JPS6034590A - Double wall pipe and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-walled pipe used as a drain pipe, etc., and a method for manufacturing the same.

Double-walled pipes, in which a cylindrical inner wall is heat-sealed to the inner surface of a reinforcing outer wall that has alternating annular peaks and valleys, have excellent earth pressure resistance, so they can be used underground like drainage pipes. It may be used by being buried inside.

Conventionally, this type of 2N hard tube was manufactured by extruding a synthetic resin for wound formation from an extruder onto the uneven molding surface of a pair of opposing half-molding molds at a constant speed, and by extruding the same as described above. After the molten resin outer layer with peaks and troughs is intermediately molded, a synthetic resin for forming the inner wall is extruded from an extruder into a cylindrical shape onto the inner surface of the troughs of the outer layer. The inner layer of molten resin is formed by heat-sealing the inner surface of the trough, and the molded product thus obtained is formed into an m-shape after curing, and then cut into pieces of predetermined size.

Therefore, when connecting double-walled pipes on-site, each connecting throat of the two double-walled pipes is inserted into a separately prepared connecting joint. However, according to this, a connection joint is required separately, and the work of connecting the 2mfM pipe is troublesome.
Furthermore, there was also a disadvantage in appearance that the connecting joint protruded from the outer periphery of the connecting portion.

The present invention was made to improve the conventional drawbacks,
The purpose of this is to eliminate the need for connection joints that were previously required, to make the connection work easier and faster, and to create a double wall with a good appearance, with the connecting part and other parts having approximately the same shape. The objective is to propose an effective manufacturing method.

That is, the double rigid tube according to the present invention can be
In addition, the manufacturing method of the 2jlA a % according to the present invention includes providing a socket molding surface and a socket molding surface of a predetermined shape as part of the above-mentioned conventional molding. Then, under predetermined pressure conditions, a molten resin layer for forming an outer wall and a molten resin layer for forming an inner wall are sequentially injected onto the molded surfaces, and the part corresponding to the insertion port and the receiving part in the obtained molded product are It is cut and separated at a predetermined position so that the mouth portion is held at both ends.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The double-walled pipe and method for manufacturing the same according to the present invention will be explained below with reference to the drawings.

FIG. 1 shows a double-walled tube (1) according to the invention. That is, a double-walled pipe (t+ is a two-part synthetic resin inner wall (2) and a synthetic resin outer wall (3) surrounding the outer tube).
It has a socket at one end (41, a socket at the other part) 5
). The outer wall (3) has the above-mentioned socket (4).
), the annular peaks (8a) and valleys (
8b) alternately, and these peaks (8a) and valleys (8b) improve pressure resistance. In addition, the inner wall (2) is heat-sealed to the inner surface of the trough (8b) of the outer wall (4) and the inner surface of the outer wall (3) at the socket (41). ) is configured to have the same or almost the same inner diameter as the outer diameter of the socket (4).

When connecting such a double-walled pipe (11),
Two double-walled tubes connected to each other, like at fil
After matching the socket (5) of the il+ with the socket (4), insert the socket (4) into the socket (5) as shown in the same figure (bl). An adhesive or a sealant is applied between the socket and the socket (5) as necessary to ensure watertightness between the two.

In addition, as is clear from Fig. 2fbl, by setting the length of the socket (4) and the length of the socket (5) to predetermined values, the peak pitch P1 of the connection part and the other Since the peak pitch P2 of the portion is the same, the shapes of the connecting portion and other portions are uniform, which is preferable in terms of appearance.

FIG. 3 la) shows a variant. That is, the socket (4)
Since the convex strip (6) is deformed at one or more locations (two locations in the illustrated example) against its elasticity,
The bond-like excitation between the two becomes -n strong.

In addition, the above-mentioned protrusion (6) is inserted into the socket (5) as shown in the illustrated example.
If the troughs (8b) are formed corresponding to the mutual positions in the figure (bl), the peaks f914+(leaf root l, - its C-shaped part) of the socket plate 1 in the connected state can be formed as shown in the same figure (bl). It has a structure that engages in the winter (6) force (extraction direction), which has the advantage of providing a stronger joint.

A preferred method for manufacturing the double-walled tube described above will be explained together with the manufacturing apparatus shown in FIG. 4.

In FIG. 4, αD is a molten resin extrusion part, and this molten resin extrusion part I is a first molten resin which opens in an annular shape at the outer circumference of the rear end of a concave part υ of a constant width formed at the outer part of the molten resin extrusion part I. A passage (18a) and a second molten resin passage Wt (1B+) opening in an annular shape at the outer circumference of the tip of the extrusion part OB,
It has a first air supply path (14a) communicating with the recessed part @ and a second air supply 1i'114b) that opens inside the annular opening in the second molten resin passage (18b), Intake f that opens immediately behind the resin passage (18b)
It has iB(14c). Cooling water is then passed through the cooling water system 00, which has a double pipe structure, passing through a water-cooling type cooling f5 (one is arranged, and this cooling cylinder α9 is connected to the above-mentioned extrusion part 0]) concentrically in the front part of this extrusion part Qil. is configured to be supplied and discharged.

Next, αη is a mold. This mold Q7) includes a tube body molding surface A, a receiving and receiving command molding surface, and a pusher molding surface C, and the socket molding surface B and the insertion molding surface C are different from the tube body molding surface A.
It is formed so as to be continuous in the middle in the longitudinal direction. The tube body molding surface A has an annular concave portion A1 and a convex portion A.
2 alternately.

In addition, the socket molding surface B also has annular recesses nB B 1 and convex portions B2 alternately, similar to the tube body molding surface A, but the convex portions? JB2 has a larger diameter than the convex portion A2 on the molding surface A of the tube body. Note that the concave portion B1 is located at the four portions Al of the tube body molding surface A.
It has the same diameter. Further, the insertion port molding surface C is a cylindrical surface having the same diameter as the convex portion A2 on the tube body molding surface. In the illustrated example, the mold aη is divided into a pair of half molds, and each half mold is made up of endlessly continuous multi-shell molding blocks (17a), which are connected to the molten resin extrusion section Ql. ) and around the cooling cylinder f5+ in the direction indicated by the arrow in FIG. 4 in synchronization at a fixed position.

In such a manufacturing device, the α force of the mold is controlled as indicated by the arrow × in Fig. 4.
While running at a predetermined speed in the direction, the molten plum fat extrusion section Q
The molten resin is continuously pushed out through the first molten resin passage (18a) and the second molten resin passage (18b) of ll, and at the same time, air is supplied into the recessed part (2) through the first air supply passage (14a). Exhaust air from the intake path (14c).

Further, when the socket molding surface B passes through the second air supply path (14b), a predetermined timing is taken, and the second air supply [+B (14
Air is supplied from b).

In this way, the molten resin extruded into a cylindrical shape from the first molten resin passage E6 (18a) is sucked into the concave portion □, and due to the differential pressure between the inside and outside, the tube body molding surface A, The molten resin outer layer P1 is formed by being pressed against the receiving molding surface B and the insertion molding surface C, and each molding surface A%B is
It is molded into a shape that follows %C. On the other hand, the second molten resin passage I
The molten resin extruded from i & (18b) is
Due to the crotch effect caused by exhausting air from t(14c), it immediately adheres to the inner surface of the molded molten resin outer layer PI and is thermally fused to form a molten resin interior KtP2. In this case, when extruding the molten resin inner layer P2 against the molten resin outer layer PI formed by the tube body molding surface A, the suction force through the intake passage (14c) is applied to the core if P 2 of the above-mentioned outer MP1. It is necessary to set it to such an extent that it does not bulge into the internal space Sl of the peak.

By the way, the air supplied from the second air supply path (14b) passes through the molten resin outer layer 1 formed by the socket molding surface B around the opening of the second molten resin path (18b). Do this only during certain hours. This is because the upper limit of the suction force by the intake path (14c) is regulated for the above-mentioned reason.
By increasing the pressure difference between the inside and outside of the molten resin inner layer P2, it is necessary to ensure that the inner layer P2 adheres to the inner surface of the large diameter valley of the molten resin outside aPx in this part and to thermally melt it. by. Even in this case, the differential pressure needs to be set to a value that does not cause the molten resin inner layer P2 to bulge out into the internal gap S2 at the peak of the molten resin outer layer P1.

Inner and outer molten resin layers P1 thermally fused as described above,
Thereafter, P2 is sequentially sent to the cooling cylinder αυ side as the mold αη moves, and is cooled and hardened.

After curing, it is molded into a single mold.

The molded article P thus obtained is shown in FIG. As shown in the figure, this molded product P has a portion corresponding to the tube body (601)
Since it is provided with an inlet equivalent part (401) and a socket equivalent part (501) that are continuous with each other at equal pitches at multiple locations along the way, the inlet equivalent part (401) and the socket equivalent part (501) are provided. )
Cut the boundary part along the cutting line E and the row opening and separate. Furthermore, in the case of Fig. 6, two continuous socket-equivalent parts (401) and two successive socket-equivalent parts (501) are formed and separated by cutting along the cutting lines E and Rollo at the center of each. .

In this way, the double-walled tube (1) described in FIG. 1 can be efficiently obtained.

As detailed above, according to the double-walled pipe of the present invention, double-walled pipes can be easily and quickly connected without using a conventionally necessary connecting joint, and the connecting part and other parts can be connected easily and quickly. Since it is difficult to distinguish between the two, it is also superior to conventional products in terms of appearance. Further, according to the manufacturing method of the present invention, it is possible to simultaneously manufacture a plurality of double-walled tubes, so that rationalization and cost reduction of the double-walled tube manufacturing line can be easily achieved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a double-walled pipe according to the present invention, FIG. An explanatory diagram of the pipe connection procedure, Fig. fiJ4 is a sectional view showing the manufacturing equipment for double walls, etc.
The figure is an enlarged sectional view of a main part of a molded product, and FIG. 6 is an enlarged sectional view of a main part of another molded product. (1)...Double wall pipe, (2)...Inner wall, (3)...
・Outer wall, (8a)...crest, (3b)...trough,
(4)...Socket, (401)...Socket equivalent part, (
5)...Socket, (501)...Socket equivalent part, αη・
...Mold, A...Pipe body molding surface, A1...Concavity on tube body molding surface, A2...Protrusion on tube body molding surface, B...Socket molding surface, B1... Recessed part of socket molding surface, B
2... Convex portion of socket molding surface, C... Stitch molding surface, P... Molded product, Pl... Molten resin outer layer, B2... Molten resin inner layer. Patent applicant Takiron Co., Ltd.

Claims (2)

[Claims] (1) In a double-walled tube in which a cylindrical inner wall is heat-sealed to the inner surface of an outer wall having alternating annular peaks and troughs, one end has an insertion hole and the other end has a receptacle into which the opening is inserted. What is claimed is: 1. A double rigid pipe comprising a mouth, and wherein peaks and troughs of the outer wall extend along the entire length of the outer wall excluding the embossed seams. (2) A tube body molding surface that alternately has annular concave portions and convex portions, a socket molding surface that alternately has concave portions and convex portions larger in diameter than the aforementioned convex portions, and a socket molding surface that has the same diameter as the convex portions on the tube body molding surface. The molten resin is extruded into a mold equipped with a molding surface and a molten resin outer layer is formed along the eight molding surfaces.While shaping the molten resin, the molten resin is extruded into the outer layer into a cylindrical shape, and the inner and outer surfaces are A pressure difference is generated between the molten resin and the molten resin is adhered to the inner surface of the valley part and the inner surface of the part corresponding to the insertion hole of the outer layer and thermally fused, thereby forming a cylindrical molten resin.
A method for producing a double-walled pipe, which comprises forming a resin inner layer and then cutting and separating the obtained molded product at a predetermined position so that both parts have a part corresponding to a pusher and a part corresponding to a socket.