JP2002372158A - Center type butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To concurrently satisfy wear resistance, tensile strength, and tear strength in the physical characters of a seat ring of a conventional butterfly valve, elongate service life of the seat ring, and provide more positive sealability by a comparatively simple structure. SOLUTION: The butterfly valve is composed of a valve body 1 comprising a rigid material piercing a cylindrical fluid channel, a discoidal valve element 3 comprising a rigid material rotatably journalled inside the valve body 1, and the seat ring 2 comprising an elastic material stretched between the valve body 1 and the valve element 3. Both side end faces d of the seat ring 2 provided on the valve body 1, and outer circumferential faces e and inclined faces f of both side end faces are integrated with the valve body 1. A gap part 5 is provided between the valve body 1 and cylindrical outer circumferential faces formed in inner end parts of both inclined faces f of the seat ring 2. A conduit 6 supplying and discharging operating fluid is communicated with the gap part 5. Reinforcing woven fabrics 2a are concurrently formed in a back side of the seat ring 2 in portions not pressed against the valve element during valve closing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve used for opening and closing and controlling a fluid, and more particularly to a center type butterfly valve for reducing a valve shaft torque when the valve is closed or opened.

[0002]

2. Description of the Related Art FIG. 3 is an enlarged view of a main part of a basic structure of a conventional center type butterfly valve. The figure shows a cylindrical valve body 1, a disk-shaped valve body 3 rotatably supported in the valve body 1,
When the valve is closed, it comprises a seat ring 2 stretched between the valve body 1 and the peripheral edge of the valve body 3. 2 shows a state in which the abutment is in contact with the inner peripheral surface.

FIG. 4 is an enlarged view of the portion A in FIG. 3, and FIGS. 4A to 4C show the manner of change in the contact between the valve body and the seat ring.

FIG. 4A shows that the valve body 3 is rotated clockwise, and immediately after the valve body 3 comes into contact with the seat ring 2, the inlet side (point A) of the seat ring 2 is pulled, and the opposite side (point B) is pulled. It is an assumption figure showing the state where it was compressed. That is, the inlet side seat ring is slightly moved to the opposite side by the rotation of the valve body 3.

Next, FIG. 2B shows that the seat ring slightly moved from the state shown in FIG. 2A returns to its original position with the passage of time, and the seat ring is almost evenly distributed on the outer peripheral edge of the valve body. Will be pressed against.

Next, FIG. 3C shows a state immediately before the valve body 3 is turned counterclockwise from the state shown in FIG.
Is an assumed diagram showing a state where the outlet side (point B) is compressed and the opposite side (point A) is pulled. That is, the rotation of the valve body 3 causes the outlet side seat ring to be slightly compressed and rise inward.

As described above, the vicinity of the contact portion between the seat ring and the valve element is caused by the rotation of the valve element, that is, the parts (points B and A) which are in a compressed and tensioned state when the valve is closed (FIG. 1A). )But,
When the valve is opened (Fig. (C)), it is in a tensioned and compressed state and performs the opposite operation.

Accordingly, when the valve is frequently opened and closed, a seat ring (elastic body) is provided near the contact portion of the seat ring.
, The physical properties, ie, rebound resilience, compression set, tensile strength, etc. Impurities in the fluid,
The mixture of dust, solids, and the like will promote abrasion of the seat ring.

Normally, the seat ring is made of an elastic material (e.g., vulcanized rubber), and performs a sealing action due to the resilience inherent to the material. Therefore, the life of an excellent elastic material depends on the specification conditions.

The fluid is generally a liquid (seawater, industrial water,
Oil, etc.) are mainly divided into gases (air, oxygen, etc.) and powders. Therefore, it is clear that a uniform seat ring material cannot be used. In particular, the life of the seat ring is significantly affected by the pressure and temperature of the fluid.

As described above, it is necessary to select a material suitable for the fluid for the seat ring.
Periodically replace the seat ring according to the period of use, etc. (Easily damaged among the butterfly valve parts)
Supports sheet leakage prevention. As described above, the life of the butterfly valve is currently determined by the wear of the seat ring, so to extend the life of the butterfly valve,
An important issue is how to prevent seat ring wear.

For this reason, in the prior art, measures have been discussed, such as thoroughly examining the wear resistance among the physical properties of the seat ring material and minimizing the press-contact amount as much as possible.

In order to cope with these problems, a watertight rubber is stretched in a groove formed in the inner periphery of the valve body, and the watertight rubber is formed in the peripheral surface of the valve body by pressure water through the groove. There has been invented a non-sliding watertight device which can be pressed or detached from a sealed groove (see Japanese Patent Publication No. Sho 51-10687).
When the valve body shuts off the pipe, the watertight rubber is laid down in the watertight rubber working chamber, and the valve body is driven without sliding with the watertight rubber to the fully closed position. The pipe is closed by pressure water in close contact with the seal groove on the outer periphery of the valve body.On the other hand, when the pipe line is opened, the close contact of the seal groove is released to bring the valve body into contact with the watertight rubber. It is driven to the fully open position without sliding.

[0014]

When the wear resistance is improved among the physical properties of the seat ring material, other physical properties such as tensile strength, tear strength, There is a problem in that the hardness or the like is reduced, and thus it cannot be always applied as a seat ring of a butterfly valve, and when the amount of pressure contact is reduced, the sealing property is reduced and the function as a valve cannot be achieved.

The present invention extends the life of the seat ring by simultaneously satisfying the wear resistance, tensile strength, and tear strength among the physical properties of the seat ring of the conventional butterfly valve, extending the life of the seat ring, and using a relatively simple structure. It is a technical task to further ensure the sealing performance.

[0016]

In order to solve the above-mentioned problems, a means adopted by the present invention is to provide a valve body made of a rigid material having a cylindrical fluid passage penetrating therethrough, and a valve body pivoted in the valve body. A butterfly valve comprising a disc-shaped valve body made of a rigid material freely supported on a shaft and a seat ring made of an elastic material stretched between the valve body and the valve body. The two side end surfaces of the provided seat ring, the outer peripheral surface and the inclined surface of the both end surfaces are integrally joined to the valve body, and a cylindrical outer peripheral surface formed at the inner end of the two inclined surfaces of the seat ring. A gap is provided between the valve body and the valve body, and a conduit for supplying and discharging the operating fluid is communicated with the gap.

Further, a reinforcing woven fabric is simultaneously formed on a portion of the back side of the seat ring which is not pressed against the valve body at the time of valve closing, and the center portion of the inner peripheral surface on the front side of the seat ring is thick. It has a middle-high structure and features a curved surface when pressed against the valve element.

A plurality of conduit ports for supplying / discharging the operating fluid to / from the gap are provided at a plurality of locations on the valve body, and three or more ports are provided near them.
It is characterized in that the supply / discharge action is switched by a port switching valve.

[0019]

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 configuration diagram of a butterfly valve according to an embodiment of the present invention when the butterfly valve is closed. Although the pneumatic operation type is used as the valve driving actuator in this embodiment, other actuators perform the same operation.

FIG. 2A is an enlarged sectional view of a main part when the valve is closed, and FIG. 2B is a developed view of the seat ring in FIG. 2 shows the arrangement of the reinforcing woven fabric depicted in FIG.

In the figure, both side end surfaces d of a seat ring 2 stretched over a valve body 1, outer peripheral surfaces e and inclined surfaces f of the both side end surfaces d are integrally joined to the valve body 1,
A gap 5 is formed between the cylindrical outer peripheral surface formed at the inner end of each of the inclined surfaces f and the valve body 1, and the operation fluid is supplied to and discharged from the gap 5. Conduit 6 is communicated.

A plurality of the conduits 6 are provided around the valve body 1 at substantially equal intervals, and the supply / discharge operation is switched by one or more three-way switching valves (not shown).

Next, the operation will be described with reference to FIG.
In (a), the seat ring 2 shown by a solid line indicates the position (state) immediately after the valve body 3 is at the valve closing position, and the seating torque has reached zero at this position due to the gap c. Become.

Next, the operating fluid is supplied by a three-way switching valve (not shown) provided in the vicinity of the valve body 1 so that the seat ring 2 is inwardly inward from the gap 5 through the conduit 6. Expands, comes into contact with the gap c, and stops expanding with a slight interference. This is indicated by the dotted line. The supply pressure is preferably 0.19 to 0.39 (MPa, megapascal), and the interference is preferably about 1/10 of the seat ring thickness.

When the seat ring 2 expands inward, the contact points a and b between the seat ring and the valve body become the base points for tension and compression of the seat ring 2.
In this area, as shown in FIG. 2 (b), a reinforcing woven fabric 2a is integrally vulcanized to the working fluid side. The reinforcing woven fabric 2a includes polyester, nylon, and tetron.
In addition, the central portion of the inner peripheral surface of the seat ring 2 has a middle-high structure, and the sealing performance is further improved by pressing the curved surface when pressing the valve ring 3 against the valve body 3.

Further, the actuator 7 shown in FIG. 1 is constituted by a pneumatically operated actuator in which the rotation of a valve body (valve rod) is driven by a pneumatically operated piston, and the actuator is not shown. The seat ring 2 is actuated by a four-way switching valve, while being deformed by a three-way switching valve provided in a conduit leading to the back side of the seat ring, to a position indicated by a dotted line and a solid line. However, it is also possible to perform automatic operation control by synchronizing the four-way switching valve of the actuator and the three-way switching valve of the seat ring.

Next, an example of a state of each valve when the two switching valves are synchronized is shown in a table as follows.

[0028]

[0029]

As described above, according to the present invention,
A valve body made of a rigid material penetrating a cylindrical fluid passage, a disc-shaped valve body made of a rigid material rotatably supported in the valve body, and a valve body and the valve body. In the butterfly valve formed of a seat ring made of an elastic material stretched on the valve body, both end surfaces of the seat ring stretched on the valve body, outer peripheral surfaces of the both end surfaces and an inclined surface are integrally joined to the valve body. A gap is provided between the valve body and a cylindrical outer peripheral surface formed at the inner ends of the two inclined surfaces of the seat ring, and a conduit for supplying and discharging the operation fluid to and from the gap is provided. The communication has the following effects.

(I) Since both end surfaces, the outer peripheral surface, and the inclined surface of the seat ring are integrally joined to the valve body, even if the inward expansion by the operating fluid is repeatedly performed, the dangerous parts are integrated, The sealing life of the seat ring, that is, the service life of the butterfly valve can be extended.

(Ii) Since a gap is provided between the valve body and the cylindrical outer peripheral surface formed at the inner ends of the inclined surfaces on both sides of the seat ring, the operating fluid locally covers the outer peripheral surface of the seat ring. It is possible to expand inward from the entire circumference simultaneously without any pressure.

(Iii) The seating expansion actuator (3-way switching valve) maximizes the seating torque, that is, a large torque value required when the valve element presses or separates from the seat ring at the time of fully closing and opening the valve. It becomes zero, the size of the valve drive actuator can be reduced to a large size, the assembly dimensions are small, the size can be reduced, the weight can be reduced, and the cost can be reduced significantly.

(Iv) Along with the above-mentioned maximum zero of the seating torque, the wear near the pressure contact portion of the seat ring is greatly reduced, and the life can be extended.

(V) Good results can be obtained for the specification with a high frequency of valve opening / closing, and it is suitable for small and medium bores with valve sizes of 50 to 200 A and has great durability and cost merit.

Further, by forming a reinforcing woven fabric simultaneously on the back side of the seat ring which is not pressed against the valve body at the time of closing the valve, the contact between the seat ring and the valve body when the seat ring expands inward. Since a and b are the base points of the tension and compression of the seat ring, the portion is further reinforced by the reinforcing woven fabric integrally vulcanized on the back surface of the portion. That is, the durability and the life of the butterfly valve can be further increased.

In addition, since the central portion of the inner peripheral surface of the seat ring has a middle-high structure, it comes into contact with the curved surface when pressed against the valve body, and the sealing effect can be further enhanced.

Also, automatic operation is possible by synchronizing the four-way switching valve of the valve driving actuator with the three-way switching valve for expanding the seat ring.

[Brief description of the drawings]

FIG. 1 is an overall front view showing a central butterfly valve according to an embodiment of the present invention when the valve is closed.

FIG. 2A is an enlarged sectional view of a main part when a valve is closed. FIG. 2B is a development view of the seat ring in FIG.

FIG. 3 is an enlarged sectional view of a main part of a basic structure of a conventional center type butterfly valve.

4A and 4B are enlarged views of a portion A in FIG. 3, wherein FIG. 4A shows a state immediately after abutment of a valve body and a seat ring, FIG. 4B shows a state after a lapse of time, and FIG. The aspect immediately before the movement is shown.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve main body 2 Seat ring 2a Reinforcing woven cloth 3 Valve body 4 Valve stem 5 Gap part 6 Conduit 7 Actuator a Base point b Base point c Gap d End face (both sides) e Outer peripheral face f Slope A Pulling part B Compressing part

Claims (4)

[Claims] 1. A valve body made of a rigid material penetrating a cylindrical fluid passage, a disc-shaped valve body made of a rigid material rotatably supported in the valve body, and a valve body. In a butterfly valve formed of a seat ring made of an elastic material stretched between a valve body, the both end surfaces of the seat ring stretched on the valve body, the outer circumferential surface and the inclined surface of the both end surfaces,
A gap is provided between the valve body and the cylindrical outer peripheral surface formed at the inner ends of the two inclined surfaces of the seat ring, and an operation fluid is supplied to the gap. Center type butterfly valve characterized by communication of inlet and outlet conduits. 2. The center type butterfly valve according to claim 1, wherein a reinforcing woven fabric is formed simultaneously on a portion of the back side of the seat ring which is not pressed against the valve body when the valve is closed. 3. The center type butterfly valve according to claim 1, wherein the central portion of the inner peripheral surface on the front side of the seat ring has a thick middle-high structure, and is brought into contact with a curved surface when pressed against the valve body. . 4. A valve body is provided with a plurality of conduit ports for supplying and discharging the operation fluid to and from the gap, and the supply / discharge operation is switched by a three-way switching valve provided in the vicinity thereof. The center type butterfly valve according to claim 1, 2 or 3, wherein: