JP2003269661A - Flexible tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent corrosion of a metal corrugate tube even if rain water intrudes and retains in an annular clearance between a protective tube and the metal corrugate tube in a flexible tube formed by covering the outer circumference of the metal corrugate tube with the synthetic resin protective tube. <P>SOLUTION: This flexible tube 4 is formed by covering the outer circumference of the metal corrugate tube, which is constituted by axially forming circumferential projecting streaks 1, etc., at prescribed pitch intervals in the circumferential wall of the thin metal tube, with the synthetic resin protective tube 3. An anticorrosion layer 10 is formed on the outer circumference of the metal corrugate tube 2. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flexible tube.

[0002]

2. Description of the Related Art For example, as a pipe used for gas piping, as shown in FIG. 2, a metal formed by forming circumferential ridges 1 ... On a peripheral wall of a thin metal pipe at a constant pitch in the axial direction. A flexible tube 4 is widely used in which a synthetic resin tube 3 is externally fitted to the outer circumference of a corrugated tube 2 made of plastic.

Since the flexible tube 4 is reinforced by the circumferential ridges 1 ... of the corrugated tube 2 inside, there is no fear of flattening the tube due to load application, and the outer circumference is the tube 3 made of synthetic resin. Since it is covered, it has the advantage of reliably protecting the internal metal pipe from a corrosive environment.Furthermore, even if it is freely bent along the gas pipeline, the pipe section of the bent part does not deform flatly It has various advantages such as easy construction.

[0004]

By the way, in general, the domestic piping work for gas pipes depends on the procedure of connecting from the public trunk pipe line to each domestic pipe line through the branch pipes, but as shown in FIG. Piping work for domestic piping 5 and this domestic piping 5
Since the work for connecting the gas appliance 6 installed inside the house is generally performed separately, the domestic pipe 5 is left as it is until the gas appliance 6 is connected after the domestic pipe 5 is laid. It is often done. In addition, reference numeral 7 in the drawing
Indicates a gas meter.

By the way, the above flexible tube 4
There is a one-touch joint that can be joined by simply inserting it when connecting to the gas appliance 6 (for example, Japanese Patent Laid-Open No. 2000-27473).

This flexible tube joint 11 is
As shown in FIG. 4, it comprises a tubular body 12, a push ring 13 whose tip is screwed into the tubular body, and a retainer 14 interposed between the tip of the push ring and the inside of the tubular body. The flexible tube 4 having the corrugated tube 2 exposed at the tip for the length of several ridges is inserted from the push ring 13 into the tubular body 12, and at this time, the flexible tube 4 is passed over the retainer 14 and the tubular body 12 is moved to the uppermost position. Corrugate tube 2 inserted all the way
The retainer 14 is engaged with the ridges to prevent the retainer 14 from slipping out, and at the same time, the outer circumference of the corrugated tube 2 is sealed with the elastic packing 15 and the fireproof packing 16, and the outer circumference of the synthetic resin tube 3 is preliminarily set inside. The flexible tube can be hermetically connected by sealing with the inserted rubber ring 17.

In order to connect the flexible tube 4 to such a joint 11, as described above, the outer layer synthetic resin tube 3 is removed, and the inner corrugated tube 2 is provided by the predetermined number of ridges. It needs to be exposed and this is usually done during plumbing.

That is, as shown in the partially enlarged view of FIG. 3, the synthetic resin tube 3 is cut off from the end of the tube, and the projections 1 ... To be done.

At this time, if the corrugated pipe is left uncovered thereafter, rainwater or the like may flow into the corrugated pipe, and such inflow of rainwater may cause a failure in gas supply. The cap 8 is put on the exposed pipe end of the corrugated pipe 2 shown in the partially enlarged view of FIG. 2. Even if rainwater is prevented from flowing into the corrugated pipe 2, the synthetic resin tube 3 and the metal corrugated pipe 2 are prevented. Rainwater may permeate and accumulate in the annular gap 9 between the and.
When the flexible tube 4 is connected to the gas appliance 6, the connecting portion is generally slackened in a U shape as shown in FIG. 4, but as described above, the synthetic resin tube 3 and the corrugated tube 2 are used. There was a problem that rainwater that invaded during the period was concentrated on the lowermost portion 4U of the U-shaped portion, and the metal corrugated pipe 2 could be corroded from the outside by the rainwater within a long period of time.

The present invention solves the above problems and ensures that even if rainwater permeates and accumulates in the annular gap between the synthetic resin tube and the metal corrugated pipe, the metal corrugated pipe will not corrode. It was made as an issue to prevent it.

[0011]

In order to solve the above-mentioned problems, a flexible tube according to a first aspect of the present invention is a metal corrugated body in which circumferential projections are formed on a peripheral wall of a thin metal tube at regular intervals in the axial direction. In a flexible tube formed by fitting a synthetic resin tube on the outer circumference of the tube, a corrosion protection layer is formed on the outer circumference of the metal corrugated tube.

Therefore, even if rainwater or the like enters between the metal corrugated tube and the synthetic resin tube, the two colors of the metal corrugated tube are prevented by the anticorrosion layer, and it can be safely used for a long period of time. Become.

As the anticorrosion layer, there is a layer formed by applying a water resistant coating or a water repellent. According to a second aspect of the present invention, the anticorrosion layer of the flexible tube of the first aspect is a corrosion-resistant oxide film formed by subjecting an outer surface of a metal corrugated tube to a surface treatment.

In this case, since the oxide film is extremely strong against corrosion, it is suitable as an anticorrosion layer. In this case, there is no need to provide an anticorrosion layer by painting.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a flexible tube which is an embodiment of the present invention will be described. FIG. 1 is an enlarged cross-sectional view of a main part of a flexible tube.

In FIG. 1, the metal corrugated tube 2 is the same as the conventional one, but the anticorrosion layer 10 is formed on the surface thereof. And this flexible tube 4
First, mold the metal corrugated tube 2 from a thin metal tube,
Next, the anticorrosion layer 10 is formed on the outer circumference of the corrugated tube 2, and after the anticorrosion layer 10 is formed, the tube 3 made of synthetic resin is externally fitted on the outer circumference of the metal corrugated tube 2.

The anticorrosion layer 10 has a layer thickness of 10 to 30.
An epoxy resin coating layer and a water repellent coating layer having a thickness of about μm are formed, and after the coating films are dried, the synthetic resin tube 3 is externally fitted.

The anticorrosion layer 10 is applied by a usual coating means such as spray coating or dipping of paint or water repellent. Also, when a thermosetting resin coating is used as the anticorrosion layer, when the metal corrugated pipe is cooled after annealing, if the resin coating is applied using the residual heat, no heat of air is needed for heating. It is possible to produce economically.

Further, a corrosion resistant oxide film may be formed on the metal corrugated tube 2 as an anticorrosion layer. In this case, surface treatment is performed at the stage of molding the metal corrugated tube 2 to form an oxide film on the surface.

Therefore, the flexible tube 4 is
Outer layer synthetic resin tube 3 and inner corrugated tube 2
Even if rainwater or the like enters the gap 9 between the outer peripheries, it is not corroded by these.

[0021]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, rainwater and the like enter and accumulate in the annular space between the inner surface of the tube made of synthetic resin and the outer surface of the metal corrugated tube until it is connected to the gas appliance. Even if they do, since they are prevented from directly touching the surface of the metal corrugated pipe by the anticorrosion layer, even if they are piped in a U shape as shown in FIG. It will not be corroded by rainwater.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a flexible tube according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional flexible tube.

FIG. 3 is an explanatory diagram showing a gas pipe.

FIG. 4 is an explanatory sectional view of a connection joint of a flexible tube.

FIG. 5 is an explanatory diagram showing a state in which a flexible tube is connected to a gas appliance.

[Explanation of symbols]

1 ridge 2 Metal corrugated pipe 3 Synthetic resin tubes 4 flexible tube 5 Home plumbing 6 gas appliances 7 gas meter 8 caps 9 annular gap 10 Anticorrosion layer

Claims (2)

[Claims] 1. A flexible tube in which a synthetic resin tube covers the outer circumference of a metal corrugated tube in which circumferential projections are formed on a circumferential wall of a thin metal tube at regular intervals in the axial direction, A flexible tube having an anticorrosion layer formed on the outer periphery of the metal corrugated tube. 2. The flexible tube according to claim 1, wherein the anticorrosion layer on the outer circumference of the metal corrugated tube is a corrosion-resistant oxide film formed by subjecting the outer surface of the metal corrugated tube to a surface treatment.