JP4217810B2 - Flexible double-layer tube - Google Patents

Description

  The present invention relates to a flexible two-layer pipe in which two pipe layers parallel to each other are formed by partitioning the inside of the pipe with a partition plate, and relates to one mainly used as a supply / exhaust pipe for a ventilator.

  Among such air supply and exhaust pipes, a two-layer pipe in which the inside of the pipe is partitioned by a partition plate to form a two-layer flow path in the pipe longitudinal direction is known. Conventionally, the two-layered tube that has been used is generally not flexible.

  For example, in Patent Document 1 below, a pipe body is formed of a material having rigidity such as metal or hard plastic, and a soft plastic partition plate having fin-like packings at both ends is inserted into the pipe body. Is described. The fin-like packing seals the connection portion with the inner wall surface of the tube body by being brought into close contact with the inner wall surface of the tube body.

  On the other hand, Patent Document 2 describes a two-layer pipe mainly used as a fuel pipe or an oil supply pipe of an automobile, and it is described that the partition plate is joined to the inner wall surface of the pipe body by brazing. It is made of metal that does not have flexibility.

  Moreover, in the following patent document 3, in what is used for the bending part of piping, it gives flexibility by forming the pipe wall of a pipe main body in an uneven | corrugated wave shape, and this makes a bending angle according to the angle of a bending part. Is arbitrarily adjusted.

Japanese Utility Model Publication No.59-174556 Japanese Utility Model Publication No. 60-58985 Japanese Utility Model Publication No. 61-17585

  In the above, in the case where the tube main body is made of a non-flexible material such as metal or hard plastic like the two-layer tube described in Patent Documents 1 and 2, the bent portion of the pipe is the bent portion. There is a disadvantage that a special bent pipe corresponding to the angle of the pipe must be used separately, the types of pipes are increased, and piping is complicated.

  On the other hand, the double-layer pipe of Patent Document 3 is intended for a bent portion, but it can also be used for a straight portion of a pipe because of its flexibility. It is more versatile. However, since the tube body is a corrugated tube, a gap is formed between both ends of the partition plate and the peak portion of the tube body simply by attaching the partition plate in the tube.

  For this reason, it is necessary to fill this gap by some means. Therefore, in the invention of Patent Document 3, a rib having a cross-sectional mountain shape is provided in the longitudinal direction of the tube so that the mountain portion communicates with the mountain portion. And by inserting a partition plate along the concave part inside this rib, the airtightness or liquid tightness of both flow paths is maintained. However, in this configuration, the ribs having a mountain-shaped cross section complicate the tube structure, and the manufacturing cost is high. Further, the corrugated tube main body has a drawback that the smooth flow of the fluid is likely to be hindered due to the unevenness of the inner peripheral surface.

  In addition, in the above conventional example, both end portions of the partition plate and the inner wall surface of the pipe main body are simply brought into close contact with each other or joined by fusion or brazing. However, in the case of a flexible tube, if it is not flexible, if the joint strength at the joint is weak due to its flexibility, the joint is easily peeled off at the time of bending. Or there exists a fault which liquid-tightness will be impaired.

  The present invention eliminates such conventional drawbacks and is excellent in flexibility while having a simple structure, and has high bonding strength between the inner wall surface of the pipe body and the partition plate. An object of the present invention is to provide a flexible double-layer tube excellent in tightness.

  In order to solve the above-mentioned problems, a flexible double-layer tube according to the present invention has a two-layer flow path formed by partitioning the inside of a tube body with a partition plate, and the tube body has a smooth inner wall. A flexible resin-made flexible tube having a wall surface and an outer periphery reinforced with a reinforcing material. Both ends of the partition plate made of a soft resin along the tube longitudinal direction are hot-melted to the inner wall surface of the tube body. It is characterized by being bonded with an adhesive.

And the said hot-melt-adhesive is interposed between the inner wall surfaces of the said pipe | tube main body in the state which went around to the both sides | surfaces continuous from the end surface of the said partition plate. Furthermore, the hot-melt-adhesive front-end | tip part which went around to the both sides | surfaces of the said partition plate is in the state which digged into the both side surfaces of the partition plate. Furthermore, the hot melt adhesive has a melt viscosity of 5000 to 25000 mPa · s.

Further, the reinforcing member is spirally wound around the outer circumference of the pipe body along the longitudinal direction of the pipe, or one or a plurality of reinforcements arranged annularly around the outer circumference of the pipe body with an interval in the longitudinal direction of the pipe It consists of ribs.

Moreover, all of the said pipe | tube main body, a partition plate, a hot-melt-adhesive agent, and a reinforcing material consist of polyolefin resin, and especially the said partition plate consists of foamed resin of a closed cell structure.

  Since the two-layer tube of the present invention forms a two-layer flow path by adhering a partition plate made of a soft resin to a smooth inner wall surface of a flexible tube body with a hot melt adhesive. Although it is simple, it can be easily bent and has excellent flexibility, and it also increases the bonding strength between the inner wall surface of the tube body and the partition plate, making both channels airtight and liquid. It can be excellent in denseness. In addition, since the inner wall surface of the tube main body is smooth, the pressure loss at the time of fluid conveyance can be reduced and the fluid can be smoothly conveyed. Furthermore, since the outer periphery of the tube main body is reinforced with a reinforcing material, it is possible to achieve excellent shape retention with increased flatness against external pressure.

  Further, by causing the hot melt adhesive to wrap around from the end face of the partition plate to both side surfaces, a sufficient bonding area of the hot melt adhesive to the partition plate can be ensured. Furthermore, a hot-melt-adhesive agent can be engaged with a partition plate by making the hot-melt-adhesive front-end | tip part which wraps around the both sides of a partition plate bite into the both sides | surfaces of a partition plate. Thereby, the joint strength between the inner wall surface of the tube body and the partition plate can be further increased, and the air tightness and liquid tightness of both flow paths can be further enhanced.

  Furthermore, by using a hot melt adhesive having a melt viscosity of 5000 to 25000 mPa · s, the hot melt adhesive melts drastically during heating and scatters on the inner wall surface of the tube body, or the hot melt adhesive is insufficiently melted Therefore, it is possible to eliminate a problem that a gap is likely to be generated in the bonded portion, and to secure a good bonded state.

  In addition, by using non-chlorinated polyolefin resin as the material of each constituent member of the two-layer tube, it is possible to obtain an environment-friendly two-layer tube that realizes PVC removal.

  Furthermore, by using a partition plate made of a foamed resin having a closed cell structure, it is possible to easily bite the front end portion of the hot melt adhesive into the partition plate and to reliably engage the partition plate with the hot melt adhesive. In addition, the air-tightness and liquid-tightness can be maintained satisfactorily by reliably blocking between the two flow paths.

  The flexible two-layer pipe according to one embodiment of the present invention is connected to a ventilator installed in a house, for example, and used as a supply / exhaust pipe.

In the figure, (1) is a tube body of a flexible double-layer tube, and this tube body (1) is formed by spirally winding a resin band (2) made of a polyolefin-based elastomer resin. Has been. That is, the pipe body (1) is formed by spirally winding a resin band (2), and the preceding resin band (2) and the resin band (2) following it immediately thereafter. The edge portions along the longitudinal direction are bonded to each other by fusion or adhesive in a state where they are overlapped in the tube diameter direction, thereby forming a circular cross section having a relatively thin wall . Note that the tube body (1) is not limited to the one in which such a resin band is spirally wound, and may be, for example, one formed by extrusion molding or blow molding.

This tube body (1) has a straight tubular shape in which not only the inner peripheral surface but also the outer peripheral surface is smooth. Due to the elasticity of the material called elastomer resin, the tube main body (1) is a flexible tube having a high flexibility. Yes.
A plurality of reinforcing ribs (3) and (4) as reinforcing members are provided on the outer periphery of the pipe body (1), and the pipe body (1) is set to an appropriate flexibility. Sufficient flattening strength is applied to the pressure from the outside.

  (3) is a first reinforcing rib which is one of the two reinforcing ribs (3) and (4), and is a vertical portion (5) and a horizontal connecting to one end of the vertical portion (5). It has a substantially T-shaped cross-sectional shape composed of the portion (6).

The first reinforcing rib (3) is spirally wound in the longitudinal direction of the pipe body (1) while the horizontal portion (6) is in contact with the outer peripheral surface of the pipe body (1). . At this time, a gap wider than the width of the horizontal portion (6) is provided between the preceding side and the following side when the first reinforcing rib (3) is spirally wound. The horizontal part (6) is integrated with the pipe body (1) by fusion or bonding with an adhesive. The first reinforcing rib (3) is made of, for example, a hard polypropylene resin that is a polyolefin-based resin .

  Next, the second reinforcing rib (4) has a very small, substantially triangular cross-sectional shape with respect to the first reinforcing rib (3). The second reinforcing rib (4) is in the middle between the convoluted portions adjacent to the longitudinal direction of the first reinforcing rib (3), with its one surface being in contact with the outer peripheral surface of the pipe body (1). The first reinforcing rib (3) is spirally wound at the same pitch. And this 2nd reinforcement rib (4) is integrated with the pipe main body (1) by melt | fusion or adhesion | attachment by an adhesive agent in a contact part with a pipe main body (1).

The second reinforcing rib (4) is also made of, for example, a hard polypropylene resin which is a polyolefin resin .

  As described above, the pipe body (1) integrally provided with the reinforcing ribs (3) and (4) on the outer periphery is compressed in the longitudinal direction of the pipe when bent, but the second reinforcing rib ( The presence of 4) prevents the compression portion from projecting inwardly and reducing the tube diameter.

  Each of the reinforcing ribs (3) and (4) is spirally wound, but a ring wound in an annular shape may be provided at intervals in the longitudinal direction of the tube. Moreover, the reinforcement rib wound helically may be only one or three or more as a whole.

(7) is a partition plate of the present invention, which is attached so as to cross the inside of the pipe body (1) in the diametrical direction, and the flow path in the pipe body (1) is divided into two layers. The partition plate (7) is made of a foamed resin having a closed cell structure, and specifically, a soft foamed polyethylene resin . The partition plate (7) has a thickness of about 5 mm with respect to a tube diameter of about 100 mm.

As shown in FIG. 1, the partition plate (7) is bonded to the inner wall surface (8) of the tube body (1) at both ends along the tube longitudinal direction. At this time, as shown in FIG. 4, between the end surface (9) in the thickness direction of the partition plate (7) and the inner wall surface (8) of the pipe body, a polyolefin-based hot melt adhesive (15 The partition plate (7) and the pipe body (1) are bonded to each other via the hot melt adhesive (15) .

  Further, the hot melt adhesive (15) is not only interposed between the end surface (9) of the partition plate (7) and the inner wall surface (8) of the pipe body, but also in the central portion which is the portion interposed as such. Bending into an L shape from (16), and the bent side surfaces (17) and (17) wrap around the side surfaces (10) and (10) that are continuous with the end surface (9) of the partition plate (7) Welded with.

  Furthermore, the front end portions of the side surface portions (17) and (17) of the hot melt adhesive (15) are hardened in a state of being wedged into the both side surfaces (10) and (10) of the partition plate (7). By the bite portions (18) and (18) of the hot melt adhesive (15), the partition plate (7) is securely held so as not to be peeled off from the inner wall surface (8) of the pipe body (1). High air tightness and liquid tightness are maintained in the two flow paths (19) and (20) for air and exhaust.

  At the time of the above bonding, the channel-shaped hot melt adhesive comprising the center portion (16) and the side surface portions (17) and (17) as described above is formed at both ends along the pipe longitudinal direction of the partition plate (7). With the cover (15) covered, the partition plate (7) is inserted into the pipe body (1). And as shown in FIG. 4, the predetermined pressure P is applied toward the end surface (9) of a partition plate (7) from the outer side of a pipe | tube main body (1). Then, the central portion (16) of the hot melt adhesive (15) is deformed so as to be crushed along the curved shape of the inner wall surface (8) of the tube body, while being deformed by the inner wall surface (8) of the tube body and the pressure P. It welds to the end surface (9) of the expanded partition plate (7), respectively, thereby ensuring a sufficient adhesion area.

At the same time, the hot melt adhesive (15) extruded from the central portion (16) is moved along the curved shape of the inner wall surface (8) of the tube body, and the side surface portions (17), (17) of the hot melt adhesive (15). ), So that at the front end portions of the side surface portions (17) and (17), a force to bite into the side surface (10) and (10) of the partition plate (7) , that is, the side surface (7) 10) Upon receiving a force F directed toward (10), the tip portion presses the side surfaces (10) and (10) of the partition plate (7). The partition plate (7) made of soft foamed resin is slightly heat-shrinked by the force F and heat force and the side surface (10) (10) is broken, and the side part (17) When the tip portion of (17) enters, it is welded in a state where it has digged in as described above.

As the hot melt adhesive (15), one having a melt viscosity of 5000 to 25000 mPa · s is used. When the melt viscosity of the hot melt adhesive (15) is lower than 5000 mPa · s, the hot melt adhesive (15) is melted in the heat and becomes scattered on the inner wall surface (8) of the tube body. It will stick. As a result, not only the adhesive strength is reduced, but also the scattered part of the hot melt adhesive (15) is hardened to generate protrusions on the inner wall surface (8) of the pipe body, thereby inhibiting the smooth flow of the fluid and ventilating. There is a problem that the connection socket for connecting to a device or the like becomes an obstacle when the end of the double-layer tube is mounted. If the melt viscosity of the hot melt adhesive (15) is higher than 25000 mPa · s, the hot melt adhesive (15) is not sufficiently melted and does not deform along the curved shape of the inner wall surface (8) of the tube body. In addition, there is a problem that a gap is easily generated in the bonded portion, resulting in a decrease in bonding strength. Therefore, a good adhesion state is secured by using a hot melt adhesive (15) having a melt viscosity of 5000 to 25000 mPa · s.

In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of this invention.

1 is a perspective view of a flexible double-layer tube according to an embodiment of the present invention. It is the partially broken side view similarly. It is an expanded sectional view of a reinforcing rib part. It is an expanded sectional view of the adhesion part by a hot-melt-adhesive.

Explanation of symbols

(1) Pipe body
(3) (4) Reinforcement rib (reinforcement material)
(7) Partition plate
(8) Inner wall surface of the pipe body
(9) End face of partition plate
(10) Side of partition plate
(15) Hot melt adhesive
(18) Biting part (hot melt adhesive tip)
(19) (20) Flow path

Claims (6)

A flexible double-layer tube in which a two-layer flow path is formed by partitioning the inside of the tube body with a partition plate, the tube body having a smooth inner wall surface, and the outer periphery thereof being reinforced with a reinforcing material of a resin-made flexible tube, the opposite end portions along the tube longitudinal direction of the partition plate made of soft resin, Yes bonded with a hot melt adhesive to the inner wall surface of the tube body, the hot-melt adhesive Is interposed between the inner wall surface of the tube main body in a state of wrapping around from the end surface of the partition plate to both side surfaces continuous to the end surface . The flexible double-layer tube according to claim 1 , wherein the front end portion of the hot melt adhesive that wraps around both side surfaces of the partition plate bites into both side surfaces of the partition plate . The flexible two-layer tube according to claim 1 or 2 , wherein the hot melt adhesive has a melt viscosity of 5000 to 25000 mPa · s . The reinforcing material is spirally wound around the outer periphery of the tube body along the longitudinal direction of the tube, or from one or a plurality of reinforcing ribs arranged annularly around the outer periphery of the tube body with an interval in the longitudinal direction of the tube The flexible double-layer tube according to any one of claims 1 to 3 . The flexible two-layer tube according to any one of claims 1 to 4, wherein all of the tube main body, the partition plate, the hot melt adhesive, and the reinforcing material are made of a polyolefin resin . The flexible two-layer tube according to any one of claims 1 to 5, wherein the partition plate is made of a foamed resin having a closed cell structure .

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