JPH0237348Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a protective tube used for inserting a signal cable or the like into piping.

[Conventional technology]

In various plants such as nuclear reactors, when a sensor or the like is inserted into piping, the above-mentioned protection tube is used to facilitate the insertion and protect the cable connected to the sensor or the like.

As shown in Fig. 3, this type of conventional protection tube uses a so-called flexible tube 1, which is a tube with fine folds and can be expanded and contracted, and a sensor (not shown) etc. is attached to the tip of the tube. Cable 2, etc. is passed through it. This flexible tube 1 can be bent along various curves because each part can expand and contract freely, so it can be inserted while being pushed into a curved pipe 3, as shown in Fig. 3. can do.

[Problem that the invention attempts to solve]

However, when pulling out the protective tube that has been pushed into the pipe 3, if there is strong resistance due to friction at the corners of the pipe 3, etc., the flexible tube 1 described above will stretch beyond its limit. Sometimes. If this happens, the original flexibility of the flexible tube 1 will be lost and it will no longer be able to bend freely. As a result, the flexible tube 1 is strongly pressed against the wall surface of the piping 3, and the frictional resistance with the wall surface becomes even stronger, making it difficult to pull out. If you try to forcefully pull it out in this state, problems such as wire breakage and peeling of the coating may occur.

In order to solve this problem, as shown in Figure 4, a flexible cable 4 with low elongation, such as a wire, is passed through the flexible tube 1 to reduce the elongation of the flexible tube when it is pulled out. Attempts were made to regulate it. However, in reality, when the corner of the pipe 3 is tight (when the curvature of the corner is large), the flexible tube 1 is sandwiched between the stretched cable 4 and the pipe 3. It was found that the friction became stronger and it became even more difficult to pull out.

This invention was made to solve the above-mentioned problems with conventional protection tubes, and aims to provide a protection tube for cable insertion that can be easily pulled out from curved piping.

[Means and examples for solving the problem]

Hereinafter, the configuration of this invention will be explained in detail based on illustrated embodiments.

The protective tube for cable insertion according to this invention connects short flexible tubes 11, 11... with space for passing cables 12, etc., to joints 15, 15.
..., pass the cable 14 through these flexible tubes 11, and connect it to the joint 1.
5, 15... are connected.

The length of one section of the flexible tube 11 between the two joints 15 and 15 is the same as the length of the pipe 13 to be inserted.
It varies depending on the depth of the corner, the number of corners, their curvature, the smoothness of the inside, etc., but in general, if the curvature of the corner is large, it is necessary to shorten it, and conversely, if the curvature is small, it can be lengthened.

The cables 14, 14, . . . are made of wire or other material that is strong, easy to bend, and has less elongation than the flexible tube 11. This cable 1
The length of one section of the flexible tube 11 is made sufficiently shorter than the maximum elongation length of one section of the flexible tube 11.

Note that the cable 12 and the like pass through the joints 15, 15, . . . and into the flexible tubes 11, 11. In this case, the cable 12 may be arranged in the flexible tubes 11, 11 side by side with the cables 14, 14, etc., as shown in FIG. 1, or the cable 12 may be arranged by being wound around the cables 14, 14... can.

[Effect]

When this protection tube is inserted into the piping 13,
Even if the pipe 13 has a corner, the flexible tube 11 is pushed forward while bending along the corner. This point is the same as using a general flexible tube.

On the other hand, when pulling out this protection tube from the piping 13, as shown in FIG. 2, the cables 14, 14...
flexible tube 11 in each section,
Since the tubes 11, 11... are restricted from elongating beyond the limit, the tubes 11, 11... will not be stretched too tightly. Moreover, since the cables 14, 14... are supported by the joints 15, 15... in short sections, the flexible tubes 11, 11... are not pinched between the corners of the pipe 13 and the wall surface. .

[Effect of idea]

As described above, according to this invention, when the protective tube is pulled out from the bent pipe 13, the flexible tubes 11, 11... are prevented from elongating beyond their limits, and the wall surface of the pipe 13 and the cables are The flexible tubes 11, 11... are not pinched between the flexible tubes 14, 14.... Therefore,
The flexible tubes 11, 11, . . . can be easily pulled out without experiencing high frictional resistance with the inner wall of the pipe 13 while maintaining a flexible state in which they can be bent freely.

[Brief explanation of the drawing]

Fig. 1 is a half-sectional perspective view of a protection tube for cable insertion showing an embodiment of this invention, Fig. 2 is an explanatory diagram of the state of use of the protection tube, and Figs. 3 and 4 are illustrations of a conventional protection tube. It is an explanatory diagram of a usage state. 11...Flexible tube, 14...,
Cable, 15...joint.

Claims (1)

[Scope of utility model registration request] In a protective tube for cable insertion consisting of a flexible tube with a space for the cable to pass through, short flexible tubes are successively connected through joints, and in these flexible tubes there is a tube whose length is shorter than the maximum extension length of the tube. A protective tube for inserting a cable, characterized in that a cable having a smaller elongation than that of the tube is passed through, and the cable is connected to substantially the center of the joint.