JP2002254506A - Method and apparatus for continuously manufacturing tube as well as groove forming unit used for the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that since a repulsion force tending to return to an original shape is strongly operated when a thick tube material is rounded in a small diameter, a resistance of passing through a tube forming fixture is first increased so that a treating capability is lowered and the tube is second pulled by the resistance of passing through the fixture so that the tube is elongated, and hence its working accuracy is deteriorated and when the material has a foaming structure, the tube formed by forcibly rounding the material lowers a heat insulation performance due to collapse of the foaming structure of an inner peripheral surface. SOLUTION: A method for continuously manufacturing the tube 10 comprises the steps of bending the tube material of a long-sized state so that both ends 1a of the material 1 in a sheet width direction are butted, heating the butted parts, and heat welding its seam. The method further comprises the steps of forming a plurality of linear grooves Z continued in a longitudinal direction on one side surface of the material 1 for constituting an inner wall of the tube 10, and then bending the tube in a cylindrical state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for continuously producing pipes and a groove forming apparatus used in the method.

[0002]

2. Description of the Related Art A conventional continuous production apparatus and a continuous production method for pipes will be described with reference to FIG. The tube material 1 is made of a thermoplastic resin in the form of a long sheet, and is wound in a roll shape. The continuous pipe manufacturing apparatus A includes a roll 1 of the pipe blank 1.
z, a molded part 20, and a tensile part 30.

[0003] The forming section 20 is roughly constituted by a heating device 21 for injecting hot air and a tube forming jig 22 installed immediately after the heating device 21. The tube forming jig 22 has a basic shape of a cylinder, and the introduction side of the tube material 1 is spread in a funnel shape. In addition, the forming part 20 is provided with an auxiliary forming part 23 composed of a roller or the like having a body part constricted in an arc shape in front of the tube forming jig 22.

[0004] On the other hand, a pulling unit 30 is provided with two feed belts 31 and 31 that endlessly circulate between two pulleys.
It is roughly composed of a pipe feeder 32 disposed on both left and right sides of the cylinder 0 and a cooling device 33 juxtaposed above or below the feed belts 31, 31.

[0005] The tube blank 1 pulled out from the roll 1z passes through the auxiliary forming section 23, the heating device 21, the tube forming jig 22, and the tube feeding device 32.
At 3, the sheet is bent so that both ends in the sheet width direction abut against each other, and the abutting portion is heated to a temperature equal to or higher than a melting point by hot air ejected from the heating device 21. Will be retained. Then, the pipe 10 coming out of the pipe forming jig 22 is pulled by the feed belts 31 of the pipe feeder 32 and sent, and at the same time, the pipe feeder 32.
Is cooled by the cooling device 33 arranged side by side, and the joint is completely joined. In addition, the formed tube 10 is separately wound up by a winding device (not shown), and cut into an appropriate length to obtain a product.

[0006]

The conventional method for continuously producing pipes has the following problems when producing a small-diameter pipe 10 having a large thickness. That is, when the thick tube material 1 is rolled into a small diameter, a repulsive force for returning to the original state is strongly applied, and firstly, the resistance when passing through the tube forming jig 22 is increased and the processing capacity is reduced. Second, the tube forming jig 22
Since the pipe 10 is pulled and extended by the resistance when passing through, the processing accuracy is deteriorated. Further, when the tube material 1 has a foam structure having high heat insulating properties, the tube 10 formed by forcibly rolling the tube material is subjected to compressive stress on the inner peripheral surface and the foam structure collapses. Decrease.

[0007]

As described in claim 1, a tube material in the form of a long sheet is curved so that both ends in the sheet width direction abut, and the abutting portion is heated to heat the joint. In a method for continuously manufacturing a pipe to be welded, a plurality of linear grooves that are continuous in a length direction are formed on one surface (hereinafter, referred to as an inner wall forming surface) of a tube material forming an inner wall of the tube, and then the cylindrical material is formed. Provided is a method for continuously manufacturing a tube which is curved to a predetermined angle.

As described in claim 2, the tube material in the form of a long sheet is curved so that both ends in the sheet width direction abut, and the abutting portion is heated so that the seam is thermally welded. A pipe forming apparatus for forming a plurality of linear grooves continuous in the length direction on the inner wall forming surface of the pipe material before the step of bending the pipe material in the continuous pipe manufacturing apparatus. To provide a continuous manufacturing apparatus.

The method and apparatus for continuously manufacturing a pipe according to the present invention are arranged such that a plurality of linear grooves continuous in the longitudinal direction are formed on the inner wall forming surface of the pipe material so that the pipe can be easily rounded and then bent into a cylindrical shape. Therefore, even if a thick tube material is rolled into a small diameter, there is little repulsion.

[0010] According to a third aspect of the present invention, there is provided a grooved blade having a plurality of blades continuously provided around a rotary drum, and heating means for heating the grooved blade. Provided is a groove forming apparatus that is formed so as to form a plurality of linear grooves that are continuous in the length direction by rotating while being pressed against an inner wall forming surface of a tube material. With this groove forming device, grooves can be easily formed in the tube material.

[0011]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIGS. 1 is a schematic front view of a continuous pipe manufacturing apparatus, FIG. 2 is a vertical front view of a pipe forming jig, FIG. 3 is a vertical side view of a pipe forming jig, and FIG. FIG. 5 is a perspective view of a tube including an enlarged vertical sectional view, FIG. 6 is a perspective view of a tube material including a partially enlarged view, and FIG. 7 is a sectional view of a groove forming apparatus. FIG. 8 is a side view of the groove forming apparatus with a partial cross section.

As shown in FIG. 5, a pipe 10 to be manufactured in Embodiment 1 is obtained by rolling a tube material 1 in the form of a long sheet in the sheet width direction, and connecting a seam 1b formed by joining both ends 1a. It is formed by welding. The tube material 1 is a thermoplastic resin, for example, made of foamed polyethylene. As shown in the enlarged vertical sectional view of FIG. 5, square pyramid (pyramid) projections 1d, 1d. They are arranged like eyes. The thickness of the tube material 1 is about 3 mm for a thin one and 10 mm or more for a thick one.

Thus, the continuous production apparatus S for the pipe 10
Is a roll 1z wound around a tube material 1 in the form of a long sheet as shown in FIG. 1, and a groove forming device 50 which is a main part of the present invention.
0, a forming section 200, and a pulling section 300.

[0014]

[Groove forming apparatus] As shown in FIGS. 7 and 8, the groove forming apparatus 500 includes a machine frame 501 for supporting each member.
And a grooved blade unit 502 suspended vertically on the machine frame 501, and a driven belt 503 below the grooved blade unit 502 and supporting the tube material 1 from below. Is done.

The groove blade unit 502 has its own vertical shafts 504 and 504 inserted through and supported by the machine frame 501 and the air cylinder 5 on the machine frame 501 side.
Bearing frame 506 whose vertical position can be controlled with 05
And a groove blade 508 that is rotatable by supporting its own rotating shaft 507 on the bearing frame 506.
The groove blade 508 is formed by connecting a plurality of mountain-shaped blades at equal intervals around the entire circumference of the hollow rotary drum 509, and can heat the groove to a predetermined temperature using the built-in electric heater 510 as a heating means.
The electric heater 510 is connected to an external power supply via a known rotary connector 511 attached to one end of the rotating shaft 507. In addition, the surface of the groove blade 508 is coated with a resin (for example, a fluorine resin or a silicon resin) having excellent releasability of a synthetic resin for the purpose of preventing adhesion of slag.

[0016]

[Forming Unit] The forming unit 200 is roughly composed of a heating device 210 for injecting hot air and a tube forming jig 220 installed immediately after the heating device 210. In addition, the forming part 2
In addition to 00, an auxiliary molding portion 230 which is located in front of the tube forming jig 220 and is composed of a roller or the like having an arc-shaped neck portion and a tube material 1 for warming and making the tube material 1 flexible. The preheating means (warm air type) 240 is provided.

As shown in FIG. 4, the tube forming jig 220 has a double structure of a jig main body 221 having a basic cylindrical shape and an outer cylinder 222 fitted on the outer periphery of the jig main body 221. A small-diameter body portion 223 is formed on the outer periphery of the jig main body 221 in the longitudinal direction and a gas chamber 224 is formed by surrounding the small-diameter body portion 223 with the outer cylinder 222. A pipe 400 is connected to the outer cylinder 222, and the gas chamber 224 and the gas supply device AP are connected via the pipe 400. Further, the small-diameter trunk portion 2 of the jig main body 221 is provided.
23 are provided with a large number of through-holes 225, 225..., So that gas (for example, air) supplied from the gas supply device AP enters the gas chamber 224, from which the through-holes 225 are formed.
Through the jig body 221 at an appropriate pressure. In FIG. 4, reference numeral 226 denotes a positioning pin projecting from the jig main body 221, and 227 denotes a jig main body 221 and the outer cylinder 22.
A packing member 2 for keeping airtightness, and a reference numeral 250 in FIG. 1 is a guide member for accurately positioning the tube material 1 at a hot air injection position.

[0018]

[Tensioning unit] On the other hand, the pulling unit 300 has two pulleys 3.
Feed belt 31 circulating endlessly between 11 and 311
The system is schematically constituted by a tube feeder 310 in which 2,312 units are arranged on both upper and lower sides of the tube 10.

Next, a description will be given of a method for continuously producing pipes using the above-mentioned apparatus S for continuous production of pipes. First, power is supplied to the electric heater 510 of the groove forming apparatus 500 so that the temperature of the cutting edge is equal to or higher than the melting point of the tube material 1.
For example, when the tube material 1 is foamed polyethylene, its melting point is about 120 ° C., so the temperature of the electric heater 510 is set to 150 ° C. to 190 ° C. In addition, the vertical position of the groove blade unit 502 is adjusted, and the groove blade 508 and the driven belt 5 are adjusted.
The gap 03 is set so as to be smaller than the thickness of the tube material 1.

Next, in this state, the tube material 1 is
3 and the groove blade 508. Then, the groove blades 508 bite into the inner wall forming surface of the tube material 1, and are thermally deformed by heat of the groove blades 508 so that the portions are depressed. When the pipe blank 1 is moved in this state, the groove blade 508 and the driven belt 503 follow or rotate or rotate, so that the pipe blank 1 flows smoothly, and the trace of the passage of the groove blade 508 is continuous as shown in FIG. Linear groove Z
become.

Next, the tube material 1 exits from the groove forming device 500, and has an auxiliary forming portion 230, a heating device 210, a tube forming jig 2
20, continuously pulled by the pipe feeder 310,
On the way, both ends 1 in the sheet width direction are
a, 1a are curved so that they abut each other, and the both ends 1a, 1a are heated to a temperature equal to or higher than the melting point (about 120 ° C.) by hot air (about 300 ° C. to 400 ° C.) blown out from the heating device 210, and the pipe forming jig is heated. The jig main body 221 of the jig 220 keeps the shape of the jig.

The gas chamber 2 of the tube forming jig 220
24 is supplied with gas from the gas supply device AP at all times, and the gas is blown out between the jig main body 221 and the tube material 1. In particular, in the illustrated tube 10, the projections 1d, 1d...
... Because a groove-shaped airway is formed between the air passages, gas is easily released.
In addition, even when there is no protrusion 1d on the outer peripheral surface of the tube 10, if the groove-shaped airway communicating from the through hole 225 to the outside is formed on the inner peripheral surface of the jig main body 221 as described above, Similarly, gas easily escapes.

The jig main body 22 is formed by blowing the gas.
The frictional resistance between the tube material 1 and the tube material 1 is drastically reduced, and the sliding is improved. At the same time, a plurality of linear grooves Z are provided on the inner wall forming surface of the tube material 1 so that the grooves can be easily rounded. Frictional resistance is reduced. Therefore, even when the pipe 10 is pulled by the pipe feeder 310, the pipe 10 hardly expands in the length direction, and since the pipe forming jig 220 has no heat due to the heat radiation effect by the gas flow, the pipe forming jig 220 is During the passage, the temperature of the tube material 1 (tube 10) is reduced, and the thermal welding of the joint 1b is promoted. According to the experiment, the thickness of the tube material 1 was 3
If it is about mm, the temperature is sufficiently lowered at the time of passing through the tube forming jig 220, and the heat welding is almost completed. Therefore,
As shown in FIG.
Just need. Further, when the thickness of the tube material 1 is large, it is necessary to add a cooling device 33 such as a conventional device to the tube feeding device 310.
Due to the heat radiation effect of the gas blown out of the cooling device 33, the length of the cooling device 33 can be reduced to about １ ／ of the conventional length.

[0024]

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 9 is a schematic front view of an apparatus for continuously manufacturing multiple pipes, and FIG. 10 is a perspective view of a pipe forming jig partially cut away.

The pipe to be manufactured in the second embodiment is shown in FIG.
As shown in the figure, the core tube 11 is provided inside the tube 10 of the first embodiment.
Is a multi-tube 100 fitted with. The core tube 11 is a long polyethylene tube. Such a multiple pipe 100 is used, for example, for a water pipe in a house, and the outer pipe 10 serves as a heat insulating cover for a polyethylene pipe as the core pipe 11.

Conventionally, the multi-tube 100 is manufactured by cutting the pipe 10 manufactured by the above-mentioned conventional apparatus into an appropriate length and inserting the core pipe 11 into the pipe 10 later. If the length of the tube 10 is long, there is a problem that the insertion resistance becomes large due to friction and the work becomes difficult.

As shown in FIG. 9, the method and apparatus for continuously manufacturing a multi-tube according to the second embodiment use all of the manufacturing apparatus according to the first embodiment. Therefore, components having the same / same functions as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The multi-tube continuous manufacturing apparatus W is shown in FIG.
As shown in the figure, the jig main body 221 of the tube forming jig 220
The core tube 11 is continuously supplied so as to penetrate straight through the core tube 11. Then, as shown in FIG. 10, the core tube 11 is naturally embraced in the tube material 1 curved by the auxiliary molding portion 230, Since the seam 1b of the tube material 1 is thermally welded as it is, the multiple tube 100 can be continuously formed. If the multi-tube 100 thus produced is used as a core tube and a tube is further covered on the outside in the same manner, a triple tube or a quadruple tube can be easily manufactured.

Although the present invention has been described with reference to the first and second embodiments, the present invention is not limited to the above embodiments. For example, in the embodiment, the built-in electric heater 510 is used as a heating means of the groove blade 508, but a heater may be provided outside the groove blade 508 to heat the groove blade 508 from the outside. In the embodiment, the groove blade 50 is used.
Although the groove Z is formed by thermal deformation by heating the groove 8, the groove Z may be cut into a V shape by a cutter. Further, in the embodiment, a straight line is exemplified as the linear groove Z formed on the inner wall forming surface of the pipe blank 1, but the concept of the continuous linear groove Z includes a broken line and a chain line. The groove Z in such a form can be easily formed by providing a missing portion in a part of the circumference, such as forming the groove blade 508 into a sprocket form.

Further, in the embodiment, the basic form of the tube forming jig 220 is cylindrical, but if it has a function of preventing the seam 1b of the tube material 1 from being opened, a semi-cylindrical form in which the lower half circumference of the cylindrical form is missing. Such a form may be used. Further, the heating device 210 of the embodiment employs a hot air injection method,
You may make it employ | adopt the hot-blade method which heats both ends 1a and 1a of the tube raw material 1 using a hot blade.

[0031]

According to the method and the apparatus for continuously manufacturing a pipe of the present invention, a plurality of linear grooves continuous in the length direction are formed on the inner wall forming surface of the pipe material to make it easy to be rounded and then to be curved into a cylindrical shape. As a result, even if a thick tube material is rolled into a small diameter, the repulsive force is small. Accordingly, the processing ability can be increased because the resistance when passing through the tube forming jig is drastically reduced, and the processing accuracy is good because there is almost no elongation of the tube caused by passing through the tube forming jig. Furthermore, even when the pipe material has a highly heat-insulating foam structure, the compressive stress acting on the inner peripheral surface is small, so the collapse of the foam structure is small, and therefore, the production of tubes utilizing the heat insulation performance of the tube material can be achieved. It is possible.

Further, by using the groove forming apparatus according to the third aspect, there is an effect that a groove can be easily formed in the tube material.

[Brief description of the drawings]

FIG. 1 is a schematic front view of a continuous pipe manufacturing apparatus.

FIG. 2 is a vertical sectional front view of a tube forming jig.

FIG. 3 is a longitudinal sectional side view of a tube forming jig.

FIG. 4 is a perspective view of a tube forming jig shown partially cut away.

FIG. 5 is a perspective view of the tube including an enlarged longitudinal sectional view.

FIG. 6 is a perspective view including a partially enlarged view of a tube material.

FIG. 7 is a sectional view of a groove forming apparatus.

FIG. 8 is a side view of a groove forming apparatus with a partial cross section.

FIG. 9 is a schematic front view of a continuous apparatus for producing multiple tubes.

FIG. 10 is a perspective view of a tube including an enlarged longitudinal sectional view.

FIG. 11 is a schematic front view showing a conventional continuous pipe manufacturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tube material 1a, 1a ... Both ends 1b ... Joint 10 ... Tube 500 ... Groove forming device 508 ... Groove blade 509 ... Rotating drum 510 ... Electric heater (heating means) S, W ... Continuous manufacturing device Z ... Groove

Claims (3)

[Claims] 1. A continuous pipe manufacturing method in which a tube material in the form of a long sheet is curved so that both ends in the sheet width direction abut against each other, and the abutting portion is heated to weld the seam. A plurality of linear grooves that are continuous in the length direction are formed on one surface (hereinafter, referred to as an inner wall forming surface) of a tube material forming an inner wall of the tube, and are then formed into a cylindrical shape. Continuous manufacturing method. 2. A continuous pipe manufacturing apparatus in which a tube material in the form of a long sheet is curved so that both ends in the sheet width direction abut against each other, and the abutting portion is heated to thermally weld a seam. Prior to the step of bending the pipe material, a continuous pipe manufacturing apparatus characterized by providing a groove forming apparatus for forming a plurality of linear grooves continuous in the length direction on the inner wall constituting surface of the pipe material. . 3. A grooved blade comprising a plurality of blades connected in series around a rotary drum, and a heating means for heating the grooved blade, wherein the heated grooved blade is pressed against an inner wall forming surface of a tube material. A groove forming apparatus used in a continuous pipe manufacturing method, wherein a plurality of linear grooves continuous in the longitudinal direction are formed by rotating while rotating.