JPS6125165Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sealed fuse for protecting service lines.

In recent years, current-limiting fuses that have both a short-circuit cutoff section and an overload fusing section have been commonly used in fuses for protecting service lines branching from distribution lines in order to increase short-circuit capacity.

As shown in the conventional service line protection fuse, for example, as shown in Japanese Utility Model Publication No. 50-21607, there was one in which the fuse body was sealed in a transparent cylinder so that whether or not it was blown could be visually checked from the outside, but short-circuit interruption was possible. It was a closed type fuse with a complicated structure, consisting of resistance wires connected separately in parallel to the overload fusion section and the overload fusion section. However, such fusing display devices, etc.
In many cases, it is difficult to trust its operation.
These parts were subject to secondary accidents due to burnout, etc., and the structure and construction process of the fuses were further complicated, making them uneconomical.

The present invention is a sealed type fuse in which a short-circuit interrupting part and an overload fusing part are connected in series, and the internal fusing state can be directly checked, and the structure is simple and easy to manufacture. The present invention provides a hermetically sealed fuse that eliminates the need for a blowout indicator.

That is, the present invention preferably comprises a short-circuit breaker chamber that accommodates a short-circuit breaker element and is filled with post-arc-extinguishing powder, a hollow overload melting chamber that accommodates an overload breaker element, and a partition wall that separates these two chambers. The fuse has a transparent cylindrical body, a short-circuit breaking element extending through the short-circuit breaking chamber of the cylinder, and an overload fusing element extending through the overload fusing chamber, connected in series. The present invention relates to a hermetically sealed fuse consisting of a conductor body for use in the cylindrical body, the cylindrical body having a notch at one end, and the arc-extinguishing powder being injected through the notch during assembly. It is something.

Arc-extinguishing powder is used to prevent accidents such as electric arcs and ignition when the short-circuit interrupting element melts when it is necessary to interrupt a short circuit, so heat-resistant powders such as silica sand and alumina are suitable. However, white silica sand is particularly preferred in that the arc-extinguishing powder changes color and becomes easily visible when a short circuit is interrupted.

It is convenient to mold the short-circuit breaker chamber, overload melting chamber, and the partition wall that separates the two chambers from a heat-resistant resin with good insulation properties such as polyester resin, and to bury the above-mentioned conductor at the same time during this molding. It may be made into a split molded body, housed with a fuse conductor, and then bonded to complete the body.

The suitable material for the short-circuit interrupting element is a metal wire or thin plate made of a conductor with a relatively high melting point such as copper or silver, and the cross-sectional area is narrowed by narrowing the wire diameter or drilling holes in the thin plate to reduce the heat capacity of the part. is formed so that it melts down in the event of a short circuit.

The overload fusing element is a mass of a low melting point alloy containing lead or the like as a main component, and is installed in an overload fusing chamber that is provided axially adjacent to the short circuit breaking chamber containing the short circuit breaking element via a partition wall. will be installed.

These short circuit breaking elements and overload fusing elements are:
The integrated conductor body is connected in series and is formed as an integral conductor body by being connected in series to the conductor wires, each of which has a sleeve attached to both ends of the connected conductor body as a fuse, for connecting the above-mentioned lead-in wire, etc. They are embedded in the heat-resistant resin molded body so as to extend through the short-circuit breaking chamber, the partition wall, and the overload fusing chamber, respectively.

This heat-resistant resin molded body is made in a cylindrical or rectangular shape, and may be made of an opaque material, but it is molded so that the interior of the short-circuit breaker chamber and overload melting chamber can be viewed from the outside.

A cylindrical body made of a transparent polymer material such as acrylic resin is fitted around the outer periphery of the heat-resistant resin molded body, and a notch is provided at the side end of the cylindrical body that is attached to the short-circuit breaking chamber side. Alternatively, openings are provided and filled with arc-extinguishing powder during manufacture of the fuse body.

An embodiment of the present invention will be described below based on the drawings, but the scope of the present invention is not limited to this embodiment.

Fig. 1 is a longitudinal cross-sectional view of a sealing fuse according to the present invention, Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1, and Fig. 3 is a cross-sectional view taken along line A-A in Fig. 1. FIG. 4 is a cross-sectional view taken along the line, after the fuse conductor is housed during the manufacture of the hermetically sealed fuse according to the present invention.
FIG. 5 is a perspective view of the cylindrical body of the present invention, and FIG. 6 is a perspective view of the heat-resistant resin cylindrical body of the present invention.

In FIG. 1, a heat-resistant resin cylindrical body 1 has a short-circuit breaking chamber 2 hollowed out on the left side of the center, and an overload fusing chamber 3 hollowed out on the right side, and the boundary between the two chambers is separated by a partition wall 4.

A transparent cylinder 5 is fitted around the outer periphery of the heat-resistant resin cylinder 1, and waterproof covers 6, 6' made of weather-resistant rubber are fitted to both axial ends of the transparent cylinder 5 to make them tightly fit together.
You may simply use sealing tape or paste instead.

A connected conductor body 7 for a fuse that passes through the axial center of the heat-resistant resin cylindrical body 1 is provided with sleeves 8 and 8' at both ends for connecting the lead-in wires to the power supply side and the load, respectively, and the inner end thereof A thin metal plate 10 is attached to the connecting bodies 9 and 9' provided for the connection, and this thin plate conductor 10 is separated in the overload fusing chamber 3, and the part is an overload fusing element 11 made of a lumpy low melting point alloy. and then passes through the compartment 4 into the short-circuit breaking chamber 2, where a hole 12 is drilled in the sheet 10 to narrow the cross-sectional area and form a short-circuit breaking element.

As shown in Fig. 2, the inside of this short-circuit breaking chamber 2 is such that there is a thin plate 10 with a hole 12 in the center, around which silica sand 13 is filled as an arc-extinguishing powder, and this arc-extinguishing powder is melted by melting. Once the color changes, it can be visually recognized from the side surface 14 of the transparent cylinder 5.
The condition inside the overload fusing chamber 3 is as shown in Fig. 3.
Similarly, a transparent cylinder 5 has an overload fusing element 11 in the center.
It can be visually recognized from the side surface 14 of.

To assemble this hermetically sealed fuse, as shown in FIG.
and the right end* of the heat-resistant resin cylinder 1 with the overload welding chamber 3 opened, in the direction shown by the arrow 16 from the left end opening of the transparent cylinder 5 with the notch 15 at the upper left end as shown in FIG. As shown in Figure 4,
The transparent cylinder 5 is inserted until the left end surface 17 reaches the left side surface 18 of the short circuit breaker chamber 2.

In the state shown in FIG. 4, the transparent cylinder 5 covers all of the overload fusing chamber 3 and most of the short circuit breaking chamber 2, but a part of the latter is opened by the notch 15. In the state shown in FIG. 4, at an intermediate position during the assembly operation, silica sand is introduced and filled as an arc-extinguishing powder into the short-circuit breaking chamber 2 through this opening.

When filling with silica sand is completed, the transparent cylinder 5 is further slid to the left (not shown), and as shown in FIG. In this case, a weather-resistant adhesive such as silicone resin is used to fix the notch portion 15 sufficiently.

The hermetic fuse of the present invention has the above structure,
The short-circuit breaking room and the overload fusing room are directly visible, and connection work such as lead-in wires is done at the sleeves 8 and 8' at both ends at the work site, so the inside can be directly seen during work or inspection. ,
The burn-through of the low-melting point alloy can be seen during overload melting, and the discoloration of the arc-extinguishing powder can be seen during short-circuit breakage.

Furthermore, the sealed fuse of the present invention does not require a blowout indicator and the manufacturing process is simplified, so it is very useful for use as a fuse for protecting service lines.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of an embodiment of the sealing fuse of the present invention, Fig. 2 is a cross-sectional view taken along A-A, Fig. 3 is a cross-sectional view taken along B-B, and Fig. 4 shows its manufacturing process. edge,
A perspective view showing a state in which arc-extinguishing powder can be injected, No. 5
The figure is a perspective view of a transparent cylinder, and FIG. 6 is a perspective view of a heat-resistant resin cylinder. 2...Short circuit breaking room, 3...Overload fusing room, 5...
...Transparent cylinder, 7... Conductor body, 8... Sleeve,
9,9... Connection body, 10... Thin plate metal body, 11...
...Overload fusing element, 12...hole, 15...notch.

Claims (1)

[Claims for Utility Model Registration] A short-circuit interrupting element that is made of a thin plate, wire, etc. of a metal or alloy with a relatively high melting point and whose cross-sectional area is partially reduced so that it melts in the event of a short circuit; and the short-circuit interrupting element. An overload fusing element formed on an extension of the thin plate, wire, etc. of the element and cut at a part, and that part is connected via a fuse member such as a mass of low melting point metal, a fuse conductor connected in series to the connecting conductor through a sleeve and a connecting body at both outer ends of the fuse conductor; and a heat-resistant conductor for arc extinguishing inside the fuse conductor after accommodating a short-circuit breaking element of the fuse conductor; A short-circuit breaking chamber having a space for filling the powder and a filling inlet so that the inside can be seen from the outside, and an extra space for accommodating the overload fusing element, and having an extra space through a partition wall. a cylindrical body formed with an overload fusing chamber that is provided adjacently on the axis of the short-circuit breaking chamber and is visible from the outside; a cylindrical body, in which at least a portion for monitoring the inside thereof is transparent; and in an assembled state, connecting conductors on both outer sides of the fuse conductor wire are extended outward in the longitudinal direction of the cylindrical body, and a power source is connected to the cylindrical body; A sealed fuse intended to be connected between the load and the load.