JP2569817Y2 - Wire fuse - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric wire fuse used by connecting to a service line of a low voltage distribution line.

[0002]

2. Description of the Related Art As a wire fuse used for the purpose of protecting a drop line of a low-voltage distribution line, a current-limiting fuse having no sound and no arc at the time of interruption is used from the viewpoint of public safety or environmental harmony. Particularly in such a current-limiting type fuse, the interrupting part is formed by disposing a fuse element (wire member) in an insulating case and further filling an arc extinguishing agent such as quartz sand around the element. Was buried in the arc extinguishing agent, and it was not possible to directly visually check the interruption state.

[0003] For this purpose, a fusing display device specially made visible from outside the insulating case is provided. That is, a display line is connected in parallel to the fuse element and a display member is further attached to the same line, and after the element is cut off (fused), a current is intensively applied to this display line to glow the line, As a result, a scoring mark is formed on the display film that is in close contact with the display line, or the ignition member reacts with the glowing display line to change the color of the display member, and this state is visually checked through a transparent insulating case. Thus, the operation state of the fuse is confirmed.

[0004]

However, as described above, the conventional type wire fuse has a structure that requires a display line for indicating fusing and a display member (seal or reactant) in addition to the fuse element. There is a problem that the assembling is troublesome and the cost is increased. In addition, there is a problem that an insulated case of the insulating case may be burned due to an unfused display line after the element is blown. In order to solve this problem, a small-current fusing part and a large-current fusing part composed of a resistance wire surrounded by an arc extinguishing agent except for a part are connected in series, and these are placed in a transparent tube. Fuses are provided (see Japanese Utility Model Laid-Open No. 57-140058). However, since the exposed portion of the resistance wire is connected to the low melting point alloy of the small current fusing portion via the heat storage body, when melted, the resistance wire on the connection side partially remains, from the outside of the transparent cylinder. When observing the inside, there was a problem that the actual state of the melting was erroneously recognized due to the remaining of the resistance wire.

The present invention has been made to solve the above-mentioned problems (technical problems) of the prior art, and even if the current can be cut off in a silent or arc-free state, the cut-off is performed. The situation can be visually checked directly from outside the case, and as a result, the above-mentioned display lines and display members are originally unnecessary, so that the structure can be simplified and the cost can be reduced. It is an object of the present invention to provide an electric wire fuse capable of preventing the occurrence of the burning accident caused by the electric wire. Particularly, the wire member placed in the vacant space of the target to be visually observed has a feature that the entire region is completely melted when a large current passes because the wire member is sandwiched between the wire members that are melted by the passage of the same large current on both sides, The purpose of the present invention is to prevent the problem of false recognition as in the related art from occurring.

[0006]

In order to achieve the above object, an electric wire fuse according to the present invention comprises a fusing chamber for locating a fusing portion for overload current fusing in a fuse inside a transparent insulating case; Forming a cut-off chamber for locating a cut-off portion for cutting off a large current, and filling the cut-off chamber with an arc extinguishing agent, connecting the fusing portion and the cut-off portion in series, and connecting one end to one terminal. In the electric wire fuse, the other end of which is connected to the other terminal, the interrupting chamber is constituted by two small chambers sandwiching an empty space in the middle, and the wire member of the interrupting portion in the fuse is formed by two small chambers. Are arranged in series with each other in a vacant room provided therebetween, and the arc extinguishing agent is filled in both small rooms located on both sides of the vacant room, and in the case of interrupting a large current, The respective wire members in both chambers melt. Earlier than, the line member In the empty chamber of the intermediate in the middle of the opposite sides of the line member is obtained so as to melt.

[0007]

When a large current flows through the wire member, the interrupted portion thereof is melted and vaporized, and the large current is interrupted. In that case,
Loud sound leakage is prevented by the insulating case, and the arc is extinguished by the arc extinguishing agent. By observing the state of the cut-off part in the vacant room through the transparent insulating case,
The above-mentioned interruption state can be confirmed.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. 1 indicates a wire fuse. Numeral 2 denotes a fuse element of two elements, a cutoff section 3 and a blowout section 4. The fuse element 2 includes a blowout section 4 made of a low melting point alloy 5, cutoff sections 6a and 6a ', and a heat storage section 6b. A wire member 6 such as a copper wire or a silver wire, and an interrupting portion 3 made of an arc extinguishing agent 7 such as quartz sand filled around the wire member 6 so as to bury the wire member 6. These fusing parts 4
Low melting point alloy 5 and one end 6c of the wire member 6 of the interrupting section 3
Are connected to each other, and the cutoff section 3 and the fusing section 4 form a series circuit.

Reference numeral 8 denotes an inner cylinder made of a transparent synthetic resin, for example, a polycarbonate resin, which is partitioned and formed into cut-off chambers 8a and 8b and a fusing chamber 8c. The cut-off section 3 is housed in the cut-off chambers 8a and 8b. 4 is housed separately in a fusing chamber 8c adjacent to the shut-off chamber 8b. As shown in the figure, the above-mentioned shut-off chambers 8a and 8b are divided into two small chambers, and the space between the two shut-off chambers 8a and 8b formed in the small chamber is not particularly filled with an arc extinguishing agent. 8d is formed, and a part of the wire member 6 of the blocking portion, that is, a central blocking portion 6a 'is located in the empty room 8d.

Reference numeral 9 denotes a partition plate provided with a hole 9a for passing a wire member at the center thereof.
d. Numeral 10 denotes an outer cylinder made of the same transparent synthetic resin formed in close contact with the inner cylinder 8 so as to cover the inner cylinder 8 from the outside thereof. 12 and the end connection conductor 13 and the other end 6 e of the wire member 6. Note that a transparent insulating case 14 is formed by the two tubes, the inner tube 8 and the outer tube 10.

Reference numeral 12 denotes an electric wire connection terminal crimped to the end connection conductor 13, which is connected to the low melting point alloy 5 of the fusing portion 4 of the fuse element 2 via the conductor 13.
Reference numeral 11 denotes an electric wire connection terminal similarly crimped to the other end 6e of the wire member 6, reference numeral 15 denotes an attachment connection lead wire which is connected to one of the electric wire connection terminals 12 in advance at the time of assembly, and reference numeral 16 denotes an outer cylinder 10. The terminal cover 17 is detachably attached to the annular projection 10a at the end of the terminal.
A backlash collar made of synthetic resin or the like is inserted into the wire connection terminal so as to intervene in a gap a formed between the outer cylinder 10 and the outer cylinder 10. Reference numeral 18 denotes a silicone resin sealing material filled in the gap a. Show.

In the electric wire fuse 1 having the above-described configuration, when an overload current flows, the low melting point alloy 5 of the fusing portion 4 of the fuse element 2 is melted away and the current is cut off. In this case, the detached (open circuit) state of the low melting point alloy located in the fusing chamber 8c can be visually confirmed through the transparent insulating case 14.

On the other hand, when a large current flows as in a short circuit accident or the like, the shutoff portions 6a and 6a 'located in the shutoff chambers 8a and 8b and the vacant chamber 8d ignite and melt over their entire lengths. The gas is vaporized, and the large current is cut off. In this case, melting,
Since the vaporization is performed in the case 14, even if a sound accompanying it is generated, it is prevented from leaking out of the case.
When the shutoff portions 6a of the shutoff chambers 8a and 8b ignite as described above, the heat thereof causes the arc quenching agent 7 to emit an arc extinction gas, and the arc is instantaneously extinguished by the gas. When the interruption of the large current is performed as described above, the molten (open circuit) state of the interruption portion 6a 'substantially at the center of the wire member 6 located in the empty room 8d is visually observed from outside through the insulating case 14. You can check.

In the case of the above-mentioned large current interruption, the empty room 8d is hollow, while the interruption rooms 8a and 8b are filled with the arc-extinguishing agent 7, so that the wire member 6 located in the empty room 8d is closed. The heat of the blocking portion 6a 'is less likely to be lost when the heat is generated than in the blocking portions 6a located in the blocking chambers 8a and 8b. Therefore, vacancy 8
The melting of the blocking portion 6a 'at d is performed earlier than the melting of the blocking portion 6a in the blocking chambers 8a and 8b. as a result,
The reliability of confirmation of blocking by visually checking the state of the blocking portion 6a 'of the empty room 8d is high.

As described above, in the electric wire fuse 1, the operation state of both the fusing section 4 and the interrupting section 3 is determined by the insulating case 14.
Can be visually checked directly from the outside, so that the magnitude of the fault current that has flowed during maintenance and inspection can be estimated depending on the fusing location (part), making it possible to more accurately determine when to replace equipment such as equipment or electric wires. Can do,

[0016]

As described above, in the present invention, when a large current flows through the wire member 6 between the terminals 11 and 12,
The two interrupting portions 6a and 6a 'are melted and vaporized, so that the large current can be interrupted.

In the case of the shutoff, the case 14 can prevent the sound of melting and vaporization of the shutoff portions 6a and 6a 'from leaking to the outside by the case 14, and the arc extinguishing agent 7 in the case 14 allows one shutoff portion 6a. The arc generated there can be quickly extinguished, which has favorable effects on public safety and environmental harmony.

In addition, even when the above-mentioned interruption is performed, the situation of the other interruption portion 6a 'can be directly visually observed from the outside of the case 14 even when the silencing and the rapid elimination of the arc are performed as described above. It is possible to easily confirm from the outside of the case 14 that the blocking has been performed. In other words, while one of the cut-off portions 6a is substantially arc-free by penetrating the arc-extinguishing agent 7 in the case, the other cut-off portion 6a 'is located in the empty room 8d. As a result, the situation of the portion 6a 'is changed to Case 1.
4 There is an effect that can be visually observed directly from the outside. This has an advantage that the structure can be simplified and the cost can be reduced as compared with the conventional wire fuse of the type having the display line and the display member, because these are unnecessary.

In the related art, since the display line is electrically connected in parallel to the fuse element, heat generated by the display line after the fuse element is blown may cause a burnout of the insulating case. According to the present invention, such a display line is originally unnecessary, and there is also an effect that a burnout accident caused by the display line does not occur at all and is safe.

According to the invention of the present application, there are the above practical effects. In addition, by providing the shut-off chambers 8a and 8b on both sides of the empty room 8d, the entire length of the shut-off chamber is secured, and the shut-off performance particularly at the time of interrupting a large current is not reduced.
In addition, in the empty room 8d, both sides are large-current cut-off rooms, so that the intermediate wire member 6a 'has a characteristic that it is accurately melted prior to these. Then, the operation state at the time of interruption of the large current can be visually confirmed through the transparent insulating case. Further, when the interruption of the large current, the interruption portion 6a 'in the empty room 8d is melted and vaporized at once, and the insulation is immediately secured in this room. As a result, the cut-off portions in both cut-off chambers located on both sides of the same empty room 8d are electrically insulated by the empty room 8d. Thus, the fuse cylinder is prevented from being burned out, and the safety is enhanced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electric wire fuse.

FIG. 2 is an enlarged sectional view of a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric wire fuse 2 Fuse element 3 Breaking part 4 Fusing part 5 Low melting point alloy 6 Wire member 6a Breaking part 6a 'Breaking part 6b Heat storage part 7 Arc extinguishing agent 8 Inner cylinder 8a Breaking room 8b Breaking room 8c Blowing room 8d Empty room 10 Outside Tube 14 Insulation case

Claims (1)

(57) [Scope of request for utility model registration] 1. A fusing chamber for locating a fusing portion for overload current fusing in a fuse, and a fusing chamber for positioning a fusing portion for cutting off a large current in a fuse are formed and cut off inside a transparent insulating case. Fill the room with arc extinguishing agent,
In the electric wire fuse, wherein the fusing section and the interrupting section are connected in series, and one end is connected to one terminal and the other end is connected to the other terminal, the interrupting chamber has a hollow space in the middle. The wire member of the interrupting section in the fuse is arranged in series with each other in two small chambers and an empty room provided between them, and the arc extinguishing agent is provided in the empty room. If both small chambers located on both sides are filled and large current interruption occurs,
An electric wire fuse characterized in that a wire member in an intermediate space and located between the wire members on both sides is melted before each wire member in both small chambers is melted.