JPS6124766Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a butterfly valve.

Generally, butterfly valves are configured so that when the valve is closed, the periphery of the valve body is pressed against a seat ring attached to the inner surface of the valve body.

Conventionally, the seal structure between the valve body and the seat ring in a butterfly valve is shown in Figs. 7 and 8.
The one shown in the figure exists. The one in Figure 7 has a structure in which the valve body 3 bites into the inner circumferential surface of the seat ring 2 to close it, so that the valve body 3 engages with the seat ring 2 in front of the closed position, as shown by the dashed line. contact,
The distance S to the closed position digs into the inner surface of the seat ring 2, and undesirable force acts on the seat ring 2 every time it is opened or closed, which not only increases the rotational torque of the valve body 3 but also causes damage to the seat ring. There is. In addition, in view of this difficulty, as in Utility Model Publication No. 52-30600 shown in FIG. Some models employ a structure in which the valve body 3 is pressed against the top of the middle high part 12 to close it, but the sealing pressure in the closed state is such that the valve body 3
The disadvantage is that only a certain value can be obtained at the location where the pressure is applied.

Therefore, the purpose of this invention is to prevent the valve body from digging into the inner surface of the seat ring as in the past, to prevent undesirable forces from acting on the seat ring each time it is opened and closed, and to prevent the rotation torque of the valve body from becoming large. In addition to not causing damage to the seat ring, it is possible to increase the sealing pressure and provide good sealing performance.Furthermore, the sealing pressure can be adjusted as appropriate, resulting in stable closure over a long period of time. We are trying to provide a butterfly valve that is effective.

In order to achieve the above object, this invention forms a tapered part on the peripheral edge of the valve body, and on the inner surface of the seat ring, excluding at least the above-mentioned shaft hole forming part, the inner surface of the seat ring is formed at the front and back positions of the valve body when it is fully closed. A configuration is adopted in which a raised portion is provided, and an inclined portion is formed on the side edge of the raised portion to which the tapered portion of the valve body is pressed, and the inclined portion is used as a pressure sealing surface against which the front and back peripheral edges of the valve body are pressed.

Therefore, when the valve body is closed, the tapered portion of the peripheral edge of the valve body presses and seals against the inclined part of the inward protrusion according to the rotational force of the valve body, and the rotational force of the valve body is adjusted. As a result, the sealing pressure can be further increased and controlled. In other words, even after the tapered portion of the valve body is in pressure contact with the inclined portion from the side, if the rotational force of the valve body is further increased, the valve body with one side fixed in position by the valve shaft will exert a wedge effect on the tapered portion. As a result, the sealing pressure gradually increases and pressure contact is established, making the sealing state even more reliable. However, on the other hand, the sealing pressure directly depends on the rotational force of the valve body and can be controlled appropriately according to the slope shape.
Unlike conventional valves, it does not dig into the inner surface of the seat ring, and the rotational torque of the valve body is relatively low.
Moreover, it does not cause any damage.

Hereinafter, the configuration of this invention will be explained with reference to the drawings shown as one embodiment.

Reference numeral 1 denotes a valve body, and a seat ring 2 made of an elastic material such as rubber is fitted onto the inner peripheral surface of the valve body. 3 is a valve body, which is fixed to the valve shaft 4 inserted into the valve body 1 and is attached to the inner circumferential surface of the seat ring 2 so as to be pressable;
It is adapted to prevent fluid flow when closed. On the inner surface of the seat ring 2, excluding at least the shaft hole forming portion 5 of the valve shaft 4, there are inward protuberances 6, 6' on both sides corresponding to the front and back positions of the valve body 3 when fully closed, approximately semicircularly. The valve body 3 is designed to come into pressure contact with the side edges of the inner protuberances 6, 6' when closed.
7 is an O-ring, 8 is a bushing, and 9 is an annular protrusion provided on the inner surface of the shaft hole forming portion 5 of the seat ring 2 to prevent leakage along the valve shaft 4.

Regarding the shapes of the peripheral edge of the valve body 3 and the inner protrusions 6, 6' of the seat ring 2, as shown in the drawings, the peripheral edge of the valve body 3 is shaped like the tapered part 1.
0, and the inner raised parts 6, 6' of the seat ring 2 have a substantially trapezoidal cross section, and a structure is adopted in which an inclined part 11 corresponding to the tapered part 10 is formed on the side edge, and by utilizing a wedge effect. It has the effect of increasing the sealing pressure and also being adjustable and controllable. Preferably, however, the inclination angle of the tapered portion 10 of the valve body 3 is slightly smaller than that of the inwardly protruding portions 6, 6' of the seat ring 2, for example, the angle relationship is 15° for the former and 30° for the latter. The sealing pressure can be further increased by the biting action. Furthermore, even when the inner protrusions 6, 6' are formed to have an inverted trapezoidal cross section, the inner protrusions 6, 6' are deformed and brought into close contact by the pressing action, regardless of the shape of the peripheral edge of the valve body 3. condition, and a good sealing effect can be obtained.

This device has the above-mentioned configuration, and has a structure in which the peripheral edge of the valve body 3 is brought into pressure contact with the side edge of the inner protrusion 6 provided on the seat ring 2 to prevent fluid from flowing. The sealing pressure from fully open to fully closed can be increased depending on the extent to which the angle θ is exceeded, as shown in FIG. 6, and a good closed state can be obtained. In addition, in this invention, a sealing state is obtained by pressing the peripheral edge of the valve body against the side edge of the inner bulge of the seat ring, so the valve body is pressed against the inner circumferential surface of the seat ring, unlike the conventional example. It does not dig in, so there is no risk of damage to the seat ring, and furthermore, it has the advantage that the rotational torque required when opening and closing the valve body is small.

Generally, the material of the seat ring must be a rubber suitable for the fluid, but because the shrinkage during vulcanization differs depending on the rubber material, if different materials are molded in one type of mold, the inside diameter of the seat ring will vary, so in the conventional seat rings shown in Figures 7 and 8, there is a problem that the sealing state between the valve body and the seat ring is incomplete and the sealing pressure is reduced, and several types of molds for the seat ring are required depending on the material.
An inwardly raised portion is formed on the inner surface, and a seal is formed between the side edge and the periphery of the valve body. This means that even if there is some variation in the inner diameter of the seat ring, the pressure contact between the valve body and the seat ring and the sealing pressure can be maintained without any problems. Furthermore, one type of seat ring mold can be used sufficiently even if different rubber materials are used.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the butterfly valve according to this invention, Fig. 2 is a longitudinal sectional view of Fig. 1, Fig. 3 is a longitudinal sectional view of the seat ring, and Fig. 4 is a front view of the valve body. 5 is a cross-sectional view of the valve body and the seat ring, FIG. 6 is a diagram illustrating the operating state of the valve, and FIGS. 7 and 8 are diagrams illustrating the operating state of the conventional valve. 1... Valve body, 2... Seat ring, 3... Valve body, 4... Valve stem, 5... Shaft hole forming part, 6, 6'
...Inner raised portion, 7...O ring, 8...Button, 9...Annular protrusion, 10...Tapered portion, 11
...Slope section.

Claims (1)

[Claims for Utility Model Registration] (1) A valve that forms a fluid flow path attached to the inner surface of the body and has a press-contact sealing surface on the periphery of the valve body that is opened and closed by the valve shaft inserted through the shaft hole. In a butterfly valve having a seat ring that allows opening and closing of the passage, a tapered portion is formed on the peripheral edge of the valve body, and the valve body is formed approximately half a circumference at a time on the inner surface of the seat ring, excluding at least the shaft hole forming portion, when the valve is fully closed. A butterfly in which an inward protrusion is provided at the front and back positions of the body, and an inclined part is formed on the side edge of the inward protrusion to which the tapered part of the valve body presses, and the inclined part is used as a press-contact seal surface to which the front and back peripheral edges of the valve body come into pressure contact. valve. (2) The butterfly valve according to claim 1, wherein the angle of inclination of the tapered portion of the valve body is slightly smaller than the angle of the inclined portion of the inwardly protruding portion of the seat ring.