Lining-type butterfly valve and manufacturing method thereof

Abstract

Provided is a highly compact, lining-type butterfly valve having a vertically separable body structure and having excellent chemical resistance and heat resistance, wherein, when assembling the bodies, the bodies can be connected while securing strength against stress generated in the upper and lower bodies, and preventing deformation or cracking of the body as a whole near a stem housing portion. In at least one of an upper body 2a and a lower body 2b, a stem housing portion 13 protrudes from an outer peripheral side surface 12, and rib portions 20 extending from an intermediate position toward the outer peripheral side surface are provided on both sides near a joint portion of the upper body and / or the lower body. The height H of the rib portions gradually decreases from the stem housing portion side toward an end portion side of the body. When connecting the upper body and the lower body, the upper and lower bodies are able to withstand the stress in the vicinity of the stem housing portion when a force expanding the semi-circular upper and lower bodies is applied.

Description

Lining type butterfly valve and its manufacturing method

[0001] The present invention relates to a lining type butterfly valve, and more particularly to the structure of a wafer-type butterfly valve body in which a resin lining is applied to the valve disc and the inner peripheral surface of the valve body, and a method for manufacturing a lining type butterfly valve.

[0002] Known butterfly valves used in chemical plants where highly corrosive fluids flow, in food-related flow passages, etc., include wafer-type butterfly valves with a so-called lining structure, in which the metal core of the valve disc is resin-lined and a resin seat ring is attached to the inner circumferential surface of the valve body. In this type of lining-type butterfly valve, the valve body is generally divided into upper and lower halves in a roughly semicircular shape to accommodate an annular seat ring attached to the inner circumferential surface of the valve body. These upper and lower valve bodies are often joined together near their ends with fastening bolts, with the seat ring sandwiched between them and a pressing force applied from the outside.

[0003] In this case, fluororesin, which has excellent chemical and heat resistance, is usually used as the lining material. However, fluororesin has poor elasticity, making it difficult to ensure sealing, particularly near the seal area between the valve blades and the valve body, where pressure sealing is required when the valve is closed, making it prone to leaks. Therefore, in such butterfly valves, a rubber backup ring is sometimes attached to the back side of the seat ring, and the elastic repulsive force of this backup ring is often used to press the seat ring toward the valve body, compensating for the lack of elasticity on the valve blade side, etc. In this case, a sealing bushing member may be attached to the outer periphery of the stem to ensure sealing on the stem mounting side as well.

[0004] An example of this type of butterfly valve is disclosed in Patent Document 1. In this butterfly valve, backup rings are arranged in an arc shape between the valve body and the outer periphery of the seat ring, and bushing members for inserting the valve stem are attached around the upper and lower stem holes between the backup rings.

[0005] When assembling a butterfly valve with this structure, bushings and backup rings are typically placed in predetermined positions between the upper and lower valve bodies and the seat ring, and the valve disc with the stem attached is placed on the inner circumferential surface of the seat ring, and the upper and lower valve bodies are then pressed together in the connecting direction, sandwiching the backup ring between the upper and lower valve bodies and the seat ring, and the upper and lower valve bodies are assembled while the elastic force of the backup ring increases the sealing force of the seat ring against the valve disc, and in this state the upper and lower valve bodies are fastened together with bolts or the like at both ends to connect the upper and lower valve bodies.

[0006] Generally, wafer-type butterfly valves have bolt guides integrally formed with the valve body for bolt fastening to connect pipes, and some of these have rib-like protruding bolt guides near a cylindrical stem housing formed in the valve body that connect this stem housing to the adjacent outer periphery of the valve body. Examples of butterfly valves with rib-like bolt guides include the one disclosed in Patent Document 2, which has a roughly ear-shaped bolt guide, and the one disclosed in Patent Document 3, which has a roughly rectangular rib (bolt guide) as shown in Figure 7.

[0007] Japanese Patent Application Laid-Open No. 2012-219819 Japanese Patent Application Laid-Open No. 10-501603 Japanese Patent Application Laid-Open No. 2002-122245

[0008] When assembling the above-described lining-type butterfly valve, when a force is applied in the direction connecting the upper and lower valve bodies, the backup rings attached to the inner peripheries of these valve bodies generate a reaction force that resists the direction of crushing from the valve bodies in the radial direction. When the upper and lower valve bodies are initially connected, the upper and lower stem mounting sides of the valve disc abut the bushing member mounting sides of the seat ring. When a force is subsequently applied in the connecting direction, the force that attempts to crush the backup rings through the valve disc is gradually transmitted from the vicinity of the upper and lower stems toward the circumferential direction of the valve body. Accordingly, the repulsive force of the backup rings that opposes the crushing force increases from the vicinity of the stem housing portions of the upper and lower valve bodies toward both ends. Therefore, stress is generated in the approximately semicircular upper and lower valve bodies due to the force that tries to spread the ends apart.

[0009] In this case, the approximately semicircular upper and lower valve bodies are each joined (attached) to the stem housing portion, and because these attachment portions are on the fixed portion side relative to the end portions, the force applied to both end portions of the semicircular valve body is greatest near the stem housing portion (the bushing member mounting side), which is on the fixed portion side. As described above, the repulsive force of the backup ring gradually increases from near the stem housing portion of the semicircular valve body toward both end portions, and the stress generated in the valve body by this force gradually increases proportionally from both end portions of the valve body toward the stem housing portion, reaching a maximum near the stem housing portion. For this reason, in the case of a butterfly valve whose valve body is formed from an aluminum material, which has lower tensile strength and other strengths than iron-based materials, the area near the stem housing portion may be unable to withstand the concentrated stress, resulting in deformation or cracking centered around the stem housing portion.

[0010] In contrast to this, Patent Document 2 uses ear-shaped bolt guides, and Patent Document 3 uses approximately rectangular ribs to form rib-shaped bolt guides between the stem storage section of the valve body and the adjacent outer peripheral surface of the valve body, but these bolt guides are provided to guide the fixing bolts for connecting the piping, and are not intended to improve strength against stress caused by the reaction force of the backup ring.

[0011] Therefore, although these butterfly valves have locally improved strength near the ribs against stress during assembly, they are unable to sufficiently improve strength near the stem housing. This makes it difficult to reliably prevent deformation and cracking near the stem housing during assembly, and deformation and cracking are particularly likely to occur when the valve body is made of a low-strength material. Furthermore, when a portion of the bolt guide is formed into a constricted shape, as in the case of Patent Document 2, stress concentration is more likely to occur in this constricted area, making deformation and cracking even more likely.

[0012] On the other hand, if the rib-shaped bolt guide is unnecessarily enlarged in the outer diameter direction in order to improve strength, the butterfly valve as a whole will become larger, making it impossible to install in a narrow installation space, and increasing the amount of material used, leading to problems such as an increase in weight.

[0013] The present invention was developed to solve the above-mentioned problems, and its purpose is to provide a lining-type butterfly valve with an upper and lower split body structure that has excellent chemical resistance and heat resistance, and that has excellent compactness and can be connected while ensuring strength against stresses that occur in the upper and lower body parts during assembly, and preventing deformation and cracking of the entire body, especially around the stem housing part.

[0014] In order to achieve the above object, the invention of claim 1 is a lining type butterfly valve in which a seat liner is attached to the inner peripheral surface of a circular body formed by connecting a semicircular upper body and a semicircular lower body, and a cylindrical stem accommodating portion is formed on at least one of the upper body or the lower body so as to protrude from the outer peripheral side surface of the body, and ribs are provided on both sides of the joint of this stem accommodating portion with the upper body and / or the lower body, extending from a midpoint of the stem accommodating portion toward the outer peripheral side surface of the body, and when the height of each rib portion is defined as the difference in linear distance from the center of the disc to the top surface and from the center of the disc to the outer peripheral side surface of the body, the height of each rib portion is gradually reduced from the stem accommodating portion side toward the end side of the body, and this lining type butterfly valve is capable of responding to stress near the stem accommodating portion when a force is applied to spread the upper and lower semicircular bodies when the upper and lower bodies are connected.

[0015] The invention according to claim 2 is a lining type butterfly valve in which backup rubbers are attached to accommodation grooves formed on the inner surfaces of the upper and lower bodies, and a seat liner is attached to the inner surface of the body with the backup rubber interposed therebetween.

[0016] The invention of claim 3 is a lining type butterfly valve in which the boundary between the rib portion and the outer peripheral side surface of the body is formed to a position at least more than halfway from the stem accommodating portion to the end of the body in the upper body and / or lower body.

[0017] The invention according to claim 4 is a lining type butterfly valve in which the boundary between the rib portion and the outer peripheral side surface of the body is formed in a tangential direction of the outer peripheral side surface of the body.

[0018] The invention according to claim 5 is a lining type butterfly valve in which a bolt insertion hole for face-to-face connection is formed in the rib portion.

[0019] The invention of claim 6 is a lining type butterfly valve in which the disk has a first stem insertion hole on the top side for pivoting the upper stem, and the disk has a second stem insertion hole on the bottom side for pivoting the lower stem, the second stem insertion hole having a locking structure that allows the disk and lower stem to rotate integrally, and the disk is configured to be freely rotatable relative to the body through operation of the upper stem pivoted in the first stem insertion hole.

[0020] The invention of claim 7 is a method for manufacturing a lining-type butterfly valve in which both end connecting portions of a semicircular upper body having a seat liner attached to its inner periphery and a semicircular lower body having a seat liner attached to its inner periphery are connected by fastening members, a cylindrical stem accommodating portion is formed protruding from one or both of the upper and lower bodies, and a reinforcing rib portion is provided that extends from partway along the protruding direction of the stem accommodating portion toward the outer circumferential surface of one or both of the upper and lower bodies, and when the height of this rib portion is defined as the difference in linear distance from the center of the disc to the top surface and from the center of the disc to the outer circumferential side of the body, the height of each rib portion is gradually reduced from the stem accommodating portion side toward the end side of the body, and when the upper and lower bodies are connected, a pressing process in which both end connecting portions are abutted and pressed and a tightening process in which the fastening members are tightened are repeated, so that the method can respond to stress near the stem accommodating portion when a force is applied to spread the upper and lower semicircular bodies apart.

[0021] The invention of claim 8 is a manufacturing method of a lining type butterfly valve in which backup rubbers are attached to accommodation grooves formed on the inner surfaces of the upper and lower bodies, and a seat liner is attached to the inner surface of the body with the backup rubber interposed therebetween.

[0022] According to the invention of claim 1, a lined butterfly valve with an upper and lower split body structure having excellent chemical resistance and heat resistance can be provided. Ribs are provided on both sides of the cylindrical stem housing near the joint, extending from a midpoint of the stem housing toward the outer circumferential side of the body, and the height of these ribs gradually decreases from the stem housing side toward the end of the body. When a force is applied to spread the semicircular upper and lower bodies when connecting the upper and lower bodies, the ribs can accommodate the stress near the stem housing. Therefore, when the upper and lower bodies are connected, the stress gradually increases from both ends of the upper and lower bodies toward the stem housing, and reinforcement can be gradually provided toward the stem housing to accommodate this gradually increasing stress. By avoiding localized stress concentration, the strength of the entire body can be ensured, centering on the vicinity of the stem housing. Therefore, even when the body is made of aluminum or other materials with lower strength than iron-based materials, it is possible to easily and accurately connect the body and assemble the entire valve with high precision while preventing deformation or cracking of the entire body, especially around the stem housing. Moreover, by making the rib portion as small as possible, it is possible to maintain the overall compactness and reduce the weight by suppressing the increase in material.

[0023] According to the invention of claim 2, by providing backup rubber between the accommodation grooves of the upper and lower bodies and the seat liner, the elastic repulsive force of the backup rubber is used to press the seat liner toward the disc when the valve is closed, improving sealing performance mainly around the valve blade side and ensuring sealing performance around the stem mounting portion side. In this case, the upper and lower bodies can be connected while the elastic repulsive force of the backup rubber is applied approximately uniformly to the approximately annular seat liner while the elastic repulsive force of the backup rubber is uniformly transmitted to the approximately annular seat liner. After these connections are made, the peripheral sealing performance between the seat liner and the disc when the valve is closed is improved, reliably preventing fluid leakage. If the backup rubber is densely packed in the accommodation groove, there is no place for the backup rubber to escape when a crushing force is applied, and the elastic repulsive force becomes extremely large. However, according to the present invention, even if such elastic repulsive force is generated, stress concentration near the stem accommodation portion can be avoided, effectively reducing the occurrence of cracks in the body.

[0024] According to the invention of claim 3, the boundary between the rib portion and the outer peripheral side surface of the body is formed to a position that is at least halfway from the stem accommodating portion to the end of the body in the upper body and / or lower body, thereby reinforcing more than half of the distance from the stem accommodating portion to the end of the outer peripheral side surface of the semicircular upper body and / or lower body, which is particularly effective in preventing deformation and cracking of the body due to stresses that are more likely to occur near the stem accommodating portion.

[0025] According to the invention of claim 4, the boundary between the rib portion and the outer peripheral side surface of the body is formed in the tangential direction of the outer peripheral side surface of the body. Therefore, when stress is applied to the semicircular upper and lower bodies during assembly, there is no risk of this stress being concentrated in one part of the rib portion. Instead, the strength of the rib portion is increased from near the boundary to near the stem accommodating portion in proportion to the stress that gradually increases from both ends of the upper and lower bodies toward the stem accommodating portion, thereby absorbing the stress and reliably preventing deformation or cracking of the entire body, centered around the stem accommodating portion.

[0026] According to the invention of claim 5, the strength of the body can be significantly improved by utilizing the rib portion having bolt insertion holes for surface-to-surface connections to external piping, etc., without providing any additional parts to the body to reinforce its strength, thereby maintaining compactness and making it possible to suppress increases in the amount of material and weight that make up the body.

[0027] According to the invention of claim 6, the top and bottom sides of the disk have a first stem insertion hole for pivoting the upper stem, and the bottom side of the disk has a second stem insertion hole for pivoting the lower stem, and the second stem insertion hole has a locking structure that allows the disk and lower stem to rotate together, so that when the disk rotates relative to the body through operation of the upper stem pivoted in the first stem insertion hole, the upper stem, lower stem, and disk rotate together. As a result, when the upper stem is operated, the disk does not rotate because the lower stem is in a non-rotating state, and twisting or torsion of the lining layer covering the periphery of the lower stem is eliminated, preventing rupture of the lining layer and improving the durability of the lined butterfly valve.

[0028] According to the seventh aspect of the present invention, a lining type butterfly valve having an upper and lower split body structure with excellent chemical resistance and heat resistance can be provided. A semicircular upper body with a seat liner attached to its inner periphery and a semicircular lower body with a seat liner attached to its inner periphery are connected at their end connecting portions with fastening members, and a reinforcing rib portion is provided extending from midway in the protruding direction of a cylindrical stem accommodating portion formed on one or both of the upper and lower bodies toward the outer circumferential surface of one or both of the upper and lower bodies, with the height of this rib portion gradually decreasing from the stem accommodating portion side toward the end side of the body.When the upper and lower bodies are connected, the pressing process and the fastening member tightening process are repeated, so that when a force is applied to spread the semicircular upper and lower bodies apart, the stress near the stem accommodating portion can be accommodated.When the upper and lower bodies are connected, the upper and lower bodies can be connected to each other so as to accommodate the gradually increasing stress that gradually increases from both end sides of the upper and lower bodies toward the stem accommodating portion, and the bodies can be assembled while ensuring strength mainly near the stem accommodating portion without localized stress concentration. Therefore, even if the body is made of aluminum, which is weaker than iron-based materials, it is possible to prevent deformation or cracking of the entire body, especially the stem accommodating section, while simply and accurately connecting the body and assembling the entire valve with high precision.

[0029] According to the eighth aspect of the present invention, backup rubber is provided between the seat liner and the accommodation groove of the upper and lower bodies. The elastic repulsive force of the backup rubber is used to press the seat liner toward the disc when the valve is closed, improving sealing performance mainly around the valve blade side and ensuring sealing performance around the stem mounting portion side. In this case, the upper and lower bodies can be connected while the elastic repulsive force of the backup rubber is uniformly transmitted to the annular seat liner. After connection, the peripheral sealing performance between the seat liner and the disc when the valve is closed is improved, reliably preventing fluid leakage. If the backup rubber is densely packed in the accommodation groove, there is no place for the backup rubber to escape when a crushing force is applied, and the elastic repulsive force becomes extremely large. However, according to the present invention, even if such elastic repulsive force is generated, stress concentration near the stem accommodation portion can be avoided, thereby effectively reducing the occurrence of cracks in the body and integrating the body.

[0030] FIG. 1 is a half-section view showing an embodiment of a lining type butterfly valve of the present invention. FIG. 2 is a section view taken along line A-A in FIG. 1. FIG. 3 is a section view taken along line B-B in FIG. 1. FIG. 4 is a section view taken along line C-C in FIG. 1. FIG. 5 is a partially cutaway perspective view of FIG. 1. FIG. 6 is a schematic diagram showing an assembly process of a lining type butterfly valve. FIG. 7 is a front view showing another embodiment of a lining type butterfly valve of the present invention. FIG. 8 is a plan view of FIG. 9. FIG. 10 is a section view taken along line D-D in FIG. 3.

[0031] An embodiment of a lining type butterfly valve according to the present invention will be described in detail below with reference to the drawings. Figure 1 shows a half cross-sectional view of an embodiment of a lining type butterfly valve according to the present invention, Figure 2 shows a cross-sectional view taken along line A-A in Figure 1, Figure 3 shows a cross-sectional view taken along line B-B in Figure 1, Figure 4 shows a cross-sectional view taken along line C-C in Figure 1, and Figure 5 shows a partially cutaway perspective view of Figure 1.

[0032] 1 to 5, a butterfly valve (hereinafter referred to as valve body 1) is used, for example, in semiconductor manufacturing plants and food-related pipelines, and is provided with a valve diameter of approximately 100 A to less than 300 A. Valve body 1 has a circular body 2, a seat liner 3, a disc 4, a backup rubber 5, and a stem 6, and this stem 6 has an upper stem 6a and a lower stem 6b.

[0033] The body 2 is formed, for example, from an aluminum alloy, which has lower strength than iron-based materials, and is provided in an upper and lower divided form by a semicircular upper body 2a and a semicircular lower body 2b. Both end portions 7, 7 of the upper and lower bodies 2a, 2b are formed with connecting portions 8 that protrude horizontally and can connect and fix both end portions 7. Furthermore, each connecting portion 8, 8 of the upper body 2a is formed with a female screw 10 into which a male screw 9a of a fastening member 9 made of a bolt can be threaded, and each connecting portion 8, 8 of the lower body 2b is formed with a communication hole 11 through which the fastening member 9 can be inserted.

[0034] Both the upper body 2a and the lower body 2b have cylindrical stem accommodating portions 13 formed to protrude in the centrifugal direction from the center of the outer peripheral side surface 12 of the body 2, and shaft mounting holes 14 for mounting the stems 6 are formed penetrating through the stem accommodating portions 13 to the inside of the bodies. The shaft mounting holes 14 of the upper body 2a and the lower body 2b are provided so that the upper stem 6a and the lower stem 6b can be inserted therein.

[0035] Rib portions 20 are provided on both sides of the stem accommodating portion 13 near the joints with the outer peripheral side surfaces 12 of the upper body 2a and the lower body 2b. The rib portions 20 are formed as plate-like portions with a substantially uniform thickness T and a rectangular cross section, extending from a midpoint in the height direction of the stem accommodating portion 13 toward the outer peripheral side surfaces 12 of the body. In this case, when the difference in linear distance between the center P of the disk mounted in the body 2 and the upper surface 20a of the rib portion 20 and the center P of the disk and the outer peripheral side surfaces 12 is defined as the height H of the rib portion, the height H of each rib portion is gradually reduced from the stem accommodating portion side toward the end of the body. Furthermore, when a force is applied to spread the semicircular upper and lower bodies 2a and 2b when connecting the upper body 2a and the lower body 2b, the height H of each rib portion is designed to accommodate stress near the stem accommodating portion 13. The rib portions 20 on the upper and lower sides of the body 2 are each provided in a bilaterally symmetrical shape.

[0036] The boundary 20b of the rib portion 20 with the outer peripheral side surface 12 of the body is formed to a position at least halfway from the stem accommodating portion 13 of the upper body 2a and the lower body 2b to the body end portion 7. In this embodiment, the boundary 20b of the rib is formed so that the angle from the center S of the stem accommodating portion 13 (the rotation axis of the stem) toward the body end portion 7 is 45° or more.

[0037] Furthermore, the vicinity of the boundary 20b between the rib portion 20 and the outer peripheral side surface 12 of the body is preferably formed in the tangential direction L of the outer peripheral side surface 12 of the body (the normal direction to the diameter of the body), and in this example, the vicinity of the boundary 20b is formed gradually in the direction almost tangential to the outer peripheral side surface 12 of the body.

[0038] Each rib portion 20 has a bolt insertion hole 21 formed at a predetermined position, communicating in the connection direction, which serves as a through hole for surface-to-surface connection with external piping, etc. (not shown).Through this bolt insertion hole 21, connection can be made between the external piping, etc. using a connecting bolt and nut (not shown).

[0039] On the inner peripheral surface of each of the upper and lower bodies 2a, 2b, which is the sealing side with the disc 4, a housing groove 22 having a generally U-shaped cross section is formed in an arc shape that continues from both sides of the journal hole 14 so as to be continuous and communicate with the journal hole 14. As will be described later, a backup rubber 5 is attached to the housing groove 22 of the upper and lower bodies 2a, 2b, and a seat liner 3 is attached to the inner peripheral surface of the body 2 with the backup rubber 5 interposed therebetween.

[0040] The seat liner 3 is made of a resin material, such as a fluororesin such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), and has a ring shape with a predetermined thickness. It has an annular portion 3a attached to the inner periphery of the body 2 and flange portions 3b protruding from the outer periphery of both ends of the annular portion 3a, and its cross section is generally U-shaped. Cylindrical lining portions 3c, 3c are integrally formed with the annular portion 3a at the positions of the upper and lower stems 6a, 6b, respectively, and the upper and lower stems 6a, 6b can be inserted through these cylindrical lining portions 3c. The seat liner 3 is arranged to cover the inner periphery of the upper and lower bodies 2a, 2b, and provides high corrosion resistance and heat resistance against the fluid flowing through the valve body 1. An arc-shaped inner periphery seal surface 3d is formed on the inner periphery of the seat liner 3, and the outer periphery 4a of the disc 4 can be sealed against this inner periphery seal surface 3d.

[0041] Inside the shaft mounting holes 14 of the upper and lower bodies 2a and 2b, there are respectively fitted a sealing bush 30, an O-ring 31, a bush 32 made of a rigid material, a bearing 33, a spring 34 made of a coil spring, and link members 35 and 36, through which the upper and lower stems 6a and 6b are fitted into the shaft mounting holes 14, thereby forming the shaft seal area.

[0042] When the disc 4 is open, the seat liner 3 can be deformed in the direction of reducing its diameter due to the elastic force of the backup rubber 5, while when the valve is closed, the seat liner 3 can be compressed and deformed in the direction of increasing its diameter against the elastic force of the backup rubber 5 due to the pressure of the outer peripheral surface 4a of the disc.

[0043] The sealing bushing 30 is molded from a resin material such as carbon fiber reinforced PTFE (polytetrafluoroethylene), and is fitted between a bushing 32 fitted in the mounting hole 14, a lining portion 37 (described later) provided on the disc 4, and the seat liner 3 to provide a seal. An O-ring 31 is fitted to the inner periphery of the sealing bushing 30 to seal between the outer periphery of the cylindrical lining portion 3c of the seat liner 3, and the bushing 32 is fitted to the outer periphery of the sealing bushing 30.

[0044] The bushing 32 is made of a metal material such as stainless steel and has an outer diameter that allows the end face 5a of the backup rubber 5 to abut against its outer peripheral surface. By fitting the bushing 32 inside the body 2, the boss surface side of the disk 4 is pressed, and the disk 4 is in a rotatable state, so that the resilient force of the spring 34 can be transmitted to the bushing 32 and the sealing bushing 30 via a bearing 33 provided on the outside in the mounting direction of the bushing 32 and the sealing bushing 30.

[0045] In the mounting hole 14, on the outside of the spring 34 in the mounting direction, the pieces 35 and 36 are attached in the stem accommodating portion 13 by engagement with retaining rings 38, and one side of the spring 34 is positioned by these pieces 35 and 36, so that the other end of the spring 34 is elastically urged in the centripetal direction of the mounting hole 14. As a result, the bushing 32 and sealing bushing 30 are each urged in the direction of the disk 4 via the bearing 33, and the seat liner 3 is pressed against the boss surfaces on the top and bottom sides (top and bottom sides) of the disk 4, ensuring sealing of these top and bottom portions.

[0046] The backup rubber 5 is made of an elastic rubber material such as FKM (fluoro rubber) or EPDM (ethylene propylene rubber) and has a predetermined width, height (thickness) and length. In this example, the backup rubber 5 has a substantially square cross section with approximately the same width and height, and is short in length.

[0047] More specifically, the width of the backup rubber 5 is set to a size that allows it to be accommodated in the accommodation groove 22 in a tight contact state, and the height is set to a size that allows the inner peripheral seal surface 3d of the seat liner 3 and the outer peripheral surface 4a of the disk to form a seal after being accommodated in the accommodation groove 22. The length of the backup rubber 5 is set to a dimension that is approximately divided into four in the circumferential direction of the body 2.

[0048] The four backup rubbers 5 are each mounted in the accommodation groove 22 and arranged in an annular shape on the back surface side of the seat liner 3. In this case, one end face 5a of each backup rubber 5 abuts against the outer circumferential surface of a bushing 32 mounted on the outer circumferential side of the stem 6, and the other end face 5a abuts against the end face 5a of the adjacent backup rubber 5, and the backup rubber 5 is accommodated in the accommodation groove 22 in a filled state.

[0049] The backup rubber 5 is mounted in the accommodation groove 22 with its elastic force secured against a certain crushing rate (compression rate), and the elastic force of this backup rubber 5 presses against the seat liner 3. When the disc 4 is closed, the inner peripheral seal surface 3d of the seat liner 3 is pressed in the radially contracting direction, increasing the pressing force with the outer peripheral surface 4a of the disc, thereby improving the sealing performance, particularly on the valve blade side.

[0050] One end face 5a of each backup rubber 5 on the top and bottom sides is preferably formed into a concave curved surface that fits along the outer circumferential surface of the bushing 32, while the other end face 5a is preferably formed flat. In this case, the one end face 5a of each backup rubber 5 on the bushing 32 side is brought into close contact with the bushing 32, while the other end faces 5a are brought into close contact with each other, allowing the backup rubbers 5 to be attached in a circularly positioned state on the left and right sides of the upper and lower bushings 32, as shown in Figure 1. This allows the backup rubber 5 to exert its pressing function on the seat liner 3 even near the boundary with the bushing 32, improving the sealing performance of the entire valve blade side approximately uniformly. Furthermore, both end faces 5a of the backup rubber 5 may be formed flat, in which case existing backup rubbers can be used without having to modify the end faces.

[0051] The disk 4 includes a core 40 and a lining 37, and is formed in a disk shape so that when the valve is closed, its outer surface 4a can abut and seal against the inner sealing surface 3d of the seat liner 3. The core 40 is formed in a disk shape using, for example, a stainless steel alloy, and the surface of the core 40 that comes into contact with the liquid is coated with a resin material such as a fluororesin such as PFA to a predetermined thickness to form the lining 37.

[0052] The lining portion 37 has a shaft tube lining portion 41 that covers the boss surfaces on the top and bottom sides of the disk 4 and part of the outer periphery of the stem 6, and is integrally coated around the outer periphery of the core wire 40 via a through hole 40a formed at an appropriate position in the core wire 40, and is integrated in a state that prevents it from coming off the core wire 40.

[0053] The top and bottom sides of the disk 4 are provided with top and bottom seal portions consisting of boss surfaces, and these top and bottom seal portions consist of the portions that the top and bottom portions contact and seal with, and the valve blade portions other than these top and bottom portions. As a result, the top and bottom portions ensure sealing on the top and bottom sides with the seat liner 3 from the valve open to the valve closed state, and the valve blade portions ensure sealing on the valve blade side with the seat liner 3 in the valve closed state. In the valve closed state, sealing by the top and bottom portions and the valve blade portions provides sealing over the entire inner peripheral surface of the seat liner 3.

[0054] A first stem insertion hole 42a is formed on the top side of the disk 4, and a square hole 43 is further formed in the top first stem insertion hole 42a. The upper stem 6a is inserted into the top first stem insertion hole 42a and the square hole 43. A second stem insertion hole 42b is formed on the bottom side of the disk 4, and the lower stem 6b is inserted into it. As a result, the disk 4 is journaled to the body 2 through the upper stem 6a and lower stem 6b, and is rotatable within the body 2 by operating the upper stem 6a.

[0055] As shown in Figure 9, the second stem insertion hole 42b may have a locking structure that allows the disk 4 and the lower stem 6b to rotate together. This locking structure is formed by a hexagonal recess in the second stem insertion hole 42b, and is provided so that it can be locked onto each side of the hexagonal shape of the lower stem 6b. Therefore, when the disk rotates relative to the body through operation of the upper stem 6a journaled in the first stem insertion hole, the upper stem 6a, the lower stem 6b, and the disk 4 rotate together. As a result, when the upper stem 6a is operated, the disk does not rotate because the lower stem is not rotating, and twisting or twisting of the lining layer covering the lower stem 6b is eliminated, preventing rupture of the lining layer.

[0056] The locking structure is not limited to the illustrated form, and can be any polygonal shape such as a square or octagon, a key structure, a serration structure, etc., as long as the disk and the lower stem can be linked together.

[0057] When constructing the valve body 1, the seat liner 3 is attached to the inner surface of the circular body 2 formed by connecting the upper body 2a and the lower body 2b, and the disc 4 is attached to the upper and lower stems 6a, 6b housed in the stem housing 13 via the seat liner 3. With a backup rubber 5 disposed between the seat liner 3 and the body 2, the upper and lower bodies 2a, 2b are pressed in the mounting direction while their connecting portions 8 are connected together with fastening members 9, thereby forming the circular body 2 into a single unit, and a flow path 44 is provided inside this body 2.

[0058] In the above embodiment, the stem accommodating portion 13 is formed in both the upper body 2a and the lower body 2b, but it is sufficient that the stem accommodating portion 13 is formed to protrude from the outer peripheral side surface 12 of at least one or both of the upper body 2a and the lower body 2b, and a reinforcing rib portion 20 is extended from midway in the protruding direction of the stem accommodating portion 13 toward the outer peripheral surface of one or both of the upper body 2a and the lower body 2b, and the rib portion 20 is provided on both sides near the joint with the upper body 2a and / or the lower body 2b.

[0059] The rib portion 20 may be provided in a shape other than a rectangular cross section with a uniform thickness T, for example, a cross section formed by combining plate-like portions of different thicknesses. Furthermore, the cross section of the rib portion 20 may be in a shape other than these, for example, various cross sections such as a substantially trapezoidal cross section may be provided.

[0060] In this embodiment, the rib portion 20 is provided with the bolt insertion holes 21, but it is also possible to omit the bolt insertion holes 21. When providing the bolt insertion holes 21 as in this embodiment, it is desirable to set the height H of the rib portion 20 from the stem accommodating portion 13 side to the boundary portion 20b, taking into account the reduction in strength of the rib portion 20 due to the bolt insertion holes 21.

[0061] The body 2 can be made of a material other than an aluminum alloy, such as a material that is weaker than an aluminum alloy (such as a soft or brittle material), or an iron-based material such as ductile cast iron that is stronger than an aluminum alloy. In this case, the strength of the entire body 2, particularly in the vicinity of the stem housing portion 13, can be further improved.

[0062] The cross-sectional shape of the backup rubber 5 is not limited to a substantially square shape, and may be an appropriate cross-sectional shape such as a substantially rectangular shape depending on the cross-sectional shape of the accommodation groove 22. The backup rubber 5 is divided into left and right halves on the top and bottom sides of the body 2, but may be formed integrally on the top and bottom sides. In this case, the backup rubber has a shape divided into two substantially semicircular shapes.

[0063] The fastening member 9 may be a member other than a bolt, and it is also possible to connect the upper body 2a and the lower body 2b using various connecting members such as bolts and nuts.

[0064] Next, we will describe the assembly procedure and operation of the above-described embodiment of the valve body 1. When assembling the valve body 1 as shown in Figures 1 to 5, first, internal parts such as the seat liner 3, disc 4, sealing bush 30, bush 32, bearing 33, spring 34, and link members 35 and 36 are temporarily assembled to the upper and lower bodies 2a and 2b.

[0065] In this case, first, the upper and lower axial cylindrical lining portions 41 of the disk 4 are inserted into the upper and lower cylindrical lining portions 3c of the seat liner 3, respectively, and the disk 4 is positioned at a predetermined position on the inner circumference of the seat liner 3, and then the sealing bush 30 equipped with an O-ring 31 is attached to the outer circumference of the cylindrical lining portion 3c.

[0066] A bushing 32 is attached to the outer periphery of the sealing bushing 30, so that the sealing bushing 30 is held from the outer periphery by the rigid metal bushing 32 while the sealing performance is ensured by the O-ring 31. In this state, the upper stem 6a and the lower stem 6b are inserted into the first stem insertion hole 42a and the second stem insertion hole 42b of the disk 4, respectively.

[0067] Next, the bearing 33, spring 34, and link members 35, 36 are mounted in each of the mounting holes 14 of the upper body 2a and the lower body 2b, and a retaining ring 38 is mounted on the outer periphery of each of the link members 35, 36. The retaining ring 38 is engaged with the inner periphery of the mounting hole 14 to prevent the sealing bush 30, bush 32, bearing 33, spring 34, and link members 35, 36 from coming loose, leaving these internal parts in a pre-assembled state.

[0068] The four backup rubbers 5 are fitted into the accommodation groove 22 with one end face 5a on the top and bottom sides tightly attached to the outer periphery of the bush 32, which is the shaft seal portion, and the other end face 5a abutting against the opposing end face 5a of the backup rubber 5 adjacent to this backup rubber 5.

[0069] The temporary assembly of the internal components to the body 2 and the assembly of the valve main body 1 after the temporary assembly are performed using a pressing jig 50 shown in Fig. 6. The pressing jig 50 includes an upper jig 51 and a lower jig 52. The upper jig 51 includes an upper pressing portion 51a that protrudes downward, and the lower jig 52 includes a pedestal-shaped lower pressing portion 52a that protrudes upward.

[0070] In the manufacturing method of the lining type butterfly valve of this invention, when connecting the upper body 2 a and the lower body 2 b using the above-mentioned pressing jig 50, a pressing process in which both end connecting portions 8 are abutted and pressed, and a tightening process in which the fastening members 9 are tightened are repeated, thereby forming the body into an integrated unit while responding to stresses in the vicinity of the stem accommodating portion 13.

[0071] Before pressing with the press jig 50, as shown in Figure 6 (a), the upper body 2a is turned upside down, and the stem accommodating section 13 located on the lower side is placed on and held by the lower press section 52a. In this state, the internal parts such as the seat liner 3, disc 4, stem 6, sealing bush 30, bush 32, bearing 33, spring 34, and link members 35 and 36 are placed in their predetermined positions as described above, and the lower body 2b is then placed so as to cover the upper body 2a from above.

[0072] At this time, the seat liners 3 are attached to the inner peripheries of the upper body 2a and the lower body 2b, respectively, and in this state, the connecting portions 8 at both ends of the upper body 2a and the lower body 2b are connected by fastening members 9.

[0073] In this case, the male screws 9a of the fastening members 9 are inserted from above into the communicating holes 11 on both sides of the lower body 2b, and the fastening members 9 are tightened to such an extent that the bottom surface of the heads 9b of the fastening members 9 comes into contact with the upper surface of the connecting portion 8 of the lower body 2b in Figure 1, so as to place them in a temporarily fastened state, so that almost no load (pressing force) is applied to the seat liner 3 or the backup rubber 5.

[0074] Furthermore, the upper side of the stem accommodating portion 13 of the lower body 2b located on the upper side is held by the upper press portion 51a of the upper jig 51. Figure 6(a) shows the state before the upper body 2a is clamped by the lower jig 52 and the lower body 2b is pressed downward by the press of the upper jig 51.

[0075] In this state, in the pressing process, pressing is performed from the outside of the stem housing portion 13 with the pressing jig 50 in the mounting direction of the upper and lower bodies 2a, 2b. At this time, a hole (not shown) is provided in the lower pressing portion 52a at a position opposite the top surface of the upper stem 6a, and the upper stem 6a protruding from the stem housing portion 13 of the upper body 2a is inserted into this hole to allow it to escape, thereby preventing the upper stem 6a from contacting the lower pressing portion 52a and preventing the lower body 2b from tilting.

[0076] When a predetermined pressing force is applied to this temporary assembly state using the pressing jig 50, this force is applied to the body 2 from the upper part of the disk 4 and the inner periphery of the upper body 2a facing the disk 4 (the inner upper surface side of the seat liner 3), and from the lower part of the disk 4 and the inner periphery of the lower body 2b facing the disk 4 (the inner lower surface side of the seat liner 3). As a result, a force that tries to crush the backup rubber 5 is transmitted from the vicinity of the upper and lower stems 6a, 6b in the circumferential direction of the body 2. Accordingly, the elastic repulsive force of the backup rubber 5 that opposes this crushing force increases from the vicinity of the stem accommodating portion 13 of the upper and lower bodies 2a, 2b toward both ends, and this repulsive force generates stress in the upper and lower bodies 2a, 2b. Figure 6(b) shows the state in which the lower body 2b has been pressed downward from the state shown in Figure 6(a) by the pressing jig 50.

[0077] In this case, the arc-shaped outer peripheral side surface 12 of the upper and lower bodies 2a, 2b is formed so as to be attached to the stem accommodating portion 13, and the attachment portion of the stem accommodating portion 13 and the outer peripheral side surface 12 is, so to speak, the fixed end side of both sides. Due to this shape, the backup rubber 5 close to this portion is crushed by the pressing force in the attachment direction of the upper and lower bodies 2a, 2b to the stem accommodating portion 13, and this crushed portion deforms so as to escape from the stem accommodating portion 13 side to the end portion 7 side.

[0078] This deformation increases the compression rate of the backup rubber 5 near both end portions 7 of the upper and lower bodies 2a, 2b, increasing its repulsive force and exerting a force that tries to push them apart toward both end portions 7. This force acts to its maximum from both end portions 7 toward the stem housing portion 13, which is the fixed end side, and at the same time, the upper body 2a and lower body 2b move and deform in directions that gradually bring them closer to each other.

[0079] As described above, when a pressing force is applied, the repulsive force of the backup rubber 5 gradually increases in the circumferential direction of each of the upper and lower bodies 2a, 2b from near the stem accommodating portion 13 toward both end portions 7, and therefore the stress generated in the body 2 due to this repulsive force also gradually increases from both end portions 7 of the upper and lower bodies 2a, 2b toward the stem accommodating portion 13, reaching a maximum near the stem accommodating portion 13.

[0080] In this way, in each of the upper and lower bodies 2a and 2b, the point where the repulsive force of the backup rubber 5 is greatest is the stem housing portion 13 side where the end portions 7 of the upper and lower bodies 2a and 2b are pushed apart and the greatest force acts, resulting in excessive stress occurring near the stem housing portion 13. This stress decreases in approximately proportional fashion from the stem housing portion 13 toward the end portions 7.

[0081] To cope with such stress generation, the valve body 1 in the above embodiment of the present invention is provided with a rib portion 20 that extends from the middle of the stem housing portion 13 toward the outer circumferential side surface 12 of the body, and the height H of this rib portion 20 gradually decreases from the stem housing portion 13 side toward both end portions 7 of the body 2, so that if a force is applied to spread the semicircular upper and lower bodies 2a, 2b when connecting the upper body 2a and the lower body 2b, it can accommodate the stress near the stem housing portion 13. Specifically, the strength of the rib portion 20 on the stem housing portion 13 side is set to be greatest, and the strength gradually decreases proportionally from the stem housing portion 13 side toward both end portions 7.

[0082] As a result, the rib portion 20 can improve the body strength in response to the magnitude of the stress that increases proportionally toward the stem housing portion 13 of the upper and lower bodies 2a, 2b, without locally increasing the strength of the stem housing portion 13 side of the body 2, and can avoid local stress concentration, particularly stress concentration near the stem housing portion 13, and make the stress generated by pressing more uniform. As a result, even if the body 2 is made of aluminum, which is weaker in strength than iron-based materials, it is possible to ensure sufficient strength against the pressing force during assembly and to connect the upper body 2a and the lower body 2b while effectively preventing deformation and cracking.

[0083] In this case, the strength of the rib portion 20 is determined by its "height H x thickness T", and when providing the rib portion 20, this "height H x thickness T" is set so that it is greatest on the stem accommodating portion 13 side and the strength gradually decreases from the stem accommodating portion 13 side toward both end portions 7.

[0084] In this embodiment, the thickness T of the rib portion is set to be approximately uniform, so the strength of the rib portion 20 is determined largely by its height H. By setting the height H of the rib portion 20 to gradually decrease from the stem housing portion 13 side toward the end portion 7 side, the strength is gradually weakened and local stress concentration is prevented. In this way, when the thickness T of the rib portion 20 is set to be constant, the strength of the rib portion 20 can be easily set according to the generated stress by setting the height H from the stem housing portion 13 side toward the end portion 7 side.

[0085] Furthermore, if the height H of the rib portion is made substantially uniform, its strength can be set by changing the thickness T. For example, by making the thickness T of the rib portion gradually smaller from the stem accommodating portion 13 side toward the body end 7 side, it is possible to keep the height H of the rib portion constant while making the strength gradually weaker from the stem accommodating portion 13 side toward the body end 7 side. Furthermore, by making the thickness T and height H of the rib portion 20 into a shape that changes, its strength can also be set.

[0086] A backup rubber 5 is attached between the accommodation groove 22 of the upper and lower bodies 2a, 2b and the seat liner 3, and the elastic repulsive force of this backup rubber 5 presses the seat liner 3 toward the disc 4, providing sufficient sealing with the lining portion of the disc 4, and the chemical resistance and heat resistance of the fluororesin are exhibited to reliably prevent leakage when the valve is closed.

[0087] The backup rubber 5 is accommodated in the accommodation groove 22 with one end face 5a abutting against the outer circumferential surface of the bushing 32 and the other end face 5a abutting against the end face 5a of the adjacent backup rubber 5, so that when the body 2 is pressed with the pressing jig 50, the valve body 1 can be assembled with the pressing force being transmitted evenly to the seat liner 3 via the backup rubber 5. As a result, when the valve body 1 is closed after assembly, the outer surface of the seat liner 3 is pressed evenly against the lining portion of the disc, improving the adhesion between them and providing excellent sealing performance.

[0088] During the above-mentioned pressing operation, a pressing force is applied little by little, i.e., intermittently, to the temporarily assembled upper and lower bodies 2 a, 2 b from the state shown in Fig. 6(a). When a small amount of pressing is applied by the pressing jig 50, this pressing brings the upper and lower bodies 2 a, 2 b closer to each other as shown in Fig. 6(b), creating a gap between the bottom surface of the head 9 b of the temporarily fastened fastening member 9 and the upper surface of the connecting portion 8 of the lower body 2 b by the amount that the upper and lower bodies 2 a, 2 b have come closer, and the head 9 b is raised above the upper surface of the connecting portion 8 of the lower body 2 b.

[0089] In response to this, in the tightening process for tightening the fastening members 9, the fastening members 9 are tightened until the bottom surface of the raised bolt heads 9b contacts the upper surface of the connecting portion 8. This allows the fastening members 9 (bolt heads 9b) to bear the force that tries to spread apart both end portions 7 of the body 2, which is generated by pressing, and relieves the stress that has been generated on the stem housing portion 13 side by pressing.

[0090] Next, by repeating the same process as above, a small amount of pressing using the pressing jig 50 and a tightening process in which any gaps created by this pressing are filled by tightening the fastening members 9, the stress created by the pressing is released toward the fastening members 9 each time, preventing excessive stress from being generated all at once in the stem housing portion 13, and completely connecting the upper and lower bodies 2a, 2b to assemble the valve body 1 as a whole. After the valve body 1 is assembled, the majority of the stress caused by the elastic repulsive force of the backup rubber 5 is borne by the fastening members 9 on both sides, so almost no stress is applied to the stem housing portion 13 side.

[0091] Although not shown, in order to stably hold the upper and lower bodies 2a, 2b when assembling the valve body 1, in addition to the above-mentioned pressing jig 50, another jig may be used to support the upper and lower bodies 2a, 2b.

[0092] 7 and 8 show another embodiment of the lining type butterfly valve of the present invention. In this embodiment, the same parts as those in the above embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[0093] The valve body 60 in this embodiment is suitable for installation in a valve having a larger diameter than the valve body 1 of the previous embodiment, for example, a valve diameter of 300A or more, and for each of the upper body 61a and lower body 61b that make up the body 61, the rib portions 62 are formed at approximately the same height from the outer peripheral side surface 12 of the body in the vertical direction in Figure 7 from the stem accommodating portion 13 side toward both end portions 7.

[0094] 8, the rib portion 62 has a thick rib portion 63 on the stem housing portion 13 side and thin rib portions 64 that are thicker on both end sides than the thick rib portion 63, and is formed by combining these two different rib portions 63, 64. As a result, as in the previous embodiment, the strength of the upper and lower bodies 61a, 61b is improved mainly near the stem housing portion 13, and this strength can be gradually reduced toward the end sides 7, thereby preventing deformation and cracking when the upper and lower bodies 61a, 61b are connected during assembly of the valve body 60.

[0095] In this way, even when the body 61 is enlarged by increasing the diameter or the like, the rib portion 62 can prevent the rib portion 62 from becoming larger in the outer diameter direction or from partially protruding, while improving the strength of the area around the stem accommodating portion 13. As a result, a sufficient space can be secured around the flange portion 65 provided on the upper part of the stem accommodating portion 13, and as shown in the figure, for example, when an operating actuator 66 is mounted on the flange portion 65, the operating actuator 66 can be reliably mounted in a predetermined state without the rib portion 62 getting in the way, and after mounting, when the handle portion 67 of the actuator 66 is operated, the handle portion 67 does not come into contact with the rib portion 62, and the handle portion 67 can be operated smoothly.

[0096] In addition to the above, the rib portion can be provided in various shapes, and as mentioned above, by appropriately setting the height and thickness of the rib portion, or by appropriately setting the size and shape of the rib portion, it is possible to provide upper and lower bodies that can ensure strength against stress applied near the stem accommodating portion during assembly.

[0097] The above describes in detail the embodiments of the present invention, but the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the spirit of the invention described in the claims of the present invention.

[0098] REFERENCE SIGNS LIST 1 Valve body 2 Body 2a Upper body 2b Lower body 3 Seat liner 4 Disc 5 Backup rubber 5a End face 6 Stem 7 End 9 Bolt (fastening member) 12 Body outer peripheral side surface 13 Stem accommodating portion 20 Rib portion 20a Upper surface 20b Boundary portion 21 Bolt insertion hole 22 Accommodating groove 32 Bush 42a First stem insertion hole 42b Second stem insertion hole 42c Locking structure P Center of disc H Rib height L Tangent line of body outer peripheral side surface

Claims

1. In a lining type butterfly valve in which a seat liner is mounted on the inner peripheral surface of a circular body formed by connecting a semi-circular upper body and a semi-circular lower body, a cylindrical stem accommodating portion projects from the outer peripheral side surface of at least one of the upper body or the lower body, and ribs extending from an intermediate position of the stem accommodating portion toward the outer peripheral side surface of the body are provided on both sides near the joint portion of the stem accommodating portion with the upper body and / or the lower body. When the height of each rib is defined as the difference between the straight-line distance from the center of the disk to the upper surface and the straight-line distance from the center of the disk to the outer peripheral side surface of the body, the height of each rib is provided so as to gradually decrease from the side of the stem accommodating portion toward the end side of the body. When a force for expanding the semi-circular upper and lower bodies is applied when connecting the upper body and the lower body, the lining type butterfly valve is characterized in that it can cope with the stress near the stem accommodating portion.

2. The lining type butterfly valve according to claim 1, wherein a backup rubber is mounted in an accommodation groove formed on the inner peripheral surface of each of the upper and lower bodies, and the seat liner is mounted on the inner peripheral surface of the body with the backup rubber interposed therebetween.

3. The lining type butterfly valve according to claim 1 or 2, wherein the boundary portion near the outer peripheral side surface of the body of the rib portion is formed up to a position exceeding at least half of the distance from the stem accommodating portion to the end of the body in the upper body and / or the lower body.

4. The lining type butterfly valve according to claim 1 or 2, wherein the boundary portion near the outer peripheral side surface of the body of the rib portion is formed in the tangential direction of the outer peripheral side surface of the body.

5. The lining type butterfly valve according to claim 1 or 2, wherein a bolt insertion hole for surface connection is formed in the rib portion.

6. The disk has a first stem insertion hole for axially mounting an upper stem on the top side, and the disk has a second stem insertion hole for axially mounting a lower stem on the bottom side. The second stem insertion hole has a locking structure that enables the disk and the lower stem to rotate integrally. The disk is configured to be rotatable with respect to the body through the operation of the upper stem axially mounted in the first stem insertion hole. The lining type butterfly valve according to claim 1 or 2.

7. Connect both end connection parts of a semi-circular upper body with a seat liner attached to its inner circumference and a semi-circular lower body with a seat liner attached to its inner circumference with a fastening member, project a cylindrical stem accommodating part on one or both of the upper body or the lower body, and provide a reinforcing rib part extending from the middle of the protruding direction of the stem accommodating part toward the outer peripheral surface of one or both of the upper body or the lower body. When the height of each rib part is the difference between the straight-line distance from the center of the disk to the upper surface and the straight-line distance from the center of the disk to the outer peripheral side surface of the body, the height of each rib part is provided so as to gradually decrease from the side of the stem accommodating part toward the end side of the body. When connecting the upper body and the lower body, by repeating a pressing process of abutting and pressing the both end connection parts and a tightening process of tightening the fastening member, when a force for expanding the semi-circular upper and lower bodies is applied, it is characterized in that it can cope with the stress near the stem accommodating part. A manufacturing method of a lining type butterfly valve.

8. The manufacturing method of the lining type butterfly valve according to claim 7, wherein a backup rubber is attached to an accommodation groove formed on each inner peripheral surface of the upper and lower bodies, and the seat liner is attached with the backup rubber interposed on the inner peripheral surface of the body.

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