JPH0333951B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fire-resistant gasket suitable for use in pipe joints.

[Conventional technology]

As a fireproof mechanical pipe joint that has been conventionally employed, there is, for example, one shown in FIG. 4.

That is, in this FIG. 4, the reference numeral 11 is a metal pipe to be connected, and the reference numeral 12 is a pipe joint for connecting the metal pipes 11 to each other, and a metal joint body 13 is screwed to the joint body 13. It is composed of a metal press ring 14 whose inner peripheral surface is tapered as a tapered surface 14a to be fixed, a gasket 15 housed in the inner circumference of the joint body 13, and 16 the press ring 14 and the gasket 15. A retainer 17 is interposed between the tapered surface 14a of the press ring 14 and
A plurality of balls 17b having a predetermined mechanical strength are placed at equal angles within an annular holding band 17a made of chloroprene rubber or the like containing a predetermined amount of thermally expandable graphite. It is maintained at intervals.

However, in the case of such a conventional configuration, when a flame hits, the gasket 15 is burned out, while the thermally expandable graphite contained in the holding band 17a forming the ball band 17 expands several hundred times, causing the inside of the tube to be destroyed. It acts to minimize fluid leakage, but in this case, as the holding band 17a expands in volume due to thermal expansion, the expanded portion changes into a porous shape, and the fluid in the tube leaks through the porous interior. I had a problem.

[Purpose of the invention]

This invention was made in view of these conventional problems, and its purpose is to
Even if a gasket containing unexpanded graphite expands thermally due to heating, by regulating the amount of expansion within a predetermined range, for example, when used in a pipe joint, the gasket can be To provide a fireproof gasket which can effectively prevent gas leakage.

[Structure of the invention]

In order to achieve the above object, the fire-resistant gasket of the present invention is made by densely braiding fire-resistant fiber materials such as glass fibers and alumina fibers into a sleeve, which is smaller than the inner circumference of the sleeve and which expands thermally when heated. A packing material such as synthetic rubber containing a predetermined amount of unexpanded graphite is inserted into the interior.

〔Example〕

Hereinafter, one embodiment of the refractory gasket according to the present invention will be described in detail with reference to FIGS. 1 to 3.

Fig. 1 is a cross-sectional view of the refractory gasket according to this embodiment, Fig. 2 is a cross-sectional view of the same in a state of thermal expansion, and Fig. 3 is a cross-sectional view of the main part of the refractory gasket applied to a pipe joint. In each figure of these embodiments, the same reference numerals as in the conventional example in FIG. 4 indicate the same or corresponding parts.

In this embodiment, the refractory gasket 18 is constructed as follows. That is, a fire-resistant fiber material such as glass fiber or alumina fiber that will not be destroyed even in the event of a fire is used, and this fiber material is densely braided into a bag-like or pipe-like shape to form a strong sleeve 19. This sleeve 19 is used as an outer layer, and the inside thereof contains a synthetic rubber containing a predetermined amount of unexpanded graphite, which is smaller than the inner circumference of the sleeve 19 and has the property of thermally expanding hundreds of times when heated from the outside in the event of a fire. The packing material 20 is inserted and internalized, and further formed into an arbitrary shape that fits the sealing part.

Here, the fireproof gasket 18 according to this embodiment
Since it is composed of a braided sleeve 19 and a packing material 20 such as synthetic rubber inserted into the sleeve, it can be easily molded into any shape that fits the sealing part. The refractory gasket 18 is, for example, as shown in FIG.
The inner diameter of the sleeve 19 and the proportion of the unexpanded graphite contained in the packing material 20 may be appropriately set depending on the purpose.

And the fireproof gasket 18 in this configuration shown in FIG.
In pipe joints to which this is applied, in the event of a fire, the packing material 2 containing unexpanded graphite is destroyed by external heating.
0 fully expands into the strong sleeve 19 which is densely braided in the shape of a bag or pipe, and reliably maintains the sealing effect between the part where it is arranged, that is, the metal pipe 11 to be connected and the joint body 13. You get it.

Incidentally, according to the results of an actual fire resistance test, in the case of a connected metal pipe heated at 800℃ for 30 minutes in a heating furnace and rated at 50A, the conventional configuration described above has a resistance of 70%.
However, in this embodiment, the leakage of fluid gas was 1/min, and the leakage prevention effect was sufficiently confirmed.

In addition, in some cases, pipe joints made of electrical insulation are used to break electrical continuity between the metal pipes to be connected, but in this case, the sleeve of the fireproof gasket is made of glass fiber, etc. If you use an electrically insulating sleeve, the electrical insulation property of unexpanded graphite is about 0.8MΩ, but the electrical resistance of glass fiber is about 1000MΩ, which makes it even more electrically insulating. We also confirmed that it is possible to achieve this.

Furthermore, in the tensile test after heating, the conventional configuration (Figure 4) could only withstand a tensile load of about 100 kg, but the configuration of the above example (Figure 3)
In Figure), it was able to withstand a load of 4,000 to 5,000 kgt, the same level as before the test, proving its superiority.

As described above, the fireproof gasket according to the present invention has various remarkable effects, but the fireproof gasket of the present invention is not necessarily limited to the case where it is installed in a pipe joint as in the above embodiment.
For example, like a split type pipe joint, it may be installed between one joint body and the other joint body that are divided into two, or around the pipe circumference. This can be used for anything that is unwell due to leakage of powder, etc.

〔Effect of the invention〕

As detailed above, according to the fire-resistant gasket of the present invention, when the packing material is heated due to a fire, the packing material tends to undergo a large thermal expansion due to the unexpanded graphite contained therein. Even if it expands, the expansion is regulated within a certain range within the sleeve, and there is no large amount of gas leaking from the expanded porous part as in the past.
Therefore, safety in the event of a fire can be significantly improved. Furthermore, since the fireproof gasket itself is subject to thermal expansion regulation within a certain range, the pipe fitting itself does not require any special structure to regulate this thermal expansion range; can be simplified.

In addition, in the case of the fire-resistant gasket of the present invention, since the packing material is formed smaller than the inner circumference of the sleeve, it is easy to insert the packing material into the sleeve, and the fire-resistant gasket can be manufactured easily. There is.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the general configuration of one embodiment of the refractory gasket according to the present invention, Fig. 2 is a cross-sectional view showing the state of thermal expansion of the same, and Fig. 3 is a cross-sectional view showing the above refractory gasket applied to a pipe joint. FIG. 4 is a cross-sectional view showing an outline of a pipe joint structure according to the conventional example. 11... Metal pipe to be connected, 12... Pipe joint, 13
...Metal joint body of pipe joint, 14...Metal push ring of pipe joint, 15...Packing, 16...Retainer, 17...Ball band, 18...Fire-resistant gasket, 19...Made of fire-resistant fiber material sleeve,
20...Packing material containing unexpanded graphite.

Claims (1)

[Claims] 1 A packing material such as synthetic rubber containing a predetermined amount of unexpanded graphite that is smaller than the inner circumference of the sleeve and thermally expands when heated, inside a sleeve made of densely braided fire-resistant fiber materials such as glass fibers and alumina fibers. A fireproof gasket with a material inserted inside.