JP2001012620A - Butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use stably over a long term by forming the outer periphery edge of a valve element and seat ring in a truncated cone shape and off-centering its top from the center line of the longitudinal direction of the valve main body. SOLUTION: A seat ring 5, press-contacted to the outer periphery surface of a valve element 3, for closing a valve is fixed to the inner periphery surface of a valve main body 1. The inner periphery surface of the set ring 5 is formed in an oval shape following to the oval shape of the outer periphery surface of the valve element 3 so as to guarantee the adhesiveness to the valve body 3. As the seat ring 5 is constituted by a triple eccentricity such as a primary eccentricity for separating the seat surface formed on the outer periphery surface of the valve element 3 and the seat ring 5 installed on the valve main body 1 from the center of the valve element 3 and the center of a valve rod, while being fixed to the valve main body 1 by a seat press member 7, a secondary eccentricity for separating from the center of the valve main body 1 and a tertiary eccentricity for slanting against the center line of the valve main body 1, while positioning the top of truncated cone shape for constituting the valve main body 1 and the seal surface of the valve element 3 to the opposite side of the valve rod 4, a stable function can be held for a long term.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentric butterfly valve which opens and closes and controls a high-temperature and high-pressure fluid flowing through a pipe, and more particularly to a triple eccentric butterfly valve which can be used stably for a long period of time.

[0002]

2. Description of the Related Art Conventionally, a triple eccentric butterfly valve in which one of a valve body and a sealing portion of a seat ring is inclined with respect to the other in a direction perpendicular to a valve stem is known, for example, Japanese Patent Publication No. 47-16895. Japanese Patent Publication No. 3-10828, Japanese Utility Model Publication No. 57-59258, and the like. In these known triple eccentric butterfly valves, a valve seat such as an elastomer is fixed to the outer peripheral edge of the valve body by bolting with a member such as a mounting plate. And the flow velocity in the valve element portion increases. For this reason, vibration is generated in the vicinity of the mounting member and the bolts, and there is a risk that the mounting portion may be loosened or dropped. Also, when the valve is fully opened, the upstream outer peripheral edge of the valve body is worn or damaged by impurities, foreign matters, hard sand, or the like contained in the fluid, and when the valve is fully closed, the valve body is attached to the main body side valve seat. Since it is not reliably pressed, it causes fluid leakage.

[0003]

According to the present invention, the valve seat is fixed to the valve body side instead of the outer peripheral portion of the valve body.
It is possible to reduce the cross-sectional shape, especially the thickness, of the valve body, reduce the pressure loss when the valve is fully opened, suppress the generation of vibration, reduce the abrasion and damage by impurities and foreign substances in the fluid, and reduce the fluid leakage. The objective is to eliminate the cause.

[0004]

In order to solve the above-mentioned problems, the present invention adopts a valve body having a substantially cylindrical fluid passage penetrating therethrough, and the valve body being rotatable via a valve rod. The valve ring consists of a disc-shaped valve body made of a rigid material that is pivotally supported, and the valve ring is eccentrically supported with respect to the center of the valve body. Temporarily tightened, when the pipe is connected, the main fastening, welding a separate sealing material to the outer peripheral edge of the valve body, forming a fish-tail-shaped overhang on the outer peripheral edge on the downstream side in the valve opening operation direction, the outer peripheral edge of the valve body and the seat The ring is formed in a truncated cone shape, and the apex of the truncated cone is eccentric from the longitudinal center line of the valve body.

[0005] The inner peripheral surface of the seat ring fixed to the valve body is formed of one of a single material, a laminated material of metal and graphite, or a composite material of elastomer and fluororesin.

[0006] A gasket is provided at the corners of the valve body and the seat holding member to prevent external leakage of fluid.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below. Referring to the drawings, (1) is a valve body, which has a substantially cylindrical fluid passage (2) penetrating therethrough, and a disc-shaped valve body (3) for opening and closing the fluid passage (2) is provided with a valve stem ( It is rotatably supported at 4). The valve body (3) is made of a rigid material such as metal having an outer peripheral surface having an elliptical shape, and the valve stem (4) is fixed by a valve stem pin (6). One end of the valve stem (4) extends out of the valve body, and a desired actuator which is driven manually, electrically, or by pressure is connected to the outer end thereof to drive and rotate the valve body (3). Can be done. Reference numeral (5) denotes a seat ring which is pressed against the outer peripheral surface of the valve body (3) to close the valve.
Is fixed on the inner peripheral surface of the. The inner peripheral surface of the seat ring (5)
It is formed in an elliptical shape following the elliptical shape of the outer peripheral surface of the valve element (3), and guarantees close contact with the valve element (3). Seat ring
(5) The seat surface formed on the outer peripheral surface of the valve body (3) and the valve body (1) are fixed to the valve body (1) by the seat pressing member (7).
Primary eccentricity of the seat ring (5) attached to the center of the valve body (3) and the center of the valve stem (4), secondary eccentricity of the valve body (1) away from the center, and the valve body (1) And a cubic eccentricity, in which the apex of the conical shape constituting the sealing surface of the valve body (3) is located on the opposite side of the valve stem (4) and is inclined with respect to the center line of the valve body (1). Make up.

The seat ring (5) is made of a metal sheet obtained by laminating a thin metal plate and graphite (graphite), and is fixed by being sandwiched between the valve body (1) and the sheet pressing member (7). Also, steps (1a) and (7a) are provided on the contact surfaces of the valve body (1) and the seat holding member (7) with the seat ring (5), respectively. Step
(5a) is engaged to prevent the seat ring (5) from coming off in the inner diameter direction. The seat ring (5) and the seat holding member (7) are provided with a plurality of mounting bolts (8) arranged at a constant pitch on a concentric circle with the outer peripheral surface of the seat ring (5).
Temporarily fixed together with the valve body (1). The inner diameter of the sheet pressing member (7) is similar to the inner diameter of the seat ring (5) and is slightly larger than that of the seat ring (5).
(7) The contact between the valve body (3) and the valve body (3) can be avoided, and by considering the inner diameter of the valve body with respect to the outer diameter of the seat ring, the seat ring can be brought into contact with the valve body (3).
The self-centering function of (5) can be obtained. The temporarily fixed mounting bolt (8) is connected to a pipe flange (9) as shown in FIG.
Thus, the flange portion is securely press-fitted, and the leakage of fluid to the outside can be prevented in combination with the gasket (10) at the corner. Also, the temporarily fastened mounting bolts (8)
Is sealed by the pipe gasket (11) at the time of piping, so there is no danger of loosening or falling off, and the number of bolts is such that the sheet pressing member does not fall off during transport, and the structure is simplified.

The inner peripheral surface of the seat ring (5) and the outer peripheral surface of the valve body (3) are both elliptical, and the outer peripheral edge of the valve body (3) and the inner peripheral edge of the seat ring (5) are The valve body is formed to have substantially the same diameter with a slightly larger valve body and a slightly smaller seat ring. Then, as shown in FIG. 6, the valve element (3) rotates counterclockwise in the figure around the axis (i) of the valve stem (5), and the axis (i) of the valve stem (5). Is located on the opposite side of the apex (a) of the conical surface formed by the outer peripheral surface of the valve body (3), is deviated from the center line (e) of the valve body (3) by the primary eccentricity (f), It is deviated from the center line (h) of the main body and the valve element by the secondary eccentricity (g). The apex (a) is located on the horizontal line (b) of the horizontal valve seat (A), the apex angle (j) is usually preferably about 20 degrees, and the inclined valve seat (B) is located on the other inclined line (d). ). The half angle of the apex angle (j) becomes the center line (c) of the cone, and the valve body (3), the valve seat, and the like are formed symmetrically with respect to the center line (c). On the other hand, the outer peripheral surface of the seat ring (5) and the inner peripheral surface of the valve main body (1) are both formed in a perfect circle, and the seat ring (5) is connected to the valve main body via the seat holding member (7).
Fixed and fixed to (1).

A matching mark for positioning is provided on the outer peripheral surface of the seat holding member (7), and a matching mark corresponding to the matching mark is formed on the seat ring (5) and the valve body (1).
To be provided respectively. Seat holding member (7), seat ring
While the outer circumference of (5) and the inner circumference of the valve body are both circular, the inner circumferences of the seat holding member (7) and the seat ring (5) are elliptical, so that the mounting bolt (8) can be mounted. Depending on the tightening state, there is a concern that the fixing position of the seat ring (5) and the sheet holding member (7) may be deviated in the circumferential direction. However, by matching the matching mark, the seat ring (5) and the sheet holding member are held. It is possible to prevent the fixing position of the member (7) from being biased in the circumferential direction. On the other hand, a valve element (3) fixed to a valve stem (4)
The elliptical shape of the outer peripheral edge of the valve body is determined in the valve axis direction, and the reliable fixation to the conical valve seat leads to an improvement in the effect of preventing leakage.

The inner peripheral surface of the seat holding member (7) for fixing the seat ring (5) is formed in a similar elliptical shape larger than the inner peripheral surface of the seat ring (5). By making the projecting length in the inner diameter direction of 5) constant over the entire circumference, the amount of pressure deformation by the valve element (3) when the valve is fully closed is constant over the entire circumference, and stable sealing performance is achieved. It is possible to obtain. In FIG. 6, the input angle (k) indicates the angle at the time of sitting from opening to closing, and is desirably set to about 15 degrees from the viewpoint of sealing performance and ease of opening and closing the valve (separation and seating). . That is, when the input angle (k) is large, the opening and closing of the valve is easy, but the sealing performance is reduced. Conversely, when the input angle (k) is small, the sealing performance is increased but the opening and closing of the valve becomes difficult. Would.

In FIG. 1, the valve stem (4) is arranged horizontally, the flow direction of the fluid is on the left side (the flat surface side of the valve body), the tilt valve seat is on the lower side, and the horizontal valve seat is on the upper side. When the body (3) is rotated counterclockwise to control seawater or the like in which foreign matter or the like in the fluid is mixed, the foreign matter is deposited at a position opposite to the rotation direction of the valve body (3). Therefore, the opening and closing properties of the valve element (3) are ensured, and troubles that may hinder the opening and closing of the valve are eliminated. Further, in this case, the force due to the fluid flow acting on the flat side of the valve element (3) theoretically acts in the direction of opening, so that the ease of opening and closing the valve and the rotational torque are improved. Conversely, when the flow is on the valve stem side, the closing force acts on the valve body, so that the sealing performance increases, but the opening / closing performance deteriorates and the rotational torque increases. Although it differs depending on the type and flow of the fluid, the rotation torque of the valve stem increases by about 40%.

As shown in FIG. 5, on the outer peripheral surface of the valve body (3), depending on the fluid specification conditions such as the type of fluid, pressure, and temperature,
Metals with excellent corrosion resistance and wear resistance, such as stainless steel,
A sealing surface (3a) made of a nickel alloy or the like is integrally formed on the outer peripheral surface of the valve body (3) by a method such as overlay welding. Valve body
If (3) has a small diameter, it may be cast and formed as one piece.
In particular, for a large diameter valve or the like, it is desirable to form a separate metal by welding as shown in FIG. As the stainless steel forming the sealing surface (3a), there are austenitic and ferritic stainless steels, and preferably SUS316L, SUSY4
30 and so on. As the nickel alloy, there are nickel-molybdenum-based, nickel-molybdenum-chromium-based and the like, and preferably, DNiMo-1, DNiCrMo-3 and the like. The sealing surface (3a) is preferably made different in material and surface hardness from the seat ring (5) to have a higher surface hardness than the seat ring (5), for example, about HB410. The seat ring (5) is made of a metal sheet obtained by laminating the metal and graphite according to the fluid specification conditions, as well as a non-metal such as stainless steel, a nickel alloy or the like, an elastomer, a fluororesin, or a metal and a non-metal. May be used.

On the outer peripheral edge of the valve body (3) on the downstream side in the valve opening direction,
As shown in FIGS. 3 and 4, fish-tail-shaped overhangs (3b) and (3c) are formed to improve the dynamic torque (unbalance torque) of the fluid, which is one of the intrinsic torques of the butterfly valve. The valve element produces a maximum torque at around the opening of about 75 °, and functions to close the valve element. Fishtail-shaped overhang on the valve stem insertion side
By making the height of (3b) less than the maximum thickness of the valve stem insertion portion, and lower than the fishtail-like overhanging portion (3c) on the opposite side,
The dynamic torque value can be reduced by a maximum of about 25 to 40% as compared with the conventional one, and a small motor or power means can be used. The cross section at the center of the valve body (3) has a shape protruding left and right like a fish tail as shown in FIG. 1 and has a flared shape along the downstream peripheral edge of the valve body. And is formed on both the front and back surfaces of the valve body. The downstream peripheral edge of the valve element is
It is formed on the tilt valve seat (3d).

[0015]

According to the present invention, the following effects can be obtained. The seat ring of the valve body can be used for a long time, and it can be easily attached and detached in case of wear, etc.
Since the seat surface made of corrosion-resistant and wear-resistant metal is integrally formed on the outer peripheral edge on the inflow side when the valve element is opened, the seat ring can be prevented from being worn or damaged by the fluid. Is temporarily tightened with bolts and then fully tightened with pipe connection flanges, so that the flanges are securely crimped, and the gasket at the corners can be used to eliminate fluid leakage to the outside. Since it is sealed by the gasket, there is no danger of loosening and falling off.The temporarily fastened bolts do not strongly press the seat ring, and the number of bolts is sufficient to prevent the sheet holding member from falling off during transport. The simplified metal is welded to the outer peripheral edge of the valve element, which is optimal for the fluid conditions, so that the valve section shape, especially the wall thickness, can be reduced within the allowable strength range, and the weight can be reduced. By forming a fish-tail-shaped overhang on the outer peripheral edge on the downstream side in the valve opening operation direction, the dynamic torque (unbalance torque) of the fluid can be reduced at a minute opening and an intermediate opening. The valve can be opened and closed and controlled with a small and inexpensive actuator. Since the sealing surfaces of the seat ring and the valve body are frusto-conical, the two surfaces are integrated in a wedge shape to exhibit a tight sealing effect. The most suitable material can be selected and formed on the sealing surface depending on the fluid conditions (fluid type, pressure, temperature, etc.) to be passed, and can be used stably for a long time.

[Brief description of the drawings]

FIG. 1 is a sectional view of an eccentric butterfly valve according to the present invention.

FIG. 2 is an enlarged sectional view of a valve body and a valve seat.

FIG. 3 is a side view of a valve body.

FIG. 4 is a plan view in which the front and back surfaces of the valve element are illustrated separately along line AA ′;

FIG. 5 is an enlarged sectional view showing a sealing surface of a valve body.

FIG. 6 is an explanatory diagram showing a relationship between a valve rod and a valve seat in a valve body.

[Explanation of symbols]

 (1) Valve body (1a) Step section (2) Fluid passage (3) Valve body (3a) Seal surface (3b) Fishtail-shaped protrusion (3c) Fishtail-shaped protrusion (3d) Inclined valve seat (4) Valve stem (5) Seat ring (5a) Step (6) Valve stem pin (7) Seat holding member (7a) Step (8) Mounting bolt (9) Piping flange (10) Gasket (11) Piping gasket

Claims (3)

[Claims] A valve body penetrating a substantially cylindrical fluid passage;
A butterfly valve, comprising a disc-shaped valve body made of a rigid material rotatably supported on the valve body via a valve rod, wherein the valve rod is eccentrically supported with respect to the center of the valve body. Temporarily fasten the seat ring to the main body detachably with a seat ring holding member, fully fasten it at the time of pipe connection, weld a separate sealing material to the outer peripheral edge of the valve body, and fish-tail up the outer peripheral edge on the downstream side in the valve opening operation direction A butterfly valve, wherein a protruding portion is formed, an outer peripheral portion of a valve body and a seat ring are formed in a truncated cone shape, and a vertex of the truncated cone is eccentric from a longitudinal center line of the valve body. 2. An inner peripheral surface of a seat ring fixed to a valve body is formed of any one of a single material, a laminated material of metal and graphite, or a composite material of elastomer and fluororesin. Item 7. The butterfly valve according to item 1, wherein 3. The butterfly valve according to claim 1, wherein gaskets are provided at corners of the valve body and the seat holding member to prevent external leakage of fluid.