KR101414809B1 - Appartus for manufacturing pipe which removes residual stress, the method using thereof, and pipe manufactured by the method - Google Patents

Abstract

The present invention relates to a pipe manufacturing apparatus capable of removing residual stress, a manufacturing method using the same, and a pipe manufactured thereby, and more specifically, to a pipe manufacturing apparatus capable of removing residual stress, a manufacturing method using the same, and a pipe manufactured thereby, wherein the apparatus injects raw materials melted within dies having difference channels by two extruders; maintains the temperature of the raw materials passing the channels of the pipe within the dies at a lower level to maintain the internal temperature of the pipe discharged from the dies at a lower level; and continuously injects cooling air into the pipe via cooling air discharge pipe discharged and extended from the inside of the dies.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pipe manufacturing apparatus capable of removing residual stress, a manufacturing method using the same and a pipe manufactured by the manufacturing method. [0002]

The present invention relates to a pipe manufacturing apparatus capable of removing residual stress, a manufacturing method using the pipe manufacturing method, and a pipe manufactured by the manufacturing method. More specifically, the present invention relates to a pipe produced by injecting molten raw materials into dies having different channels with two extruders The temperature of the raw material passing through the channel forming the inside of the pipe in the die is kept to be lower so that the internal temperature of the pipe discharged from the die is kept lower and the pipe The present invention relates to a pipe manufacturing apparatus capable of eliminating residual stresses that remove residual stress by injecting cooling air into a pipe, a manufacturing method using the same, and a pipe manufactured by the manufacturing method.

Generally, the pipe manufacturing apparatus is made by heating synthetic resin to a predetermined temperature and melting it, and then passing the die through injection or extrusion to produce a desired shaped product.

1, the conventional pipe manufacturing apparatus 10 includes an extrusion device 11 for extruding a synthetic resin, a cutting device 12 for cutting a synthetic resin having passed through a cooling device 12 for cooling a molded product formed by extruding a synthetic resin, Device 14 is included.

Here, the cooling device 12 is configured to maintain the shape of the molded article discharged from the extrusion device 11 by rapidly cooling the molded article by injecting the low-temperature cooling water to the nozzle 13 with respect to the molded article discharged at a high temperature in the extrusion device 11 .

However, when cooling water is sprayed on the outer surface of the molded product in the cooling device 12, the surface is rapidly cooled, while residual stress is generated in the interior thereof, and the shrinkage ratio of the surface layer and the inner layer largely varies. Also, at the time of production, molded articles that were correctly manufactured were also damaged or cracked when they were continuously exposed to a low temperature environment.

To solve these problems, Japanese Patent Application Laid-Open No. 10-166468 (method and apparatus for manufacturing a thermoplastic resin pipe) was filed and disclosed.

2, the apparatus for manufacturing a thermoplastic resin tube comprises an extruder 1, a die 2 for pushing a polyolefin resin melt-knitted by the extruder 1 into a cylindrical shape, a die 2 A low pressure water tank 3 and a cooling water pond 4 for cooling the pipe discharged from the cooling water pond 4, a heating device 7 for annealing the cooled pipe, A taking-over device 5 for taking over, a cooling device 8 for cooling the pipe before cutting it, and a cutting device 9 for cutting the pipe.

However, in the conventional apparatus for manufacturing a thermoplastic resin tube, when the raw material is injected into the die through one pipe, and the die is discharged in the form of a pipe while maintaining the die at a predetermined temperature, there is no temperature difference between the inside and the outside of the pipe. The outer surface of the pipe is cooled by the cooling water in the discharged vacuum water tank. The inner surface of the pipe is cooled by the cooling water discharged from the cooling pipe extended to the decompression water tank by being discharged from the inside of the pipe, The inner temperature of the pipe rises due to the heat released from the inner pipe and the latent heat of the inner pipe, and the inner temperature continues to be maintained even after reheating the outer surface, so that the residual stress remains.

Further, since the apparatus for annealing such a conventional pipe is composed of a far-infrared ray heater, there is another problem that it is difficult to maintain the pipe at a predetermined temperature by melting the pipe due to the heat at high temperature irradiated by the heater.

Japanese Patent Laid-Open No. 10-166468

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a melt extrusion molding method of injecting molten raw materials into dies having different channels with two extruders, A pipe capable of eliminating residual stress that allows residual stress to be maintained by keeping the internal temperature of the pipe discharged from the die at a lower level and continuously injecting cooling air into the pipe through an extended cooling air discharge pipe discharged from the inside of the die, A manufacturing method using the same, and a pipe manufactured by the manufacturing method.

In addition, the present invention is characterized in that the heated water heated to a predetermined temperature during annealing is sprayed onto the surface of the pipe and reheated to a predetermined temperature to significantly reduce the temperature deviation of the surface layer and the inner layer of the pipe to eliminate residual stress, (Hereinafter referred to as "jar phenomenon") in which the both end portions of the pipe are curled in the direction of the inner surface of the pipe at both ends, and the residual stress is removed Another object of the present invention is to provide a pipe manufactured by the manufacturing method and a manufacturing method thereof.

Further, the present invention relates to a pipe manufacturing apparatus capable of modifying the surface of a pipe by treating the surface of the pipe with a corona discharger to remove residual stress to improve hydrophilicity, improve adhesion, and remove rolling oil, There is another object to provide a pipe manufactured by the method.

According to an aspect of the present invention,

First and second extruders for melting and discharging the charged synthetic resin material; A die for supplying the molten resin discharged from the first and second extruders to the outer channel and the inner channel and discharging the pipe from the discharge channel and maintaining the temperature of the inner channel lower than the temperature of the outer channel, ; A vacuum cooling tank through which the pipe discharged from the die passes and which keeps the outside of the pipe in a vacuum state and injects cooling water onto the surface of the pipe to cool the pipe; An annealing tank through which the pipe cooled and discharged in the vacuum tank passes, and injects heated water onto the surface of the pipe; A cooling tank through which the pipe heated and discharged in the annealing tank passes, and injects cooling water into the pipe to re-cool the pipe; A drawer installed at a rear end of the cooling bath to continuously move the pipe discharged from the die; A corona discharge unit for discharging corona discharges from the corona discharge unit; a corona discharge unit for discharging corona discharges from the corona discharge unit; A cutter for cutting the pipe passing through the corona discharge machine to a predetermined length; And a plurality of air holes formed outside the corona discharge unit, the plurality of air holes being formed in the corona discharge unit, the cooling air flowing through the dies, And a control unit.

Here, the pipe manufacturing apparatus capable of removing the residual stress further includes a cooling air supplier for supplying cooling air to the cooling air discharge pipe.

Here, the pipe manufacturing apparatus capable of removing the residual stress further includes a heating water supply unit for supplying heating water at 80 to 100 ° C to the annealing tank, reheating the heated water discharged from the annealing tank, and supplying the heated water.

Here, the pipe manufacturing apparatus capable of removing the residual stress further includes a printing machine for printing a necessary record on the surface of the pipe installed between the cooling bath and the corona discharger.

Here, the die may further include a first heater installed on an outer surface of the die to heat the molten resin of the outer channel; A second heater installed in the inner channel to heat the molten resin of the inner channel; A guide hole for a cooling air discharge pipe through which the cooling air discharge pipe passes; And an oil cooling coil for preventing the internal temperature from rising above the reference temperature.

Here, the oil cooling coil receives the oil cooled from the oil cooler provided outside, cools the inside, and discharges the heated oil to the oil cooler.

Here, the first heater maintains a temperature of 190 to 220 ° C, and the second heater maintains a temperature of 170 to 180 ° C.

In this case, the vacuum cooling bath is provided with a plurality of first cooling pipes in a radial direction with respect to a center point in the longitudinal direction, and the surface of the pipe through the first nozzle arranged in each of the first cooling pipes is 10 to 30 Lt; 0 > C.

Here, it is preferable that the annealing tank has a plurality of heating pipes in a radial direction with respect to a center point in the longitudinal direction, and the heating is performed by supplying heat from the heating water supply unit to the surface of the pipe through the second nozzle arranged in each heating pipe Spray water.

Here, it is preferable that the cooling bath has a plurality of second cooling pipes in a radial direction with respect to a center point in the longitudinal direction, and the surface of the pipe is connected to the cooling pipe through a third nozzle arranged in each of the second cooling pipes, Of cooling water.

Here, the cooling air discharge pipe is provided with a heat insulating material on its surface.

Here, when the pipe is discharged from the die, the outer surface temperature is maintained at 190 to 220 캜, and the inner temperature is maintained at 170 to 180 캜.

According to another aspect of the present invention,

The method of manufacturing a pipe using a pipe manufacturing apparatus capable of removing residual stress as described above is characterized in that the molten resin of the first extruder is supplied to the outer channel of the die and the molten resin of the molten resin of the second extruder is supplied to the inner channel of the die A supply step; A pipe discharging step of supplying the outer channel and the inner channel of the die and discharging the pipes by mixing them in the discharge channel and keeping the temperature of the inner channel lower than the temperature of the outer channel; A vacuum cooling step of injecting a pipe discharged from a die into a vacuum cooling tank to inject cooling water on a surface in a vacuum state to cool the cooling pipe, and cooling the inside of the pipe with cooling air discharged through a cooling air discharge pipe; An annealing step of injecting the pipe discharged from the vacuum cooling tank into the annealing tank to spray heated water on a surface thereof to cool the inside of the pipe with cooling air discharged through the cooling air discharge pipe; A cooling step of cooling the inside of the pipe with cooling air discharged through the cooling air discharge pipe by injecting the pipe discharged from the annealing tank into a cooling bath to spray cooling water on the surface thereof; A corona discharging step of pulling the pipe discharged from the cooling bath with a drawer and performing a corona discharge through a corona discharger on the surface of the pipe discharged from the drawing machine to process the surface; And a cutting step of cutting the pipe passing through the corona discharge machine to a predetermined length by a cutter.

Here, the pipe manufacturing method capable of removing the residual stress further includes a printing step of printing a necessary record through a printing machine on the surface of the pipe discharged from the cooling bath and introduced into the drawing machine.

Here, the printing process cools the inside of the pipe with cooling air discharged through the cooling air discharge pipe at the same time as printing.

Here, in the pipe discharging step, the outer channel of the die is maintained at a temperature of 190 to 220 캜, and the inner channel is maintained at a temperature of 170 to 180 캜.

Here, in the annealing step, heating water of 80 to 100 占 폚 is supplied to the annealing tank from a heating water feeder, and the heated water discharged from the annealing tank is reheated.

Here, in the vacuum cooling step, cooling water of 10 to 30 DEG C is sprayed on the surface of the pipe.

Here, in the cooling step, cooling water of 10 to 30 DEG C is sprayed on the surface of the pipe.

According to still another aspect of the present invention,

And a pipe manufactured by a pipe manufacturing method capable of removing the residual stress.

According to the pipe manufacturing apparatus capable of removing the residual stress of the present invention as described above, the manufacturing method using the same, and the pipe manufactured by the manufacturing method, the molten raw material is injected into the die having the different channels with the two extruders The temperature of the raw material passing through the channel forming the inside of the pipe in the die is kept to be lower so that the internal temperature of the pipe discharged from the die is kept lower and the pipe The residual stress can be removed by reducing the temperature deviation of the surface layer and the inner layer of the pipe by injecting the cooling air into the inside.

According to the present invention, heating water heated to a predetermined temperature during annealing is sprayed onto the surface of a pipe and reheated to a predetermined temperature to significantly reduce temperature fluctuations in the surface and inner layers of the pipe, thereby removing residual stress, (Hereinafter referred to as "jar phenomenon") in which the both ends of the longitudinal incision side of the pipe are curled and overlapped with each other, and the bending of the both ends in the pipe inner surface direction can be eliminated.

Further, according to the present invention, the surface of a product is treated with a corona discharge machine to modify the surface of the pipe to improve hydrophilicity, improve adhesion and remove rolling oil.

1 is a schematic diagram schematically showing a conventional pipe manufacturing apparatus.
2 is a block diagram showing a conventional apparatus for manufacturing a thermoplastic resin tube.
3 is a block diagram showing the configuration of a pipe manufacturing apparatus capable of removing residual stress according to the present invention.
4 is a diagram showing the temperature of each step of a pipe manufacturing apparatus capable of removing residual stress according to the present invention.
5 is a front sectional view schematically showing the structure of a vacuum cooling bath, an annealing bath and a cooling bath among pipe manufacturing apparatuses capable of removing residual stress according to the present invention.
6 is a cross-sectional view showing the structure of a die in a pipe manufacturing apparatus capable of removing residual stress according to the present invention.
7 is a process diagram for explaining a pipe manufacturing method capable of removing residual stress according to the present invention.
FIG. 8 is a perspective view showing a pipe in a heat-treated state and a non-heat-treated pipe according to a manufacturing method of FIG. 7 for comparison.
FIG. 9 is a view schematically showing the roughness of the pipe surface in the heat-treated state and the non-heat-treated state according to the manufacturing method of FIG.
FIG. 10 is a cross-sectional view of pipes in a heat-treated state and in a non-heat-treated state according to the manufacturing method of FIG.

Hereinafter, the structure of a pipe manufacturing apparatus capable of removing residual stress according to the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

FIG. 3 is a schematic view showing the construction of a pipe manufacturing apparatus capable of removing residual stress according to the present invention, FIG. 4 is a diagram showing the temperature of each step of a pipe manufacturing apparatus capable of removing residual stress according to the present invention, FIG. 6 is a cross-sectional view schematically showing the construction of a vacuum cooling bath, an annealing bath and a cooling bath in a pipe manufacturing apparatus capable of removing residual stress according to the present invention. Sectional view showing the structure of the dice.

3 to 6, a pipe manufacturing apparatus capable of removing residual stress according to the present invention includes a first extruder 110, a second extruder 120, a die 130, a vacuum cooling tank 140, The cooling air supply unit 220 and the heating water supply unit 220 are connected to each other by the heating unit 200. The annealing unit 150 is connected to the cooling unit 160, And a feeder (230).

First, the first extruder 110 is a device for dissolving a pellet of a synthetic resin into a molten resin at a high temperature and supplying the molten resin to the outer channel 131 of the dies 130 do.

The second extruder 120 is a device for melting a high-temperature pellet of a synthetic resin and converting the pellet into a molten resin. The molten resin is supplied to the inner channel 132 of the dies 130 do. At this time, the second extruder 120 may be loaded with pallets of the same material or different materials of different colors.

The dies 130 are provided to mold the molten resin discharged from the first extruder 110 and the second extruder 120 so that the molten resin is discharged to discharge the pipe P. The first extruder 110 The discharged molten resin is supplied to the outer channel 131. The melted resin discharged from the second extruder 120 is supplied to the inner channel 132 and mixed in the discharge channel 133, . Here, the die 130 includes a first heater 134 installed on the outer surface to heat the molten resin of the outer channel 131, a second heater 134 installed inside to heat the molten resin of the inner channel 132, A guide hole 136 for the cooling air discharge pipe through which the cooling air discharge pipe 210 to be described later passes and an oil cooling coil 137 for preventing the internal temperature of the die 130 from rising above a reference temperature, ). It is preferable that the first heater 134 maintains a temperature of 190 to 220 ° C. and the second heater 135 maintains a temperature of 170 to 180 ° C. The oil cooling coil 137 is an oil The oil cooled by the cooler 138 is supplied to cool the inside of the die 130, and the heated oil is discharged to the oil cooler 138.

In order to prevent the deformation of the pipe P discharged from the die 130 due to gravity and its own weight due to gravity and its own weight, the vacuum cooling bath 140 maintains the surface of the pipe P in a vacuum state Cooling water is sprayed on the surface of the pipe P in order to rapidly cool the pipe P in a state of being deformed under vacuum and to maintain the original shape discharged from the die 130. Here, the vacuum cooling bath 140 is provided with a plurality of first cooling tubes 141 radially with respect to the center point C in the longitudinal direction, and a center point C is formed in each of the first cooling tubes 141 Cooling water of 10 to 30 DEG C is sprayed to the entire surface of the pipe P through the first nozzle 143 arranged so as to face the pipe P so that the temperature is rapidly conducted to the entire pipe P to be cooled. At this time, cooling air is injected into the pipe P through the cooling air discharge pipe 210 to lower the internal temperature.

Annealing is a method of annealing annealing to prevent residual stress from occurring by minimizing the variation of the temperature of the inner layer and the surface layer of the pipe P by reheating the cooled pipe P, And the heated water is sprayed onto the surface of the substrate P. Here, the annealing tank 150 is provided with a plurality of heating tubes 151 in a radial direction with respect to a center point C in the longitudinal direction, and a plurality of heating tubes 151 arranged in the respective heating tubes 151 2 nozzle 153 to spray the whole surface of the pipe P with heating water of 80 to 100 ° C so that the temperature of the entire pipe P is rapidly conducted and heated. Here, the annealing bath 150 is installed at a distance of about 3 m from the vacuum cooling bath 140, and a curtain-shaped transparent sealing film 155 is formed therebetween, so that the outside cold cooperate with the hot steam inside So that the temperature inside the annealing tank 150 is prevented from being lowered, and the pipe P is preheated by the internal steam. At this time, cooling air is injected into the pipe P through the cooling air discharge pipe 210 to lower the internal temperature.

Subsequently, the cooling bath 160 injects cooling water onto the surface of the pipe P. Here, the cooling bath 160 is provided with a plurality of second cooling pipes 161 in a radial direction with respect to the center point C in the longitudinal direction, and a center point C is formed in each of the second cooling pipes 161 Cooling water of 10 to 30 DEG C is sprayed to the entire surface of the pipe P through the third nozzle 163 arranged so as to cool the entire pipe P to be cooled quickly. At this time, cooling air is injected into the pipe P through the cooling air discharge pipe 210 to lower the internal temperature.

Then, the printer 170 is installed to print the product of the product and the producer on the surface of the pipe P discharged from the cooling bath 160.

Then, the drawing machine 180 is installed to transport the pipe P until it is cut by the cutter 200, which will be described later, after being discharged from the dies 130.

The corona discharger 190 reforms the surface of the pipe P discharged from the drawer 180 to corona discharge on the surface of the pipe P in order to improve the hydrophilicity, An electrode 193 fixed to the wire 191 connected to the die 130 is positioned inside the pipe P when the pipe P discharged from the inserter 180 is passed.

Further, the cutter 200 is installed to cut the finished pipe P to a predetermined length or a set length interval. For example, according to the present invention, the internal temperature of the pipe P entering the cutter 200 is approximately 25 占 폚, and the surface temperature is approximately 25 占 폚, and the internal and external temperatures of the pipe P are approximately the same. Thereafter, the internal temperature of the pipe P cut by the cutter 200 is approximately 20 占 폚, and the surface temperature is approximately 20 占 폚.

Subsequently, the cooling air discharge pipe 210 is directly connected to the cooling air discharge pipe 210 by the cooling water or the heating water while the pipe P passes through the vacuum cooling bath 140, the annealing bath 150, the cooling bath 160 and the printing machine 170 By blowing air at 20 to 30 ° C to a region that is not cooled or heated, the heat is cooled so that the heat conduction between the directly cooled portion and the other portion is smoothly performed. Here, the cooling air discharge pipe 210 passes through the guide hole 136 for the cooling air discharge pipe of the dice 130, is fixed along the wire 191 of the corona discharge device 190, and is discharged from the dies 130 to the corona discharge device 190 to the electrode 193 and a plurality of air holes 211 are provided on the outside so that the cooling air introduced from the outside is sprayed into the pipe P and the heat insulating material 213 is provided on the surface desirable.

Subsequently, the cooling air supplier 220 supplies cooling air to the cooling air exhaust pipe 210. At this time, the cooling air supplier 220 has a pump (not shown) to discharge air into the internal space of the pipe P, and the cooling air to be discharged is 20 to 30 ° C.

On the other hand, the heating water supplier 230 supplies heating water of 80 to 100 ° C to the annealing tank 150, and reheats and supplies the heating water discharged from the annealing tank 150. At this time, it is natural that the cooling air supplier 230 includes a heater (not shown) and a temperature sensor (not shown) so as to heat the heated water to a predetermined temperature, and the temperature of the heated water is preferably 90 ° C.

Hereinafter, a method of manufacturing a pipe capable of removing residual stress according to the present invention will be described in detail with reference to the accompanying drawings.

7 is a process diagram for explaining a pipe manufacturing method capable of removing residual stress according to the present invention.

&Quot; Molten resin supply process-S100 "

The molten resin of the first extruder 110 is supplied to the outer channel 131 of the dies 130 and the molten resin discharged from the second extruder 120 is supplied to the inner channel 132 of the dies 130 Supply.

&Quot; Pipe discharge process-S 110 "

The molten resin supplied to the outer channel 131 and the inner channel 132 of the die 130 is mixed and shaped in the discharge channel 133 and discharged to the pipe P. [ At this time, the die 130 controls the external channel 131 to the temperature of 190 to 220 ° C by controlling the first heater 134, controls the internal channel 132 to the second heater 135, ° C and blocks the die 130 from being heated above the reference temperature by accumulated heat through the oil cooling coil 137. In addition, the pipe P discharged directly from the die 130 maintains the outer surface temperature at about 190 캜 and the inner temperature at about 180 캜.

&Quot; Vacuum cooling process-S120 "

The pipe P discharged from the dies 130 is supplied to the vacuum cooling tank 140 to cool the surface of the pipe in a vacuum state to cool the pipe P. The cooling air discharged through the cooling air discharge pipe 210 flows through the pipe P). At this time, the temperature of the cooling water is 10 to 30 캜, and the temperature of the cooling air is 20 to 30 캜. Further, the pipe P discharged directly from the vacuum cooling bath 140 has an outer surface temperature of about 30 캜 and an inner temperature of about 60 캜, and then gradually raised by latent heat.

&Quot; Annealing process-S 130 "

Subsequently, the pipe P discharged from the vacuum cooling tank 140 is charged into the annealing tank 150 to spray hot water on the surface thereof, and the pipe is heated by the cooling air discharged through the cooling air discharge pipe 210 P). At this time, the temperature of the heated water is 80 to 100 캜, and the temperature of the cooling air is 20 to 30 캜. The pipe P in the annealing tank 150 has an outer surface temperature of about 80 캜 and an inner temperature of about 70 캜 and a pipe P discharged immediately from the annealing bath 150 has an outer surface temperature of about 80 Lt; RTI ID = 0.0 > 70 C. < / RTI >

&Quot; Cooling process-S140 "

Subsequently, the pipe P discharged from the annealing tank 150 is introduced into the cooling bath 160 to inject cooling water onto the surface of the cooling pipe 160 to cool the pipe P. The cooling air discharged through the cooling air discharge pipe 210 flows into the inside of the pipe P . At this time, the temperature of the cooling water is 10 to 30 캜, and the temperature of the cooling air is 20 to 30 캜. The pipe P in the cooling bath 160 has an outer surface temperature of about 30 캜 and an inner temperature of about 30 캜 and a pipe P discharged immediately from the cooling bath 160 has an outer surface temperature of about 25 Lt; RTI ID = 0.0 > 25 C. < / RTI >

"Printing process-S 150"

Then, the necessary record is printed on the surface of the pipe P discharged from the cooling bath 160 and fed into the inserter 180 through the printer 170. [ At this time, it is preferable that the inside of the pipe P is cooled by the cooling air discharged through the cooling air discharge pipe 210 during the printing process, and the temperature of the cooling air is 20 to 30 占 폚.

&Quot; Corona discharge process-S 160 "

The pipe P passing through the printing machine 170 is then pulled by the pulling machine 180 and the corona discharge is performed on the inner surface of the pipe P discharged from the pulling machine 180 through the corona discharger 190 To process the inner surface of the pipe (P). At this time, the pipe P discharged from the drawing machine 180 has an outer surface temperature of about 20 캜 and an inner temperature of about 20 캜.

&Quot; Cutting process-S170 "

Finally, the pipe passing through the corona discharge device 190 is cut to a predetermined length by the cutter 200 to complete the product. After the visual inspection of the product is completed, it is packed and shipped. At this time, the pipe P discharged from the cutter 190 has an outer surface temperature of about 20 캜 and an inner temperature of about 20 캜.

Hereinafter, an experimental example of a pipe manufactured by the pipe manufacturing apparatus and method capable of removing the residual stress according to the present invention will be described in detail.

FIG. 8 is a perspective view showing a comparison between the heat-treated and non-heat-treated pipes according to the manufacturing method of FIG. 7, FIG. 9 is a graph showing the roughness FIG. 10 is a cross-sectional view of pipes in a heat-treated state and in a non-heat-treated state according to the manufacturing method of FIG.

The pipe manufacturing apparatus 100 capable of removing the residual stress according to the present invention removes the residual stress while uniformizing the structure of the pipe P.

Therefore, the test is performed in three steps to obtain accurate results, and the surface temperature and the outer diameter of the pipe (P) are measured during the heat treatment of the pipe (P) in each test. This is to measure the extent of the jar phenomenon in the finished pipe. Here, the diameter of the finished pipe P is 1000 mm, and the length is 2 m.

First, in the primary test, the surface temperature and outer diameter measured while the pipe (P) passes through the annealing process are shown in Table 1 below. At this time, the cooling water temperature of the vacuum cooling bath 140 is 18 DEG C, the heating water temperature of the annealing bath 150 is 85 DEG C, and the internal temperature of the annealing bath 150 is 83 DEG C. [

The surface temperature and outer diameter of the pipe P in the secondary test are shown in Table 2 below. The temperature of the cooling water in the vacuum cooling bath 140 is 25 占 폚, the temperature of the heating water in the annealing bath 150 is 73 占 폚, and the inside temperature of the annealing bath 150 is 73 占 폚.

The surface temperature and outer diameter of the pipe P in the third test are shown in Table 3 below. At this time, the cooling water temperature of the vacuum cooling bath 140 is 25 占 폚, the heating water temperature of the annealing bath 150 is 95 占 폚, and the internal temperature of the annealing bath 150 is 90 占 폚.

As a result of three tests in the case where the pipe heat treatment is not applied to the pipe P having a diameter of 1,000 mm and the pipe length P of which is made to be 2,000 mm, FIG. 8 shows the result of comparing the width W1 and the width W2 of the both end portions overlapping each other by the jar phenomenon, and the results are shown in Table 4 below.

Also, in the case of the pipe P produced by applying the annealing process as described above, the surface roughness of the pipe P is alleviated as shown in FIG. 9, and the jar phenomenon is removed as shown in FIG. 10 .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood, however, that the invention is not to be limited to the specific forms thereof, which are to be considered as being limited to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. .

110, 120: First and second extruders 130: Dies
140: vacuum cooling bath 150: annealing tank
160: Cooling tank 170: Printing machine
180: inserting 190: corona discharger
200: Cutter 210: Cooling air discharge pipe
220: Cooling air supply 230: Heating water supply
P: pipe

Claims (20)

First and second extruders for melting and discharging the charged synthetic resin material;
A die for supplying the molten resin discharged from the first and second extruders to the outer channel and the inner channel and discharging the pipe from the discharge channel and maintaining the temperature of the inner channel lower than the temperature of the outer channel, ;
A vacuum cooling tank through which the pipe discharged from the die passes and which keeps the outside of the pipe in a vacuum state and injects cooling water onto the surface of the pipe to cool the pipe;
An annealing tank through which the pipe cooled and discharged in the vacuum tank passes, and injects heated water onto the surface of the pipe;
A cooling tank through which the pipe heated and discharged in the annealing tank passes, and injects cooling water into the pipe to re-cool the pipe;
A drawer installed at a rear end of the cooling bath to continuously move the pipe discharged from the die;
A corona discharge unit for discharging corona discharges from the corona discharge unit; a corona discharge unit for discharging corona discharges from the corona discharge unit;
A cutter for cutting the pipe passing through the corona discharge machine to a predetermined length; And
A cooling air discharge pipe extending through the dies and extending along the wire to an electrode of the corona discharge unit and having a plurality of air holes formed therein to spray cooling air introduced from the outside into the pipe, And the residual stress can be removed. The method according to claim 1,
The pipe manufacturing apparatus capable of removing the residual stress,
Further comprising a cooling air supplier for supplying cooling air to the cooling air discharge pipe. The method according to claim 1,
The pipe manufacturing apparatus capable of removing the residual stress,
Further comprising a heating water supplier for supplying heating water at 80 to 100 ° C to the annealing tank and reheating the heated water discharged from the annealing tank to supply residual heat. The method according to claim 1,
The pipe manufacturing apparatus capable of removing the residual stress,
Further comprising a printing machine installed between the cooling bath and the corona discharge machine for printing a necessary record on the surface of the pipe passing through the pipe. The method according to claim 1,
The dice,
A first heater installed on an outer surface of the outer channel to heat the molten resin of the outer channel;
A second heater installed in the inner channel to heat the molten resin of the inner channel;
A guide hole for a cooling air discharge pipe through which the cooling air discharge pipe passes; And
Further comprising an oil cooling coil for preventing an internal temperature from rising above a reference temperature. 6. The method of claim 5,
The oil cooling coil includes:
Wherein the oil is cooled by an oil cooler installed outside and cooled inside, and the heated oil is discharged to the oil cooler. 6. The method of claim 5,
The first heater includes:
Maintaining a temperature of 190 to 220 DEG C,
The second heater
And a temperature of 170 to 180 占 폚 is maintained. The method according to claim 1,
In the vacuum cooling bath,
Characterized in that a plurality of first cooling pipes are provided radially with respect to a center point in the longitudinal direction and cooling water of 10 to 30 DEG C is sprayed to the surface of the pipe through a first nozzle arranged in each of the first cooling pipes The residual stress caused by the residual stress can be removed. The method of claim 3,
The annealing tank may be,
Wherein a plurality of heating pipes are provided radially with respect to a center point in the longitudinal direction and the heating water supplied from the heating water supply device is sprayed onto the surface of the pipe through a second nozzle arranged in each of the heating pipes And removing the residual stress caused by the residual stress. The method according to claim 1,
In the cooling bath,
A plurality of second cooling pipes are provided radially with respect to a center point in the longitudinal direction and cooling water of 10 to 30 DEG C is sprayed to the surface of the pipe through a third nozzle arranged in each of the second cooling pipes The residual stress caused by the residual stress can be removed. The method according to claim 1,
The cooling air discharge pipe
And a heat insulating material is provided on the surface of the pipe. The method according to claim 1,
The pipe
Characterized in that the outer surface temperature is maintained at 190 to 220 DEG C and the inner temperature is maintained at 170 to 180 DEG C at the time of discharging from the die. A pipe manufacturing method using a pipe manufacturing apparatus capable of removing residual stress according to claim 1,
A molten resin supply step of supplying the molten resin of the first extruder to the outer channel of the die and supplying the molten resin of the second extruder to the inner channel of the die;
A pipe discharging step of supplying the outer channel and the inner channel of the die and discharging the pipes by mixing them in the discharge channel and keeping the temperature of the inner channel lower than the temperature of the outer channel;
A vacuum cooling step of injecting a pipe discharged from a die into a vacuum cooling tank to inject cooling water on a surface in a vacuum state to cool the cooling pipe, and cooling the inside of the pipe with cooling air discharged through a cooling air discharge pipe;
An annealing step of injecting the pipe discharged from the vacuum cooling tank into the annealing tank to spray heated water on a surface thereof to cool the inside of the pipe with cooling air discharged through the cooling air discharge pipe;
A cooling step of cooling the inside of the pipe with cooling air discharged through the cooling air discharge pipe by injecting the pipe discharged from the annealing tank into a cooling bath to spray cooling water on the surface thereof;
A corona discharging step of pulling the pipe discharged from the cooling bath with a drawer and performing a corona discharge through a corona discharger on the surface of the pipe discharged from the drawing machine to process the surface; And
And a cutting step of cutting the pipe passing through the corona discharge machine to a predetermined length by a cutter. 14. The method of claim 13,
A pipe manufacturing method capable of removing the residual stress includes:
Further comprising a printing step of printing a necessary record through a printing machine on the surface of the pipe discharged from the cooling bath and input to the drawing machine. 15. The method of claim 14,
The printing process includes:
And cooling the inside of the pipe with cooling air discharged through the cooling air discharge pipe at the same time as printing. 14. The method of claim 13,
The pipe discharging step includes:
Wherein the outer channel of the die is maintained at a temperature of 190 to 220 캜 and the inner channel is maintained at a temperature of 170 to 180 캜. 14. The method of claim 13,
In the annealing step,
Wherein the heating water is supplied to the annealing tank at a temperature of 80 to 100 占 폚 to reheat the heated water discharged from the annealing tank. 14. The method of claim 13,
In the vacuum cooling step,
Wherein the cooling water is sprayed onto the surface of the pipe at a temperature of 15 to 20 占 폚. 14. The method of claim 13,
In the cooling step,
And cooling water of 30 to 40 캜 is sprayed onto the surface of the pipe. 13. A pipe according to claim 13, wherein the pipe is manufactured by a pipe manufacturing method capable of removing residual stress.

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