JP4207204B2 - Cable laying method and fireproof bell block - Google Patents

Description

The present invention relates to a cable laying method for laying power and communication cables such as electric wires and telephone lines in the ground using a protective duct for wiring, and a fireproof bell block used in this method. It is related to cable construction technology for power and communication.

Electric power / telephone power / communication cables are usually protected by synthetic resin wiring protective ducts (hereinafter simply referred to as “ducts”), and tunnels, ordinary roads, highways, and other sideways it is laying in the ground that is not much.
In such installation, for the efficiency of installation and maintenance and inspection of cables, one manhole and hand hole (hereinafter also referred to as “manhole”) where cables are directly exposed are usually provided at intervals of 25 m. It has been.

During this manhole construction, usually, that have the bell block is used having a through hole for a plurality of cable insertion.
The through hole for cable insertion provided in this bell block has a relatively large diameter, and the cable wired in the duct is restricted within a certain range by the diameter of the duct to be used. The internal space area is very wide.

Therefore, when a fire occurs in or near a manhole, flame, smoke, or high-temperature gas enters the duct from the opening of the bell block through-hole, and a duct with a large diameter and a large space is formed. There is a risk of expanding the fire as a passage, and the damage in the event of a fire may be immeasurable if it includes direct and indirect items.

  In particular, when a traffic accident occurs in a highway tunnel, fuel such as leaked gasoline or loaded flammable liquid accumulates in a manhole, resulting in a fire in a closed tunnel. In some cases, the damage can be even more serious.

  For this reason, various methods have been proposed to prevent the fire from expanding when a fire occurs in or near the manhole.

  For example, as a method for laying a cable, Japanese Patent Application Laid-Open No. Hei 4-21307 (Patent Document 1) has an opening at one end of a cable insertion hole formed in a bell block at an opening on a cable drawing side or a cable feeding side. A plug member in which a cable holding hole is formed is attached, and the cable holding hole of this plug member is focused and held to close most of the opening of the cable insertion hole. A method has been proposed in which the cable exposed in the formed cable insertion hole is covered with a fire spread prevention material carrying a foamable substance on the outer periphery.

In addition, in Utility Model Registration No. 2528553 (Patent Document 2) and Utility Model Registration No. 2605960 (Patent Document 3) , a cylindrical body having substantially the same diameter as the inner diameter of one end opening of the cable insertion hole is made incombustible. A cover body that is formed of a material and has a cable holding hole at the center of the base end of the cylindrical body or a lid body that does not have a cable holding hole is integrally formed on the inner periphery of the cylindrical body. Also disclosed is a method of mounting a plug member carrying a fire spread prevention material, in which a foaming material that is foamed by heat is covered with a protective film impermeable to gas and moisture, to a cable insertion hole formed in the bell block Has been.
JP-A-4-21307 (Claims and FIG. 3) Utility Model Registration No. 2528553 (Utility Model Registration Claim 1) Utility Model Registration Gazette No. 2605960 (Utility Model Registration Claim 1)

In the invention described in each of the above patent documents, the opening portion of the cable insertion hole of the bell block is closed by a lid member provided with a cable holding hole in the center, or a plug member having a lid member having no cable holding hole, Furthermore, inside the plug member, the outer and the outside of the cable, Ru der those obtained by supporting the expandable material.
Therefore, even if the inside of the manhole burns due to the occurrence of a fire, or the flame, smoke, or even high temperature gas enters the manhole, the opening is closed by the plug member, so it is formed in the bell block. The cable insertion hole and the duct fitted and held in this cable insertion hole have an excellent effect that there is almost no risk of expanding the damage as a passage of flames, smoke, and even high-temperature gas. It is.

However, poorer conditions, For example, in a car accident in the tunnel of the highway, fuel such as gasoline leaked flammable liquid which has been loaded is deposited manhole, in a case where a fire Although higher fire resistance and fire resistance are required, it is difficult to say that satisfactory results are always obtained by the conventionally proposed methods under such severe conditions.

In view of this, the inventors have studied to propose a method for laying a cable excellent in fire resistance and fire resistance that can be satisfied even under severe conditions .
As a result, the bell block, which has been conventionally formed of flame retardant synthetic resin or resin concrete, is mainly made of cement that does not contain organic substances, and is used for inserting cables formed in the bell block. The opening on the manhole side of the through hole is made of a non-combustible, flame-retardant or self-extinguishing material, and is provided with a cylindrical fire hydrant with an enlarged diameter portion at the tip, and the non-flammable on the opposite opening By installing a joint for fitting a duct made of flame-retardant or self-extinguishing resin, wiring the cable, and filling the inside of the fire hydrant with non-flammable, flame-retardant or self-extinguishing material, the above object is achieved. The present invention has been completed by finding out what can be achieved.

The cable laying method according to claim 1 of the present invention includes:
When laying power / communication cables in the ground via manholes with bell blocks on the opposite side walls using protective ducts for wiring,
The bell block ,
Is formed by a cement containing substantially no organic material as a main material, the through holes for cable insertion, which is formed in the central portion, the opening of the manhole side nonflammable, flame retardant or self-extinguishing materials A cylindrical fire hydrant having an enlarged diameter portion at the tip is provided, and the opening on the opposite side is less than half the length of the through hole, and a protrusion is formed on the outer peripheral portion. It is a bell block in which a nonflammable, flame retardant or self-extinguishing resin joint is inserted, which is composed of a cylindrical insertion portion made and a cylindrical holding portion connected to the insertion portion ,
One end portion of the protective duct the wire, fitted in a cylindrical holding portion of said joint,
After the cable that is wired on the wiring protection duct, said by way of the through hole of the bell block was introduced into the manhole through the interior cavity of the fire plugs provided in the manhole side,
Wherein the internal pore space of the wired fire plug cable and is characterized nonflammable, that to fill a material having a flame-retardant or self-extinguishing.

Moreover, the fireproof bell block according to claim 8 of the present invention,
When a power / communication cable is laid in the ground via a manhole using a wiring protection duct, a fireproof bell block provided on the opposite side wall of the manhole,
Cement that does not substantially contain organic substances is the main material ,
The opening on the manhole side of the through hole for inserting the cable formed in the center is provided with a cylindrical fire hydrant formed of a non-flammable, flame retardant or self-extinguishing material and having an enlarged diameter portion at the tip. And
The opening on the opposite side has a cylindrical insertion portion whose length is less than half of the length of the through-hole and has a protrusion formed on the outer peripheral portion, and a cylindrical shape connected to the insertion portion. A non-flammable, flame-retardant or self-extinguishing resin joint comprising a holding portion is provided.

  According to the cable laying method of the present invention using the fire-proof bell block having the above-described configuration, fuel such as gasoline leaked in a car accident in a highway tunnel and flammable liquid loaded in the manhole Even under harsh conditions such as accumulation and fire, the opening is completely sealed with a non-flammable, flame-retardant or self-extinguishing material filled inside the plug member and the bell. Since the duct fitted and held in the cable insertion hole formed in the block is protected by a non-flammable, flame retardant or self-extinguishing resin joint, the cable insertion hole or duct is protected from flame, smoke, high-temperature gas, etc. Enlarging the damage as a passage also has an excellent effect that the duct itself does not burn due to the heat of the fire.

Furthermore, since each component used in the cable laying method of the present invention has a simple structure, it is easy and easy to lay the cable, and a special period is required to provide fire resistance and fire resistance. without the conventional laying methods, in the construction period, it has such observed differences.
Particularly, in the joint for engaging and holding the duct, the length of the insertion portion to be inserted into the through hole for inserting the cable is less than half of the entire length of the through hole, so that the duct can be separated from the manhole and the dunk. Can be prevented from melting and spreading due to fire heat.
Furthermore, if a plug member composed of a plurality of divided bodies is used as the plug member, the plug member can be constructed in a shorter period of time.

  Hereinafter, a fireproof bell block of the present invention and a cable laying method using the fireproof bell block will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic explanatory view for explaining a main part of a fireproof bell block and cable laying method according to the present invention, FIG. 2 is a front view of a fire hydrant used in the present invention, and FIG. It is a figure which shows the relationship of a bell block, and the laying state of a cable.

As shown in FIG. 3, the power and communication cable 25 embedded in the ground (not shown) using the wiring protection duct 24 is exposed to the ground surface for maintenance and inspection. manhole 21 is intended to opposite walls in the laying direction of the cable 25 is formed by the bell block 22, each bell block 22, the through hole 23 of the cable inserted.

The bell block 22 in FIG. 3 is simplified, and the wall surface is formed by the single bell block 22 of the through hole 23. Usually, the shape and the size and number of the through holes are different for the wall surface formation. , Formed by a plurality of bell blocks.

In laying the cables shown in Figure 3, Ke is buried in the ground - the duct 24 to protect the table 25, from the outer wall surface of the bell block 22 (the inner wall surface of the manhole side), the through-hole 2 3 Is fitted and held in

Cable 25 pulled out from the duct 24 through the through hole 23, is drawn into the manhole 21 such as for maintenance and inspection, it kept in a state of being exposed in the space of the manhole 21.

The cable 25 kept in an exposed state in the space of the manhole 21 is further extended and fitted into the bell block 22 through the through hole 23 of another bell block 22 in the same manner as described above. It is housed in a duct inserted and held and wired (not shown).
Thus, the duct 24 to which the cable 25 is wired is buried in the ground, and the cable construction is completed.

In FIG. 3, the plug member 26 is provided for fire spreading by the through hole 23 of the bell block 22 .
The plug member 26 is formed of a nonflammable material, and has a cylindrical body 28 having an outer diameter that is substantially the same as the inner diameter of the cable insertion hole 23 , and a central portion provided at the proximal end of the cylindrical body 28. The lid body 27 has a cable holding hole 29.

This plug member 26, the by closing the opening of the cable insertion hole 23 of the bell block 22, event or burning fire occurs manhole 2 in 1 or flame and smoke manhole 2 in 1, further even in invading the hot gas, and the cable insertion hole 23 formed in the bell block 22, the duct 24 is fitted and held in the cable insertion hole 23, they flame and smoke, the further passage of the hot gas It plays a role in preventing the damage from spreading.

Figure 1 is a Ru der those described and fire resistance level block of the present invention, the main part of laying the cables.
In the present invention, the duct 4, unlike the conventional, intended to be engaged with and held by the joint 10 which is inserted and held in fireproof bell block 2, the inner surface 1a of the manhole 1 of fireproof bell block 2 The fire hydrant 6 is detachably provided.

Inside the fire plug 6, so as to enclose the cable 5 wired, non-combustible, material 11 having flame retardant or self-extinguishing properties is filled without gaps, and the fire plug 6, nonflammable, flame retardant or self-extinguishing properties The opening portion of the cable insertion hole 3 is completely sealed by the material 11 having

Fireproof bell block 2 of the present invention, the shape, number and size of the cable insertion hole 3 (pore size), etc., Ru similar der as the conventional.
Unlike conventional flame retardant synthetic resin or resin concrete, the material is mainly made of cement that does not contain organic substances, that is, concrete, in order to increase fire resistance. Is.

  Note that “substantially free of organic substances” means that synthetic resins are not included as components such as resin concrete, and a small amount of organic substances as water reducing agents and fluidizing agents are also included. It does not mean that there is no.

The joint 10 is provided on the outer surface 1b side of the manhole 1 of the fireproof bell block 2 and is inserted into the through hole 3 by reducing the diameter of the tip of the holding portion 10a that engages and holds the duct 4. The portion 10b is formed and is integrally molded with a non-flammable, flame-retardant or self-extinguishing resin .
The length of the insertion portion 10 is less than half of the total length of the through hole 3 for inserting the cable formed in the fireproof bell block 2, and the duct 4 engaged and held by the joint 10 is connected to the manhole 1 The duct 4 is prevented from being melted or destroyed by heat generated by the fire generated in the manhole 1 .

  As the non-flammable, flame-retardant or self-extinguishing resin used for the joint 10, a thermoplastic resin to which an inorganic or organic flame retardant such as antimony trioxide or chlorinated paraffin is added from the viewpoint of moldability, particularly polypropylene, etc. Polyolefin is preferred.

Further, the joint 10 and the duct 4 are preferably made of a thermoplastic resin that naturally digests within 30 seconds by a standardized combustion test according to JISC3653.
Further, when the joint 10 is molded, as shown in FIG. 1, a protrusion 13 for ensuring the fitting is provided on the surface of the fitting portion with the fireproof bell block 2.

This on the inner surface 1a of the manhole 1 Bell block 2, anti Hisen 6 Ru provided.
The inside of the fire hydrant 6 is filled with a non-flammable, flame-retardant or self-extinguishing material 11 so as to wrap the wired cable 5 so that the opening of the cable insertion hole 3 is completely formed. Even if it is sealed and the inside of the manhole 1 burns, or flame, smoke, or even high temperature gas enters the manhole 1, damage to the cable insertion hole 3 and the duct 4 communicating with the cable insertion hole 3 is increased. Can be prevented.

The fire plug 6, since its surface is exposed in the manhole 1, flames and smoke generated in the manhole 1, further since direct contact of the hot gas, incombustible, flame retardant or self-extinguishing materials it is Ru necessary der being formed.
These materials include cement, metal, ceramics, diatomaceous earth and the like, and preferred for this invention is cement, ie concrete.

  The fire hydrant 6 is formed of a cylindrical body 8 having an outer diameter substantially the same as the inner diameter of the cable insertion hole 3 and having an enlarged diameter portion 7 at one end, and is integrally formed. Alternatively, it may be composed of a plurality of divided bodies.

That is, as shown in FIG. 2, the cylindrical body 8 having the enlarged diameter portion 7 constituting the fire hydrant 6 is constituted by two divided bodies 6a and 6b obtained by cutting the central portion along the axial direction. When the fire-proof bell block 2 is fitted into the cable insertion hole 3 on the inner surface 1a side of the manhole 1 , the joining surfaces of the divided bodies 6a and 6b are combined by an appropriate means or integrated, or the cable is inserted. finally but it may also be configured to be one of the fire plug 6 by fitting the hole 3.
The number of divided bodies constituting one fire hydrant 6 and the shape thereof are not particularly limited, but 2 to 3 divided bodies are preferable from the viewpoint of production and use efficiency.

Further, the fitting portion of the cable insertion hole 3 of a cylindrical fire plug 6 is not the preferred what is reduced in diameter to facilitate insertion into the cable insertion hole 3.
Further, the enlarged diameter portion 7 is formed so that the surface thereof is flush with the surface of the fireproof bell block 2, and the surface is provided with a hole 12 for attachment to and removal from the cable insertion hole 3. It is preferable to keep it.

  In addition, as the material 11 having non-flammability, flame retardancy, or self-extinguishing properties, which is filled and filled without gaps so as to wrap the wired cable 5 inside the fire hydrant 6, inorganic fibers such as glass fiber and rock wool, Fireproof putty etc. are used.

  The fire-resistant putty is made by blending a large amount of the above-mentioned flame retardants and inorganic fillers such as aluminum hydroxide and calcium carbonate into a synthetic resin emulsion or liquid resin, and has a high viscosity. Materials such as clay-like putty MPP-45 (manufactured by Sumitomo 3M), liquid putty CP-25WB (manufactured by Sumitomo 3M) and the like are preferable for the present invention from the viewpoint of workability and fire resistance.

The above fire plugs 6 and therein nonflammable, and is filled with a material 11 having flame retardant or self-extinguishing, flame and smoke, and more measures to cut off the high temperature gas, the manhole 1 of fireproof Bell Block 2 It is desirable to apply to all of the formed cable insertion holes 3, that is, all of the cable insertion holes 3 where the current cable 5 is not wired, including the cable insertion holes 3 provided for future expansion.

A fireproof bell block according to the present invention and a cable laying method using the fireproof bell block are provided for fireproofing of power and communication cables such as electric wires and telephone wires laid underground using a protective duct for wiring. It improves the performance, especially the fire resistance around the manhole, and is widely used in various industries that use power and communication cables.

It is a schematic explanatory drawing explaining the principal part of the laying method of the fireproof bell block and cable of this invention. It is a front view of the fire hydrant used by this invention. It is a figure which shows the relationship between the manhole by a prior art, and a fireproof bell block, and the laying state of a cable.

Explanation of symbols

1 Manhole 2 Fireproof bell block 3 Cable insertion hole 4 Protective duct for wiring (duct)
DESCRIPTION OF SYMBOLS 5 Cable 6 Fire hydrant 7 Expanded diameter part 8 Cylindrical body 9 Holding hole 10 Joint 11 Material which has incombustibility, a flame retardance, or self-extinguishing property 12 Hole 13 Protrusion

Claims (9)

When laying power / communication cables in the ground via manholes with bell blocks on the opposite side walls using protective ducts for wiring,
The bell block ,
Is formed by a cement containing substantially no organic material as a main material, the through holes for cable insertion, which is formed in the central portion, the opening of the manhole side nonflammable, flame retardant or self-extinguishing materials A cylindrical fire hydrant having an enlarged diameter portion at the tip is provided, and the opening on the opposite side is less than half the length of the through hole, and a protrusion is formed on the outer peripheral portion. It is a bell block in which a nonflammable, flame retardant or self-extinguishing resin joint is inserted, which is composed of a cylindrical insertion portion made and a cylindrical holding portion connected to the insertion portion ,
One end portion of the protective duct the wire, fitted in a cylindrical holding portion of said joint,
After the cable that is wired on the wiring protection duct, said by way of the through hole of the bell block was introduced into the manhole through the interior cavity of the fire plugs provided in the manhole side,
Wherein the internal pore space of the wired fire plugs cables, noncombustible, laying the cables, characterized in that to fill a material having a flame-retardant or self-extinguishing. The bell block is
Among the through holes for inserting the cable , the cylindrical fire hydrant is also provided in the through hole through which the cable is not inserted,
The cable laying method according to claim 1, wherein the internal hole of the fire hydrant is filled with a material having noncombustibility, flame retardance, or self-extinguishing property to close the through hole. The fire hydrant is
A material having a cylindrical body having an outer diameter substantially the same as the inner diameter of the manhole- side opening of the insertion hole and having an enlarged diameter portion formed on one end face, and having a non-combustible, flame-retardant or self-extinguishing material. The cable laying method according to claim 1, wherein the cable is laid integrally with each other. The fire hydrant is
It is made of a cylindrical body having an outer diameter substantially the same as the inner diameter of the opening on the manhole side of the insertion hole, and having an enlarged diameter portion formed on one end face, and is made of a material having noncombustibility, flame retardancy, or self-extinguishing properties. The cable laying method according to claim 1, wherein the cable laying method is constituted by a plurality of formed divided bodies and integrated so as to be used at the time of use. The joint is
The cable laying method according to claim 1 or 2, wherein the cable is laid with a thermoplastic synthetic resin to which a flame retardant is added. The fire hydrant is
The cable laying method according to claim 1 or 2, wherein the main material is cement that does not substantially contain an organic substance. Non-flammable, flame retardant or self-extinguishing material that fills the inside of the fire hydrant,
The cable laying method according to claim 1 or 2, wherein the cable is a putty-like material having high viscosity and viscosity. When a power / communication cable is laid in the ground via a manhole using a wiring protection duct, a fireproof bell block provided on the opposite side wall of the manhole,
Cement that does not substantially contain organic substances is the main material ,
The opening on the manhole side of the through hole for inserting the cable formed in the center is provided with a cylindrical fire hydrant formed of a non-flammable, flame retardant or self-extinguishing material and having an enlarged diameter portion at the tip. And
The opening on the opposite side has a cylindrical insertion portion whose length is less than half of the length of the through-hole and has a protrusion formed on the outer peripheral portion, and a cylindrical shape connected to the insertion portion. A fireproof bell block characterized by being provided with a nonflammable, flame retardant or self-extinguishing resin joint comprising a holding portion . The incombustible, flame retardant or self-extinguishing resin is
The fireproof bell block according to claim 8, which is a thermoplastic synthetic resin to which a flame retardant is added.

Images