JP2004044672A - Seat structure for metal seat butterfly valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat structure for a butterfly valve enabling a groove to be easily processed thereon and capable of reducing the difference in forces working on the inside and the outside of a valve casing seat when a valve body is in a fully closed position. <P>SOLUTION: When the valve body 6 is in a fully closed position S, a plane B including a valve body seat 11 tilts at a predetermined angle α in regard to a passage cross sectional surface A. A seal member 20 for sealing a space 19 between the valve casing seat 7 and a valve casing 2 and a pair of grooves 21, 22 are provided inside the valve casing 2. The grooves 21, 22 are parallely divided to an upstream side and a downstream side in regard to the passage cross sectional surface A. The seal member 20 is divided into a pair of semicircular seal pieces 20a, 20b. One of the seal pieces 20a is fitted into the upstream side groove 21 and positioned on one side of a passage axial center 3, and the other seal piece 20b is fitted into the downstream side groove 22 and positioned on the other side of the passage axial center 3. When the valve body 6 is in a fully closed position S, both the seal pieces 20a and 20b oppose the valve body seat 11 on a plane on which the valve body 6 is orthogonal to a shaft center 4 of a shaft rod 5 and includes the passage axial center as well. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a metal seat butterfly valve seat structure in which a valve body sheet is in close contact with a valve box sheet in a fully closed position, so that water stopping performance is ensured.
[0002]
[Prior art]
Conventionally, as a seat structure of this type of metal seat butterfly valve, for example, as shown in FIG. 11, a valve box sheet 52 made of a cylindrical metal material is provided in a valve box 51, In addition, a valve body 55 that rotates about an axis 54 of the valve rod 53 and opens and closes a valve box flow path is provided. As shown by the solid line in FIG. 11, when the valve element 55 is in the fully closed position S, the valve element 55 is orthogonal to the flow path axis 56 in the valve box 51 and includes a flow path section A including the axis 54. Is parallel to.
[0003]
Further, a valve body sheet 57 made of a metal material that is in contact with the inner peripheral surface of the valve box sheet 52 when the valve body 55 is at the fully closed position S is provided on the peripheral portion of the valve body 55. At the fully closed position S, the plane B including the valve body sheet 57 is inclined at a predetermined inclination angle α in the opening direction of the valve body 55 around the axis 54 with respect to the flow path section A. are doing.
[0004]
In the valve box 51, an O-ring 59 for sealing a gap 58 between the outer peripheral surface of the valve box sheet 52 and the inner peripheral surface of the valve box 51 on the upstream side and the downstream side of the valve box flow path. A groove 60 for fitting the ring 59 is formed. The O-ring 59 and the groove 60 are located on the flow path section A.
[0005]
Note that a ring-shaped stopper 61 that fixes the valve box sheet 52 in the direction of the flow path axis 56 is mounted in the valve box 51.
According to this, by rotating the valve body 55 to the fully closed position S, the outer peripheral surface of the valve body sheet 57 comes into close contact with the inner peripheral surface of the valve box sheet 52, and the water stopping performance is secured. At this time, the fluid flowing into the gap 58 between the outer peripheral surface of the valve case sheet 52 and the inner peripheral surface of the valve case 51 from the upstream side of the valve case flow path is sealed by the O-ring 59 and cannot pass through downstream. .
[0006]
Further, since the valve box sheet 52 is not integral with the valve box 51 but is separate from the valve box 51, even if a force acts on the valve box 51 due to a change in water pressure or ground, the valve box 51 is deformed, The ring 59 expands and contracts to absorb the deformation of the valve box 51, and the valve box sheet 52 slides in a watertight manner while maintaining the consistency with the valve body 55 without deformation. As a result, since the valve body sheet 57 is in close contact with the valve box sheet 52, no water leakage occurs, and the valve body 55 is not restrained by the deformation of the valve box sheet 52.
[0007]
Further, since the plane B including the valve element sheet 57 is inclined at a predetermined inclination angle α with respect to the flow path section A, when the valve element 55 rotates in the closing direction and reaches the fully closed position S, Since the valve body sheet 57 contacts the inner peripheral surface of the valve box sheet 52 for the first time, it is possible to prevent the valve body sheet 57 from sliding on the inner peripheral surface of the valve box sheet 52 and burning on the valve box sheet 52. it can.
[0008]
However, in the above-mentioned conventional type, the external pressure acting on the valve box seat 52 is Po and the internal pressure is Pi, the range from the upstream end of the valve box seat 52 to the O-ring 59 is J, and the valve body 55 is fully closed. When S, the range from the upstream end of the valve box sheet 52 to the valve body sheet 57 located on one side of the flow path axis 56 is defined as F, and the range from the upstream end of the valve box sheet 52 is Assuming that the range up to the valve seat 57 located on the other side of the flow path axis 56 is H, F <J on one side of the flow path axis 56, so that the external pressure Po is higher than the internal pressure Pi. There is a problem that extra force acts to cause a large difference in force between the inside and outside of the valve box sheet 52, and the valve box sheet 52 is pressed inward and deformed. In addition, since H> J on the other side of the flow path axis 56, the internal pressure Pi acts more than the external pressure Po, and a large difference in force is generated between the inside and outside of the valve box sheet 52. There is a problem that the box sheet 52 is deformed by being pressed outward.
[0009]
As a countermeasure against the above-mentioned problem, as shown in FIG. 12, the plane including the O-ring 59 is inclined at a predetermined inclination angle α with respect to the flow path It is possible to make it.
[0010]
According to this, the range from the upstream end of the valve box sheet 52 to the O-ring 59 located on one side of the flow path axis 56 is E, and the range from the upstream end of the valve box sheet 52 to the flow path axis Assuming that the range up to the O-ring 59 located on the other side of 56 is G, on one side of the flow channel axis 56, the range E and the range F are almost the same, so that the internal pressure Pi and the external pressure Po Acting almost equally, the difference between the forces inside and outside the valve box sheet 52 is eliminated, and the deformation of the valve box sheet 52 is prevented. In addition, since the range G and the range H substantially coincide with each other on the other side of the flow path axis 56, the internal pressure Pi and the external pressure Po act almost equally, and the difference between the internal and external forces of the valve box seat 52 is obtained. Is eliminated, and the deformation of the valve box sheet 52 is prevented.
[0011]
[Problems to be solved by the invention]
However, in the conventional type shown in FIG. 12, since the plane including the groove 60 also needs to be inclined at a predetermined inclination angle α with respect to the flow path cross section A, the groove 60 is formed inside the valve box 51 using a lathe or the like. When cutting the peripheral surface, the valve box 51 must be inclined, and the locus of the cutting process with respect to the groove 60 becomes elliptical. There is.
[0012]
The present invention provides a seat structure of a metal seat butterfly valve capable of easily processing a groove and further reducing a difference in force acting between inside and outside of a valve box seat when the valve body is rotated to a fully closed position. The purpose is to provide.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a valve box sheet made of a tubular metal material in a valve box, and the valve box sheet is rotated around the axis of a valve rod in the valve box sheet. A valve body sheet made of a metal material that is in contact with the inner peripheral surface of the valve box sheet when the valve body is in a fully closed position, provided on a peripheral edge of the valve body. In the closed position, the valve element is orthogonal to the flow path axis in the valve box and parallel to the flow path section including the valve stem axis, and when the valve element is in the fully closed position, the valve element The plane including the seat is inclined at a predetermined inclination angle in the opening direction of the valve body around the axis of the valve stem with respect to the cross section of the flow path, and the outer peripheral surface of the valve box sheet and the valve are disposed in the valve box. A seal member for sealing the gap between the inner peripheral surface of the box and the upstream and downstream sides of the valve box flow path, and a pair of grooves for mounting the seal member are provided. A sheet structure of the metal sheet butterfly valve,
The two grooves are formed on the inner peripheral surface of the valve box over the entire circumference, and are disposed so as to be distributed in parallel on the upstream side and the downstream side with respect to the flow path cross section. The first seal piece is fitted into the upstream groove and located on one side of the flow path axis, and the other seal piece is fitted into the downstream groove. When the valve is inserted and positioned on the other side of the flow channel axis and the valve body is in the fully closed position, one seal piece is orthogonal to the axis of the valve stem and on a plane including the flow channel axis. Is opposed to the valve body sheet located on one side of the flow path axis via the valve box sheet, and the other seal piece is attached to the valve body sheet located on the other side of the flow path axis. Are opposed to each other.
[0014]
According to this, both grooves are formed over the entire inner peripheral surface of the valve box, and are distributed in parallel on the upstream side and the downstream side with respect to the flow path cross section. The groove can be a constant radius centered on the axis. Therefore, the trajectory of the cutting process for the groove is not an elliptical shape but a perfect circle, and the groove can be easily cut using a normal lathe. In addition, since it is not necessary to incline the valve box when cutting the groove, the processing can be performed more easily.
[0015]
Also, when the valve body is in the fully closed position, on a plane orthogonal to the axis of the valve stem and including the flow path axis, one of the seal pieces faces the valve body sheet located on one side, The other sealing piece faces the valve body sheet located on the other side. Thereby, the range from the upstream end of the valve box sheet to one of the seal pieces on the plane is substantially the same as the range from the upstream end of the valve box sheet to the valve body sheet located on one side. In addition, the internal pressure and the external pressure act almost equally on the valve box sheet, and the difference between the forces acting on the inside and outside of the valve box sheet on one side of the flow path axis is reduced. Further, since the range from the upstream end of the valve box sheet to the other seal piece on the plane is substantially the same as the range from the upstream end of the valve box sheet to the valve body sheet located on the other side, The internal pressure and the external pressure act almost equally on the valve box sheet, and the difference between the forces acting inside and outside the valve box sheet on the other side of the flow path axis is reduced. Thereby, it is possible to prevent the valve box sheet from being deformed inward and outward.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 3, a metal sheet butterfly valve 1 includes a valve box 2 and a pair of rotatable shafts 4 that are rotatable about a flow axis 3 passing through the center of the valve box 2. It comprises a valve stem 5 and a valve element 6 provided on the valve stem 5.
[0017]
In the valve box 2, a valve box sheet 7 made of a cylindrical thin metal material is arranged concentrically with the flow path axis 3. Further, a pair of bosses 8 are formed in the valve box 2, and the two valve rods 5 are respectively inserted through the bosses 8 and a pair of through holes 9 formed in the valve box sheet 7. 8 rotatably held by a cylindrical bearing member 10 inserted.
[0018]
The valve element 6 is connected between the pair of valve rods 5 by a plurality of pins (not shown), and is provided in the valve box sheet 7 so as to be openable and closable. A valve body sheet 11 made of a metal material that comes into sliding contact with the inner peripheral surface of the valve box sheet 7 in a water-tight manner when the valve body 6 is at the fully closed position S is provided on the peripheral edge of the valve body 6.
[0019]
As shown in FIG. 4, in the fully closed position S, the valve element 6 is orthogonal to the flow path axis 3 and parallel to the flow path cross section A including the axis 4 of the valve rod 5. When the valve element 6 is in the fully closed position S, the plane B including the valve element sheet 11 has a predetermined inclination with respect to the flow path section A in the opening direction of the valve element 6 around the axis 4. Inclined at an angle α.
[0020]
As shown in FIGS. 1 and 2, a pair of ring-shaped shaft seal members 12 and 13 are disposed between the valve body 6 and the inner ends of the bearing members 10. Of these, the valve box-side shaft sealing material 12 disposed on the bearing member 10 side (outside) is made of, for example, a rubber product or an elastic material such as ethylene tetrafluoride resin, and as shown in FIG. The part is inserted into the through hole 9 of the valve box sheet 7 to seal between the valve rod 5 and the valve box sheet 7. Further, the valve body-side shaft seal 13 disposed on the valve body 6 side (that is, between the valve body 6 and the valve box-side shaft seal 12) is made of a metal material.
[0021]
Further, as shown in FIGS. 1 and 2, each of the boss portions 8 is provided with a fastening means 14 for pressing the valve-box-side shaft-sealing seal material 12 against the valve-body-side shaft-sealing seal material 13 via the bearing member 10. Is provided. These fastening means 14 include an annular pressing plate 15 arranged at the outer end of the bearing member 10, and a plurality of tightening means for attaching the pressing plate 15 to the boss portion 8 and tightening the pressing plate 15 to the valve body-side shaft sealing material 13. And an attached bolt 16.
[0022]
In the valve box 2, a ring-shaped stopper 17 for fixing the valve box sheet 7 in the direction of the flow axis 3 is disposed adjacent to the upstream end and the downstream end of the valve box sheet 7. It is attached to the valve box 2 by bolts 18.
[0023]
As shown in FIGS. 4 to 8, in the valve box 2, a gap 19 between the outer peripheral surface of the valve box sheet 7 and the inner peripheral surface of the valve box 2 is sealed on the upstream side and the downstream side of the valve box flow path. And a pair of grooves 21 and 22 for mounting the seal member 20.
[0024]
The two grooves 21 and 22 are formed on the entire inner peripheral surface of the valve box 2 and open on the inner peripheral side, and are distributed in parallel to the upstream and downstream sides with respect to the flow path cross section A. It is arranged. The seal member 20 is an elastic material (rubber or the like) having a circular cross section, and is divided at the valve stem 5 into a pair of semicircular seal pieces 20a and 20b.
[0025]
One of the seal pieces 20a is fitted into the upstream groove 21 and located on one side of the flow path axis 3. The other seal piece 20b is fitted in the groove 22 on the downstream side, and is located on the other side of the flow path axis 3 (opposite the one seal piece 20a). Each end of both seal pieces 20a and 20b is pressed against the outer peripheral surface of each valve box side shaft seal material 12, and each end of the seal pieces 20a and 20b and the valve box side shaft seal material. 12, the waterproofness between the outer peripheral surface and the outer peripheral surface is sufficiently ensured.
[0026]
When the valve element 6 is in the fully closed position S, as shown in FIG. 4, on the plane C (see FIGS. 1 and 2) orthogonal to the axis 4 and including the flow path axis 3, Seal piece 20a faces the valve body sheet 11 located on one side of the flow path axis 3 via the valve box sheet 7, and the other seal piece 20b is located on the other side of the flow path axis 3. The valve body sheet 11 faces through the valve box sheet 7. That is, on the plane C, the two seal pieces 20a and 20b are located on a straight line D passing through the shaft center 4 and the valve body sheet 11.
[0027]
Hereinafter, the operation of the above configuration will be described.
As shown in FIG. 8, both grooves 21 and 22 are respectively formed over the entire inner peripheral surface of the valve box 2, and are distributed in the upstream and downstream with respect to the flow path cross section A in parallel. Since it is provided, it can be a groove having a constant radius r centered on the flow path axis 3. Therefore, the trajectory of the cutting process for both the grooves 21 and 22 is not an elliptical shape but a perfect circle shape, and the grooves 21 and 22 can be easily cut using a normal lathe. In addition, when cutting the grooves 21 and 22, the valve box 2 does not need to be inclined, so that the processing can be performed more easily.
[0028]
As shown in FIG. 4, when the valve element 6 is in the fully closed position S, on the plane C orthogonal to the axis 4 of the valve stem 5 and including the flow path axis 3, one of the seal pieces 20 a The valve body sheet 11 is located on one side of the flow path axis 3 via the valve box sheet 7, and the other seal piece 20 b is located on the other side of the flow path axis 3. Oppose each other via the valve box sheet 7.
[0029]
Thereby, a range E from the upstream end of the valve box sheet 7 to the one seal piece 20a on the plane C and a range F from the upstream end of the valve box sheet 7 to the valve body sheet 11 located on one side from the upstream end. (E ≒ F), the internal pressure and the external pressure act on the valve box sheet 7 almost equally, and the force acting on the inside and outside of the valve box sheet 7 on one side of the flow path axis 3. The difference is reduced. Further, on the plane C, a range G from the upstream end of the valve box sheet 7 to the other seal piece 20b and a range H from the upstream end of the valve box sheet 7 to the valve body sheet 11 located on the other side. Are substantially the same (G ≒ H), the internal pressure and the external pressure act on the valve box sheet 7 almost equally, and the difference between the forces acting on the other side of the flow path axis 3 inside and outside the valve box sheet 7. Is reduced. Thus, the effect similar to that of the conventional type shown in FIG. 12 can be obtained, and the deformation of the valve box sheet 7 in and out can be prevented.
[0030]
Next, a second embodiment will be described with reference to FIG.
A backup member 30 is mounted in the pair of grooves 21 and 22. The backup member 30 is an elastic material (such as fluororesin) having a circular cross section, and a pair of semicircular portions is formed at the valve stem 5. It is divided into backup pieces 30a and 30b, and is provided on the side where both seal pieces 20a and 20b are not arranged.
[0031]
That is, one backup piece 30a is fitted in the groove 22 on the downstream side, and is located on one side of the flow path axis 3 (the same side as the one seal piece 20a). The other backup piece 30b is fitted into the upstream groove 21 and located on the other side of the flow path axis 3 (the same side as the other seal piece 20b). Each end of each of the backup pieces 30a and 30b is pressed against the outer peripheral surface of each of the valve box-side shaft seal materials 12.
[0032]
According to this, since the valve box sheet 7 is supported by the seal member 20 (that is, the seal pieces 20a and 20b) and the backup member 30 (that is, the backup pieces 30a and 30b), the valve box sheet 7 is stabilized, and the valve at the time of cavitation is generated. The vibration of the box sheet 7 can be suppressed.
[0033]
In the event that the seal member 20 is damaged, the amount of fluid leaking from the upstream side to the downstream side through the gap 19 between the valve box 2 and the valve box sheet 7 can be reduced by the backup member 30. it can.
[0034]
Next, a third embodiment will be described with reference to FIG.
The position of the upstream groove 21 and the one seal piece 20a is further moved to the upstream end side of the valve box sheet 7 than that of the first embodiment, and the downstream groove 22 and the other seal piece 20b are shifted. Are further shifted to the downstream end side of the valve box sheet 7 than in the first embodiment.
[0035]
According to this, when the valve element 6 is in the fully closed position S, the range E is smaller than the range F on a plane C orthogonal to the axis 4 of the valve stem 5 and including the flow path axis 3 ( E <F), the internal pressure acts on the valve box sheet 7 more than the external pressure. As a result, the valve box sheet 7 is slightly deformed outward on one side of the flow axis 3, and the contact surface pressure between the valve body sheet 11 and the valve box sheet 7 is reduced. However, at this time, at the fully closed position S, half of the valve element 6 within one side of the flow path axis 3 is pressed in the closing direction by water pressure (fluid pressure) acting from the upstream side. The contact surface pressure required for the seal (water stoppage) is secured.
[0036]
Further, since the range G becomes larger than the range H (G> H), the external pressure acts on the valve box sheet 7 more than the internal pressure. Thereby, the valve box sheet 7 is slightly deformed inward on the other side of the flow path axis 3, and the contact surface pressure between the valve body sheet 11 and the valve box sheet 7 is reduced to that of the first embodiment. Since it further rises, the occurrence of leakage can be more reliably prevented, and the water stopping performance is further improved.
[0037]
【The invention's effect】
As described above, according to the present invention, both grooves are formed on the inner peripheral surface of the valve box over the entire circumference, and are distributed and arranged in parallel on the upstream side and the downstream side with respect to the flow path cross section. Therefore, it is possible to form a groove having a constant radius around the axis of the flow path. Therefore, the trajectory of the cutting process for the groove is not an elliptical shape but a perfect circle, and the groove can be easily cut using a normal lathe. In addition, since it is not necessary to incline the valve box when cutting the groove, the processing can be performed more easily.
[0038]
Further, when the valve body is in the fully closed position, the internal pressure and the external pressure act almost equally on the valve box sheet on a plane orthogonal to the axis of the valve stem and including the flow axis, and The difference between the forces acting inside and outside is reduced. Thereby, it is possible to prevent the valve box sheet from being deformed inward and outward.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a butterfly valve according to a first embodiment of the present invention as viewed from the front.
FIG. 2 is a cross-sectional view of the butterfly valve as viewed from a side.
FIG. 3 is a view of the valve body of the butterfly valve as viewed from an axial direction of a valve stem.
4 is a cross-sectional view taken along a plane perpendicular to the axis of the valve stem of the butterfly valve and including the flow path axis, and corresponds to a view taken along the line XX in FIG. 2;
FIG. 5 is a sectional view showing a positional relationship between a seal piece and a valve body sheet in FIG. 4;
FIG. 6 is a view of a valve box sheet, a valve box-side shaft seal material, and a seal piece of the butterfly valve.
FIG. 7 is a view of the valve box sheet and the seal piece of the butterfly valve as viewed from the axial direction of the valve stem.
FIG. 8 is a cross-sectional view of the butterfly valve as viewed from the axial direction of the valve stem.
FIG. 9 is a cross-sectional view taken along a plane orthogonal to the axis of the valve stem of the butterfly valve and including the flow axis in the second embodiment of the present invention.
FIG. 10 is a cross-sectional view taken along a plane orthogonal to the axis of a valve stem of a butterfly valve and including the axis of a flow channel according to a third embodiment of the present invention.
FIG. 11 is a cross-sectional view taken along a plane orthogonal to the axis of a valve stem of a conventional butterfly valve and including the flow path axis.
FIG. 12 is a cross-sectional view taken along a plane perpendicular to the axis of a valve stem of a conventional butterfly valve and including the flow axis.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Butterfly valve 2 Valve box 3 Flow path axis 4 Valve stem axis 5 Valve stem 6 Valve element 7 Valve box sheet 11 Valve element sheet 19 Gap 20 Seal members 20a, 20b Seal piece 21 Upstream groove 22 Downstream side Groove A Flow path cross section B Plane C including valve body sheet C Plane S orthogonal to axis of valve stem and including flow path axis Fully closed position α Predetermined inclination angle

Claims (1)

A valve box sheet made of a cylindrical metal material is provided in the valve box, and a valve body that rotates about the axis of the valve rod and opens and closes the valve box flow path is provided in the valve box sheet. A valve body sheet made of a metal material that is in contact with the inner peripheral surface of the valve box sheet when the valve body is in the fully closed position is provided on the peripheral edge of the body. Is perpendicular to the flow path axis and parallel to the flow path cross section including the axis of the valve stem, and when the valve body is in the fully closed position, the plane including the valve element sheet is positioned with respect to the flow path cross section. The valve body is inclined at a predetermined inclination angle in the opening direction of the valve body around the axis of the valve stem, and a gap between the outer peripheral surface of the valve box sheet and the inner peripheral surface of the valve box is formed in the valve box. Metal seat butterfly valve seat provided with a seal member for sealing the upstream side and the downstream side of the flow path, and a pair of grooves for mounting the seal member A concrete,
The two grooves are formed on the inner peripheral surface of the valve box over the entire circumference, and are disposed so as to be distributed in parallel on the upstream side and the downstream side with respect to the flow path cross section. The first seal piece is fitted into the upstream groove and located on one side of the flow path axis, and the other seal piece is fitted into the downstream groove. When the valve is inserted and positioned on the other side of the flow channel axis and the valve body is in the fully closed position, one seal piece is orthogonal to the axis of the valve stem and on a plane including the flow channel axis. Is opposed to the valve body sheet located on one side of the flow path axis via the valve box sheet, and the other seal piece is attached to the valve body sheet located on the other side of the flow path axis. A seat structure of a metal seat butterfly valve, characterized in that the valve seat faces each other.

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