JPH0778211B2 - High temperature gasket - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket used in equipment operating at high temperature such as a high temperature device,
That is, it relates to a high temperature gasket.

[0002]

2. Description of the Related Art Asbestos joint sheet gaskets have hitherto been generally known as non-metal gaskets used in high-temperature equipment. However, this asbestos joint sheet gasket has a maximum operating temperature of 500 ° C. The predetermined sealing performance cannot be exhibited at high temperatures.

Therefore, the applicant of the present invention discloses a non-metallic gasket which raises the limit of the operating temperature and exhibits excellent sealing performance even at a high temperature of 1000 ° C. Has proposed a high temperature gasket as disclosed in US Pat. The above-mentioned high-temperature gasket is composed of glass-based fibers or glass-based powders 5 to 40 wt% and inorganic powders 30
˜90 wt%, organic binder 30 wt% or less, and the porosity is 50% or less.

[0004]

A high-temperature gasket having the above basic composition is a softened glass fiber when used at a temperature near or above the softening point of the glass fiber or glass powder. Alternatively, the glass-based powder fills the voids of the gasket and exhibits excellent sealing performance at high temperatures. On the other hand, the glass-based fiber or the glass-based powder is hardened in a state where the temperature is lowered from a high temperature to a normal temperature, but during the hardening, a warp or a void is generated in the gasket, which causes the temperature of the heat cycle at a normal temperature There was room for improvement in that the leak amount was still large.

The applicant of the present invention has also found that the glass fiber having a relatively small fiber diameter of 2 μm is 5 to 15 wt%, the sepiolite mineral is 5 to 30 wt%, and the talc mineral is 50 to 80 wt%.
% And the organic binder is 10 wt%, the porosity is 5
We also propose a high temperature gasket composed of 0% or less. The high-temperature gasket having such a composition can maintain the sealing property at high temperature and can reduce the leak amount at normal temperature, but since the heat shrinkability and heat loss of the sepiolite mineral are large, the strain deformation during the heat cycle occurs. It is easy to happen and there is some concern about the sealing performance.

The present invention has been made in view of the above circumstances, and is capable of maintaining excellent sealing performance at high temperatures and reducing the amount of leakage at room temperature, and sealing reliability without being affected by thermal cycles. It is intended to provide a high temperature gasket having a high temperature.

[0007]

In order to achieve the above object, a high temperature gasket according to the present invention comprises a ceramic fiber of 8 to 12 wt% and a sericite mica mineral of 18 to 22 wt%.
%, Talc mineral 62-66 wt%, organic binder 2-6w
It is composed of t% and has a porosity of 60% or less.

[0008]

In the high temperature gasket having the above construction, each compounding material plays the following role. Ceramic fibers reinforce the gasket to retain its shape and prevent heat shrinkage. Since the sericite mica mineral has a sinterability, it forms the skeleton of the gasket in a sintered state, which helps prevent the shape from deforming at high temperatures. Further, this sericite mica mineral has little heat shrinkage and heat loss, and therefore strain during use is suppressed, and moreover, CaO, MgO, K ₂ O, N
The glaze component such as a ₂ O is melted and softened to exhibit a high sealing property. Since talc mineral has extremely flexible physical properties, it not only gives flexibility to the gasket, but also serves as a high-density powder filling material, has little heat shrinkage, and has no sinterability. It greatly contributes to the improvement of stopping performance.

Further, the organic binder has a role of holding the shape of the gasket at the initial room temperature, and when it is heated, it is thermally decomposed and disappears. Therefore, it is desirable that the content of the organic binder is small. In the high temperature gasket of the present invention, since the sericite mica mineral is also mixed, the compounding amount of the organic binder can be about 2 to 6 wt%. The organic binder is preferably an ethylene-based terpolymer such as an ethylene-acrylic acid ester copolymer or an ethylene-vinyl chloride terpolymer. The reason is that the skeleton-forming function such as hardness and adhesive strength is excellent, and that the emulsion has good polymerization stability and excellent workability.

[0010]

Embodiments of the present invention will be described below. First,
Sericite Mite Mineral (made by Murakami Sericite), Kaolin Mineral (made by Shiraishi Calcium: trade name Burgess # 10), Sepiolite Mineral (made by Showa Mining: trade name Milcon MS-2-) that has sinterability when heated at 1000 ° C. 2) was made into a sheet with the composition shown in FIG. 1, and the sheet produced had a surface pressure of 1.4 kg / c.
While pressing with an indenter of m ² , 200 to 900 ° C (720
Min) was repeated 5 times, and then the heat shrinkage ratio was measured. Similarly, the same measurement was performed for talc mineral (manufactured by Nippon Talc: trade name talc MS). For these measurements, a differential thermal analyzer (manufactured by Shimadzu Corporation: TMA-5
0) was used.

The loss on heat of each of the above minerals was also measured. The measurement result is shown in FIG. As is clear from these results, the thermal contraction rate and thermal loss of the sericite mite mineral are much smaller than that of the sepiolite mineral, and therefore, it is the most suitable as a sinterable mineral. However, it can be seen that the combined use with talc mineral, which is not sinterable but is flexible, is effective in suppressing contact surface leakage.

Here, after a sheet having a composition shown in FIG. 3 (as an organic binder, a papermaking pulp and an acrylic ester emulsion are used in combination) is prepared by a papermaking method, a press treatment is performed to form voids. Sheet gasket with a rate of 45% (outer diameter 55 mm, inner diameter 35 mm, thickness 1 m
m) is molded, and the molded gasket is subjected to a sealing test with a test device as shown in FIG. In FIG. 5, 1
Are electric furnaces, 2A and 2B are upper and lower sample gaskets, and 3 to 5 are flanges made of a high nickel alloy or the like and constituting a seal seat surface. The upper sample gasket 2A is sandwiched between the flanges 3 and 4, and the lower sample gasket 2B is sandwiched between the flanges 4 and 5. 6 weight, N ₂ gas cylinder for supplying N ₂ gas to the machine 9 through the pressurized pressure pipes 8 7, 10 valve, 11 is a pressure gauge.

The test method is as follows.
tightened by tightening surface pressure kgf / cm ^2, to set the lower gasket 2B the state where the clamped 0.31kgf / cm ² tightening surface pressure, the pressure in the apparatus 9 in this state 0.1 kgf /
After the N ₂ gas of cm ² is filled, the valve 10 is closed, and the leak amount is obtained from the time decrease rate of the pressure with the pressure gauge 11. At room temperature → 1000 ° C → at room temperature → 10
The amount of leak at the time of applying a thermal cycle of 00 ° C → 1000 ° C at room temperature → room temperature is measured. The result of the seal test is shown in FIG. The leak amount shown in FIG. 4 is the amount of each gasket with the initial leak amount being 10.

On the other hand, the porosity α is defined as follows. α = 1- (γ / ρ) {ρ: true specific gravity, γ: bulk density (weight / volume)} The ceramic fiber is Toshiba Monoflux HSA fiber (trade name: manufactured by Toshiba), and ethylene co-gravity is used. For the combination, Sumika Flex 900 (trade name: manufactured by Sumitomo Chemical Co., Ltd.) was used. As the hemp pulp, Manila hemp pulp (Ogura Trading) was used. The true specific gravities of the materials used were calculated as follows, and the porosity was calculated. Ceramic fiber 2.6g / cm ³ , Kaolin mineral 2.6g / c
m ³ , sepiolite mineral 2.6 g / cm ³ , talc mineral 2.8 g / cm ³ , sericite mica mineral 2.5 g / c
m ³ , ethylene copolymer 1.05 g / cm ³ , hemp pulp 0.9 g / cm ³ .

As is clear from the results of the seal test shown in FIG. 4, the heat shrinkage and heat loss of Comparative Example 1 are relatively large, so that the influence of the thermal cycle appears. The increase of the leak amount from the second cycle is remarkable. On the other hand, the high-temperature gaskets of the examples of the present invention show a small amount of leakage at a high temperature of 1000 ° C. and at room temperature, and exhibit excellent sealing performance. This is because the heat shrinkage and heat loss of the sericite mica mineral are small, and Ca
This is because the glaze components such as O, MgO, K ₂ O and Na ₂ O melt and soften. Further, this gasket is provided with flexibility by the talc mineral to suppress the leak on the contact surface, and also acts as a filling material to have a high density to reduce the permeation leak. Further, since it has a light sinterability, scattering of the gasket due to the sealing gas fluid is effectively prevented.

[0016]

As described above, according to the present invention, 10
Not only can excellent sealing performance be exhibited at a high temperature of 00 ° C., but also the amount of leakage can be extremely reduced at room temperature. In particular, in a thermal cycle between a high temperature of 1000 ° C. and room temperature, strain deformation is small, and the glaze components such as CaO, MgO, K ₂ O, and Na ₂ O are melted and softened, so that the sealing performance is improved. It is possible to obtain a high-temperature gasket that can significantly improve the temperature.

[Brief description of drawings]

FIG. 1 is a diagram showing a heat shrinkage ratio of a single paper of an inorganic mineral such as sericite mica mineral used in a high temperature gasket according to an embodiment of the present invention.

FIG. 2 is a diagram showing a thermal loss of inorganic minerals such as sericite mica minerals.

FIG. 3 is a view showing the composition of each gasket of Example, Comparative Example 1 and Comparative Example 2.

FIG. 4 is a diagram showing, in comparison, the seal test results of the gaskets of Example, Comparative Example 1 and Comparative Example 2.

FIG. 5 is a schematic diagram of a test apparatus used to test the sealing performance of each gasket.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokumi Satake 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe, Hyogo Prefecture Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (72) Masayuki Funatsu, Hyogo-ku, Kobe, Hyogo Prefecture 1-1-1 Wadazakicho Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (72) Inventor Satoshi Hashimoto 2-6-66 Nagata, Fukuchiyama City, Kyoto Prefecture 3 Pillar Industry Co., Ltd. Fukuchiyama Factory (72) Inventor Satoshi Tanimura 3-66, Nagatano, Fukuchiyama, Kyoto Prefecture, Japan Fukuchiyama Factory, Japan Pillar Industry Co., Ltd. (56) References JP-A-64-62381 (JP, A) JP-A-56-41284 (JP, A) JP-A-51 -86659 (JP, A)

Claims (1)

[Claims] 1. Ceramic fiber 8 to 12 wt%, sericite mica mineral 18 to 22 wt%, talc mineral 62 to 6
A high temperature gasket comprising 6 wt% and an organic binder of 2 to 6 wt% and having a porosity of 60% or less.