JP2020139583A - Valve body of double-eccentric type butterfly valve and double-eccentric type butterfly valve - Google Patents

Abstract

To provide a valve body of a double-eccentric type butterfly valve which can secure seal performance by suppressing the generation of the deformation and deflection of a valve body at valve-closing with respect to even a high-pressure fluid while achieving weight reduction, can prevent the generation of a stress concentration caused by a load applied from the fluid, and is improved in operability, reliability and durability, and the butterfly valve.SOLUTION: There is provided a valve body 1 of a double-eccentric type butterfly valve in which boss parts 3, 4 for accommodating stems 8, and rib parts 6,7 extending toward both outer edges of the valve body in directions intersecting with the stems 8 from the boss parts 3, 4 are arranged at a surface 2a of a disc 2 at one side, and the rib parts 6, 7 and the boss parts 3, 4 are continuously connected to each other so that a step is not formed in a height direction viewed from the surface 2a of the disc 2, and a linear boundary portion is not generated at side wall faces of the boss parts 3, 4. There is also provided the butterfly valve 51.SELECTED DRAWING: Figure 1

Description

The present invention relates to a valve body of a double eccentric butterfly valve in which the center of a stem is doubly eccentric and attached, and more particularly to a valve body suitable for a flow path of a high-pressure fluid and a butterfly valve provided with the valve body.

In general, butterfly valves have a simple structure, are small and lightweight, have the structural advantage of being able to reduce the inter-plane dimensions compared to other valve types, and open and close the valve within a 90-degree operating range. Since it can be operated, it is suitable for automatic operation and also has the functional merit of excellent flow control, so it is widely used in various forms such as water supply and drainage, air conditioning equipment, factory processes, etc. Recently. Therefore, there is a demand for a fluid that can handle higher pressure fluids than before.

Conventionally, a double eccentric butterfly valve has been known as a valve suitable for a high-pressure fluid flow path. The double eccentric butterfly valve is installed so that the position of the stem is doubly eccentric with respect to the valve body, and this double eccentricity ensures good sealing performance even at high pressure and at the same time prevents wear on the seat surface. Can be prevented.

When using a butterfly valve under high pressure, a large fluid resistance acts on the valve body with valve opening and intermediate opening, and in particular, when fully closed, the total fluid pressure in the pipeline is applied to the valve body surface, and the valve body is affected. The load from the working fluid is maximized. When a load is received from the fluid, the valve body is deformed and the tip portion of the valve body is greatly bent, and when this tip portion moves from the seating position of the seat ring, the sealing property is impaired. Therefore, it is necessary to secure the strength that the valve body does not easily bend. However, if the wall thickness of the valve body is increased to secure the strength, the weight of the valve body increases, the cost increases, and the operability of the valve is impaired. Occurs. In order to avoid this, it is required to reduce the weight of the valve body, secure its strength, reduce the deflection and stress concentration, and reduce the fluid resistance of the valve opening and the intermediate opening.

As the valve body of the butterfly valve having improved strength, for example, the valve body of the butterfly valve of Patent Document 1 is disclosed. The valve body of this butterfly valve is for a central butterfly valve, and a plurality of lateral ribs extending in the X direction starting from the Y axis are formed, thereby increasing the rigidity while reducing the wall thickness and also reducing the weight. It is something to try.

Further, in the valve body of the central butterfly valve of Patent Document 2, a valve body in which a plurality of circular ribs intersecting with a boss portion are concentrically raised on the front and back surfaces of a substrate is disclosed. In this valve body, the circular ribs provide a substantially uniform cross-sectional coefficient in a cross section at any angle with respect to the center line of the valve body, and the rigidity of the valve body is made substantially uniform throughout the valve body to obtain a highly rigid valve body. It is something to get.

Japanese Patent No. 3676785 Japanese Patent No. 4569927

However, the valve body of the butterfly valve of Patent Document 1 is reinforced by providing ribs on the valve body to increase the rigidity of the valve body, but when the valve body is reinforced by providing ribs, a stress concentration portion is formed. If this happens, cracks and breaks are likely to occur at that portion, and the durability of the valve body may not be sufficiently obtained.

Further, in the valve body of the butterfly valve of Patent Document 2, the rigidity of the valve body is increased by making the rigidity of the entire valve body substantially uniform, but the valve body is increased by the load acting on the valve body from the fluid. The magnitude of the bending moment that causes bending varies greatly depending on the part of the valve body. That is, while the central part of the valve body in the vertical direction is supported by the stem, there are no support parts at the left and right ends of the valve body, so that the maximum bending moment acts especially on the center line in the lateral direction of the valve body. However, the amount of deflection of this part is the largest. If the valve body of the butterfly valve of Patent Document 2 is to be given rigidity that does not impair the sealing performance when the valve is closed even if both the left and right ends are bent, the rigidity of the entire valve body is adjusted to the rigidity of the portion having the largest bending moment. This is necessary, and the wall thickness of the entire valve body increases, the manufacturing cost increases, and the weight increase of the valve body causes deterioration of valve operability.

The present invention has been developed in order to solve the above-mentioned problems, and an object of the present invention is to generate deformation and bending of the valve body when the valve is closed even with a high-pressure fluid while reducing the weight. With the valve body of a double eccentric butterfly valve that can prevent stress concentration due to the load acting from the fluid and improve operability, reliability and durability. To provide a butterfly valve.

In order to achieve the above object, the invention according to claim 1 is a valve body of a double eccentric butterfly valve having a circular outer shape, and a boss portion for accommodating a stem is provided on one surface of the disc. And a rib part extending from the boss part toward both outer edges of the valve body in the direction intersecting the stem, and the boss part is divided into a plurality of parts so that the stem is partially exposed. The rib portion is provided on each of the divided boss portions so that the rib portion and the boss portion do not have a step in the height direction when viewed from the surface of the disc, and the side wall surface of the boss portion is straight. It is a valve body of a double eccentric butterfly valve characterized in that it is continuously connected so as not to generate a specific boundary portion.

In the invention according to claim 2, the boss portion is divided into two so that the stem is exposed near the center of the valve body, and the rib portion is formed so as to be closer to the center side of the valve body in the boss portion. In addition, the valve of the double eccentric butterfly valve provided so that the side wall surface on the center side of the valve body of the boss portion and the side wall surface on the center side of the valve body of the rib portion form a continuous single flat surface. The body.

According to the third aspect of the present invention, the stems are mounted on the upper and lower shaft mounting portions of the short tubular body, the valve body is provided in the body, and the valve body is openably and closably provided via the stem. It is an eccentric butterfly valve.

According to the invention of claim 1, since the rib portions extending from the boss portion toward both outer edges of the valve body in the direction intersecting the stem are provided, the load acting in the direction intersecting the stem of the valve body is applied. It can be received by this rib part and directly transmitted to the boss part to support it, and by improving the rigidity in the direction intersecting the stem of the valve body, the amount of bending at both left and right ends of the disc due to the bending moment acting by the load of the fluid. Since it is possible to secure the sealing property by suppressing the thickness of the disc, the wall thickness of the entire disc can be suppressed and the weight of the disc can be reduced.

Further, a smooth R surface is formed so that the rib portion and the boss portion do not have a step in the height direction when viewed from the surface of the disc, and the side wall surface of the boss portion does not have a linear boundary portion. Because they are continuously connected, when a fluid load acts on the valve body, stress concentration occurs at the connecting part of the boss part and rib part that support the load, such as a step and a linear boundary part. As a result of the absence and the stress being appropriately dispersed, cracks and breaks caused by stress concentration are unlikely to occur, so that the durability of the valve body can be improved.

According to the invention of claim 2, the boss portion is divided into two so that the stem is exposed near the center of the valve body, and the rib portion is formed closer to the center side of the valve body in the boss portion. Since the maximum length is secured near the center of the valve body where the bending moment acts most due to the load, and the rib part is provided, the lateral bending rigidity of the center part of the valve body is increased, and the left and right ends of the disc are bent. The amount can be suppressed and the sealing property can be ensured.

Further, since the side wall surface on the valve body center side of the boss portion and the side wall surface on the valve body center side of the rib portion are provided so as to form a continuous single flat surface, a step or a linear boundary portion is provided. There is no such part where stress concentration occurs, the stress at the connection part between the boss part and the rib part can be dispersed more effectively, and cracks and breaks caused by stress concentration are less likely to occur. A valve body having excellent durability can be obtained.

According to the invention of claim 3, the valve body is lightweight, has high rigidity, is excellent in sealing property, and is provided with a valve body in which cracks and breaks due to stress concentration are unlikely to occur, so that operability and reliability are achieved. A butterfly valve suitable for a high-pressure fluid having excellent properties and durability can be obtained.

It is a perspective view which shows the preferable embodiment of the valve body of the double eccentric butterfly valve in this invention. It is a front view of FIG. It is a top view of FIG. It is sectional drawing of the part AA of FIG. It is a front view of the valve body of the double eccentric butterfly valve of the comparative example. It is a perspective view which shows the embodiment of the double eccentric butterfly valve.

Hereinafter, a valve body of the double eccentric butterfly valve in the present invention and a preferred embodiment of the butterfly valve provided with the valve body will be described in detail with reference to the drawings. 1, FIG. 2, FIG. 3, and FIG. 4 show a perspective view, a front view, a plan view, and a cross-sectional view of the valve body of the double eccentric butterfly valve according to the present invention.

As shown in FIGS. 1 and 2, the valve body 1 of the double eccentric butterfly valve has a disc-shaped disc 2, and boss portions 3 and 4 are formed on the upper and lower surfaces 2a on one side of the disc 2. , An annular rib portion 5 and rib portions 6 and 7 are provided on the surface 2a.

The boss portion is divided into two parts, an upper boss portion 3 and a lower boss portion 4 of the disc 2, and is provided with the stem 8 exposed. The boss portion 3 and the boss portion 4 are provided with the stem 8 Holes 10 and 11 for mounting the stem 8 are formed so that the stem 8 can be inserted.

As shown in FIG. 3, the boss portion 3 separates the center S of the hole portion 10 from the seal position 2b of the disc (single eccentricity) and also from the center line of the valve body 1 (valve center axis 12). It is provided on the surface 2a of the disc 2 in a state of being separated by a distance D (double eccentricity). Further, as shown in FIG. 2, the boss portion 4 is provided line-symmetrically with the boss portion 3 with the valve body horizontal axis 14 as the axis of symmetry, and the hole portion 10 and the hole portion 11 are formed coaxially. ..

When the stem 8 was inserted into the hole 10 of the boss 3 and the hole 11 of the boss 4, the center S of the hole 10 and the hole 11 became the rotation center of the stem 8, and the valve body 1 rotated the stem 8. Occasionally, the valve can be closed by eccentrically rotating around the center S of the hole 10 and the hole 11. The valve body 1 is made of metal, and for example, stainless steel such as SCS13A or SCS14A is used.

The annular rib portion 5 has a ring shape concentric with the disc 2, that is, a ring shape having a diameter shorter than the diameter of the disc 2 centering on the intersection O of the valve body central axis 12 and the valve body horizontal axis 14 of the disc 2, and the surface of the disc. A protrusion is formed on 2a. The annular rib portion 5 is connected to the side wall surfaces 3a and 3b of the boss portion 3 and the side wall surfaces 4a and 4b of the boss portion 4 as shown in FIG. 2, and the cross-sectional shape is trapezoidal as shown in FIG. .. In this way, the ring-shaped annular rib portion 5 is projected and formed on the surface 2a of the disc 2, thereby increasing the strength and bending rigidity of the entire disc 2.

As shown in FIG. 2, the rib portion 6 is provided in a substantially horizontal state near the side wall surface 3a on the valve body center side (valve body horizontal axis 14 side) of the boss portion 3, and the side wall surface 3b of the boss portion 3 is provided. It is composed of a long rib 15 connected to the boss portion 3 and a short rib 16 connected to the side wall surface 3c of the boss portion 3. Further, the tips of the long rib 15 and the short rib 16 on the outer edge side of the valve body are connected to and integrated with the annular rib portion 5.

Similarly, the rib portion 7 is provided in a substantially horizontal state near the side wall surface 4a on the valve body center side (valve body horizontal axis 14 side) of the boss portion 4, and is connected to the side wall surface 4b of the boss portion 4. It is composed of a long rib 17 and a short rib 18 connected to the side wall surface 4c of the boss portion 4. Further, the tips of the long rib 17 and the short rib 18 on the outer edge side of the valve body are connected to and integrated with the annular rib portion 5.

In FIG. 2, in order to clarify the positional relationship between the rib portions 6 and 7 and the annular rib portion 5, the tips of the long ribs 15 and the short ribs 16 and the long ribs 17 and the short ribs 18 on the outer edge side of the valve body are clarified. The boundary between the and the annular rib portion 5 is represented by a line, but in reality, these boundaries are also continuously connected by forming a smooth R surface so as not to generate a step or a linear boundary portion, and stress. It is configured so that concentration does not occur. (The same applies to FIGS. 1, 3 and 4).

As shown in FIG. 2, the boss portion 3 and the boss portion 4, and the rib portion 6 and the rib portion 7 are similarly configured except that they are line-symmetrical with the valve body horizontal axis 14 as the axis of symmetry. Therefore, the details of the rib portions 6 and 7 will be described below with reference to the rib portions 6.

As shown in FIG. 2, in the rib portion 6, a long rib 15 and a short rib 16 are formed from the side wall surfaces 3b and 3c of the boss portion 3 toward both outer edges of the valve body 1 up to the annular rib portion 5. However, the annular rib portion 5 is formed concentrically with the disc 2 about the center point O of the disc 2, whereas the stem central shaft 20 which is the center of the boss portion 3 is from the valve body central shaft 12. Since the distance D is deviated, the length of the long rib 15 is 2D longer than the length of the short rib 16 even if the side wall surfaces 3b and 3c of the same boss portion 3 are the starting points.

Further, as shown in FIG. 3, the shapes of the long rib 15 and the short rib 16 seen from the end surface 3d side of the valve body outer peripheral side of the boss portion 3 are substantially right triangles, and correspond to the hypotenuses of the substantially right triangles. The inclined upper surface 15c of the long rib 1 and the inclined upper surface 16c of the short lube 16 gradually increase the height from the surface 2a of the disc 2 from the side wall surfaces 3b and 3c of the boss portion 3 toward both outer edges of the valve body 1. It is provided to reduce.

The side wall surface 3a on the valve body center side of the boss portion 3, the side wall surface 15a on the valve body center side of the long rib 15, and the side wall surface 16a on the valve body center side of the short rib 16 form a single plane. That is, they are connected so as to be so-called flush. Therefore, the length of the rib portion 6 can be secured to the maximum, and the stress of the connecting portion between the boss portion 3 and the rib portion 6 can be more effectively dispersed.

As shown in FIGS. 2 and 3, the side wall surface 15b on the opposite side of the side wall surface 15a of the long rib 15 has a smooth R surface so as not to form a linear boundary portion with the side wall surface 3b of the boss portion 3. The inclined upper surface 15c of the long rib 15 is formed and continuously connected, and the inclined upper surface 15c of the long rib 15 has a smooth radius with respect to the side wall surface 3c of the boss portion 3 so as not to cause a step in the height direction from the surface 2a of the disc 2. They form a surface and are continuously connected.

Similarly, the side wall surface 16b on the opposite side of the side wall surface 16a of the short rib 16 is continuously connected by forming a smooth R surface so as not to form a linear boundary portion with the side wall surface 4b of the boss portion 4. The inclined upper surface 16c of the end length rib 16 forms a smooth R surface with respect to the side wall surface 4c of the boss portion 4 so as not to cause a step in the height direction seen from the surface 2a of the disc 2. It is connected.

In this way, the long rib 15 and the short rib 16 of the rib portion 6 form a smooth R surface so as not to generate a step or a linear boundary portion, and are continuously connected to the boss portion 3, and the boss portion 3 is connected. Since it is configured integrally with the boss portion 3 and the rib portion 6 that support the load of the fluid, there is no part where stress concentration occurs such as a step or a linear boundary portion, so that stress concentration occurs. As a result of the stress being appropriately dispersed in the boss portion 3 and the rib portion 6, cracks and breakages caused by stress concentration are less likely to occur, and the durability of the valve body 1 is improved. Can be done.

Further, the long rib 15 and the short rib 16 are directly connected to the boss portion 3 having extremely high rigidity, and the long rib 15, the short rib 16, and the boss portion 3 are integrated to form the rib portion 6. Therefore, the bending rigidity of the entire rib portion 6 can be greatly improved.

Generally, in a butterfly valve, when a fluid load acts on the valve body when the valve is closed, the central part of the valve body in the vertical direction is supported by the stem, while the support parts are provided at both left and right ends in the horizontal direction of the valve body. Since it does not exist, the maximum bending moment acts in the lateral direction of the central portion of the valve body, and the amount of deflection at both the left and right ends of the central portion of the valve body is the largest.

However, in the valve body 1, the rib portion 6 and the rib portion 7 have the maximum length secured by sandwiching the valve body horizontal shaft 14 near the center of the valve body where the maximum bending moment acts due to the pressure of the fluid when the valve is closed. Since the lateral bending rigidity of the central portion of the disc 2 is increased by providing the discs in parallel with each other, the amount of bending of the left and right ends of the disc 2 due to the bending moment acting by the load of the fluid when the valve is closed is suppressed and the sealing performance is improved. It becomes possible to secure the above, and it is possible to suppress an increase in the weight of the disc 2 without requiring much reinforcement in other parts of the disc 2.

As described above, in the valve body 1, the annular rib portion 5 is provided to increase the strength and rigidity of the entire disc 2, and the valve is located near the center of the valve body where the maximum bending moment acts due to the pressure of the fluid when the valve is closed. By providing the rib portion 6 and the rib portion 7 having the maximum length with the horizontal axis 14 in parallel in parallel, the lateral bending rigidity of the central portion of the disc 2 is increased, and the disc 2 is used when the valve is closed. The amount of deflection at both the left and right ends is suppressed.

Further, the annular rib portion 5 and the boss portions 3 and 4, the rib portion 6 and the boss portion 3, the rib portion 7 and the boss portion 4, and the annular rib portion 5 and the rib portions 6 and 7 are connected. Since the boss portions 3 and 4, the annular rib portion 5 and the rib portions 6 and 7 are integrally formed, the load and the bending moment acting on the valve body 1 can be collectively borne by these. .. As a result, it is more effective than the case where the annular rib portion 5 and the rib portions 6 and 7 are not connected to the boss portions 3 and 4 and the annular rib portion 5 and the rib portions 6 and 7 are not connected. It is possible to suppress the occurrence of deformation and bending of the valve body 1 and secure the sealing property.

Subsequently, as shown in FIG. 3, the side surface shapes of the long rib 15 and the short rib 16 of the rib portion 6 as seen from the end surface 3d side of the boss portion 3 are substantially right triangles. As described above, the reason why the long rib 15 and the short rib 16 are formed into a substantially right triangle and the side surface shape of the long rib 15 is set to be larger than the side shape of the short rib 16 will be described below.

In the butterfly valve, the outer edge of the disc-shaped disc is in close contact with the valve seat of the body to seal it, but when the amount of deflection of the outer edge of the disc becomes large, the surface pressure in close contact with the valve seat of the body is insufficient. Therefore, it is necessary to keep the amount of bending of the outer edge of the disc when the valve is closed within a range in which sufficient sealing property can be obtained.

Further, in the case of the double eccentric butterfly valve, the stem central axis and the valve body central axis do not match and have an eccentric positional relationship, so that the distances from the stem central axis to the left and right ends of the disc are different. Therefore, when a load is received from the fluid, the side having a long distance from the stem central axis (hereinafter referred to as the long side) is larger than the side having a short distance from the stem central axis (hereinafter referred to as the short side). A bending moment is generated, and the amount of bending of the outer edge portion on the long side becomes larger than the amount of bending of the outer edge portion on the short side. In a double eccentric butterfly valve, if the amount of deflection at both the left and right ends of the disc is different when the valve is closed, the surface pressure in close contact with the valve seat on one side becomes insufficient, which causes a decrease in sealing performance.

Therefore, in the double eccentric butterfly valve, the amount of deflection at the left and right ends of the disc when the valve is closed is suppressed, and the difference in the amount of deflection at the left and right ends of the disc caused by the eccentricity of the stem is minimized, preferably left and right. It is required that there is no difference in the amount of bending at the edges.

In the valve body of the double eccentric butterfly valve of the present invention, by making a difference in the degree of reinforcement of the disc 2 by the rib portions 6 and 7, that is, the rigidity of the long side that flexes greatly and the rigidity of the short side that flexes little By making it higher than the above, the amount of bending at the left and right ends of the disc 2 is equalized.

The rib portions 6 and 7 provided on the surface 2a of the disc 2 have a larger cross-sectional coefficient as the height from the surface 2a increases, and have the effect of making the disc 2 less likely to bend. Therefore, by providing the height of the long rib 15 provided on the long side higher than the height of the short rib 16 provided on the short side as a whole, the long side provided with the long rib 15 can be made difficult to bend.

That is, as shown in FIG. 4, when compared at positions equidistant L from the stem central axis 20, the height from the surface 2a of the disc 2 of the long rib 15 provided on the long side except for the boss portion 3 The heights of the long ribs 15 and the short ribs 16 are set so that the height Hl is higher than the height Hs from the surface 2a of the disc 2 of the short ribs 16 provided on the short side.

By setting the heights of the long ribs 15 and the short ribs 16 in this way, the long side, which is more flexible, is reinforced and less likely to bend than the short side, and as a result, the outer edge of the long side and the outer edge portion The difference in the amount of deflection of the outer edge on the short side can be reduced.

The height relationship between the long rib 15 provided on the long side and the short rib 16 provided on the short side from the surface 2a does not necessarily have to be established at all positions of the ribs, and it is necessary for design reasons. The height relationship may be partially reversed. For example, the long rib 15 may be higher than the short rib 16 in comparison with the average height.

From the viewpoint of manufacturability, ribs for reinforcing such a valve body are often provided so that the height gradually decreases from the boss portion toward the outer edge side of the disc, and the upper surface of the rib is connected to the boss portion. Tilt at a substantially constant angle except near the connection and near the connection on the outer edge of the valve body. In this case, the shape of the rib is the side (bottom side) at the position corresponding to the surface of the disc when viewed from the side, the side (hypotenuse) of the inclined portion at a certain angle on the upper surface of the rib, and the side (height) on the stem central axis. ) Can be approximated to a right triangle.

For the strength of ribs having such a virtual right triangle side shape, the idea of a beam of equal strength in strength of materials (a cantilever beam that receives an evenly distributed load on the base of a right triangle) may be applicable. .. Since the amount of deflection of the cantilever beam that is close to the rib can be calculated from the formula of the beam of equal strength, the difference in the amount of deflection of the rib tip on the long side and the short side should be small based on this formula. The heights of the virtual right triangles on the long side and the short side (heights Ha and Hb of the virtual right triangles on the stem central axis 20) can be set.

When the side surface shape of the rib portion is obtained by this method, the height of the rib provided to increase the lateral bending rigidity of the disc can be minimized, and the weight increase of the valve body can be suppressed.

However, in reality, the load of the fluid when the valve is closed is applied not only to the rib part but also to the entire valve body including the disc and boss part, and the amount of deflection is affected by the thickness and size of the disc. In many cases, the idea of a beam of equal strength cannot be applied as it is, but the difference in height between the long side and the short side of the virtual right triangle is at least the height derived based on the idea of a beam of equal strength. It is preferable to set it at least the difference between.

As shown in FIG. 4, the long ribs 15 and the short ribs 16 are substantially constant so that their inclined upper surfaces 15c and 16c gradually rise from the outer edge side ends of the valve body toward the boss portions 3 and 4. The rib center line 24 passing through the intersection P of the virtual lines 22 and 23 which are provided so as to be inclined at an angle and whose inclined upper surfaces 15c and 16c are virtually extended toward the center of the valve body is a stem with respect to the valve body center axis 12. It is located on the opposite side of the central axis 20.

As described above, in the valve body 1, the rib triangle composed of the long rib 15, the short rib 16, and the surface 2a of the disc 2 (in FIG. 4, the virtual line 22 extending the inclined upper surface 15C of the long rib 15 and the virtual line 22 The rib center line 24 passing through the apex P of the virtual line 23 extending the inclined upper surface 16C of the short rib 16 and the line 25 indicating the surface of the disc 2 is provided with respect to the valve body center axis 12 and the stem center axis 20. By offsetting to the opposite side of the disc, the section modulus on the side that is easy to bend is made larger than the section modulus on the side that is hard to bend to increase the rigidity, and the amount of bending at the left and right ends of the disc is equalized.

In order to confirm the effect of reducing the difference in the amount of deflection at the left and right ends of the disc in the valve body of the double eccentric butterfly valve of the present invention and the effect of suppressing the valve body weight, the example shown in FIG. 1 and the comparative example shown in FIG. The valve body of the double eccentric butterfly valve was analyzed by FEM (Finite Element Method: finite element method).

The embodiment of FIG. 1 has the configuration as described above, but the valve body 31 of the comparative example shown in FIG. 5 has a disk-shaped disc 32, and a boss portion is formed on the upper and lower portions of the surface 32a on one side of the disc 32. 33, 34 are provided, and the surface 32a is provided with an annular rib portion 35 for reinforcement, rib portions 36, 37, 38, 39 for reinforcement, and lightening portions 40a, 40b, 40c, 40d, 40e, 40f. It is composed.

In the valve body 31 of the double eccentric butterfly valve of the comparative example, the annular rib portion 35 and the rib portions 36, 37, 38, 39 are connected, but the boss portions 33, 34 provided at the upper and lower parts of the disc 2. Is not connected to the rib portions 36, 37, 38, 39. The major difference from the embodiment is that the boss portion and the rib portion are not connected. The valve body of the double eccentric butterfly valve of this comparative example has a track record of use in a rose fly valve having a maximum allowable pressure of 2 Mpa, and has excellent sealing performance.

In the analysis, for each of the valve body sizes shown in Table 1, the displacement amount (deflection amount) and the valve body at the left and right ends on the horizontal axis of the valve body when a fluid pressure of 5.11 MPa is applied to Examples and Comparative Examples. I asked for the weight. Based on this result, the reduction rate (deflection improvement rate) in which the difference in the amount of deflection at the left and right ends of the valve body decreased in the examples with respect to the comparative example was calculated.
Table 1 shows the deflection improvement rate and the valve body weight increase rate for each size obtained by the analysis. In Table 1, the forward direction means the case where the fluid pressure is applied from the primary side, and the reverse direction means the case where the fluid pressure is applied from the secondary side.

As shown in Table 1, according to the configuration of the valve body of the example, the bending improving effect of reducing the difference in the amount of bending at the left and right ends of the valve body is remarkable without significantly increasing the weight of the valve body as compared with the comparative example. It was confirmed that it can be obtained in.

Next, an example in which the valve body 1 according to the present invention is attached to the secondary eccentric butterfly valve will be described. FIG. 6 shows a perspective view of a secondary eccentric butterfly valve 51 in which the valve body 1 according to the present invention is mounted on the valve body 52 and the valve is fully closed.

The valve body 52 has a short cylinder-shaped body 53, and a shaft mounting portion 54 for shaft mounting the stem 8 of the valve body 1 is provided on the upper and lower portions of the body 53. The valve body 1 is arranged in the body 53, and in this state, the stem 8 is axially mounted in the hole 10 of the boss portion 3 of the valve body 1, and the valve body 1 is integrally fixed to the stem 8 with a taper pin (not shown). As a result, the stem 8 can rotate with respect to the body 53 and cannot move in the vertical direction, the valve body 1 is arranged in a predetermined position in the body 53, and the stem 8 rotates. The valve body 1 can be freely opened and closed via the stem 8.

The double eccentric butterfly valve 51 is either when the fluid pressure is applied from the surface side of the valve body 1 where the boss portion 3 is provided, or when the fluid pressure is applied from the opposite side of the surface where the boss portion 3 is provided. It is also possible to reliably seal in the valve closed state in both flow directions.

Further, a handle for manual operation can be attached to the upper end of the stem 8 to manually open and close the valve, or an actuator can be mounted to automatically open and close the valve.

As described above, the valve body of the double eccentric rose fly valve of the present invention has a lateral rib that secures the maximum length near the center of the disc where a large bending moment acts due to the pressure of the fluid when the valve is closed. Since the flexural rigidity of the disc is increased by connecting it to the part, the bending of the left and right ends of the disc that occurs when the valve is closed is suppressed without significantly increasing the weight compared to the conventional valve body. be able to.

Further, since the boss portion and the rib portion are continuously connected by forming a smooth R surface so that there is no portion where stress concentration occurs such as a step or a linear boundary portion, the boss portion and the rib portion are connected. Since the stress of the connecting portion with the portion can be dispersed more effectively, cracks and breaks caused by stress concentration are less likely to occur, and the durability is excellent.

The double eccentric butterfly valve of the present invention is lightweight, has high rigidity, and has excellent sealing performance, and is provided with a valve body that is less likely to cause cracks or breakage due to stress concentration. It has excellent reliability and durability, and can be applied to fluids with higher pressure than before.

1 Valve body 2 Disc 2a Surface 3, 4 Boss part 5 Circular rib part 6, 7 Rib part 8 Stem 51 Secondary eccentric butterfly valve 52 Valve body C Distance between the seal position of the disc and the center of the hole of the boss D Distance between the central axis of the valve body and the center of the hole in the boss Ha The height of the right triangle created by the virtual long rib on the stem central axis Hb The height of the right triangle created by the virtual short rib on the stem central axis Hl Height from the surface of the long rib disc at a distance L from the stem center axis Hs Height from the surface of the short rib disc at a distance L from the stem center axis O Valve center axis and valve body horizontal Axis intersection P Long rib, short rib and rib triangular apex composed of the surface of the disc S Center of the hole in the boss

Claims (3)

A valve body of a double eccentric butterfly valve having a circular outer shape, and a boss portion for accommodating a stem and a valve body in a direction intersecting the stem from the boss portion on one surface of the disc. A rib portion extending toward both outer edge portions of the above is provided, and the boss portion is divided into a plurality of parts so that the stem is partially exposed, and the rib portion is divided into each boss portion. It is provided so that the rib portion and the boss portion do not have a step in the height direction seen from the surface of the disc, and the side wall surface of the boss portion does not have a linear boundary portion. A valve body of a double eccentric butterfly valve characterized by being continuously connected. The boss portion is divided into two so that the stem is exposed near the center of the valve body, and the rib portion is formed so as to be closer to the center side of the valve body in the boss portion. The double eccentric shape according to claim 1, wherein the side wall surface on the valve body center side of the boss portion and the side wall surface on the valve body center side of the rib portion are provided so as to form a continuous single flat surface. The valve body of the butterfly valve. The stem is mounted on the upper and lower shaft mounting portions of the short tubular body, and the valve body according to claim 1 or 2 is provided in the body, and the valve body is provided so as to be openable and closable via the stem. Double eccentric butterfly valve.

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