JP2012127391A - Molding joint for piping, method for manufacturing the same and method for constructing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding joint for piping which can be manufactured at a low cost with a simple structure and a small number of components, ensures sufficient sealing property in a joined portion, and facilitates attaching and removal, thereby enabling easy replacement and reconstruction of a pipe, and to provide a method of manufacturing the same.SOLUTION: This molding joint for piping is molded by compression molding or injection molding, is a single molded product constituted of a single rubber-like elastic body as a whole and is used in a fixed shape. By using the molding joint for piping, piping construction is performed by connecting a socket of the molding joint to an end portion of a pipe and fastening the socket by a metal band.

Description

  The present invention relates to a molded joint for piping used for a connecting portion of a pipe through which liquid or gas circulates, a manufacturing method thereof, and a construction method for joining a pipe and a joint.

  Connection of piping for circulating water, gas, etc., such as a drain pipe, a water pipe or a vent pipe, is generally performed via a joint between the straight pipe and the straight pipe. Also, when changing the direction of piping, joining, branching, etc., it is possible to prevent the pipe from being crushed and the flow path in the pipe from being narrowed during construction work, facilitating molding and simplifying construction work. From the viewpoint of cost reduction and the like, a joint formed in a bent shape or a branched shape and a straight pipe are joined and connected.

The method for joining the joint and the pipe as described above differs depending on the material of the pipe, pressure resistance, and the like. For example, in the case of a metal pipe, welding or screw joining is generally used, and a seal tape or an adhesive is used for the screwed portion in order to improve hermeticity.
Further, in the case of a pipe made of hard vinyl chloride resin, the joint surface is swollen and integrated using a dedicated adhesive, and joined. In addition, there are various methods such as electrothermal fusion in polyethylene piping and brazing or crimping in copper piping.

  However, in any of the above joining methods, in the case of repair or repair, incorrect connection, breakage, etc., when pipe replacement or construction rework is performed, the pipe where the adhesive is used is cut. New fittings must be provided.

  Moreover, when joining resin piping only with an adhesive agent, there exists a possibility that sufficient airtightness may not be acquired by the application | coating of an adhesive agent insufficient, hardening drying in the middle, entrapment of a bubble, etc. Further, problems such as contamination of the fluid in the piping and the surroundings of the piping due to the excessive adhesive protruding into and out of the piping, the release of volatile organic compounds (VOC) in the solvent of the adhesive, and solvent cracks have occurred.

  In addition, in the above-described joining method, if the joint between the pipe and the joint is loose and a gap is formed, or conversely, if the insertion is too tight and the insertion is shallow, there is a possibility that the pipe may come off or the sealing performance may be insufficient. is there. For this reason, it is necessary to strictly control the dimensional accuracy at the joint between the pipe and the joint, or to cut the pipe in a vertical cross section and perform processing such as correction of crushing and chamfering.

To solve the above-mentioned problems, a mechanical joint method is used in which various parts such as rubber packing rings placed at the joints are mechanically tightened and adhered to each other in various resin pipes and aluminum three-layer pipes. (For example, see Patent Documents 1 to 3).
Such a mechanical joint method can connect pipes of different materials, is easy to construct, and can be repeated over and over without cutting the pipe when reworking. It has the advantage of being able to.

Further, as a simpler method, when it is desired to introduce a bent portion into the pipe, the flow path may be bent by connecting a hose to a part of the pipe instead of the joint.
In piping using such a hose, the hose itself serves as a packing ring, so there is often no need for a rubber packing ring, and the joint can be fixed simply by band fastening or clamping. Depending on the degree of sealing required, it may only be inserted. Therefore, it can be repeatedly attached and detached, and only a part of the pipe can be easily replaced. Furthermore, since the hose has flexibility, it has an advantage that it is not easily damaged by fatigue against thermal expansion and contraction.

JP-A-6-01797 JP-A-11-210955 JP 2000-55256 A

  However, since the mechanical joint as described above has a large number of components, the cost is high and the work may be complicated. In addition, since the construction piping by the mechanical joint has a rigid structure, fatigue is caused by repeated vibration, thermal expansion, and contraction, and the joint, a part of the pipe, a support fitting, or the like may be damaged.

  On the other hand, in the case of piping using a hose, the hose bends due to its own weight.Therefore, in cases such as when it is necessary to construct with a certain gradient to promote the water flow in the piping in a non-pressure channel, the hose is frequently used. It is difficult to install fixed piping. In addition, the hose cannot substitute for the role of the joint other than the bending, and the joint is necessary in the case of branching in the hose pipe.

The present invention has been made to solve the above technical problem, and can be manufactured at a low cost with a simple structure with a small number of parts, and sufficient sealing performance can be obtained at the joint. And since it is easy to attach and detach, it aims at providing the molded joint for piping which can perform replacement | exchange of piping, and redoing of construction simply, and its manufacturing method.
Another object of the present invention is to provide a suitable construction method using the molded joint for piping.

The molded joint for piping according to the present invention is a single molded product made entirely of a single rubber-like elastic body, and is used in a fixed shape.
According to such a joint, since it can be easily repeatedly attached and detached, a part of the piping can be exchanged or the construction can be performed again easily.

In the pipe joint, the rubber-like elastic body is preferably ethylene propylene diene rubber having a heat resistant temperature of 110 ° C. or higher and a durometer hardness of 60 to 80.
Such ethylene propylene diene rubber is a suitable rubber-like elastic body from the balance of strength, heat resistance, physicochemical properties and material cost.

Moreover, it is preferable that the molded joint for piping has a wall thickness of 3.0 to 10.0 mm.
If it is a receptacle with a thickness within the above range, the adhesiveness to the tube can be maintained without expanding the diameter even with a water pressure of about 0.05 MPa.

Furthermore, it is preferable that two ring-shaped ribs are provided on the outer periphery of the receptacle.
Such a rib makes it possible to clarify the mounting position of the metal band or the like and prevent the pipe from coming off when the outer periphery of the receiving port is wound around a metal band or the like and the joint is fixed to the pipe.

Moreover, the manufacturing method of the molded joint for piping which concerns on this invention is shape | molded by compression molding or injection molding.
According to such a molding method, the pipe joint can be easily obtained by a single process.

Furthermore, the construction method of the molded joint for piping according to the present invention is characterized in that the receiving port of the joint for piping is connected to the end of the pipe and is tightened with a metal band.
According to such a method, it is possible to simply perform piping construction excellent in hermeticity without using an adhesive, and it is also easy to replace a part of the piping and redo the construction.

According to the molded joint for piping according to the present invention, it can be easily and repeatedly attached and detached, and even a non-skilled person can easily perform the piping work, and can easily replace a part of the pipe or redo the construction. Can also be achieved. Moreover, since the said joint has few parts and is a simple structure, it is easy to process compared with a mechanical joint, and can reduce the cost of manufacture and piping construction.
Moreover, according to the construction method according to the present invention using the joint, since a sufficient sealing property can be obtained at the joint without using an adhesive, and attachment and removal are easy. Redoing can be easily performed.

It is sectional drawing of the elbow joint of the molded joint for piping which concerns on this invention. It is sectional drawing of the cheese joint of the molded joint for piping which concerns on this invention. It is the figure which showed the failure example of the band fastening of the receptacle outer periphery of an elbow joint. (A) is the perspective view which showed the outline of the piping construction example of the shelf and watering pipe for gardening, (b) is an enlarged view of the watering part of (a). It is the figure which showed the outline of the piping construction example for blindfolding of an electric cable. It is the figure which showed the outline of the piping construction example of the underground protective pipe of an electric cable.

Hereinafter, the present invention will be described in detail with reference to the drawings.
The molded joint for piping according to the present invention is a single molded product made entirely of a single rubber-like elastic body, and is characterized by being used in a fixed shape.
By adopting the configuration as described above, the molding process becomes easy, and the pipes to be joined can be joined as they are without being chamfered at the ends, etc. while being cut with a roller-type cutting machine or the like. Can do. Therefore, compared with the method etc. which tighten using several components, such as a mechanical coupling and a rubber packing ring, the cost of piping construction can be reduced.

As described above, the joint according to the present invention comprises the entire joint as a simple structure made of a single material and having a small number of parts.
In molding that divides into multiple parts with different materials and two-color molding, in order to prevent cracks and peeling at the boundary between different materials and parts, the mutual materials are limited, the shape is complicated, and pre-processing and post-processing This is not preferable because it increases the processing cost.

  Examples of the rubber-like elastic body that is the material of the joint include rubber and elastomer. For example, butadiene rubber, chloroprene rubber, acrylonitrile butadiene rubber, isoprene rubber, styrene butadiene rubber, natural rubber, urethane rubber, sulfide rubber, phosphazene, One kind of ethylene propylene rubber, ethylene propylene diene rubber, epichlorohydrin rubber, fluorine rubber, silicon rubber, or a uniform mixture of two or more of these can be used. When heat resistance is not required, thermoplastic elastomers such as polyolefin and polystyrene can also be used.

In addition, the phrase “used in a fixed shape” means that the joint is not used by being bent and deformed like a flexible hose, but is used in a state in which the shape when molded is maintained. means.
As a result, the pipe diameter can be reliably maintained even when the pipe structure is turned in a narrow range such as right angle bend, right angle merge, right angle branch, etc., and the strength and rigidity of the joint itself can be improved. In addition, it is possible to maintain the gradient necessary for the water flow in the non-pressure channel.
On the other hand, taking advantage of the properties of the elastic body, due to the deformability that can follow the thermal expansion and contraction of the tube and the displacement in the insertion direction up to about 45 °, the sealing property with the tube without using an adhesive or packing ring Can be maintained.

  Specific examples of the joint according to the present invention mainly include a right angle elbow joint and a right angle cheese joint. In addition to this, taking advantage of the above-described features, socket joints, 45 ° elbow joints, 45 ° cheese joints, large elbow joints, large curved cheese joints, variable diameter cheese joints, Y-shaped joints, variable diameter joints, variable diameter The present invention can also be applied to various types of joints such as an eccentric joint, an eccentric socket joint, a merging mass, a hopper, a trap, and a bushing.

The rubber-like elastic body constituting the pipe joint is preferably ethylene propylene diene rubber having a heat resistant temperature of 110 ° C. or higher and a durometer hardness of 60-80.
Ethylene propylene diene rubber is a material having high strength and excellent heat resistance, weather resistance, etc., and having a heat resistant temperature of 110 ° C. or higher can provide a joint that can withstand repeated hot water flow. it can.
In addition, the ethylene propylene diene rubber has a durometer hardness within a range of 60 to 80 as a hardness suitable for absorbing vibration and thermal expansion and contraction without fatigue failure even when vibration and thermal expansion and contraction are repeated in the joint. It is preferable that
Molded joints made of such materials have sufficient strength and heat resistance, and absorb vibration and thermal expansion and contraction without the use of expansion joints and exchange joints that have a complicated structure and are made up of multiple parts. Moreover, it can be obtained at a lower cost than a metal joint.
The durometer hardness is generally used to relatively represent the hardness of rubber. In the present invention, the durometer hardness is represented by a measured value based on JIS K 6253 and JIS K 6250.

Moreover, it is preferable that the joint has a wall thickness of 3.0 to 10.0 mm.
If the wall thickness is less than 3.0 mm, it may be too thin and bend, for example, with a water pressure of about 0.05 MPa, which is the minimum required water pressure in the pressureless water distribution pipe, and may expand and leak.
On the other hand, if the wall thickness exceeds 10.0 mm, the outer diameter of the receiving port becomes larger than the difference between the maximum diameter and the minimum diameter of the applicable diameter range of a normal metal band used for tightening the outer periphery of the receiving port. It becomes difficult.

The joint is preferably molded by compression molding or injection molding.
Generally, it is preferable to mold by compression molding when the material is rubber or elastomer, and by injection molding when the material is thermoplastic elastomer, so that it can be easily molded as a single part by a single process. And cost reduction can be achieved.

Moreover, in piping construction of the joint, it is preferable that the receiving port is connected to the end of the pipe and is tightened with a metal band.
Since the joint is made of a rubber-like elastic body, the tightness at the joint with the tube can be ensured by tightening with a metal band without using an adhesive. In addition, since there is no need to use an adhesive, there is no problem of dirt, VOC, solvent cracks, etc. due to the adhesive inside and outside the pipe, and pipe construction with sufficient sealing performance even for pipes with wide dimensional tolerances. And the re-doing can be easily performed.

The pipe is generally a fluid transport pipe for transporting various gases and liquids, and fluids that are a mixture of them with a solid, but is not necessarily limited to this, and is fixed as described later. Piping for the purpose of blindfolding or protecting objects may be used.
Moreover, although the shape of the pipe | tube used for normal piping is a straight pipe | tube with a circular cross section, it is not limited to this. The curved pipe or the cross section may be a polygonal shape, an elliptical shape, or the like. In this case, a joint that is molded according to the tubular shape may be used.

As the metal band, a commercially available wire band, plate band, hose clamp, binding band or the like is inexpensive and can be suitably used.
By tightening the elastic receiving port with a rigid metal band, the rigidity of the receiving port is supplemented, effectively preventing the pipe from being pulled out or leakage of fluid in the pipe due to external expansion or external force. , Sealability can be ensured.
Further, even if the finished dimension of the diameter of the receiving port is too large with respect to the outer diameter of the tube, the pressure resistance is not affected because the metal band is used for tightening. For this reason, the range of a dimensional tolerance can be taken wide, and a yield improvement and cost reduction can be aimed at.

At the time of piping construction using the metal band as described above, it is preferable that two ring-shaped ribs are provided on the outer periphery of the receiving port of the molded joint.
1 and 2 are sectional views of an elbow joint 1 and a cheese joint 2 provided with ribs 3, respectively.
FIG. 3 shows an example of a case where the band tightening of the joint portion fails in the elbow joint 11 in which the rib is not provided in the receiving port. As shown in FIG. 3, after inserting the end of the straight pipe 14 into the receiving port of the elbow joint 11, the metal band 15 is accidentally hung at a deeper position away from the receiving port than the original mounting position and tightened as it is. There is a possibility that the end of the tube 14 is pushed back, resulting in poor tightening.
For this reason, as shown in FIG. 1 and FIG. 2, if two ring-shaped ribs 3 are provided on the outer periphery of the receiving opening of the molded joint, corresponding to the width of the band, the attachment when winding the metal band is performed. The position can be determined reliably, and the displacement of the metal band and the disconnection of the tube can be prevented.

The shape of the rib is not limited to the case where the cross-sectional shape is a trapezoid as shown in FIG. 1, but may be a curved shape such as a semicircle, or a polygonal shape such as a quadrangle or a triangle.
However, the protruding height and width of the ribs are such that the metal band can be easily hung and that the mounting position of the metal band does not deviate and need to be high enough to be fixed. . When the height and width of the rib are large, an appropriate rubber elasticity of the receiving port is impaired, a material cost increases with an increase in the volume of the joint, and molding processability is lowered, which is not preferable.

The joint according to the present invention as described above can be applied to various pipes for water and gas such as a drain pipe, a water pipe or a vent pipe.
It can also be applied to piping for other purposes. Specific examples thereof are shown in FIGS.
Since the joint can be easily attached and re-executed, for example, a shelf-like structure such as a gardening shelf and watering pipe as shown in FIG. 4 can be assembled. As shown in FIG. 4A, the straight pipe 24 is joined and assembled using an elbow joint 21 and a cheese joint 22. At this time, as shown in FIG.4 (b), it comprises so that a hole may be appropriately drilled in the straight pipe | tube directly above a plant, and watering may be made from this hole.

Further, the present invention is not limited to the case where the inside of the pipe is a fluid. For example, it is used for blindfolding of an electric cable in an office or home as shown in FIG. 5, and protection when the electric cable is buried in the ground as shown in FIG. It can also be suitably used for pipe construction as a pipe. In these, electric cables are passed through straight pipes 31 and 41 connected by elbow joints 31 and 41, cheese joint 32, and socket 46.
Furthermore, since the joint can also be applied to piping of polyolefin pipes and polyester pipes that do not contain lead or plasticizer, it is suitable for daily use such as water play or toys that roll glass balls in the pipe. Is also suitable.

  If it is a simple piping system or a temporary piping system that does not require a high degree of sealing at the joint, such as the above-mentioned watering pipe or blindfold pipe, tightening with a metal band around the receiving port is omitted. There is no problem.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not restrict | limited by the following Example.
[Test 1]
By compressing and molding ethylene propylene diene rubber (EPDM), an elbow joint provided with a rib as shown in FIG. 1 and a cheese joint (26 mm diameter) provided with a rib as shown in FIG. It was produced as one molded product.
At this time, joints having durometer hardness (JIS K 6253, JIS K 6250 compliant) values as shown in Table 1 and joint thicknesses as shown in Table 1 are produced. did.
Insert a rigid polyvinyl chloride resin straight pipe (outer diameter: 26 mm) into each joint and join it, tighten the outer periphery of the receptacle with a metal band (stainless steel wire band), and evaluate the joint stretchability and pressure resistance at this joint. went.
The evaluation of stretchability was performed by measuring the maximum amount of deformation when the pipe was pulled out from the joint. The pressure resistance was evaluated by increasing the water pressure in the pipe filled with tap water and measuring the maximum water pressure at which no water leakage occurred.
These evaluation results are shown in Table 1. The evaluation of stretchability was as follows: ○: 14 mm or more, Δ: 8.4 mm or more, x: less than 8.4 mm, or measurement impossible. Moreover, evaluation of pressure resistance was made into (circle): 0.1MPa or more, (triangle | delta): 0.05-0.1MPa, x: less than 0.05MPa.

From the results shown in Table 1, a molded joint made of EPDM having a durometer hardness of 60 to 80 and a wall thickness of the receiving port of 3.0 mm or more has good stretchability and is attached to the pipe and re-executed. It was confirmed that the pressure resistance was excellent and the pressure resistance was excellent.
Moreover, it did not leak even if hot water was circulated in the piping.

[Test 2]
A straight pipe made of hard vinyl chloride resin (outer diameter: 26 mm) is inserted and joined to each joint produced in Test 1 above, and the pressure resistance at this joint is evaluated in the same manner as Test 1 without using a metal band. It was.

  As a result, for any joint, it was confirmed that a pressure resistance of about 0.01 to 0.02 MPa was obtained at the joint. These do not satisfy the pressure resistance required for non-pressure channels (minimum water pressure of about 0.05 MPa), but are easy to install and remove, and water leakage and gardening that does not pose a problem of leaking water. Can be suitably used in cases where a high degree of sealing at the joint is not required, such as a watering pipe or a blind pipe such as an air duct or an electric cable cover.

1,11,21,31,41 Elbow joint 2,22,32 Cheese joint 3 Rib 14, 24, 34, 44 Straight pipe 15 Metal band 46 Socket

Claims (6)

  A molded joint for piping, which is a single molded product made of a single rubber-like elastic body and used in a fixed shape.   The molded joint for piping according to claim 1, wherein the rubber-like elastic body is ethylene propylene diene rubber having a heat resistant temperature of 110 ° C or higher and a durometer hardness of 60 to 80.   The molded joint for piping according to claim 1 or 2, wherein the wall thickness of the receiving port is 3.0 to 10.0 mm.   The molded joint for piping according to any one of claims 1 to 3, wherein two ring-shaped ribs are provided on an outer periphery of the receiving port.   The method for producing a molded joint for piping according to any one of claims 1 to 4, wherein the molding is performed by compression molding or injection molding.   The construction method for a molded joint for piping according to any one of claims 1 to 4, wherein a receiving port of the joint for piping is connected to an end of the pipe and tightened with a metal band.

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