JPH09303575A - Center type butterfly valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of a fluid along the direction of a gland by fitting a shaft seal packing to the turning part of a bearing cylinder and a valve, keeping the bearing cylinder, a seat ring and a valve spindle cylinder in contact with one another in a non-turning state and providing a fixed packing at the non-turning contact part. SOLUTION: A bearing cylinder 14 is coupled to the external surface of a stem 7 extended outside from a mandrel 10, thereby rotatably supporting the stem 7. A shaft seal packing 16 is fitted to the non-turning part where a seat ring 3 and a bearing cylinder does not slidably contact, at a position deep inside the bearing cylinder 14, thereby closing a passage in the direction of a gland. The bearing cylinder 14 is coupled to and supported on a stem cylinder 5 and at the same time, inserted in and supported on the shaft hole 17 of the seat ring 3. The travel of a valve 4 toward a secondary side is thereby prevented at a valve closing process. Also, leakage in the direction of the gland is prevented via contact between the seat ring 3 and the bearing cylinder 14. Furthermore, packings 18 and 19 attached to the upper and the lower sides of the bearing cylinder 14 are kept in contact with the internal surfaces of the stem cylinder 5 and the seat ring 3, thereby functioning as fixed packings.

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 resin, and particularly a butterfly valve having a valve body coated with resin. At the same time, it relates to a central butterfly valve capable of reducing the valve opening / closing torque.

[0002]

2. Description of the Related Art Conventionally, a central butterfly valve having a valve body coated with a resin having excellent corrosion resistance and chemical resistance has been known, and is disclosed in, for example, Japanese Utility Model Publication No. 51-98836. Fluororesin is used as a resin with corrosion resistance and chemical resistance that is currently used for coating valve bodies, but since such resin undergoes large shrinkage during coating and molding, There was a risk of crack breakage at the outer peripheral edge of the cored bar. In addition, there is a possibility that the coating resin may be peeled off from the core metal to cause crack breakage after long-term use. Further, since the core metal is usually a cast product, the weight of the valve body is large, and there is a risk of fluid leakage from the upper part of the valve body in the axial direction (ground direction) after assembly.

The use of a split type valve body for the butterfly valve is disclosed in Japanese Utility Model Publication No. 2-29325. However, the valve element disclosed in this publication is a metal casting product or an FRP product, and the thickness of the valve element cannot be reduced from the viewpoint of strength or molding, so that the total thickness of the valve element becomes large and the valve is fully opened. There was a drawback that the pressure loss of was large.

Japanese Utility Model Laid-Open No. 60-101267 discloses a core metal of a valve body which joins two sheet-metal molded members. The two members constituting the core metal are joined by rivets. Since the opening is provided in the valve body in order to combine the front and back of corrosion-resistant and chemical-resistant resin, the number of work steps is large,
The cost has increased.

When the entire surface of the valve body is coated with a resin having corrosion resistance and chemical resistance, a method of connecting the valve body and the valve rod by penetrating a taper bolt or the like from the viewpoint of avoiding damage due to stress concentration on the coating resin. It cannot be adopted. Therefore, the valve rod is divided into upper and lower halves or has a penetrating structure, and the valve rod and the valve body are provided with non-circular diameter portions to integrate the rotation. However, when the valve rod is divided into two or has a through structure, a hole for inserting the valve rod must be formed in the core metal, and the core metal of the cast product has a large wall thickness of the core metal itself and is coated with resin. Since the total thickness of the valve body afterward becomes large, it causes pressure loss.

The seal of the butterfly valve is a seal (primary seal) by contact between the valve body and the seat ring, a seal (secondary seal) by contact between the seat ring and the valve rod, and a seal (ground seal) at the valve shaft portion. It is composed by. Normally, the primary seal satisfies the specified conditions of pressure, temperature, fluid, etc., but if the primary seal becomes incomplete due to long-term use, high-frequency use, or the entrapment of solid matter, etc., the fluid will become a secondary seal. Will reach the department. The secondary seal due to the contact between the seat ring and the valve rod is
By tightening the valve rod with a seat ring, the sealability is improved. Although the sealing performance improves as the tightening force increases, the valve opening / closing torque increases and the performance and function of the valve are impaired. Generally, it is attempted to maintain the sealing performance by deforming the valve shaft hole shape of the seat ring or by making the valve shaft hole diameter smaller than the valve shaft diameter, but the contact surface of the valve shaft becomes large and wear occurs. Is the cause. Further, with the rotation of the valve rod, the fluid also tends to leak toward the ground.

When the valve is closed, the valve body is slightly moved to the secondary side by the total pressure (surface pressure) applied to the valve body. Normally, the valve stem insertion hole of the valve body is formed slightly larger than the valve stem diameter, and a gap is provided between the valve stem and the valve stem to absorb processing errors (eccentricity) in the valve body, valve body, seat ring, etc. Prevents stick sticking. Therefore, due to the surface pressure applied to the valve body, the valve rod moves to the secondary side by this gap, the valve shaft hole of the seat ring is also deformed into an elliptical shape, and fluid leaks from the gap toward the ground. Will be done.

[0008]

SUMMARY OF THE INVENTION According to the present invention, it is possible to prevent cracking of a coating resin layer, form a thin valve element to reduce pressure loss, facilitate a working operation, and reduce cost. It is intended to provide a central butterfly valve which is capable of reducing the weight of the valve element and preventing fluid leakage in the gland direction.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, the means adopted by the present invention is such that a valve body in which the entire outer surface of a core metal is covered with a resin layer is pivotally supported on a valve body by a valve rod. In a central butterfly valve, a bearing cylinder is fixedly inserted in a valve shaft cylinder of a valve body, a valve rod is rotatably supported on the bearing cylinder, and a rotating portion between the bearing cylinder and the valve body is provided. Insert the shaft seal packing,
The bearing cylinder, the seat ring, and the valve shaft cylinder are brought into contact with each other in a non-rotating state, and a fixed packing is arranged at the non-rotating contact portion.

Further, the core metal is made of a plurality of members which are formed by sheet metal and integrally joined, and the diameter of the core in the direction orthogonal to the valve rod is formed to be smaller than the diameter of the valve body to have a non-circular shape. Is characterized by.

Further, a feature is that a part of the valve rod is recessed to form a gap between the valve rod and the bearing cylinder to form a lubricant groove for filling with a lubricant.

Further, the present invention is characterized in that the inner end of the bearing cylinder is brought into surface contact with the core metal of the valve body so that the valve body can be moved in the axial direction through the bearing cylinder.

[0013]

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.
The seat ring (3) made of an elastic material fitted to the entire inner peripheral surface of the channel (2) and the disc-shaped valve body (4) for opening and closing the channel (2). The valve body (4) is the valve stem (5) of the valve body (1).
A valve rod (7) and (8) rotatably supported on (6) is provided and driven and rotated from the outside. The upper valve rod (7) is a valve rod on the driving side, is connected to the valve body (4) by a rotation stopping means, extends outward from the valve shaft cylinder (5), and is appropriately attached to the outer end. The actuator of is attached. The lower valve rod (8) is a floating valve rod, which is movably connected to the valve body (4) and is of a lower valve stem (6) that pivotally supports the floating valve rod (8). The valve shaft hole is closed with a plug (9).

Referring to FIGS. 2 to 5, the valve body (4) has a core metal (1
0) and a coating resin layer (11) that covers the entire outer surface of the core metal (10), and the coating resin layer (11) is integrated with the core metal (10). The core metal (10) is a member formed by spot-welding two molded products obtained by press-molding a rigid material, for example, a plate-shaped steel plate, and integrally joining them. The valve rods (7) (8) are located at diametrically opposite positions. Valve stem insertion holes (12) (13) for mounting the valve are formed. One valve rod insertion hole (12) is formed in a non-circular cross section such as a square, and is designed to rotate integrally with the drive side valve rod, while the other valve rod insertion hole (13) has a circular cross section. Is formed on the movable side valve rod and is rotatable relative to the floating side valve rod. The valve rod insertion holes (12) (13) are
(0) does not penetrate diametrically and is terminated midway
In the central portion of (4), a protruding portion which becomes a fluid resistance is not formed.

The coating resin layer (11) imparts corrosion resistance and chemical resistance to the valve body, and for example, a resin such as polyphenylene sulfide (PPS), nylon (PA), polytetrafluoroethylene (PTFE) is used. . Coating resin layer
The outer peripheral edge of (11) corresponds to the outer peripheral edge of the valve body (4), and since the outer diameter dimension thereof is extremely important, the outer surface of the core metal (10) is usually lined with a vulcanizing mold or the like. Is formed by. In order to increase the bonding strength between the coating resin layer and the core metal and prevent the occurrence of cracks due to shrinkage or aging of the coating resin layer,
As shown in, the outer diameter of the core metal (10) is formed to have a smaller deformation than the outer peripheral edge of the coating resin layer. That is, the valve rod insertion hole direction of the core metal (10) is formed to have a slightly smaller diameter dimension than the coating resin layer (11), and the direction orthogonal to this is about half the outer diameter dimension of the coating resin layer (11). Is formed to have a diameter of. This allows
The number of portions of the coating resin layer (11) is increased, the coating resin layers are integrated and integrated, and the generation of cracks due to shrinkage or aging is suppressed.

As is well known in the art, the wafer type butterfly valve is clamped by clamping it between the end flanges of the piping pipe, and a seat ring (3) slightly protruding from the valve body is brought into close contact with the flange so that the fluid from this portion is removed. Prevents leakage.
Also, the outside diameter of the valve body (4) is made slightly larger than the inside diameter of the seat ring (3) so that the pressure on the primary side does not leak to the secondary side when the valve is closed. The valve body is brought into close contact with the seat ring by the sealing pressure to prevent the fluid from leaking to the secondary side.

Next, the seal mechanism of the drive side valve rod (7) in the gland direction (valve rod direction) will be described. Referring to FIGS. 1 and 6, the inner end of the drive side valve rod (7) formed in the non-circular cross section has the non-circular cross section valve rod insertion hole (12) of the core metal (10) as described above.
The bearing cylinder (14) is fitted around the outer circumference of the valve rod extending outward from the core metal (10). The bearing cylinder (14) has its inner end in surface contact with the outer peripheral surface of the cored bar (10) and is fitted into the valve shaft cylinder (5) of the valve body (1) while being inserted into the valve shaft cylinder (5).
Is a tubular member terminating at the outer end surface of the, and is a fixed member that pivotally supports the valve rod (7) inserted inside,
It is fixedly inserted in the valve stem (5). A flange (15) is formed on the outer end of the bearing cylinder, and the bearing cylinder (14) is connected to the valve shaft cylinder (5).
The vertical movement of the valve body (4) is prevented by positioning the valve body (4) and making the inner end of the valve shaft cylinder (14) in surface contact with the core metal (10). The bearing tube (14) is made of a resin material having required strength, rigidity and lubricity, such as polyphenylene sulfide (P).
It is preferable to use the same resin as the resin coating layer such as PS), nylon (PA), and polytetrafluoroethylene (PTFE).

A coating resin layer (11) is formed on the inner rear portion of the bearing tube (14).
A shaft seal packing (16) that tightly adheres to and seals the inner surface of the 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). A lubricant such as grease is applied to the groove where the shaft seal packing (16) is installed when the valve is assembled, and the shaft seal packing is rubbed against the inner surface of the coating resin layer (11) when the valve body rotates.
(16) wear is prevented. The sliding range due to the rotation of the valve body (4) is only the range (a) where the coating resin layer (11) of the valve body and the bearing cylinder (14) are in contact with each other, and the seat ring and the bearing cylinder are rubbed with each other. Since it is a non-rotating part that does not
Due to (16), the leakage barrier in the ground direction is sealed.

The bearing cylinder (14) is fitted and supported by the valve shaft cylinder (5) and is also fitted and rotatably supported by the shaft hole (17) of the seat ring (3). The surface pressure prevents the valve body (4) from moving to the secondary side. The contact between the seat ring and the bearing sleeve prevents leakage in the gland direction. The packings (18) and (19) mounted on the upper and lower sides of the bearing cylinder (14) are in contact with the inner surfaces of the valve shaft cylinder (5) and the seat ring (3) to serve as fixed packings. Further, a shaft seal packing (20) is attached to the outer peripheral surface of the valve rod in the vicinity of the outer end of the bearing cylinder, and the valve rod and the bearing are rubbed with the inner peripheral surface of the bearing cylinder as the valve rod rotates. The space between the cylinder and the cylinder is sealed to prevent the intrusion of rainwater from the outside and to act as a tertiary seal for preventing the leakage of fluid from the inside.

In order to lubricate the rotation of the valve rod (7) and the bearing sleeve (14), a part of the valve rod is undercut and the lubricating oil groove (2
1) is formed, and the lubricating oil groove (21) is filled with a lubricant such as grease. The space (22) formed between the valve shaft cylinder (5) and the bearing cylinder (14) is a working relief.

The lower floating valve rod (8) is fitted into the lower valve shaft cylinder (6) together with the lower bearing cylinder (23) from below, and the plug (9).
Thus, the shaft is sealed, and the shaft sealing packings (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), and the vertical movement of the plug (9) enables the vertical movement of the valve body (4). There is.

[0022]

According to the present invention, the valve rod is rotatably supported by the bearing cylinder fitted and inserted in the valve body, and the bearing cylinder is fitted and supported by the valve shaft cylinder and the seat ring. The valve body is prevented from being moved to the secondary side by the surface pressure applied to the valve body when the valve is closed, and the fluid leakage in the ground direction is prevented. Further, since the rotation of the valve rod during opening and closing of the valve is performed within the bearing cylinder and is only slightly in contact with the valve body at the portion of the coating resin layer and the bearing cylinder, it is accompanied by the rotation of the valve rod. There are few worn parts and the turning torque is reduced.

Further, since the weight of the valve element is supported by the bearing tube, the weight of the valve element can be reduced regardless of the vertical or horizontal direction of the valve rod, and fluid leakage in the gland direction can be prevented. You can

The cored bar is made of sheet metal and can be formed into any shape for joining with the valve body.
It is possible to achieve a significant reduction in weight and eliminates the need for mechanical processing such as the valve rod insertion part, the joint part, the outer peripheral edge part, and the opening for fusion of the front and back sides of the coating resin layer, which greatly reduces the number of processing steps. It is possible to reduce the production cost. Further, the core metal can reduce the thickness thereof to reduce the total thickness of the valve body after resin coating, the flow-through area becomes large when the valve is fully opened, and it prevents cavitation and the like and protects the coating resin layer. You can

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view

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

FIG. 3 is a perspective view of a cored bar

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

FIG. 5 is a vertical sectional view of a cored bar.

FIG. 6 is an enlarged sectional view of a portion of FIG. 1A.

[Explanation of symbols]

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

Claims (4)

[Claims] 1. A center type butterfly valve comprising a valve body having a core metal covered on its entire outer surface with a resin layer and pivotally supported on the valve body by a valve rod, in which a bearing cylinder is fixed in a valve shaft cylinder of the valve body. And the valve rod is rotatably supported on the bearing cylinder, and a shaft seal packing is inserted in the rotating portion between the bearing cylinder and the valve body to separate the bearing cylinder, the seat ring and the valve shaft cylinder from each other. A central butterfly valve, wherein a contact is made in a rotating state, and a fixed packing is arranged at the non-rotating contact portion. 2. The cored bar is composed of a plurality of members formed by sheet metal forming and joined together, and has a non-circular shape in which the diameter dimension in the direction orthogonal to the valve rod is smaller than the diameter of the valve body. The butterfly valve according to claim 1, wherein: 3. A butterfly valve according to claim 1, wherein a part of the valve rod is provided as a recess to form a gap between the valve stem and the bearing cylinder, and the groove serves as a lubricant groove. 4. The bearing cylinder according to claim 1, wherein the inner end of the bearing cylinder is brought into surface contact with the core metal of the valve disc so that the axial movement of the valve disc can be performed via the bearing cylinder. Butterfly valve.