JP6508804B2 - Double eccentric type butterfly valve - Google Patents

Description

  The present invention relates to a butterfly valve which is provided in a pipeline or the like through which a fluid such as water flows, and which can be opened and closed by a valve element which opens and closes by rotating around a valve rod. .

  In general, a butterfly valve controls a fluid by controlling an on-off valve by rotating a disc-like valve body in a flow path of a short cylindrical valve box. In particular, a butterfly valve having a double eccentric structure has a configuration in which the center of the valve stem is offset from the center of the seat ring and also in the thickness direction of the valve body. The double eccentric type butterfly valve can prevent the wear of the sealing surface of the valve body because the valve body disengages from the seat ring at a slight rotation angle by the cam action by the eccentricity when the valve body is opened. There is an advantage that it is not greatly affected by fluid pressure. Moreover, the valve seat sealability is superior to that of a center disk type butterfly valve which is not eccentric.

  As such a double eccentric type butterfly valve, for example, the one described in Patent Document 1 is known. In this butterfly valve, a stainless steel seat ring is provided all around the inner peripheral surface of the valve box, and the valve seat contact surface of the seat ring is a tapered surface whose diameter increases toward the upstream side of the flow path Is formed. A disc-shaped metal valve body that can be opened and closed with respect to the seat ring can be opened and closed around the valve rod, and an annular lining material made of synthetic rubber and having a convex cross-sectional shape is made of synthetic rubber over the entire outer peripheral portion of the valve body. It is integrally molded as a seat. The annular lining material of the valve body is considered to be difficult to be peeled off from the valve body even when a large torque is applied, since the connecting pin constituting a part thereof intrudes into the connecting hole of the outer peripheral portion of the valve body.

  As another example, a double eccentric butterfly valve shown in FIG. 5 is known. In the butterfly valve 1, the valve box valve seat 3 provided in the flow passage 4 in the valve case 2 is formed with a tapered surface 3 a so as to expand in diameter on the upstream side of the flow passage 4. The valve body 5 which is rotatable around the valve rod and opens and closes the valve box valve seat 3 has a synthetic rubber valve seat 6 mounted on the entire circumference in a recessed groove portion formed on the outer peripheral surface of the disk shape. Then, the valve seat 6 of the valve body 5 has a tip end 6a tapered in a trapezoidal shape in a cross-sectional view, and the tip end 6a is closed by pressing against the tapered surface 3a of the valve seat 3 , Will stop the water.

  In FIG. 5, the hatched portion of the tip 6a of the valve seat 6 is a penetration amount, and the point of intersection of the center line O in the thickness direction (width direction) of the valve body 5 and the tip 6a is E. The torque F in the rotational direction of the valve body 5 at the intersection E of the rotational axis L passing through the intersection E of the tip 6a of the valve seat 6 from the center of the rod is orthogonal to the rotational axis L, the tapered surface 3a of the valve box valve seat 3 It occurs in the direction along the

JP, 2011-7313, A

However, in the valve body described in Patent Document 1 and the valve body 5 shown as another example, the ring-lined valve seat or the valve body 5 is desired to be additionally tightened so that, for example, water leakage does not occur in the valve closed state. Since the torque F works along the direction in which the tapered surface 3a extends, even if the tip 6a of the valve seat 6 is closed with the valve stem as the center and the valve ring 3 is pressed against the seat 3 There is a drawback that the seal strength due to the valve closing is not strong and it can not be tightened again. In addition, even if the annular lining valve seat and the tip 6a of the valve seat 6 are worn by repeated use, the penetration into the seat ring and the valve box valve seat 3 becomes small, and retightening can be performed in the same manner. It was not.
In such a case, the position adjustment and design change of the seat ring and the valve box valve seat 3 or the replacement of the valve body are dealt with, and there is a drawback that the process is complicated and time consuming, and the cost is high.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a double eccentric butterfly valve which can suppress a cost increase and can be tightened with a simple configuration.

In the double eccentric butterfly valve according to the present invention, the center line (P) of the valve stem which is the rotation center of the valve disc is eccentric from the center line (M) of the valve box and the center line of the flow path of the valve box In the double eccentric type butterfly valve eccentric from N), the valve seat of the valve disc is eccentrically positioned on the diameter expansion side of the tapered surface of the valve box with respect to the center line (O) in the thickness direction of the valve seat. A contact portion is formed, and the valve seat of the valve body is tapered at both ends in the thickness direction in a radial cross-sectional view so that the contact portion is tapered and the valve body is The contact portion is pressed in a direction intersecting with the tapered surface of the valve box by rotation of the valve body, and a torque acts in a direction to bite into the tapered surface to close the valve.
According to the double eccentric type butterfly valve according to the present invention, the valve seat of the valve body is eccentric to the diameter expansion side of the tapered surface of the valve box valve seat at the time of closing the valve with respect to the center line (O) in the thickness direction Since the contact part is formed on the valve stem, when the valve stem is rotated and closed, the valve element has the cam action by double eccentricity, and the contact part of the valve seat covers the entire taper surface of the valve seat. The contact portion provided at the eccentric position of the valve seat contacts the entire circumference by the self-aligning function of the tapered surface of the valve seat. Further, the torque (F) acts in a direction in which it penetrates into the tapered surface of the valve seat, whereby the contact portion of the valve body can be crimped and sealed to the tapered surface of the valve seat. And, since the contact portion of the valve seat is eccentric to the enlarged diameter side of the tapered surface of the valve box with respect to the center line (O), when the valve body is tightened again, the contact portion is further It can penetrate into the tapered surface and seal with higher strength.

Moreover, by forming the contact portion of the valve seat of the valve body in a tapered shape, the elastically deformable bite margin is large, and when it is tightened again, it is further pressed by the tapered surface of the valve box valve seat and compressed and deformed. Because it seals to, you can do retightening securely.

Further, it is preferable that the tapered surface of the valve box valve seat be formed so as to expand in diameter upstream or downstream of the flow path of the valve box.
The contact surface of the valve seat of the valve body abuts against the tapered surface of the valve box and the seat is compressed and sealed with high strength, so that retightening can be reliably performed.

  According to the double eccentric type butterfly valve according to the present invention, the contact portion of the valve seat of the valve body, which abuts against the valve seat, corresponds to the center line in the thickness direction of the valve seat of the valve body. Since the valve box is installed eccentrically on the diameter expansion side of the tapered surface, it is possible to retighten the valve box valve seat, and even if the valve seat of the valve body is worn out, it is inserted into the valve box valve seat to ensure retightening Can be done.

FIG. 5 is a front view of a dual eccentric butterfly valve according to an embodiment of the present invention. It is an AA line horizontal sectional view of the double eccentric type butterfly valve shown in FIG. It is a BB line longitudinal cross-sectional view of the double eccentric type butterfly valve shown in FIG. It is an expanded sectional view of the C section and the D section which show the valve closing state of the valve body shown in FIG. It is principal part sectional drawing which shows the valve closing state of the conventional valve body.

Hereinafter, a dual eccentric type butterfly valve according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.
The butterfly valve 10 shown in FIG. 1 and FIG. 2 is provided in a pipeline for flowing liquid, for example, water such as water supply, and shows, for example, a horizontal butterfly valve. In FIG. 1, the butterfly valve 10 includes a leg portion 11 and a valve box 13 having a cylindrical flow passage 12 therein, and a valve body 14 capable of opening and closing the flow passage 12 in the valve case 13 There is. A flange portion 13a is formed on the outer peripheral side of the valve box 13, and connection holes 13b are formed at predetermined intervals in the circumferential direction. At the left and right positions sandwiching the flow path 12 in the valve box 13, valve rods 17A and 17B rotatably supported by bearings 16 are horizontally disposed.

  The valve body 14 has a disk shape, and is connected by pins via left and right valve rods 17A, 17B via a connecting plate 18, and can be rotated about a horizontal axis centering on a center line P of the valve rods 17A, 17B. It is done. The valve rods 17A and 17B are separated from each other and disposed on the outer side from near both ends of the inner peripheral surface 20 of the valve box 13 and have a common center line P.

  Further, in FIG. 3 and FIG. 4, the inner circumferential surface 20 forming the flow passage 12 in the valve box 13 is a cylindrical shape whose inner diameter changes, and the ring-shaped convex portion is entirely at the middle portion in the central axis N direction. Formed around the periphery, this convex portion forms a valve box valve seat 21. The valve box valve seat 21 of the inner circumferential surface 20 has, for example, a tapered surface 21a whose diameter gradually decreases from the upstream side to the downstream side of the flow passage 12 shown in FIG. A cylindrical surface 21b of a diameter is formed. In the present embodiment, when the valve box 21 is viewed in the direction of the central axis N of the flow passage 12, the ratio of the length of the tapered surface 21a to the length of the cylindrical surface 21b is set to, for example, about 2: 1. The valve box valve seat 21 can be opened and closed by a valve body 14 rotatable around valve rods 17A and 17B.

  The valve stems 17A and 17B are eccentrically deviated in the radial direction from the central axis N of the flow path 12 of the valve box 13 as shown in FIGS. 1 to 3 and moreover the center line of the valve box valve seat 21 It has a double eccentric structure which is offset from M and eccentric (or eccentric in the thickness direction of the valve body 14). Therefore, the butterfly valve 10 according to the present embodiment is a double eccentric butterfly valve.

  Further, in FIG. 4, the valve body 14 is formed in a disk shape, and a groove 23 opened to the outside is formed on the outer peripheral surface over the entire circumference, and the groove 23 is an opening with a large diameter recess 23 a on the back side It is formed by the small diameter recessed part 23b of the side. Further, a valve seat 24 of synthetic rubber, for example, is fitted as an elastic member in the groove 23 of the valve body 14. In the cross-sectional view shown in FIG. 4, the tip on the outer peripheral side of the valve seat 24 has substantially the same inclination angle θ1 as the tapered surface 21 a of the valve box valve seat 21 and abuts on the tapered surface 21 a The contact portion 25 closing the valve, the first tapered surface 26 provided on the downstream side of the contact portion 25 and having an inclination angle θ2 larger than the contact portion 25 and the upstream side of the contact portion 25 And a second tapered surface 27 having an inclination angle θ3 steeply inclined in the opposite direction. Therefore, the contact portion 25 is formed to be tapered or trapezoidal in cross section.

Moreover, the valve seat 24 is eccentric to the upstream side of the center line O with respect to the intersection point E of the center line O in the thickness direction (width direction) and the contact portion 25 of the valve seat 24 as in the prior art described above. The contact portion 25 is formed at the position where In other words, the contact portion 25 of the valve seat 24 is formed eccentrically to the center line O on the enlarged diameter side of the tapered surface 21a of the valve seat 21 at the time of valve closing. And the hatching part of the predetermined thickness of the contact part 25 is the penetration allowance.
Therefore, since the contact portion 25 is provided on the upstream side with respect to the center line O in the thickness direction of the valve seat 24, a direction orthogonal to the rotation axis L connecting the intersection E from the center line P of the valve rods 17A and 17B. The torque F in the valve closing direction acting on the contact portion 25 acts on the tapered surface 21 a of the valve seat 21 against the torque in the valve closing direction in the prior art. Therefore, when the contact portion 25 of the valve body 14 is further rotated in the valve closing direction around the valve rods 17A and 17B, the contact portion 25 is further pushed into the tapered surface 21a and can be tightened.
The valve seat 24 and the valve box valve seat 21 of the valve body 14 shown in FIG. 4 are all in line symmetry with respect to the center line of the valve body 14 and the center line N of the flow path 12 in FIG. It is formed over the circumference.

The biaxially offset type butterfly valve 10 according to the present embodiment has the above-described configuration, and its operation will be described next.
In the biaxial eccentric type butterfly valve 10, when the valve body 14 is opened through the valve operation shaft or the gear box by operating the handle (not shown), the center line P of the valve rods 17A and 17B is Because of the double eccentricity deviated from the center line N and the thickness center of the valve body 14, in FIG. 3, the cam action by the double eccentricity causes the valve box 21 to deviate from the valve seat 21 by a slight rotation angle in the valve opening direction. . Therefore, the fluid flowing into the inner circumferential surface 20 of the valve box 13 flows through the flow path 12 through the openings of the valve body 14 and the valve box valve seat 21.

  When the valve rods 17A and 17B are rotated in the valve closing direction when closing the valve body 14, in FIG. 4, the valve seat 24 provided on the peripheral portion of the valve body 14 by the cam action by double eccentricity. The contact portion 25 abuts on the tapered surface 21 a of the valve box 21 along the entire circumference to close the valve. In particular, when the flow path 12 is sealed by the valve body 14 closing the valve, the contact portion 25 provided at the eccentric position of the width direction center line O of the valve seat 24 automatically aligns the tapered surface 21 a of the valve box valve seat 21 Uniformly contact over the entire circumference. Further, the torque F in the valve closing direction works, so that the contact portion 25 of the valve body 14 can be sealed because it penetrates into the tapered surface 21 a of the valve box valve seat 21.

  Even in this state, when the sealing function between the valve body 14 and the valve box valve seat 21 is not sufficient, the valve rod 17A, 17B is further rotated in the valve closing direction, the contact portion 25 of the valve body 14 However, since the torque F further works toward the tapered surface 21a of the valve box valve seat 21, the contact portion 25 is compressed and elastically deformed to be more strongly crimped, so that it is possible to retighten.

As described above, according to the biaxially offset type butterfly valve 10 according to the present embodiment, the contact portion 25 of the outer peripheral portion of the valve body 14 with respect to the center line O of the valve seat 24 in the thickness direction Since the eccentricity is made on the enlarged diameter side of the tapered surface 21 a 21, when the valve is further tightened after closing the valve, the torque F squeezes the contact portion 25 in the direction of pressing the tapered surface 21 a of the valve seat 21 Higher pressure seals can be achieved. In addition, since retightening can be performed without deforming the shape of the valve box and the like, the cost increase can be suppressed.
In addition, even if the contact portion 25 of the valve seat 24 in the valve body 14 is worn by repeated use and the amount that can be inserted is reduced, the contact portion 25 is the center of the valve seat 24 in the thickness direction. Since it is formed to be eccentric with respect to the line O, it is possible to make a higher seal by making the tapered surface 21a of the valve box valve seat 21 go into by the additional tightening.

  The present invention is not limited to the butterfly valve 10 according to the above-described embodiment, and appropriate changes, substitutions, and the like can be made without departing from the scope of the present invention, and any of them is included in the present invention. . Hereinafter, although the modification of the present invention is explained, the same numerals are used to the same or similar parts and members as the above-mentioned embodiment, and explanation is omitted.

For example, in the embodiment described above, in FIGS. 3 and 4, the diameter expansion side of the tapered surface 21 a of the valve box valve seat 21 is the upstream side in FIGS. 3 and 4. Conversely, the diameter reducing side of the tapered surface 21a may be upstream. In this case, the contact portion 25 of the valve body 14 is eccentrically disposed on the downstream side of the flow passage 12 with respect to the center line O in the thickness direction of the valve seat 24. Even in this case, the valve body 14 can be fitted into the tapered surface 21 a of the valve box valve seat 21 when the valve is closed, as in the above-described embodiment, to be additionally tightened.
In the embodiment described above, the contact portion 25 formed at the tip of the valve seat 24 of the valve body 14 is formed in a trapezoidal or tapered cross section, but the cross sectional shape of the contact portion 25 is limited to a trapezoidal shape. Rather than the above, it is possible to adopt an appropriate shape such as a convex curve shape, a triangle shape, or a quadrangle shape in cross section.

In the embodiment described above, the convex portion is formed on the entire circumference of the inner circumferential surface 20 of the valve box 13 to form the valve box valve seat 21. However, instead of this, the inner circumferential surface 20 of the valve box 13 is recessed. A groove may be formed, and a metal seat ring, for example, may be disposed in the recessed groove to form an inclined seal surface to which the contact portion 25 of the valve body 14 can abut on the inner surface. The seal ring is also included in the valve box valve seat of the valve box 13.
Although the double eccentric type butterfly valve according to the present invention has been described as a butterfly valve in which the valve rods 17A and 17B are horizontal, the present invention is not limited to such a form, and the valve rods 17A and 17B are vertically It may be a vertical butterfly valve arranged separately in the direction.

DESCRIPTION OF SYMBOLS 10 Butterfly valve 12 Flow path 13 Valve box 14 Valve body 17A, 17B Valve rod 21 Valve box valve seat 21a Taper surface 24 Valve seat 25 Contact part P Center line M of valve stem Center line N of valve box valve seat Flow path Center line O Center line in the width direction of the valve seat

Claims (2)

In a double eccentric butterfly valve in which the center of the valve rod which is the rotation center of the valve body is eccentric from the center of the valve box and from the center line of the flow path of the valve box,
In the valve seat of the valve body, a single contact portion is formed at a position eccentric to the diameter expansion side of the tapered surface of the valve box valve seat with respect to the center line in the thickness direction thereof,
In the valve seat of the valve body, both ends in the thickness direction are cut in a tapered shape in a radial sectional view, and the contact portion is formed in a tapered shape.
In the valve body, the contact portion of the valve seat is pressed in a direction crossing the tapered surface of the valve box valve seat by the rotation of the valve body, and a torque acts in a direction to bite into the tapered surface. Double eccentric type butterfly valve characterized by having.   The double eccentric type butterfly valve according to claim 1, wherein the tapered surface of the valve box valve seat is formed to expand in diameter upstream or downstream of the flow passage of the valve box.

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