JPH07274351A - Flexible metal conduit - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a flexible metal conduit tube having a simple structure that can be effectively used even in a thermal environment. [Structure] The outer layer is made of stainless steel, and the inner layer is non-combustible or flame-retardant. The outer layer is formed by spirally winding thin stainless webs with their side edges overlapped with each other, and has an inner layer made of a non-halogen series nonflammable or flame-retardant material on the inner peripheral surface of the outer layer.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a flexible metal conduit tube,
In particular, the present invention relates to a flexible metal conduit tube in which a plurality of parallel corrugations are provided on a thin stainless steel web, and then the web is spirally wound to a desired diameter so that the side edges of the webs are overlapped.

[0002]

2. Description of the Related Art Conventionally, a plurality of corrugations which are continuous in the longitudinal direction are formed on a thin metal web, and the corrugated webs are overlapped with adjacent side edges so as to be at least double. There is known a flexible metal conduit tube which is wound in a spiral shape and compression-molded to prevent loosening (for example, Japanese Patent Laid-Open No. 51-96761). This conventional conduit has a corrugated shape that enhances the mechanical strength of a thin web, and can be wound in a spiral shape to ensure a moderate allowance for stretchability, bending, and twisting in the longitudinal direction. It can be cut into a suitable length, and since it is also excellent in heat resistance and durability, it is widely used as a protective tube for electric wires or cables indoors or outdoors. In addition, there is known a configuration in which a waterproof paper or the like is wound around the inner peripheral surface of the conduit to make the conduit water-resistant, if necessary.

[0003]

Recently, it has been proposed to use conduits of this type in yet another environment. One is the use in facilities with a thermal environment. In such a facility, protection against an unexpected fire is indispensable, and is naturally required in the field of conduits to which the present invention belongs.

An object of the present invention is to provide a flexible metal conduit tube which is suitable for use even in such a thermal environment with a simple structure.

[0005]

In order to solve the above problems, the present invention provides a non-halogen series non-halogenated material on the inner peripheral surface of a corrugated conduit formed by spirally winding thin stainless webs with their side edges overlapped. It is characterized by having an inner layer made of a non-combustible or flame-retardant material.

[0006]

In such a structure, the outer stainless layer provides rust prevention and durability, while the inner layer provides non-combustibility. The inner layer is also made of a non-halogen-based material, so that it is possible to prevent smoke hazards during a fire.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a flexible tube according to the present invention after it has been manufactured. The flexible tube 1 includes an outer layer 2 made of stainless steel and an outer layer 2
The inner layer 3 is made of a non-combustible or flame-retardant material (for example, a fibrous material such as non-combustible paper or flame-retardant paper) that constitutes the inner peripheral surface of the. The pipe manufacturing method is omitted because it is not the gist of the present invention, but the flexible pipe 1 is manufactured by the pipe manufacturing method as described in, for example, the above-mentioned Japanese Patent Laid-Open No. 51-96761. You can

The inner layer 3 is made of a non-halogen series material that does not cause a smoke hazard that may affect the human body during a fire. Such a non-halogen material does not generate a hydrogen halide gas that corrodes a metal, and is preferable for the outer layer or the use environment. The inner layer 3 is made of a strip of a thin web made of a fibrous material such as non-combustible paper or flame-retardant paper, and is formed with a plurality of corrugations continuous in the parallel longitudinal direction by the pipe making method as described above. The inner layer 3 is formed by spirally closely winding, for example, on a mandrel having a smooth outer surface so as to form a cylinder and the adjacent side edges thereof overlap each other.

On the other hand, as the outer layer 2, a thin stainless web, for example, a strip such as a thin stainless steel sheet (SAS 304) having a thickness of about 0.1 mm, is provided with corrugations extending in parallel in the longitudinal direction like the inner layer material. The corrugated web is wound spirally so as to be in close contact with the periphery of the inner layer 3 so as to form a cylindrical shape, and the web side edges are overlapped with each other so as to be at least double. Thus the inner layer 3
The spiral body having the outer layer 2 formed thereon is compression-molded so as not to be unraveled to form the two-layer flexible tube 1 as illustrated.

[0010]

EFFECTS OF THE INVENTION The flexible tube having the above-mentioned structure is resistant to stretchability in the longitudinal direction and twisting and bending around the axis, the outer layer thereof secures mechanical strength such as durability, and the inner layer is It is possible to protect the electric wires and cables passing through the inside from damage and prevent fire or smoke accidents even in the event of an unexpected fire.

[Brief description of drawings]

1A is a partially cutaway side view of a flexible metal conduit tube according to the present invention, and FIG. 1B is a partially cutaway front view thereof.

[Explanation of symbols]

 1 Flexible metal conduit 2 Outer layer 3 Inner layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takamichi Yamazaki 4-21-3 Shimomaruko, Ota-ku, Tokyo Inside Sankei Manufacturing Co., Ltd.

Claims (1)

[Claims] 1. An inner peripheral surface of a corrugated electric wire tube formed by spirally winding thin stainless webs with their side edges overlapped with each other. Flexible metal conduit.