JPH11264477A - Butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To concurrently provide an excellent quality of a central type butterfly valve and an eccentric type butterfly valve, and prevent shortening of a life due to high torque and wearing by usual contact in the vicinity of a valve rod through part of a valve element and a seat ring. SOLUTION: In a butterfly valve mounting an annular seat ring consisting of elastic material performing seal action in cooperation with a peripheral edge part of a valve element an main unit, the annular seat ring 12 consisting of elastic material is mounted in an internal peripheral surface of the main body 11 so as to cover the internal peripheral surface, and the valve element 14 is eccentrically mounted through an eccentric support member 14a abutted to an inner surface of the seat ring 12 through a spacer 16, in a valve rod 13 supported to be inserted in the main body 11 through the seat ring 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve having both advantages of a center type butterfly valve and an eccentric type butterfly valve.

[0002]

2. Description of the Related Art In general, a butterfly valve is provided inside a main body (valve main body) so as to rotatably support a valve body attached to a valve stem, and the valve body is rotated through the valve stem to rotate the valve body. In this structure, the center type butterfly valve and the eccentric type butterfly are used in a sealing structure between an annular seat ring made of an elastic material and an outer peripheral edge of a valve body, which is mounted on the inner surface of the main body. Valves are classified into two types.

FIG. 2 shows a typical structure of a center type butterfly valve. A longitudinal section including a center of a valve rod in a fully closed state of a wafer type (thin type) center type butterfly valve having no flange on both sides. FIG. In the figure, on the inner peripheral surface of the main body 1,
An annular seat ring 2 made of an elastic material such as rubber fits ear portions 2a integrally formed on both sides thereof into annular concave portions formed on both side surfaces of the main body 1 and engages with each other to be attached and fixed to the main body 1. Have been. A valve stem 3 is inserted into and supported by the main body 1 so as to pass through the center of the annular seat ring 2, and a valve element 5 is attached to the valve stem 3 via a connecting pin 4. In the center type butterfly valve shown above, when the valve body 5 is fully closed, the sealing surface where the outer peripheral edge of the valve body 5 and the main body 1 are pressed against each other via the seat ring 2 is formed by the rotation center axis 3a of the valve rod 3. The feature is that it matches.

[0004] The center type butterfly valve having the above structure has the following features. 1) Since the main body does not come into contact with liquid, economical main body material can be used. Even if the inner surface is damaged, it can be recovered by replacing the seat ring. 2) Compared to the eccentric type, the number of components is small and it is economical. 3) No gasket is required for connection with piping. 4) When a fluid pressure is applied, it acts in a direction to lower the sealing surface pressure between the valve body and the seat ring, so that it is difficult to seal at a high pressure. 5) The vicinity of the valve stem penetration portion of the valve body is in contact with the seat ring both when closed and when opened, which causes an increase in torque and a shortened life. 6) As shown in FIG. 4, the contact between the valve body and the seat ring is
Since the contact area is different between the portion A near the valve stem penetrating portion and the portion B around the circumference, the sealing surface pressure is not constant over the entire circumference, which causes unstable sealing at the boundary between the portion B and the boundary between A and B. Has become.

On the other hand, FIG. 3 shows a typical structure of an eccentric butterfly valve, and is a vertical sectional view of a wafer type eccentric butterfly valve in a fully closed state. In the figure, a valve body 6 eccentric to a valve stem 3 penetrating the center of a main body 1 is attached by a connecting pin 4 via two vertically formed eccentric support members 6a. The eccentric support members 6 a are engaged and supported on the inner peripheral surface of the main body 1 via the spacers 7 in order to hold the valve body 6 at the center position of the inner peripheral surface of the main body 1.

In the valve body 6, a seat ring 8 made of an elastic material is formed at the downstream end of the main body 1 so as to abut on the outer peripheral edge of the valve body 6 at the fully closed position (position shown). The outer side thereof is pressed by a seat retainer (holding body) 9 and is fixed to one downstream side of the main body 1. When the valve is closed, the contact surfaces of the two are formed to be inclined so that the valve body 6 is pressed against the seat ring 8 by receiving the fluid pressure in the direction of arrow A. In the figure,
Reference numeral 10 denotes a shaft sealing member, and 1b denotes a bottom cover.

In the illustrated eccentric butterfly valve, when the valve body 6 is in the fully closed position, the seal surface against which the outer peripheral edge of the valve body 6 and the main body 1 press against each other via the seat ring 8 is rotated by the rotation of the valve rod 3. It is characterized in that it does not coincide with the central axis 3a.

The eccentric butterfly valve having the above structure has the following features. 1) Since the main body comes into contact with the liquid, a material of the main body having corrosion resistance is required. Damage to the inner surface is the life of the valve itself. 2) Compared to the central type, the number of components is large, the structure is complicated, and it tends to be expensive. 3) Since the fluid pressure acts in the direction of pressing the valve body against the seat ring, a relatively high pressure can be sealed. 4) The valve element is in close contact with the seat ring when the valve is closed, but does not contact the seat ring when the valve is open. 5) The contact of the seat ring of the valve body can be made with the same surface pressure throughout the circumference when fully closed. The contact area between the valve body and the seat ring is
It is the same all around. 6) A gasket is required for connection with piping.

[0009]

As described above, the conventional center type butterfly valve and the conventional eccentric type butterfly valve have advantages and disadvantages, respectively.

That is, the center type butterfly valve is economical, but is not suitable for high pressure use, and a part of the valve body (the valve stem penetrating portion) is in contact with the seat ring regardless of whether it is open or closed. As a result, the torque and the sealing performance were hindered.

On the other hand, the eccentric butterfly valve is capable of high-pressure sealing, has no contact between the valve body and the seat ring at the time of opening, is excellent in torque and sealing properties, but is expensive due to its complicated structure and piping. Handling was troublesome, such as the need for a gasket to connect to the device.

In order to take advantage of and compensate for the disadvantages of both types of butterfly valves as described above, a main body having an axial flow path and a main body having an axial flow path are disposed in a plane perpendicular to the flow path when the valve is closed. (A cross section perpendicular to the valve stem has a triangular shape) and cooperates with the peripheral seal (sealing) surface of the valve disc by deviating in the flow direction from the valve stem penetrating the main body. A valve seat having first and second annular seal contact areas which are parallel to each other and are located on opposite sides with a valve stem inserted therein, twice the axial offset distance of the disc. When one of the two valve seats (main valve seat) is damaged or worn, the valve disc is rotated by 180 ° and the new alternate valve seat is used. A butterfly valve has been already devised that doubles the life of the valve.
No. 5584).

However, also in this case, the valve stem which is driven to rotate through the valve disc has a structure in which the valve stem is inserted and supported in the main body through a seat ring constituting a valve seat. As with the conventional center type butterfly valve, the valve body is in contact with the seat ring both when the valve is open and when the valve is closed. There is a problem that the life is shortened.

The present invention provides a butterfly valve which has the advantages of the conventional center type butterfly valve and the eccentric type butterfly valve described above, and which eliminates the above-mentioned problems of the known butterfly valve already devised. It is an issue.

[0015]

Means for Solving the Problems In order to solve the above-mentioned problems, a means adopted by the present invention is to provide an annular seat ring made of an elastic material which cooperates with an outer peripheral portion of a valve body to perform a sealing function. In the butterfly valve mounted on the valve body, an annular seat ring made of an elastic material is mounted on the inner peripheral surface of the main body so as to cover the inner peripheral surface, and the valve stem is inserted through the seat ring and supported by the main body. The valve body is eccentrically mounted via an eccentric support member which comes into contact with the inner surface of the seat ring via a spacer.

Further, a valve stem penetrating the seat ring is penetrated at a position shifted from the center of the seat ring.

Further, spacers provided on both upper and lower end surfaces of an eccentric support member for eccentrically mounting the valve element to the valve stem, and having a radially-reduced annular member fitted to the valve stem, the spacer being in contact with the inner surface of the seat ring. It is characterized by being formed by.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the embodiments shown in the drawings. FIG. 1 is a vertical cross-sectional view including a valve shaft center axis of a butterfly valve in a fully closed state, showing one embodiment (example) of the present invention.

In the figure, an annular elastic seat ring 12 made of an elastic material such as rubber is provided on an inner peripheral surface of a main body 11, and ear portions 12 a formed on both sides thereof are formed in annular concave portions formed on both side surfaces of the main body 11. And are fixed to the main body 11 by being engaged with each other. On the inner peripheral surface of the seat ring 12, when fully closed, an inclined surface portion 12c abutting on an inclined surface portion 14b formed on an outer peripheral edge of a valve body 14 mounted eccentrically on the valve rod 13 is provided from the valve rod penetrating portion. Since it is formed on the downstream side, the valve stem 13 penetrates at a position shifted from the center of the full width along the flow path of the seat ring 12 to the upstream side.

The main body 11 seals an internal pressure at a seal point 12b formed of an O-ring or the like (not shown) formed at a portion of the seat ring 12 through which the valve rod 13 passes.
No corrosion resistance is required, and a seal structure such as a shaft sealing device (10 in FIG. 3) of a conventional eccentric butterfly valve is not required on the main body 11 side. As with the center type butterfly valve, the purpose is to hold the seat ring and the overall rigidity, and is made of a carbon steel material such as a casting or a steel material. Also, the seat ring 12
Has a role of holding a valve seat seal, a valve stem seal, a pipe connection seal, and a valve body at a center position, and is usually made of a rubber material.

As described above, the valve element 14 is mounted eccentrically on the valve rod 13 penetrating the center of the main body 11 by the connecting pin 15 via the two upper and lower eccentric support members 14a. Spacers 16 for holding the valve body 14 at the center of the seat ring 12 are provided on both upper and lower end surfaces of the eccentric support member 14a. The valve element 14 is
A material that is not affected by the internal fluid is used, and is made of a casting such as carbon steel or stainless steel, or a steel material. Similarly, the valve stem 13
Is also made of a material that is not affected by the internal fluid. The coupling pin 15 transmits the torque of the valve rod 13 to the valve element 14, and may be a key, a bolt, serration between the valve rod and the valve element, or a square joint, in addition to the pin type. Also, the spacer 16
Is generally formed as an annular body having a reduced thickness in the radial direction fitted to the valve stem, and is interposed separately from the eccentric support member 14a, but may be integrated.

Next, the operation will be described. When the valve is fully closed as shown in FIG.
4a is in close contact (contact) with the inclined surface portion 12c of the seat ring 12, and the valve body 14 is further pressed against the inclined surface portion 12c of the seat ring by fluid pressure from the direction of arrow A to be in pressure contact with the valve member. Seat sealing is realized.
On the other hand, leakage of the fluid along the valve rod 13 is sealed (sealed) by a seal point 12b of the seat ring 12 through which the valve rod 13 penetrates, which is formed by an O-ring (not shown) or the like.

Next, when the valve element 14 is rotated by the valve rod 13 in the opening direction from the fully closed state, the inclined surface portion 14b on the outer peripheral edge of the valve member is separated from the inclined surface portion 12c of the seat ring 12, and the entire periphery is seat ring. 12 and the valve element 14 pivots about the central axis 13a of the valve stem and
Open the flow path. At this time, the rotating valve body and the inner surface of the seat ring 12 only come into contact with each other via the spacer 16. Since the spacer 16 is used for holding the position of the valve element 14 and does not require a sealing function, the spacer 16 does not bite into the seat ring as in the center type butterfly valve (FIG. 2).

Therefore, the vicinity of the valve stem penetrating portion of the valve element 14 contacts only a small area via the spacer 16 both when the valve is closed and when the valve is opened. Not only does it require less torque, it also has a longer life because of less wear due to contact.

[0025]

As described above, according to the present invention,
In a butterfly valve in which an annular seat ring made of an elastic material having a sealing function in cooperation with an outer peripheral edge of a valve body is attached to a main body, an inner peripheral surface of the main body is covered with the elastic material so as to cover the inner peripheral surface. An annular seat ring is attached, and the valve body is eccentrically attached to the valve stem that is inserted through the seat ring and inserted into the main body and supported by an eccentric support member that is in contact with the inner surface of the seat ring via a spacer. As a result, the following effects can be obtained.

(I) When the valve is opened, the pressure contact between the valve body for sealing the valve seat and the seat ring is completely released, so that the vicinity of the valve stem penetration portion of the valve body is seated both when the valve is closed and when the valve is opened. Compared to a central butterfly valve in contact with the ring, there is no extra contact movement and less torque for valve stem rotation. Further, since there is no rotation while rubbing the seat ring, deterioration of the seat ring can be minimized.

(Ii) Since the main body does not come into contact with liquid and does not require a material having high corrosion resistance, an economical material similar to the center type butterfly valve can be used. Further, the number of components is smaller than that of the eccentric butterfly valve (FIG. 3), and can be equivalent to that of the center butterfly valve (FIG. 2), so that an economical component configuration can be realized.

(Iii) When fully closed, the internal pressure applied to the valve body is
Since the valve element is displaced in the direction in which the valve element is brought into close contact with the seat ring, compared with the center type butterfly valve, even a component made of the same material can seal a structurally high pressure.

(Iv) No gasket is required for pipe connection.

(V) The contact between the valve body and the seat ring for sealing the valve seat can have the same area and the same amount of compression over the entire circumference, so that stable sealing performance can be ensured at any part. .

Further, by passing the valve stem penetrating through the seat ring at a position shifted from the center of the seat ring, the design of the seat ring closely contacting the outer peripheral edge of the eccentric valve body is facilitated.

Further, since the spacer provided on the end face of the eccentric support member is formed of an annular body having a reduced thickness in the radial direction, the contact friction resistance with the inner surface of the seat ring can be reduced, so that the rotation of the valve body is achieved. The torque and the wear of the part are small.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a butterfly valve showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a conventional center type butterfly valve.

FIG. 3 is a longitudinal sectional view of a conventional eccentric butterfly valve.

FIG. 4 is an explanatory drawing of a valve body of a conventional center type butterfly valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main body 12 Seat ring 12a Ear 12b Seal point 12c Inclined surface part which comes in close contact with a valve body 13 Valve stem 13a Valve stem center line 14 Valve body 14a Eccentric support member 14b Inclined surface portion of valve body outer peripheral edge 15 Joint pin 16 Spacer

Claims (3)

[Claims] 1. A butterfly valve having an annular seat ring made of an elastic material which cooperates with an outer peripheral edge portion of a valve body and having a sealing function mounted on a main body, wherein the inner peripheral surface of the main body covers the inner peripheral surface. An annular seat ring made of an elastic material is attached to the valve, and the valve is inserted through an eccentric support member that is in contact with the inner surface of the seat ring through a spacer on a valve rod that is inserted through the seat ring and supported by the main body. A butterfly valve characterized in that the body is mounted eccentrically. 2. The butterfly valve according to claim 1, wherein a valve stem penetrating the seat ring is penetrated at a position shifted from a center of the seat ring. 3. An annular body provided on both upper and lower end faces of an eccentric support member for eccentrically mounting a valve body to a valve stem, and having a spacer in contact with an inner surface of a seat ring and having a reduced radial thickness fitted to the valve stem. The butterfly valve according to claim 1, wherein the butterfly valve is formed by: