JPH0814330B2 - Butterfly valve and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of use) The present invention comprises a valve body formed of a hollow cylindrical metal tube having an inner peripheral surface composed of two layers, a tetrafluoroethylene resin layer and an elastic elastomer layer. The present invention relates to a butterfly valve, which is covered with a lining layer, and integrally formed with a valve seat having a disc-shaped outer peripheral edge of a valve body coming into contact with and separated from the lining layer, and a manufacturing method thereof.

(Prior Art) Conventionally, a valve body of a butterfly valve is formed by casting, an elastic valve seat called a seat ring is attached to the inner peripheral surface of the valve body, and the valve body is rotatably supported in the valve body. A butterfly valve is known in which the valve is opened and closed by the contact and separation of the disc-shaped outer peripheral edge of the valve body and the valve seat.

However, the valve body formed by casting is
Since it is heavy and inconvenient to handle, it was unsuitable for directly lining the seat ring on the inner peripheral surface of the valve body by molding using a mold.

In addition, casting processing is difficult to obtain because of various adverse conditions such as deterioration of environment, shortage of skilled engineers, and large number of processing steps, leading to an increase in product price. It is in.

When touch resistance and chemical resistance are required as usage conditions of butterfly valves, seat rings are made of tetrafluoroethylene resin.
Since it itself has no elasticity, there is a problem of how to add elasticity to improve the sealing property, and since it is expensive, it is necessary to make the thickness as thin as possible from an economical point of view. However, since it is thin, it is necessary to reinforce it.

(Problems to be Solved by the Invention) The present invention aims to solve the problems existing in the case of forming a valve body by conventional casting and the problems occurring in the case of forming a seat ring from tetrafluoroethylene resin. It is a thing.

(Means for Solving the Problems) In order to solve the above problems, the means adopted by the first invention is a valve main body made of a hollow cylindrical metal tube having a predetermined length in the axial direction, and the valve main body. Lining layer that covers the inner peripheral surface and the end surface of the valve body, and a disk-shaped valve body that is rotatably supported in the valve body. An opening is provided, and a valve rod guide is fixedly connected to the opening, and a valve rod that pivotally supports the valve element is inserted into the valve rod guide, and one valve rod is connected to a driving means so that it is outside the valve rod guide. And the other valve stem ends in the valve stem guide, and the lining layer has a valve seat at its center portion which extends in the circumferential direction and which is brought into contact with and separated from the outer peripheral edge of the valve body.
It is characterized by being formed from a tetrafluoroethylene resin layer and an elastic elastomer layer.

A second invention is a method for manufacturing the butterfly valve according to the first invention, which comprises a molded product of tetrafluoroethylene resin sheet molded in advance into a shape substantially matching the inner surface shape of the lining layer. After being inserted and set in the mold, the mold and the valve body are set in position by the outer diameter of the mold and the jig that is inserted into the shaft hole, and then set, and unvulcanized rubber is injected and vulcanized to form the lining layer. Is formed.

(Embodiment) A preferred embodiment of the present invention will be described in detail below with reference to the drawings. In the figure, (1) is a valve body of a butterfly valve, which is composed of a hollow cylindrical metal tube body, and axial holes (2) and (2) are bored at diametrically opposed positions at a central position in the axial direction. Valve rod guides (3) and (4), which extend continuously outward from the holes (2) and (2), are fixed.

The hollow cylindrical metal tube body forming the valve body (1) can be most easily obtained, for example, by cutting a commercially available long steel pipe for piping into a predetermined length. Such steel pipes for piping have the same outer dimensions when the nominal diameter is the same regardless of the use and the material, so it is easy to match the outer diameters of the valve main body and the piping line. And
The butterfly valve can be connected to the pipeline by using a simple connecting means such as a fastening band or a joint, so that the connection cost can be reduced and the workability can be improved. The valve rod guides (3) and (4) are made of steel pipe having a required diameter and can be fixed to the valve body (1) by welding.

The inner peripheral surface and both end surfaces of the valve body (1) are covered with a lining layer (5). The lining layer (5) is composed of a two-layer body of a tetrafluoroethylene resin layer (6) located on the inner side of the valve and an elastic elastomer layer (7) located on the outer side of the valve,
The tetrafluoroethylene resin layer (6) and the elastic elastomer layer (7) are bonded and integrated with each other, and
The elastic elastomer layer (7) is firmly bonded to the inner peripheral surface and the end surface of the valve body (1).

A valve seat (8) extending annularly in the circumferential direction is formed at the center of the inner peripheral surface of the lining layer (5). The valve seat (8) is formed in the shape of a circular arc recessed toward the center of the valve, and the curvature of the circular arc matches the curvature of the circular arc of the outer peripheral edge of the valve body (9) that comes into contact with and separates from the valve seat (8). Has an inner diameter slightly smaller than the outer diameter, and the valve body (9) is brought into contact in a pressure contact state in order to close the fluid.

The valve body (9) has a disc shape, and valve rods (10) and (11) are fixed at diametrically opposed positions, and extend outward. The valve rods (10) (11) are axially inserted in the valve rod guides (3) (4) to rotatably support the valve body (9) in the valve body (1), and one valve rod (10) extends outwardly from the outer end of the valve rod guide (3) and can be connected to an appropriate drive means.
The other valve rod (11) ends in the valve rod guide (4), and the outer end of the valve rod guide (4) is closed by a cover plate (12). Appropriate sealing means such as a gland packing is provided between the valve stem guides (3) and (4) and the valve stems (10) and (11) axially mounted on the valve stem guides, and a gap between the valve stem guide and the valve stem is provided. Prevents uneven leakage of fluid from.

In the illustrated embodiment, the valve stem is split into two valve stems (1
Although 0) and (11) were fixed to the valve body (9) in a non-rotating state,
It goes without saying that a single valve rod may be inserted into the valve body and connected to prevent rotation.

The tetrafluoroethylene resin layer (6) constituting the lining layer (5) has a thin thickness, is economical, and has elasticity imparted by the elastic elastomer layer (7).
And the strength is reinforced. Thus, the lining layer (5) has improved sealability as well as good contact resistance and chemical resistance, so that the restriction due to the fluid used is eliminated, and a butterfly valve having a seat ring suitable for almost all fluids can be used. Can be provided.

A preferred method of forming the lining layer (5) on the valve body (1) will now be described with reference to FIGS.

For the lining layer (5), a molding die is set on the valve body (1) to which the valve rod guides (3) and (4) are fixed, and a molding of tetrafluoroethylene resin molded in a predetermined shape is molded. It is formed by arranging it inside and further injecting and vulcanizing unvulcanized rubber.

Mold for molding is divided into first and second molds (13).
(14) and an unvulcanized rubber injection mold (15). The first mold (13) has a valve seat molding part (16) for molding the valve seat (8). The valve seat molding part (16) has a cylindrical part (17) having an upper end and a flange part (19) continuous to the lower end of the cylindrical part (17) through a groove part (18) having a cross section. A jig insertion hole (20) penetrating in the diameter direction is formed. The valve seat molding portion (16) is formed in an arcuate projection shape corresponding to the arcuate shape of the valve seat (8). The cylindrical portion (17) has an outer diameter smaller than the inner diameter of the valve body (1) by the thickness of the lining layer (5), and when set, between the inner peripheral surface of the valve body (1) and the inner surface. Then, a gap corresponding to the thickness of the lining layer (5) is formed. The groove (18) has a depth capable of forming a gap corresponding to the thickness of the lining layer (5) from the end face (1a) of the valve body (1), and the inner diameter of the flange (19) continuous to this is the valve. When the flange (19) is fitted to the outer circumference of the end of the valve body (1) in conformity with the outer diameter of the body (1), the first mold (1
3) is set to the valve body (1) without causing radial play.

The second mold (14) has a cylindrical part (21) stacked on the upper surface of the first mold (13) and a groove (22) having a cross section at the upper end of the cylindrical part (21). A continuous flange portion (23) is provided, and the cylindrical portion (21), the groove portion (22), and the flange portion (23) have the same structure as the first mold and have the same action. The second mold (14) is further opened in the groove (22), and a plurality of injection holes (24) for injecting unvulcanized rubber are formed along the circumferential direction.

The injection mold (15) is a mold for fitting the second mold (14) and introducing unvulcanized rubber into the injection hole (24). It has an injection port (25) connected to a sulfur rubber injection device, and an injection passage (26) from the injection port (25).
Extends and communicates with the injection hole (24) of the second mold (14).

(27) is a jig and has a rod shape having the same diameter as the valve rods (10) and (11), and is formed from the valve rod guides (3) and (4) to the first die (1).
Insert it into the jig insertion hole (20) in 3), and then insert it into the first mold (13).
Is accurately set at an axial position with respect to the valve body (1).

Thus, the first mold (13) set in the valve body (1) is axially positioned by inserting the jig, and the flange portion (19) and the valve body (1) are fitted together. A diametrical positioning is achieved.

(28) is a molded product made of a thin tetrafluoroethylene resin sheet and has a shape substantially corresponding to the tetrafluoroethylene resin layer (6) of the lining layer (5). That is, a cylindrical portion (29) corresponding to the inner peripheral surface shape of the valve body (1) and a valve seat corresponding portion (30) located at the center of the cylindrical portion (29) and corresponding to the shape of the valve seat (8). , And flange portions (31) at both ends, and an opening (32) corresponding to the shaft hole (2) is formed in the valve seat corresponding portion (30), and the ring (33) is formed from the opening (32). ) Extends outward. The ring (33) has a length corresponding to the thickness of the elastic elastomer layer (7) of the lining layer (5), and in the molded state, the inserted valve rods (10) (11) are It comes into contact with the fluorinated ethylene resin layer (6) so that the elastic elastomer layer (7) does not directly come into contact with the valve rods (10) and (11).

The tetrafluoroethylene resin sheet molded product (28) is formed in a shape that substantially matches the shape of the inner peripheral surface of the lining layer (5), and is used in the first and second molds during the unvulcanized rubber injection step. (1
3) The lining layer (5) is formed by fitting the unvulcanized rubber injected into the outer periphery of (14).

Although the tetrafluoroethylene resin sheet is hard at room temperature,
When heated, it softens and becomes the first and second molds (13) (14)
It fits in the shape of and is molded into an accurate shape. Therefore, it is not necessary to previously mold the molded product (28) into an accurate shape.

Referring to FIG. 7, the valve body (1) is fitted into the flange portion (19) of the first mold (13) in which the tetrafluoroethylene resin sheet molded product (28) is inserted and set, and the jig is set. (27) is inserted into the jig insertion hole (20) from the valve rod guides (3) and (4), and the valve body (1) is set in the first metal fitting (13). in this case,
The molded product of tetrafluoroethylene resin sheet (28) is the valve body (1).
Located inward of. Next, while inserting the second mold (14) into the tetrafluoroethylene resin sheet molded product (28), the second mold (14) is stacked on the first mold (13), and the flange portion (23) is attached to the valve body ( Fit the end of 1) and set the second mold (14). Finally, the injection mold (15) is fitted and set on the upper part of the second mold (14) while aligning the injection hole (24) with the injection passage (26).

After setting the three molds (13), (14) and (15) in this way, unvulcanized rubber is injected from the injection port (25).
The unvulcanized rubber injected into the first and second molds (13) passes through the injection passage (26) and the injection hole (24) as shown in FIG.
It is injected into the gap between the tetrafluoroethylene resin sheet molded product (28) inserted on the outer peripheral surface of (14) and the inner peripheral surface of the valve body (1) to fill it. By the injection, as shown in FIGS. 10 and 11, the internal air is exhausted to the outside through the gap between the flange portion (19) and the valve body (1), and the completion of the injection is known by the outflow of unvulcanized rubber. After the injection, remove the injection mold (15) and heat to proceed with vulcanization. After the vulcanization is completed, the second mold (15) is pulled out upward, and the jig (27) is pulled out.
The valve body (1) is taken out of the first mold (13) and the rubber in the injection hole (24) is removed to obtain a finished product.

By vulcanization, tetrafluoroethylene resin sheet molding (28)
Is softened and shaped into a predetermined shape, combined with the injected unvulcanized rubber and integrated to form a lining layer (5) for covering the inner peripheral surface and the end surface of the valve body (1). )
Are combined and integrated into.

An adhesive is applied to the outer peripheral surface of the molded product (28) to bond the tetrafluoroethylene resin sheet molded product (28) and the elastic elastomer, and at the same time, to the inner peripheral surface and the end surface of the valve body (1). An adhesive is applied to bond the elastic elastomer and the valve body (1). A mold release agent is applied to the inner and outer surfaces of the molds (13) and (14) to prevent the elastic elastomer from adhering.

(Function) Since the metal valve body inner peripheral surface is covered with the tetrafluoroethylene resin layer through the elastic elastomer layer,
The metal having poor affinity and adhesiveness can be strongly bonded to the tetrafluoroethylene resin, and the formed lining layer has improved contact resistance and chemical resistance due to the tetrafluoroethylene resin. Since the fluorinated ethynylene resin is given elasticity and reinforced by the elastic elastomer, it is possible to improve the sealing property, and the thickness of the expensive tetrafluoroethylene resin layer can be made thin, resulting in expected cost reduction. I can.

Also, since the lining layer can be molded using a mold,
Molding is easy and it is possible to reduce the manufacturing cost, and the position of the mold is set in the diametrical direction by the flange part that is inserted into the valve body, and the axial position is set by the use of a jig. As a result of being able to set accurately on the valve body, the lining layer to be formed has extremely high dimensional accuracy and it is possible to manufacture high quality products.

(Effect of the Invention) According to the present invention, since the valve body is formed of the hollow cylindrical metal pipe body such as the steel pipe, the manufacturing is simple and the cost can be reduced, and the valve body has the same diameter as the piping pipe. Therefore, the connection with the piping pipe can be performed by a simple connecting means such as a fastening band or a joint.

Since the lining layer that constitutes the seat ring of the valve body is composed of a tetrafluoroethylene resin layer and an elastic elastomer layer, it has high chemical resistance, high touch resistance, good sealing properties and sufficient strength. It becomes possible to cope with an extremely wide range of use conditions.

Further, since the lining layer is formed by using a mold that is accurately set according to the outer diameter of the valve body and the position of the shaft hole, it is possible to provide a high quality product with high dimensional accuracy.

[Brief description of drawings]

1 is a partially cutaway perspective view, FIG. 2 is a longitudinal sectional view,
3 is a front view of the valve body and valve stem guide, and FIG. 4 is FIG.
Fig. 5 is a vertical sectional view taken along the line IV-IV, Fig. 5 is an external perspective view showing a set state of the mold, Fig. 6 is an exploded perspective view, Fig. 7 is a vertical sectional view in the set state, and Fig. 8 is not shown. FIG. 9 is a longitudinal sectional view showing an injection state of vulcanized rubber, FIG. 9 is a perspective view showing an injection path,
The drawing is a partially enlarged cross-sectional view showing an exhaust state. (1) …… Valve body, (2) …… Shaft hole (3) …… Valve rod guide, (4) …… Valve rod guide (5) …… Lined layer (6) …… Tetrafluoride ethylene resin layer (7) …… Elastic elastomer layer (8) …… Valve seat, (9) …… Valve body (10) (11) …… Valve rod, (12) …… Lid body (13) …… First gold Mold, (14) …… second mold (15) …… injection mold, (16) …… valve seat molding part (17) …… cylindrical part, (18) …… groove part (19) …… Flange, (20) …… Jig insertion hole (21) …… Cylinder, (22) …… Groove (23) …… Flange, (24) …… Injection hole (25) …… Injection port, ( 26) …… Injection passage (27) …… Jig (28) …… Tetrafluoroethylene resin sheet molding (29) …… Cylindrical part, (30) …… Valve seat corresponding part (31) …… Flange part , (32) …… Opening (33) …… Ring

Claims (2)

[Claims] 1. A valve main body made of a hollow cylindrical metal tube having a predetermined length in the axial direction, a lining layer covering an inner peripheral surface and an end surface of the valve main body, and a shaft rotatably supported in the valve main body. A valve body having a disc-shaped valve body formed therein, and a valve body having a shaft hole opened in a central portion of the valve body so as to face in a diametrical direction, and a valve rod guide fixedly connected to the opening. The valve stem supporting the shaft is inserted into the valve stem guide, and one valve stem extends outward from the valve stem guide for connecting with the drive means, and the other valve stem terminates in the valve stem guide and the lining layer is A butterfly valve having a valve seat extending in the circumferential direction and having an outer peripheral edge of the valve body coming into contact with and separating from the central portion thereof, and formed of a tetrafluoroethylene resin layer and an elastic elastomer layer. 2. A tetrafluoroethylene resin sheet molded product, which is molded in a shape substantially corresponding to the inner surface shape of the lining layer, is inserted and set in a mold, and then the outer shape and the axial hole are formed in the mold and the valve body. In order to manufacture the butterfly valve according to item 1, the position is set and set by a jig to be inserted, and unvulcanized rubber is injected and vulcanized to form a lining layer. the method of.