JPH10151219A - Fire prevention device for cable connecting part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device to prevent a fire from occurring and spreading by effectively absorbing flame or high temperature/pressure gas generated from an earth fault at a connecting part of OF cables, etc. SOLUTION: This fire prevention device for a cable connecting part includes clamps 4, 4' with lids cut asunder, and troughs 2, 3. The clamps 4, 4' are firmly attached and tighten a cable at both ends of the cable connecting part. And the troughs 2, 3 made of fireproof material cut asunder are inserted between the lids of the clamps 4, 4'. The inserted troughs 2, 3 are connected to each other and cover the cable, and the clamps with lids 4, 4' are connected with a bolt 9 and a nat 10, etc. In this way, a sealed box for pressure release is formed with troughs inside inserted between the lids of the clamps. And high pressure gas and flames escaping from both ends of the sealed box are covered by a heat-resisting winding sheet which absorbs the escaping flames and gas and expands but doesn't let them out covering both ends of the sealed box and the connecting part between the cables.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing a connection of a power cable from causing a fire in the event of a ground fault and spreading its own cable and other cables. The device is particularly necessary for the connection of an OF cable containing oil in the cable, and is installed in a tunnel or a manhole.

[0002]

2. Description of the Related Art With the increasing importance of power cables, various fire prevention measures have been adopted. The worst of the fires is the ground fault, which emits large amounts of energy, causing fires and blasts to cause disaster. Especially OF cable,
Since oil is contained in the cable, a fire is likely to occur and strong measures are desired. A conventional connection is shown in FIG. The cable general portion is hermetically fixed in a trough body 105 and a lid 104 made of flame-retardant reinforced plastic. This fire prevention trough prevents the spread of a cable fire that occurs at the time of cable ground fault due to its flame retardancy and airtightness. The general part can be isolated by the trough in this way, but it is difficult to assemble the trough in the part where relatively small bends such as the rising part and the connection part 101 are connected. Wrapped on top. The connecting portion 101 is housed in a copper tube and has a large outer diameter. Further, a bent portion called an offset portion follows the connecting portion, so that measures are delayed.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a disaster prevention device that does not cause a fire to spread even when a ground fault occurs at a connection portion of an OF cable or the like and a high-temperature high-pressure gas or flame is generated. . In an OF cable line, the transmission capacity of the cable is very large, and when a ground fault occurs, a large amount of heat is released to decompose the oil, and the flame and the blast rupture the copper pipe, and from the connection to the cable side. Looming. However, it is necessary to absorb this first wave well and seal it to prevent fire.

[0004]

Therefore, as a device for protecting the connection portion of the OF cable from a fire in the event of a ground fault, the connection portion is placed in a sealed box, and the flame and blast at the time of the ground fault are determined. The flame and blast were guided into a narrow space made of heat-resistant sheet, and the oxygen was not supplied to suppress the persistence of combustion, and by expanding the sheet, the blast was reduced.

That is, in a disaster prevention device for protecting a cable connection portion from a fire in the event of a ground fault, a restraint fitting 4 with a cover plate for fastening a cable at both ends of the cable connection portion.
4 'is fixed on a cable, troughs 2 and 3 made of a refractory and heat-resistant material are inserted between the cover plates, and the troughs 2 and 3 are joined together to cover the cable. A pressure-releasing closed box in which the troughs are sandwiched by lid plates connected by nuts 9, 10 and the like is produced.

The blast accompanying the ground fault escapes from the contact portion between the lid plate and the trough end face of the restraint fittings 4 and 4 'on both sides, so that the cable connection part is protected from fire in the event of a ground fault. In the disaster prevention equipment, cover the connection part and the nearby cable with a pressure-release sealing box, wrap high-pressure gas and flame escaping from both ends with a heat-resistant sheet between both ends of the pressure-release sealing box and the cable, and remove the leaking flame and gas. A disaster prevention device characterized by being covered with a wrapping sheet that absorbs and expands in the sheet but does not go outside.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an external view of a pressure-release closed box 1. Assuming that the cable connection portion 101 has already been assembled, the connection portion is temporarily suspended, and the height of the ladder 5 is adjusted by using the receiving metal 107 that is output from the vertical hardware 106. The connection section trough main body 2 is installed on the ladder, and the cable connection section 101 is placed on the saddle 6 fixed to the trough main body 2.
The cable connection part 101 is covered with a split FRP protective pipe 7 so that the connection part copper pipe does not splash directly into the trough even if it breaks. The trough cover 3 for the connection part is put on and the band 8 is tightened together with the trough body 2. While the lid plates shown in FIG. 2 are in firm contact with each other at both ends of the trough, the restraining members 4 and 4 ′ with lid plates are fixed on the cable. The lid plates of the restraining fittings 4, 4 ′ with lid plates at both ends are connected by four connecting bolts 9 and nuts 10 so as to sandwich the troughs 2, 3. In principle, each part is divided into two parts so that they can be used in the already assembled connection part. This completes the pressure-release closed box.

FIG. 2 is an external view of the restraining fittings 4 and 4 'with a cover plate. A portion 13 for sandwiching the cable is shown, and a cable tightening bolt hole 12 is shown. The trough contact surface is 14 and the connection bolt hole is 11. For single-core cables, non-magnetic materials are required. Therefore, stainless steel and heat-resistant reinforced plastic are desirable. FIG. 3 shows a heat-resistant sheet (aramid sheet) 15 having a width of 2 m and a length of 3 m, which is wound around the pressure-relieving box 1 and the nearby cable 102, with the 2 m side being applied in the cable axial direction, and the remaining cable side of the sheet is folded. 16
It is the external view which hung. Aramid sheets are not only heat resistant but also have high strength and tear resistance, making them ideal for this application. The band 16 also used an aramid band. The aramid sheet is 0.4 mm thick and is used with a double weight.
Layered. The strength of the sheet used here is 20 kg / m
m width. In addition, the yarn of the sheet was 1000th, and a sheet of a woven fabric was used in view of the expectation that the gas would pass immediately before breaking by gas pressure.

[0009]

【The invention's effect】

1) Fix it to the cable connection using a restraining jig with a lid plate,
Next, cover with a trough made of fire-resistant heat-resistant material, fasten each other with a band, and furthermore, use a pressure-release airtight box that sandwiches both ends of the trough with a cover plate. In the event of an accident, high-pressure gas can escape from the contact section between the trough end and the cover plate. In addition, the movement of the trough by gas pressure could be solved by connecting the lid plates on both sides. 2) In a device that covers the connection part and the nearby cable with a pressure-release sealed box and allows high-pressure gas and flame to escape from a specified part, wrap the escape port with a sheet of fire-resistant and heat-resistant material, and start leaking flame and gas. He made a cone that absorbed the water and did not let it go outside, and caused a ground fault to examine the spread of the flame, but the flame did not go outside the disaster prevention equipment. That is, the oil smelled in the closed box for pressure release or in the cone, but no black oil came out to the outside. The pressure of the wound sheet was almost released after the central portion expanded. No cracks or tears occurred in the sheet. Furthermore, the bending of the cable at the offset section following the connection section does not affect the installation.

[Brief description of the drawings]

FIG. 1 is an external view of a pressure-release closed box 1 of the present invention.

FIG. 2 is a single-sided external view of restraint fittings 4, 4 ′ with a split cover plate.

FIG. 3 is an external view of a disaster prevention device in which a wrap sheet 15 is attached to a pressure-release closed box of the present invention.

FIG. 4 is an external view of a conventional connection unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sealing box for pressure relief 2 ... Trough body for connection part 3 ... Trough lid for connection part 4 ... Restriction fitting with lid plate 5 ... Ladder 6 ... · Saddle 7 · · · Protection pipe 8 · · · Band 9 · · · Connection bolt 10 · · · Nut 11 · · · Connection bolt through hole 12 · · · Tightening bolt through hole 13 · · ·・ Cable tightening part 14 ・ ・ ・ ・ Trough contact surface 15 ・ ・ ・ ・ Heat resistant sheet 16 ・ ・ ・ ・ ・ ・ Band 101 ・ ・ ・ ・ Connection part 102 ・ ・ ・ ・ Cable 103 ・ ・ ・ ・ Disaster prevention tape 104 ・ ・ ・・ Cable trough lid 105 ・ ・ ・ ・ Cable trough body 106 ・ ・ ・ ・ Vertical hardware 107 ・ ・ ・ ・ Receiving hardware

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Igarashi 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Hiroo Takizawa 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd.

Claims (2)

[Claims] In a disaster prevention device for protecting a cable connection portion from a fire in the event of a ground fault, split-type restraint fittings 4, 4 'for fastening a cable at both ends of the cable connection portion are attached and fixed on the cable. Troughs 2 and 3 made of a fire-resistant material are inserted between them and joined together to cover the cable. The restraining brackets 4 and 4 'with cover plates are connected by bolts, nuts 9 and 10, and the troughs are covered with cover plates. Sealed box for pressure release. 2. A disaster prevention device for protecting a cable connection portion from a fire in the event of a ground fault, wherein the connection portion and a nearby cable are covered with a pressure-relieving airtight box, and high-pressure gas and flame escaping from both ends are connected to both ends of the pressure-releasing airtight box. Wrap the space with a heat-resistant sheet,
Disaster prevention device characterized by being covered with a wrapping sheet that absorbs the leaking flame and gas into the sheet and expands but does not go outside.