided to have a diameter slightly larger than that disuccinimidyl outside diameter (including the tolerance) the same diameter as the φD1 or disuccinimidyl outer diameter φD1 by that, since no force to compress the sheet liner 11 from disuccinimidyl 2 the outer periphery of the sealing portion during the valve closing seal is applied, it is possible to prevent the increase in the operating torque while ensuring high sealability. Moreover, when increasing the thickness of the resin lining layer 10 also, because this lining layer 10 can be manipulated valve closed sealed state without applying a force to compress, and easily open operation at a constant low operating torque.

[0066]

　In this case, since the lining layer 10 is provided with a fluororesin, kept low operating torque at the time of valve closing operation while improving chemical resistance and heat resistance, while suppressing wear and deterioration during the sealing of disuccinimidyl 2 possible to improve the durability.

[0067]

　It should be noted that, in the present embodiment, the inner diameter φd1 of the inner circumferential sealing surface 21 of the sheet liner 11 and the outer diameter disuccinimidyl φD1 is set to φ100mm of the same diameter, processing tolerance of each of about ± 0.1mm in each of the parts there is.
　Therefore,
with respect to the outer diameter φD1 of-disuccinimidyl 2 φ99.9mm, the inner circumferential inner diameter φd1 of sealing surface 21 φ100.1mm of sheet liner 11
outer diameter φD1 of-disuccinimidyl 2 Whereas φ100.1mm, of sheet liner 11 inner diameter φd1 of the inner circumferential sealing surface 21 φ99.9mm
like, inner diameter φd1 of the inner circumferential sealing surface 21 of the sheet liner 11, sheet liner 11 is also substantially the same diameter of the case and the outer diameter φD1 of disuccinimidyl 2 at the time of the valve closing seal there is a structure is not to be compression seal, are included in the present invention.
　The outer diameter fD1 of disuccinimidyl 2 to 100 mm, so that the inner diameter of the inner circumferential sealing surface 21 is φ102mm sheet liner 11, the inside diameter φd1 of the inner circumferential sealing surface 21 of the sheet liner 11, the outer diameter of disuccinimidyl 2 fD1 is about 2% larger diameter than the seat liner 11 during a somewhat larger diameter of the case even valve closing seal has a structure is not to be compression seal, it is included in the present invention.

[0068]

　If the value at which the inside diameter φd1 of the sheet liner 11 is larger than the outside diameter φD1 of disuccinimidyl 2 exceeds 2%, a change in diameter before and after the sheet liner 11 is deformed to a small diameter by the elastic force of the backup rubber 4 since the increase, there is a fear be affected durability.
　Accordingly, the inside diameter φd1 before the sheet liner 11 is deformed to a small diameter by the elastic force of the backup rubber 4, from the viewpoint of ensuring the durability of the sealing property and sheet liner 11 with disuccinimidyl 2, substantially the same diameter as disuccinimidyl outer diameter φD1 It is preferred. The undeformed inner diameter φd1 of the sheet liner 11 of the present embodiment, for disuccinimidyl outer diameter fD1, may be set to 99.9% to 102%, more preferably, it is set to 100% 102% good.

[0069]

　Next, a method for manufacturing a valve body 1 described above.
　Valve body 1 described above can be formed by passing through a deforming step, centering step, the cylindrical portion inserting step, the stem connecting step, body integration step, the stem positioning step.
　11 shows a sealable preceding sheet liner 11 disuccinimidyl 2 outer circumferential side shown in FIG. 12, first, so as to deform the sheet liner 11 in the deforming step.

[0070]

　13, 14 shows a state in which the sheet liner 11 is deformed by an external force, in which were transformed into oval by applying an external force in a normal temperature. Before adding the external force, as shown in FIG. 13, rotates the disuccinimidyl 2 to the fully open state, subsequently, the outer periphery of the sheet liner 11 when external force is applied parallel to the flange portion 41 of the sheet liner 11, and, pressed by sandwiching between JikuSoto 42 base part 90 from the axis and the direction perpendicular to the back of the inner peripheral sealing surface 21 of the sheet liner 11 of the vise of, the long side is the direction of the JikuSoto 42 to deform to become such an ellipse with.

[0071]

　In this case, so that the long side R1 of the inner peripheral seal surface 21 of the sheet liner 11 which is deformed into an elliptic shape is pressed from outside to be longer than the full length R2, including lining the cylindrical portion 26 of disuccinimidyl 2.
　The pressing operation, may be carried out directly by the operator's hand, such as vice and vice (vice), preferably using an apparatus capable of holding a sheet liner elliptically. By thus holding the sheet liner 11 to an elliptical shape, it is easy centering combined work with disuccinimidyl 2 during centering step described below.

[0072]

　The size of the force applied to the seat liner 11 during the pressing, a state capable of maintaining elasticity of the sheet liner 11, in particular, to a state close to a perfect circle, or perfect circle from the elliptical by the release of the pressing, as described later It can be restored to become a force, to be the so-called elastically deformable range. Sheet liner 11 does not need to be completely true circle prior to assembly, and may be accustomed to a true circle after providing the valve body 1 is incorporated into the body 3.

[0073]

　As described above, the shorter form a JikuSoto section 42, so as to base 64 in JikuSoto section 42 by an outer peripheral tapered surface 60 in this JikuSoto section 42 provided with become more thick, further, annular groove 62 by the are provided, the deformation of Benjikuana 13 is prevented when sandwiching the stem at the base part 90, the roundness is maintained.

[0074]

　Subsequently, in the centering step, the inner periphery of the sheet liner 11 in a state of deforming is charged with disuccinimidyl 2. At this time, and the axis of the disuccinimidyl 2 side of the lining the cylindrical portion 26, in parallel to the axis of the JikuSoto portion 42 of the sheet liner 11 side, and, and the open side of the disuccinimidyl 2 and the top and bottom of each valve shaft hole 13 while in the distance holding the position of disuccinimidyl 2 to be the same, to move the disuccinimidyl 2 to match core and the axis of the lining the cylindrical portion 26 and the JikuSoto section 42 to the inner periphery of the sheet liner 11. At this time insert a non cylindrical jig shown previously valve shaft hole 13, it may be reinforced from the inner periphery of the valve shaft hole 13 by the jig. The length of the jig shall shorter than upper and lower stem 5a, the 5b.

[0075]

　After the core alignment process, in the cylindrical portion insertion step, to weaken gradually the external force to the sheet liner 11. Insert Thus, the sheet liner 11 is automatically restored from the elliptical shape into a perfect circle shape by its elastic force, 15, the JikuSoto portion 42 circumferential lining the cylindrical portion 26 of disuccinimidyl 2 constitutes a stem hole while being that disuccinimidyl 2 is attached to the seat liner 11, the cylindrical portion insertion step is completed. Thus, lining the cylindrical portion 26 of disuccinimidyl 2, while being supported by the JikuSoto portion 42 of the seat liner 11, disuccinimidyl 2 and sheet liner 11 and is unitized upper and lower stem 5a, and 5b in a state connectable It is. Incidentally, may be provided is a gap between the vertical side and the sheet liner 11 of disuccinimidyl 2, this gap are combined shaft seal member 17 shown in FIG. 5 in the body unifying step described later, thereby , it is composed of the shaft seal portion of the disuccinimidyl 2 heaven and earth side.

[0076]

　In the stem connecting step, in FIG. 16, the upper and lower stem 5a to the stem hole 24, and 5b the front end side of the connecting portion 25 is gradually inserted while aligning the shaft center, to connect these upper and lower stem 5a and 5b to disuccinimidyl 2 . Upper and lower stem 5a, the 5b, the tapered surface portion 91 is provided between the boundary portion between the connecting portion 25 and the cylindrical portion, the upper and lower stem 5a by the tapered surface portion 91, the lining cylinder when inserted 5b into disuccinimidyl 2 so as to prevent damage to the section 26.
　These upper and lower stem 5a, at the time of insertion of the 5 b, but the stem hole 24 in accordance with this insert there is a possibility that air is accumulated, that escape the air upper and lower stem 5a, 5b and from between the lining cylindrical portion 26 it can.

[0077]

　In the body integration step, the upper and lower body 3a equipped with the shaft seal member 17, the upper and lower stem 5a at 3b, 5 b in a state sandwiching the sheet liner 11 having a built-in disuccinimidyl 2 connected, the upper and lower stem 5a, connect the 5b to disuccinimidyl 2 this upper and lower stem 5a, in a state where the disuccinimidyl 2 rotatable operation in 5b, to integrate the upper and lower body 3a, the 3b.

[0078]

　In detail this, first of all, to mount the shaft seal member 17 to the mounting recess 29 of the pre-upper body 3a. At that time, from the back side of the mounting recess 29 fitted with bearings 34, disc spring 32, the seal member 31, the plate member 33, arranged in the order of the sealing bush 30.
　Thus the upper body 3a equipped with the shaft seal member 17, to incorporate the upper and lower stem 5a, the sheet liner 11 having a built-in disuccinimidyl 2 connected to 5b. Thus, the upper half of the sheet liner 11 is incorporated in the upper body 3a.

[0079]

　On the other hand, with respect to the lower body 3b, as in the upper body 3a, previously mounting the shaft seal member 17 in advance mounting recess 29.
　In this state, the lower half side of the sheet liner 11 built into the upper body 3a so as to incorporate the lower body 3b, these upper body 3a and the lower body 3b, a state sandwiched a sheet liner 11.

[0080]

　In this state, the screwed bolt 27 upper and lower body 3a, 3b are fixed to each other in the upper and lower body 3a, bolt hole 36 of 3b, as shown in Figure 2. Thus, the upper and lower body 3a, 3b are disc springs 32 are clamped screwing direction compression by the pressing force of the disc spring 32 described above acts on the sealing bush 30, the circumferential side of disuccinimidyl second sheet liner 11 a circumferential seal is a primary seal with disuccinimidyl 2, a secondary seal to the inner periphery of the JikuSoto portion 42 is the lining cylindrical portion 26 in close contact with the lining cylindrical portion 26 the outer periphery is in close contact seal the stem 5 peripheral surface axis as and the seal, and a shaft seal is a tertiary sealing by the seal member 31, upper and lower stem 5a, and functional composite in the axial deposition site of the 5 b, the sealing function of the valve blade side as described above together with this shaft sealing sealing function synergistically by being exerted it can be increased ensuring the sealing performance at disuccinimidyl 2 entire circumference after assembly.

[0081]

　In the stem positioning step, upper stem 5a, and 5b the lower stem, each of the upper body 3a, to prevent the jumping out of these by positioning fixed in a rotatable state in the lower body 3b.

[0082]

　In FIG. 2, for the upper stem 5a, O-ring 80 for dust-proof, through the thrust washer 81, C-type retaining ring 82 is mounted. In this case, in a state where the insertion of the upper stem 5a in disuccinimidyl 2, O-ring 80 to the position of the upper outer periphery of the upper stem 5a, the thrust washer 81 is mounted, the C-type retaining ring 82 upper stem 5a from the top thereof to engage in. In this state, through the upper side of the thrust washer 81 of the C-type retaining ring 82 to place the ground plate 83 for the lid, with screws (not shown) this ground plate 83 is fixed from the upper side of the valve body 1. By assembling this manner the upper body 3a side, it can be provided with pop-out preventing structure of upper stem 5a by a C-type retaining ring 82 and the ground plate 83 via a thrust washer 81.

[0083]

　For lower stem 5b, O-ring 80, thrust washer 81 is mounted through the end plate 84 for the lid. In this case, the O-ring 80 fitted on the outer periphery of the thrust washer 81, and interior to JikuSoana 28 forming the thrust washer 81 to the lower body 3b, it is disposed opposite to the valve outer side end face of the lower stem 5b. In this state, so as to block the JikuSoana 28 in the end plate 84, it is fixed from the lower side of the valve body 1 this end plate 84 in the fixing bolt 85. This JikuSo of the lower stem 5b side is completed.

[0084]

　Moreover, when disassembling the valve body 1 may be carried out by procedures for the reverse of the assembly described above. In this case, the upper and lower body 3a, the after removal from the sheet liner 11 may 3b, may be decomposed sheet liner 11 in the following manner.

[0085]

　In the upper and lower portions of the sheet liner 11, remove and from the sheet liner 11 to extract the sealing bush 30 gradually. Up and down the stem 5a, if you remove the 5b, these up and down the stem 5a, 5b so as withdrawn sequentially from the valve shaft hole 13 gradually of disuccinimidyl 2 while gripping each.

[0086]

　Up and down the stem 5a, after 5b withdrawal of, rotate the disuccinimidyl 2 on the state of the fully open position as shown in FIG. 13, the flow path outer periphery of the sheet liner 11 in parallel to the flange portion 41, and, JikuSoto 42 pressing the axis of the from the orthogonal direction, this JikuSoto section 42 direction deforms the ellipse such that the long side. Until the long side of the sheet liner 11 which deforms the pressing elliptical exceeds the height of disuccinimidyl 2, parallel to the axis of the axial core and the lining cylindrical portion 26 of the JikuSoto portion 42, and disuccinimidyl 2 while of the height and the distance to the JikuSoto section 42 to each other to the same extent, gradually to remove the disuccinimidyl 2 from the sheet liner 11. It is possible to decompose in the manner described above.

[0087]

　As described above, an external force is applied at room temperature state to the sheet liner 11 in a state of being deformed into an elliptical shape, was charged with disuccinimidyl 2 with centering state the inner periphery of the sheet liner 11, the sheet liner 11 from the elliptical shape the disuccinimidyl 2 by inserting the lining cylindrical portion 26 to JikuSoto section 42 is attached to the sheet liner 11 is restored to a true circle, then, the upper and lower stem 5a to the stem hole 24 of disuccinimidyl 2, 5b of the connecting portion It connects these gradually inserts 25, upper and lower body 3a equipped with the shaft seal member 17, and produce the valve body 1 so as to integrate sandwich the sheet liner 11 with a built-disuccinimidyl 2 3b by there, while improving the sealing properties in the vicinity of the boss portion 15 of the seat ring 11, it can be assembled easily fitted with a disuccinimidyl 2 while preventing damage to the resin-coated portion of the sheet liner 11 and the stem 5. Moreover, for the disassembly work, and just as easy to be carried out in the case of the assembly.

[0088]

　In this case, the sheet liner 11 is deformed into an elliptical shape, by pressing from the outside to be longer than the full length R2 inner periphery of the long side R1 of the sealing surface 21 of disuccinimidyl 2 of the sheet liner 11, disuccinimidyl 2 while reliably prevent coming into contact with the sheet liner 11, to attach and detach the disuccinimidyl 2 to the sheet liner 11 to ensure the shaft seal sealing properties in the vicinity of the boss 15 parts.

Claim 1]

　And disuccinimidyl surface, to the inner peripheral surface of the body formed by axially supported rotatably disuccinimidyl via a backup rubber provided with lining layer made of a resin material, respectively, diametrically opposite position of the seat liner is body-side lining layer in the sealing structure of the butterfly valve stem was JikuSo to the valve shaft hole provided, for pressing the seal into the body inner peripheral surface of the Bentsubasa portion of at least disuccinimidyl when the rotational operation of the stem, the inner diameter of the sheet liner, during valve opening and said backup rubber elasticity at an inner diameter which is deformed to a diameter smaller than the outer diameter of the disuccinimidyl, whereas, in the valve closing deformed in diameter at the resilient force of said backup rubber with the disuccinimidyl presses set before the inner diameter, the sealing structure of the butterfly valve, characterized in that the inner diameter before the deformation which is provided slightly larger diameter than the disuccinimidyl including tolerance outer diameter and the same diameter or disuccinimidyl outer diameter.

[Claim 2]

　The thickness of the backup rubber, by providing the width of the backup rubber substantially the same size or slightly longer, according to claim 1, wherein the inner diameter of the seat liner in the valve closed and easily restored to the inner diameter of the front the deformation seal structure of the butterfly valve.

[Claim 3]

　When you restore the valve closed the inner diameter of the seat liner to the inner diameter of before the deformation, the bulging portion of the backup rubber bulges in the width direction with the enlarged, provided between the sheet liner and the body the seal structure of the butterfly valve according to claim 1 or 2 and adapted to receive the gap portion.

[Claim 4]

　The seal structure of the butterfly valve according to the width of said backup rubber to any one of claims 1 to 3 provided in the substantially same size as the Bentsubasa difference value of the disuccinimidyl.

[Claim 5]

　The lining layer, the sealing structure of the butterfly valve according to any one of claims 1 to 4, which is a fluororesin.

[6.]

　Provided a tapered surface having a predetermined angle on both sides of Bentsubasa side tip of disuccinimidyl lining is the disuccinimidyl side lining layer, to form a seal portion for pressing the seal into the seat liner between the tapered surfaces, the width of the seal portion the seal structure of the butterfly valve according to any one of claims 1 to 5 were provided substantially the same size as the core metal tip side of the width of the disuccinimidyl.