JP3648468B2 - Eccentric butterfly valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an eccentric butterfly valve that prevents wear and damage to a primary body and a valve body of a valve and improves the flow rate under specified conditions of a high-pressure fluid.
[0002]
[Prior art]
An annular seat ring made of an elastic material is provided between an inner peripheral surface of one end portion of a hollow cylindrical main body made of a rigid material and a peripheral portion of a valve body made of a rigid material rotatably supported in the main body. An eccentric butterfly valve in which the rotation center axis of the valve stem and the sealing surface where the valve body peripheral surface and the main body are pressed against each other via the annular seat ring do not coincide with each other is connected to the annular seat ring when the valve is closed The present applicant has previously developed a sheet portion having a mountain-shaped cross section for press contact with the peripheral portion along the circumferential direction (see Japanese Utility Model Publication No. 62-44215).
[0003]
As shown in FIG. 12, a valve rod (valve shaft) 2a is rotatably supported on an annular valve body 1a, and a valve body (valve plate) is supported on the valve rod 2a. 3a is eccentrically fixed, and at the valve closing position shown in the figure, the periphery of the valve body is pressed against a seat ring 4a attached to the inside of the valve body, and thus the outer surface has a mountain-shaped cross section. Is shut off. When this is arranged in the pipeline, it is tightly attached to the left (opposite side) flange (not shown) and the bolt (not shown) by the right pipe flange F shown by the two-dot chain line. The pipe inner peripheral face Fa fixed to the flange F illustrated by the two-dot chain line is parallel to the flow direction axis as is well known, and when the valve is slightly open, the orifice side (the butterfly valve body is counterclockwise) The fluid flow path at the tip end side in the rotation direction) is such that the inner peripheral surface of the main body and the portion of the projecting seat ring (corresponding to the orifice side flow path) are under high pressure and high flow rate fluid conditions. In some cases, it was worn out and damaged.
[0004]
In addition, including the above-mentioned known examples, at a minute opening, the flow rate is remarkably small with respect to the valve opening, making it difficult to use near the minute opening.
[0005]
When the opening is very small, this is particularly noticeable in the orifice-side flow path, particularly near the valve axis orthogonal position. That is, the passage of fluid at a minute opening is because the valve shaft orthogonal position is larger than the valve shaft direction position. Accordingly, the inner peripheral surface of the valve body and the outer peripheral surface (edge) of the valve body near the valve axis orthogonal position may be worn, worn or damaged by the fluid. This is particularly noticeable when impurities, foreign matter, solids, etc. are mixed in the fluid.
[0006]
In addition, at a small opening, the fluid generates a suction force in the inner diameter direction on the back side (outflow side) of the valve body together with a high flow rate, and the seat ring made of an elastic material may contract in the inner diameter direction. Is remarkable. (The reason for this is that the position in the valve shaft direction prevents the valve body boss from shrinking in the inner diameter direction.) From these, seizure (integrated vulcanization) is performed to prevent the seat ring from dropping (shrinking) from the main body. ) And so on.
[0007]
Also, even at a very small opening, that is, near 30 ° opening, only 10% of the total flow coefficient flows inside and outside, and the flow rate ratio is remarkably small with respect to the total opening 90 ° of the butterfly valve (1/3 is opened). In spite of this, the flow rate means 10% inside or outside) Some users did not fully understand the flow rate characteristics of the butterfly valve, causing trouble. There was a tendency that control at a minute opening was made more difficult than these.
[0008]
Also, at a very small opening, a suction force is generated in the inner diameter direction on the back side of the valve body, that is, the part is in a vacuum state, and the valve body also acts to move in the valve closing direction. As a result, the valve cannot be opened unless an actuator that requires excessive torque is selected. That is, a torque that overcomes the unbalance torque (unbalance torque) is required.
[0009]
[Problems to be solved by the invention]
As described above, in the prior art, as shown in FIG. 11, when the valve body 3 is slightly opened in the counterclockwise direction, the gap C between the inner surface of the flow path of the body 1 on the orifice side and the distal end portion of the valve body 3. ₁ Since the fluid is narrow and the fluid flows rapidly to the secondary side from this narrow gap (jet), the inner peripheral surface of the body and the outer peripheral surface (edge) of the valve body may be worn or damaged. In addition, the ratio of the valve opening to the flow rate is extremely small at the minute opening, and control at the minute opening is difficult.
[0010]
Also, unbalanced torque at minute opening (torque generated by the differential pressure across the valve due to running water during valve opening and closing, does not work in the fully open / closed position of the valve, becomes large at intermediate opening, The actuator corresponding to this is large, which causes a cost increase.
[0011]
The present invention prevents damage to the inner peripheral surface of the valve body and the outer peripheral surface (edge) of the valve body in the orifice-side flow path at the minute opening, and improves (increases) the flow rate at the minute opening. In addition, the technical problem is to reduce the unbalance torque value at the time of a very small opening and to reduce the cost by saving labor and downsizing the corresponding actuator.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the means of the present invention includes an inner peripheral surface of one end of a hollow cylindrical main body made of a rigid material and a valve made of a rigid material rotatably supported in the main body. An annular seat ring made of an elastic material is interposed between the peripheral edge of the body, and the rotation center axis of the valve stem does not match the seal surface where the valve body peripheral surface and the main body are in pressure contact with each other via the annular seat ring In the eccentric butterfly valve, the annular seat ring is continuously formed with a chevron-shaped cross section for pressure contact with the peripheral edge of the valve body when the valve is closed, and faces at least the primary side of the main body. Forming an inclined surface between the outer peripheral side surface and the inner peripheral surface, the angle formed by the inclined surface and the outer peripheral side surface and the width of the inclined surface being the largest at the valve shaft orthogonal position, the smallest at the valve shaft position, and Opposes at least the primary side of the disc Cutout part of Karadagaishu the rear side, the notch width from the valve body outer periphery, the greatest in the valve shaft perpendicular position, is characterized in that the minimum at the valve stem position near.
[0013]
In addition, a valve is formed on both side surfaces of the main body, the angle and width of both slopes are maximized at the valve shaft orthogonal position, minimized at the valve shaft position, and opposed to the primary and secondary sides of the valve body. The width of the notch from the outer periphery of the body is the largest at the valve shaft orthogonal position and the smallest at the vicinity of the valve shaft position.
[0014]
In addition, the continuation from the valve shaft orthogonal position where the width of the slope and the notch is the largest to the vicinity of the valve shaft position where the width is the smallest is continuous with a curve.
[0015]
Further, the continuation from the valve shaft orthogonal position where the width of the slope and the notch is the largest to the vicinity of the valve shaft position where the width is the smallest is continued at the stepped portion.
[0016]
Further, the continuity from the valve shaft orthogonal position where the width of the slope and the notch is the largest to the vicinity of the valve shaft position where the width is the smallest is continuous with a straight line.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention will be described below. The present invention provides an inclined butterfly valve having an inclined surface formed between an outer peripheral side surface and an inner peripheral surface opposed to the primary side at least, and an angle between the inclined surface and the outer peripheral surface and the width of the inclined surface. The largest in the axis orthogonal position, the smallest in the valve axis position, and the width of the notch from the outer periphery of the valve body facing the at least primary side of the valve body to the back side is maximized in the valve axis orthogonal position, Smallest in the vicinity of the valve shaft position.
[0018]
Between the maximum position and the minimum position of the valve body slope, any structure such as a curved line, a straight line, or a stepped structure may be used.
[0019]
In addition, the inclined surface needs to be formed on at least the surface facing the primary side of the valve, but can be formed on both sides depending on the fluid flow direction, specification conditions, and the like.
[0020]
Next, the maximum width of the valve body notch is the valve shaft orthogonal position, the minimum width in the vicinity of the valve shaft position, and between the maximum width and the minimum width can be any curve, straight line or stepped continuous It is good also as a structure.
[0021]
The combination of the valve body and the valve body is free. In addition, the seat ring fixing method may be other than this figure.
[0022]
Furthermore, any structure having a flange connection on both sides of the main body or a flangeless type may be used, and the structure of the main body is not particularly limited. Further, the material of the main body and valve body may be any of cast iron, ductile cast iron, cast steel, stainless steel, etc., which are generally rigid materials. Further, the material of the seat ring may be a simple substance or a composite such as an elastic synthetic rubber or synthetic resin.
[0023]
Since the main body of the present invention and the valve shaft orthogonal position of the valve body have the largest width of the slope and the width of the notch, the part of the main body and the valve body is worn in the orifice-side flow path at the time of a slight opening, The flow rate can be increased without being damaged, the unbalance torque can be suppressed, and a long-life butterfly valve can be provided.
[0024]
【Example】
A preferred embodiment of the present invention will be described with reference to FIGS.
Reference numeral 1 denotes a body of an eccentric butterfly valve, which is made of a rigid material such as metal or hard synthetic resin, and has a hollow cylindrical fluid passage 2 penetrating therein. In the fluid passage 2, as shown in FIG. 1, which is a cross-sectional view in the valve shaft (rod) direction, one side of the valve body support 3b fixed to the valve shaft (rod) 7 via a taper bolt 8 is provided. Eccentric (left side in FIG. 1), and the valve body 3 is pivotally supported by the valve shaft 7 and is elastic rubber or synthetic resin at a position contacting the peripheral surface of the valve body 3 in the fully closed position. After the seat ring 4 having a chevron-shaped seat portion 5 (FIG. 3) protruding in the inner diameter direction is fitted into the groove portion of the valve body 1, epoxy resin is injected into the back side of the seat ring 4 from the outside not shown. It adheres and prevents the main body 1 from falling off.
[0025]
The main body (valve main body) 1 is formed between the inner peripheral surface 9 and the outer peripheral side surface 10 of the main body 1 at a position orthogonal to the valve shaft (rod) 7 penetrating in the diameter direction, as shown in FIG. The width L ₂ and the angle θ _{2 of the} slope 11 are formed to be the largest, and as shown in FIG. 3, the width L ₁ and the angle θ ₁ gradually decrease and become smaller as approaching the valve shaft (rod) position. ing.
[0026]
The inclined surface 11 is formed on the primary side (inflow side) of the main body 1, but can also be formed on both side surfaces of the main body 1, that is, the primary side and the secondary side (outflow side).
[0027]
Next, FIG. 7 shows a front view seen from the secondary side (outflow side) of the valve body 3, and the valve shaft 7 is pivotally supported in the Y-Y 'axis direction. In FIG. 9, the hatched portion is indicated by a width M of a notch to the back surface of the outer peripheral portion, the valve axis orthogonal position is EE ′, and the cross section of the portion is shown in FIG. In the figure, M ₂ is the largest in the width of the notch to the back, and T is the thickness of the outer periphery of the valve body, which is the minimum thickness that contacts and separates from the seat ring 4 when the valve is closed. Further, FIG. 8 is the smallest indicates notch width M ₁ to the rear in the vicinity of the valve shaft position. In FIG. 7, the left side in the YY ′ valve axis direction shows a continuous pattern from the valve axis orthogonal position (EE ′) to the vicinity of the valve axis position (DD ′) with a curved line, and YY The right side of the valve axis direction shows a pattern in which the continuation is continued by the step portion.
[0028]
FIG. 5 shows a development view of the 90 ° range of the valve axis orthogonal position of the main body 1, where 0 ° indicates the valve axis position and 90 ° indicates the valve axis orthogonal position.
In the figure, the hatched portion indicates the width of the slope, the maximum width being L ₂ , the minimum width being L _1, and a continuous pattern of these curves 12.
The maximum width L ₂ is preferably 60 ° inside or outside in total 30 ° on both the upper and lower sides in the circumferential direction from the valve axis orthogonal position. The range of the valve is not limited to this range.
[0029]
Further, FIG. 6 shows a pattern in which the maximum width and the minimum width are continuously connected by a straight line 13 in the same manner. Although not shown, the maximum width and the minimum width can be continued by providing a stepped portion.
[0030]
FIG. 11 is a sectional view showing the main part of the valve body orthogonally positioned at the small opening orifice side, the valve shaft orthogonal position of the conventional example shown for comparison with FIG. 10 of the present invention, and the primary side of the main body 1. The inner peripheral surface 9 is a cylindrical surface and is not provided with a slope, and the valve body 3 is not provided with a notch on the back surface, and the orifice-side flow path at a minute opening degree at a position orthogonal to the valve axis. It shows a narrow stream over a gap C ₁ of.
[0031]
On the other hand, FIG. 10 is an enlarged cross-sectional view of the main parts of the main body 1 and the valve body 3 at the position of the small opening orifice side valve axis orthogonal to the present invention. The flow gap C ₂ formed with the notch top is much larger than the flow gap C _{1 in} FIG. 11 (conventional example). By comparing the flow gaps C ₁ and C _{2 of} these two, the present invention is compared with the conventional example (solid line) at a minute opening in the flow characteristic curve shown in FIG. (Dotted line) shows that the improvement (increase) in the flow rate is remarkably achieved.
[0032]
【The invention's effect】
As described above, according to the present invention, in the eccentric butterfly valve, the annular seat ring is continuously formed along the circumferential direction with a chevron-shaped seat portion for pressure contact with the valve body peripheral portion when the valve is closed. And forming an inclined surface between the outer peripheral side surface facing the at least primary side of the main body and the inner peripheral surface, the angle formed by the inclined surface and the outer peripheral side surface and the width of the inclined surface being maximized at the valve axis orthogonal position, A part of the outer periphery of the valve body that is the smallest at the axial position and that faces at least the primary side of the valve body is notched to the back side, and the width of the notch from the outer periphery of the valve body is the largest at the position orthogonal to the valve axis However, by making it the smallest in the vicinity of the valve shaft position, the following effects can be obtained.
[0033]
(I) Abrasion and damage to the inner peripheral surface of the main body and the outer peripheral surface (edge) of the valve body due to a rapid fluid flow on the orifice side at the minute opening degree when the valve is closed or opened can be significantly prevented.
[0034]
(Ii) The flow rate can be significantly improved (increased) when the opening is very small.
[0035]
(Iii) The unbalance torque value can be reduced by improving (increasing) the flow rate at a minute opening, and the cost can be significantly reduced by labor saving and downsizing of the actuator.
[0036]
(Iv) When the opening is very small, the back of the orifice side valve element is improved in the inner diameter direction (vacuum state), and the protrusion and damage of the seat ring can be prevented.
[Brief description of the drawings]
FIG. 1 is a sectional view of a position of an eccentric butterfly valve according to the present invention in a valve axial direction.
FIG. 2 is a sectional view of the eccentric butterfly valve according to the present invention at a position perpendicular to the valve axis.
FIG. 3 is an enlarged view of a cross section in the valve axis direction of the main body of the present invention.
FIG. 4 is an enlarged view of a cross section at a position orthogonal to the valve axis of the main body of the present invention.
FIG. 5 is a development view of the main body according to the present invention (90 ° range of the inner peripheral surface).
FIG. 6 is a development view of a modification of the main body according to the present invention.
FIG. 7 is a front view of the valve body according to the present invention viewed from the secondary side (outflow side).
FIG. 8 is an enlarged view of an outer circumferential notch in the vicinity of the valve shaft position of the valve body of the present invention.
FIG. 9 is an enlarged view of an outer circumferential notch at a position perpendicular to the valve axis of the valve body of the present invention.
FIG. 10 is an enlarged view of the main body and the valve body at the position of the small opening orifice, the valve shaft orthogonal position according to the present invention.
FIG. 11 is a similar enlarged view of a conventional example.
FIG. 12 is an enlarged view of a main part showing an example of a conventional valve.
FIG. 13 is a flow characteristic graph showing a comparison between a conventional valve and the present invention.
[Explanation of symbols]
1 Body (Valve body)
2 Fluid passage 3 Valve body 4 Seat ring 5 Angle seat 6 Shaft seal packing 7 Valve shaft (valve stem)
8 Tapered bolt 9 Inner peripheral surface 10 Outer peripheral surface 11 Slope 12 Curve 13 Straight line C Overflow gap (orifice side flow path)
L Width of slope θ Angle of slope M Width of notch T Thickness of outer periphery of valve body

Claims (5)

An annular seat ring made of an elastic material is provided between an inner peripheral surface of one end portion of a hollow cylindrical main body made of a rigid material and a peripheral portion of a valve body made of a rigid material rotatably supported in the main body. An eccentric butterfly valve in which the rotation center axis of the valve stem and the seal surface where the valve body circumferential surface and the main body are pressed against each other via the annular seat ring do not coincide with each other is connected to the annular seat ring when the valve is closed A sheet portion having a mountain-shaped cross section for pressure contact with the peripheral edge portion is continuously formed along the circumferential direction, and a slope is formed between the outer peripheral side surface and the inner peripheral surface facing at least the primary side of the main body, The angle between the inclined surface and the outer peripheral side surface and the width of the inclined surface are maximized at the valve shaft orthogonal position, minimized at the valve shaft position, and a part of the outer periphery of the valve element facing at least the primary side of the valve element Cut out from the outer periphery of the valve disc The Kino width, the greatest in the valve shaft perpendicular position, eccentric butterfly valve, characterized in that the minimum at the valve stem position near. Slope is formed on both sides of the main body, the angle and width of both slopes are maximized at the valve shaft orthogonal position, minimized at the valve shaft position, and the valve body outer periphery facing the primary and secondary sides of the valve body The eccentric butterfly valve according to claim 1, wherein the width of the notch from the valve is maximized at a position orthogonal to the valve axis and minimized at the vicinity of the valve axis position. The eccentric butterfly valve according to claim 1 or 2, wherein the continuation from the valve shaft orthogonal position where the width of the slope and the notch is the largest to the vicinity of the valve shaft position where the width is the smallest is continuous with a curve. 3. The eccentric butterfly valve according to claim 1, wherein the continuation from the valve shaft orthogonal position where the width of the slope and the notch is the largest to the vicinity of the valve shaft position where the width is the smallest is continued at the stepped portion. The eccentric butterfly valve according to claim 1 or 2, wherein the continuation from the valve shaft orthogonal position where the width of the slope and the notch is the largest to the vicinity of the valve shaft position where the width is the smallest is a straight line.

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