JP2572592Y2 - Butterfly valve - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve for opening and closing a flow of a liquid, for example, a metal sheet butterfly valve for water supply.

[0002]

2. Description of the Related Art In general, a butterfly valve accommodates a disc-shaped valve element having the same diameter as the inner diameter of a flow path in a cylindrical valve box, and rotates the valve shaft of the valve element. It has a structure that opens and closes the flow of fluid.

FIG. 2 is a partial longitudinal sectional view of a conventional concentric metal seat butterfly valve. In this figure, reference numeral 11 denotes a valve box of a butterfly valve, and a valve box boss 12 is formed at an upper portion and a lower portion of the valve box 11, and a valve shaft 14 of a valve body 13 is rotatable on the valve box boss 12. It is pivoted. In this conventional butterfly valve, a bush 15 is fitted to the end of the valve shaft 14, and the valve shaft 14 fitted with the bush 15 is inserted into a shaft hole 16 of the valve box boss 12.

The butterfly valve has to be provided with a shaft hole 16 penetrating a circular seat surface 17 because the valve shaft 14 must be inserted into the valve box 11.
The rubber seal member 18 is used for sealing for preventing water leakage between the valve shaft 14 and the valve shaft 14.

[0005]

However, in the above-mentioned conventional butterfly valve, since the seal member 18 is made of rubber, the life of the seal member 18 becomes the life of the butterfly valve even though it is a metal sheet butterfly valve. There was a problem in durability. In addition, the rubber sealing material 18 has a disadvantage that it is weak against chemicals.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and has improved the durability and chemical resistance of a valve by improving a sealing portion so that water can be stopped only by a metal touch. The purpose of the present invention is to provide a butterfly valve.

[0007]

In the butterfly valve of the present invention, a valve body having a diameter equal to the inner diameter of the flow path is housed in a valve box, and the valve body is rotated around a valve axis to flow the fluid. In a butterfly valve that opens and closes, an elliptical portion is provided on a valve shaft of a valve body, a shape of a shaft hole of a valve box is formed in an elliptical shape, and an outer peripheral surface on a longer diameter side of the valve shaft and a shorter diameter side of the shaft hole. Is configured to be in close contact with the inner peripheral surface when the valve is closed.

[0008]

According to the above-described structure, the inner peripheral surface on the shorter diameter side of the shaft hole of the valve box and the outer peripheral surface on the longer diameter side of the elliptical portion of the valve shaft are in close contact with each other when the valve is closed. By the close contact between the inner peripheral surface of the shaft hole and the outer peripheral surface of the elliptical portion, water leakage from the upstream side to the downstream side can be stopped. For this reason, the rubber sealing material conventionally required is not required at all, and the durability and chemical resistance of the butterfly valve are improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part of a sealing portion of the metal seat butterfly valve of the present invention.
Is a valve box of a butterfly valve, 2 is a valve element housed in the valve box 1, and 3 is a valve shaft for rotating the valve element 2.

A valve box boss 4 is formed in the upper and lower portions of the valve box 1, and a shaft hole 5 is formed in the valve box boss 4. The cross section of the shaft hole 5 is elliptical as shown in FIG.
The minor axis of the ellipse is formed so as to be perpendicular to the direction in which the fluid flows.

A bearing 6 corresponding to an elliptical portion is externally fitted to the valve shaft 3 supported by the shaft hole 5, and the bearing 6 is integrally fixed to the valve shaft 3. The lower end of the bearing 6 is formed in a tapered shape, and is inserted and fixed in a tapered hole 7 formed in an upper portion of the valve body 2. As shown in FIG. 2, the bearing 6 has an elliptical cross section slightly smaller than the elliptical shape of the shaft hole 5. The major axis of the elliptical bearing 6 and the minor axis of the elliptical shaft hole 5 are the same, and when the valve is closed, the outer peripheral surface of the major axis side of the bearing 6 and the inner periphery of the minor axis side of the shaft hole 5 when the valve is closed. The surfaces are configured to be in close contact.

A flange 8 is fitted in the upper part of the shaft hole 5. A copper packing 9 as shown in FIG. 3 is fitted between the flange 8 and the bearing 6 to stop water leakage to the upper part. Copper packing 9 is a packing 9A that seals the shaft diameter.
And a packing 9B for sealing the hole diameter are alternately fitted.

Next, the operation of the above embodiment will be described. When the valve is opened, the valve body 2 is opened in the same direction as the flow of the fluid. At this time, the relationship between the bearing 6 and the shaft hole 5 is such that the inner peripheral surface of the shaft hole 5 does not contact the outer peripheral surface of the bearing 6 as shown in FIG.
Is slightly open. Therefore, there is a possibility that the fluid leaks downstream from the gap between the shaft hole 5 and the bearing 6, but there is no problem because the fluid flows downstream when the valve is opened. The gap 10
Leakage upward from is prevented by the copper packing.

When the valve is closed, the valve shaft 3 is rotated by 90 degrees so that the valve body 2 is at a right angle to the fluid. The relationship between the bearing 6 and the shaft hole 5 when the valve is in the closed state is such that the inner peripheral surface on the shorter diameter side of the shaft hole 5 and the outer peripheral surface on the longer diameter side of the bearing 6 are in close contact as shown in FIG. I have. Due to the close contact between the inner peripheral surface of the shaft hole 5 and the inner peripheral surface of the bearing 6, water leakage from the upstream side to the downstream side can be stopped. Conventionally, a machining error between the shaft hole and the valve shaft is easily caused. In the present invention, the shaft hole 5, the shaft diameter, and the valve body are formed by forming the shaft hole 5 and the bearing 6 in an elliptical shape. Processing errors in the seat surface can be absorbed, and water leakage from the contact surface between the shaft hole 5 and the bearing 6 can be stopped.

In the above embodiment, the bearing 6 is formed in an elliptical shape, and the bearing 6 is externally fitted and fixed to the valve shaft 3 to form an elliptical portion. In the present invention, the valve shaft 3 itself has an elliptical portion. May be formed.

[0016]

As described above, according to the present invention, since the rubber member is removed from the sealing portion by the above-described structure, the sealing portion can be stopped with only metal touch, so that it has excellent durability and chemical resistance. I have.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of a butterfly valve according to an embodiment of the present invention.

2A is a sectional view taken along line AA of FIG. 1, and FIG. 2B is a sectional view taken along line AA of FIG. 1 when the valve is opened.

FIG. 3 is an enlarged view of a portion X in FIG. 1;

FIG. 4 is a partial longitudinal sectional view of a conventional concentric metal seat butterfly valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve box 2 Valve body 3 Valve shaft 4 Valve box boss 5 Valve hole 6 Bearing (elliptical part)

Claims (1)

(57) [Scope of request for utility model registration] 1. A butterfly valve in which a valve body having a diameter equal to the inner diameter of a flow path is housed in a valve box, and the valve body is rotated around a valve axis to open and close a flow of fluid. An elliptical portion is provided on the valve body, and the shape of the shaft hole of the valve box is formed in an elliptical shape, and the outer peripheral surface on the longer diameter side of the elliptical portion of the valve shaft and the inner peripheral surface on the shorter diameter side of the shaft hole are in close contact with each other when the valve is closed. A butterfly valve having the above-mentioned structure.