JP2008014378A - Sealing structure of valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure of a valve, which prevents a sheet member from slipping out while preventing deformation of the sheet member in accordance with increase of pressure of a sheet presser, and also prevents increase of opening and closing torque. <P>SOLUTION: An annular sheet member 9 made of rubber is provided in a sheet holding part formed in a valve element 4 and sandwiched and fixed from both sides by the sheet presser 10 and the sheet holding part. The sheet member 9 has a three-layer structure wherein a flexible layer 23 is sandwiched between a pair of rigid layers 24a, 24b so as to be integrally bonded. The rubber hardness of both the rigid layers 24a, 24b is higher than that of the flexible layer 23, and the flexible layer 23 slides and contacts with a valve seat part 7 on a valve box side provided in the valve box 2 when the valve element 4 rotates to a closing position S. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a seal structure of a valve such as a butterfly valve.

  Conventionally, in the eccentric butterfly valve 61 as shown in FIG. 12, a valve body 64 that opens and closes the flow path 63 is provided inside the valve box 62 so as to be rotatable around the axis of the valve rod 65. The valve box 62 has an annular valve box side valve seat 66 on the inner peripheral surface.

The seal structure for sealing between the valve body 64 and the valve box side valve seat 66 is configured as follows.
As shown in FIGS. 13 to 15, a seat holding portion 67 is formed on the outer peripheral edge of the valve body 64 over the entire circumference, and an annular seat member 68 made of rubber is formed on the seat holding portion 67. Is provided. Usually, the hardness of the rubber of the sheet member 68 is about Hs 60 to 70.

  Further, the sheet member 68 is sandwiched and fixed from both sides by an annular sheet retainer 69 and a retainer surface 67 a of the sheet holding portion 67. The sheet presser 69 is attached to the valve body 64 by a plurality of bolts 70. In the state in which the seat member 68 is attached, the outer peripheral edge of the seat member 68 protrudes by a predetermined amount A outwardly in the radial direction from the outer peripheral edges of the valve body 64 and the seat presser 69, as shown by the solid line in FIG. ing. Further, a groove portion 71 having a corrugated cross section is formed in each of the pressing surface 67a of the sheet holding portion 67 and the pressing surface 69a of the sheet pressing member 69 opposed thereto.

  According to this, as shown in FIG. 15, when the valve body 64 rotates to the closed position S, the flow path 63 in the valve box 62 is closed by the valve body 64, and the flow of fluid (for example, water) is blocked. The At this time, the outer peripheral edge of the seat member 68 is in sliding contact with the valve box side valve seat portion 66, and the space between the valve body 64 and the valve box 62 is sealed. Further, when the valve body 64 is rotated and opened in the opening direction from the closed position S, the fluid flows from the inlet 72 to the outlet 73 of the valve box 62.

  In Patent Document 1 below, seals in which groove portions 71 having a corrugated cross section are formed on the pressing surface 67a of the sheet holding portion 67 of the valve body 64, the pressing surface 69a of the sheet pressing member 69, and the front and back surfaces of the sheet member 68, respectively. A structure is disclosed.

Patent Document 2 below discloses a seal structure in which a hard sheet and a soft sheet are press-fitted in a groove for mounting a sheet.
Japanese Patent Laid-Open No. 11-201295 JP-A-62-228764

  When the valve body 64 is opened and the fluid is flowing, the seat member 68 is exposed to the fluid, and when a high differential pressure is generated between the upstream side and the downstream side of the seat member 68, the virtual member of FIG. As indicated by the line, there is a possibility that the sheet member 68 may be pulled out to the outer peripheral side larger than the predetermined amount A. Thus, if the seat member 68 comes out, there is a problem that the sealing performance of the valve cannot be secured.

  As a measure for preventing the sheet member 68 from slipping out, the groove portion 71 is formed in each of the pressing surfaces 67a and 69a as described above, thereby improving the resistance to the sheet member 68 from slipping out. However, even if the groove portion 71 is formed, it is insufficient to prevent the sheet member 68 from coming off.

  Further, as another countermeasure, it is conceivable to improve the resistance against the withdrawal of the sheet member 68 by inserting a steel cored bar inside the sheet member 68. However, there is a problem that the cost of the mold and the manufacturing cost of the sheet member 68 are significantly increased.

  As another countermeasure, the tightening force of the bolt 70 is increased, and as shown in FIG. 13, the pressing force F (compressing force) when the sheet presser 69 presses and compresses the sheet member 68 is increased. The rebound resilience of the member 68 is improved, and the resistance force against the withdrawal of the sheet member 68 is improved. However, normally, the compression rate of the sheet member 68 is about 10% of the thickness. However, when the compression rate is increased to about 20% by increasing the pressing force F as described above, the sheet member 68 is increased. There is a problem that the outer peripheral edge of the lens is deformed from a circular shape to a distorted shape.

  In order to prevent such deformation of the seat member 68, when the seat member 68 having a high rubber hardness is used, the deformation of the seat member 68 is suppressed and the opening / closing torque of the valve body 64 increases. There is a problem that the durability of the member 68 is inferior.

Further, the seal structure disclosed in Patent Document 1 is insufficient to prevent the sheet member from slipping out, similarly to the seal structure shown in FIG.
Further, with respect to the seal structure disclosed in Patent Document 2, the hard sheet and the soft sheet are overlapped but are different from each other, and the soft sheet is freely movable with respect to the hard sheet. And the soft sheet are compressed by the sheet presser, the soft sheet may be deformed into a distorted shape, and there is a problem that the sealing performance cannot be secured.

  The present invention can sufficiently prevent the sheet member from coming out while preventing the deformation of the sheet member accompanying an increase in the pressing force of the sheet presser, and can prevent a significant increase in cost. It is another object of the present invention to provide a valve seal structure capable of preventing an increase in opening / closing torque and a deterioration in durability of a seat member.

In order to achieve the above object, the first invention is a valve seal structure provided at a location exposed to a fluid flow in a valve box and sealing between a movable member and a fixed member in the valve box. And
An annular sheet member made of an elastic body is provided in a sheet holding part formed on at least one of a movable member or a fixed member,
The sheet member is sandwiched and fixed from both sides by the sheet presser and the sheet holding part,
The sheet member is configured by integrally joining a soft part having a low hardness and a hard part having a higher hardness than the soft part,
The hard part has a surface pressed by the sheet presser,
The soft portion is in sliding contact with either the movable member or the fixed member when the movable member moves to a predetermined position.

  According to this, when the pressing force (compression force) of the sheet presser is increased in order to improve the resistance against the slipping out of the sheet member, the hard portion of the sheet member has higher hardness than the soft portion, and thus Difficult to deform against pressure. Here, since the soft portion and the hard portion are integrally coupled, the soft portion is constrained by the hard portion and is difficult to deform, thereby preventing the deformation of the sheet member accompanying the increase in the pressing force. Since the resistance against the slipping out of the sheet member can be improved, the slipping out of the sheet member against a high differential pressure can be sufficiently prevented.

In addition, the cost can be reduced as compared with a configuration in which a core metal is placed inside a conventional sheet member.
Further, when the movable member moves to a predetermined position, the soft portion of the sheet member comes into sliding contact with the other member, so that an increase in torque required to move the movable member can be suppressed.

The second invention is a valve body in which the movable member is rotatable about the axis of the valve stem and opens and closes the flow path in the valve box.
The fixing member is a valve seat side valve seat provided in the valve box,
The sheet member is provided in a sheet holding part formed on the peripheral edge of the valve body, and is clamped and fixed from both sides by the sheet presser and the sheet holding part,
The soft portion slides on the valve box side valve seat when the valve body rotates to the closed position.

  According to this, when the valve body rotates to the closed position, the soft portion of the seat member comes into sliding contact with the valve box side valve seat portion, so that the soft portion is easily compressed and deformed during sliding contact. Thereby, an increase in torque required to open and close the valve body can be suppressed.

  As described above, according to the present invention, it is possible to improve the resistance against the sheet member being pulled out while preventing the deformation of the sheet member due to an increase in the pressing force. Can be prevented.

In addition, the cost can be reduced as compared with a configuration in which a core metal is placed inside a conventional sheet member.
Moreover, an increase in torque required to open and close the valve body can be suppressed.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, reference numeral 1 denotes an eccentric butterfly valve that is an example of a valve. Inside the valve box 2, a valve body 4 (an example of a movable member) that opens and closes the flow path 3 is a valve rod 5. It is provided so as to be rotatable around the shaft center. Further, the valve box 2 has an annular valve box side valve seat portion 7 (an example of a fixing member) on the inner peripheral surface.

A seal structure for sealing between the valve body 4 and the valve box side valve seat portion 7 is configured as follows.
As shown in FIGS. 3 to 5, a seat holding portion 8 is formed on the outer peripheral edge of the valve body 4 over the entire circumference, and an annular seat member 9 is provided on the seat holding portion 8. ing.

  The sheet member 9 is sandwiched and fixed from both front and back sides by an annular sheet presser 10 and a sheet holding portion 8. The opposing surfaces of the sheet holding portion 8 and the sheet presser 10 are formed as presser surfaces 8 a and 10 a, respectively, and these presser surfaces 8 a and 10 a are in contact with both the front and back surfaces of the sheet member 9. The sheet presser 10 is attached to the valve body 4 by a plurality of bolts 11. As shown in FIG. 3, when the seat member 9 is attached, the outer peripheral edge of the seat member 9 protrudes by a predetermined amount A to the outside in the radial direction from the outer peripheral edges of the valve body 4 and the sheet presser 10. .

  Further, as shown in FIG. 4, the pressing surface 8a of the sheet holding portion 8 and the front and back surfaces 9a of the sheet member 9 that abuts against the pressing surface 8a are engaged with each other in a cross-sectional wave shape that is engaged in the radial direction. A plurality of one convex portion 14 (an example of a first engaging portion) and a first concave portion 15 (an example of a first engaged portion) are formed. Similarly, a second convex portion 16 (first shape) having a corrugated cross-sectional shape that engages in the radial direction between the presser surface 10a of the sheet presser 10 and the other surface 9b of the sheet member 9 that contacts the presser surface 10a. A plurality of second engagement portions) and a plurality of second recesses 17 (one example of second engagement portions) are formed.

  Further, a protrusion 18 (an example of a third engaging portion) is formed on the inner peripheral edge of the other surface 9b of the sheet member 9, and a fitting portion is formed on the inner peripheral edge of the pressing surface 10a of the sheet presser 10. 19 (an example of a third engaged portion) is formed, and the protruding portion 18 is fitted into the fitting portion 19.

Further, a plurality of bolt holes 21 are formed in the sheet member 9, and the bolts 11 are inserted through these bolt holes 21.
The sheet member 9 is made of two types of rubber (an example of an elastic body) having different hardness, and the soft layer 23 (an example of a soft part) and the hard layers 24a and 24b (an example of a hard part) are integrally molded. It has a three-layer structure. A pair of the hard layers 24a and 24b are formed in the thickness direction of the sheet member 9, and the soft layer 23 is sandwiched between the pair of hard layers 24a and 24b and integrally coupled.

  The hardness of the hard layers 24a and 24b is higher than the hardness of the soft layer 23. For example, the hardness of the hard layers 24a and 24b is set to be about 10 to 20% higher than the hardness of the soft layer 23. As a more specific example, the hardness of the soft layer 23 is set to about Hs70, and the hardness of the hard layers 24a and 24b is set to about Hs80. These numerical values are merely examples, and are not limited. The soft layer 23 only needs to have a hardness sufficient to ensure a sealing pressure, and the hard layers 24a and 24b can only prevent slipping out. What is necessary is just to have the hardness of.

  One hard layer 24 a is in contact with the pressing surface 8 a of the sheet holding portion 8, and the other hard layer 24 b is in contact with the pressing surface 10 a of the sheet pressing 10. Moreover, the 1st convex part 14 is formed in one hard layer 24a, and the 2nd convex part 16 and the projection part 18 are formed in the other hard layer 24b.

Further, as shown in FIG. 5, the outer peripheral edge of the soft layer 23 is configured to come into sliding contact with the valve box side valve seat portion 7 when the valve body 4 rotates to the closed position S (an example of a predetermined position). Yes.
Hereinafter, the operation of the above configuration will be described.

  When the valve body 4 is opened and a fluid such as water is flowing, the seat member 9 is exposed to the fluid, and a high differential pressure may be generated between the upstream side and the downstream side of the seat member 9. In order to prevent the sheet member 9 from slipping out against such a high differential pressure, it is necessary to improve resistance to the sheet member 9 from slipping out. In order to improve this resistance, when the tightening force of the bolt 11 is increased and the pressing force F (compression force) of the sheet presser 10 is increased as shown in FIG. 3, the hard layers 24a and 24b of the sheet presser 10 are Since the hardness is higher than that of the soft layer 23, it is difficult to be deformed with respect to the pressing force F. Here, since the soft layer 23 and the hard layers 24a and 24b are integrally coupled, the soft layer 23 is constrained from both sides by the hard layers 24a and 24b, and is not easily deformed. Since it is possible to improve the resistance against the slipping out of the sheet member 9 while preventing the deformation of the sheet member 9 due to the increase in the sheet member 9, it is possible to sufficiently prevent the sheet member 9 from slipping out against a high differential pressure.

In addition, the cost can be reduced as compared with a configuration in which a core metal is placed inside a conventional sheet member.
As shown in FIG. 5, when the valve body 4 rotates to the closed position S, the outer peripheral edge of the soft layer 23 of the seat member 9 is in sliding contact with the valve box side valve seat portion 7. The outer peripheral edge is easily compressed and deformed. Thereby, an increase in torque required to open and close the valve body 4 can be suppressed.

  Further, as shown in FIG. 3, the first convex portion 14 and the first concave portion 15 are engaged, the second convex portion 16 and the second concave portion 17 are engaged, and the protruding portion. Since 18 is fitted in the fitting part 19, the resistance force against the withdrawal of the sheet member 9 can be further improved.

  In the first embodiment, the sheet member 9 has a three-layer structure including the soft layer 23 and the hard layers 24a and 24b. However, the sheet member 9 has a two-layer structure including the soft layer 23 and the hard layer 24b. Good. The hard layer 24b has a surface 9b pressed by the sheet presser 10. Alternatively, a plurality of layers having a four-layer structure or more may be used.

  In the first embodiment, the soft layer 23 and the hard layers 24a and 24b are adjacent in the thickness direction of the sheet member 9, but may be adjacent in the radial direction. One example of this will be described with reference to FIGS. 6 and 7 in the second embodiment described below.

  That is, the sheet member 9 has a two-layer structure in which a soft layer 23 (an example of a soft part) and a hard layer 24 (an example of a hard part) are integrally molded. The inner peripheral edge of the soft layer 23 and the outer peripheral edge of the hard layer 24 are integrally coupled, and the hard layer 24 is sandwiched between the pressing surface 8a of the sheet holding portion 8 and the pressing surface 10a of the sheet pressing member 10. Yes.

The first convex portion 14 is formed on the front and back surfaces 9 a of the hard layer 24, and the second convex portion 16 and the protrusion 18 are formed on the front and back surfaces 9 b of the hard layer 24.
According to this, when the tightening force of the bolt 11 is increased and the pressing force F (compression force) of the sheet presser 10 is increased in order to improve the resistance force against the slipping out of the sheet member 9, the hard layer 24 of the sheet presser 10. Since the hardness is higher than that of the soft layer 23, it is difficult to be deformed with respect to the pressing force F. Accordingly, it is possible to improve the resistance against the withdrawal of the sheet member 9 while preventing the deformation of the sheet member 9 due to the increase in the pressing force F, so that the withdrawal of the sheet member 9 against the high differential pressure is sufficiently prevented. be able to.

  Further, as shown in FIG. 7, when the valve body 4 rotates to the closed position S, the soft layer 23 of the seat member 9 is in sliding contact with the valve box side valve seat portion 7, so that the soft layer 23 is easy to slide during sliding contact. Compressed and deformed. Thereby, an increase in torque required to open and close the valve body 4 can be suppressed.

  In the said 1st and 2nd embodiment, although the sheet | seat holding | maintenance part 8 is formed in the valve body 4, and the sheet | seat member 9 is provided in this sheet | seat holding | maintenance part 8, as FIG. As shown in FIG. 10, a seat holding portion 8 may be formed on the valve box side valve seat portion 7, and a seat member 9 may be provided on the seat holding portion 8.

  That is, as shown in FIG. 10, the seat holding portion 8 is formed on the inner peripheral edge portion of the valve box side valve seat portion 7 over the entire circumference. The seat presser 10 is attached to the valve box side valve seat portion 7 by a plurality of bolts 11. In the state where the seat member 9 is attached, the inner peripheral edge of the seat member 9 protrudes inward in the radial direction by a predetermined amount A from the inner peripheral edges of the valve box side valve seat portion 7 and the seat presser 10. As shown in FIG. 9, the inner peripheral edge of the soft layer 23 is configured to come into sliding contact with the outer peripheral edge of the valve body 4 when the valve body 4 rotates to the closed position S (an example of a predetermined position). .

  According to this, it is possible to improve the resistance against the slipping out of the sheet member 9 while preventing the deformation of the sheet member 9 due to the increase in the pressing force F, and thus sufficiently prevent the sheet member 9 from slipping out against a high differential pressure. can do.

  Further, as shown in FIG. 9, when the valve body 4 rotates to the closed position S, the inner peripheral edge of the soft layer 23 of the seat member 9 is in sliding contact with the outer peripheral edge of the valve body 4. The inner peripheral edge of the tube is easily compressed and deformed. Thereby, an increase in torque required to open and close the valve body 4 can be suppressed.

  Further, as a fourth embodiment, as shown in FIG. 11, sheet holding portions 8 are formed in both the valve body 4 and the valve box side valve seat portion 7, and the seat holding portions 8 are respectively seated. The member 9 may be provided. In this case, when the valve body 4 rotates to the closed position S, the outer peripheral edge of the soft layer 23 of the seat member 9 provided on the valve body 4 side is the softness of the seat member 9 provided on the valve box side valve seat portion 7 side. It is in sliding contact with the inner periphery of the layer 23.

  In the said 3rd and 4th embodiment, although the sheet member 9 of the three-layer structure in 1st embodiment is used, it uses the sheet member 9 in 2nd embodiment shown in FIG. Also good.

  In each of the above embodiments, as an example of the valve, as shown in FIG. 1, the eccentric butterfly valve 1 in which the position of the valve stem 5 is shifted from the seal surface has been described, but an eccentric butterfly valve may be used, Alternatively, other types of valves other than the butterfly valve may be used.

  In each of the embodiments described above, water is exemplified as an example of the fluid, but a liquid or gas other than water may be used.

It is a cross-sectional view of the eccentric butterfly valve in the first embodiment of the present invention. It is a front view of an eccentric butterfly valve. It is an expanded sectional view of the outer periphery part of the valve body which shows the sealing structure of an eccentric butterfly valve. It is an exploded sectional view of the seal structure of an eccentric butterfly valve. It is an expanded sectional view showing a seal structure when the valve element of an eccentric butterfly valve is in a closed position. It is a disassembled sectional view of the seal structure of the eccentric butterfly valve in 2nd embodiment of this invention. It is an expanded sectional view showing a seal structure when the valve element of an eccentric butterfly valve is in a closed position. It is a cross-sectional view of the eccentric butterfly valve in the third embodiment of the present invention. It is an expanded sectional view showing a seal structure when the valve element of an eccentric butterfly valve is in a closed position. It is an exploded sectional view of the seal structure of an eccentric butterfly valve. It is an expanded sectional view showing the seal structure when the valve element of the eccentric butterfly valve in the fourth embodiment of the present invention is in the closed position. It is a cross-sectional view of a conventional eccentric butterfly valve. It is an expanded sectional view of the outer periphery part of the valve body which shows the sealing structure of an eccentric butterfly valve. It is an exploded sectional view of the seal structure of an eccentric butterfly valve. It is an expanded sectional view showing a seal structure when the valve element of an eccentric butterfly valve is in a closed position.

Explanation of symbols

1 Eccentric butterfly valve (valve)
2 Valve box 3 Flow path 4 Valve body (movable member)
5 Valve stem 7 Valve seat side valve seat (fixed member)
8 Sheet holding part 9 Sheet member 10 Sheet presser 23 Soft layer (soft part)
24, 24a, 24b Hard layer (hard part)
S Closed position (predetermined position)

Claims (2)

A seal structure of a valve provided at a location exposed to the fluid flow in the valve box and sealing between a movable member and a fixed member in the valve box;
An annular sheet member made of an elastic body is provided in a sheet holding part formed on at least one of a movable member or a fixed member,
The sheet member is sandwiched and fixed from both sides by the sheet presser and the sheet holding part,
The sheet member is configured by integrally joining a soft part having a low hardness and a hard part having a higher hardness than the soft part,
The hard part has a surface pressed by the sheet presser,
The soft part is in a valve seal structure characterized in that when the movable member moves to a predetermined position, the soft portion is in sliding contact with either the movable member or the fixed member. The movable member is a valve element that can rotate around the axis of the valve stem and opens and closes the flow path in the valve box.
The fixing member is a valve seat side valve seat provided in the valve box,
The sheet member is provided in a sheet holding part formed on the peripheral edge of the valve body, and is clamped and fixed from both sides by the sheet presser and the sheet holding part,
The valve sealing structure according to claim 1, wherein the soft portion is in sliding contact with the valve seat side valve seat portion when the valve body rotates to the closed position.

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