JP3650059B2 - Butterfly valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a butterfly valve that opens and closes a flow path with a plate-like valve body.
[0002]
[Prior art]
In water supply / drainage, air conditioning equipment, various industrial plants, factory processes, and the like, butterfly valves, which are valve devices that control the flow of fluid by the rotation of a disc-shaped valve body, are widely used.
[0003]
In this butterfly valve, the valve body is fixed to a valve rod rotatably attached to the housing, and in order to obtain a predetermined valve opening such as full open, full close, intermediate opening, Further, a valve body drive unit such as a gear or a lever is provided. And in order to hold | maintain the set valve opening, the valve body drive part is provided with the lock mechanism.
[0004]
However, if the inside of the pit where the valve is placed is narrow and there is no space for mounting the valve body drive part, if the valve is not operated incorrectly, or if the valve is not opened and closed frequently, the valve such as a gear or lever No body drive is provided. In this case, the set valve opening is maintained by locking the rotation of the valve stem.
[0005]
As a means for this locking, there is a locking mechanism using a ball plunger.
[0006]
Here, FIG. 11 shows a lock mechanism in a conventional butterfly valve.
[0007]
As shown in the figure, the conventional locking mechanism using the ball plunger is attached to the valve stem 113 so that the ball displacement direction is the same as the axial direction of the valve stem 113 and rotates around the rotation axis of the valve stem 113. A locking portion 120 provided with a ball plunger 119 and a disk-shaped flange 121 provided in the housing 112 with a lock hole 120a engageable with the ball of the ball plunger 119 formed on the rotation locus of the ball plunger 119. Become. The lock hole 120a is formed at a position where the valve body 114 has a desired valve opening when the lock hole 120a and the ball plunger 119 are engaged with each other.
[0008]
Here, the further away the ball plunger 119 is from the valve stem 113, the greater the locking force, that is, the holding force of the valve body 114.
[0009]
Therefore, in the above-described conventional technology, when the ball plunger 119 is attached to a location away from the valve stem 113 to such an extent that a desired locking force can be obtained, the lock hole 120a that engages with the ball plunger 119 is also separated from the valve stem 113. Must be formed in place.
[0010]
[Problems to be solved by the invention]
However, if the lock hole is installed at a location away from the valve stem so that a sufficient locking force can be obtained, the flange itself provided with such a lock hole becomes large. This is not preferable because the butterfly valve itself increases in size. Further, since the flange 121 has a problem in connecting the valve and the piping unless the size is within the face-to-face dimension of the butterfly valve, there are restrictions in size and shape even if the flange is enlarged. .
[0011]
Here, the butterfly valve includes an eccentric valve type in which a valve element is attached eccentrically from the rotating shaft of the valve stem. In the case of an eccentric valve, when the valve body is inclined at an angle of 0 ° with respect to the fluid flow direction, the valve is set at the fully open position, and is located downstream in the fluid flow direction in the valve body and on the axial center side of the flow path. A negative pressure portion is generated and a force to displace the valve body to the closed position, that is, an unbalance torque is generated.
[0012]
In such an eccentric valve, if a sufficient locking force is obtained by the above-described locking mechanism, the butterfly valve is increased in size. Further, when trying to avoid an increase in the size of the butterfly valve, the flange provided with the lock hole becomes small, and the locking force of the ball plunger becomes weak. Then, when the flow rate increases and the unbalance torque increases, the ball plunger may be unlocked and the valve body may be fully closed, closing the flow path.
[0013]
In order to solve such a problem, for example, Japanese Utility Model Publication No. 2-29324 and Japanese Utility Model Publication No. 3-53089 disclose a technology for generating a lift force that cancels an unbalance torque by attaching a fin to a valve body. Yes.
[0014]
However, although these techniques are effective for countermeasures against unbalanced torque at an intermediate opening, no consideration is given at the time of full opening, and even if these techniques are applied at the time of full opening, the problem of unbalanced torque is not solved.
[0015]
Then, an object of this invention is to provide the butterfly valve which can provide sufficient locking force to a latching | locking part, without enlarging an apparatus.
[0016]
It is another object of the present invention to provide a butterfly valve that can suppress the generation of unbalance torque when the valve body is in the fully open position.
[0017]
[Means for Solving the Problems]
In order to solve the above problems, a butterfly valve according to the present invention includes a housing in which a fluid flow path is formed, a valve rod rotatably attached to the housing, and a valve stem at a position that is eccentric from the rotation axis of the valve stem. And a plate-like valve body which is disposed on the flow path and is rotated by the rotation of the valve stem to open and close the flow path, and is mounted in the radial direction of the valve stem outside the housing, and the ball is the rotation axis of the valve stem A ball plunger that is displaced toward and away from the ball and a lock hole that can be engaged with the ball are formed and fixed to the valve stem, and the valve body is fully opened through the valve stem by the engagement of the ball and the lock hole. possess a locking portion for holding a predetermined open and closed positions, including a fully open position of the valve body, inclined at a predetermined angle relative to the axis of the fluid flow direction upstream portion the flow path in the valve body, the valve body Negative pressure generated upstream and downstream of the valve Wherein the the force for displacing the valve body is a position balanced.
[0018]
According to such an invention, since the valve body is held at the fully open position where the valve body holding force can be reduced by suppressing the unbalance torque, the mechanism for holding the valve body can be made compact. This can be accommodated within the face-to-face dimension of the valve, and this makes it possible to apply a sufficient locking force to the locking portion without increasing the size of the device.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. Here, in the accompanying drawings, the same reference numerals are given to the same members, and duplicate descriptions are omitted. The embodiment of the invention is a particularly useful embodiment in which the present invention is implemented, and the present invention is not limited to the embodiment.
[0022]
1 is a plan view showing a butterfly valve according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line II-II of the butterfly valve in FIG. 1, and FIG. 3 is a top view of the butterfly valve in FIG. FIG. 4 is an explanatory view showing the state of occurrence of unbalance torque when the valve element is installed in parallel with the axis of the flow path in the eccentric valve type butterfly valve in which the valve stem is divided, and FIG. FIG. 6 is an explanatory view showing the state of occurrence of unbalance torque when the valve element is installed in parallel with the axis of the flow path in the eccentric valve type butterfly valve, and FIG. 6 is an eccentric valve type butterfly valve in which the valve stem is divided FIG. 7 is an explanatory view showing a state of occurrence of unbalance torque when the valve body is installed at an inclination of 6 ° with respect to the axis of the flow path in FIG. 7, and FIG. 7 shows a valve in an eccentric valve type butterfly valve in which the valve stem is not divided. Body through the flow path FIG. 8 is an explanatory view showing a state of generation of unbalance torque when installed at an angle of 6 ° with respect to the shaft center. FIG. 8 shows an eccentric valve type butterfly valve in which a valve stem is divided. FIG. 9 is an explanatory diagram showing the state of occurrence of unbalance torque when installed with an inclination of 10 °, and FIG. 9 shows an eccentric valve type butterfly valve in which the valve stem is not divided with respect to the axis of the flow path. FIG. 10 is an explanatory view showing a state of occurrence of unbalance torque when installed at an inclination of 10 °, and FIG. 10 is a flow rate of fluid and unbalance torque using the inclination angle of the valve body with respect to the flow axis of the valve in an eccentric valve type butterfly valve as parameters It is a graph which shows the relationship.
[0023]
As shown in FIGS. 1 and 2, the butterfly valve 10 of the present embodiment has a housing 12 in which a fluid flow path 11 is formed. A valve rod 13 is rotatably attached to the housing 12 by being supported by a gland 17 and a split ring 18.
[0024]
A disc-like valve element 14 disposed on the flow path 11 is supported on the valve stem 13. The valve body 14 is rotated by the rotation of the valve rod 13 to open and close the flow path 11. In the housing 12, an annular seat ring 15 in which the outer peripheral surface of the valve body 14 that closes the flow path 11 is in close contact is prevented from being detached by the seat retainer 16 via a bolt 16 a, along the inner periphery of the flow path 11. It is attached. Further, a plurality of O-rings (not shown) are fitted between the housing 12 and the valve stem 13 to prevent fluid leakage from the valve stem 13.
[0025]
Here, in order to ensure the close contact of the valve body 14 with respect to the seat ring 15, the valve body 14 is eccentric from the rotating shaft of the valve stem 13 and is supported by the valve stem 13. Further, the valve rod 13 is divided into two parts, and the respective end portions are fixed at the end portions of the valve body 14 and are arranged coaxially apart from each other. The valve stem 13 may be one that is not divided. Further, when the valve body 14 is mounted eccentrically from the rotational axis of the valve stem 13, primary eccentricity (eccentricity between the rotational axis of the valve stem 13 and the center of the valve body 14), secondary eccentricity (in addition to primary eccentricity) , Eccentricity between the rotation axis of the valve stem 13 and the center of the seat ring 15) or tertiary eccentricity (in addition to the secondary eccentricity, the eccentricity of the axial center of the valve body 14 and the axial center of the flow path 11). Also good.
[0026]
Outside the housing 12, two prismatic ribs 12 a extend along the protruding direction of the valve rod 13 to the housing 12 so as to be opposed to each other in the direction orthogonal to the flow path 11 across the valve rod 13. It is installed. One ball plunger 19 is attached to each of the ribs 12a so that the ball is displaced in a direction in which the ball approaches and separates from the rotation axis of the valve rod 13. Further, a locking portion 20 formed with a lock hole 20 a that can be engaged with the ball of the ball plunger 19 is fixed to the valve rod 13. When the ball plunger 19 is used, a through hole is required at its installation position. However, since the rib structure as described above only needs to ensure the thickness of the plunger, the length of the through hole is also necessary. Since it can be kept to a minimum and can be easily constructed, the ball plunger 19 is easily assembled.
[0027]
As shown in FIG. 3, the locking portion 20 is substantially L-shaped, and the above-described lock holes 20a are formed at the two front end surfaces. By engaging the hole 20a with the ball, the valve element 14 supported by the valve rod 13 is held at a predetermined opening / closing position (in the present embodiment, the fully closed position and the fully open position).
[0028]
And according to such a butterfly valve 10, since it arrange | positions so that the ball | bowl of the ball plunger 19 may be displaced in the direction which approaches / separates with respect to the rotating shaft of the valve rod 13, the butterfly valve 10 is enlarged. However, the ball plunger 19 can be installed at a position away from the valve rod 13, and the valve body 14 can be held with sufficient force via the locking portion 20. This holding force is generated by a torque produced by the product of [the locking force of the ball plunger 19] and [the locking position of the ball plunger 19 from the rotating shaft of the valve stem 13, that is, the length L of the locking portion 20].
[0029]
In the case shown in the figure, the locking portion 20 is formed with two lock holes 20a, and two ball plungers 19 are attached corresponding to each lock hole 20a. One or a plurality of 19 can be provided, and it is not necessary that both are the same number. That is, depending on how the opening / closing position of the valve body 14 including the intermediate opening is set, the number of the ball plungers 19 and the lock holes 20a and the positions of these can be determined freely. It is not restricted by the form. Therefore, the ball plunger 19 may be attached in the radial direction of the valve stem 13.
[0030]
Further, in the present embodiment, the ball plunger 19 is attached to the rib 12a extending to the housing 12 and the lock hole 20a is formed in the locking portion 20, but the ball plunger 19 is connected to the locking portion 20. It is attached and the lock hole 20a may be formed in the housing 12. Furthermore, the rib 12a is not limited to a prismatic shape, and may be a columnar shape having a circular arc cross section.
[0031]
As described above, in the case of the eccentric valve type butterfly valve 10, the angle of inclination of the valve element 14 with respect to the axis center of the flow path 11 is 0 ° or more, 90 °, except when the opening is fully closed. If it is less than this, an unbalance torque acts on the valve body 14.
[0032]
The unbalance torque is due to negative pressure generated on the downstream side of the valve stem 13. Therefore, as shown in FIG. 4, when the valve stem 13 is divided, the amount of protrusion of the valve stem 13 in the flow path 11 becomes small, and the generated unbalance torque is small. On the other hand, as shown in FIG. 5, when the valve stem 13 is not divided, the valve stem 13 penetrates in the radial direction of the flow path 11, so that a large unbalance torque is generated. Become.
[0033]
Thus, if the inclination angle of the valve body 14 with respect to the fluid flow direction is the same, the unbalance torque is reduced when the valve stem 13 is divided, but the unbalance torque is suppressed to a negligible level. It is not possible. Therefore, the present inventor considered the relationship between the inclination angle of the valve body 14 and the unbalance torque. The thickness of the valve element 14 of the butterfly valve 10 to be considered is 8 mm, the diameter of the valve element 14 is 100 mm, the diameter of the valve stem 13 is 16 mm, and the eccentric amount of the valve element 14 with respect to the rotation axis of the valve stem 13 is The protrusion amount to the flow path 11 in the split type valve stem 13 is 30 mm.
[0034]
When the valve stem 13 is divided with respect to a state in which the unbalanced torque is generated when the valve body 14 is further rotated from the normal fully opened state and is inclined by 6 ° with respect to the axis of the flow path 11. FIG. 6 shows a case where the valve stem 13 is not divided.
[0035]
As shown in FIG. 6, when the valve stem 13 is divided, the force in the direction that cancels out the force in the direction of displacing the valve body 14 generated in the downstream portion is upstream of the fluid circulation direction in the valve body 14. Since the negative pressure is generated and the pressure balance of the valve body 14 is maintained, the generation of unbalance torque is suppressed.
[0036]
Further, as shown in FIG. 7, when the valve body 14 is not divided, the force in the direction of displacing the valve body 14 generated in the downstream portion is canceled in the upstream portion of the valve body 14 in the fluid flow direction. Although a force is generated, it is not large until the pressure balance of the valve body 14 is achieved.
[0037]
Next, FIG. 8 shows a case where the valve stem 13 is divided with respect to the generation state of the unbalance torque when the valve body 14 is installed with an inclination of 10 ° with respect to the axis of the flow path 11. FIG. 9 shows a case where is not divided.
[0038]
As shown in FIG. 8, when the valve stem 13 is divided, the force generated in the upstream portion in the fluid flow direction in the valve body 14 is larger than the force generated in the downstream portion, and the pressure of the valve body 14 is increased. The balance is broken in the opposite direction to that shown in FIG.
[0039]
Further, as shown in FIG. 9, when the valve body 14 is not divided, the force generated in the upstream portion in the fluid flow direction of the valve body 14 is still the force generated in the downstream portion as in the case shown in FIG. Is not big enough to counteract. As a result of further consideration by the inventor about the case where the valve element 14 is not divided, the unbalance torque is generated when the valve element 14 is installed with an inclination of 16 ° with respect to the axis of the flow path 11. Was suppressed to the maximum.
[0040]
From the above, regarding the butterfly valve 10 of the type in which the valve stem 13 is divided, the inclination angle of the valve body 14 toward the axial center of the flow path 11 is 0 °, 2 °, 4 °, 6 °, 8 °, Fluid flow rate and unbalance when set to 10 ° and when the inclination angle of the valve body 14 to the axial center side of the flow path 11 of the butterfly valve 10 in which the valve stem 13 is not divided is set to 0 ° The relationship with the torque is shown in FIG.
[0041]
From FIG. 10, when the valve stem 13 is divided, the pressure balance of the valve body 14 is maintained when the valve body 14 is installed with an inclination of 6 ° with respect to the axis of the flow path 11. Therefore, it can be seen that if this position is set to the fully open position of the valve body 14, the occurrence of unbalance torque can be suppressed.
[0042]
If the ball plunger 19 and the lock hole 20a of the locking portion 20 are engaged in this fully open position, the unbalance torque is small even if the flow rate is increased, so the ball plunger 19 is unlocked. Therefore, the phenomenon that the valve body 14 is fully closed does not occur. Therefore, as shown in FIG. 3, the angle formed by the locking portion 20 between the fully open position and the fully closed position of the valve body 14 is not 90 ° but 84 ° narrowed by 6 °.
[0043]
However, in the present embodiment, in the butterfly valve 10 in which the split type valve rod 13 is used, the fully open position of the valve element 14 is inclined by 6 ° with respect to the axis of the flow path 11 under the dimensional conditions described above. The unbalance torque is most suppressed at the position. However, if the dimensional condition changes, the inclination angle of the valve body 14 where the unbalance torque is most suppressed changes. Therefore, the present invention is not limited to the inclination angle of 6 °, and the fully open position of the valve body 14 is a position where the upstream portion in the fluid flow direction of the valve body 14 is inclined at a predetermined angle with respect to the axis of the flow path 11. It only has to be.
[0044]
Further, the fully open position of the valve element 14 may be simply set at a position inclined by 6 ° with respect to the axis of the flow path 11 without applying the above-described lock mechanism.
[0045]
Further, for the butterfly valve 10 of the type in which the valve stem 13 is not divided, the fully open position of the valve body 14 is a position where the upstream portion in the fluid flow direction of the valve body 14 is inclined at a predetermined angle with respect to the axis of the flow path 11. It only has to be. In this case, since the unbalance torque is suppressed when the inclination angle becomes larger than the divided type of the valve stem 13, it is necessary to consider that the fluid flow resistance by the valve element 14 is increased. Don't be.
[0046]
【The invention's effect】
As is apparent from the above description, the present invention can provide the following effects.
In other words, since the valve element is held in the fully open position where the valve element holding force can be reduced by suppressing the unbalance torque, the mechanism for holding the valve element can be made compact and this It becomes possible to fit within the dimensions, and this makes it possible to apply a sufficient locking force to the locking portion without increasing the size of the device.
[Brief description of the drawings]
FIG. 1 is a plan view showing a butterfly valve according to an embodiment of the present invention.
2 is a cross-sectional view taken along line II-II of the butterfly valve of FIG.
FIG. 3 is a top view of the butterfly valve of FIG. 1;
FIG. 4 is an explanatory view showing a state in which an unbalance torque is generated in a case where a valve element is installed in parallel with the axis of a flow path in an eccentric valve type butterfly valve in which a valve stem is divided.
FIG. 5 is an explanatory diagram showing an unbalance torque generation state in a case where a valve element is installed in parallel with the axis of a flow path in an eccentric valve type butterfly valve in which a valve stem is not divided.
FIG. 6 is an explanatory diagram showing an unbalanced torque generation state in a case where a valve element is installed at an angle of 6 ° with respect to the axis of a flow path in an eccentric valve type butterfly valve with a divided valve stem.
FIG. 7 is an explanatory diagram showing an unbalance torque generation state when an eccentric valve type butterfly valve in which a valve stem is not divided is installed with a valve element inclined at 6 ° with respect to the axis of a flow path; .
FIG. 8 is an explanatory diagram showing a state of occurrence of unbalance torque when the valve element is installed at an angle of 10 ° with respect to the axis of the flow path in the eccentric valve type butterfly valve in which the valve stem is divided.
FIG. 9 is an explanatory diagram showing an unbalance torque generation state when an eccentric valve type butterfly valve in which a valve stem is not divided is installed with a valve element tilted by 10 ° with respect to the axial center of a flow path; .
FIG. 10 is a graph showing a relationship between a fluid flow rate and an unbalance torque using a tilt angle with respect to a flow axis of a valve body as a parameter in an eccentric valve type butterfly valve.
FIG. 11 is a cross-sectional view showing a lock mechanism in a conventional butterfly valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Butterfly valve 11 Flow path 12 Housing 13 Valve rod 14 Valve body 15 Seat ring 16 Seat retainer 17 Gland 18 Split ring 19 Ball plunger 20 Locking part 20a Lock hole 112 Housing 113 Valve rod 114 Valve body 119 Ball plunger 120 Locking part 120a Lock hole 121 Flange

Claims (3)

A housing in which a fluid flow path is formed;
A valve stem rotatably mounted on the housing;
A plate-like valve element that is supported by the valve stem at a position eccentric from the rotation axis of the valve stem and disposed on the flow path, and that rotates by the rotation of the valve stem to open and close the flow path;
A ball plunger attached to the outside of the housing in the radial direction of the valve stem and displaced in a direction in which the ball approaches and separates from the rotation axis of the valve stem;
A lock hole that can be engaged with the ball is formed and fixed to the valve stem, and the valve body is held in a predetermined opening / closing position including the fully opened state through the valve stem by the engagement of the ball and the lock hole. possess a locking unit that,
The fully open position of the valve body is such that the upstream portion in the fluid flow direction in the valve body is inclined at a predetermined angle with respect to the axial center of the flow path, and the negative pressure generated in the upstream portion of the valve body and the downstream portion of the valve body A butterfly valve characterized by being in a position balanced with the force generated in the direction of displacing the valve body . 2. The butterfly valve according to claim 1, wherein the valve stem is divided into two parts, and the respective end portions are fixed at the end portions of the valve body and are spaced apart from each other on the same axis. The fully open position of the valve body is such that the upstream portion in the fluid flow direction of the valve body is inclined with respect to the axis of the flow path, and the angle formed by the plane of the valve body and the axis of the flow path is 6 ° The butterfly valve according to claim 2, wherein

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