JPS597069B2 - butterfly valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a butterfly valve having a resilient valve seat.

Conventionally, a snap-in type ring made of an elastic material such as rubber has often been used for the valve seat of a backfly valve, as disclosed in Japanese Patent Publication No. 39-6928.

However, the valve seat must withstand the tightening of the flange and must not move, ripple, or bulge under fluid pressure during use.

For this purpose, a valve seat made only of elastic material lacks rigidity.

A so-called cartridge valve seat has been improved in this respect, and includes an elastic valve seat 4 having a reinforcing member 6 made of phenol resin as shown in FIG. 1 or a cylindrical reinforcing member 6a as shown in FIG. Elastic valve seat 4a (Special Publication No. 48-134
No. 93) is known.

However, the former requires many machining steps to manufacture the reinforcing member.

Further, when molding the rubber member 5, the reinforcing member 6 is likely to be distorted, which requires additional machining.

Therefore, the former requires a long manufacturing process and increases costs.

In the latter case, the reinforcing member 6a is easy to manufacture, but when the reinforcing member 6a is included in the rubber member 5 by injection molding, the reinforcing member 6a is
Misalignment and distortion are likely to occur, making it impossible to achieve the desired performance.

In order to prevent this latter drawback, measures have been taken to make the reinforcing member 6a thicker or to increase the number of support points in the mold during injection molding, but if this is done, the manufacturing cost of the latter will eventually increase.

Further, the inside of the rubber member 5 in the former is not particularly reinforced, and in the latter, the reinforcing member 6a is in a floating state inside the rubber member 5, so both become unstable against fluid pressure during use.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a butterfly valve with an elastic valve seat that eliminates the above-mentioned drawbacks and has improved performance.

The butterfly valve of the present invention has a valve seat made of a rubber-like elastic material integrally molded with a reinforcing member, the reinforcing member is molded into a ring shape, and the reinforcing ring is provided with edges at both ends. The outside of the cylindrical part of the reinforcing ring is made into a void.

Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 3 is a sectional view showing an actual example of the present invention, in which an elastic valve seat 4b is mounted inside the valve box 1.

The valve body 2 is fitted into the valve stem 3 and fixed with bolts 11.

The valve rod 3 passes through the elastic valve seat 4b, and the valve body 2 is positioned within the elastic valve seat 4b.

A handle 12 is attached to the upper end of the valve stem 3, and its operation rotates the valve body 2 to open and close the flow path.

The backfly valve having the above configuration is configured to be clamped and tightened from both ends by pipe connection flanges (not shown).

The resilient valve seat 4b is shown enlarged in FIG. 4, and the reinforcing ring 6b is shown in FIG.

The reinforcing ring 6b is provided with edges 8a at both ends of the cylindrical portion 7.

The purpose of this edge 8a is to prevent the reinforcing ring from moving by fitting this outer peripheral part into a rubber mold during rubber molding, and also to serve as a partition wall to prevent the injected rubber from flowing into the gap 13.

Note that the hole 10 is a hole for inserting the valve rod 3.

The elastic valve seat 4b has a rubber member 5 on the outer surface of the cylindrical portion 7.
A void 13 is provided without adhesion.

As is clear from a comparison with FIG. 2, the first effect of the void 13 is that the use of the rubber member 5 is reduced, resulting in material savings.

The second effect is that, as shown in the closed state of the valve in FIGS. 1 and 2, the tip 2a of the valve body 2 contacts and presses the center portion 5a of the rubber member 5, and the repulsive force of the rubber member 5 at this time However, in the conventional example shown in FIGS. 1 and 2, this repulsive force depends only on the repulsive force of the rubber member 5, as is clear from the figures.

To explain this with reference to FIG. 7, when a repulsive force in the range of f1 to f2 is required, the tip 2a of the valve body 2 must bite into the central portion 5a of the rubber member. In this case, the valve body bites and deflects. It is necessary to control the amount of deflection within a very narrow range of al and a2 shown by A in FIG.

However, due to the effect of the flexible reinforcing ring in the rubber member + reinforcing ring + gap according to the present invention, the relationship between the repulsive force and the amount of deflection of the valve body is greatly improved compared to the conventional rubber member A alone, as shown in FIG. 7B. has a gentle slope and the same repulsive force f
1 and f2, it is sufficient to set the amount of deflection in a wide range of b1 and b2.

Since aI H a2 << b1 t b2 as above, the second effect of the present invention is that the amount of deflection can be controlled over a wide range during manufacturing, so even if the manufacturing process is a little rough, the leak-preventing effect can be sufficiently achieved, so it is better than the conventional method. It is a fried butterfly valve that is much easier to make.

FIG. 6 shows yet another example of a resilient valve seat.

This elastic valve seat 4c has a reinforcing ring with a further function of supplementing the sealing force of the rubber member 5.

The reinforcing ring 6c has its cylindrical portion 7 deformed to form a body portion 7 with a chevron-shaped cross section.
This is what I changed to a.

If the body has a chevron-shaped cross section, the reinforcing ring will be more flexible, so when the valve body 2 presses the rubber member 5, the chevron of the body 7a will open slightly, and the resulting repulsive force will cause the rubber member 5 to move against the valve body 2. begins to impose pressure on

As described above, the elastic valve seat used in the butterfly valve of the present invention is easy to manufacture and easy to maintain.

[Brief explanation of the drawing]

1 and 2 are partial sectional views showing a conventional elastic valve seat, FIG. 3 is a sectional view showing an actual case of the present invention, FIG. 4 is a sectional view taken along line A-A in FIG. 3, and FIG. The figure is a perspective view of the reinforcing ring, FIG. 6 is a partial sectional view showing another actual case of the present invention, and FIG. 7 is a diagram of repulsive force and the amount of deflection of the valve body biting to explain the effects of the present invention. . 1: Valve box, 2: Valve body, 3: Valve stem, 4, 4a to 4c: Elastic valve seat, 5b, 5c: Reinforcement ring, 8: Rim, A: Conventional rubber member only, B: Present invention Of things.

Claims (1)

[Claims] 1. In a butterfly valve having a valve seat made of a rubber-like elastic material integrally molded with a reinforcing member, the reinforcing member is formed into a ring shape, and the reinforcing ring is provided with edges at both ends;
A butterfly valve characterized in that the outside of the conical portion of the reinforcing ring is a void.