JPS6244214Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an annular sheet composition having excellent heat resistance and corrosion resistance, which is used particularly as a sealing member for gate valves, ball valves, butterfly valves, and the like.

Regarding a conventional valve seat composition formed by combining an elastic body and a metal base member, for example,
The one described in Publication No. 67114 is known,
In addition, regarding elastic bodies covered with a coating layer made of fluorocarbon resin, Japanese Patent Application Laid-Open No.
The one described in Japanese Patent No. 53-129327 is known.

As shown in FIG. 2, the seat ring of the chisel-shaped valve disclosed in the former is made of an elastic material made of rubber, synthetic resin, etc., and has a substantially U-shaped cross section. It is constructed by combining an annular ring member and a core made of a rigid material such as metal and having a convex portion that fits into a recess of the member.

This seat ring is certainly effective for normal temperature applications, but when used for high-temperature fluids, deformation of the elastic material in the torsional direction can be prevented because it is reinforced with a rigid material. A problem arises in that the elastic material that comes into direct contact with the material becomes hard and reduces sealing performance.Furthermore, when used for corrosive fluids such as chlorine gas (especially those at high temperatures), the elastic material erodes, and furthermore, as a rigid material, This causes problems such as a decrease in sealing performance, that is, leakage of fluid, metal rust mixed into the fluid, and a decrease in reinforcing effect due to metal corrosion.

In order to solve these problems, as disclosed in the latter, vinylidene difluoride resin (hereinafter referred to as
The elastic material is coated with a fluorine-based resin coating layer such as PVDF (hereinafter abbreviated as PTFE) or tetrafluoroethylene resin (hereinafter abbreviated as PTFE) to prevent deterioration of the elastic material due to solidification or corrosion caused by high temperatures or corrosive fluids. There are ways to prevent this.

However, even if the elastic material of the seat ring is coated with a fluororesin, the heat resistance and corrosion resistance are improved and the service life is extended. However, when used for high-temperature corrosive fluids,
Even fluororesins are permeable to a certain degree of moisture and corrosive gases such as wet chlorine gas, so that over a long period of use, the rigid material as well as the elastic material will corrode, resulting in the problems described above.

This idea was made in view of the problems of the conventional technology as described above, and its purpose was to solve the above problems by creating a reinforced material with excellent heat resistance, corrosion resistance, and sufficient resistance to high-pressure valve closing force. An object of the present invention is to provide an annular valve seat composition having a structure such that one half thereof is steeply sloped so that its inner surface is left-right asymmetrical in a free state. The other half has a convex surface with a gentle slope, and the exposed surface is covered with a coating layer made of fluorine-based resin, and the metal base member whose entire circumference is coated with fluorine-based resin. The present invention is characterized by a combined valve seat composition.

However, when actually using the valve seat composition of the present invention, it is necessary to treat room-temperature gas or liquid instead of high-temperature fluid, or to treat air or ordinary water instead of chlorine gas. This does not prevent it from being used to process things like this.

Now, one preferred embodiment of this invention illustrated in the drawings will be described in detail below.

The valve seat composition according to the present invention is designated as a whole by the reference numeral 1 and is shown in the drawings as a longitudinal section thereof. This sheet composition 1 includes a rubber, elastomer, or similar elastic body 2 as a sealing main body, includes an on/off acting part for fluid on its inner surface, and has a fluorine-based material having corrosion resistance on its outer surface. Resin, preferably PVDF
(vinylidene difluoride resin) or PVDF
It is coated with PTFE (tetrafluoroethylene resin) and constitutes the coating layer 3. In the latter case, there will be two covering layers 3, which are not shown in the drawings.

In the illustrated example, the covering layer 3 is formed in the shape of a compound curve with a steep slope on the left half and a gentle slope on the right half, and a small straight section 3a is interposed in a part, but this part is absent. You can. In the illustrated example, the left half is configured as a multipurpose type that can be used for a ball valve and the right half for a butterfly valve as needed.

Reference numerals 4 and 5 are preferably semicircular (as illustrated), channel-shaped, or similar annular cavities, which are provided on the outer annular surface of the elastic body 2. In the illustrated example, two valves are provided, but in the case of a small valve, the valves may not be provided, or may be reduced to one. Conversely, in the case of a large valve, the number may be 3 to 5. In any case, the purpose of providing the annular spaces 4 and 5 is to increase the pressurization stability of the elastic body 2.

Reference numeral 6 denotes a metal base member whose cross section is formed into a rectangular shape, a stepped rectangular shape (in the case of the illustrated example), or a trapezoidal shape, and its entire circumference, that is, its entire surface, is coated with the same fluorine-based resin as above. It is coated with layer 3, which improves its chemical resistance.

The function of this product is the same as that of conventional products except that it can be used for multiple purposes, and it can be effectively used as a mating member for ball valves, butterfly valves, etc. (not shown in the drawings). However, the illustrated state corresponds to when the valve is open, and the operating surface has a convex curve, but when the valve is closed, it is pushed by the valve member, which has a convex curve, and a part of the inner surface has a concave curve. present.

Since the present product has the above-mentioned structure and function, it has sufficient chemical resistance and heat resistance due to the presence of the coating layer 3 all around it, and also has the metal base member in the outer layer. Since it is designed to support the valve pressure, even if the valve member is forcefully closed as necessary, it can withstand it sufficiently and achieve a tight sealing effect.
And its useful life is long.

Furthermore, since the entire circumference of the metal base member is coated with fluorine-based resin, the metal base member will not corrode, and its useful life can be extended even when the seat is used under severe usage conditions. And since this metal base member and the elastic body are not integrated but have a combined structure,
It is only necessary to replace the elastic body, which tends to corrode and become damaged during long-term use, and the metal base member can be used continuously.

Furthermore, since the inner surface of the elastic body has a specially shaped convex surface that is asymmetrical, one seat can be used for both ball valves and butterfly valves.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view showing an example of a valve seat composition according to the present invention. In this figure, 1...valve sheet composition, 2
... Elastic body, 3 ... Covering layer, 4, 5 ... Annular cavity, 6 ... Metal base member.

Claims (1)

[Scope of utility model registration request] An elastic body whose inner surface is asymmetrical in the free state, with one half having a steep slope and the other half having a gentle convex surface, and the exposed surface of which is covered with a coating layer of fluorine-based resin. and a metal base member whose entire circumference is coated with fluorine-based resin.