Inner peripheral sealing structure, valve seat structure, and valve

Abstract

The object of the invention of the present application is to provide an inner peripheral sealing structure, a valve seat structure, and a valve that can reduce the operating torque for closing the valve element. An inner peripheral sealing structure (16) is provided on the seat ring (12) of the butterfly valve (10), bulges from the inner peripheral surface (12i) of the seat ring (12), and the outer peripheral surface (14s) of the valve element (14) for the load fluid pressure abuts thereon. The inner peripheral sealing structure (16) is configured to include the following components: a first sealing surface (18(1)) with which the outer peripheral surface (14s) of the valve element (14) can abut and stop; a locking projection (20) that restricts the rotation of the valve element (14); and a locking sealing surface (18(3)) with which the outer peripheral surface (14s) can abut and stop. The inner peripheral sealing structure (16) is configured such that the first sealing surface (18(1)), the locking sealing surface (18(3)), and the locking projection (20) are arranged in sequence in the direction in which the outer peripheral surface (14s) of the valve element (14) moves due to the rotation of the valve element (14). The inner peripheral sealing structure (16) is configured such that the sealing amount of the locking sealing surface (18(3)) is larger than that of the first sealing surface (18(1)).

Description

Technical Field

[0001] The present invention relates to an inner peripheral seal structure, a valve seat structure, and a valve that constitute a valve such as a butterfly valve. Background Art

[0002] Hitherto, a butterfly valve (valve) has been used to close or open against the flow of a fluid. In Figure 7 , as an example, a butterfly valve 100 is shown. The butterfly valve 100 includes a valve box 102, a seat ring 104, and a valve element 106. The valve box 102 and the seat ring 104 are engaged with each other and combined. The valve element 106 is disposed in a flow path 108 of the seat ring 104. The valve element 106 is configured to rotate about a rotation center C0. The seat ring 104 has a sealing portion (inner peripheral seal structure) 110 having a convex shape for the valve element 106 to abut on the inner periphery 104i.

[0003] For the valve element 106, when the fluid is stopped, the valve element 106 is rotated to the Figure 7 shown shut-off position. For the butterfly valve 100, at the shut-off position, the outer peripheral surface 106s of the valve element 106 formed of a metal such as stainless steel enters the sealing portion 110 of the seat ring 104 formed of an elastic member such as rubber (in Figure 7 , the depth of entry, i.e., the sealing amount, is represented by SW). When the valve element 106 is rotated to the shut-off position to close the valve element 106, an operating torque for overcoming the acting force from the sealing portion 110 and the fluid pressure is required. That is, if SW is deep and the acting force from the sealing portion 110 becomes large, the operating torque becomes large. However, if the operating torque becomes large, the scale of the rotary drive member for rotating the valve element 106 becomes large. In addition, there is a literature related to the rotary drive member of the butterfly valve (see Patent Document 1). However, there is no literature related to the present invention.

[0004] Prior art documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-185047 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] An object of the present invention is to provide an inner peripheral seal structure, a valve seat structure, and a valve capable of reducing the operating torque for closing a valve element.

[0009] Solutions for solving the problems

[0010] The inner peripheral sealing structure of the invention of the present application is provided on the seat ring of the valve, bulges from the inner peripheral surface of the seat ring, and the outer peripheral surface of the valve core for the load fluid pressure abuts against it. It is characterized in that

[0011] This inner peripheral sealing structure includes:

[0012] A first sealing surface, which is concave in shape, and the outer peripheral surface of the valve core can abut against the first sealing surface and stop;

[0013] A locking convex portion, which is used for the valve core to be locked and restricts the rotation of the valve core; and

[0014] A locking sealing surface, when the valve core is locked with the locking convex portion, the outer peripheral surface of the valve core can abut against the locking sealing surface and stop,

[0015] The first sealing surface, the locking sealing surface, and the locking convex portion are arranged in sequence in the direction in which the outer peripheral surface of the valve core moves due to the rotation of the valve core,

[0016] This inner peripheral sealing structure is configured such that the depth at which the outer peripheral surface of the valve core enters the locking sealing surface is greater than the depth at which the outer peripheral surface of the valve core enters the first sealing surface.

[0017] In addition, the inner peripheral sealing structure of the invention of the present application is characterized in that in this inner peripheral sealing structure, the first sealing surface, the locking sealing surface, and the locking convex portion are arranged in sequence in the direction in which the outer peripheral surface of the valve core moves due to the rotation of the valve core.

[0018] In addition, the inner peripheral sealing structure of the invention of the present application is characterized in that in this inner peripheral sealing structure, this inner peripheral sealing structure includes a second sealing surface, which is concave in shape, the outer peripheral surface of the valve core can abut against the second sealing surface and stop, and the second sealing surface is continuous with the first sealing surface,

[0019] The first sealing surface, the second sealing surface, the locking sealing surface, and the locking convex portion are arranged in sequence in the direction in which the outer peripheral surface of the valve core moves due to the rotation of the valve core,

[0020] This inner peripheral sealing structure is configured such that the sealing amount of the second sealing surface is larger than the sealing amount of the first sealing surface,

[0021] This inner peripheral sealing structure is configured such that the sealing amount of the locking sealing surface is larger than the sealing amount of the second sealing surface.

[0022] In addition, the valve seat structure of the invention of the present application is a valve seat structure provided on the seat ring of the valve, and it is characterized in that

[0023] This valve seat structure includes:

[0024] The inner peripheral sealing structure according to the technical solution 1 or 2;

[0025] A valve seat side valve stem hole into which a valve stem constituting the rotation center of the valve element is inserted;

[0026] A valve seat side abutting surface provided around the valve seat side valve stem hole for abutting against a valve element side abutting surface around a valve element side valve stem hole of the valve element;

[0027] A continuous first sealing surface that is continuous with the first sealing surface and extends to the valve seat side abutting surface;

[0028] A continuous locking projection that is continuous with the locking projection and extends to the valve seat side abutting surface; and

[0029] A continuous locking sealing surface that is continuous with the locking sealing surface and extends to the valve seat side abutting surface,

[0030] The continuous first sealing surface, the continuous locking projection, and the continuous locking sealing surface have a shape that is integrally sealed against the side of the valve element connection surface between the outer peripheral surface of the valve element and the valve element side abutting surface when abutting.

[0031] In addition, the valve of the present invention is characterized by including the inner peripheral sealing structure.

[0032] Effects of the invention

[0033] According to the inner peripheral sealing structure of the present invention, a first sealing surface capable of abutting and stopping the outer peripheral surface of the valve element is provided independently of the locking sealing surface capable of abutting and stopping the outer peripheral surface of the valve element. Therefore, the operating torque can be set such that the valve element is stopped not by using the locking sealing surface with a sealing amount larger than that of the first sealing surface, but by using the first sealing surface with a smaller sealing amount and a smaller acting force from the seat ring. Thus, the valve element can be rotated and closed with a smaller operating torque, and the operating torque can be reduced. Therefore, the scale of the rotational drive component for rotating the valve element can be reduced. In addition, in the case of a small fluid pressure, even if the valve element is stopped by using the first sealing surface with a small sealing amount, the sealing performance can be maintained. Thus, although the operating torque for closing the valve element is reduced, the sealing performance can be maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a top view showing the inner peripheral sealing structure of the present invention.

[0035] Figure 2 It is for explaining Figure 1 The top view cross-sectional view of the inner peripheral sealing structure shown, Figure 2The (a) of [Figure] is a view showing the state where the valve element is about to contact the seat ring. Figure 2 The (b) of [Figure] is a view showing the state after the valve element contacts the first sealing surface. Figure 2 The (c) of [Figure] is a view showing the state after the valve element contacts the second sealing surface. Figure 2 The (d) of [Figure] is a view showing the state after the valve element is engaged with the locking projection.

[0036] Figure 3 The (a) of [Figure] is a perspective view showing the valve seat structure of the present invention. Figure 3 The (b) of [Figure] is a perspective view showing the valve element.

[0037] Figure 4 It is a front cross-sectional view showing an example of a valve having the inner peripheral seal structure and the valve seat structure of the present invention.

[0038] Figure 5 It is a view for explaining the effect of the sealing surface having a concave curved surface shape. Figure 5 The (a) of [Figure] is a schematic top view showing the sealing surface of the present invention. Figure 5 The (b) of [Figure] is a schematic top view showing the sealing surface of the prior art. Figure 5 The (c) of [Figure] is a chart comparing the sealing amount of the sealing surface of the present invention with the sealing amount of the sealing surface of the prior art.

[0039] Figure 6 It is a view for explaining the effect of the connecting portion between the inner peripheral seal structure (sealing portion) and the valve seat side contact surface. Figure 6 The (a) of [Figure] is a schematic perspective view showing the connecting portion of the present invention. Figure 6 The (b) of [Figure] is a schematic perspective view showing the connecting portion of the prior art.

[0040] Figure 7 It is a front cross-sectional view showing a conventional valve.

[0041] Figure 8 It is a sectional view taken along line A - A showing another embodiment of the seat ring of the present invention.

[0042] Figure 9 It is for explaining Figure 8 A conceptual diagram showing an example of the method for forming the concave curved surface of the seat ring shown. Detailed Embodiments

[0043] Embodiments of the inner peripheral seal structure, the valve seat structure, and the butterfly valve (valve) of the present invention will be described based on the drawings. In Figures 1 to 4 , reference numeral 16 is the inner peripheral seal structure of the present invention. In Figure 3 and Figure 4 , reference numeral 34 is the valve seat structure of the present invention. InFigure 2 and Figure 4 In Figure 4 , reference numeral 10 is the butterfly valve of the present invention application.

[0044] (Structure)

[0045] As Figure 2 shown, the butterfly valve 10 includes a valve box 114 and a seat ring 12 combined with the valve box 114. The valve box 114 is formed of, for example, aluminum (pure aluminum or aluminum alloy). The valve box 114 may also be formed of a metal other than aluminum. The seat ring 12 is formed of, for example, EPDM (ethylene propylene diene monomer rubber) or NBR (nitrile butadiene rubber), and may also be formed of other rubbers or resins. In addition, the butterfly valve 10 includes: a valve element 14 disposed within the seat ring 12; and two valve stems 22 ( Figure 3 as shown in (b) of Figure 3 .), which are fixed to the upper and lower portions of the valve element 14. The valve element 14 is generally disc-shaped or generally circular plate-shaped. The valve element 14 is formed of, for example, stainless steel. The valve element 14 may also be formed of a metal other than stainless steel. The valve element 14 has valve stem holes 26 on the upper and lower portions for inserting and fixing the valve stems 22 ( Figure 3 as shown in (b) of Figure 3 .). The valve stems 22 are formed of stainless steel and may also be formed of a metal other than stainless steel. The valve stems 22 rotatably penetrate through the valve box 114 and the valve seat side valve stem holes 24 of the seat ring 12 ( Figure 3 as shown in (a) of Figure 3 .). The butterfly valve 10 includes a fixing member 140 ( Figure 4 as shown in Figure 4 .), which is connected to the valve box 114 and fixed to a valve driving portion (not shown) having a rotational driving member. The fixing member 140 is formed of, for example, aluminum and may also be formed of a metal other than aluminum.

[0046] (Inner peripheral sealing structure (sealing portion) 16)

[0047] As Figure 1 shown, the seat ring 12 has an inner peripheral sealing structure 16 that bulges from the inner peripheral surface 12i of the seat ring 12 and abuts against the outer peripheral surface 14s of the valve element 14 that bears the load fluid pressure. As Figure 4As shown, the inner peripheral sealing structure 16 is provided at two positions on the left and right of the seat ring 12 (symmetrical positions with the rotation center C1 as the axis of symmetry) when viewed from the front. The inner peripheral sealing structure 16 includes a first sealing surface 18(1) against which the outer peripheral surface 14s of the valve element 14 can abut and stop, and a second sealing surface 18(2) that abuts and stops against the outer peripheral surface 14s of the valve element 14 and is continuous with the first sealing surface 18(1). The first sealing surface 18(1) and the second sealing surface 18(2) have a concave curved surface shape in order to minimize the sealing amount as much as possible. In addition, the inner peripheral sealing structure 16 includes a locking sealing surface 18(3) that abuts and stops against the outer peripheral surface 14s of the valve element 14 and is continuous with the second sealing surface 18(2), and a locking convex portion 20 that engages with the outer peripheral surface 14s of the valve element 14 and restricts the rotation of the valve element 14. The outer peripheral surface 14s of the valve element 14 is configured to engage with the locking convex portion 20 so that it can abut and stop against the locking sealing surface 18(3). In addition, the inner peripheral sealing structure 16 arranges the first sealing surface 18(1), the second sealing surface 18(2), the locking sealing surface 18(3), and the locking convex portion 20 in sequence in the direction in which the outer peripheral surface 14s of the valve element 14 moves due to the rotation of the valve element 14.

[0048] In the inner peripheral sealing structure 16, it is configured that the depth at which the outer peripheral surface 14s of the valve element 14 enters the locking sealing surface 18(3), that is, the sealing amount, is larger than the sealing amount of the first sealing surface 18(1) (the sealing amount of the first sealing surface 18(1): SW1, the sealing amount of the locking sealing surface: SW3). In addition, it is configured that the sealing amount of the second sealing surface 18(2) is larger than the sealing amount of the first sealing surface 18(1) (the sealing amount of the second sealing surface 18(2): SW2). In addition, it is configured that the sealing amount of the locking sealing surface 18(3) is larger than the sealing amount of the second sealing surface 18(2). That is, the acting force from the seat ring 12 increases in the order of the case of stopping at the first sealing surface 18(1), the case of stopping at the second sealing surface 18(2), and the case of stopping at the locking sealing surface 18(3). Therefore, the operating torque for closing the valve element 14 increases in the order of the case of stopping at the first sealing surface 18(1), the case of stopping at the second sealing surface 18(2), and the case of stopping at the locking sealing surface 18(3).

[0049] (Valve seat structure 34)

[0050] As Figure 3 shown, the seat ring 12 is provided with a valve seat structure 34, and this valve seat structure 34 includes two (left and right in the front view) inner peripheral sealing structures 16. In Figure 3 (a), the single-dot chain line, in addition to indicating the rotation center C1, indicates the center line (valley line) in the case of the sealing surface and the edge line in the case of the convex portion. In addition, in Figure 3In (a) of [description], the dashed line indicates the boundary between the inner peripheral sealing structure 16 and the valve seat connection surface 31 described later. In Figure 3 In (b) of [description], the dashed line indicates the boundary between the outer peripheral surface 14s of the valve element 14 and the valve element connection surface 32 described later, and the double-dashed line indicates the boundary between the valve element connection surface 32 and the valve element side abutment surface 28 described later. The valve seat structure 34 is provided at Figure 4 both the upper side and the lower side of the seat ring 12 in [description].

[0051] As Figure 3 shown in (a) of [description], the valve seat structure 34 includes a valve seat side valve stem hole 24 into which the valve stem 22 forming the rotation center C1 of the valve element 14 is inserted. In addition, the valve seat structure 34 includes a valve seat side abutment surface 30 provided around the valve seat side valve stem hole 24 for abutting against the valve element side abutment surface 28 around the valve element side valve stem hole 26 of the valve element 14. In addition, in Figure 3 the range of the dashed line indicating the valve seat side abutment surface 30 in (a) of [description] is the range for abutting against the valve element side abutment surface 28. In addition, the valve seat structure 34 includes: a continuous first sealing surface 18(1)ex that is continuous with the first sealing surface 18(1) and extends to the valve seat side abutment surface 30; and a continuous second sealing surface 18(2)ex that is continuous with the second sealing surface 18(2) and extends to the valve seat side abutment surface 30. In addition, the valve seat structure 34 includes: a continuous locking sealing surface 18(3)ex that is continuous with the locking sealing surface 18(3) and extends to the valve seat side abutment surface 30; and a continuous locking projection 20ex that is continuous with the locking projection 20 and extends to the valve seat side abutment surface 30. The continuous first sealing surface 18(1)ex, the continuous second sealing surface 18(2)ex, the continuous locking sealing surface 18(3)ex, and the continuous locking projection 20ex have a curved shape that closely fits the entire side edge 32si of the curved shape with respect to the valve element connection surface 32 connecting the outer peripheral surface 14s of the valve element 14 and the valve element side abutment surface 28 when abutting. The sealing amount of the continuous first sealing surface 18(1)ex, the continuous second sealing surface 18(2)ex, and the continuous locking sealing surface 18(3)ex decreases as it goes toward the valve seat side abutment surface 30.

[0052] (Function and effect)

[0053] (Inner peripheral sealing structure 16)

[0054] According to Figure 1 and Figure 2, the functions and effects of the inner peripheral seal structure 16 of the butterfly valve 10 of the present invention will be described below. In the inner peripheral seal structure 16, the operating torque required to close the valve element 14 increases in the order of increasing sealing amount, that is, the first sealing surface 18(1) of SW1 with the smallest sealing amount, the second sealing surface 18(2) with a sealing amount larger than SW2 and smaller than SW3, and the locking sealing surface 18(3) of SW3 with the largest sealing amount. In addition, the greater the fluid pressure, the greater the need to increase the sealing amount. Therefore, for example, the operating torque can be set such that when the fluid pressure is 0.5 MPa, the outer peripheral surface 14s of the valve element 14 stops at the first sealing surface 18(1) to close the valve element 14; when the fluid pressure is 1.0 MPa, the outer peripheral surface 14s of the valve element 14 stops at the second sealing surface 18(2) to close the valve element 14; and when the fluid pressure exceeds 1.0 MPa, the outer peripheral surface 14s of the valve element 14 stops at the locking sealing surface 18(3) to close the valve element 14. When the operating torque is set such that the outer peripheral surface 14s of the valve element 14 stops at the first sealing surface 18(1) to close the valve element 14, the operating torque is the smallest. Therefore, the valve element 14 can be closed with a relatively small operating torque, and the scale of the rotary drive component of the valve element can be reduced. In addition, by bringing the outer peripheral surface 14s of the valve element 14 into contact with the first sealing surface 18(1) of the smaller sealing amount SW1, the high durability of the seat ring 12 and the valve element 14 can be achieved. In this case, the sealing amount SW1 is the smallest, and the fluid pressure received by the valve element 14 is 0.5 Mpa, which is the smallest. Therefore, the sealing performance can be sufficiently maintained. Thus, the valve element 14 can be closed with a relatively small operating torque, and the sealing performance can be maintained.

[0055] In addition, according to the inner peripheral seal structure 16, even when the fluid pressure is 1.0 MPa and the operating torque is set such that the outer peripheral surface 14s of the valve element 14 stops at the second sealing surface 18(2) to close the valve element 14, compared with the case where the operating torque is set such that the outer peripheral surface 14s of the valve element 14 stops at the locking sealing surface 18(3) to close the valve element 14, the valve element 14 can be closed with a relatively small operating torque. In addition, according to the inner peripheral seal structure 16, compared with the case where the outer peripheral surface 14s of the valve element 14 stops at the locking sealing surface 18(3) to close the valve element 14, as a method for closing the valve element 14 with a relatively small operating torque, either the first sealing surface 18(1) or the second sealing surface 18(2) can be selected. In addition, according to the inner peripheral seal structure 16, when the fluid pressure is a high pressure exceeding 1.0 MPa, the locking sealing surface 18(3) can be selected as the position where the outer peripheral surface 14s of the valve element 14 stops to close the valve element 14. In this case, even if a relatively large operating torque is accidentally generated, the valve element 14 is locked and stopped by the locking convex portion 20, and the valve element 14 does not disengage from the locking sealing surface 18(3).

[0056] In addition, when the valve core 14 rotates excessively and is locked with the locking protrusion 20 and stops at the locking sealing surface 18 (3), the sealing amount (the amount by which the valve core 14 flattens the inner peripheral sealing structure 16, that is, the depth to which the valve core 14 enters) is larger, and the sealing performance is improved. However, the operating torque becomes larger accordingly. That is, as long as the valve core 14 is rotated with the set operating torque, the sealing performance can be maintained. In the operation of adjusting the valve core opening, there is no worry that the valve core 14 will go over the sealing part and break free, the adjustment operation becomes better, and the operability is improved. In addition, due to the wear of the inner peripheral sealing structure 16 (in Figure 5 (a) shows the sealing surface 19 after wear and the sealing performance is reduced. Figure 5 As shown by the double-dotted line in (a), by adjusting the valve core 14 to rotate more relative to the shut-off position in the direction of closing the valve core 14 (adjustment of the stopper of the drive unit, etc.), the recovery of the sealing performance can be easily anticipated. Therefore, the product life can be extended. In addition, in the case of the prior art, in order to extend the product life, it is necessary to set the sealing amount to be larger so that the sealing performance can be maintained even if it is worn. For example, as in Figure 5 As shown by the two-dot chain line in (b), the sealing amount needs to be set larger to form a larger sealing surface 113. Therefore, the required operating torque becomes larger.

[0057] Furthermore, according to the inner circumferential sealing structure 16, the first sealing surface 18(1), the second sealing surface 18(2), the locking sealing surface 18(3), and the locking projection 20 are sequentially arranged in the direction in which the outer circumferential surface 14s of the valve core 14 moves due to the rotation of the valve core 14. Therefore, when the operating torque is set so that the valve core 14 stops at the first sealing surface 18(1), the outer circumferential surface 14s of the valve core 14 reliably contacts the first sealing surface 18(1) and stops. In other words, the valve core 14 does not hit the locking projection 20 and stop without the outer circumferential surface 14s reaching the first sealing surface 18(1).

[0058] Here, based on Figure 5 The following describes the effect of the concave shape of the sealing surface. Figure 5 In the figure, the X-axis represents the movement of the outer peripheral surface of the valve core. Figure 5 In (a) and (b), the hatched portion is the portion of the seat ring's sealing portion that is flattened by the valve core. Figure 5 In (c), the Y axis represents the sealing amount. Figure 5 In (c), the solid line represents the change in the sealing amount in the present invention, and the double-dashed line represents the change in the sealing amount in the prior art. Figure 5 In the figure, DL is the cut-off position. Figure 5As shown in (c), in the case of the invention of the present application, the sealing amount gradually increases. In contrast, in the case of the prior art, the sealing amount sharply increases from the 0 point. Therefore, compared with the prior art, the total amount of the flattened sealing portion in the invention of the present application is smaller, and the operating torque required to rotate the valve element to close the valve element is less.

[0059] (Valve seat structure 34)

[0060] Based on Figure 3 , the functions and effects of the valve seat structure 34 of the butterfly valve 10 of the invention of the present application will be described below. As described above, the continuous first sealing surface 18(1)ex, the continuous second sealing surface 18(2)ex, the continuous locking sealing surface 18(3)ex, and the continuous locking convex portion 20ex have a curved shape that integrally fits with the side edge 32si of the curved shape with respect to the valve element connection surface 32 between the outer peripheral surface 14s of the valve element 14 connected and the valve element side abutting surface 28 when abutting. Therefore, in the case where the valve element 14 is set to abut against the first sealing surface 18(1) to close, the side edge 32si of the valve element 14 abuts against the continuous first sealing surface 18(1)ex of the seat ring 12. That is, the entire side edge 32si of the curved shape abuts against the continuous first sealing surface 18(1)ex of the curved shape. At this time, the valve element connection surface 32 abuts against the valve seat connection surface 31. Thereby, the abutting area between the valve element 14 and the seat ring 12 can be expanded to improve the sealing performance. In addition, the side edge 32si of the valve element 14 enters the continuous first sealing surface 18(1)ex with a predetermined sealing amount. Therefore, the sealing performance can be improved. In the case where the valve element 14 is set to abut against the second sealing surface 18(2) to close, and in the case where the valve element 14 is set to abut against the locking sealing surface 18(3) to close, the sealing performance between the vicinity of the side edge 32si of the valve element 14 and the valve seat side abutting surface 30 can be similarly improved. In particular, in the case where it is set to abut against the locking sealing surface 18(3) to close, the entire side edge 32si of the valve element 14 abuts against the continuous locking convex portion 20, so that the abutting area can be further expanded to further improve the sealing performance.

[0061] Next, based on Figure 6 the function and effect of the connecting portion 35 between the inner peripheral sealing structure (sealing portion) 16 and the valve seat side abutting surface 30 in the valve seat structure 34 of the invention of the present application will be described. In Figure 6 (a), the connecting portion 35 is indicated by oblique hatching. In Figure 6 (b), the connecting portion 112 is indicated by oblique hatching. In Figure 6 (a), the sealing line (valve seat) VS is indicated by a double-dot chain line. In Figure 6In (b) thereof, the valve seat ridge line VS is indicated by a double-dashed line. In the valve seat structure 34 of the invention of the present application, both the inner peripheral sealing structure 16 and the valve seat side abutting surface 30 are concave shapes. Therefore, at the connecting portion 35, the shapes of the inner peripheral sealing structure 16 and the valve seat side abutting surface 30 can be smoothly connected. Therefore, at the connecting portion 35, no unnecessary operating torque is required. In contrast, in the prior art, as shown in Figure 6 (b) thereof, the sealing portion 110 is a convex shape, while the valve seat side abutting surface 114 is a concave shape. Therefore, at the connecting portion 112, a switching portion for switching from convex to concave is required. Therefore, in order to smoothly connect the shape of the sealing portion 110 with the shape of the valve seat side abutting surface 114, a shape 112ov with a width larger than the width of the shape 112or theoretically required is needed. As a result, the required operating torque becomes larger. In addition, this switching portion is likely to be a design cause of poor sealing performance. Therefore, in practice, operations such as confirming the sealing performance are required. Therefore, in the case of the prior art, a lot of development man-hours are spent. However, the invention of the present application does not require such operations and realizes easy development.

[0062] In addition, in the seat ring 12 of the invention of the present application, as shown in Figure 8 and Figure 9 , the valve seat portion 300 against which the outer peripheral surface 30S of the valve element 14 abuts may also have a concave curved surface 28CC on the valve element 14 side. In this case, the valve element 14 is configured to rotate clockwise around the rotation center C1 of the valve stem, the outer peripheral surface 30S abuts against the concave curved surface 28CC, and after the sealing amount SW of the outer peripheral surface 30S entering the concave curved surface 28CC gradually increases, it stops at the Figure 8 shown sealing position. The sealing position refers to the position where the rotating valve element 14 completely stops due to the resistance from the valve seat convex portion 28CV. The sealing position is determined by the torque of the valve element 14, the elastic modulus of the seat ring 12, and the size of the valve seat convex portion 28CV. In the case of the valve seat portion 300 shown in Figure 8 , the sealing amount SW of the outer peripheral surface 30S entering the concave curved surface 28CC gradually increases, the rotation speed of the valve element 14 gradually decreases due to the resistance from the concave curved surface 28CC, and it stops at the sealing position in a sufficiently reduced state. Therefore, the valve element 14 can be reliably stopped at the sealing position.

[0063] An example of the method for forming the concave surface 28CC will be described below. Initially, in the CAD screen, draw, for example, the rotation locus circle R1 of the outer peripheral surface of the valve element, and draw a plurality of pitch circles whose radii decrease with a constant pitch relative to the rotation locus circle R1. In addition, draw the straight line ST0 passing through the rotation center C1 and the point where the outer peripheral surface contacts the concave surface at the sealing position, and draw a plurality of pitch lines passing through the rotation center C1 that are rotated counterclockwise relative to the straight line ST0 at a constant angular pitch. Next, select predetermined intersections from the intersections of the rotation locus circle R1 and the pitch circles with the straight line ST0 and the pitch lines that can form the concave surface. Draw a spline curve passing through the selected intersections, and this spline curve becomes the concave surface 28CC.

[0064] According to Figure 9 , an example of the method for forming the concave surface 28CC will be specifically described below. Let the radius of the rotation locus circle R1 centered on the rotation center C1 of the valve element 14 be r1. First, draw the rotation locus circle R1. Next, draw a plurality of circles whose radii decrease with a pitch of dmm (for example, 1 mm) relative to the rotation locus circle R1. That is, draw the pitch circle R2 with a radius of r1 - dmm, the pitch circle R3 with a radius of r1 - 2·dmm, the pitch circle R4 with a radius of r1 - 3·dmm, the pitch circle R5 with a radius of r1 - 4·dmm, and the pitch circle R0 with a radius of r1 - 5·dmm. The order of drawing each circle is not limited.

[0065] When the valve element 14 is in the sealing position, let θ (the rotation angle of the valve element 14) = 0°. Draw the straight line ST0 passing through the rotation center C1 and the point P0 where the outer peripheral surface 30S contacts the concave surface 28CC at the sealing position. Next, draw a plurality of pitch lines passing through the rotation center C1 that are rotated counterclockwise relative to ST0 at a pitch of angle θ1 (for example, 3°). That is, draw the straight line ST0 passing through C1 when θ = 0, the pitch line ST5 when θ = -θ1, the pitch line ST4 when θ = -2·θ1, the pitch line ST3 when θ = -3·θ1, the pitch line ST2 when θ = -4·θ1, and the pitch line ST1 when θ = -5·θ1. The order of drawing each line is not limited.

[0066] The intersection points P5 of the plot ST1 and the rotation locus circle R1, P4 of ST2 and R2, P3 of ST3 and R3, P2 of ST4 and R4, P1 of ST5 and R5, and P0 of ST0 and R0. Next, a spline curve passing through these intersection points P5, etc. is drawn. This spline curve becomes the concave surface 28CC. P5 is the point where the outer peripheral surface 30S of the valve element 14 starts to contact the concave surface 28CC of the seat ring 12. At P5, the seal amount SW0 = 0 mm, at P4, the seal amount SW4 = 1·d mm, at P3, the seal amount SW3 = 2·d mm, at P2, the seal amount SW2 = 3·d mm, at P1, the seal amount SW1 = 4·d mm, and at P0, the seal amount SW0 = 5·d mm. The above has described an example of the method for forming the concave surface 28CC, but the method for forming the concave surface 28CC is not limited.

[0067] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and appropriate changes can be made within the scope of achieving the same functions and effects for implementation. For example, the valve of the present invention is not limited to a butterfly valve, and the type of the valve is not limited. In addition, the butterfly valve of the present invention includes single-eccentric, double-eccentric, and triple-eccentric butterfly valves. In addition, it may also be a structure having only either the first sealing surface 18(1) or the second sealing surface 18(2). In this case, the operating torque is set such that the valve element 14 is closed using either the first sealing surface 18(1) or the second sealing surface 18(2), so that it can be closed with an operating torque smaller than the operating torque for closing using the locking sealing surface 18(3). In addition, a concave surface may be formed by the first sealing surface 18(1), the second sealing surface 18(2), and the locking sealing surface 18(3).

[0068] Explanation of reference numerals

[0069] 10. Butterfly valve (valve); 12. Seat ring; 12i. Inner peripheral surface; 14. Valve element; 14s. Outer peripheral surface; 16. Inner peripheral sealing structure; 18(1). First sealing surface; 18(1)ex. Continuous first sealing surface; 18(2). Second sealing surface; 18(2)ex. Continuous second sealing surface; 18(3). Locking sealing surface; 18(3)ex. Continuous locking sealing surface; 20. Locking convex portion; 20ex. Continuous locking convex portion; 22. Valve stem; 24. Valve seat side valve stem hole; 26. Valve element side valve stem hole; 28. Valve element side abutting surface; 30. Valve seat side abutting surface; 31. Valve seat connection surface; 32. Valve element connection surface; 32si. Side edge; 33. Valve seat side abutting surface; 34. Valve seat structure; C1. Rotation center; SW1, SW2, SW3. Seal amount.

Claims

1. An inner circumferential sealing structure is provided on the seat ring of a valve, bulging from the inner circumferential surface of the seat ring, and the outer circumferential surface of a valve element for load fluid pressure abuts thereon. Among them, this inner circumferential sealing structure includes: a first sealing surface, which is in a concave curved surface shape, and the outer circumferential surface of the valve element can abut against the first sealing surface to stop and be set to a shut-off position; a locking convex portion for locking the valve element to restrict the rotation of the valve element; and a locking sealing surface, when the valve element is locked with the locking convex portion, the outer circumferential surface of the valve element can abut against the locking sealing surface to stop and be set to a shut-off position, this inner circumferential sealing structure is configured such that the depth at which the outer circumferential surface of the valve element enters the locking sealing surface, that is, the sealing amount, is larger than the sealing amount of the first sealing surface, the first sealing surface, the locking sealing surface, and the locking convex portion are arranged in sequence in the direction in which the outer circumferential surface of the valve element moves due to the rotation of the valve element, the operating torque for rotating the outer circumferential surface of the valve element to the shut-off position is configured such that, compared with the case of stopping at the locking sealing surface and setting the locking sealing surface to the shut-off position, the operating torque is smaller in the case of stopping at the first sealing surface and setting the first sealing surface to the shut-off position, this inner circumferential sealing structure is configured to select either the first sealing surface or the locking sealing surface as the sealing surface against which the outer circumferential surface of the valve element abuts to stop and be set to the shut-off position, and set the operating torque in such a way that the outer circumferential surface of the valve element stops at the selected sealing surface.

2. The inner circumferential sealing structure according to claim 1, wherein, this inner circumferential sealing structure includes a second sealing surface, which is in a concave curved surface shape, and the outer circumferential surface of the valve element can abut against the second sealing surface to stop and be set to a shut-off position, and the second sealing surface is continuous with the first sealing surface, the first sealing surface, the second sealing surface, the locking sealing surface, and the locking convex portion are arranged in sequence in the direction in which the outer circumferential surface of the valve element moves due to the rotation of the valve element, this inner circumferential sealing structure is configured such that the sealing amount of the second sealing surface is larger than the sealing amount of the first sealing surface, this inner circumferential sealing structure is configured such that the sealing amount of the locking sealing surface is larger than the sealing amount of the second sealing surface, the operating torque for rotating the outer circumferential surface of the valve element to the shut-off position is configured to increase in the order of the case of stopping at the first sealing surface and setting the first sealing surface to the shut-off position, the case of stopping at the second sealing surface and setting the second sealing surface to the shut-off position, and the case of stopping at the locking sealing surface and setting the locking sealing surface to the shut-off position, this inner circumferential sealing structure is configured to select any one of the first sealing surface, the second sealing surface, and the locking sealing surface as the sealing surface against which the outer circumferential surface of the valve element abuts to stop and be set to the shut-off position, and set the operating torque in such a way that the selected sealing surface becomes the shut-off position.

3. A valve seat structure is provided to the seat ring of a valve, wherein, this valve seat structure includes: the inner circumferential sealing structure according to claim 1 or 2; A valve seat side valve stem hole into which a valve stem constituting the rotation center of the valve element is inserted; A valve seat side abutting surface provided around the valve seat side valve stem hole for abutting against a valve element side abutting surface around a valve element side valve stem hole of the valve element; A continuous first sealing surface that is continuous with the first sealing surface and extends to the valve seat side abutting surface; A continuous locking projection that is continuous with the locking projection and extends to the valve seat side abutting surface; And A continuous locking and sealing surface that is continuous with the locking and sealing surface and extends to the valve seat side abutting surface, The continuous first sealing surface, the continuous locking projection, and the continuous locking and sealing surface have a shape that is integrally sealed against the side of a valve element connection surface between the outer peripheral surface of the valve element connected to the valve element and the valve element side abutting surface when abutting.

4. A valve comprising the inner peripheral sealing structure according to claim 1 and a rotary drive member for rotating the valve element, wherein, The rotary drive member is configured to select either the first sealing surface or the locking and sealing surface as a sealing surface for abutting the outer peripheral surface of the valve element to stop and set it to a shut-off position, and set the operating torque such that the selected sealing surface becomes the shut-off position.

5. A valve comprising the inner peripheral sealing structure according to claim 2, wherein, The valve is provided with a rotary drive member for rotating the valve element, The rotary drive member is configured to select any one of the first sealing surface, the second sealing surface, and the locking and sealing surface as a sealing surface for abutting the outer peripheral surface of the valve element to stop and set it to a shut-off position, and set the operating torque such that the selected sealing surface becomes the shut-off position.

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