KR20000024292A - bending method and system for plastic tube using steam - Google Patents

Abstract

PURPOSE: A system is provided to bend a various sized plastic tube when replacing a jig regardless of equipment. CONSTITUTION: A plastic tube bending system comprises a continuous working stand(200) having a jig(210) which installs a plastic tube(100), a steam supplier(300) supplying steam hot deforming the plastic tube by sprayed inside, a chill supplier fixing the plastic tube in a jig shape by spraying compressed chill after hot deforming the plastic tube and a spraying member selectively spraying steam and chill. The jig forms a groove by placing the plastic tube and the groove forms many fixing ring(212) for preventing the plastic tube from separating from the groove after inserting the plastic tube.

Description

Bending method and system for plastic tube using steam

The present invention relates to a plastic tube bending system, and more particularly, to hot deformation by spraying hot steam into a plastic tube mounted on a jig, and then, by pressing compressed cold air to complete the modified bending form. It relates to a plastic tube bending method and a system for shortening.

In general, in the machinery that generates its own power, such as automobiles, metal pipes are frequently used as a connection medium for supplying fuel from a fuel tank to an engine or for transmitting hydraulic pressure in a brake system that provides braking force.

In recent years, such a metal tube is being replaced with a plastic tube. The reason is that the plastic tube is lighter than the metal tube and is excellent in ductility, excellent in workability, and the strength of the plastic tube does not drop compared to that of the metal tube.

In the conventional plastic tube bending system, a plastic tube is mounted on a jig formed in a shape to be bent, inserted into an electric heating furnace of an oven type, and heated for a predetermined time to cause hot deformation in a form in which the plastic tube is mounted on a jig. The plastic tube is bent by cooling by spraying water on the prepared plastic tube.

A conventional plastic tube bending system will now be described with reference to the drawings of a conventional bending system of such a plastic tube.

1 is a process diagram according to a conventional plastic tube bending system, Figure 2 is a schematic diagram showing a bending process according to the conventional plastic tube bending system, Figure 3 is a view showing a jig according to the conventional plastic tube bending system.

As shown, the plastic tube is cut into predetermined lengths. (I)

The cut plastic tube is mounted on the jig 10 and then placed on the pallet 20. (ii) The jig 10 has a groove 11 formed therein so that the plastic tube is inserted and mounted, and the upper side of the groove 11 is mounted. A plurality of hooks 12 are formed therein to prevent the plastic tube inserted into the groove 11 from being separated from the groove 11. And the jig 10 is provided in various forms according to the bending form of the plastic tube. A plurality of jigs 10 are stacked on the pallet 20, and the pallet 20 sequentially passes through the electric heating furnace 30, the cooling and the washing unit 40.

The pallet 20 loaded with the jig 10 is placed in the electric heating furnace 30. (ⅲ) Then, the inside of the electric heating furnace 30 is sealed, and the electric heating furnace 30 is heated. Iii) The electric heat transfer furnace 30 is in the form of an oven, and a heat transfer plate 31 is formed therein, and the plastic tube causes hot deformation by heat generated from the heat transfer plate 31. At this time, the internal temperature of the electric furnace is maintained at 150 ~ 200 ℃, heating time is about 250 seconds.

The hot deformed jig 10 in the electric furnace 30 is moved to the cooling and washing unit for cooling and washing. (V) Cooling and spraying water and air to the inner side of the washing unit 40 in a plastic tube. A plurality of nozzles 41 are formed. The plastic tube hot-deformed in the electric heat transfer furnace 30 is moved, quenched by water sprayed from the nozzle 41 formed inside, and hardened into a deformed form, thereby completing bending. Then, compressed air is injected to remove impurities and water from the outer surface of the plastic tube.

As described above, the plastic tube bend is completed by removing the plastic tube from the jig.

On the other hand, the conventional plastic tube bending system as described above has the following problems.

First, the plastic tube and the jig 10 to which the plastic tube is mounted are simultaneously heated in the electric furnace 30. However, since the jig 10 is made of a metal material, after being heated by heat, rapid quenching is repeatedly caused by water, causing cracking of the jig or thermal deformation, and rust caused by water.

Second, the heat transfer applied to each of the plastic tube located near the heat transfer plate 31 formed in the electric heat transfer furnace 30 and the plastic tube located far from the heat transfer plate 31 is different, thereby uniformly heating the plastic tube located therein. There is a problem in that bending failure occurs.

In addition, the temperature of the furnace is raised to a temperature of 150 ~ 200 ℃ time (250 seconds) for hot deformation of the plastic tube takes a lot of problems that productivity is low.

Third, if the plastic tube to be produced is large, not only the jig 10 to which the plastic tube is mounted should be large, but also the facilities of the electric heating furnace 30 and the cooling and washing unit 40 in which the plastic tube is accommodated will be enlarged. Since there is a problem that the initial cost and maintenance cost at the time of installation takes a lot.

Fourth, there is a problem that the cycle time of a lot (1 LOT) is long, and the amount of plastic tubes to be put into a lot is large enough to provide the jigs required for the lot.

In addition, since water is used to cool the plastic tube, there is a problem that another process is required to remove the water because water remains in the plastic tube.

The present invention has been made to solve the above problems, the manufacturing process and manufacturing time by injecting hot steam into the plastic tube to be mounted on the jig hot deformation and then spraying the compressed cold to complete the modified bending form It is an object of the present invention to provide a plastic tube steam bending system that shortens.

In addition, since the same equipment can be used regardless of the size of the plastic tube to be bent, it is another object to provide a plastic tube steam bending system capable of bending plastic tubes of various sizes when the jig is replaced regardless of the equipment. do.

Figure 1-Process diagram according to the conventional plastic tube bending system

Figure 2-schematic diagram showing the bending process according to the conventional plastic tube bending system

3-Jig showing a conventional plastic tube bending system

4-Schematic diagram showing a plastic tube steam bending system according to the present invention

Figure 5 shows a continuous workbench of a plastic tube steam bending system according to the present invention

6-a jig of a plastic tube steam bending system according to the present invention

7-process diagram showing a plastic tube bending method using a plastic tube steam bending system according to the present invention

<Explanation of symbols for main parts of the drawings>

100: plastic tube 200: continuous workbench

210: jig 211: groove

212: hook 220: turntable

230: workbench 300: steam supply device

310: boiler 311: water tank

312: water softener 313: hot water storage tank

314: oil tank 320: steam distribution

321: steam distribution port 322: steam tank

330: pressure reducing valve 331: pressure gauge

340: first opening and closing valve 400: cold air supply device

410: air compression unit 420: first filtering unit

430: air dryer 440: second filtering unit

450: second opening and closing valve 500: injection member

510: Tee fitting 520: Nozzle connection

521: distribution port 522: flow pipe

530: nozzle 540: discharge pipe

Plastic tube spitting system according to the present invention for achieving the above object is a jig of a predetermined shape is installed, the continuous workbench for bending the plastic tube according to the shape of the jig; A steam supply device for injecting steam at a predetermined pressure into the plastic tube; A cold air supply device for forcibly injecting compressed cold air of a predetermined pressure into the plastic tube; And an injection member coupled to the steam supply device and the cold air supply device and coupled to one end of the jig to selectively supply steam and cold air into the plastic tube. It is a technical aspect of the present invention to provide a plastic steam bending system characterized in that the plastic tube is hot-deformed by hot steam, and the compressed plastic air is bent into a predetermined shape by supplying compressed cold air into the hot-deformed plastic tube. .

Here, the continuous work table, the turntable is rotated; And it is provided on the side of the turntable, the work table on which the jig is installed is mounted on the plastic tube on the upper side; It is preferably configured to further include.

And, the steam supply device and the boiler for generating steam; A steam distribution unit for storing a predetermined amount of steam generated in the boiler unit and distributing steam to a plurality of distribution ports; Pressure reducing valve for maintaining the steam supplied through the distribution port of the steam distribution unit at a constant pressure; And a first opening / closing valve for supplying steam maintained at a constant pressure while passing through the pressure reducing valve into the plastic tube and shutting off.

In addition, the cold air supply unit and the air compression unit for extruding the outside air; A first filtering part for purifying the air compressed by the air compression part; An air dryer for maintaining the compressed air purified by the first filtering unit below a predetermined temperature; A second filtering unit for purifying the compressed air supplied from the air dryer again; And a second opening / closing valve for opening and closing the compressed air supplied from the second filtering unit.

And, the injection member is a tee type fitting is coupled to the first opening and closing valve and the second opening and closing valve; A nozzle connection unit coupled to one side of the tee fitting and configured to supply steam and cooling compressed air supplied through the first opening / closing valve and the second opening / closing valve; And a nozzle connected to the nozzle connection part and the flow pipe and connected to the end of the plastic tube to supply steam and cooling compressed air supplied through the nozzle connection part to the inside of the plastic tube.

According to the plastic tube bending steam bending method according to the invention, the first step of mounting the plastic tube on the jig installed in the continuous workbench; Connecting the nozzle to an end of the jig in which the plastic tube is mounted; Inject the steam supplied from the steam supply device into the plastic tube combined with the nozzle through the nozzle to hot deform the plastic tube, and compress the cold air supplied from the cold air supply device (0 to 5 ° C) into the hot deformed plastic tube. A third step of quenching the hot-deformed plastic tube by spraying to complete bending of the plastic tube in the shape of a jig; A fourth process of separating the nozzles coupled to the ends of the bent plastic tube in the third process, and a fifth process of removing the bent plastic tube in the shape of the jig from the jig; It is a technical point to provide a bending method.

Accordingly, the present invention has the advantage of shortening the manufacturing process and manufacturing time by injecting hot steam into the plastic tube mounted on the jig to hot deform and then spraying the compressed cold to complete the modified bending form.

Plastic tube steam bending system according to the present invention as described above will be described with reference to the drawings.

Figure 4 is a schematic view showing a plastic tube steam bending system according to the present invention, Figure 5 is a view showing a continuous workbench of the plastic tube steam bending system according to the present invention. 6 is a view showing a jig of the plastic tube steam bending system according to the present invention.

The plastic tube bending system is supplied to the continuous worktable 200 with the jig 210 on which the plastic tube 100 is mounted, and the steam supply for supplying steam for hot deformation of the plastic tube 100 by being injected into the plastic tube 100. After the apparatus 300 and the plastic tube 100 are deformed by steam, the cold air supply device 400 for spraying compressed cold air to fix the shape of the plastic tube 100 in the form of a jig 210 and steam and It consists of an injection member 500 for selectively injecting cold air.

Continuous working table 200 is composed of a turntable 220 of a hexagonal shape that is rotated, a work table 230 formed on three non-corresponding sides of the turn table 220, jig 210 provided on the work table 230.

The turntable 220 is formed to be rotated about a central axis in a hexagonal shape, and the work table 230 is formed outward on three sides that are not corresponding.

The working table 230 is formed on three sides of the turntable 220, and the jig 210 to which the plastic tube 100 is mounted is installed.

Jig 210 is a plastic tube 100 is mounted is bent to be made of a shape to be bent. The jig 210 has a groove 211 formed in a predetermined shape with the plastic tube 100 positioned therein, and the plastic tube 100 is inserted into the groove 211 after the plastic tube 100 is inserted into the groove 211. In order to prevent the deviation from the plurality of hooks 212 is formed on the upper side of the groove 211. And, both ends of the jig 210 is formed with a nozzle 530 coupling portion is coupled to the nozzle 530 is coupled to one end by the coupling method, the other end is injected into the plastic tube 100 inside the plastic tube The discharge pipe 540 is coupled to the hot water storage tank 313 through the discharge pipe 540 by the coupling method so that the steam that hot-deformed 100 may be collected and recycled.

The workbench 200 rotated as described above is divided into subdivisions, and the work is carried out. The mounting work for mounting the plastic tube 100 to the jig 210 in the workbench 230 formed on three sides of the workbench 200 is performed. Bending, and the stripping process is performed continuously by the rotation of the continuous work platform (200). When the plastic tube 100 is mounted on the jig 210 formed in a predetermined shape, and the mounting of the plastic tube 100 is completed, the continuous working table 200 is rotated to inject the injection member 500 at the end of the plastic tube 100. Combining the nozzle 530 of the plastic tube 100, the steam and compressed cold air is injected into the bend. Then, when the bending of the plastic tube 100 is completed, the mounting, bending and stripping operation to remove the plastic tube 100 by rotating the continuous working table 200 is rotated while working platform 230 formed on three sides Is done.

The steam supply device 300 is supplied from a boiler unit 310 for generating steam for hot deformation of the plastic tube 100, a steam distribution unit 320 for distributing steam supplied from the boiler, and a steam distribution unit 320. A pressure reducing valve 330 for maintaining steam at a constant pressure, and the first opening and closing valve 340 for blocking and supplying the steam supplied through the pressure reducing valve 330.

The boiler unit 310 for generating steam uses a commonly used oil or gas steam boiler facility, and the boiler facility includes a water tank 311 for storing water and water contained in the water tank 311. Water softener 312 for removing impurities such as metal and heavy metal components, hot water storage tank 313 is stored after the water generated in the water purifier and the steam circulated in the boiler 313, oil tank in the case of oil boiler ( 314) and the boiler body. Boiler facilities as described above are basically provided when the boiler is installed, so detailed description thereof will be omitted.

Steam distribution unit 320 is generated by the operation of the steam boiler as described above to distribute the steam supplied through the steam boiler of the steam boiler, the steam tank 322 and the steam tank 322 is stored a certain amount of steam It is composed of a plurality of steam distribution port 321 formed on the top. The steam tank 322 always stores a certain amount of steam to continuously supply steam through the steam distribution port 321. Then, the plurality of steam distribution port 321 supplies the steam stored in the steam tank 322 to each line. Due to the steam distribution port 321, the steam generated in one boiler can be supplied to a plurality of continuous workbench 200, not only to use steam efficiently, but also to reduce the production equipment, thereby producing the plastic tube 100. The cost can be lowered.

Steam supplied through the steam distribution port 321 of the steam distribution unit 320 passes through the pressure reducing valve 330. The pressure reducing valve 330 functions to reduce the pressure of the steam supplied to a predetermined pressure and keep it constant. Since the steam passing through the pressure reducing valve 330 is injected into the plastic tube 100 at a constant pressure, the bending of the plastic tube 100 is made constant so that the high temperature and the pressure of steam are uniformly distributed inside the plastic valve. To increase the effect. In addition, when the pressure reducing valve 330 malfunctions or has an abnormality, a preliminary pressure reducing valve 330 'is separately installed to maintain a constant pressure. And the pressure gauge 331 is provided in the position adjacent to the pressure reduction valve 330, and shows the pressure of the steam which passed through the pressure reduction valve 330 numerically, and observes whether a pressure is constant.

The steam passing through the pressure reducing valve 330 is supplied or blocked by the first opening / closing valve 340 into the plastic tube 100. The first opening / closing valve 340 is a valve operated by being controlled by an electrical signal.

The components of the steam supply device 300 as described above are connected to each other by a pipe pipe, and the pipe pipe surrounds the outside with a heat insulating material to isolate the outside and the pipe pipe to maintain a temperature of steam.

The cold air supply device 400 is filtered by an air compression unit 410 for compressing external air, a first filtering unit 420 for filtering compressed air compressed by the air compression unit 410, and a first filtering unit 420. An air dryer 430 for maintaining the compressed air below a predetermined temperature, a second filtering unit 440 for filtering the compressed cold air passing through the air dryer 430 again, and blocking the compressed cold air supplied through the filtering unit. It is composed of a second opening and closing valve 450 to supply.

The air compressor 410 uses an air compressor (not shown) to compress external air. A compressor (not shown) stores compressed air in a pressure tank provided inside the compressor by sucking and compressing external air. Compressor is generally widely used and detailed description thereof will be omitted.

The outside air compressed by the air compressor 410 passes through the first filtering part 420. The first filtering unit 420 has an internal air filter (not shown) therein, and when compressed air passes through, the impurities contained in the compressed air are removed.

Compressed air from which the impurities are removed from the first filtering part 420 passes through the air dryer 430. The air dryer 430 is a drying facility, and is provided with a cooling fan therein to remove moisture contained in the compressed air and to cool the compressed air to maintain the temperature at 0 to 5 ° C. The reason for maintaining the temperature of the compressed air at 0 to 5 ° C is to optimize the cooling efficiency of the plastic tube 100 hot-deformed by steam. This data is the result of a myriad of experiments as the designer installed the plant.

The compressed air cooled while passing through the air dryer 430 removes residual impurities while passing through the second filtering unit 440. The second filtering unit 440 uses the same air filter (not shown) used in the first filtering unit 420.

The compressed cold air as described above is injected into or blocked by the plastic tube 100 by the second opening / closing valve 450. The second open / close valve 450 uses the same as the first open / close valve 340 and is controlled and operated by an electrical signal.

The components of the cold air supply device 400 as described above are connected to each other by a pipe pipe and pass through the air dryer 430 to maintain the temperature of the compressed cold air maintained at a temperature of 0 to 5 ° C. ) And the second filtering part 440 and the second opening and closing valve 450 surround the outside with a heat insulating material to isolate the outside and the pipe pipe to maintain the temperature of the compressed cold air at a constant temperature.

The injection member 500 couples the steam supply device 300 and the cold air supply device 400 to inject steam and compressed cold, which are selectively supplied, into the plastic tube 100 through one nozzle 530. The injection member 500 includes a tee fitting 510 coupled to the first opening / closing valve 340 and a second opening and closing valve 450, a nozzle connecting portion 520 and a nozzle connecting portion 520 coupled to the tee fitting 510. It is composed of a nozzle 530 connected to the end of the plastic tube 100.

The tee fitting 510 has a ┻ shape and has a first coupling part, a second coupling part, and a third coupling part. The first coupling part and the second coupling part are coupled to the first open / close valve 340 and the second open / close valve 450, respectively, so that the steam and the compressed cold air of the first open / close valve 340 and the second open / close valve 450 are separated. Operation is optionally supplied into the tee fitting 510. In addition, the third coupling part of the tee fitting 510 is coupled to the nozzle connection part 520.

One side of the nozzle connection portion 520 is coupled to the third coupling portion of the tee fitting 510, and a plurality of distribution holes 521 are formed on the outer circumferential surface of the nozzle connection portion 520, and selectively supplied steam and compressed cold air through the nozzle 530. Spray into the plastic tube (100). In addition, a flow pipe 522 coupled to the nozzle 530 is coupled to the distribution port 521. The reason why the flow pipe 522 is coupled is to simplify the detachment of the nozzle 530 since the pipe is frequently moved while the nozzle 530 is detached from the plastic tube 100.

The end of the flow pipe 522 is coupled to the nozzle 530 for injecting steam and compressed cold air into the plastic tube 100, the coupling is formed in the nozzle 530, the plastic tube 100 is mounted It is coupled to the end of the jig 210 is connected. In this way, the steam and compressed cold air supplied through the nozzle 530 are injected into the plastic tube 100 without leaking to the outside. Then, the discharge pipe for collecting the steam is injected into the plastic tube 100 through the nozzle 530 to hot-deform the plastic tube 100 is coupled. The discharge pipe is connected to the hot water storage tank 313 of the steam boiler 310 to recycle steam.

As shown in the above description, the plastic tube 100 steam bending system according to the present invention does not require a conventional electric heating furnace, and also requires no cooling and washing machine. Therefore, the electric heating furnace and the cooling and washing facilities are unnecessary, and the manufacturing cost for constructing the system is reduced. Instead of the electric heating furnace and the cooling and the washing machine in the present invention, since the steam supplied from the steam supply device 300 and the compressed cold air supplied from the cold air supply device 400 are used, the work process is simplified and the working time is shortened. , Because steam and compressed air is directly injected into the plastic tube 100, workability is improved, and bending defects of the plastic tube 100 are reduced, thereby improving productivity.

The manufacturing method by the plastic tube steam bending system according to the present invention having the configuration as described above will be described with reference to the drawings.

7 is a process chart showing a plastic tube steam bending method according to the present invention.

First, a steam supply device 300 for supplying steam and a cold air supply device 400 for supplying compressed cold air are operated in a preliminary process so that steam and compressed cold air can be supplied.

The plastic tube 100 is mounted on the jig 210 installed on the work bench 230 formed in the continuous work table 200. (I) The plastic tube 100 is inserted into the groove formed in the jig 210, and the The plastic tube 100 is not detached from the groove of the jig 210 by a plurality of hooks 212 formed on the upper side.

Coupling the nozzle 530 to which steam and compressed cold air are continuously supplied to one end of the jig 210 on which the plastic tube 100 is mounted. (II) Coupling one end of the jig 210 to the nozzle 530. The coupling method is used and can be easily separated and combined with one touch. And, the other end of the jig 210 is connected to the discharge pipe is injected into the plastic tube 100 is discharged steam and compressed cold air is recovered.

Steam and compressed cold air is sequentially sprayed into the plastic tube 100 coupled to the nozzle 530. (III) Steam is supplied through the spray member 500 from the steam supply device 300, and compressed cold air Is injected into the plastic tube 100 through the injection member 500 in the cold air supply device 400 is injected. Steam supplied from the steam supply device 300 is injected into the plastic tube 100 at a temperature of 120 ~ 180 ℃ and a pressure of 6 ~ 10kg / ㎠. The compressed cold air supplied from the cold air supply device 400 is injected into the plastic tube 100 at a temperature of 0 to 5 ° C. and a pressure of 7 to 8 kg / cm 2.

As described above, the plastic tube 100 is hotly deformed by steam supplied into the plastic tube 100, and the injection of steam is performed for 20 seconds. Then, compressed cold air is supplied into the hot deformed plastic tube 100 to quench the plastic tube 100. At this time, the injection of the compressed cold air is made for 15 seconds. As such, the plastic tube bending using steam and compressed cold air takes about 240 to 250 seconds to heat the electric furnace and 20 seconds to cool down and cleans it. This is more than five times shorter, which improves productivity.

In addition, since the inside of the plastic tube 100 is directly heated and cooled, there is no need for an external cleaning process of the plastic tube 100 as in the prior art, and the water remaining in the plastic tube 100 needs to be removed during the cleaning process. There is no.

The nozzle 530 is separated at one end of the jig 210 where the bending is completed, and the discharge pipe is separated at the other end.

Then, when the plastic tube 100 that is bent in the shape of the jig 210 is removed from the jig 210, the bending of the plastic tube 100 is completed.

Steam bending operation of the plastic tube 100 as described above is made in the continuous working platform (200). Work is proceeded by dividing the three-part (3part) as the continuous working table 200 is rotated, 1PART for mounting the plastic tube 100 on the jig 210, steam on the plastic tube 100 mounted on the jig 210 After steaming the plastic tube 100 by hot deformation, 2PART for completing the bending of the plastic tube 100 hot-deformed by spraying compressed cold, and jig (100) the plastic tube 100 is completed bending in 2PART ( It is separated into 3PART to be removed from 210, the mounting, bending and stripping process of the plastic tube 100 is carried out continuously.

As described above, in the steam bending method according to the present invention, since one cycle time takes about 40 seconds or less, one cycle time in a conventional electric oven method requires more than 300 seconds, thereby significantly reducing work time and improving productivity. This is improved, and since the supply of steam and compressed cold air directly and uniformly directly inside the plastic tube 100, there is almost no bending defect rate of the plastic tube 100, and the productivity is improved as compared with the conventional method as a whole.

As described above, according to the steam bending method of the plastic tube according to the present invention, the bending process of the plastic tube is simplified, the manufacturing time is shortened, the productivity is improved and the manufacturing cost accordingly has the advantage.

In addition, since the same equipment can be used regardless of the size of the plastic tube to be bent, replacing the jig regardless of the equipment has the advantage of bending plastic tubes of various sizes.

In addition, since the bending by direct injection of steam and compressed cold air into the plastic tube there is an advantage that there is no fear of occurrence of bending failure, there is an advantage that the productivity is improved.

Claims (6)

A jig 210 having a predetermined shape is installed and a continuous work table 200 for bending the plastic tube 100 according to the shape of the jig 210; A steam supply device 300 for injecting steam at a predetermined pressure into the plastic tube 100; A cold air supply device 400 for forcibly injecting compressed cold air of a predetermined pressure into the plastic tube 100; And It is coupled to the steam supply device 300 and the cold air supply device 400, the injection member 500 is coupled to one end of the jig 210 is selectively supplied with steam and cold air into the plastic tube 100 It is configured to include; and steam and compressed cold air selectively injected into the plastic tube 100, hot deformation of the plastic tube 100 by hot steam, the compression inside the hot-deformed plastic tube 100 Plastic tube steam bending system, characterized in that for supplying cold air to bend in a predetermined shape. According to claim 1, The continuous working table 200, A turntable 220 that is rotated; And The working table 230 is provided on the side of the turntable 220, the jig 210 is installed on the plastic tube 100 is mounted on the upper side; plastic tube bending system further comprises. The method of claim 1, wherein the steam supply device 300 A boiler unit 310 for generating steam; A steam distribution unit 320 in which steam generated in the boiler 310 is stored in a predetermined amount and steam is distributed to a plurality of steam distribution ports 321; A pressure reducing valve 330 for maintaining the steam supplied through the steam distribution port 321 of the steam distribution unit 320 at a constant pressure; And And a first opening / closing valve (340) for supplying the steam maintained at a constant pressure while passing through the pressure reducing valve (330) into the plastic tube (100), and shutting off the plastic tube steam bending system. According to claim 1, wherein the cold air supply device 400 An air compression unit 410 through which external air is extruded; A first filtering part 420 for purifying the air compressed by the air compression part 410; An air dryer 430 for maintaining the compressed air purified by the filtering unit below a predetermined temperature; A second filtering part 440 for purifying the compressed air supplied from the air dryer 430 again; And And a second open / close valve (450) for opening and closing the compressed air supplied from the second filtering unit (440). The method of claim 1, wherein the injection member 500 A tee fitting 510 to which the first open / close valve 340 and the second open / close valve 450 are coupled; A nozzle connection portion 520 coupled to one side of the tee fitting 510 and supplying steam and cooling compressed air supplied through the first opening / closing valve 340 and the second opening / closing valve 450; And It is connected by the nozzle connector 520 and the flow pipe 522, and is connected to the end of the plastic tube 100 to supply steam and cooling compressed air supplied through the nozzle connector 520 to the inside of the plastic tube Nozzle 530; plastic tube bending system characterized in that consisting of. A first process of mounting the plastic tube 100 on the jig 210 installed on the continuous work bench 200; A second process of connecting the nozzle 530 to an end of the jig 210 on which the plastic tube 100 is mounted; Inject the steam supplied from the steam supply device 300 into the plastic tube 100 coupled to the nozzle 530 through the nozzle 530 to hot deform the plastic tube 100, and to hot deform the plastic tube 100. ) The compressed cold air supplied from the cold air supply device 400 (0 ~ 5 ° C) is injected into the inside to quench the hot deformed plastic tube 100 to complete the bending of the plastic tube 100 in the shape of the jig 210. A third process of becoming; A fourth process of separating the nozzle 530 coupled to the end of the plastic tube 100 where the bending is completed in the third process; And a fifth process of removing the plastic tube (100) bent from the jig (210) to the shape of the jig (210).