JP4160151B2 - Expansion joint for underground burial - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion joint for underground burial, and more particularly to an expansion joint for underground burial that prevents damage to a rubber flexible tube and prevents an unexpected accident.
[0002]
[Prior art]
Expansion joints (flexible joints) have the performance of expansion joints, and are also called flexible expansion pipes (simply flexible pipes), where pipes are buried in the soil from structures such as pump stations and aqueduct attachments, Used in soft ground where uneven settlement occurs. It is used to absorb the amount of abrupt settlement at these locations that cannot be absorbed by conventional expansion joints, and it is used to dampen the connection parts of devices that generate specific vibrations such as pumps and blowers. The flexible pipe is usually formed in a bellows shape, and can be expanded and contracted and bent at a large angle in a shape that is not unreasonable in structure. Currently, there are two types of water pipes, stainless steel and rubber. Things are mainly used. Further, in the classification according to the type of bending, there are many types of classifications such as a universal type that freely bends up and down and left and right and a hinge type that bends up and down. Depending on the purpose of use and geological conditions, subsidence absorption may take up to about 1 m. In order to absorb such a large amount of settlement, there are a method of directly joining two flexible tubes, a method of using two flexible tubes with a short tube interposed therebetween, and the like.
[0003]
By the way, the conventional expansion joint is wound with a reinforcing cloth around a flexible tube made of rubber, receives internal pressure, supports external pressure with a reinforcing ring, and covers with a rubber layer for contact with the outside. The ends are configured to be connected to expansion joints or adjacent structures or pipes by attaching caps such as nipple flanges, tie bolts or hinge fittings.
[0004]
[Problems to be solved by the invention]
However, the conventional expansion joint described above has the following problems. That is,
(1) Since the outer surface of the main part of the flexible tube is made of rubber, it hits square stones and structures directly during transportation and when the flexible tube is backfilled, leading to laceration. .
(2) After laying the flexible tube, when excavating the vicinity of the flexible tube for other piping work such as electricity and gas, it was sometimes damaged by a shovel or pickaxe.
{Circle around (3)} Since the soil is in close contact with the periphery of the flexible tube in the soil, the deformation of the flexible tube is restricted by the earth and sand, and an unreasonable stress is generated.
[0005]
In view of the above problems, the present inventor has conducted various researches and tests. As a result, the rubber surface portion of the expansion joint is covered with a strong cover, and a flexible vibration absorbing material is interposed between the rubber surface and the cover. It was clarified that it can protect the rubber of the elastic body, reduce the deformation limit in the soil, can be displaced more freely, and can increase the durability.
[0006]
The present invention was devised based on the above viewpoints. The purpose of the present invention is to increase the strength of the outer surface layer and absorb the displacement in the intermediate gap to increase the durability. It is to provide an expansion joint that can be used.
[0007]
[Means for Solving the Problems]
And the expansion joint of Claim 1 of this invention as a means for solving the said subject is a basement which consists of a flexible inner pipe part and the nozzle | cap | die attached integrally to the both ends of this inner pipe part. An expansion joint for embedment, provided with an outer surface protection cover with a space around the outer periphery of the inner tube portion, a sponge layer provided in the space, and the sponge layer contacting the outer surface protection cover surface of the inner tube portion It is characterized by absorbing the displacement while preventing it.
[0008]
In the expansion joint according to claim 2 of the present invention, the inner tube portion is composed of an inner rubber layer, a reinforcing cloth layer, a reinforcing wire, an intermediate rubber layer, an outer peripheral reinforcing cloth layer, and an outer peripheral rubber layer, It consists of a cylinder formed from a rigid metal, glass fiber reinforced plastic, carbon fiber reinforced plastic, ceramic fiber reinforced plastic, or the like. An expansion joint according to a third aspect is the expansion joint according to the first or second aspect, wherein the sponge layer has a hardness Hs of 5 to 80 (SRIS-C) and a porosity of 45 to 95%. Here, the sponge layer can be usually formed of sponge rubber (a vulcanized rubber having a sponge-like porous structure). However, the sponge forming the sponge layer is not limited to the sponge rubber, and includes a porous non-woven fabric (cotton-like).
[0009]
In the present invention, the SRIS-C hardness (hardness) is a method of observing the scale after 30 seconds by applying a load of 1 kg using an SKER-0101 4.2 (ASKER C type tester manufactured by Kobunshi Keiki Co., Ltd.) ) Test method. Examples of the metal used for the outer protective cover include steel and stainless steel. The plastic reinforced with fibers and the like is not particularly limited, but conventionally known resins such as epoxy resins, polyester resins, polyamides, and polyethylenes can be used. Further, as a reinforcing material, not only glass, carbon and ceramic but also aramid can be used. As the form of the fiber, roving, yarn, chopped strand, mat, woven or the like can be used.
[0010]
If the hardness Hs of the sponge layer is less than 5, there is a possibility that the compression set becomes too soft and the permanent set becomes unusable. If Hs exceeds 80, the displacement of the inner rubber layer 2 is limited, Vibration cannot be absorbed and durability is deteriorated.
[0011]
According to the expansion joint of the present invention, it is interposed between pipes or between pipes and structures, and is displaced as the structures at both ends are displaced, so that the flexible inner pipe part is deformed to absorb the displacement. Even if it is buried in the soil and external pressure is applied from the surroundings, the outer surface protection cover takes charge, and external pressure is not applied to the flexible inner tube portion. Even if there are square stones or the like around, there is no contact with the flexible inner tube portion, so it is not damaged. In addition, since a sponge layer is provided between the inner tube portion and the outer surface protection cover, the inner tube portion and the outer surface protection cover do not come into direct contact with each other. There is nothing.
[0012]
【The invention's effect】
As is clear from the above description, according to the expansion joint of claim 1, an outer surface protective cover is provided with a space around the outer periphery of the inner tube portion, a sponge layer is provided in the space, and the inner tube is formed by the sponge layer. Prevents contact with the outer surface of the protective cover and absorbs the displacement, so it can absorb the displacement well with a simple structure, and the flexible part is not exposed to the outside, so it touches an external object and is damaged. Since there is no, durability can be improved.
[0013]
According to the expansion joint of claim 2, the inner tube portion is constituted by an inner rubber layer, a reinforcing cloth layer, a reinforcing wire, an intermediate rubber layer, an outer peripheral reinforcing cloth layer, and an outer peripheral rubber layer, and the outer protective cover is rigid. Because it is made of a cylindrical body made of metal, glass fiber reinforced plastic, carbon fiber reinforced plastic, ceramic fiber reinforced plastic, etc., the inner tube can withstand internal pressure, and an external protective cover is provided for external pressure. Since it takes charge, it is possible to arbitrarily increase the pressure resistance against the external pressure. According to the expansion joint of claim 3, since the sponge layer has a hardness Hs of 5 to 80 (SRIS-C) and a porosity of 45 to 95%, the inner tube portion can be freely displaced, Durability is improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the drawings. 1 to 2 show an embodiment of the present invention, FIG. 1 is a front view of an expansion joint, and FIG. 2 is a piping diagram showing an example in which the expansion joint is provided in the piping.
[0015]
In general, the expansion joint 1 of the present embodiment includes a flexible inner tube portion 2 and caps 3 and 4 integrally attached to both ends of the inner tube portion 2 so as to cover the inner tube portion 2 and to protect the outer surface. 5 is provided, and a sponge layer 6 is filled between the inner tube portion 2 and the outer surface protective cover 5.
[0016]
In the inner tube portion 2, a reinforcing cloth layer 12, an intermediate rubber layer 13, a reinforcing cloth outer layer 14, and an outer rubber layer 15 are sequentially arranged on the outer side from the innermost inner rubber layer 11, and the reinforcing wire 16 is connected to the intermediate rubber layer 13. It is embedded and formed. The bases 3 and 4 are integrally attached to both ends of the inner pipe portion 2.
[0017]
The inner rubber layer 11 of the inner tube 2 is made of natural rubber or synthetic rubber such as chloroprene rubber (CR), styrene butadiene rubber, butadiene rubber, butyl rubber (IIR), ethylene propylene rubber (EPM, EPDM), and the like. Therefore, natural rubber or a rubber obtained by mixing natural rubber and synthetic rubber is suitable. The inner rubber layer 11 includes a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, a reinforcing agent such as carbon black, a filler, a softening agent, an anti-aging agent, etc., and vulcanization / molding. Can be obtained. It is preferable to use a rubber tube satisfying the specifications of the rubber tube suitable for the application and having a rubber hardness at the time of vulcanization of Hs (JIS A) of 50 to 65.
[0018]
The reinforcing cloth layer 12 and the reinforcing cloth outer layer 14 are layers that protect the rubber layers 11 and 15 from the reinforcing wire 16 as well as the internal pressure of the flexible portion of the expansion joint 1. The tire cord used for automobile tires, etc. is processed with adhesive resin and rubbed with rubber paste (gum dip) and the rubber sheet is stretched to change the angle, and multiple sheets (4 to 6 sheets) according to the internal pressure ) Paste to form. The reinforcing cloth layer 12 protects the inner rubber layer 11 from the reinforcing wire 16, and the reinforcing cloth outer layer 14 protects the outer rubber layer 15 from the reinforcing wire 16.
[0019]
The intermediate rubber layer 13 is a layer formed by embedding the reinforcing wire 16, and preferably has good adhesion to the reinforcing wire 16, the reinforcing cloth layer 12, and the reinforcing cloth outer layer 14 and is excellent in breaking. As the rubber composition of the intermediate rubber layer 13, the above-mentioned various rubbers can be used. In order to prevent breakage during bending, the rubber hardness at the time of vulcanization is softer than the inner rubber layer, Hs (JIS A ) Is preferably 40 to 50. The intermediate rubber layer 13 is made of a rubber raw material, such as a vulcanizing agent, a vulcanization accelerator, a vulcanizing aid, a reinforcing agent such as carbon black, a filler, a softening agent, and anti-aging, as in the formation of the inner rubber layer 11 It is formed by compounding, etc., vulcanizing and molding.
[0020]
The outer rubber layer 15 is partly exposed in the soil and is the same natural rubber as the inner rubber layer 11, or chloroprene rubber (CR), styrene butadiene rubber, butadiene rubber, butyl rubber (IIR), ethylene propylene rubber (EPM). , EPDM) and the like can be used. Since the outer rubber layer 15 may be exposed to the outside, CR, EPM, EPDM, etc. having durability against aging are suitable. The outer rubber layer 15 is formed in the same manner as the inner rubber layer 11. As for the standard, it is preferable to use a rubber tube that satisfies the standard of a rubber tube suitable for the application, and has a rubber hardness at vulcanization of Hs (JIS A) of 50 to 65.
[0021]
The reinforcing wire 16 is a member responsible for the load applied to the reinforcing cloth layers 12 and 14, and the load applied to all the reinforcing wires 16 is W = P × D × H (where P: internal pressure (kg / cm ² )), D: inner diameter (cm), H: pressure receiving width (cm)), and if this load W is applied to the wire, the wire has an allowable stress of 800 to 1000 kg / cm ² to withstand the cutting load at two locations on the circumference. Determine the thickness and number of turns. As the wire, a galvanized iron wire having a diameter of 5 mm is usually used.
[0022]
The caps 3, 4 are formed by flanges and are integrally formed at both ends of the inner tube portion 2. The bases 3 and 4 are used to connect the expansion joint 1 to the structure, piping, or expansion joints. Rubber packings 3 a and 4 a having the same composition as the inner rubber layer 11 are formed on the outer surfaces of the caps 3 and 4, respectively. When the rubber packings 3a and 4a are connected to the adjacent members, it is not necessary to interpose the packing separately, so that the connecting operation becomes easy and the cost of the packing can be reduced.
[0023]
The outer surface protection cover 5 prevents the inner pipe portion 2 from being crushed when subjected to earth pressure, a load when passing through the vehicle, etc., and directly hits an angular stone or structure, or is used for flexible piping for other piping work. It is a member that covers and prevents damage by shovel, pickaxe, etc. when digging up the vicinity. As the material of the outer surface protective cover 5, a reinforced plastic such as a metal such as steel or stainless steel, a glass fiber reinforced plastic, a carbon fiber reinforced plastic, or a ceramic fiber reinforced plastic is used. The cross-sectional area of the outer protective cover 5 varies depending on the external pressure and the diameter. The gap between the inner tube portion 2 and the outer surface protective cover 5 can be set within a large range by design displacement. The gap between the inner pipe part 2 and the outer surface protection cover 5 acts as a free space that can be displaced without being affected by the buried soil as a displacement absorbing space of the expansion joint 1, and is displaced without being subjected to excessive stress. And durability can be improved. Furthermore, the surface of the flexible inner tube 2 is protected by providing a sponge layer 6 in the gap between the inner tube portion 2 and the outer surface protective cover 5.
[0024]
The sponge layer 6 is a member that absorbs displacement, and is formed from foamed rubber or foamed plastic such as foamed polyurethane, foamed polystyrene, and foamed polyethylene so as to be flexible and elastic. The hardness Hs of the sponge layer 6 is 5 to 80, more preferably 15 to 70 in terms of SRIS-C hardness. If the hardness Hs is less than 5, there is a possibility that the compression set becomes too soft and the permanent set becomes unusable. If the hardness Hs exceeds 80, the displacement of the inner rubber layer 2 is limited, and the durability is limited. Becomes worse. The specific gravity of the sponge layer 6 is not particularly limited, but is generally about 0.5 to 0.055 g / cm ³ and the porosity is about 40 to 95%.
[0025]
The rubber material of the foam rubber is not particularly limited, and those conventionally used as rubber elastic bodies are used. The types include ethylene-propylene-diene rubber (EPDM), polynobornene rubber, styrene-butadiene rubber (SBR), chloroprene rubber (CR), silicone rubber, epichlorohydrin rubber, chlorinated ethylene-propylene-diene rubber (CI-EPDM). ), Natural rubber, isoprene rubber, butyl rubber and the like are preferably used. Of these, EPDM, CI-EPDM, and epichlorohydrin rubber are particularly preferably used.
[0026]
In addition, as a material for the foamed polyurethane, conventionally known urethane foam base materials such as polyhydroxyl compounds and polyisocyanate compounds are used. Conventionally known materials can be used for the base material of the foamed plastic such as foamed polystyrene and foamed polyethylene.
[0027]
For forming the expansion joint of the present invention, first, the bases 3 and 4 are installed in the mold, and the rubber raw material, the vulcanizing agent, the vulcanization accelerator, the vulcanizing aid, carbon black and the like forming the inner rubber layer 11 are formed. A mixture of reinforcing agent, filler, softener, anti-aging agent, etc. is injected and molded. Next, a reinforcing cloth layer 12 is formed by laminating the molded body by applying an adhesive resin processing (gum dip) to the tire cord and rubbing rubber paste and attaching a rubber sheet to the tire cord at different angles. Next, after winding the reinforcing wire 16 around the molded body formed up to the reinforcing fabric layer 12, the rubber raw material, the vulcanizing agent, the vulcanization accelerator, and the vulcanizing auxiliary agent that are installed in the mold and form the intermediate rubber layer 13 are obtained. Then, a mixture of a reinforcing agent such as carbon black, a filler, a softening agent, an anti-aging agent and the like is injected and molded. Next, the molded article formed with the intermediate rubber layer 13 is processed with an adhesive resin processing (gum dip) on the tire cord and rubbed with rubber paste and laminated with a rubber sheet to form a reinforcing cloth layer 14 by superimposing them at different angles. To do. Subsequently, the outer rubber layer 15 is formed by being installed in a mold, and after the die 3, 4 and the inner tube portion 2 form an integrated body, vulcanization molding is performed.
[0028]
Finally, the outer surface protective cover 5 and the vulcanized molded body of the inner tube portion 2 are arranged in a mold, and a foamed rubber material is injected into the gap between them and foamed to produce an expansion joint.
[0029]
The expansion joint configured as described above can be used in the same manner as a conventional flexible tube. That is, when the displacement is large, two expansion joints are provided. As shown in Fig. 2, if the expansion joint is separated by L at a horizontal distance and the short pipe is installed horizontally, as shown in Fig. 2, if the Y sinks and tilts by θ ° from the horizontal, the expansion amount ΔL of the expansion joint is It is calculated as follows.
ΔL = XL
Where X is the distance between the expansion joints after displacement = Y / sin θ,
L = Y / tan θ, Y is the amount of displacement in the vertical direction.
Since the elongation amount ΔL is absorbed by two expansion joints, one is ΔL / 2.
[0030]
In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation implementation is possible. Incidentally, in the embodiment described above, vulcanization molding and foaming are performed after forming an expansion joint shape, but a sponge layer may be formed after sequentially performing vulcanization molding. Moreover, although shown in the example which comprised the nozzle | cap | die with the flange, you may form one side as a flange and the other as a bevel end or both at a bevel end.
[Brief description of the drawings]
FIG. 1 is a front view of an expansion joint according to an embodiment of the present invention.
FIG. 2 is a piping diagram showing an example of arrangement of expansion joints.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Expansion joint, 2 ... Inner pipe part, 3 ... Base, 4 ... Base, 5 ... Outer surface protection cover, 6 ... Sponge layer, 7 ... Embedded piping, 11 ... Inner rubber layer, 12 ... Reinforcing cloth layer, 13 ... Intermediate rubber layer, 14 ... Outer reinforcing cloth layer, 15 ... Outer rubber layer, 16 ... Reinforcing wire

Claims (3)

An expansion joint for underground embedding comprising a flexible inner tube portion and a base integrally attached to both ends of the inner tube portion, and an outer surface protective cover with a space around the outer periphery of the inner tube portion An expansion joint for underground embedment, wherein a sponge layer is provided in the gap, and the sponge layer prevents contact with the outer protective cover surface of the inner tube portion and absorbs displacement. The inner tube portion is composed of an inner rubber layer, a reinforcing cloth layer, a reinforcing wire, an intermediate rubber layer, an outer peripheral reinforcing cloth layer, and an outer peripheral rubber layer, and the outer protective cover is a rigid metal tube, glass fiber reinforced plastic, The expansion joint for underground embedment according to claim 1, comprising a cylindrical body formed of carbon fiber reinforced plastic or ceramic fiber reinforced plastic. The expansion joint for underground embedment according to claim 1 or 2, wherein the sponge layer has a hardness Hs of 5 to 80 (SRIS-C) and a porosity of 45 to 95%.

Images