JPS6110048Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Field of the invention This invention is a compression recovery system used in parts that require chemical resistance and insulation, such as flange connections of pipes for transferring chemicals, oil, gas, etc. The present invention relates to a gasket having special characteristics.

(b) Background of the invention As shown in Fig. 1, a gasket with compression-recovery properties currently used in this type of piping is an annular core 3 made by lining the outer circumferential surface of an annular metal plate 1 with rubber 2. A gasket 5 constructed by covering a ring body 4 made of fluorine resin is generally used. In this gasket 5, the rubber 2 is reinforced by the metal plate 1, but when heat exceeding room temperature is applied to the rubber 2 during use, the elasticity of the rubber 2 decreases and the rubber A protrusion phenomenon occurs in the outer part of the rubber 2, and the rubber 2 becomes thin.As a result, the pressure resistance against tightening of the gasket decreases, and not only does the sealing function deteriorate significantly, but the rubber 2 breaks down and the insulation function decreases. There were also drawbacks.

In addition to this type of gasket, which utilizes the compression recovery properties of a metal plate with a rubber coating layer on both sides and uses it as a core, there is a gasket that uses a joint sheet made of asbestos or asbestos as the core. There are also gaskets that are coated with fluorine resin.

However, in the case of such a gasket whose core is made of a joint sheet, it is heat resistant and the above-mentioned "extrusion phenomenon" is less likely, but as shown by symbol A in Fig. 2, the strain margin after compression is low. A is approximately 0.05 mm, which is extremely small at approximately 1/10 of the strain margin B of a gasket with a rubber coating layer as the core, which is 0.5 mm.For this reason, the range of application of gaskets made of joint sheets is limited. Even if the flange etc. is distorted, it has a disadvantage that the ability to absorb the distortion is reduced.

In this way, conventional gaskets with compression-recovery characteristics (so-called fluorine resin encased gaskets) have a relatively large amount of distortion, and even when heat exceeding room temperature is applied, the core does not protrude. There is no ideal gasket free from this phenomenon, and such a gasket has been desired in the industrial market.

(c) Purpose of the invention Among the two types of gaskets as described above, the present invention utilizes the advantage of the former gasket in which the rubber coating layer is used as the core, which has a large distortion allowance, while also making use of the annular core. The object of the present invention is to solve the above-mentioned drawbacks by preventing the rubber coating layer from extruding, and to provide a gasket that is extremely easy to manufacture and exhibits excellent properties.

(d) Summary of the invention This invention provides a rubber coating layer integrally on the outer peripheral surface of an annular metal plate, and a reinforcing cloth made of a fiber material such as cotton cloth, phenol fiber cloth, glass cloth, etc. on the entire surface of the rubber coating layer. This gasket is formed by fitting an annular core integrally formed by winding and vulcanization bonding into an annular groove on the outer periphery of a fluororesin ring body.

(e) Effects of the invention According to the invention, even when used for a flange of a piping connection, for example, and heat above room temperature is applied, the rubber coating layer can be wrapped around the entire surface and integrated with vulcanization adhesive. The reinforced fabric completely eliminates the ``extrusion phenomenon'' that tends to spread greatly in the radial direction.

In other words, in the conventional product as shown in Figure 1, when heat above room temperature is applied, the elasticity of the rubber coating layer is extremely reduced, and as a result, the tightening force of the flange causes the rubber coating layer to have a low coefficient of friction. The side that is in contact with the fluorine resin ring body tends to expand radially, but the reinforcing cloth that is wrapped around the entire circumference of the rubber coating layer and integrated with vulcanization adhesive prevents the expansion in the radial direction. It is possible to completely eliminate phenomena such as destruction of the rubber coating layer, or extreme reduction in pressure resistance as a gasket.

Therefore, the present invention has the effect of maintaining a completely sealed and insulated state for a long period of time.

This showed the results of "Example" described later. This is also proven from Figures 4 and 5.

(f) Embodiment of the invention An embodiment of the invention will be described below in detail based on the drawings.

The annular core 6 of the present invention has a rubber coating layer 8 on the outer peripheral surface of an annular metal plate (steel plate 7), as shown in FIG. A reinforcing cloth 9 made of a fiber material such as cotton cloth, phenol fiber cloth, glass cloth, etc. is applied to the entire surface of the rubber coating layer 8 at the same time as the vulcanization adhesion.
are wrapped and vulcanized to form an integral piece.

As shown in FIG. 4, the annular core 6 constructed in this manner is fitted into an annular groove 10a on the outer periphery of a ring body 10 made of fluorine resin to form a gasket 11.

The following experiment was conducted to investigate the characteristics of the gasket 11 according to the present invention described above.

Experimental example As a comparison product, punched metal (inner diameter 105mm
φ, outer diameter 144mmφ, thickness 0.8mm, punching hole 2.5
mmφ, punching aperture ratio 30%) and rubber (NBD,
A gasket was prepared in which a ring-shaped core with a thickness of 3.3 mm was formed by coating the core with a hardness of 75°), and this was inserted into a fluorine resin package that matched the flange dimensions for JIS20K-300A.

As the product of the present invention, a glass cloth tape (WF300 manufactured by Nittobo Co., Ltd., 10N plain weave thickness 0.26 mm) was further wrapped around the annular core formed of the above-mentioned comparative product.
An annular core was formed by vulcanization and adhesion at the same time as rubber, and this was inserted into a fluororesin package with JIS20K-300A flange dimensions to form a gasket.

As a result of looking at the compression characteristics of each gasket, as shown in FIG. 5, it can be seen that the compressive strain of the product of the present invention is extremely small, and the phenomenon of extrusion in the radial direction is prevented.

Furthermore, the gasket coefficient r (r=
As a result of investigating the actual tightening surface pressure/fluid pressure at the time of leakage start), as shown in Figure ⁶ , the gasket coefficient r of the present product was
It is almost flat at 1.5 to 1.0, and the comparative product is 2.5 to 2.0.
We obtained very small results compared to .

As is clear from the above experimental examples, the product of this invention has relatively small compressive strain against the clamping surface pressure, exhibiting appropriate characteristics, and the amount of strain is reduced due to the prevention of extrusion. On the other hand, it has compressive strain characteristics such as flanges with strain absorption ability, and the gasket coefficient r is small and stable. It can be seen that this gasket structure can stop the liquid to be sealed even if the tightening force of the tightening bolt is small, and can also be applied to high-pressure fluids. In other words, it has a great technical effect as a gasket.

Furthermore, it goes without saying that the annular core 6 of the present invention can be used as a stand-alone gasket without covering the fluorine resin ring body 11 in applications where chemical resistance and insulation are not so required. .

As shown in the examples above, the gasket of the present invention has the following features:
Since a reinforcing cloth made of fibrous material is wrapped around the entire surface of the rubber coating layer of the annular core and is integrally provided with vulcanization adhesive, the diameter of the rubber coating layer is determined by the pressing force applied to both sides of the gasket due to the tension of this reinforcing cloth. Since the spread in the direction is reliably prevented and the elasticity of the rubber coating layer in the tightening direction does not decrease, it is possible to eliminate the phenomenon of extrusion or destruction of the rubber coating layer. Therefore, the sealing and insulating functions of the gasket can be maintained for a long period of time.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional gasket, Figure 2 is a graph comparing the compression and recovery characteristics of a gasket with a rubber coating layer as the core and a gasket with a joint sheet of asbestos or the like as the core. The figure is a partially cutaway perspective view of the annular core of the present invention, Figure 4 is a sectional view of the gasket of the present invention, Figure 5 is a graph showing the compression characteristics of the product of the present invention and a comparative product, and Figure 6 is a gasket. FIG. 7 is a graph showing the coefficients of . 6... Annular core, 7... Annular metal plate, 8...
Rubber coating layer, 9... Reinforcement cloth, 10... Fluorine resin ring body, 11... Gasket.

Claims (1)

[Claims for Utility Model Registration] A rubber coating layer is integrally provided on the outer peripheral surface of an annular metal plate, and a reinforcing cloth made of a fiber material such as cotton cloth, phenol fiber cloth, or glass cloth is wrapped around the entire surface of the rubber coating layer. A gasket formed by fitting an annular core, which is integrally provided by attaching and vulcanizing adhesive, into an annular groove on the outer periphery of a fluororesin ring body.