Eccentric butterfly valve

Abstract

The present application provides an eccentric butterfly valve which maintains high sealing performance when the valve is closed in any direction of positive flow or reverse flow of high pressure fluid, particularly maintains the sealing performance of the seat ring even when high pressure is applied due to reverse flow, can ensure the sealing surface pressure of the seat ring and the disc to prevent leakage, and is excellent in operability. A disc (23) supported in an eccentric position via a valve stem (22) in a valve body (21) is sealably provided to a seat ring (24) fixed by a seat ring (25). A flexible portion (41) is formed on the inner diameter side of the seat ring (24), and a spring member (26) is fitted between the flexible portion (41) and the seat ring (25). The spring member (26) is such that the load increases in proportion to the size of the tilting of the flexible portion (41) when the disc (23) is displaced to the seat ring (25) side. When the flexible portion (41) is elastically deformed, the spring member (26) is elastically deformed in a state avoiding contact with the seat ring (25).

Description

Technical Field

[0001] This invention relates to eccentric butterfly valves suitable for high-pressure fluids, and in particular, to eccentric butterfly valves corresponding to bidirectional flow, both forward and reverse. Background Technology

[0002] Previously, eccentric butterfly valves were generally known as suitable for high-pressure fluids. Among them, for example, in a double eccentric butterfly valve, the valve shaft is eccentrically positioned relative to the valve body towards the flow path, and the center of rotation of the valve body is eccentrically positioned from the center of the valve orifice. Therefore, compared to a center-type butterfly valve, the sealing performance when closed is improved. In such valves, it is sometimes necessary to improve the sealing performance not only relative to the pressure in the forward flow direction (positive pressure) but also relative to the pressure in the reverse flow direction (back pressure). To cope with such bidirectional pressures, known as dual-flow, it is particularly necessary to improve the seat seal durability in the back pressure direction.

[0003] As an eccentric butterfly valve corresponding to the dual-flow direction, for example, the eccentric butterfly valve of Patent Document 1 filed by the applicant. In this eccentric butterfly valve 1, such as Figure 8 As shown in a partially enlarged schematic diagram, the annular integral seat ring component 4 is located between the valve box 2 and the seat ring component 3. The seat ring component 4 has a flexible portion 5 on its inner diameter side that is flexible in the forward or reverse flow direction.

[0004] When the butterfly valve 1 is closed, and a positive flow is generated, the valve body 6 in the valve box 2 will move away from the seat ring component 4 (secondary side: right side in the figure) due to the fluid pressure (positive pressure). However, due to the self-sealing function based on the fluid pressure, the flexible part 5 tilts towards the valve body 6 (right side) and pushes the valve body 6. As a result, the sealing surface pressure between them is maintained, and the valve seat sealing is maintained.

[0005] On the other hand, when backflow occurs, the valve body 6 moves toward the seat ring component 4 (primary side: left side in the figure) due to the fluid pressure (backflow) and pushes the seat ring component 4. The flexible part 5 of the seat ring component 4 is pushed toward the opposite surface of the seat ring component 3 and compressed, thereby exerting the valve seat sealing property under backflow.

[0006] Furthermore, in the double eccentric butterfly valve of Patent Document 2, the seat ring component is provided by a combination of a resin seat ring and a metal seat ring, and the end side (flow path side) of the seat ring component can flex in accordance with the forward or reverse flow direction. The seat ring component is assembled to the valve box via a seat ring component, and a metal disc spring is assembled between these seat ring portions and the seat ring component.

[0007] When the valve is closed and a positive flow is generated, the valve body moves away from the seat ring component due to the positive pressure, and the fluid enters from the gap between the metal seat ring and the valve body, pushing the seat ring component. As a result, the end of the resin seat ring deforms in response to the movement of the valve body, pushing the valve body to maintain the contact surface pressure between them and thus maintain the valve seat seal.

[0008] On the other hand, when backflow occurs, the valve body moves towards the seat ring component due to the back pressure, applying a force in the direction of compressing the resin seat ring, causing the resin seat ring to move in that direction. In this case, the rebound force of the disc spring disposed on the back of the metal seat ring pushes both the metal seat ring and the resin seat ring back, maintaining the contact surface pressure between the resin seat ring and the valve body necessary for fluid closure, thereby preventing leakage during back pressure.

[0009] However, such dual-flow eccentric butterfly valves are considered, for example, as part of the piping of central air conditioning (CHP) equipment installed in buildings such as high-rise buildings.

[0010] Figure 9 (a) shows a schematic diagram of a typical central air conditioning system 10, in which the cooler (heat source unit) 11, cooling tower 12, etc., are installed underground and on the roof, and are connected to a circulating piping system 13. A branching path (not shown) is provided at the longitudinal piping 14 of the piping system 13, which connects to the air conditioning systems (air conditioners) on each floor. When the central air conditioning system 10 is operating, chilled or heated air conditioning water, cooled or heated by the heat source unit 11, circulates within the piping system 13, passes through the branching pipes, and is delivered to the air conditioning systems on each floor, thereby providing overall air conditioning for the building, including cooling and heating.

[0011] Sometimes, the central air conditioning unit 10 uses an eccentric butterfly valve 1 corresponding to the aforementioned dual-flow type. In this case, the butterfly valve 1 is respectively disposed on the lower side (lower floor side) of the longitudinal piping 14 on the upstream and downstream sides of the piping 13. Each butterfly valve 1 is mounted at both ends of the primary and secondary sides by means of piping bolts (not shown in the figure) with a connecting flange 15, and is clamped between the longitudinal piping 14 via the connecting flange 15. Each butterfly valve 1 is provided with an automatic or manual opening and closing operation unit 16, which is configured to allow opening and closing operation via the opening and closing operation unit 16.

[0012] Figure 9 When the central air conditioning equipment (a) is in operation, the pump 17 delivers cooling or heating cold water from the heat source unit 11. The cold water circulates in the piping 13 in a manner that the vertical piping 14 on the left side of the figure rises and the vertical piping 14 on the right side of the figure descends. It is then supplied from the vertical piping 14 through the horizontal piping to each floor.

[0013] on the other hand, Figure 9In (b), when performing maintenance on the central air conditioning equipment 10, with the central air conditioning equipment 10 stopped, the upstream and downstream butterfly valves 1 are operated to the closed state using the opening and closing operation unit 16. A portion of the connecting flange 15 and piping 13 on the lower side (lower floor side) of these butterfly valves 1 are disassembled, thereby bringing the end of the butterfly valve 1 to a so-called end point (terminal). This divides the flow path on the lower side of the butterfly valve 1, allowing for cleaning of the piping on the upper side (higher floor side) or lower side of the butterfly valve 1.

[0014] Patent document 1: Japanese Patent No. 6144847.

[0015] Patent Document 2: Japanese Patent Application Publication No. 2007-78001.

[0016] In the case of an eccentric butterfly valve with a sealing structure like that in Patent Document 1, Figure 8 When reverse pressure is applied, the valve body 6 moves towards the seat ring component 4 in accordance with the magnitude of the pressure, thereby increasing the force applied to the flexible portion 5 of the seat ring component 4. At this time, when the reverse pressure increases, the flexible portion 5 is crushed by the mating surface of the seat ring component 3, and the flexible portion 5 undergoes plastic deformation exceeding the allowable stress of the seat ring component 4. The wear of the seat ring component 4 caused by the operation of the valve body 6 increases, and there is a possibility that the sealing surface pressure will be greatly reduced, and the valve seat sealing function may fail.

[0017] On the other hand, in the latter patent document 2, when reverse pressure is generated, the seat ring component is pushed back to the secondary side by means of a disc spring. However, since the structure is such that the pushing force acts approximately constant, in the case of high reverse pressure, the disc spring may be unable to withstand the pressure and deform significantly, making it impossible to push the seat ring component back. In this case, if excessive pushing force is continuously applied to the flexible part of the seat ring component, there is a possibility of plastic deformation at the end side and valve seat leakage.

[0018] Furthermore, in double eccentric butterfly valves, the pressure-bearing areas of the valve body on the left and right sides of the valve stem are different. Therefore, in the aforementioned butterfly valves, a rotational force is generated at the valve stem proportional to the fluid pressure, and a rotational force in the valve stem in the valve-closing direction is generated when pressure is reversed. The increased sealing surface pressure caused by the movement of the valve body also increases the unbalanced torque exerted on the valve stem by the aforementioned fluid pressure, resulting in a larger operating load torque. Consequently, especially during automatic operation, a rapid working (abrupt change) occurs when opening from a fully closed state, and this rapid working can lead to severe wear of the seat ring, resulting in a decrease in durability.

[0019] Furthermore, when the aforementioned eccentric butterfly valve is installed in the piping of centralized air conditioning equipment in buildings such as high-rise buildings, Figure 9In (b), when maintenance is performed and the endpoint is set, gravity is generated in the water in piping 13, and this water pressure is applied to the valve bodies of butterfly valves 1 on both sides. In this case, reverse pressure is applied to butterfly valve 1 on the upstream side (left side in the figure) in the direction of the arrow. If the longitudinal piping is extended as the building becomes taller, the fluid pressure of the reverse pressure increases.

[0020] In contrast, the connecting flange 15 on the lower side of the butterfly valve 1 is removed, so the tightening force of the pipe bolts that push the seat ring component is completely eliminated, and the force that pushes the seat ring component between the valve box and the seat ring component is only the tightening force of the stop bolts used to fasten the seat ring component.

[0021] In this state, if a high-pressure reverse pressure is applied to butterfly valve 1, the movement of the valve body will also increase significantly. Figure 8 Due to the reverse pressure, the valve body 6 moves to the left, and the seat ring component 4 is pushed more forcefully towards the seat ring component 3, resulting in more severe plastic deformation. The seat ring component 4 is pushed towards the seat ring component 3, thereby separating the seat ring component 4 from the valve box 2, and the sealing surface pressure on the back of the base portion of the seat ring component 4 also decreases. If the sealing surface pressure of this base portion decreases, it also leads to so-called internal leakage, which causes fluid leakage from this portion.

[0022] Furthermore, when the seat ring component 4 was initially tightened using the stop bolt, the connecting flange 15 was temporarily tightened due to insufficient tightening force. When the connecting flange 15 on the lower side was removed at the final position, the stop bolt loosened and the sealing surface pressure decreased. As a result, the sealing surface pressure at the base end of the seat ring decreased, leading to further internal leakage. Summary of the Invention

[0023] This invention was developed to solve previous problems. Its purpose is to provide an eccentric butterfly valve that maintains high sealing performance when the valve is closed, whether the pressure of the high-pressure fluid is applied in the forward or reverse direction. In particular, it maintains the sealing performance of the seat ring even when high pressure is applied due to the reverse flow, and can ensure the sealing surface pressure between the seat ring and the disc to prevent leakage, and has excellent operability.

[0024] To achieve the above objectives, the invention of technical solution 1 is an eccentric butterfly valve. The aforementioned eccentric butterfly valve has a disc rotatably supported at an eccentric position within a cylindrical valve body via a valve stem. This disc is sealed within a seat ring fixed by a seat ring within the valve body. A flexible portion is formed on the inner diameter side of the seat ring, tilting in accordance with the displacement of the disc. A spring component is assembled between the flexible portion and the seat ring to spring them back to each other. This spring component is assembled such that when the disc displaces towards the seat ring in the flow direction, the load in the rebound direction increases in accordance with the magnitude of the tilt of the flexible portion caused by the displacement of the disc. When the flexible portion elastically deforms, the spring component, which is pushed by the flexible portion, elastically deforms in a state that avoids contact with the seat ring. Furthermore, it is assembled in a state where the contact position between the flexible portion and the seat ring gradually shifts from the inner diameter side to the outer diameter side as the tilt of the flexible portion increases.

[0025] The invention of technical solution 2 is an eccentric butterfly valve, in which the spring component is composed of a ring-shaped leaf spring. The leaf spring is assembled such that, with the outer diameter side abutting against the opposite side of the seat ring and the inner diameter side abutting against the flexible part against the opposite side of the seat ring, as the tilting of the flexible part increases, the abutting position with the seat ring gradually shifts from the inner diameter side to the outer diameter side.

[0026] The invention of technical solution 3 is an eccentric butterfly valve, in which an annular abutment surface is formed on the side opposite to the leaf spring in the flexible part, and the annular abutment surface is composed of a conical surface that is inclined at a predetermined angle from the inner diameter side to the outer diameter direction.

[0027] The invention of technical solution 4 is an eccentric butterfly valve, wherein an annular protrusion with a trapezoidal cross-section is formed on the seat ring on the side that abuts against the leaf spring. At the outer diameter position of the annular protrusion, an annular abutment portion is formed that abuts against the leaf spring through line contact and becomes the fulcrum when the leaf spring is elastically deformed. On the inner diameter side of the annular abutment portion, a gap portion is formed to prevent contact with the tipping part of the spring component.

[0028] The invention of technical solution 5 is an eccentric butterfly valve, wherein the outer diameter end of the annular abutment surface is arranged on the inner diameter side relative to the normal of the leaf spring at the abutment position between the annular abutment part and the leaf spring.

[0029] The invention of technical solution 6 is an eccentric butterfly valve, wherein a fixing part is integrally formed on the outer diameter side of the flexible part and is fixed between the valve body and the seat ring, and a gasket part is integrally connected to the outer peripheral surface of the fixing part by a thin-walled part and sandwiched between the valve body and the seat ring.

[0030] The invention of technical solution 7 is an eccentric butterfly valve in which, in the sealed state between the seat ring and the disc, the seat ring is fastened and fixed between the valve body and the seat ring by a fastening stop bolt.

[0031] Invention Effects

[0032] According to the invention of technical solution 1, an eccentric valve structure is provided, with a flexible portion tilting in accordance with the displacement of the disc on the inner diameter side of the seat ring. This ensures high sealing performance when the valve is closed, regardless of whether the pressure of the high-pressure fluid is applied in the forward or reverse flow direction. In this case, a spring component is assembled between the flexible portion and the seat ring. The load of the spring component in the rebound direction increases in accordance with the tilt of the flexible portion. Therefore, particularly when high pressure is applied due to reverse flow, the sealing surface pressure of the seat ring and disc can be increased in accordance with the magnitude of the pressure to reliably prevent leakage. When the flexible portion elastically deforms, the spring component deforms while avoiding contact with the seat ring. Therefore, even if the flexible portion deforms excessively due to high pressure reverse pressure, contact between the spring component and the seat ring on the flexible portion side is prevented, suppressing a rapid increase in sealing surface pressure. This allows deformation of the flexible portion and increases the sealing surface pressure to prevent leakage, maintaining the elastic characteristics of the seat ring and preventing wear, breakage, plastic deformation, etc., thus preserving the valve seat's sealing performance under both reverse and forward pressure when the valve is closed. Furthermore, during reverse pressure, the rebound force of the spring component reduces the load torque caused by fluid pressure. Therefore, it improves operability by preventing sudden changes in the disc's operation during automatic operation, and also improves durability by preventing wear on the seat ring caused by such changes. In this configuration, the spring component is assembled such that the contact position with the seat ring gradually shifts from the inner diameter side to the outer diameter side as the flexible part tilts more. Therefore, as the reverse pressure on the disc increases and the flexible part tilts more, the spring load on the leaf spring increases approximately proportionally. Thus, even when excessive reverse pressure is applied to the disc, the load from the spring component in the rebound direction gradually increases the sealing pressure between the seat ring and the disc, preventing leakage and also preventing plastic deformation of the flexible part.

[0033] According to the invention of technical solution 2, the spring component, which is made of leaf springs, abuts against the opposite side of the seat ring on its outer diameter side and against the opposite side of the seat ring on its inner diameter side, respectively. Therefore, when a force is applied from the flexible part of the seat ring due to reverse pressure, the abutting side towards the seat ring serves as a fulcrum, and the inner diameter side of the spring component elastically deforms. At this time, the spring component is assembled in a state where the abutting position with the seat ring gradually shifts from the inner diameter side to the outer diameter side as the flexible part tilts more. Therefore, as the reverse pressure towards the disc increases and the flexible part tilts more, the spring load of the leaf spring also increases approximately proportionally. Thus, even when excessive reverse pressure is applied to the disc, the sealing surface pressure between the seat ring and the disc is gradually increased by the load from the spring component in the springback direction to prevent leakage, and plastic deformation of the flexible part can also be prevented.

[0034] According to the invention of technical solution 3, on the side of the flexible part opposite to the leaf spring, an annular abutment surface is formed, which is composed of a conical surface inclined at a predetermined angle from the inner diameter side to the outer diameter side. Therefore, when the flexible part tilts towards the spring component, the inner diameter side of the flexible part gradually shifts from abutting the spring component to the outer diameter side as the amount of tilting increases. Consequently, as the reverse pressure towards the disc increases, the load in the spring component's return direction gradually increases. This spring load suppresses the tilting of the seat ring and increases the pressure on the sealing surface with the disc. By changing the inclination angle of the annular abutment surface, the return force of the leaf spring relative to the tilting amount of the flexible part can be changed. Therefore, the elastic deformation of the flexible part can be changed in accordance with the magnitude of the generated reverse pressure to ensure the valve seat sealing performance.

[0035] According to the invention of technical solution 4, when force is applied to the flexible part, the annular abutment portion becomes a fulcrum, and the inner diameter side of the leaf spring elastically deforms around the annular abutment portion, thereby preventing excessive deformation of the flexible part. A gap is provided on the inner diameter side of the annular abutment portion formed at the annular protrusion with a trapezoidal cross-section, thereby ensuring the width of the gap and preventing contact between the spring component and the seat ring when the spring component deforms. As a result, the rapid increase in reaction force from the spring component is suppressed, preventing the flexible part, which tilts due to the disc, from being clamped between the fixed side and the seat ring along with the leaf spring, effectively preventing plastic deformation of the flexible part.

[0036] According to the invention of technical solution 5, when a force is applied to the leaf spring from the flexible part, the leaf spring can be deformed by collapsing on the inner diameter side with the annular abutment part as the fulcrum, thereby generating a predetermined elastic force. The tilting of the leaf spring stops, preventing the plastic deformation of the seat ring caused by the rapid increase of the reaction force.

[0037] According to the invention of technical solution 6, the gasket portion is formed independently of the flexible portion and the fixed portion via a thin-walled portion on the outer periphery of the fixed portion, and the gasket portion is sandwiched between the valve body and the seat ring, thereby preventing internal leakage from the valve body and the seat ring. In this case, even if the gasket portion undergoes thermal expansion at high temperatures, the sealing performance between the valve body and the seat ring is maintained when the fluid returns to normal temperature. By providing the thin-walled portion, the deformation caused by the thermal expansion of the gasket portion will not adversely affect the fixed portion and the flexible portion, thus maintaining stable valve seat sealing performance even under high-temperature fluid conditions caused by deformation of the flexible portion.

[0038] According to the invention of technical solution 7, the tightening force generated by the fastening of the locking bolt alone can ensure a tight seal between the seat ring and the disc when the valve is closed, without the need to connect other components such as the flange tube to push the seat ring towards the valve body. Thus, even when the mounting side of the seat ring is located at the end of the flow path, excellent sealing performance can be maintained to prevent leakage under high back pressure. Therefore, when an excessive back pressure head is applied to a part of the piping in a high-rise building, the seat ring pushing force is suppressed to a low level by balancing the displacement of the disc with the elasticity of the spring component, preventing the seat ring from being pushed towards the seat ring side, preventing sealing leakage, and preventing a drop in the sealing surface pressure at the base of the seat ring, effectively preventing internal leakage. Attached Figure Description

[0039] Figure 1 This is a longitudinal sectional view showing one embodiment of the eccentric butterfly valve of the present invention.

[0040] Figure 2 yes Figure 1 Enlarged schematic diagram of the main parts.

[0041] Figure 3 This is an enlarged schematic diagram showing the key part near the flexible part.

[0042] Figure 4 It means to Figure 3 Enlarged schematic diagram of the main part under positive pressure.

[0043] Figure 5 It means to Figure 3 Enlarged schematic diagram of the main part under the state of applying reverse pressure.

[0044] Figure 6 It is a graph showing the relationship between the deformation of a leaf spring and the spring load.

[0045] Figure 7 It means to Figure 1 An enlarged schematic diagram of the main part of an eccentric butterfly valve under reverse pressure.

[0046] Figure 8 This is a magnified view of a portion of the seat ring assembly area of ​​a conventional double-eccentric butterfly valve.

[0047] Figure 9 This is a schematic diagram illustrating an example of a centralized air conditioning system. Detailed Implementation

[0048] Hereinafter, embodiments of the eccentric butterfly valve of the present invention will be described based on the accompanying drawings. Figure 1 This indicates one embodiment of the eccentric butterfly valve of the present invention. Figure 2 China indicates Figure 1An enlarged schematic diagram of the key parts near the seat ring assembly. The eccentric butterfly valve of the present invention (hereinafter referred to as valve body 20) is designed to have a positive and reverse pressure of approximately 5 MPa.

[0049] Figure 1 In the figure, the valve body 20, for example, is designed with a diameter of 300A, and includes a cylindrical valve body 21, valve stem 22, disc 23, seat ring 24, seat ring 25, and spring component 26. The valve body 21, disc 23, and seat ring 25 are formed from metal materials such as stainless steel and cast steel. In the figure, the left side of the valve body 20 represents the upstream side, and the right side represents the downstream side, corresponding to the fluid pressure (positive pressure) generated when the fluid flows from the upstream side to the downstream side (forward flow) or the fluid pressure (reverse pressure) generated when the fluid flows from the downstream side to the upstream side (backward flow). The seat ring 24 is flexible to the right or left to prevent fluid leakage when the valve is closed. Figure 2 , Figure 3 The upper part of the disc 23 of the valve body 20 is indicated by the lower side, the inner diameter side of the valve body 20 is indicated by the lower side, and the outer diameter side is indicated by the upper side.

[0050] like Figure 1 As shown, the valve body 21 has shaft-mounted portions 30 for assembling the valve stem 22 at its upper and lower parts. The disc 23 is axially supported in an eccentric position within the valve body 21 via the valve stem 22 mounted on these shaft-mounted portions 30. The disc 23 is configured to seal relative to the seat ring 24 fixed within the valve body 21 by the seat ring 25 when the valve is closed.

[0051] The disc 23 is formed in a generally circular plate shape, and a valve body sealing surface 31 is provided on its outer periphery to abut and seal with the seat ring 24. A boss 32 protrudes from the upper and lower parts of one side of the disc 23, and a hole 33 for mounting the valve stem 22 is formed eccentrically from the sealing position in this boss 32. With the valve stem 22 inserted into the hole 33, the disc 23 is integrally fixed to the valve stem 22 at an eccentric position within the valve body 21 by means of a tapered pin 34 and is rotatably supported by a shaft. Thus, the valve body 20 in this example is a double-eccentric type valve in which the valve stem 22 is eccentric relative to the disc 23, and the rotation center of the disc 23 is eccentric from the center of the valve orifice diameter.

[0052] Figure 2 , Figure 3 In this embodiment, the seat ring 24 is formed into a ring shape from a resin material such as PTFE (polytetrafluoroethylene). PTFE with a filler material is used in this embodiment. The seat ring 24 has an annular base portion 40, a flexible portion 41, a fixing portion 42, and a washer portion 43. Furthermore, Figure 2 This indicates the state of the assembled valve body 20, with no fluid pressure applied.

[0053] The base portion 40 is configured with a generally rectangular cross-section, serving as the base of the seat ring 24. On one side of the base portion 40, a flexible portion 41 is integrally formed on its inner diameter side, and a fixing portion 42 is integrally formed on its outer diameter side. On the inner circumferential surface of the base portion 40, a gently sloping surface is continuously formed from the sealing contact portion 45 (described later) of the flexible portion 41. The sloping surface can be straight or curved, or it can be recessed, configured in a suitable shape to provide flexibility when the disc 23 abuts against the flexible portion 41.

[0054] The flexible portion 41 has a predetermined wall thickness on the inner diameter side of the base portion 40, and a sealing contact portion 45 is provided on the side that abuts against the disk 23. The sealing contact portion 45 is located at the bottom of the space portion 46 provided between the fixed portion 42 and the flexible portion 41, near the seat ring 25, and is formed in an annular shape with a predetermined sealing width by means of the shape of the cross-section C surface or the cross-section R surface. With the help of this sealing width, it can be sealed by contacting the surface of the disk 23.

[0055] On the side of the flexible portion 41 opposite to the spring member 26, an annular abutment surface 50 is formed to abut against the spring member 26. The annular abutment surface 50 is configured as a conical surface that is gently inclined at a predetermined inclination angle θ from the vertical direction to the outer diameter direction. The size of the inclination angle θ can be arbitrarily set. When the inclination angle θ is small, the spring force characteristics of the leaf spring 26 can be changed by slightly tilting the flexible portion 41; when it is large, the spring force characteristics cannot be changed unless the flexible portion 41 is tilted more significantly.

[0056] Multiple radially penetrating slits 50a are provided on the annular abutment surface 50. By providing these slits 50a, the annular abutment surface 50 contacts the leaf spring 26 and also guides the positively pressurized fluid into the space 46, ensuring a tight seal between the seat ring 24 and the disc 23, thus achieving a valve seat seal. In this embodiment, the slits 50a are provided at two locations at 180° intervals relative to the annular abutment surface 50, but the number of slits 50a can be set as needed, depending on the size of the valve body 20's diameter.

[0057] The aforementioned space 46, which is grooved on the outer diameter side of the flexible part 41, moves or flexes in the horizontal or inclined direction relative to the flow path direction due to positive or reverse pressure. Thus, when the flexible part 41 is displaced in the flow path direction, it can flex through the space 46 and tilt in the flow path direction in accordance with the magnitude of the displacement. As a result, the sealing contact part 45 abuts and seals with the valve body sealing surface 31.

[0058] On the outer diameter side of the flexible portion 41, a fixing portion 42 is formed with respect to the space portion 46. This fixing portion 42 is fixed between the valve body 21 and the seat ring 25, thereby ensuring that the seat ring 24 is assembled to the valve body 20 in an anti-dislodgement state. The fixing portion 42 is not limited to this shape as long as it does not hinder the flexible portion 41 from flexing in the left-right direction (flow path direction). In this example, it is provided with a rectangular cross-section.

[0059] A thin-walled portion 51 is formed around the outer peripheral surface of the fixing portion 42 in an annular shape, and a hook-shaped washer portion 43 is integrally formed on the fixing portion 42 continuously with the thin-walled portion 51. The washer portion 43 is fitted into the mounting groove 52 formed in the seat ring 25 in a tight-fitting state, and is sandwiched between the seat ring 25 and the valve body 21 in this state, thereby preventing internal leakage of fluid from between them. The thin-walled portion 51 is provided, for example, with a thickness of about 1 to 1.5 mm, thereby suppressing the outflow of excess fluid caused by thermal expansion, even in the event of thermal expansion.

[0060] The spring component 26 is composed of a ring-shaped and flat leaf spring, with an outer diameter that allows it to be assembled between the seat ring 24 and the seat ring 25, and is configured to be assembled in a state where they spring back to each other. The leaf spring 26 is configured such that its outer diameter side abuts against the opposite side of the seat ring 25, and on the opposite side of the seat ring 24, it abuts against the flexible portion 41 on the inner diameter side, closer to the abutment position than the seat ring 25 side. When the flexible portion 41 flexes and is about to tip over, the annular abutment surface 50 abuts against the leaf spring 26, thereby causing the leaf spring 26 to elastically deform from the inner diameter side. As the amount of tipping of the flexible portion 41 increases, the abutment position against the seat ring 24 gradually shifts from the inner diameter side to the outer diameter side.

[0061] In addition, the leaf spring 26 is made of stainless steel, and the thickness of the thin-walled portion 51 is 1.35 mm when the nominal diameter B is 2 1 / 2 to 4, 1.45 mm when the nominal diameter B is 5 to 8, and 1.7 mm when the nominal diameter B is 10 to 12.

[0062] By providing leaf spring 26, the disc 23 is displaced towards the seat ring 25 due to fluid pressure (reverse pressure). When the flexible part 41 tilts due to this displacement, the spring load in the return direction of leaf spring 26 increases in a manner approximately proportional to the magnitude of the tilt. In this case, leaf spring 26 deforms such that its inner diameter side tilts more as the flexible part 41 tilts.

[0063] The seat ring 25 is formed in a generally annular shape, and the aforementioned leaf spring 26 is arranged near its outer diameter side, so that the seat ring 24 can be temporarily installed with the leaf spring 26 in between. Thus, the seat ring 25, leaf spring 26, and seat ring 24 can be assembled to the valve body 21 in an integrated state. At the seat ring 25, on the mounting surface side of the spring member 26 and seat ring 24, annular gaps 53, annular protrusions 54, annular abutments 55, annular convexities 56, annular grooves 57, annular protrusions 58, and annular recesses 52 are respectively provided from its inner diameter side, and are formed in a concave-convex shape by means of them.

[0064] The annular protrusion 54 is formed in a trapezoidal cross-section at the assembly position of the leaf spring 26, allowing it to abut against the leaf spring 26. An annular abutment portion 55 is provided at a position on the outer diameter of the annular protrusion 54, allowing the leaf spring 26 to abut against the annular abutment portion 55 in a line contact state. Thus, the leaf spring 26 elastically deforms by using the abutment portion abutting against the annular abutment portion 55 as a fulcrum, tilting its inner diameter laterally towards the flow path direction.

[0065] The gap 53 is formed on the inner diameter side of the annular abutment portion 55, and can accommodate the tilted portion of the inner diameter side of the leaf spring 26 that is deformed by the push of the elastically deformable flexible portion 41. The size of the gap 53 can be arbitrarily set by adjusting the height and width of the aforementioned annular protrusion 54, and is a space that does not contact the inner diameter end side of the deformed leaf spring 26 with the seat ring 25.

[0066] Here, in Figure 6 In the diagram shown, the dashed line represents the imaginary line at the valve body 20, with the inflection point O as the origin, where the leaf spring 26 contacts the seat ring 25. At this point, the increase in spring load relative to the deformation of the leaf spring rises sharply, potentially causing excessive force to be applied to the seat ring 25, leading to plastic deformation of the seat ring 24. Therefore, by providing the gap 53, contact between the tilted portion of the leaf spring 26 and the seat ring 25 is prevented, and the flexible portion 41 is not clamped between the disc 23 and the seat ring 25, thus preventing plastic deformation of the flexible portion 41.

[0067] Figure 3 In the aforementioned state where the leaf spring 26 and the annular abutment portion 55 are in contact, when force is applied to the leaf spring 26 from the flexible portion 41, the force is applied relative to the leaf spring 26 with the annular abutment portion 55 as the fulcrum. In this case, the outer diameter end of the annular abutment surface 50 (position of point P2) is positioned on the inner diameter side relative to the normal H of the leaf spring 26 at the contact position between the annular abutment portion 55 and the leaf spring 26.

[0068] Figure 2In this design, an annular protrusion 56 is formed opposite to the space 46 of the seat ring 24 on the outer diameter side of the annular protrusion 54. It is configured with a length shorter than the depth of the space 46 and a thickness thinner near the annular groove 57 compared to the width of the space 46. The annular groove 57 is formed at the opposite position of the fixing portion 42 of the seat ring 24, with a depth and width sufficient to fix the annular protrusion 56 by inserting the fixing portion 42 on the outer diameter side. The annular protrusion 58 is formed at the opposite position of the thin-walled portion 51, with a length and thickness sufficient to accommodate the annular insertion space 59 provided between the fixing portion 42 and the washer portion 43. The mounting groove 52 is formed at the opposite position of the washer portion 43, with a depth and width sufficient to accommodate the washer portion 43 for a tight seal.

[0069] Seat ring 24 is assembled to seat ring 25 with leaf spring 26 in between. At this time, the annular protrusion 56, annular groove 57, annular protrusion 58, and mounting groove 52 of seat ring 25 are respectively positioned opposite the space portion 46, fixing portion 42, thin-walled portion 51, and washer portion 43 of seat ring 24, and are respectively inserted. After seat ring 24 and seat ring 25 are installed, fixing portion 42 is fixed in the annular groove 57 in the fitted state, thereby positioning fixing portion 42. Therefore, flexible portion 41 is positioned in a predetermined radial direction.

[0070] With the seat ring 24 positioned between the valve body 21 and the seat ring 25 as described above, they are integrally fixed by a locking bolt 60. In this case, the valve body 21 and the seat ring 25 are fixed in a surface contact state based on so-called metal-to-metal contact. The locking bolt 60 has a predetermined tightening force, and after tightening, the valve body 20 does not require external tightening force when the valve is closed, and the sealing state between the seat ring 24 and the disc 23 is maintained.

[0071] With the tightening force of the stop bolt 60, when the valve is closed, the sealing contact part 45 pushes the disc 23, and the flexible part 41 tilts slightly towards the seat ring 25, so that the inner diameter side of the leaf spring 26 is also slightly pushed towards the seat ring 25. In this state, two forces are generated: the reaction force of the leaf spring 26 due to the tilting of the flexible part 41 and the force based on the warping of the seat ring 24 itself. Due to these forces, the sealing surface pressure between the disc 23 and the seat ring 24 is generated.

[0072] Furthermore, the shape and function of the base portion 40, flexible portion 41, and fixing portion 42 of the seat ring 24 are not strictly limited. That is, when the flexible portion 41 bends and tilts, not only the flexible portion 41 but also a part of the base portion 40 is flexible. When the flexible portion 41 moves due to thermal changes, the movement is mitigated by the fixing portion 42. Thus, for example, the fixing portion 42 also has a function other than fixing the seat ring 24. In addition, for example, the washer portion 43 is not limited to the function of preventing internal leakage, but also has the function of fixing the seat ring 24.

[0073] In each part of the fixing part 42 and the washer part 43, a predetermined volume of crush allowance can be set as needed. In this case, the crush allowance is pushed and the surface pressure is increased, thereby improving the sealing performance between the washer and the seat ring 25 and enhancing the leakage prevention function.

[0074] Next, using Figure 6 The diagrams, together with the principle of applying pressure to the seat ring 24, illustrate the operation and function of the above-described embodiment of the eccentric butterfly valve of the present invention. Figure 6 In the figure, represents the relationship between the amount of deformation when pressure is applied to the leaf spring 26 and the spring load generated corresponding to that deformation.

[0075] In the diagram, the origin O of the load characteristic change of leaf spring 26 when positive or negative pressure is applied to the valve is defined as the inflection point. O represents the no-load state when no fluid pressure is applied to the valve; at this point, the spring load of leaf spring 26 is as shown by load F. O The size is shown. Taking the origin O as the boundary, the load characteristics caused by the reaction force of the leaf spring 26 applied to the seat ring 25 are different under the positive pressure state and the reverse pressure state. Taking the position of the origin O as the reference, the state when positive pressure is applied is set to the left of the origin O, and the state when reverse pressure is applied is set to the right.

[0076] In the open state (not shown) of the valve body 20, the seat ring 24 hardly tilts, and the force exerted on the seat ring 24 by the leaf spring 26 is minimal. When the valve body 20 begins to close from this state, the disc 23 pushes the seat ring 24, causing the leaf spring 26 to tilt. As a result, the reaction force of the leaf spring 26 acts on the side of the seat ring 24.

[0077] Spring component 26 in Figure 2 In the assembled state, it is configured to apply a slightly weaker spring-back force to the flexible part 41. The spring-back force F in this case is as follows: Figure 6 Spring load F O As shown, it is set to about 20-30% of the maximum rebound force of the spring component 26.

[0078] When the valve body 20 is in the fully open state under positive pressure, the spring member 26 also applies a restoring force to the flexible part 41. However, the restoring force in this case is determined by the degree of contact between the spring member 26 and the flexible part 41, such as... Figure 6 The spring load F at point B B As shown, the spring component 26 is set to 5-10% of the maximum rebound force.

[0079] Thus, in this invention, the spring member 26 is always in contact with the flexible portion 41. Consequently, corresponding to the tilting of the flexible portion 41, the spring member 26 follows the movement of the flexible portion 41 under either positive or negative pressure, resulting in good responsiveness.

[0080] Figures 1-3 In this case, the valve body 20 is in the closed state, indicating a no-load state where no fluid pressure is applied to the valve body 20, i.e., the fluid pressure to the valve body 20 at the origin O is 0 MPa. In this state, the valve body sealing surface 31 of the disc 23 pushes the sealing contact portion 45 of the flexible portion 41 to the left, and the seat ring 24 deforms by tilting the flexible portion 41 slightly to the left while the fixed portion 42 is fixedly held between the valve body 21 and the seat ring 25. At this time, a force based on the elasticity of the leaf spring 26 is applied from the flexible portion 41, and the spring load of the leaf spring 26 during deformation is applied to the flexible portion 41.

[0081] In this state at the origin O, the flexible part 41, by means of its own flexibility and the elastic force of the leaf spring 26 in the direction of the disc 23, causes the sealing contact part 45 to come into close contact with the valve body sealing surface 31 with a predetermined sealing surface pressure, thereby achieving a solid seal.

[0082] On the opposite side of the flexible portion 41 and the leaf spring 26, a generally conical annular abutment surface 50 inclined at a predetermined angle θ in the outer diameter direction is provided. Therefore, in the state where the inner diameter side of the flexible portion 41 is closer to the leaf spring 26, in the unloaded state of this embodiment, such as Figure 3 As shown, the flexible portion 41 abuts against the leaf spring 26 in the range from point P1 on the inner diameter side to point P2 on the outer diameter side. Thus, in the assembled state, i.e., the unloaded state without the application of fluid, the annular contact surface 50 of the flexible portion 41 contacts the leaf spring 26 in the range from point P1 to point P2.

[0083] When positive and negative pressure are applied to the valve body 20 in this state, the spring load changes accordingly to (1) the case of applying positive and negative pressure relative to the leaf spring 26, and (2) the case of different inclination angles θ relative to the annular contact surface 50 of the leaf spring 26. Therefore, these (1) and (2) are studied respectively.

[0084] (1) Regarding the application of positive or negative pressure to the leaf spring 26, when positive or negative pressure is applied to the valve body 20, the seat ring 24 collapses due to the fluid pressure. The contact position with the leaf spring 26 changes depending on the degree of collapse of the seat ring 24. Therefore, the load characteristics of the reaction force of the leaf spring 26 applied to the seat ring 24 are as follows: Figure 6 The solid line shows the variation, due to the load characteristics of a leaf spring 26 producing two spring coefficients.

[0085] Under positive pressure, the collapse of the seat ring 24 is reduced. In this case, such as Figure 4 As shown, at point P1 of the annular contact surface 50, the contact surface 26a of the leaf spring 26 comes into contact with the leaf spring 26, and the load applied by the leaf spring 26 to the seat ring 24 becomes relatively small.

[0086] Under positive pressure, the collapse of the seat ring 24 decreases, and the annular contact surface 50 of the flexible part 41 makes approximately linear contact with the point P1 on the inner circumferential side of the leaf spring 26. This state is... Figure 6 The state near α, the spring load applied from leaf spring 26 to seat ring 24 is greater than the spring load F at origin O. O Small.

[0087] On the other hand, under reverse pressure, such as Figure 5 As shown, the collapse of the seat ring 24 increases. In this case, point P2 of the annular contact surface 50 contacts the leaf spring 26, and the load applied by the leaf spring 26 to the seat ring 24 increases.

[0088] Under reverse pressure, the collapse of the seat ring 24 increases, and the annular contact surface 50 of the flexible part 41 makes approximately linear contact with the point P2 on the outer periphery of the leaf spring 26. This state is... Figure 6 The state near β, the spring load applied from leaf spring 26 to seat ring 24 is greater than the spring load F at origin O. O big.

[0089] Thus, it has the following characteristics: when pressure is applied relative to a specific leaf spring 26, the spring load changes slowly in the positive pressure region and changes drastically compared to the positive pressure region in the reverse pressure region.

[0090] If we describe in detail the application of positive and reverse pressure to the valve body 20, then under the condition of applying reverse pressure, such as Figure 5 As shown, the disk 23 displaces, causing the flexible part 41 to tilt further. The contact position between the flexible part 41 and the leaf spring 26 gradually shifts towards point P2 on the outer diameter. If further reverse pressure is applied, the load on the leaf spring 26 increases while point P2 is in line contact. Thus, when fluid pressure is applied to the seat ring 24, the seat ring 24 gradually tilts, and the contact position with the leaf spring 26 changes accordingly to the magnitude of this tilt.

[0091] Line contact is made at point P2, thereby keeping the distance W (in this embodiment, radial distance) between the annular abutment portion 55 and point P2 constant. Therefore, the torque represented by the product of the distance W and the spring load F of the leaf spring 26 can be stably obtained, and the sealing performance between the sealing connection portion 45 of the flexible portion 41 and the disc 23 can be reliably ensured.

[0092] At this time, the leaf spring 26 abuts against the outer diameter side of the opposite side of the seat ring 25 and against the inner diameter side of the opposite side of the seat ring 24, so the leaf spring 26 elastically deforms on the inner diameter side with the annular abutment part 55 of the seat ring 25 as the fulcrum.

[0093] On the other hand, when a positive pressure in the direction of the arrow is applied to the valve body 20 in the closed state, such as Figure 4 As shown, the valve seat can be sealed under low pressure by means of the sealing surface pressure generated by the warping of the seat ring 24 and leaf spring 26 during assembly.

[0094] In this situation, the disc 23 moves downstream (to the right) due to fluid pressure, while the flexible part 41 maintains a tight contact with the disc 23 and tilts downstream. This maintains the seal between the sealing contact part 45 and the valve body sealing surface 31. As they move downstream, the spring load F based on the leaf spring 26 also decreases. Furthermore, in Figure 6 On the positive pressure side, as the positive pressure increases, the elastic deformation of the leaf spring 26 decreases, and thus the spring load also decreases further. Near the maximum fluid pressure, the load on the leaf spring 26 is extremely small.

[0095] In this way, when the flexible part 41 tilts less, it is in a state where the leaf spring 26 contacts the point P1 on the inner diameter side of the annular contact surface 50, and the load applied to the flexible part 41 by the leaf spring 26 is less.

[0096] If the deflection of the disc 23 and the warping of the valve stem 22 increase with the increase of fluid pressure, the disc 23 moves towards the valve stem 22 side on the secondary side, and the sealing surface pressure decreases. Consequently, the warping of the leaf spring 26, which is in a slightly tilted state during assembly, decreases due to the movement of the disc 23. Thus, the spring load exerted by the leaf spring 26 on the flexible part 41 also decreases. However, the flexible part 41, subjected to fluid pressure, collapses towards the disc 23 side, and the sealing contact part 45 pushes against the disc 23, thereby achieving a self-sealing function by means of the seat ring 24, and the valve seat sealing performance is maintained.

[0097] When setting the tilt angle θ of the annular contact surface 50, considering the operation of the seat ring 24 under reverse and positive pressure conditions, the tilt angle θ is set to 12° in small-diameter valves (e.g., nominal diameter 65A to 80A), while in large-diameter valves (e.g., nominal diameter 200A to 300A), the tilt angle θ is set to 4°. This is because the movement of the disc 23 in small-diameter valves is small, while the movement (rotational motion) of the flexible part 41 needs to be large, hence the tilt angle θ is set larger than that in large-diameter valves.

[0098] Here, during the aforementioned reverse pressure, the disc 23, seat ring 24, and leaf spring 26 are to be transformed into... Figure 7 The state indicated by the double-dotted line. At this time, as... Figure 3 As shown, the flexible part 41 tilts in the direction of the arrow.

[0099] Due to fluid pressure, warping occurs at disc 23 and valve stem 22. As disc 23 moves upstream towards seat ring 24 (to the left), seat ring 24 is pushed towards seat ring 25, and the inner diameter side of leaf spring 26 also tends to tilt. As the fluid pressure rises to high pressure, the amount of movement of disc 23 also increases, and the tilting of the flexible portion 41 of seat ring 24 and leaf spring 26 also increases significantly. The tilting of flexible portion 41 also affects the reverse pressure applied to seat ring 24, causing leaf spring 26 to tilt. Thus, a spring force is applied in the direction that aims to restore the flexible portion 41 from the collapsed leaf spring 26 to its original state, ensuring a tight seal.

[0100] Specifically, Figure 3 When the flexible part 41 is tilted in the direction of the arrow, the annular contact surface 50 abuts against the leaf spring 26 in the range from point P1 to point P2. At this time, under positive pressure, the contact is approximately at point P1, and the force applied to the flexible part 41 has a low load characteristic. However, under reverse pressure, the contact is between point P1 and point P2, generating a load with a high load characteristic. The flexible part 41 tilts between point P1 and point P2 in a state of abutment against the leaf spring 26, corresponding to the position of the reverse / positive pressure disc, and a spring load corresponding to the tilting amount is applied to the flexible part 41.

[0101] Specifically, when reverse pressure is applied, leaf spring 26 contacts at point P2, increasing the spring load from leaf spring 26. However, it maintains seat ring 24 under a state of appropriate sealing surface pressure balance, thus preventing excessive deformation of flexible portion 41. Therefore, even under large reverse pressure, plastic deformation, wear, and breakage of seat ring 24 are prevented, maintaining sealing performance and ensuring the sealing surface pressure between seat ring 24 and disc 23, effectively preventing seal leakage.

[0102] In the diagram, if the distance from point P1 (the point of contact between the flexible portion 41 and the leaf spring 26 at its minimum deformation) to the annular abutment portion 55 is defined as distance L1, and the distance from point P2 (the point of contact between the flexible portion 41 and the leaf spring 26 at its maximum deformation) to the annular abutment portion 55 is defined as distance L2, then distance L1 > distance L2. Therefore, due to the change in fluid pressure towards the disc 23, the tilting amount of the flexible portion 41 increases, and consequently, the distance from the annular abutment portion 55 to the position where the force is applied decreases. Thus, as... Figure 6 As shown, as the flexible part 41 tilts more under reverse pressure, the load on the leaf spring 26 also increases approximately proportionally. Even when excessive reverse pressure is applied to the disc 23, the tilting of the flexible part 41 can be suppressed, and the sealing surface pressure with the disc 23 can be increased.

[0103] Next, the case where the inclination angle θ of the annular contact surface 50 is different relative to (2) leaf spring 26 will be explained.

[0104] By changing the tilt angle θ, the timing (position of the inflection point) at which the load characteristics of the leaf spring 26 relative to the flow direction of the fluid can be changed in a valve body 20 of the same size.

[0105] For example, if the inflection point is set at the origin O1, then as follows Figure 6 As shown by the single-dotted line, it can exert high load characteristics earlier from the positive pressure side, corresponding to the fluid pressure.

[0106] Therefore, by arbitrarily setting the inflection point of the tilt angle θ forming the spring component 26, a valve with desired characteristics can be obtained by using it in the positive pressure region with low load characteristics before the inflection point and in the negative pressure region with high load characteristics after the inflection point. If the tilt angle θ of the annular contact surface 50 is set to a large value, it is suitable for small-diameter valves with small movement of the disc 23. On the other hand, if the tilt angle θ is set to a small value, the spring 26 can be made to rebound when a large negative pressure is applied to the flexible part 41, which is suitable for large-diameter valves with large movement of the disc 23.

[0107] This allows for the provision of a valve, which, based on the magnitude of the inclination angle θ of the annular contact surface 50, will... Figure 6 The inflection point (origin O) on the chart can be set at any position to provide appropriate sealing performance corresponding to the difference in caliber from small to large.

[0108] As described above, the valve body 20 of the present invention forms a flexible portion 41 on the inner diameter side of the seat ring 24. A leaf spring 26 is assembled between the flexible portion 41 and the seat ring 25. The spring load of the leaf spring 26 changes in accordance with the tilting size of the flexible portion 41 based on the displacement of the disc 23. Therefore, for example, when a high-pressure fluid of about 5 MPa positive pressure to about 5 MPa reverse pressure is applied to the disc 23, leakage can be effectively prevented while maintaining a high level of sealing performance when the valve is closed, taking into account both positive and reverse pressure. At this time, the spring load increases or decreases in accordance with the magnitude of the fluid pressure, thereby suppressing excessive sealing surface pressure of the valve under high reverse pressure, thus improving operability.

[0109] A gap 53 is provided on the inner diameter side of the annular abutment portion 55, so that even if excessive force is applied to the inner diameter side of the leaf spring 26 due to the tilting of the flexible portion 41 based on the reverse pressure, it will not be as... Figure 3 As shown by the double-dotted line, the tilting portion deforms in a manner that escapes towards the gap 53, thereby preventing the inner diameter of the leaf spring 26 from contacting the seat ring 25. Therefore, the deformable flexible portion 41 will not be clamped between the seat ring 25, the leaf spring 26, and the disc 23. Figure 6 The change in the amount of deformation of the leaf spring 26 under reverse pressure is maintained in a roughly proportional manner, thereby preventing plastic deformation of the flexible part 41 without a sharp increase in the pressure on the sealing surface.

[0110] like Figure 3 As shown, by positioning the outer diameter end of the annular abutment surface 50 (at point P2) closer to the inner diameter than the normal H, the contact point between the flexible portion 41 and the leaf spring 26 is always located on the inner diameter side compared to the normal H at any point between points P1 and P2. Therefore, when a force is applied to the flexible portion 41 from the disc 23, a clockwise force is always applied to the contact point between the flexible portion 41 and the leaf spring 26, centered on the annular abutment surface 55. The direction of this force coincides with the direction of deformation on the inner diameter side of the leaf spring 26, thus efficiently transmitting the force from the flexible portion 41 to the leaf spring 26 to utilize the spring load.

[0111] In contrast, if the outer diameter end of the annular abutment surface 50 is positioned on the outer diameter side compared to the normal H, when force is applied to the flexible portion 41 from the disc 23, a counterclockwise rotational force is applied to the contact point between the flexible portion 41 and the leaf spring 26 with the annular abutment portion 55 as the center. This force is in the opposite direction to the deformation direction of the inner diameter side of the leaf spring 26, so the movement of the leaf spring 26 stops, and the force pushing the leaf spring 26 acts on the flexible portion 41, which may cause plastic deformation of the flexible portion 41. Therefore, as mentioned above, it is preferable to position the outer diameter end of the annular abutment surface 50 (the position of point P2) on the inner diameter side compared to the normal H.

[0112] In addition, the leaf spring 26 can be set to switch its spring characteristics (spring constant) at the inflection point in such a way that its spring load decreases in the positive compression region and increases in the negative compression region.

[0113] For this reason, in the positive pressure region, as mentioned above, the self-sealing function utilizing fluid pressure can be utilized. Therefore, even if the seat ring 24 itself experiences fatigue or a decrease in its resilience, a seal can be achieved as long as the spring load provides a minimum sealing surface pressure in the low-pressure region of positive pressure. Furthermore, in the medium- and high-pressure regions, the self-sealing function also increases, thereby achieving sealing performance with almost no spring load required. Therefore, the spring load of the leaf spring 26 under positive pressure is only slightly higher than that generated under low-pressure, no-load conditions.

[0114] On the other hand, in the reverse pressure region, it is necessary to support the flexible part 41 that tilts due to the movement of the disc 23, and the seat ring 24 that tilts due to the fluid pressure, so as to maintain a state in which the load of the leaf spring 26 is balanced with the force acting on them. Therefore, it is set so that the spring load increases as the fluid pressure rises.

[0115] In this embodiment, to satisfy the conditions of the positive pressure region and the negative pressure region described above, an inflection point (origin O) is set as the point where the contact point between the flexible portion 41 and the leaf spring 26 shifts, corresponding to the tilting amount of the flexible portion 41 of the seat ring 24. By setting this inflection point as the boundary, a low-load characteristic with a low increase in spring constant can be provided on the positive pressure region side of the leaf spring 26, and a high-load characteristic with a high increase in spring constant on the negative pressure region side (after the inflection point).

[0116] Compared to the flexible portion 41, the fixing portion 42 is integrally formed on the outer diameter side. A hook-shaped washer portion 43 is integrally formed on the outer peripheral surface of the fixing portion 42 via a thin-walled portion 51. Therefore, the washer portion 43 is fixed independently of the fixing portion 42 and the flexible portion 41 between the valve body 21 and the seat ring 25. Consequently, the outflow of the remaining portion due to thermal expansion during the high temperature of the washer portion 43 in the thermal cycle is suppressed, and the volume is maintained to prevent internal leakage even when the temperature returns to normal.

[0117] During the assembly of the valve body 20, the seat ring 24 and the disc 23 are sealed together, and the valve body 21 and the seat ring 25 are securely fastened together with the stop bolt 60 in a metal-to-metal contact state. After fastening, the seat ring 24 is not further tightened, so the stress on the seat ring 24 caused by the removal of the pipe bolts is relieved, and the stop bolt 60 does not loosen, maintaining the tightness. At this time, by setting the compression ratio and filling ratio of the washer portion 43 into the mounting groove 52 to the necessary minimum, the fastening force generated by the metal-to-metal contact can be further improved.

[0118] Furthermore, by making the plug hole of the stop bolt 60 of the valve body 21 and each surface of the seat ring 25 in contact with the entire surface, the tightening force of the stop bolt 60 can be maintained.

[0119] By fastening the retaining bolt 60, the seat ring 24, which tilts due to fluid pressure, is supported; the seat ring 24 and leaf spring 26, which tilt due to disc 23, are supported; and the surface pressure of the washer portion 43 is maintained to maintain the sealing performance.

[0120] As mentioned above, the sealing of the seat ring 24 relative to the reverse pressure when the valve is closed can be maintained solely by the tightening force of the stop bolt 60. Therefore, even when the valve body 20 is disassembled to the point where the connecting flange on the upstream side is removed, valve seat leakage and internal leakage can be prevented.

[0121] Therefore, for example, it is also possible to... Figure 9 The longitudinal piping 14 of the central air conditioning unit 10 shown uses the valve body 20 of the present invention. In this case, the cooling tower 12 is located on the upper side (high-rise side), and the valve body 20 is installed on the lower side (lower-rise side) of the longitudinal piping 14 on the upstream and downstream sides of the piping 13, so that the valve body 20 is in the open state. Figure 9 (a) The operating state of the central air conditioning equipment 10, or the valve body 20 being in a closed state. Figure 9 (b) The central air conditioning equipment 10 is in a stopped state, in which maintenance can be performed.

[0122] Figure 9 In state (b), during maintenance, the connecting flange 15 and part of the piping 13 on the lower side of the valve body 20 are disassembled, so that the lower side of the valve body 20 is the endpoint, and maintenance and cleaning can be performed on each piping 13 on the upper or lower side compared to the valve body 20.

[0123] In this final state, when the water pressure in the piping 13 exerts a force on the valve body 20 due to gravity, particularly at the valve body 20 on the left side of the figure (the valve with the seat ring 25 positioned at the bottom), the back pressure due to water head pressure becomes excessive as the building becomes taller and the longitudinal piping 14 becomes longer. To counteract this excessive back pressure, leakage is prevented by maintaining the sealing surface pressure between the seat ring and the disc solely through the tightening force of the stop bolt and the reaction force of the leaf spring, and internal leakage from the gasket side is also prevented. This prevents plastic deformation and wear of the seat ring, thereby maintaining the valve seat's sealing performance for a long period.

[0124] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the foregoing embodiments and various changes can be made without departing from the spirit of the invention as described in the claims.

[0125] Explanation of reference numerals in the attached figures

[0126] 20 Valve body

[0127] 21 Valve body

[0128] 22 Valve stem

[0129] 23 discs

[0130] 24 rings

[0131] 25-seat ring

[0132] 26 Leaf Spring (Spring Component)

[0133] 41 Flexible part

[0134] 42 Fixing part

[0135] 43 Washer section

[0136] 50 Annular contact surface

[0137] 51 Thin-walled section

[0138] 53. Void

[0139] 54. Annular protrusion

[0140] 55. Circular abutment part

[0141] 60 stop bolt

[0142] Point P1

[0143] Point P2 (the outer diameter end of the annular contact surface)

[0144] H-normal.

Claims

1. An eccentric butterfly valve, wherein a disc, rotatably supported at an eccentric position within a cylindrical valve body via a valve stem, is sealingly mounted on a seat ring fixed within the valve body by means of a seat ring, characterized in that, A flexible portion that tilts in accordance with the displacement of the aforementioned disc is formed on the inner diameter side of the aforementioned seat ring. An annular leaf spring is assembled between the aforementioned flexible portion and the aforementioned seat ring to spring back the aforementioned flexible portion and the aforementioned seat ring. The aforementioned leaf spring is assembled such that when the aforementioned disc is displaced toward the aforementioned seat ring in the flow path direction, the load in the springback direction increases in accordance with the magnitude of the tilt of the aforementioned flexible portion caused by the displacement of the aforementioned disc. Furthermore, when the outer diameter side abuts against the aforementioned seat ring on the opposite side of the aforementioned seat ring, and the inner diameter side abuts against the aforementioned flexible portion on the opposite side of the aforementioned seat ring, as the tilt of the aforementioned flexible portion increases, the abutment position with the aforementioned seat ring gradually shifts from the inner diameter side to the outer diameter side. When the aforementioned flexible portion elastically deforms, the aforementioned leaf spring, which is pushed by the aforementioned flexible portion, elastically deforms in a state that avoids contact between the aforementioned leaf spring and the aforementioned seat ring on the inner diameter side of the rather than the abutment position on the aforementioned seat ring side.

2. The eccentric butterfly valve as described in claim 1, characterized in that, In the aforementioned flexible portion, an annular contact surface is formed on the opposite side to the aforementioned leaf spring, which abuts against the aforementioned leaf spring. The aforementioned annular contact surface is composed of a conical surface that is inclined at a predetermined angle from the inner diameter side to the outer diameter direction.

3. The eccentric butterfly valve as described in claim 1, characterized in that, In the aforementioned seat ring, an annular protrusion with a trapezoidal cross-section is formed on the side that abuts against the aforementioned leaf spring. At the outer diameter position of the aforementioned annular protrusion, an annular abutment portion is formed that abuts against the aforementioned leaf spring through line contact and becomes the fulcrum when the aforementioned leaf spring undergoes elastic deformation. On the inner diameter side of the aforementioned annular abutment portion, a gap portion is formed to prevent contact with the tipping portion of the aforementioned leaf spring.

4. The eccentric butterfly valve as described in claim 2, characterized in that, In the aforementioned seat ring, an annular protrusion with a trapezoidal cross-section is formed on the side that abuts against the aforementioned leaf spring. At the outer diameter position of the aforementioned annular protrusion, an annular abutment portion is formed that abuts against the aforementioned leaf spring through line contact and becomes the fulcrum when the aforementioned leaf spring undergoes elastic deformation. On the inner diameter side of the aforementioned annular abutment portion, a gap portion is formed to prevent contact with the tipping portion of the aforementioned leaf spring.

5. The eccentric butterfly valve as described in claim 4, characterized in that, The outer diameter end of the aforementioned annular contact surface is positioned on the inner diameter side relative to the normal of the aforementioned leaf spring, at the contact position between the aforementioned annular contact portion and the aforementioned leaf spring.

6. The eccentric butterfly valve as described in any one of claims 1 to 5, characterized in that, On the outer diameter side of the aforementioned flexible portion, a fixing portion is integrally formed and fixed between the aforementioned valve body and the aforementioned seat ring. A washer portion, which is integrally connected to the outer peripheral surface of the aforementioned fixing portion via a thin-walled portion, is sandwiched between the aforementioned valve body and the aforementioned seat ring.

7. The eccentric butterfly valve as described in any one of claims 1 to 5, characterized in that, With the aforementioned seat ring and the aforementioned disc in a sealed state, the aforementioned seat ring is fastened and fixed between the aforementioned valve body and the aforementioned seat ring by a fastening stop bolt.

8. The eccentric butterfly valve as described in claim 6, characterized in that, With the aforementioned seat ring and the aforementioned disc in a sealed state, the aforementioned seat ring is fastened and fixed between the aforementioned valve body and the aforementioned seat ring by a fastening stop bolt.

Images