JP2008079437A - Freezing failure preventing communication cable pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a freezing failure preventing communication cable pipe which is excellent in freezing failure prevention effect, allows a communication cable such as an optical fiber cable to be inserted easily and enables the freezing failure prevention function to be exchanged easily. <P>SOLUTION: A freezing failure prevention pipe 3 is formed of a volume expansion absorption material layer 4 and flexible pipes 5 which are laminated on the inner and outer faces of the volume expansion absorption material layer 4 and whose outer and inner faces are substantially smooth. The freezing failure prevention pipe 3 is inserted into an outer pipe object 2 to obtain a freezing failure prevention communication cable pipe. When a freezing failure occurs, the freezing failure prevention pipe 3 is pulled out and a new freezing failure prevention pipe 3 is inserted for exchange. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication cable pipe for preventing freezing failure in which a communication cable such as an optical cable attached in a communication cable pipe buried underground is not damaged when water entering the pipe is frozen.

  Conventionally, when a communication cable such as an optical fiber cable is buried in the ground, to protect the communication cable, a communication cable pipe is buried and the communication cable is inserted into the communication cable pipe. It was inevitable that water entered the communication cable pipe.

  As shown in FIG. 8, the communication cable has a branch pipe 21 connected to the communication cable pipe 20, its tip exposed to the ground surface, and the communication cable is taken out from the end and connected to each household. . That is, the branch pipe 21 includes a small diameter communication cable pipe 22, a bend pipe 23 connected to the tip of the small diameter communication cable pipe 22, and a rise pipe 24 connected to the tip of the bend pipe 23. The end 24a of 24 is exposed to the ground surface, and the communication cable is taken out from the end 24a. In this case, since the end 24a of the rising pipe 24 is exposed to the ground surface, it is inevitable that condensation occurs inside or unknown water enters and the water is accumulated in the branch pipe 21.

  In the vicinity of the ground surface in a cold region, the water that has entered the interior freezes and expands due to the cold air that enters through the end 24a of the rising pipe 24 exposed on the ground surface, and the frozen ice presses the communication cable. As a result, there is a problem that the communication characteristics are deteriorated or the communication cable tube is destroyed. Such freezing of the intruding water depends on the temperature, but is buried in a shallow position and easily affected by cold air, for example, a connecting portion between the rising pipe 24 and the bend pipe 23 and the small-diameter communication cable pipe 22. It occurs remarkably in the range up to the vicinity.

  Various proposals have been made to solve such problems. For example, a method of inserting an optical fiber cable with a freezing prevention pipe, which is bundled with a binder and integrated with an optical fiber cable, into a communication cable line (for example, see Patent Document 1), a pipe There has been proposed a method of inserting a freeze-fault preventing pipe having at least one cable insertion tube inside the communication cable tube (for example, see Patent Document 2).

On the other hand, in the water pipe, in order to prevent destruction of the water pipe due to water freezing, it has been proposed to laminate an expansion absorption layer in the water pipe. For example, a sponge-like synthetic rubber or a synthetic resin film having closed cells that elastically change in volume is adhered to the inner periphery of a synthetic resin pipe, and the water supply absorbs the expansion of the volume when the water inside is frozen. A pipe (for example, refer to Patent Document 3) or a liquid pipe for storing a liquid that freezes due to a temperature drop, and is disposed on a pipe main body for storing the liquid and an inner peripheral surface of the pipe main body. An expansion absorbing layer as an inner lining layer made of a material that absorbs the volume expansion of the liquid by reducing the volume by being crushed according to the volume expansion of the liquid accompanying freezing of the liquid; There has been proposed a freeze breakage prevention type liquid tube (see, for example, Patent Document 4).
Japanese Patent Laid-Open No. 6-18721 Japanese Patent Application Laid-Open No. 5-276661 Japanese Utility Model Publication No. 63-126465 JP 2003-254629 A

  However, in the inventions described in Patent Documents 1 and 2, since a freeze-fault prevention pipe is provided in addition to a communication cable such as an optical fiber cable, there is a drawback that it becomes difficult to insert the communication cable and the cost is increased. there were. In particular, it was difficult to pass through a branch pipe having a small pipe diameter.

  Furthermore, when the water pipe described in Patent Documents 3 and 4 is used as a communication cable pipe, the expansion absorbing layer on the inner surface is a flexible layer, so resistance is generated when inserting a communication cable such as an optical cable, making insertion difficult. In addition, the expansion absorption layer is damaged by the communication tool such as an optical cable or a metal communication cable at the time of insertion, resulting in a decrease in expansion absorption performance.

  The present invention has been made in view of such problems of the prior art, has an excellent anti-freezing effect, allows easy insertion of a communication cable such as an optical fiber cable, and has a simple anti-freezing function. The present invention provides a communication cable pipe for preventing freezing failure that can be replaced with a new one.

  The communication cable pipe for preventing freezing failure according to claim 1 is laminated on the inner side of the outer tubular body on the volume expansion absorbing material layer, and on the inner surface and the outer surface of the volume expansion absorbing material layer, respectively. A freezing failure prevention pipe comprising a smooth flexible pipe is inserted.

  As the outer tube, any tube conventionally used as a communication cable tube such as an optical fiber cable can be used. For example, a thermoplastic resin tube such as a vinyl chloride resin, a polyethylene resin, or a polypropylene resin, a metal tube Moreover, the shape is not specifically limited, either, for example, a straight pipe, a curved pipe bent at an angle of 30 degrees, 60 degrees, 90 degrees, or the like. In particular, vinyl chloride resin is preferable from the viewpoint of flame retardancy and secondary workability of bending.

  Any material can be used as the volume expansion absorbing material layer constituting the freeze-fault prevention tube as long as it can absorb the increased volume due to freezing of water, but it is excellent in water resistance, shape recoverability, etc. Materials such as polyethylene resin, polypropylene resin, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-hexene-1 copolymer, ethylene-vinyl acetate resin copolymer, polystyrene resin, styrene -A foam having closed cells of a thermoplastic resin such as isoprene-styrene copolymer, vinyl chloride resin, rubber or the like is preferable, and a polyethylene resin foam having closed cells is particularly preferable.

  In addition, the expansion ratio of the thermoplastic resin foam becomes harder when it becomes smaller, and the volume expansion absorption performance decreases, and when it increases, the volume expansion absorption performance improves, but the mechanical strength decreases, so 20 to 50 times is preferable, and more preferable. Is 25 to 40 times.

  The thickness of the volume expansion absorbent material layer is not particularly limited, but when the deformation rate (compression ratio) of the volume expansion absorbent material layer when water freezes increases, the shape restoration property decreases, Since the shape of the volume expansion absorbent material layer is difficult to be restored even when thawed, it is preferable that the deformation rate (compression ratio) of the volume expansion absorbent material layer when water is frozen is designed to be 50% or less. .

  The flexible tube constituting the freezing failure prevention tube is not particularly limited as long as it is a flexible tube that can transmit the volume expansion when water is frozen to the volume expansion absorbing material layer. Examples thereof include thermoplastic resin tubes such as vinyl chloride resin, polyethylene resin, and polypropylene resin. In particular, polyethylene resin is preferable from the viewpoint of recyclability and cost.

  Moreover, it is preferable that the outer surface and inner surface of a flexible tube are substantially smooth surfaces. In other words, by laminating the flexible tube on the outer surface of the volume expansion absorbing material layer, the outer surface serving as the contact surface with the outer tube body and the inner surface serving as the contact surface with the volume expansion absorbing material layer become a smooth surface, resulting in freezing failure. When replacing the prevention tube, the resistance to the outer tube body can be reduced, and the volume expansion absorbing material layer can be prevented from being damaged. Further, by laminating the flexible tube on the inner surface of the volume expansion absorbing material layer, the outer surface serving as the contact surface with the volume expansion absorbing material layer and the inner surface serving as the contact surface with the communication cable become smooth surfaces, thereby absorbing the volume expansion. The material layer can be prevented from being damaged, and the insertion resistance can be reduced when the communication cable is drawn.

  According to such a communication cable pipe for preventing freezing failure, even if the water that has entered the pipe freezes, the volume expansion due to freezing can be absorbed by the volume expansion absorbing material layer through the flexible pipe. The cable is pressed and the communication characteristics are not deteriorated, and the communication cable tube is not destroyed, and the effect of preventing freezing failure is excellent.

  Moreover, the inner surface of the communication cable tube for preventing freezing failure is made of a substantially smooth flexible tube, so it has excellent sliding characteristics, and it is easy to insert a communication cable such as an optical cable. In both cases, a large number of communication cables can be inserted, and even a small-diameter branch pipe can be easily inserted.

  Furthermore, the communication cable tube for preventing freezing failure is formed by inserting a freezing failure preventing tube formed by sequentially laminating a flexible tube, a volume expansion absorbing material layer and a flexible tube inside the outer tube body. In the unlikely event that a communication failure occurs, it is assumed that the freeze failure prevention function of the freeze failure prevention tube has been impaired. Thus, the freeze-fault prevention tube can be easily replaced.

  Note that when forming communication cable conduits, it is not necessary to form all communication cable pipes for freezing failure prevention, and it is only necessary to use freezing failure prevention communication cable pipes for parts where water may freeze. For the portion where the water is not frozen by being buried at a depth higher than the freezing depth, a conventionally used communication cable tube may be used.

  The communication cable pipe for preventing freezing failure according to claim 2 is laminated on the inside of the outer tube body on the volume expansion absorbing material layer, and on the inner surface and the outer surface of the volume expansion absorbing material layer, respectively, and the outer surface and the inner surface are substantially formed. The freezing failure prevention pipe | tube which consists of a smooth flexible pipe and in which the notch part was formed along the pipe-axis direction is penetrated.

  The outer tube, the volume expansion absorbing material layer and the flexible tube in the present invention are the same as the outer tube, the volume expansion absorbing material layer and the flexible tube constituting the communication cable tube for preventing freezing failure according to claim 1. Therefore, explanation is omitted.

  The opening width of the notch formed in the freeze-fault prevention tube is formed such that a communication cable such as an optical fiber cable can be inserted. When the opening width is increased, the communication cable can be easily inserted, but the opportunity for the communication cable to drop into the notch is increased accordingly. When the communication cable falls into the notch, the communication cable comes into contact with the notch and is damaged or becomes an insertion resistance.

  According to such a communication cable pipe for preventing freezing failure, even if the water that has entered the pipe freezes, the volume expansion due to freezing can be absorbed by the volume expansion absorbing material layer through the flexible pipe. The cable is pressed and the communication characteristics are not deteriorated, and the communication cable tube is not destroyed, and the effect of preventing freezing failure is excellent.

  Moreover, the inner surface of the communication cable tube for preventing freezing failure is made of a substantially smooth flexible tube, so it has excellent sliding characteristics, and it is easy to insert a communication cable such as an optical cable. In both cases, a large number of communication cables can be inserted, and even a small-diameter branch pipe can be easily inserted.

  Furthermore, the communication cable tube for preventing freezing failure is formed by inserting a freezing failure preventing tube formed by sequentially laminating a flexible tube, a volume expansion absorbing material layer and a flexible tube inside the outer tube body. In the unlikely event that a communication failure occurs, assume that the freeze-fault prevention function of the freeze-fault prevention tube is impaired, pull out the freeze-fault prevention tube from the outer tube, and insert a new freeze-fault prevention tube into the outer tube. Thus, the freeze-fault prevention tube can be easily replaced.

  At this time, pull out the communication cable from the outer tube while pulling out the communication cable from the anti-freezing tube through the notch, or remove the anti-freezing tube while pushing the communication cable inside the anti-freezing tube through the notch. Because it can be inserted into the pipe body, it is possible to replace the freeze-fault prevention pipe regardless of the presence or absence of the communication cable, greatly reducing preparation work such as removing the communication cable or forming a separate bypass circuit. can do.

  Note that when forming communication cable conduits, it is not necessary to form all communication cable pipes for freezing failure prevention, and it is only necessary to use freezing failure prevention communication cable pipes for parts where water may freeze. For the portion where the water is not frozen by being buried at a depth higher than the freezing depth, a conventionally used communication cable tube may be used.

  The communication cable tube for preventing freezing failure according to claim 3 is laminated on the inner side of the outer tubular body on the volume expansion absorbing material layer having a semi-cylindrical cross section, and on the inner surface and the outer surface of the volume expansion absorbing material layer, respectively. A freezing failure prevention tube formed in a substantially cylindrical shape by a pair of semi-cylindrical laminates having a substantially smooth inner surface and a pair of semi-cylindrical cross sections is inserted. Is.

  The outer tube, the volume expansion absorbing material layer and the flexible tube in the present invention are the same as the outer tube, the volume expansion absorbing material layer and the flexible tube constituting the communication cable tube for preventing freezing failure according to claim 1. Therefore, explanation is omitted.

  According to such a communication cable pipe for preventing freezing failure, even if the water that has entered the pipe freezes, the volume expansion due to freezing can be absorbed by the volume expansion absorbing material layer through the flexible pipe. The cable is pressed and the communication characteristics are not deteriorated, and the communication cable tube is not destroyed, and the effect of preventing freezing failure is excellent.

  Moreover, the inner surface of the communication cable tube for preventing freezing failure is made of a substantially smooth flexible tube, so it has excellent sliding characteristics, and it is easy to insert a communication cable such as an optical cable. In both cases, a large number of communication cables can be inserted, and even a small-diameter branch pipe can be easily inserted.

  Furthermore, the communication cable tube for preventing freezing failure is formed by inserting a freezing failure preventing tube formed by sequentially laminating a flexible tube, a volume expansion absorbing material layer and a flexible tube inside the outer tube body. In the unlikely event that a communication failure occurs, the freeze failure prevention function of the freeze failure prevention tube is assumed to be impaired. Thus, the freeze-fault prevention tube can be easily replaced.

  At this time, the freezing failure prevention pipes made of a pair of laminated bodies are pulled out from the outer pipe body while being separated into the respective laminated bodies, or the facing open ends are butted together so that the communication cable is sandwiched between the pair of laminated bodies. Can be inserted into the outer tube while forming a freezing failure prevention tube, so it is possible to replace the freezing failure prevention tube regardless of the presence or absence of the communication cable, and remove the communication cable or install a separate bypass circuit. Preparation work such as forming can be greatly reduced.

  Note that when forming communication cable conduits, it is not necessary to form all communication cable pipes for freezing failure prevention, and it is only necessary to use freezing failure prevention communication cable pipes for parts where water may freeze. For the portion where the water is not frozen by being buried at a depth higher than the freezing depth, a conventionally used communication cable tube may be used.

  In the present invention, the flexible tube has a fitting portion that is bifurcated on one side edge and is provided with a retaining portion facing the opening end edge, and the other side edge has a fitting portion inside the fitting portion. A belt-shaped synthetic resin profile having a locking portion that is slidably fitted into and locked to the wire is spirally wound, and the fitting portion and the locking portion that are adjacent to each other in the wound state are fitted. And is preferably formed in a cylindrical shape. By adopting such a flexible tube, the locking portion can be expanded and contracted by sliding in the tube axis direction in the fitting portion, and the locking portion can be expanded and bent in the fitting portion. The tube diameter can be freely changed by sliding in the circumferential direction. Therefore, even when a freeze-fault prevention pipe is inserted inside a bend pipe with a small radius of curvature, a freezing fault can occur without causing wrinkles or buckling or large bending resistance in the bent part of the vent pipe. The prevention tube can be easily inserted. Even when a communication cable is pulled into the freeze failure prevention tube inserted into the vent tube, the inner surface of the freeze failure prevention tube, i.e., the inner surface of the flexible tube, substantially extends along the radius of curvature of the vent tube. Since the surface is smooth, the communication cable can be pulled in without generating a large frictional resistance.

  Therefore, it is possible to insert a freeze-fault prevention pipe into a bend pipe with a small radius of curvature without hindrance, making it possible to embed a freeze-fault prevention communication cable pipe at a shallow depth, reducing construction restrictions. And cost can be reduced.

  In the invention according to claim 2, the cutout portion formed in the freeze-fault prevention tube is shielded by a cover plate made of rubber or the like provided so as to be openable and closable across the inner peripheral surface of the opposed opening end. Opposite opening edge portions of the flexible tube are respectively covered with a cover made of rubber or the like, and the outer flexible tube is more than the notch portion of the inner flexible tube so that the volume expansion absorbing material layer is exposed. It is preferable to cut out over a large area.

  When the communication cable is pulled in by the cover plate, the communication cable can be prevented from entering the notch and being damaged at the opening edge of the flexible tube, and the communication cable can be pulled out from the freeze failure prevention tube through the notch, or This is because the communication cable can be prevented from being damaged at the opening edge of the flexible tube when the communication cable is pushed into the freeze-fault prevention tube through the notch.

  When the thickness and hardness of the cover plate are large, the cover plate can hold the communication cable so as not to enter the notch, but it is difficult to replace the freeze failure prevention tube, so the thickness is about 2 mm, The hardness is preferably about 50.

  In the invention according to claim 3, a cover plate made of rubber or the like that is in contact with the inner peripheral surface of the open end of the other laminated body facing each other is provided on the inner peripheral surface of one open end of each laminated body. It is preferable that one open end edge of the inner flexible tube is covered with a cover made of rubber or the like.

  This is because the cover plate can prevent the communication cable from entering between the opposed open ends of the pair of laminated bodies and being damaged at the open end edge of the flexible tube when the communication cable is drawn.

  According to the present invention, the effect of preventing freezing failure is excellent, the insertion of a communication cable such as an optical fiber cable is easy, and the freezing failure preventing function can be easily replaced.

  1 to 3 show an embodiment of a communication cable pipe 1 for preventing freezing failure according to the present invention.

  This freeze failure prevention communication cable tube 1 includes an outer tube body 2 made of vinyl chloride resin having an outer diameter of 96 mm and an inner diameter of 83 mm, and a freeze failure prevention tube having an outer diameter of 78 mm and an inner diameter of 54 mm inserted inside the outer tube body 2. The freeze failure prevention tube 3 is composed of a polyethylene resin foam having a closed cell (product name “Softlon S”, manufactured by Sekisui Chemical Co., Ltd., with a foaming ratio of 30 times) and a volume expansion absorbing material layer having a thickness of 5 mm. 4, flexible tubes 5 (manufactured by Tigers Polymer Co., Ltd., trade name “Taiflex Hose”) are respectively laminated on the inner peripheral surface side and the outer peripheral surface side.

  As shown in detail in FIG. 3, the flexible tube 5 has a fitting portion 52 that is bifurcated on one side edge and provided with a retaining portion 52 a facing the inner edge of the opening end. A strip-shaped synthetic resin profile 51 having a locking portion 53 that is slidably fitted into and locked in the fitting portion 52 is spirally wound on the side edge and is adjacent to each other in the wound state. The fitting portion 52 and the locking portion 53 are fitted to each other and formed into a cylindrical shape. Such a flexible tube 5 has elasticity and flexibility. That is, the flexible tube 5 can be expanded and contracted or bent by sliding the locking portion 53 in the axial direction of the tube in the fitting portion 52. The tube diameter can be freely changed by sliding the tube in the circumferential direction.

  The flexible tube 5 has substantially smooth inner and outer surfaces and is laminated on the outer surface of the volume expansion absorbent material layer 4 to prevent the volume expansion absorbent material layer 4 from being damaged, and the outer tube body. The insertion resistance with respect to 2 can be reduced. In addition, the flexible tube 5 is laminated on the inner surface of the volume expansion absorbing material layer 4 to prevent the volume expansion absorbing material layer 4 from being damaged and does not cause any trouble when the communication cable is drawn.

  The freezing failure prevention communication cable tube 1 configured as described above is frozen in the volume expansion absorbing material layer 4 through the flexible tube 5 even if the unknown water that has entered freezes and the volume expands in a cold region. Therefore, the communication cable is compressed and the communication characteristics are not deteriorated, and the outer tube body 2 is not destroyed.

  Further, since the substantially smooth flexible tube 5 is laminated on the inner surface of the communication cable tube 1 for preventing freezing failure, it is easy to insert a communication cable such as an optical cable, and a larger diameter tube is not used. In many cases, a large number of communication cables such as optical cables can be inserted, and even a small-diameter branch pipe can be easily inserted.

  Furthermore, in the unlikely event that a communication failure occurs and it is determined that the freeze failure prevention function of the freeze failure prevention tube 3 is impaired, the necessary freeze failure prevention tube 3 is removed from the outer tube 2 after the communication cable is removed. By pulling out, a new freezing failure prevention tube 3 can be inserted into the outer tube body 2 and easily replaced. Thereafter, the communication cable may be inserted into the freeze failure prevention pipe 3.

  At this time, since the smooth flexible tube 5 is laminated on the outer surface of the freezing failure prevention tube 3, the contact resistance with respect to the outer tube body 2 is small and can be easily inserted.

  In addition, when replacing the freeze-fault prevention tube 3, it is assumed that a separate bypass circuit is formed prior to removal of the communication cable so that the user's communication is not interrupted.

  Moreover, such a communication cable pipe 1 for preventing freezing failure can be suitably used when the embedding depth is reduced. For example, as shown in FIG. 4, one end of the rising pipe 6 is connected to a receiving port 71 of a bend pipe 7 having a radius of 0.3 m, while a small-diameter communication cable pipe (not shown) is inserted into an insertion port 72 of the bend pipe 7. When the freezing failure prevention tube 3 is inserted from the opening end of the rising tube 6 to the insertion port 72 of the bend tube 7 corresponding to the freezing depth, the flexible tube 5 is connected to the bent portion of the bend tube 7. Since the tube can be stretched in the tube axis direction without causing wrinkles, and only a small resistance against bending is generated, the tip of the freeze failure prevention tube 3 reaches the outlet 72 of the bend tube 7. Can be smoothly inserted. Further, since the inner surface of the flexible tube 5 is substantially smooth and does not generate wrinkles along the curved portion of the bend tube 7, the inner surface of the flexible tube 5 receives a large resistance when a communication cable such as an optical fiber cable is drawn. Absent.

  A sealing material 8 is provided at the receiving port 71 of the bend pipe 7, and a rubber stopper 9 having a right-angled triangular cross section is bonded to the inner peripheral surface of the opening end of the insertion port 72. While the riser pipe 6 is sealed via the material 8, the tip of the freeze failure prevention pipe 3 is locked via the rubber stopper 9 to prevent further intrusion, and due to a step with the freeze failure prevention pipe 3. It prevents interference when the communication cable is pulled in.

  For this reason, it becomes possible to embed the communication cable pipe 1 for preventing freezing failure at a depth of about 60 cm from the ground surface, and the burial cost can be reduced, and the burial depth can be reduced to other buried objects, for example, water pipes. Even if it is restricted by a gas pipe or the like.

  FIG. 5 shows another embodiment of the communication cable pipe 1 for preventing freezing failure according to the present invention.

  The freeze failure prevention communication cable tube 1 of this embodiment also includes an outer tube 2 made of vinyl chloride resin and a freeze failure prevention tube 3 inserted inside the outer tube 2. Is configured by laminating flexible tubes 5 on the inner peripheral surface and outer peripheral surface of the volume expansion absorbent material layer 4 made of polyethylene resin foam having closed cells.

  The freeze failure prevention tube 3 including the outer tube body 2, the volume absorbing material layer 4 and the flexible tube 5 laminated inside and outside of the outer tube body 2 constituting the freeze failure prevention communication cable tube 1 of this embodiment has been described above. The same reference numerals are used and the detailed description thereof is omitted, and only different points will be described.

  The freeze failure prevention tube 3 constituting the freeze failure prevention communication cable tube 1 of this embodiment is formed with a notch 3a in the circumferential direction. A cover plate 10 made of rubber having an h-shaped cross section is attached to one opening edge of the inner flexible tube 5 opened by the notch 3a formed in the freeze failure prevention tube 3. The cover plate 10 is formed to have a length that covers the space between the open ends of the flexible tube 5 by the cutout portion 3a, and the tip of the cover plate 10 is in contact with the inner peripheral surface of the other open end edge. Further, a cover 11 made of rubber having a U-shaped cross section is attached to the other edge of the opening facing the other.

  The outer flexible tube 5 in the freeze failure prevention tube 3 is larger than the cutout opening of the inner flexible tube 5 so that the outer peripheral surface of the opening edge of the volume expansion absorbent material layer 4 is partially exposed. Notched over range.

  In the case of the freeze failure prevention communication cable tube 1 formed by inserting such a freeze failure prevention tube 3 into the outer tube 2, in addition to the above-described operational effects of the freeze failure prevention communication cable tube 1, It is possible to replace only the freeze failure prevention pipe 3 without removing the communication cable.

  That is, as shown in FIG. 6, even when the communication cable C is already drawn into the rising pipe 6 when inserted into the rising pipe 6 that is the outer tube body 2, the cover plate of the freezing failure prevention pipe 3. 10 can be pushed open, and the communication cable C can be guided to the inside of the freeze failure prevention pipe 3 through the notch 3a. Then, the freeze failure prevention pipe 3 may be inserted into the rising pipe 6 while housing the communication cable C therein. On the other hand, when the freeze failure prevention pipe 3 is pulled out from the rising pipe 6, the cover cable 10 is pushed open while the freeze failure prevention pipe 3 is pulled out, and the communication cable C is pulled out through the cutout portion 3 a of the freeze failure prevention pipe 3. Good.

  At this time, the communication cable C is damaged by the opening edge of the flexible tube 5 because the opening edge of the inner flexible tube 5 facing the cover 11 and the cover plate 10 is covered. This can be prevented. Similarly, the outer flexible tube 5 is notched at an angle larger than the angle formed by the notch opening of the inner flexible tube 5 by the notch 3a so that the volume expansion absorbing material layer 4 is exposed. The communication cable C can be prevented from coming into contact with the opening edge of the outer flexible tube 5 and being damaged.

  As a result, there is no need to prepare a separate bypass circuit so that communication cables such as optical fibers are not removed or user communications are interrupted, and the freeze-fault prevention tube can be replaced smoothly. it can.

  FIG. 7 shows a modification of another embodiment of the communication cable pipe 1 for preventing freezing failure described above.

  The freeze failure prevention communication cable pipe 1 is also composed of an outer tube body 2 made of vinyl chloride resin and a freeze failure prevention pipe 3 inserted inside the outer tube body 2. Flexible tubes 5 are respectively laminated on the inner peripheral surface and the outer peripheral surface of the volume expansion absorbing material layer 4 made of a polyethylene resin foam having bubbles.

  The freeze failure prevention tube 3 comprising the outer tube 2, the volume absorbing material layer 4 and the flexible tube 5 laminated inside and outside of the outer tube body 2 constituting the freeze failure prevention communication cable tube 1 is the same as described above. Therefore, the same reference numerals are attached and detailed description thereof is omitted, and only different points will be described.

  The freeze failure prevention tube 3 constituting the freeze failure prevention communication cable tube 1 of this embodiment is laminated on the volume expansion absorbent material layer 41 having a semi-cylindrical cross section, and the inner surface and the outer surface of the volume expansion absorption material layer 41, respectively. A laminated body 3A having a semi-cylindrical cross section is formed by a flexible tube 51 having a semi-cylindrical cross section having a substantially smooth outer surface and inner surface, and the opening edges of the pair of laminated bodies 3A are opposed to each other and are substantially cylindrical. It is formed into a shape. A cover plate 10 made of rubber having a substantially h-shaped cross section is attached to one opening edge of each laminate 3A, and the tip of the cover plate 10 is the opening of the other laminate 3A facing each other. It is set so that it may contact the inner peripheral surface of an edge part.

  In the case of the communication cable tube 1 for preventing freezing failure formed by inserting such a freezing failure preventing tube 3 into the outer tube 2, in addition to the operational effects of the communication cable tube 1 for preventing freezing failure described above, communication is also possible. It is possible to replace only the freezing failure prevention tube 3 without removing the cable.

  That is, although not shown in detail, even when the communication cable is already drawn into the riser pipe 6 when inserted into the riser pipe 6 that is the outer tube body 2, the communication cable is sandwiched between the stacked bodies 3 </ b> A. In this way, the open ends are brought into contact with each other to form the freezing failure prevention pipe 3 and then inserted into the rising pipe 6 as it is. On the other hand, when the freeze failure prevention tube 3 is extracted from the riser tube 6, the freeze failure prevention tube 3 may be extracted and separated into the laminates 3A so that the open ends are separated from each other. be able to.

  At this time, even if the communication cable tries to be positioned relatively between the opposed open ends of the pair of laminated bodies 3A, the cover plate 10 covers the gap between the open ends together with the opposed open end edges of the inner flexible tube 5. As a result, the communication cable can be prevented from being damaged by the opening edge of the flexible tube 5.

  As a result, there is no need to prepare a separate bypass circuit so that communication cables such as optical fibers are not removed or user communications are interrupted, and the freeze-fault prevention tube can be replaced smoothly. it can.

  According to the present invention, it is easy to insert a communication cable, it is possible to prevent the occurrence of a freezing failure, and even if a freezing failure occurs, the freezing failure prevention tube can be easily replaced. It is possible to efficiently construct an information communication network in a cold region.

It is sectional drawing which shows one Embodiment of the communication cable pipe | tube for freeze-fault prevention of this invention. It is sectional drawing of the communication cable pipe | tube for freeze-fault prevention of FIG. It is an expanded sectional view of the A section in FIG. FIG. 2 is a half sectional view showing a specific example of a communication cable pipe for preventing freezing failure in FIG. It is sectional drawing which shows other embodiment of the communication cable pipe | tube for freeze-fault prevention of this invention. It is explanatory drawing which shows the exchange point of the freezing failure prevention pipe | tube in the communication cable pipe for freezing failure prevention of FIG. It is sectional drawing which shows the modification of the communication cable pipe | tube for freeze-fault prevention of FIG. It is explanatory drawing which shows the branch pipe which branches the conventional communication cable into a home.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Freezing failure prevention communication cable tube 2 Outer tube 3 Freezing failure prevention tube 4 Volume expansion absorption material layer 5 Flexible tube 6 Startup tube 7 Bend tube 8 Seal material 9 Rubber stopper 10 Cover plate 11 Cover

Claims (7)

  A freezing failure prevention tube comprising a volume expansion absorbing material layer inside the outer tube body and a flexible tube laminated on the inner surface and the outer surface of the volume expansion absorbing material layer, respectively, and having a substantially smooth outer surface and inner surface. A communication cable tube for preventing freezing failure characterized by being inserted.   A volume expansion absorbing material layer and a flexible tube laminated on the inner surface and the outer surface of the volume expansion absorbing material layer, respectively, and having a substantially smooth outer surface and inner surface, are arranged in the tube axis direction inside the outer tube body. A freezing failure prevention communication cable tube, wherein a freezing failure prevention tube having a cutout portion is inserted therethrough.   A volume expansion absorbent material layer having a semi-cylindrical cross section inside the outer tube, and a flexible body having a semi-cylindrical cross section that is laminated on the inner surface and the outer surface of the volume expansion absorbent material layer, respectively, and the outer surface and the inner surface are substantially smooth. A freeze failure prevention communication cable tube, wherein a freeze failure prevention tube formed in a substantially cylindrical shape by a pair of semi-cylindrical laminates having a cross section is inserted.   The flexible tube has a forked portion on one side edge, and has a fitting portion provided with a retaining portion facing the opening edge, and can slide in the fitting portion on the other side edge. A belt-shaped synthetic resin profile having a locking portion fitted and locked into the tube is spirally wound, and in the wound state, a fitting portion and a locking portion adjacent to each other are fitted into a cylindrical shape The communication cable pipe for preventing freezing failure according to claim 1, 2 or 3.   4. The communication cable tube for preventing freezing failure according to claim 1, wherein the volume expansion absorbing material is a resin foam having an expansion ratio of 20 to 50 and having closed cells.   The notch formed in the freeze-fault prevention tube is shielded by a cover plate made of rubber or the like provided so as to be openable and closable across the inner peripheral surface of the opposed open end, and the opposed open end of the inner flexible tube The edge is covered with a cover made of rubber or the like, and the outer flexible tube is cut out over a larger area than the cutout portion of the inner flexible tube so that the volume expansion absorbing material layer is exposed. The communication cable tube for preventing freezing failure according to claim 2.   A cover plate made of rubber or the like that is in contact with the inner peripheral surface of the open end of the other laminated body facing each other is provided on the inner peripheral surface of one open end of each laminate, and one of the inner flexible tubes The communication cable pipe for preventing freezing failure according to claim 3, characterized in that the opening edge of each is covered with a cover made of rubber or the like.

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