JPH0596641U - Butterfly valve - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the durability and chemical resistance of the valve by improving the sealing part to stop water only by metal touch. In a butterfly valve in which a valve body 2 having a diameter equal to a flow passage inner diameter is housed in a valve box 1 and the valve body 2 is rotated around a valve shaft 3 to open and close a flow of fluid, the valve body 2 The valve shaft 3 is provided with an elliptical portion 6 so that the shaft hole 5 of the valve box 1 is formed into an elliptical shape, and the elliptical portion 6 has an outer peripheral surface on the long diameter side and an inner peripheral surface on the short diameter side of the shaft hole 5. Is configured so that when the valve is closed, water can be stopped and water can be stopped.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a butterfly valve that opens and closes a flow of liquid, for example, a metal sheet butterfly valve for water supply.

[0002]

[Prior Art]

 A butterfly valve generally contains a disc-shaped valve element with the same diameter as the inner diameter of the flow passage in a cylindrical valve box, and the valve shaft of the valve element is rotated to open and close the fluid flow. It is structured to

FIG. 2 is a partial vertical cross-sectional view of a conventional concentric metal seat butterfly valve. In this figure, 11 is a valve box of a butterfly valve, and a valve box boss 12 is formed on the upper and lower parts of the valve box 11, and a valve shaft 14 of a valve body 13 is rotatably attached to the valve box boss 12. It is pivotally supported. In this conventional butterfly valve, a bush 15 is fitted in the end portion of the valve shaft 14, and the valve shaft 14 fitted in the bush 15 is inserted in the shaft hole 16 of the valve box boss 12.

In the butterfly valve, since it is necessary to insert the valve shaft 14 into the valve box 11, there is no choice but to provide the shaft hole 16 that penetrates the circular seat surface 17, and thus the conventional shaft hole 16 A rubber sealing material 18 was used for sealing to prevent water leakage from the valve shaft 14.

[0005]

[Problems to be solved by the device]

 However, in the above-mentioned conventional butterfly valve, since the sealing material 18 is made of rubber, even if it is a metal seat butterfly valve, the life of the sealing material 18 becomes the life of the butterfly valve, and there is a problem in durability. Moreover, the rubber seal material 18 has a drawback that it is weak against chemicals.

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

[0007]

[Means for Solving the Problems]

 The butterfly valve of the present invention is a butterfly valve in which a valve body having a diameter equal to the inner diameter of the flow passage is housed in a valve box, and the valve body is rotated around a valve axis to open and close the flow of fluid. The valve shaft is provided with an elliptical portion to form the shaft hole of the valve box into an elliptical shape. It is configured to be in close contact at times.

[0008]

[Action]

 With the above configuration, the inner peripheral surface on the minor axis side of the shaft hole of the valve box and the outer peripheral surface on the major axis side of the elliptical portion of the valve shaft are in close contact with each other when the valve is closed. The close contact between the inner peripheral surface of the shaft hole and the outer peripheral surface of the elliptical portion can prevent water leakage from the upstream side to the downstream side. For this reason, the rubber seal material that was required in the past is no longer necessary, and the durability and chemical resistance of the butterfly valve are improved.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an essential part of a sealing portion of a metal seat butterfly valve according to the present invention, in which 1 is a butterfly valve valve box, 2 is a valve body housed in the valve box 1, and 3 is a valve body. It is a valve shaft that rotates the valve body 2.

A valve box boss 4 is formed in the upper and lower parts 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. 2, and the minor axis of the ellipse is formed so as to be at right angles to the flow direction of the fluid.

A bearing 6 corresponding to an elliptical portion is externally fitted to the valve shaft 3 pivotally supported in 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 the upper portion of the valve body 2. As shown in FIG. 2, the bearing 6 has an elliptical cross section whose size is 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 circumference of the minor axis side of the axial hole 5 are closed. It is structured so that the surfaces are 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. In the copper packing 9, packing 9A for sealing the shaft diameter and packing 9B for sealing the hole diameter are fitted alternately.

Next, the operation of the above embodiment will be described. When the valve is open, the valve body 2 is open in the same direction as the fluid flow. At this time, as for the relationship between the bearing 6 and the shaft hole 5, the inner peripheral surface of the shaft hole 5 and the outer peripheral surface of the bearing 6 are not in contact with each other, as shown in FIG. Therefore, the fluid may leak to the downstream side through the gap between the shaft hole 5 and the bearing 6, but there is no problem because the fluid flows to the downstream side when the valve is opened. Water leakage from the gap 10 upward is blocked 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 in this valve closed state is that the inner peripheral surface on the minor axis side of the shaft hole 5 and the outer peripheral surface on the major diameter side of the bearing 6 are in close contact with each other as shown in FIG. There is. The close contact between the inner peripheral surface of the shaft hole 5 and the inner peripheral surface of the bearing 6 can prevent water leakage from the upstream side to the downstream side. In the past, machining error between the shaft hole and the valve shaft was easy, but 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 into an elliptical shape. By absorbing the machining error of the seat surface, it is possible to stop the leakage of water from the contact surface between the shaft hole 5 and the bearing 6.

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. However, in the present invention, the valve shaft 3 itself has an elliptical portion. It may be formed in.

[0016]

[Effect of the device]

 As described above, according to the present invention, by removing the rubber member from the sealing portion, the sealing portion can stop the water only by the metal touch, so that the durability and the chemical resistance are excellent.

[Brief description of 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 the line AA of FIG. 1, and FIG. 2B is a sectional view taken along the line AA of FIG. 1 when the valve is open.

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

FIG. 4 is a partial vertical cross-sectional view of a conventional concentric metal seat butterfly valve.

[Explanation of symbols]

 1 valve box 2 valve body 3 valve shaft 4 valve box boss 5 valve hole 6 bearing (oval part)

Claims (1)

[Scope of utility model registration request] 1. A butterfly valve, wherein a valve body having a diameter equal to a flow passage inner diameter 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 box to form the shaft hole of the valve box into an elliptical shape, and the outer peripheral surface on the major axis side of the elliptical portion of the valve shaft and the inner peripheral surface on the minor diameter side of the shaft hole are in close contact when the valve is closed. A butterfly valve characterized by being configured as described above.