JP3089211B2 - Center type butterfly valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can improve the shaft sealing performance of a valve shaft portion of a central butterfly valve having a valve body whose entire outer peripheral surface is coated with a resin, particularly a butterfly valve having a valve body coated with a resin. Also, the present invention relates to a center type butterfly valve capable of reducing valve opening / closing torque.

[0002]

2. Description of the Related Art Conventionally, a center type butterfly valve having a valve body coated with a resin having excellent corrosion resistance and chemical resistance is known, and is disclosed in, for example, Japanese Utility Model Laid-Open No. 51-98836. Fluororesin and the like are used as the corrosion-resistant and chemical-resistant resin currently used for coating the valve body. Cracks may be broken at the outer peripheral edge of the metal core. In addition, there is a possibility that the coating resin may be peeled off from the cored bar due to long-term use to cause crack breakage. Furthermore, since the core metal is usually a cast product, the weight of the valve body increases, and there is a risk of fluid leakage from the upper part of the valve body in the axial direction (gland direction) after assembly.

[0003] The use of a split valve body for a butterfly valve is disclosed in Japanese Utility Model Publication No. 2-29325. However, the valve element disclosed in this publication is a metal cast product or an FRP product, and the thickness of the valve element cannot be reduced from the viewpoint of strength or molding. However, there is a disadvantage that the pressure loss becomes large.

Japanese Unexamined Utility Model Publication No. 60-101267 discloses a valve core for joining two members formed of sheet metal, but the two members constituting the core are joined by rivets. Since the opening is provided in the valve body in order to fuse the front and back of corrosion-resistant and chemical-resistant resin, the number of work steps is large,
The cost has increased.

[0005] When the entire surface of the valve body is coated with a corrosion-resistant or chemical-resistant resin, a method of connecting the valve body and the valve rod through a tapered bolt or the like from the viewpoint of avoiding destruction due to stress concentration on the coating resin. Can not be adopted. In view of this, the valve stem has a vertically divided or penetrated structure, and a non-circular portion is provided on the valve stem and the valve body to integrate rotation. However, when the valve stem is divided into two parts or has a through-hole structure, a hole for inserting the valve stem into the core must be formed. Since the total thickness of the subsequent valve element also increases, it causes pressure loss.

[0006] The seal of the butterfly valve is formed by a seal between the valve body and the seat ring (primary seal), a seal between the seat ring and the valve stem (secondary seal), and a seal at the valve shaft (gland seal). It consists of. Normally, the primary seal satisfies the specified conditions such as pressure, temperature, fluid, etc.However, if the primary seal is incomplete due to long-term use, high frequency use, or biting of solids, etc. Department. The secondary seal due to the contact between the seat ring and the valve stem
The seal is improved by tightening the valve stem with a seat ring. Although the sealing performance is improved as the tightening force is increased, the valve opening / closing torque is increased, and the performance and function of the valve are impaired. Generally, the sealing performance is to be maintained by deforming the valve stem hole shape of the seat ring or making the valve stem hole diameter smaller than the valve stem diameter, but the contact surface of the valve stem becomes large and wear is reduced. Is the cause. In addition, the movement of the fluid to leak in the direction of the ground also acts as the valve stem rotates.

When the valve is closed, the valve is slightly moved to the secondary side by the total pressure (surface pressure) applied to the valve. Normally, the valve stem insertion hole of the valve body is formed slightly larger than the diameter of the valve stem, and a gap is provided between the valve stem and the valve stem to absorb machining errors (eccentricity) of the valve body, the valve body, the seat ring, and the like. Prevents sticking of sticks. For this reason, due to the surface pressure applied to the valve body, the valve stem moves to the secondary side by the amount of the gap, the valve shaft hole of the seat ring also deforms to an elliptical shape, and fluid leaks from the gap toward the gland. Will do.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent cracking of a coating resin layer, to reduce the pressure loss by forming a thin valve body, to facilitate processing work, and to reduce costs. It is an object of the present invention to provide a center type butterfly valve capable of reducing the weight of the valve body and preventing leakage of fluid in the direction of the gland.

[0009]

Means taken by the present invention to solve the above-mentioned problems is to provide a valve body in which the entire outer surface of a metal core is covered with a resin layer, which is pivotally supported on a valve body by a valve rod. The bearing cylinder is fixedly inserted into the valve barrel of the main body, the shaft sealing gasket is inserted into the rotating part between the bearing barrel and the valve body, and the bearing barrel, the seat ring and the valve barrel are in a non-rotation state. And a fixed packing is arranged at the non-rotating contact portion.
The diameter in the direction perpendicular to the valve stem is smaller than the diameter of the valve body.
It is formed in a small size and non-circular shape, and the inner end of the bushing is
The axial movement of the valve body is brought into surface contact with the metal
Characterized in that it can be performed via

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below. A butterfly valve according to the present invention comprises a hollow cylindrical valve body (1) made of a rigid material having a cylindrical flow path (2) and a valve body (1) as conventionally known.
A seat ring (3) made of an elastic material fitted on the entire inner peripheral surface of the flow path (2), and a disc-shaped valve (4) for opening and closing the flow path (2). The valve body (4) is a valve stem (5) of the valve body (1).
(6) is provided with valve rods (7) and (8) rotatably supported by a shaft, and is driven and rotated from the outside. The upper valve stem (7) is a drive-side valve stem, is connected to the valve body (4) by detent means, extends outward from the valve stem (5), and is appropriately connected to the outer end. Are mounted. The lower valve stem (8) is a floating valve stem, which is movably connected to the valve element (4), and is provided with a lower valve stem (6) for pivotally supporting the floating valve stem (8). The stem hole is closed with a plug (9).

Referring to FIGS. 2 to 5, the valve element (4) is provided with a metal core (1).
0) and a coating resin layer (11) covering the entire outer surface of the core metal (10), and the coating resin layer (11) is integrated with the core metal (10). The core bar (10) is a member formed by spot welding two molded products obtained by press-forming a rigid material, for example, a plate-shaped steel plate, and joining them together. The valve stems (7) and (8) are located at diametrically opposed positions. The valve stem insertion holes (12) and (13) are formed for mounting the valve stem. One valve stem insertion hole (12) is formed in a non-circular cross section such as a square, and is configured to rotate integrally with the driving side valve stem, while the other valve stem insertion hole (13) has a circular cross section. And is rotatable relative to the floating valve stem. The stem insertion holes (12) and (13) are
0) does not penetrate in the diametric direction,
In the center of (4), a protruding portion serving as a fluid resistance is not formed.

The coating resin layer (11) imparts corrosion resistance and chemical resistance to the valve body. For example, resins such as polyphenylene sulfide (PPS), nylon (PA), and polytetrafluoroethylene (PTFE) are used. . Coating resin layer
The outer peripheral edge of (11) corresponds to the outer peripheral edge of the valve body (4), and since its outer diameter is extremely important, the outer surface of the cored bar (10) is usually lined using a vulcanizing mold or the like. Formed by To increase the bonding strength between the coating resin layer and the core metal and to prevent the occurrence of cracks due to shrinkage and aging of the coating resin layer, FIG.
As shown in (2), the outer diameter of the core metal (10) is formed to have a smaller diameter than the outer peripheral edge of the coating resin layer. That is, the valve stem insertion hole direction of the core metal (10) is formed to have a slightly smaller diameter than the coating resin layer (11), and the direction perpendicular to this direction is about half the outer diameter of the coating resin layer (11). It is formed in the diameter of. This allows
The portion of the coating resin layer (11) is increased, the fusion and integration of the coating resin layer is achieved, and the occurrence of cracks due to shrinkage and aging is suppressed.

As is well known in the art, a wafer-type butterfly valve is sandwiched between flanges at the end of a pipe pipe and tightened. Prevents leaks.
In order to prevent the primary pressure from leaking to the secondary side when the valve is closed, the outer diameter of the valve body (4) is made slightly larger than the inner diameter of the seat ring (3), and it is almost proportional to the dimensional difference between the two. The valve body is brought into close contact with the seat ring at the sealing pressure to prevent the fluid from leaking to the secondary side.

Next, the sealing mechanism of the drive side valve stem (7) in the direction of the ground (valve stem direction) will be described. Referring to FIGS. 1 and 6, the inner end formed in the non-circular cross section of the drive side valve stem (7) has the valve stem insertion hole (12) of the non-circular cross section of the cored bar (10) as described above.
The bearing tube (14) is fitted around the outer periphery of the valve stem extending outward from the metal core (10). The bearing tube (14) has its inner end in surface contact with the outer peripheral surface of the cored bar (10), and is inserted into the valve shaft tube (5) of the valve body (1) while being inserted into the valve shaft tube (5).
A fixed member that rotatably supports a valve rod (7) inserted therein, the cylindrical body being terminated at the outer end surface of
It is fixedly inserted into the valve stem (5). A flange (15) is formed at the outer end of the bearing cylinder, and the bearing cylinder (14) is connected to the valve stem cylinder (5).
And the inner end of the valve stem (14) is brought into surface contact with the cored bar (10), thereby preventing the valve body (4) from moving up and down. The bushing (14) is made of a resin material having required strength, rigidity and lubricity, for example, polyphenylene sulfide (P
(PS), nylon (PA), polytetrafluoroethylene (PTFE), or the like, and is preferably formed of the same resin as the resin coating layer.

[0015] A coating resin layer (11)
A shaft sealing gasket (16) for tightly sealing the inner surface of the shaft is wound. The shaft seal packing (16) is a secondary seal portion having a supplementary sealing function to the primary seal provided by the close contact between the coating resin layer (11) and the seat ring (3). Grease or other lubricant is applied to the groove for mounting the shaft seal packing (16) during valve assembly, and the shaft seal packing is rubbed against the inner surface of the coating resin layer (11) during rotation of the valve body.
(16) Wear is prevented. The rubbing range due to the rotation of the valve body (4) is only the area (a) where the coating resin layer (11) of the valve body comes into contact with the bearing cylinder (14), and the seat ring and the bearing cylinder rub against each other. Because it is a non-rotating part that does not
According to (16), the barrier for leakage in the ground direction is in a sealed state.

The bearing tube (14) is inserted and supported in the valve shaft tube (5), and is inserted and supported in the shaft hole (17) of the seat ring (3). The valve body (4) is prevented from moving to the secondary side by the surface pressure. Leakage in the direction of the ground is prevented by the contact between the seat ring and the bushing. The packings (18) and (19) mounted on the upper and lower sides of the bearing cylinder (14) contact the inner surfaces of the valve stem cylinder (5) and the seat ring (3) to perform the function of fixed packing. In addition, a shaft seal (20) is mounted on the outer peripheral surface of the valve stem close to the outer end of the bushing, and slidably rubs against the inner peripheral surface of the bushing as the valve stem rotates. It functions as a tertiary seal that seals the space between the cylinders and prevents infiltration of rainwater from the outside and prevents leakage of fluid from the inside.

In order to lubricate the rotation of the valve stem (7) and the bearing cylinder (14), a part of the valve stem is undercut to form a lubricating oil groove (2).
1) is formed, and the lubricant groove (21) is filled with a lubricant such as grease. An air gap (22) formed between the valve stem (5) and the bearing sleeve (14) is a machining relief.

The lower floating valve stem (8) is inserted into the lower valve stem cylinder (6) together with the lower bearing cylinder (23) from below, and a plug (9) is inserted.
The shaft seals (24) and (25) prevent the fluid from leaking to the outside. The upper end surface of the bearing tube (23) is in surface contact with the lower surface of the cored bar (10), so that the valve body (4) can be moved up and down by the up and down movement of the plug (9). I have.

[0019]

According to the present invention, the valve shaft orthogonal to the cored valve stem is provided.
The diameter dimension in the direction of
The core is made of sheet metal because it is formed in a circular shape.
It is possible to achieve a reduction width of Weight, Benbo挿
For the fusion of the front and back of the through section, the joint, the outer peripheral edge, and the coating resin layer
The machining of the opening of
The cost can be reduced and the cost can be reduced. or,
Reduce the thickness of the core metal and the total thickness of the valve body after resin coating
Can be reduced, and the flow area when the valve is fully open increases,
Prevents cavitation and protects the coating resin layer
can do. Furthermore, the inner end of the bearing cylinder is
Contact the surface to move the valve body in the axial direction through the bushing.
So that the weight of the valve body is supported by the bushing
The valve stem can be vertical or horizontal
However, regardless of this, the self-weight of the valve body can be reduced.
To prevent fluid leakage toward the ground
You.

[Brief description of the drawings]

FIG. 1 is an overall vertical sectional view.

FIG. 2 is a perspective view in which a part of a valve body is cut away.

FIG. 3 is a perspective view of a metal core.

FIG. 4 is a front view of a cored bar.

FIG. 5 is a longitudinal sectional view of a metal core.

FIG. 6 is an enlarged sectional view of FIG. 1A part;

[Explanation of symbols]

 (1) Valve body (2) Flow path (3) Seat ring (4) Valve (5) Valve stem (6) Valve stem (7) Driving valve stem (8) Idle valve stem (9) Plug (10) Core bar (11) Coated resin layer (12) Valve rod insertion hole (13) Valve rod insertion hole (14) Bearing cylinder (15) Flange (16) Shaft seal (17) Shaft hole (18) Fixed packing (19) Fixed packing (20) Shaft seal (21) Lubricating oil groove (22) Air gap (23) Lower bearing cylinder (24) Shaft seal (25) Shaft seal

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-1475 (JP, A) JP-A-6-245427 (JP, A) JP-A-60-101267 (JP, U) JP-A-62 188621 (JP, U) JP-A 4-25071 (JP, U) JP-B 7-81585 (JP, B2) JP-B 48-25707 (JP, Y2) JP-A 1-25815 (JP, Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16K 1/16-1/226

Claims (1)

(57) [Claims] 1. A valve body in which the entire outer surface of a cored bar is covered with a resin layer is supported on a valve body by a valve rod, and a bearing cylinder is fixedly inserted into a valve stem of the valve body. In a butterfly valve in which a shaft sealing gasket is inserted into a rotating portion of a valve body and a valve body, a bearing cylinder and a seat ring and a valve shaft cylinder are brought into contact with each other in a non-rotating state, and a fixed packing is arranged in the non-rotating contact portion . , Perpendicular to the core stem
The diameter dimension in the direction of
Formed into a circular shape, and the inner end of the bearing cylinder is interviewed with the core of the valve body
To move the valve body in the axial direction through the bushing.
A center type butterfly valve characterized by the following.