JPS6051765B2 - Fuse filled with powder arc quenching agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuse filled with a powder arc-extinguishing agent, and particularly to a plug for an arc-extinguishing agent filling hole.

Conventionally, the arc-extinguishing agent filling hole in this type of fuse was generally sealed as shown in FIGS. 1 and 2.

Figure 1 shows a method of covering with epoxy resin, etc. from the outside. 1 is an outer cylinder, 2 is a cap, 3 is an arc-extinguishing agent filling hole, 4 is a fuse element, 5 is an arc-extinguishing agent, and 6 is a plug for epoxy resin, etc. It is. With this method, the adhesive strength between the epoxy resin, etc. and the cap may deteriorate over time (this phenomenon is particularly noticeable in outdoor fuses), the plug may come off due to thermal softening of the epoxy resin, etc., or the internal pressure during fuse operation may There was a drawback that the stopper could come off.

FIG. 2 shows a method to prevent these cracks, which is applied particularly to fuses under high internal pressure during operation, where 7 is a screw plug and 8 is a cover made of epoxy resin or the like for sealing.

Compared to the method shown in FIG. 1, this method takes more time to assemble, such as thread cutting, and increases costs. Furthermore, like the one shown in FIG. 1, the covering made of epoxy resin or the like has various drawbacks, such as the fact that it may come off due to deterioration of adhesion strength over time, especially in outdoor fuses. Furthermore, both the fuse shown in FIG. 1 and the fuse shown in FIG. 2 have the disadvantage that the external dimensions of the fuse are large because the plug is provided on the outside. An object of the present invention is to provide a fuse that does not have the above-mentioned drawbacks, has a simple structure, is easy to maintain correct external dimensions, and does not become unplugged due to deterioration of adhesive strength over time.

In order to achieve the above object, the fuse filled with powder arc quenching agent according to the present invention is non-solid during injection and has a larger diameter than the filling hole diameter provided inside and in contact with the arc quenching agent filling hole. The gist is that the filling hole is sealed with a plug made of a solidifying material.

An example of its structure and manufacturing method will be explained below with reference to FIGS. 3 and 4, but this is merely an example, and it goes without saying that various improvements and modifications can be made within the framework of the present invention. be.

After filling the fuse cylinder with the arc-extinguishing agent 5, pass it through the filling hole 3 and tamp it down with a thin copper rod, or take out a small amount of the arc-extinguishing agent 5 and fill it with a third A gap 9 as shown in the figure is provided.

In this case, the powder arc extinguishing agent, for example commonly used silica sand, has fluidity as seen in the shape of a mortar in an hourglass or an ant hell, so the powder extinguisher directly below it passes through the filling hole 3. When the arc agent is tamped with a thin copper rod to increase its density, the surrounding powder arc extinguisher (the powder arc extinguisher filled directly under the periphery of the filling hole 3) will fill the reduced area (bulk). The water flows in, forming a mortar-shaped void that resembles an ant hell.

As a result, the diameter D4 of this gap becomes larger than the diameter D2 of the filling hole. Further, when a small amount of powder arc extinguishing agent is sucked out from the filling hole 3 by a vacuum pump or scooped out with an earpick-like tool, a mortar-shaped void is similarly formed. Also in this case, the diameter D4 of this gap is larger than the filling hole D2. After that, when a liquid filler such as epoxy resin is filled into the gap 9 through the filling hole 3 and hardened, a plug 10 having a diameter D4 larger than the diameter D2 of the filling hole is formed in the fuse cylinder as shown in FIG. Get inside. As described above, according to the method of the present invention, since the plug having a diameter larger than the filling hole is provided inside the fuse tube, the adhesion strength between the plug made of epoxy resin and the cap deteriorates over time. Even if this occurs, the stopper will not fall, and even if the resin softens to some extent due to the heat generated during fuse operation, it can withstand much greater internal pressure than conventional fuses.

The workability is not much different from the conventional one shown in Fig. 1, and furthermore,
Since the plug is provided on the inside, various advantages can be obtained, such as the fact that the external dimensions of the fuse do not increase.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the structure of the plug of the arc-extinguishing agent filling hole of a fuse filled with a conventional powder arc-extinguishing agent, and FIGS. 3 and 4 show the powder arc-extinguishing agent according to the present invention. FIG. 3 is a cross-sectional view showing the manufacturing process of a fuse filled with Throughout each figure, the same reference numerals indicate the same or equivalent parts, and in the figures, 1 is the outer cylinder, 2 is the cap, 3 is the arc-extinguishing agent filling hole, and 4
is a fuse element, 5 is an arc extinguishing agent, 6 is a plug made of conventional epoxy resin, 7 is a screw plug, 8 is a cover made of epoxy resin, etc., 9 is a gap, 10 is a plug made of epoxy resin, etc. of the present invention,
D2 is the diameter of the arc-quenching agent filling hole, and D4 is the diameter of the void.

Claims (1)

[Claims] 1. The filling hole is sealed with a plug made of a material that is in contact with the arc-extinguishing agent filling hole and has a larger diameter than the filling hole provided inside and is non-solid during injection and solidifies after injection. A fuse filled with powder arc extinguishing agent.