JP2009085334A - Synthetic resin double pipe and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synthetic resin pipe having a double structure of an inner pipe and an outer pipe and having flexibility and excellent compressive strength by structuring the inner pipe with an olefin-based resin and by forming a part of the outer pipe with reinforcing spiral ridges made of a hard vinyl chloride resin having no adhesive property to the inner pipe, and to make it possible to adhere a short pipe for joining having no adhesive property to the olefin-based resin on the outside circumferential surface of the cut edges even when the pipe is cut at an arbitrary part. <P>SOLUTION: In this double pipe made of a synthetic resin, the reinforcing spiral ridges 3 made of the hard vinyl chloride resin are wound on the outside circumferential surface of the inner pipe 1 made of the olefin-based resin. A soft resin filler 4 made of the olefin-based resin fused integrally with the inner pipe 1 is filled in the spiral grooves 5 between the winding pitches of the reinforcing spiral ridges 3 to prevent the ridges 3 from being frayed or separated. The adhesion of the short pipe for joining is made possible by forming the outer pipe 2 whose outside circumferential surface continues flush with the ridges 3 over the total length. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a long synthetic resin double pipe used as a drain pipe and other pipes and a method for producing the same.

  Conventionally, as a flexible synthetic resin pipe used for drain pipes and drain hoses, etc., pipes made of soft vinyl chloride resin that are inexpensive and suitable for mass production have been used. By connecting the short pipes for joints made of the same material together with an adhesive, the pipes are connected to each other or the pipes are connected to a water supply port or the like. Because it is made of vinyl chloride resin, its pressure resistance is weak, and when external pressure is applied in the radial direction, it can be easily crushed and smooth drainage cannot be performed. There is a problem that smooth distribution is hindered in a bent state.

  For this reason, for example, as described in Patent Document 1, a reinforcing spiral protrusion such as a hard vinyl chloride resin is formed on the outer peripheral surface of a flexible synthetic resin hose mainly made of an olefin resin or a soft vinyl chloride resin. Wound strips are used to give pressure resistant strength to the synthetic resin hose main body by this reinforcing spiral protrusion, and both ends of the hose main body are smooth surfaces with the same synthetic resin as the hose main body. Synthetic resin hoses have been developed which are formed in a connection port portion having a certain thickness formed in the above.

JP 2002-286172 A

  However, according to the synthetic resin hose, if the hose main body is made of soft vinyl chloride resin, a large amount of dioxin is generated when incinerated, causing environmental pollution and having a poor service life due to poor weather resistance. In addition, the plasticizer contained in the inside may shift and cause harmful effects.

  Such a problem can be solved when the hose is mainly formed of an olefin resin such as polyethylene or polypropylene. However, since the olefin resin has poor adhesiveness, the olefin resin has flexibility. When the hose main body is formed, the reinforcing spiral ridge made of hard vinyl chloride resin cannot be fused to the outer peripheral surface thereof. Therefore, in this synthetic resin hose, the reinforcing spiral ridge is integrated with the hose main body. It is necessary to coat with a coating layer made of an olefin-based resin that has been fused, and not only labor is required for production, but if the coating layer is torn, there is a possibility that the reinforcing spiral ridges may pop out.

  Furthermore, the major problem of the synthetic resin hose in which the reinforcing spiral ridge is wound around the outer peripheral surface of the hose main body as described above is that the joint short pipe made of hard vinyl chloride resin or the like is made of another vinyl chloride resin. When connecting to a hose or pipe or connecting to a water supply port, etc., for example, the hose main body is formed of a soft vinyl chloride resin, and the outer surface of the hose main body is made of a hard vinyl chloride resin. The hose is cut to a predetermined length and one half of the joint short pipe is fitted on the reinforcing spiral ridge protruding from the outer periphery of the hose end. When fixed, when the water flowing through the hose flows through the connecting portion between the hose end connected by the joint short pipe and the other pipe body, these hose end faces and the end faces of the pipe bodies, etc. The inside of the short pipe for joints from between the end faces It will leak to the outside along the spiral groove between the reinforcing spiral ridges in contact with the surface.

  For this reason, in the synthetic resin hose provided with the reinforcing spiral ridges on the outer peripheral surface, it cannot be used after being cut to a desired length. There is a problem that the range of use is greatly limited because it must be used as a structure of a standard hose provided with a connection port portion having a constant thickness formed on a smooth surface.

  The present invention has been made in view of such problems, and the object of the present invention is to provide a connection port having smooth inner and outer peripheral surfaces at both ends, despite the provision of reinforcing spiral protrusions on the outer peripheral surface. Even if it is cut from any part, it can be firmly attached in a state where the inner peripheral surface of the joint short pipe is completely tightly fitted to the outer peripheral surface of the cut end portion without providing a portion or the like. An object of the present invention is to provide a synthetic resin double tube having excellent pressure resistance and moderate flexibility, and a method for producing the same.

  In order to achieve the above object, the synthetic resin double pipe of the present invention is made of a hard vinyl chloride resin on the outer peripheral surface of a flexible inner pipe made of an olefin-based resin as described in claim 1. Reinforced spiral ridges are wound at a constant pitch, and a soft resin filler made of an olefin resin is filled in a spiral groove formed between the winding pitches of the reinforced spiral ridges. The inner peripheral surface of the soft resin filler is integrally fused to the outer peripheral surface of the inner tube, and the reinforcing spiral protrusion is held detachably from the inner tube by the soft resin filler. The outer peripheral surface of the reinforcing spiral ridge and the soft resin filler are made to be flush with each other in the length direction of the pipe, and the outer spiral surface and the soft resin filler form an outer tube with a smooth outer peripheral surface. The outer tube and the inner tube constitute a double tube To have.

  In the synthetic resin double pipe constructed as above, the invention according to claim 2 is characterized in that the reinforcing spiral ridge made of the hard vinyl chloride resin is provided with stepped locking surfaces or inclined locking surfaces at both ends thereof. On the other hand, on both end surfaces of the soft resin filler made of olefin-based resin, a locking surface is formed on the locking surface so as to overlap with each other. It is characterized by.

  On the other hand, in the invention according to claim 3, both end surfaces of the reinforcing spiral protrusion made of the hard vinyl chloride resin are formed on the concave and convex engaging surfaces, while both end surfaces of the soft resin filler made of the olefin resin are formed on the both end surfaces. It is formed in the uneven | corrugated locking surface engaged with an uneven | corrugated locking surface. The invention according to claim 4 is characterized in that the central part of the reinforcing spiral protrusion is formed in a hollow part having an opening part opened toward the outer peripheral surface of the inner tube.

  The invention according to claim 5 is a method for producing the above synthetic resin double pipe, comprising a soft synthetic resin strip made of a semi-molten olefin resin having a constant width and a constant thickness on a molding rotating shaft. By spirally winding, a flexible inner tube having a certain thickness is formed, and a hard synthetic resin string material made of a hard vinyl chloride resin in a semi-molten state is formed at a certain pitch on the outer peripheral surface of the inner tube. Reinforcing spiral ridges are formed by spirally winding, and further semi-molten in a spiral groove between the previously wound reinforcing spiral ridge and the next wound reinforcing spiral ridge. Supplying and filling a string-like soft resin filler made of an olefin resin in a state, and exposing the bottom surface of the soft resin filler to the outer circumferential surface of the inner pipe exposed in the spiral groove between the reinforcing spiral protrusions The top surface of the soft resin filler is reinforced spirally and fused together. By molding so as to continue to the top surface and flush with, and providing a outer tube to the outer circumferential surface of the inner tube consisting of the reinforcing spiral ridge and a soft resin filler.

  In the method of manufacturing a synthetic resin double pipe having the above-described configuration, the invention according to claim 6 includes a reinforcing spiral protrusion made of a hard vinyl chloride resin in a semi-molten state and stepped locking surfaces at both ends thereof. Or, while being formed into a cross-section convex shape or trapezoidal shape having an inclined locking surface, a reinforcing spiral ridge portion wound first on the outer peripheral surface of the inner tube and a reinforcing spiral ridge portion wound next The cord-like soft resin filler made of a semi-molten olefin resin to be supplied and filled in the spiral groove is supplied to the spiral groove and then protrudes from the spiral groove. Are leveled so as to be flush with the top surface of the reinforcing spiral ridge by a leveling roller that rotates in contact with the flat top surface of the reinforcing spiral ridge, and the adjacent reinforcing spiral in the spiral groove. It is plastically deformed in contact with the opposing surface of the ridge, and is filled into the spiral groove. Characterized in that it is fused integrally with the outer peripheral surface of the inner tube bottom consisting of olefin resin.

  In the invention according to claim 7, the reinforcing spiral ridge made of the semi-molten hard vinyl chloride resin has a concavo-convex locking surface at both end surfaces and a top surface formed into a flat surface. From a semi-molten olefin-based resin that is supplied and filled into a spiral groove between a reinforcing spiral ridge wound first on the outer peripheral surface of the inner tube and a reinforcing spiral ridge wound next. After the string-like soft resin filler is supplied and filled into the spiral groove, the top protruding from the spiral groove is rotated by a leveling roller that rotates in contact with the flat top surface of the reinforcing spiral ridge. It is leveled so that it is flush with the top surface of the reinforcing spiral ridge, and in the spiral groove, it is plastically deformed in contact with the opposing concave and convex engaging surfaces of the adjacent reinforcing spiral ridges, and spirals. Integrated into the outer circumferential surface of the inner tube made of olefin resin and filled in the groove Characterized in that it is fused.

  According to the first aspect of the invention, a flexible inner tube made of an olefin resin, a reinforcing spiral ridge made of a hard vinyl chloride resin spirally wound around the outer peripheral surface of the inner tube, and the reinforced spiral ridge. A synthetic resin double pipe whose outer peripheral surface is smooth over the entire length from the outer pipe formed by the soft resin filler filled in the spiral groove formed between the winding pitches of Therefore, it is possible to give a crushing strength over the entire length by a reinforcing spiral protrusion made of hard vinyl chloride resin, and it maintains a circular cross section without deforming into a flat shape even if it is curved, and has a good drainage function As a matter of course, the outer peripheral surface of the cut end portion can be cut from any portion in the length direction, and the reinforcing spiral protrusion made of hard vinyl chloride resin and the soft resin filler made of olefin resin And each other Since there is a continuous top surface in the same shape, when one half of the joint short pipe made of hard vinyl chloride resin is connected to this pipe end to connect with other pipes, etc. In addition, the inner peripheral surface of the reinforcing spiral ridge made of a hard vinyl chloride resin can be securely bonded to the top surface of the reinforcing spiral ridge by an adhesive, and the reinforcing spiral ridge that is continuous in a flush manner. The inner peripheral surface of the joint short pipe can be brought into close contact with the outer peripheral surface of the end of the pipe formed by the top surface of the resin and the soft resin filler, thereby reliably preventing the occurrence of water leaks. it can.

  Furthermore, since the inner pipe is made of an olefin resin, it can be used for a long time without causing any adverse effects due to the plasticizer, and is spirally wound around the outer peripheral surface of the inner pipe made of the olefin resin. The above-mentioned reinforcing spiral ridge made of a hard vinyl chloride resin is a soft material filled in a spiral groove formed between the winding pitches of this reinforcing spiral ridge, despite being non-adhesive with an olefin resin. The resin filler is made of an olefin resin, and the inner peripheral surface thereof is integrally fused to the outer peripheral surface of the inner tube made of olefin resin, and the reinforcing spiral ridges are formed inside by the soft resin filler. Since it is held so that it cannot be detached from the pipe, there is no risk that the reinforcing spiral protrusion will fray from the cut end even if the pipe is cut from the desired length, and it is always fixed on the inner pipe. Holding the exact double pipe structure, it is possible to construction with an excellent handling property provides easy plastic double tube.

  Further, the inner tube of the synthetic resin double tube is made of a flexible olefin resin as described above, and the outer tube is made of a reinforcing spiral ridge made of a hard vinyl chloride resin and the reinforced spiral ridge. Since it is made of a soft resin filler made of non-adhesive olefin resin, when it is bent, the soft resin filler made of olefin resin is pinched by the reinforcing spiral protrusions and compressed in the inner curved portion. On the other hand, in the outer curved portion, the reinforcing spiral ridge made of hard vinyl chloride resin and the reinforcing spiral ridge move in the direction in which the joint surface between the non-adhesive soft resin filler made of olefin resin is separated. Can be bent uniformly over the entire length, and therefore can be wound around a drum or the like although it has a relatively large diameter. Can be left by winding the tube can be via a joint tube or the like is cut to the desired length as described above to connect easily and securely to other piping during installation.

  According to the second aspect of the present invention, the reinforcing spiral ridge made of hard vinyl chloride resin is formed in a cross-sectional convex shape or trapezoidal shape having stepped locking surfaces or inclined locking surfaces at both ends thereof. On the other hand, since the soft resin filler made of olefin resin is formed on the engaging surface that is engaged with the both end surfaces in an overlapping manner on the engaging surface, the inner pipe made of olefin resin is formed. A soft resin filler made of an olefin resin that is integrally fused to the outer peripheral surface of the inner tube even though the inner peripheral surface of the reinforcing spiral protrusion made of hard vinyl chloride resin is not bonded to the outer peripheral surface. Since the locking surface is locked on the locking surface of the reinforcing spiral ridge, it is possible to reliably prevent the reinforcing spiral ridge from fraying or detaching from the end side of the tube. The outer surface of the outer tube is flush with the top surface of the ridge and the soft resin filler. It is possible to be formed.

  Furthermore, according to the invention of claim 3, while both end surfaces of the reinforcing spiral protrusion made of hard vinyl chloride resin are formed on the concave and convex engaging surfaces, both end surfaces of the soft resin filler made of olefin resin are formed. Since it is formed on the uneven engagement surface that engages with this uneven engagement surface, the uneven engagement surface provided on the side end surface of the soft resin filler integral with the inner tube and the inner tube are not bonded to each other. As in the case of claim 2 above, it is ensured that the reinforcing spiral ridge is frayed or detached from the inner tube by the engagement with the concave and convex engaging surface provided on the opposite end face of the reinforcing spiral ridge made of vinyl chloride resin. Can be prevented.

  Further, according to the invention according to claim 4, since the central portion of the reinforcing spiral ridge made of the hard vinyl chloride resin is formed in the hollow portion having an opening opened toward the outer peripheral surface of the inner tube, Of course, when the tube is bent, the reinforcing spiral ridge can expand or contract the opening width of the opening according to the degree of bending. The bendability of the double pipe is further improved, and the handleability and workability can be improved.

  The invention according to claim 5 is a method for producing the above synthetic resin double pipe, in which a flexible synthetic resin strip-like material made of a semi-molten olefin resin having a constant width and a constant thickness is spirally wound on a rotating shaft. As a result, a flexible inner tube having a certain thickness is formed, and a hard synthetic resin string material made of a semi-molten hard vinyl chloride resin is spirally formed at a constant pitch on the outer peripheral surface of the inner tube. A reinforced spiral ridge is formed by winding, and a semi-molten olefin is formed in a spiral groove between the previously wound reinforcing spiral ridge and the next wound reinforcing spiral ridge. By supplying and filling a string-like soft resin filler made of a resin, an outer tube is formed by these reinforcing spiral protrusions and the soft resin filler, so that an inner tube is formed on the inner tube. The outer tube can be formed continuously and limited in length It can be manufactured with good efficiency the Rukoto without long plastic double tube.

  Furthermore, on the outer peripheral surface of the inner tube formed on the molding rotating shaft, the above-mentioned half-way is inserted in the spiral groove between the previously wound reinforcing spiral ridge and the next wound reinforcing spiral ridge. Supplyed and filled with a string-like soft resin filler made of a molten olefin resin, and made of the olefin resin in which the bottom surface of the soft resin filler is exposed in the spiral groove between the reinforcing spiral protrusions An inner tube made of an olefin resin is formed by fusing the outer surface of the inner tube integrally with the top surface of the soft resin filler so as to be continuous with the top surface of the reinforcing spiral protrusion. The reinforcing spiral ridge wound on the inside of the spiral groove formed by the space between the winding pitches of the reinforcing spiral ridge, despite being formed of a hard vinyl chloride resin that is non-adhesive to the olefin resin. Olefin resin filled in and fused to the inner tube The soft resin filler can maintain the state of being accurately spirally wound on the inner tube, and the reinforcing spiral protrusion and the soft resin filler can be closely in contact with each other without any gap between the opposing side surfaces. In this state, it is possible to accurately and smoothly form an outer tube having a constant thickness in which the outer peripheral surface is formed in a smooth surface having the same diameter over the entire length continuously in the length direction of the tube.

  Further, in the above method for producing a synthetic resin double pipe, the invention according to claim 6 is characterized in that stepped portions are formed at both ends of the reinforcing spiral protrusion made of a semi-molten hard vinyl chloride resin spirally wound on the inner pipe. While the locking surface or the inclined locking surface is formed, the string-like soft resin filler made of a semi-molten olefin resin is formed in the spiral groove formed between the winding pitches of the reinforcing spiral protrusions. Since the top portion protruding from the spiral groove is pressed by a rotating leveling roller in contact with the flat top surface of the reinforcing spiral protrusion, the top surface of the soft resin filler is pressed against the reinforcing spiral protrusion. It can be leveled so that it is flush with the top surface of the strip, and in the spiral groove, the soft resin filler is plastically deformed in contact with the opposing end surface of the reinforcing spiral ridge adjacent to the spiral groove. Fills the groove, and after curing, both ends of the reinforcing spiral ridge It may have been undetachable retained on the inner tube a reinforcement spiral ridge to form a surface which engages on the locking surface.

  According to the seventh aspect of the invention, in place of the reinforcing spiral protrusions according to the sixth aspect in which stepped locking surfaces or inclined locking surfaces are formed at both ends, an uneven surface is provided on both end surfaces. A reinforcing spiral ridge having a stop surface and a top surface formed into a flat surface is used, and a semi-molten state is formed in a spiral groove formed on the inner tube by the winding pitch of the reinforcing spiral ridge. Supplying, filling, and filling the string-like soft resin filler made of the olefin-based resin with a leveling roller that rotates in contact with the flat top surface of the reinforcing spiral protrusion, Similarly to the sixth aspect, the top surface of the soft resin filler can be leveled so as to be flush with the top surface of the reinforcing spiral protrusion, and the soft resin filler is adjacent in the spiral groove. Touch the opposite end face of the reinforced spiral ridge and plastically deform to fill the spiral groove, after curing It can be held in the irremovably to the inner tube on the both end portions uneven fitting face formed to reinforce the spiral ridge of the engaged with the uneven fitting faces of the reinforcement spiral ridge.

  Next, a specific embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a part of a synthetic resin double tube, and FIG. The inner tube 1 having a certain thickness made of an olefin-based resin such as polyethylene or polypropylene having a property and the outer peripheral surface integrally provided on the inner tube 1 are formed on a smooth surface having the same diameter over the entire length. The outer tube 2 has a constant thickness, and the outer tube 2 includes a reinforcing spiral protrusion 3 made of a hard vinyl chloride resin and wound around the outer peripheral surface of the inner tube 1 at a constant pitch. Between the winding pitches of the reinforcing spiral ridges 3, that is, in the spiral grooves 5 between the reinforcing spiral ridges wound around the outer peripheral surface of the inner tube 1 and the reinforcing spiral ridges wound next. It is made of an olefin resin formed by filling the spiral groove 5 so as to be buried throughout. It is formed of a soft resin filler 4.

  The groove bottom surface of the spiral groove 5 is formed by the outer peripheral surface of the inner tube 1, and the soft resin filler 4 filled in the spiral groove 5 is made of an olefin resin made of the same material as the inner tube 1. Therefore, the inner peripheral surface (bottom surface) of the soft resin filler 4 is fused to the outer peripheral surface of the inner tube 1 by supplying and filling the soft resin filler in a semi-molten state into the spiral groove 5 at the time of manufacture. Thus, the inner tube 1 and the soft resin filler 4 are integrated, and the spiral groove 5 is entirely filled to have the same cross-sectional shape as the spiral groove 5.

  Although the cross-sectional shape of the reinforcing spiral ridge 3 forming the outer tube 2 together with the soft resin filler 4 is not particularly limited, the reinforcing spiral ridge 3 is non-adhesive with the inner tube 1 made of an olefin resin. Therefore, the reinforcing spiral protrusion 3 cannot be detached from the inner tube 1 in the unwinding direction on the inner tube 1 by the soft resin filler 4 integrally fused to the outer peripheral surface of the inner tube 1. It is formed in a cross-sectional shape that can be held.

  As the cross-sectional shape of such a reinforcing spiral ridge 3, the one shown in FIG. 1 and FIG. 2 is formed in a convex shape with a top surface 3a formed on a flat surface and having a constant thickness. The end surfaces are L-shaped locking surfaces 3b and 3b. Therefore, the cross-sectional shape of the soft resin filler 4 filled in the spiral groove 5 between the reinforcing spiral protrusions adjacent to each other in the length direction of the tube is an inverted convex shape in which the reinforcing spiral protrusion 3 is inverted. The bottom surface is fused to the outer peripheral surface of the inner tube 1 and both end surfaces are locked on the L-shaped locking surface 3b of the reinforcing spiral ridge 3 in an overlapping manner. It is formed on the L-shaped locking surfaces 4b, 4b to prevent the reinforcing spiral protrusion 3 from fraying or detaching in the rewinding direction from the inner tube 1, and the soft resin filler 4 is provided with a reinforcing spiral protrusion. The flat top surface 4 a is formed in the same thickness as the strip 3, and the flat top surface 4 a is continuous with the top surface 3 a of the reinforcing spiral protrusion 3 in a flush manner.

  When the synthetic resin double pipe configured as described above is curved, a compressive force is generated in the inner curved portion, and the soft resin filler 4 made of olefin resin is reinforced by the reinforcing spiral ridge 3 made of hard vinyl chloride resin. The reinforcing spiral ridge 3 is compressed while being pressed and compressed in the width direction, and a tensile force is generated in the outer curved portion, and the opposed end surfaces joined to each other are simply in close contact with each other without being bonded together. And the soft resin filler 4 move away from each other and can be easily bent with a uniform bending radius, and a long synthetic resin double pipe is wound around a drum or the like. be able to.

  In addition, when this long synthetic resin double pipe is cut to a desired length at the time of piping construction, a reinforcing spiral made of hard polyvinyl chloride resin spirally wound on the inner pipe 1 made of olefin resin. Although the ridge 3 is not bonded to the inner tube 1 integrally, the soft resin filler 4 made of olefin resin that forms the outer tube 2 together with the reinforcing spiral ridge 3 is made of the same material. Since it is integrally fused to the outer peripheral surface of the inner tube 1 and the inwardly engaging surface 4b is engaged with the engaging surface 3b of the reinforcing spiral protrusion 3 in an overlapping state, the reinforcing spiral The ridge 3 can always maintain the tube end portion in which the outer peripheral surface forms a smooth continuous surface in the circumferential direction and the length direction together with the soft resin filler 4 without fraying. Cover the pipe end with a joint pipe or joint member made of resin or the like with an adhesive. By fitting, this adhesive is bonded to the outer peripheral surface of the hard vinyl chloride resin reinforced spiral ridge 3 that is spirally exposed at the end of the pipe, and the joint pipe and joint member can be easily and firmly bonded to the double pipe. It can be attached to the end of the pipe and piping work can be performed efficiently.

  In the above embodiment, the inner tube 1 made of an olefin resin and the reinforcing spiral ridge 3 made of a non-adhering hard vinyl chloride resin are formed in a convex cross section and formed on both end faces thereof. The surfaces 3b and 3b are brought into an engaged state in which they are pressed by locking surfaces 4b formed on both end surfaces of the soft resin filler 4 having an inverted cross-sectional convex shape that is a cross-sectional shape of the reinforcing spiral protrusion 3 reversed. The reinforcing spiral protrusion 3 is prevented from fraying or detaching from the inner tube 1, but the structure for preventing the reinforcing spiral protrusion 3 from being frayed by the soft resin filler 4 integral with the inner tube 1 is other than the above. For example, as shown in FIG. 3, the reinforcing spiral ridge 3 is formed in a trapezoidal cross section and its inclined surfaces are inclined locking surfaces 3b and 3b. The cross-sectional shape of the resin filler 4 is formed into an inverted trapezoid shape in which the reinforcing spiral protrusion 3 is inverted. Further, the both-end inclined locking surfaces 4b formed obliquely downward (inward) of the lever may be joined and locked to the inclined locking surfaces 3b of the reinforcing spiral ridges 3.

  Further, as shown in FIG. 4, the upper and lower surfaces (inner and outer surfaces) of the reinforcing spiral ridge 3 are formed as flat surfaces having substantially the same width, and both end surfaces are bent in a zigzag shape in the thickness direction (vertical direction). While forming on the stop surfaces 3b, 3b, the soft resin filler 4 has the same thickness as the reinforcing spiral ridge 3, and the upper and lower surfaces (inner and outer surfaces) are formed as flat surfaces having substantially the same width, and both end surfaces Is formed on the concave and convex engaging surfaces 4b and 4b that can be engaged with the concave and convex engaging surfaces 3b of the reinforcing spiral protrusion 3 in the thickness direction (vertical direction), and by engaging these concave and convex engaging surfaces 3b and 4b The inner tube 1 and the non-adhesive reinforcing spiral ridge 3 may be prevented from being frayed or detached from the outer peripheral surface of the inner tube 1.

  Further, as shown in FIG. 5, the reinforcing spiral ridge 3 is formed in a convex shape in cross section, and through holes 3c are formed at both ends of the reinforcing spiral ridge 3 so as to pass between the upper and lower surfaces. As shown in FIG. 6, the other end surface of the reinforcing spiral ridge portion wound next to one end surface of the reinforcing spiral ridge portion previously wound around the outer peripheral surface of the wire is spirally wound, and this A portion of the inner layer portion of the soft resin filler is supplied by filling and filling the spiral groove 5 formed by the spiral winding of the reinforcing spiral protrusion 3 with a string-like soft resin filler made of a semi-molten olefin resin. Is filled in the through hole 3c of the reinforcing spiral ridge 3 and is fused to the outer peripheral surface of the inner tube 1 through the through hole 3c, whereby the reinforced spiral ridge made of hard polyvinyl chloride resin is formed by the soft resin filler 4. 3 prevents fraying or detachment from the outer peripheral surface of the inner tube 1 made of olefin resin. And, and, it may have been with these reinforcing spiral ridge 3 and the soft resin filler 4 and the outer circumferential surface by the formed the outer tube 2 formed on one form of smooth surface foliation. The through hole 3c is not limited to a circular hole but may be a long hole.

  Furthermore, although all of the reinforcing spiral ridges 3 have a solid structure, for example, in the reinforcing spiral ridge 3 formed in a convex shape with a cross-sectional shape, as shown in FIG. You may form in the hollow part 3d which has the opening part opened toward the outer peripheral surface of the inner tube 1, and if such a hollow part 3d is provided, the inside which consists of a flexible olefin resin will be provided. When the synthetic resin double pipe formed by forming the outer pipe 2 composed of the reinforcing spiral protrusion 3 and the soft resin filler 4 on the outer peripheral surface of the pipe 1 is curved, the hollow portion of the reinforcing spiral protrusion 3 is formed. 3d expands and contracts in the width direction and can exhibit excellent bendability.

  Next, the manufacturing method of the synthetic resin double pipe constructed as described above will be briefly described with reference to FIG. 8. First, a strip 11 made of a semi-molten olefin resin having a constant width and a constant thickness. As is well known, the opposite side portion (the other half portion) of the following belt-like material portion is placed on one side portion (one half portion) of the preceding belt-like material portion on the molding rotating shaft 20 as is well known. An inner tube 1 having an inner diameter of the same diameter and a constant thickness is formed over the entire length by spirally winding at a constant pitch while being overlapped and fused together. Following the strip 11 made of the olefin resin to be formed, a string-like material 13 made of a semi-molten hard vinyl chloride resin formed into a convex cross section is extruded from the second molding nozzle 22 to Winding spirally around the outer surface with a constant pitch And by forming the reinforcing spiral ridge 3. By forming the reinforcing spiral ridge 3, the reinforcing spiral ridge 3 ′ spirally wound on the inner tube 1 first and the reinforced spiral ridge 3 ′ wound spirally next are formed. A spiral groove 5 is formed continuously.

  Further, the cord-like material 13 made of a semi-molten hard vinyl chloride resin from the second molding nozzle 22 for forming the reinforcing spiral ridge 3 is spirally wound around the inner tube 1. Then, a string-like material 14 made of a semi-molten olefin resin is extruded from the third molding nozzle 23 and this string-like material 14 is supplied to the spiral groove 5 formed between the winding pitches of the reinforcing spiral ridges 3. The top of the cord-like material 14 that is filled and protrudes from the spiral groove 5 is pressed by a leveling roller 24 that rotates in contact with the top surface of the reinforcing spiral ridge 3 to plastically deform the cord-like material 14. However, a soft resin filler 4 having the same cross-sectional shape as the spiral groove 5 is formed by completely filling the spiral groove 5, and the top surface 4a of the soft resin filler 4 made of olefin resin is reinforced. The spiral ridge 3 is formed to be flush with the top surface 3a and the bottom surface is It is integrated with the inner tube 1 by being pressed against the outer peripheral surface of the inner tube 1 made of an olefin resin exposed between the reinforcing spiral ridges 3 ′ and 3 ′ that are in contact with the outer tube and cooled in this state. By doing so, a synthetic resin double pipe is manufactured in which the outer pipe 2 made of the reinforcing spiral protrusion 3 and the soft resin filler 4 is integrally provided on the outer peripheral surface of the inner pipe 1 made of the olefin resin. is there.

  In the method of manufacturing the synthetic resin double pipe, the reinforcing spiral protrusion 3 having a convex cross section is spirally wound on the inner pipe 1, but the reinforcing spiral protrusion having a trapezoidal cross section shown in FIG. The same manufacturing is applied to the reinforcing spiral ridge 3 provided with the concave and convex engaging surfaces 3b, 3b on both sides shown in FIG. 3 and FIG. 4, and further to the reinforcing spiral ridge 3 shown in FIGS. A synthetic resin double pipe using these reinforced spiral ridges 3 can be manufactured by a method. Further, a reinforcing spiral ridge 3 made of a hard vinyl chloride resin is spirally wound on the inner tube 1 made of an olefin resin formed on the molding rotating shaft 20, and the reinforcing spiral ridge 31 and the next wound are wound next. The top of the string-like soft resin filler 4 made of a semi-molten olefin resin to be supplied and filled in the spiral groove 5 between the reinforcing spiral protrusion 31 wound around the above-mentioned smoothing roller 24 is provided. When the top surface 4a of the soft resin filler 4 is formed so as to be flush with the top surface 3a of the reinforcing spiral ridge 3, the doctor knife (not shown) is used together with the leveling roller 24. The excess soft resin filler 4 may be scraped off and the outer peripheral surface of the outer tube 2 may be molded to be a smooth surface.

The side view which carried out the cross section of a part of this invention synthetic resin double pipe. The partially expanded vertical side view. The one part vertical side view which shows the modification of an outer tube | pipe structure. The one part vertical side view which shows another modification of an outer tube | pipe structure. The perspective view which shows the modification of a reinforcement spiral protrusion. The vertical side view of the outer tube part formed with this reinforcement spiral protrusion and the soft resin filler. The partial vertical side view which shows another modification of an outer tube | pipe structure. The simplified side view which carried out the cross section of a part for demonstrating a manufacturing method.

Explanation of symbols

1 Inner pipe 2 Outer pipe 3 Reinforcing spiral ridge
3a Top surface
3b Locking surface 4 Soft resin filler
4a Top surface
4b Locking surface 5 Spiral groove

Claims (7)

  Reinforced spiral ridges made of hard vinyl chloride resin are wound around the outer peripheral surface of a flexible inner tube made of olefin resin at a constant pitch and formed by the winding pitch of the reinforced spiral ridges. A soft resin filler made of an olefin resin is embedded in the spiral groove, and the inner peripheral surface of the soft resin filler is integrally fused to the outer peripheral surface of the inner tube. The reinforcing spiral ridge is held in a non-detachable manner from the inner tube by the resin filler, and the outer peripheral surface of the reinforcing spiral ridge and the soft resin filler is continuously flush with the length of the tube. A synthetic resin double pipe characterized in that an outer pipe having a smooth outer peripheral surface is formed by these reinforcing spiral protrusions and a soft resin filler.   Reinforcing spiral ridges made of hard vinyl chloride resin are formed in a convex or trapezoidal cross section with stepped locking surfaces or inclined locking surfaces at both ends, while soft resin fillers made of olefinic resins 2. The synthetic resin double pipe according to claim 1, wherein both end surfaces are formed on a locking surface that is engaged with the locking surface in an overlapping manner.   Both ends of the reinforcing spiral ridge made of hard vinyl chloride resin are formed on the concave and convex engaging surface, while the concave and convex engaging that engages both ends of the soft resin filler made of olefin resin with the concave and convex engaging surface. It forms in the surface, The synthetic resin double pipe of Claim 1 characterized by the above-mentioned.   4. The synthetic spiral ridge according to claim 1, wherein the reinforcing spiral ridge is formed in a hollow portion having an opening opened at a central portion thereof toward an outer peripheral surface of the inner tube. Resin double tube.   A flexible synthetic resin strip made of a semi-molten olefin-based resin having a constant width and a constant thickness is spirally wound on the rotating shaft of the molding to form a flexible inner tube having a constant thickness. Reinforced spiral ridges are formed by winding a hard synthetic resin string-like material made of hard polyvinyl chloride resin in a semi-molten state at a constant pitch on the outer peripheral surface of the inner tube, and then winding it first. A string-like soft resin filler made of a semi-molten olefin resin is supplied and filled in a spiral groove between the reinforced spiral ridge and the next reinforced spiral ridge. The bottom surface of the resin filler is integrally fused to the outer peripheral surface of the inner pipe exposed in the spiral groove between the reinforcing spiral ridges, and the top surface of the soft resin filler is connected to the top surface of the reinforcing spiral ridge. By forming it so that it is flush with the surface, Reinforcing spiral ridge and method for producing synthetic resin double tube, characterized in that providing an outer tube made of a soft resin filler.   Reinforcing spiral ridges made of semi-molten hard polyvinyl chloride resin are formed into a convex or trapezoidal cross section with stepped or inclined locking surfaces at both ends, while the outer circumference of the inner tube A string-like soft material made of a semi-molten olefin resin that is supplied and filled in a spiral groove between a reinforcing spiral ridge wound first on a surface and a reinforcing spiral ridge wound next. After the resin filler is supplied and filled into the spiral groove, the top of the reinforcing spiral ridge is rotated by a leveling roller that rotates with the top protruding from the spiral groove in contact with the flat top surface of the reinforcing spiral ridge. It is leveled so that it is flush with the surface, and in the spiral groove, it is plastically deformed in contact with the opposing surface of the adjacent reinforcing spiral ridge and filled into the spiral groove, and its bottom surface is covered. It is characterized by being integrally fused to the outer peripheral surface of the inner tube made of olefin resin. Method for producing a synthetic resin double tube according to claim 5 that.   Reinforced spiral ridges made of semi-molten hard polyvinyl chloride resin have concave and convex locking surfaces on both end surfaces and a flat top surface, while being wound around the outer peripheral surface of the inner tube first. The string-like soft resin filler made of a semi-molten olefin resin to be supplied and filled in the spiral groove between the reinforced spiral ridge portion and the reinforced spiral ridge portion wound next, After filling and filling the spiral groove, the top portion protruding from the spiral groove is flush with the top surface of the reinforcing spiral ridge by a leveling roller that rotates in contact with the flat top surface of the reinforcing spiral ridge. In the spiral groove, it is plastically deformed in contact with the opposing concave and convex engaging surfaces of the adjacent reinforcing spiral ridges and is filled in the spiral groove, and its bottom surface is made of olefin The fusion pipe is integrally fused to the outer peripheral surface of the inner pipe made of resin. Method for producing a synthetic resin double tube according to.

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