JP3319510B2 - Fittings for polyethylene pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint for polyethylene pipes, and more particularly to a mechanical joining type (mechanical joining) having excellent watertightness and good workability.

[0002]

2. Description of the Related Art Centrifugal cast pipes made of ductile cast iron are mainly used as pipes buried underground to supply tap water or the like. In recent years, plastic pipes have been gradually used not only in the field of water supply pipes but also in the field of gas and sewage, and are attracting attention as inexpensive and safe pipes due to their flexibility. Rigid PVC pipes have been widely used in Japan for a long time as plastic pipes. In the case of forming a conduit with hard vinyl chloride pipes, there are two types of joining methods, one is a TS method, and the other is a rubbering method. The TS method is a so-called bonding method, which is based on the principle that a special adhesive is applied to the insertion port and the receiving port of the pipe, the surface is partially softened and melted, and it is strongly inserted and adhered together. This is a popular construction method.

[0003] Rigid vinyl chloride pipe is a plastic material that has been widely used since the earliest, and is superior in corrosion resistance, light weight, and advantageous in workability as compared with metal, but is suitable as a pipe buried underground. Considering that, when encountering uneven loads such as vibrations and rocking, the flexibility is still insufficient, and when it reaches a certain limit, it suddenly buckles and breaks. It has not completely solved the inherent weakness of pipes. In addition, in recent years, the incineration of PVC waste has frequently been recognized as the main cause of the generation of dioxin, a carcinogen, and voices that raise doubts about the application of the material itself cannot be ignored.

[0004] In recent years, attention has been paid to polyethylene instead of vinyl chloride, and there are signs that it will rapidly spread as a tube material. Polyethylene material is much more flexible and stretchable than PVC material, and it is highly bent and absorbs external force even if a sudden unbalanced load hits the pipeline, and it does not break even if it is crushed 100%. There is a great feature that it has. Therefore, it is recognized that pipelines buried underground in earthquake prone countries like Japan have favorable conditions.

[0005] An electrofusion joint has hitherto been most commonly used for joining polyethylene materials. Polyethylene cannot take the adhesive (TS) method like vinyl chloride as a material characteristic, so a heating wire such as a nichrome wire is embedded in advance near any surface to be joined and the member is injection molded. Aside
When joining, the joining surfaces are overlapped, the surface is locally heated by heating and heating the heating wire, and the joining is performed integrally, which is the mainstream of the current polyethylene material joining.

[0006]

However, the electrofusion method has a problem when it is considered on the premise that a pipeline is laid on site. For example, when it rains, complete joining cannot be performed if water drops adhere to the joint fusion joint. In addition, it is also a fact that there are various problems such as difficulties in repairing a live pipe (a pipe actually passing water) and a lack of reliable sealing of the joint. From such a viewpoint, if a mechanical joining method (mechanical joining) can be applied to polyethylene pipes instead of the electrofusion method, pipelines that require joining and demolition such as construction in rainy weather, repair of live pipes, and temporary pipes It is possible to spread it widely by applying it to construction.

However, in the case of the mechanical joining method, the strength and rigidity inherent to the material with respect to an external force govern the success or failure. In that respect, polyethylene material is 10
Even if the tube is deformed until the top and bottom of the tube are overlapped by 0%, it has a viscosity that it is still ruptured, but on the other hand, if it is subjected to external force, creep deformation starts over time and it adapts to external force Therefore, there is a possibility that the material itself is deformed to weaken the joining force forming the conduit, which is disadvantageous in comparison with other materials. For example, in order to maintain the sealing properties of pipelines, elastic rubber was tightened to suppress water pressure with rubber surface pressure, but there is one side that the rubber surface pressure decreases due to creep deformation of polyethylene and finally there is a concern that water leakage may occur .

[0008] FIG. 5 shows a polyethylene polyethylene flange adapter 102 joined to the end faces of two polyethylene pipes 101 by butt fusion. The flanges 104 on the end faces are brought into contact with each other with a rubber 103 interposed therebetween. This is a typical conventional technique of mechanical joining in which a loose flange 105 made of metal is applied to the outer side surface of 104 and fastened with a bolt and nut 106. In this case, bolt and nut 1 as shown
06, the polyethylene flange 104 undergoes creep deformation, and the rubber 10
The rubber surface pressure of No. 3 is likely to decrease, which may cause water leakage from this portion.

At the same time, in the case of polyethylene pipes, due to the characteristic of this resin, the amount of creep deformation is large, and when used as a buried pipe for a long time, the pipe becomes deformed or flattened due to internal and external pressure, and the rubber pressure on the water-stop surface decreases. In addition, there is a danger of water leakage, and in the case of a mechanical joint using water-stop rubber, since it does not have an integral structure unlike electrofusion joining, it is necessary to add a structure for preventing a pipe joint from coming off due to water pressure or ground displacement.

FIG. 6 shows the prior art of a pipe joint according to Japanese Utility Model Publication No. 58-31035, and Japanese Utility Model Publication No. 56-20634 and Japanese Utility Model Application Publication No.
No. is also found. A receiving port 201A is formed by enlarging the end of the metal pipe joint 201 to a conical tapered surface.
01A of the polyethylene tube 202 to be inserted into the
On the inner peripheral surface of A, a hard reinforcing member 203 is inserted and engaged,
A metal annular pressing member 206 that presses the elastic packing by screwing the elastic packing 204 and the retainer 205 into the hollow space between the receiving ports 201A and 202A and screwing the elastic packing into the hollow space between the receiving ports 201A and 202A. And formed. It is stated that this configuration can sufficiently maintain the sealing function and the retaining function, which have conventionally been problems.

However, although this pipe joint solves various difficulties caused by the electrofusion method,
This is not always ideal in terms of laying underground pipelines. Speaking from the ideal of laying work, one end of the pipe forms a receiving port with an enlarged diameter, another pipe end to be joined is inserted into this receiving port as a straight insertion port, and this process is repeated to make a long pipe line. The reason for this is that the forming method is the most efficient, and the receiving-inserting method of the ductile iron pipe has long been the main component of the pipe joint.

In this prior art, the pipe joint is made of metal,
The rigidity of the receiving port 201A and the metallic annular pressing member 206
Although the surface pressure of the elastic packing 204 is maintained by screwing with it, if the socket itself is made of a polyethylene pipe, the surface pressure may decrease due to the creep deformation inherent to the polyethylene material, and the sealing function may recede. Cannot be denied.
Further, the screwing between the receiving port 201A and the annular pressing member 206 also loses the pressing force due to the deformation, the surface pressure decreases, and the risk of detachment increases. If the pipe diameter increases, the screw connection itself becomes difficult. It is likely to be a serious obstacle to construction.

[0013] As described above, the method of inserting the insertion port of another pipe of the same material into the reception port of a single pipe, which is considered to be the best in the workability of pipe laying, and joining the pipes, that is, basically the current ductile cast iron pipes If the joint method of (1) is also diverted to the joining of polyethylene pipes, the insertion port will undergo creep deformation in the direction of reducing the diameter and the receiving port will expand in the direction of increasing the diameter under the surface pressure of the elastic rubber for sealing. Progresses, the rubber surface pressure decreases with the passage of time, and water may eventually leak. In this case, the significance of replacing with a polyethylene pipe, which is lightweight and excellent in workability, is resistant to corrosion, and does not require complicated corrosion prevention treatment such as metal, may be reduced by half.

In order to solve the above-mentioned problems, the present invention is based on the connection between the inlet and the outlet of polyethylene pipes, and completely wipes out negative elements based on the physical properties inherent to the polyethylene material to achieve sealing properties and prevention of detachment. The purpose is to provide thorough fittings.

[0015]

According to the pipe joint for a polyethylene pipe according to the present invention, a high-rigid insertion port core 22 is attached to an inner peripheral surface 21 of an insertion port 2 of one polyethylene pipe 1A, and the polyethylene pipe 1A is reinforced.
A high-rigidity receiving core 31 having a substantially similar cross-section is integrally reinforced in the enlarged diameter receiving port 3 of another polyethylene pipe 1B, and the outer peripheral surface 23 of the insertion port 2 and the inclined inner circumference of the receiving port 3 are inclined. Face 3
2 is inserted into the annular space formed between the rubber ring 2 and the stopper ring 4 that engages with the outer peripheral surface 23 of the opening, and the rubber ring 5 for sealing that presses the both surfaces 23 and 32 intervenes. A pressing wheel 6 having a leg 61 abutting against an outer side surface 51 of the tube is screwed together with the high-rigidity receiving core 31 and a bolt / nut 7 to separate the tubes and reduce the rubber surface pressure due to creep deformation. This problem has been solved by preventing the above problem.

With this configuration, a joint is formed between the insertion port and the receiving port of the polyethylene pipe, and when the bolts and nuts 7 are tightened, the outer peripheral surface of the inserting port and the inner peripheral surface of the receiving port contact with the sealing rubber ring 5. A rubber surface pressure is generated and a sealing action is generated. The bolt / nut 7 is fastened to the high-rigidity receiving core 31 while the high-rigidity insertion core 22 is attached to the inner peripheral surface of the insertion port to reinforce the main part of the pressure receiving. The creep deformation is prevented and the function to maintain the water stop pressure for a long time is provided. Also,
The detachment preventing claw 4 deposited between the outer peripheral surface of the insertion opening and the inner peripheral surface of the receiving opening is pushed in along the tapered surface via the rubber ring 5 for sealing as the bolt and nut 7 are tightened. Since it engages with the surface, the function of preventing detachment is exhibited.

[0017]

FIG. 1 is a partially longitudinal front view showing an embodiment of the present invention, and shows a polyethylene pipe 1A to be joined.
1B is a standard standard product of a desired diameter which is mass-produced in a factory. The insertion port 2 remains a straight pipe, and the receiving port 3 is formed by separately injection-molding a polyethylene member manufactured in advance and integrally joining the straight pipe with the butt fusion 11. It is desirable that the process be manufactured in a mass production system of a production factory, be on standby as a standard product, and supplied to the laying site as many as required for pipe formation as necessary. For the butt fusion, it is sufficient to apply a known technique of press-fitting the inner and outer surfaces of both members with a heating mold or the like.

The receiving port 3 has a conical shape formed by an inner peripheral surface 32 having an inclined diameter increasing toward the outer end and an annular ridge 33 at the outer end, and has a high rigidity contained in the receiving port 3. The receiving core 31 also includes an inclined surface having the same angle and an annular ridge 34 at the outer end. It is an important requirement that the material of the high-rigidity receiving core be clearly higher rigidity than the base material polyethylene, and steel plates may be formed and processed. A high rigidity special resin to be collected, specifically, a special polyamide resin or a sulfur-containing polymer, more specifically, a molded article such as polyphenylene sulfide may be used. In this regard, the same applies to the high-rigidity insertion core 22 attached to the inner peripheral surface 21 of the insertion opening 2. Regarding the high-rigidity receiving core 31, a molded body of the high-rigidity receiving core is set in a predetermined space in a receiving die for injection molding in advance, and the space is integrally filled with a polyethylene material by injection filling. It can be easily manufactured by the method of inclusion.

The annular ridges 33 and 34 are equally distributed in the circumferential direction, and four to eight holes are drilled to form tap holes 35. It goes without saying that the number of tap holes 35 increases or decreases depending on the diameter of the tube.

The conical annular space formed by the inclined inner peripheral surface 32 of the receiving opening 3 and the outer peripheral surface 23 of the insertion opening is called a stuffing box. Is inserted continuously. The detachment preventing claw 4 is made of a metal or the above-mentioned high-rigidity special resin. As one form of the shape, as shown in FIGS. 2A and 2B, an inclined surface 41 having substantially the same angle as the inner peripheral surface 32 of the receiving port is used. An outer peripheral surface, and a ring-shaped body having a serrated engagement protrusion 42 engraved on the inner peripheral surface side is used for sticking (biasing in a contraction direction). Since it is a split annular body, there is an advantage that the work of fitting onto the outer peripheral surface of the insertion opening is easy.

The sealing rubber ring 5 is made of a well-known elastic rubber having a rounded end face in the stuffing box and a rounded outer face 51, and is harmless even in contact with water. Choose from synthetic rubber that is guaranteed. Pressing ring 6 for pressing leg 61 against outer surface 51 of sealing rubber ring 5
May be made of metal, and economically, a stock product made of ductile cast iron, which has been mass-produced as a standard specification and whose surface is protected with an anticorrosive paint, may be used. Mounting hole 62 for pressing wheel 6
The bolt 71 is screwed into the tap hole 35 provided in the high-rigidity receiving core 31 through which the bolt 71 is inserted, and the nut 72 that is screwed into the bolt 71 from the opposite side of the pressing ring to tighten the pressing ring is also a stock product with anticorrosion coating. It is enough to divert.

3 (A) to 3 (C) are partial longitudinal front views showing the procedure for carrying out the present invention. In FIG. 3 (A), the insertion port 2 has a pressing ring 6 and a sealing rubber ring. 5. Place the release prevention claw 4 on the outer peripheral surface of the highly rigid insertion core 2
2 is mounted on the inner peripheral surface. In FIG. 2 (B), the insertion opening 2 is inserted into the receiving opening 3, the separation preventing claw 4 and the sealing rubber ring 5 are accommodated in the stuffing box, and the leg of the pressing ring 6 is attached to the outer surface 51 of the sealing rubber ring. Apply part 61. Insert the tip of the bolt 71 into the mounting hole 62
And screwed into the tap hole 35 engraved on the high-rigidity receiving core of the receiving port. In FIG. (C), a nut 72 is screwed from the side surface of the press wheel to the rear end of the bolt 71 and tightened to a specified torque to complete the joining.

FIG. 4 shows another embodiment of the present invention which is particularly effective for "separate piping" which occurs at the final stage of laying work. A standard pipe manufactured to a fixed length is cut to the actual length at the final stage. It is often applied when joining straight pipes (insertions). The basic structure is the same as that of the above-mentioned embodiment, and an inward central ridge 81 against which the tips of the insertion openings 2A and 2B of the polyethylene pipes 1A and 1B to be joined hits, and the central ridge 81
A connecting ring type joint 8 made of polyethylene is formed of inner portions 3A and 3B which are enlarged in diameter toward both ends and inclined.
A, 3B, the both ends of the high-rigidity receiving core 31 and the pressing wheels 6A, 6B disposed on both sides thereof are bolts and nuts 7 respectively.
A configuration in which the screws A and 7B are screwed together is desirable.

[0024]

The present invention has a superior corrosion resistance, is lighter in weight, and is easier to transport and construct than ductile cast iron pipes, which conventionally occupy the main part of pipes buried underground for water supply, sewage, gas, etc. Yes, while utilizing the properties of polyethylene pipes that are highly durable against earthquakes and other disasters, the joints between the pipes can be completed only by inserting the insertion port into the receiving port almost in the same way as ductile cast iron pipes Since the method from the receiving port to the insertion port can be used as it is, there is an effect of providing an ideal pipeline through earthquake resistance, workability, and economy. With the use of polyethylene material, the sealing function with the passage of time that does not become the only bottleneck,
The effect of preventing the creep deformation, which is the cause of the decrease in the detachment prevention function, and maintaining the reliability of the pipeline for a long time is most important.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal front view showing an embodiment of the present invention.

FIG. 2 is a side view (A) of the separation preventing claw in the embodiment and an arrow view (B) of an AA cross section in the same figure.

3 (A) to 3 (C) are partial longitudinal front views each showing a procedure of implementing the present invention.

FIG. 4 is a longitudinal sectional front view showing another embodiment of the present invention.

FIG. 5 is a partial sectional front view showing a conventional technique.

FIG. 6 is a vertical sectional front view showing another conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polyethylene pipe 2 Insertion opening 3 Reception opening 4 Separation prevention claw 5 Rubber ring for sealing 6 Pressing ring 7 Bolt and nut 8 Joint type joint 11 Butt fusion 21 Inner peripheral surface 22 High rigidity insertion core 23 Outer peripheral surface 31 High rigidity receiving Mouth core 32 Inner peripheral surface 33 Annular ridge 34 Annular ridge 35 Tap hole 41 Inclined surface 42 Locking projection 51 Outer side 61 Leg 62 Mounting hole 71 Bolt 72 Nut 81 Central ridge

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-159562 (JP, A) JP-A-53-56718 (JP, A) JP-A-7-19379 (JP, A) JP-A-58-58 12712 (JP, A) Japanese Utility Model Showa 61-14288 (JP, U) Japanese Utility Model Showa 64-21891 (JP, U) Japanese Utility Model Utility Model No. 2-16895 (JP, U) (58) Field surveyed (Int. ⁷ , DB name) F16L 21/00-21/08 F16L 47/00

Claims (6)

(57) [Claims] 1. In a pipe joint for joining a polyethylene pipe and a polyethylene pipe to form a pipe, a high-rigid insertion port core 22 is attached to an inner peripheral surface 21 of an insertion port 2 of one of the polyethylene pipes 1A, and is adhered and reinforced. A high-rigidity receiving core 31 having a cross section substantially similar to that of the enlarged diameter form is integrally included in the enlarged diameter receiving port 3 of another polyethylene pipe 1 </ b> B, and the outer peripheral surface 23 of the insertion port 2 and the receiving port 3 are strengthened. Into the annular space formed between the inner peripheral surface 32 and the inclined outer peripheral surface 23.
And a rubber ring 5 for sealing which presses the both surfaces 23 and 32.
And the pressing ring 6 having the leg portion 61 which comes into contact with the outer surface 51 of the sealing rubber ring 5 is screwed and fastened to the high rigidity receiving core 31 via the bolt and nut 7 to connect the pipes to each other. A joint for polyethylene pipes, which prevents detachment and a decrease in rubber surface pressure due to creep deformation. 2. A receiving port 3 including a high-rigidity receiving port core 31 having a truncated conical shape having a substantially similar cross-section and formed separately from a polyethylene material according to claim 1.
6. A joint for polyethylene pipes, characterized in that the pipe 6 and the end face of the polyethylene pipe 1B, which is a straight pipe, are butt-fused, and a polyethylene pipe with a receiving port is integrally mass-produced in advance and is on standby. 3. When both polyethylene pipes 1A and 1B to be joined are "separation pipes" comprising insertion ports 2A and 2B according to claim 1 or 2, the two insertion ports 2 inserted therein.
A central inward ridge 81 against which the tips of A and 2B strike, and a receiving port 3 which is enlarged in diameter from the central ridge 81 to both ends and inclined.
A, 3B polyethylene jointed pipe joint 8
And a high-rigidity receiving core 3 contained in the receiving ports 3A and 3B.
1. A joint for polyethylene pipes, characterized in that both ends of 1 and press wheels 6A, 6B arranged on both sides are screwed together via bolts and nuts 7A, 7B. 4. An inner peripheral surface 32 of a receiving port 3 according to claim 1, wherein the inner peripheral surface 32 is formed as a substantially frustoconical inclined surface, and an annular ridge 33 is protruded at an outer end thereof. The high-rigidity receiving core 31 to be provided also has an inclined surface at the same angle and an annular ridge 34 at the outer end,
The tip of a bolt 71 commonly inserted into a predetermined number of tap holes 35 equally dividing the circumference of the annular ridges 33 and 34 and a mounting hole 62 drilled at a corresponding position on the circumference of the pressing ring 6. A joint for a polyethylene pipe, wherein the joint is screwed into the tap hole 35, and the rear end of the bolt 71 is tightened by a nut 72 from the outer surface of the pressing ring and is engaged with a predetermined torque. 5. The high-rigidity insertion core 22 and the high-rigidity receiving core 31 according to claim 1,
Or a joint for polyethylene pipes, characterized in that both are formed of metal or high rigidity special resin. 6. The detachment preventing claw 4 according to claim 1, wherein an inclined surface 41 having substantially the same angle as an inner peripheral surface 32 of the receiving port 3 is an outer peripheral surface, and a serrated bite is formed on the inner peripheral surface side. A fitting for a polyethylene pipe, comprising a ring made of metal or a high-rigidity special resin, which is attached to the outer peripheral surface of the insertion opening in a divided manner in which the stop projection 42 is engraved and is urged in a direction in which it shrinks freely. .