KR20140069472A - Coating device for inner surface of ductile cast iron pipe by thermoplastic resin powder and the thermoplastic resin powder coated ductile cast iron pipe - Google Patents

Abstract

The present invention relates to an apparatus for coating an inner surface of a cast iron pipe and a cast iron pipe coated with a thermoplastic resin powder paint. The apparatus for coating an inner surface of a cast iron pipe for painting a thermoplastic resin powder paint comprises the following components. A transfer assembly horizontally transfers the cast iron pipe through a transfer conveyor. A plurality of rotating assemblies are installed at the lower portion of the transfer assembly such that the cast iron pipe is rotated by using a plurality of rotating rollers and an elevating cylinder. A push assembly pushes the upper portion of the cast iron pipe which is rotated through the rotating assemblies by using an air cylinder and an idle roller which is installed at the end portion of the air cylinder. A polishing assembly polishes an inner portion of the cast iron pipe which is rotated by the rotating assemblies. Further, the polishing assembly polishes the inner circumferential surface of the cast iron pipe by using a polishing stone which is installed at an end portion of a polishing shaft mounted on a polishing table. A foreign matter removing assembly removes foreign matters from the inside of the cast iron pipe by using compressed air sprayed through a nozzle which is installed at the end portion of an air spray pipe. A socket cleaning assembly removes foreign matters from a cast iron pipe socket which is rotated by the rotating assemblies by using a nozzle mounted on a rotating fixture. A heating furnace heats the cast iron pipe which is transferred through the transfer conveyor. A socket unit and outer cross sectional section painting assembly paints a socket unit and an outer cross sectional section of the cast iron pipe, which passed through the heating furnace, by using an electrostatic spray gun. A powder painting assembly paints the inner surface of the cast iron pipe by using a nozzle installed at the end portion of a painting pipe.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner surface coating device for a thermoplastic resin powder coating and a cast iron tube coated with a thermoplastic resin powder coating,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cast iron pipe inner surface coating apparatus and a cast iron pipe for coating a thermoplastic resin powder coating, and more particularly, to a cast iron pipe obtained by grinding the inner surface of a cast iron pipe and coating the inner surface with a thermoplastic resin powder coating.

Cast iron pipes are mainly used for transportation of water and sewage pipes and other liquids, and are mostly produced by centrifugal casting.

Since the cast iron pipe manufactured by the centrifugal casting method is embedded in the underground, the inner and outer circumferential surfaces are coated so as to withstand various external environments.

The coating material used for such a coating is a liquid or powder. The cement mortar lining or the epoxy powder coating material has already been developed and used as a corrosion preventive coating material for an inner surface of a cast iron pipe.

Epoxy powder coatings are widely used because of their excellent durability, processability and adhesive strength to a conductor, and also have high mechanical and chemical resistance. However, liquid paint has problems such as air pollution and water pollution due to volatile organic compounds during manufacture and use Or the safety of workers, and BPA epoxy resin has been constantly raising controversy about human health. Recently, in order to solve the problems of such liquid epoxy paints, a method of coating an epoxy resin powder paint which has no volatile organic compounds on the inner surface of a cast iron pipe has been developed and used.

In this case, the surface of the cast iron pipe is pre-treated so that the paint is adhered well, and the cast iron pipe is pre-heated to about 160 ° C. to about 380 ° C. by using a gas oven or an induction coil.

Next, the preheated cast iron tube is rotated at a constant speed, and the spray nozzle is inserted therein to spray the powder coating material so as to have a uniform thickness, thereby attaching the powder coating material to the surface of the cast iron tube. And then hardened.

In such a process, a powder paint spraying operation is performed by inserting an elongated supply pipe equipped with a nozzle into the cast iron pipe when coating the inner surface of a steel pipe or a cast iron pipe.

Prior art related to the epoxy powder coating tube and the manufacturing technology include Application Nos. 10-2006-0075736 and 10-2009-0024732 filed in the Korean Intellectual Property Office.

However, the cast iron pipe is difficult to uniformly polish the inner surface during the polishing process for coating, and it is difficult to completely remove the foreign substances generated in the polishing process.

In addition, the cast iron pipe has a socket for connection at the end portion, foreign matter is likely to remain at the portion, and it is difficult to coat the inner surface and the end portion of the socket at the inner surface coating process. In addition, there is controversy about environmental hazard in the case of BPA type epoxy paint which is widely used.

It is an object of the present invention to provide a coating device capable of improving the performance and quality of a coating surface by automating a coating process, in a cast iron pipe inner coating device for coating a thermoplastic resin powder coating.

In addition, thermoplastic resin powder paint made by bonding metal ion (Na or Zn) to ethylene methacrylic acid (EMAA) is coated on the inner surface of a ductile tile cast iron tube, so there is no controversy about human harmfulness. And has improved coating performance such as coating adhesion, abrasion resistance, anticorrosiveness, chemical resistance and UV safety.

It is another object of the present invention to provide a coating apparatus capable of efficiently polishing and coating an inner surface of a cast iron pipe for coating and completely removing foreign matters generated in a polishing process to produce a thermoplastic resin powder coating- .

The present invention relates to a cast iron inner surface coating apparatus for coating a thermoplastic resin powder coating, which comprises a transfer assembly for horizontally conveying a cast iron pipe through a conveying conveyor, a lower conveying assembly for rotating the cast iron pipe using a plurality of rotating rollers, A pressing assembly for pressing an upper portion of a cast iron pipe rotated through the rotary assembly using an air cylinder and an idle roller installed at the end of the air cylinder; An abrasive assembly for abrading the inner circumferential surface of the cast iron through a grindstone provided at an end of the abrasive shafts mounted on the abrading bogie; a foreign matter removing assembly for removing foreign matter from the inside of the cast iron tube using compressed air injected through a nozzle provided at an end of the air- time A socket assembly cleaning assembly for removing foreign objects from a socket of a cast iron pipe rotated through the rotary assembly using a nozzle mounted on a jig, a heating furnace for heating a cast iron pipe moved through the conveying conveyor, And a powder coating assembly for coating the inner surface of the cast iron tube through a nozzle provided at an end of the coating tube. The powder coating assembly includes a socket portion and an outer end surface coating assembly for coating the socket portion and the outer end portion using a powder coating gun.

The pressing assembly includes an air cylinder and a position sensor mounted on the end of the air cylinder and moving up and down to contact the outer circumferential surface of the cast iron pipe and sensing the position of the idler roller, And a proximity sensor for confirming whether or not the microcomputer is operating normally.

Here, the transfer assembly includes a chain installed on the conveyor frame, a bracket installed on the chain so that the cast iron pipe is seated, and a drive motor for driving the chain.

The foreign matter removing assembly includes a rail extending horizontally, a cleaning carriage installed on the rail, a height adjusting portion provided on the cleaning carriage, an air spraying pipe installed on the height adjusting portion, And a nozzle provided at the end portion.

The socket portion cleaning assembly includes a rotary fixture to which the nozzle is mounted, and a drive motor that operates the rotary fixture.

In addition, the socket portion and the outer end face coating assembly may include a transporting carriage provided with the electrostatic powder coating gun, a robot cylinder for horizontally moving the transporting carriage, a driving wheel, and a servo motor for controlling the height of the transporting carriage .

The powder coating assembly may include a rail extending horizontally, a moving carriage installed on the rail, a height adjusting unit installed on the moving carriage, a coating pipe installed on the height adjusting unit, And a nozzle installed therein.

Finally, a thermoplastic resin powder coating prepared by bonding a metal ion (Na + or Zn +) to ethylene methacrylic acid (EMAA) is coated on the inner surface using a cast iron pipe inner coating apparatus for coating a thermoplastic resin powder coating, and an outer surface is coated with an asphalt coating Or thermoplastic resin powder coating painted with modified alkyd paints.

The inner surface coated abrasive apparatus for casting a thermoplastic resin powder coating according to the present invention abrades an outer surface of a cast iron tube by a push assembly while polishing the inner surface while rotating the cast iron tube to reduce vibrations caused by ellipses, It is possible to perform efficient polishing, and coating is performed in an excellent state of the inner surface pretreatment, thereby improving the adhesion of the coating film and the quality of the coating.

The inner surface foreign material removing device can improve the performance and quality of the coated surface by effectively removing the foreign matter from the socket portion as well as the inner surface of the main body and automating the coating process through the assembly for performing the coating process of the inner surface of the socket and the end surface There is an advantage that a coating apparatus can be provided.

Further, a thermoplastic resin powder coating made by bonding metal ion (Na or Zn) to ethylene methacrylic acid (EMAA) is melt-coated on the inner surface of a duck tile cast iron tube by using the above-described coating apparatus to have a uniform film thickness But it has the advantage of forming a coating film which is excellent in anticorrosion, abrasion resistance and UV safety, and has no environmental hazard, by increasing the adhesion of the metal surface and the paint.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flowchart showing a coating process using a cast iron pipe inner surface coating apparatus for coating a thermoplastic resin powder coating according to a preferred embodiment of the present invention. FIG.
2 is a front view showing a transfer assembly of a cast iron pipe inner coating apparatus for coating a thermoplastic resin powder coating according to a preferred embodiment of the present invention.
3 is a plan view showing a polishing assembly according to a preferred embodiment of the present invention;
4 is a side view illustrating a rotating assembly and a push assembly in accordance with a preferred embodiment of the present invention.
5 is a side view showing a foreign matter removing assembly according to a preferred embodiment of the present invention.
6 is a side view showing a socket portion cleaning assembly according to a preferred embodiment of the present invention.
7 is a side view showing a heating furnace according to a preferred embodiment of the present invention;
FIG. 7A is a front view of FIG. 7; FIG.
8 is a side view showing a socket portion and an outer end face coating assembly according to a preferred embodiment of the present invention.
9 is a side view showing a powder coating assembly according to a preferred embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart showing a coating process using a cast iron pipe inner surface coating apparatus for coating a thermoplastic resin powder coating according to a preferred embodiment of the present invention.

As shown in FIG. 1, the coating process using the inner surface coating apparatus for a cast iron tube for coating a thermoplastic resin powder coating according to the present invention is performed through the steps of product transportation, internal polishing, foreign matter removal, preheating, end coating, And a marking process.

The inner surface coating apparatus for a cast iron pipe for coating a thermoplastic resin powder coating according to the present invention comprises a transfer assembly, a plurality of rotary assemblies, a pressing assembly, a polishing assembly, a debris removal assembly, a socket portion cleaning assembly, a heater, a socket portion, And a powder coating assembly.

First, the transfer assembly horizontally moves the cast iron pipe to be coated horizontally according to the entire process sequence.

2 is a front view showing a transfer assembly of a cast iron pipe inner coating apparatus for coating a thermoplastic resin powder coating according to a preferred embodiment of the present invention.

As shown in FIG. 2, the conveying assembly according to the present invention horizontally conveys the cast iron pipe through the conveying conveyor. The conveyor assembly includes a chain 26 installed on the conveyor frame 25 and a bracket 27 on which the cast iron pipe is seated. And the cast iron pipe is horizontally moved when it is rotated through the drive motor 21. [

Therefore, the cast iron pipe to be coated is put on the bracket 27 of the transfer assembly using the pipe conveyance carriage, and the cast iron pipe is horizontally moved through the conveying conveyor to perform the polishing and painting process.

The drive motor 22 provided at one side transmits power to the rotary shaft 29 through the chain coupling 23 and drives the chain through both sprockets 24 fixed to the rotary shaft. And the cast iron pipe is moved by the process through the bracket 27 fixed to the chain.

At this time, a rotation sensing gear and a sensor are installed on the rotary shaft 29 to sense the rotation of the rotary shaft once per rotation, thereby allowing the transfer assembly to decelerate and stop so that the cast iron pipe can be moved by the process. It is preferable to provide a tension adjusting screw so that the tension of the chain can be adjusted.

4 is a side view illustrating a rotating assembly and a push assembly in accordance with a preferred embodiment of the present invention.

A plurality of rotating assemblies are installed below the transfer assembly to rotate the cast iron tube using a plurality of rotating rollers and a lifting cylinder, and the pushing assembly includes an air cylinder and idler rollers installed at the end of the air cylinder, And presses the upper portion of the cast iron pipe to be rotated.

4, the cast iron pipe 3, which is moved along the movement of the chain 26, is rotated through the rotating assembly 130, and is guided to rotate the cast iron pipe 3 to guide the stable rotation of the cast iron pipe 3 to be rotated. The upper surface is pressed to prevent the cast iron pipe from flowing or departing.

The rotating assembly 130 includes a plurality of rotating rollers 131 and an ascending and descending cylinder 132. The rotating assembly 130 is moved up and down through a lifting cylinder 132 to be in contact with a cast iron pipe to be rotated, (131) is rotated by a frictional force.

The pressing assembly 150 includes an air cylinder 154 and an idler roller 151 installed at an end of the air cylinder 154 to press the upper surface of the cast iron pipe to be rotated.

4, a roller guide 152, a driving motor 155, an LM guide 156, and a position sensor 157 are provided in addition to the idle roller 151 and the air cylinder 154. [ And the position of the idle roller 151 is automatically determined by the position detection sensor 157 in accordance with the size of the cast iron pipe and the idle roller 151 is mounted at the end of the air cylinder 152 to rotate the pipe So that it can be effectively supported by vibration or flow caused by internal polishing.

The proximity sensor 154 is installed at one side of the idle roller 151 and when the idle roller 151 contacts the upper surface of the cast iron pipe, the roller guide 153 is ascended and sensed to check whether the idle roller is operating normally.

Next, the polishing assembly will be described.

3 is a plan view showing a polishing assembly according to a preferred embodiment of the present invention.

As shown in FIG. 3, the polishing assembly installed perpendicular to the casting direction of the cast iron pipe serves to polish the inner circumferential surface of the cast iron tube through the grindstone provided at the end of the grinding shaft mounted on the grinding carriage, through the cast iron pipe rotated through the rotating assembly .

In order to coat (coat) the inner surface of the cast iron pipe, it is necessary to perform an effective inner surface cutting process in the inner surface preprocessing step, and the inner surface of the cast iron pipe rotating at a constant speed above the rotary assembly 130 composed of the plurality of rotating rollers and the ascending / 145 to rotate the grinding stone 14 rotating at a high speed.

At this time, the length of the polishing shaft 142 is made longer than 1/2 of the length of the cast iron pipe, and it is preferable that two polishing assemblies are provided on both sides of the cast iron pipe and polished at the same time.

That is, when the grinding bogie 145 advances from one side of the cast iron pipe and the inner surface of the cast iron pipe is started to be cut, the grinding bogie is advanced at the opposite side with a certain time difference, .

3, the grinding assembly 140 is provided with a grinding stone 141 at the end of the grinding shaft 142 rotated through the driving motor, and the grinding shaft is moved through the horizontally installed rails 149 And is installed in the truck 145.

Accordingly, the inner surface of the cast iron pipe rotated through the rotating assembly 130 is moved horizontally while polishing the inner surface.

Next, the foreign matter removing assembly will be described.

5 is a side view showing a foreign matter removing assembly according to a preferred embodiment of the present invention.

5, the foreign substance removing assembly 210 includes a rail 216 installed horizontally, a cleaning truck 219 installed on the rail 216, and a height adjustment unit 220 installed on the cleaning truck 219. [ An air injection pipe 212 installed at the height adjustment part 214 and a nozzle 211 installed at an end of the air injection pipe 212. [

The high pressure compressed air is injected through the nozzle 211 through the spray tube 212 provided on the inner surface cleaning truck 219 to remove foreign matter remaining inside the polished cast iron tube through the polishing assembly.

At this time, a height adjusting portion (using an LM guide) 214 is installed in the jetting tube fixing portion 217 of the cleaning carriage 219 so that the height of the jetting nozzle can be adjusted according to the size of the cast iron pipe 3, A motor 213 is installed to move the spray tube fixing part 217 up and down.

The cleaning carriage 219 is mounted on the carriage moving rail 216 and the cleaning carriage 219 can move the carriage back and forth using the rotational force of the motor 215 and the chain.

Next, let's look at the socket-side cleaning assembly.

6 is a side view showing a socket portion cleaning assembly according to a preferred embodiment of the present invention.

6, the socket assembly cleaning assembly includes a rotary fixture 261 mounted with a nozzle and a drive motor 263 for operating the rotary fixture 261, as shown in FIG. 6 do.

Since the socket portion of the cast iron pipe is formed with a groove for assembly, it is impossible to effectively remove foreign matter through the foreign matter removing assembly. Therefore, conventionally, there have been many difficulties such as the removal of foreign matter remaining in the socket portion through manual operation.

 In the present invention, a socket assembly cleaning assembly is added to solve this difficulty.

6, a socket cleaning nozzle 262 for spraying high-pressure compressed air is mounted on the rotary fixture 261, and the rotary fixture 261 is rotatable through 90 degrees through the drive motor 263 The socket of the cast iron pipe is cleaned for cleaning.

In addition, a tube support roller 264 is provided at the end of the socket to prevent the tube from being pushed toward the socket when the cast iron tube is rotated, and a rotary assembly is installed to effectively remove foreign substances inside the cast iron tube. It is possible to increase the effect of removing foreign matter from the socket portion.

A lower hood (27) is provided under the socket assembly cleaning assembly to allow the foreign matter to fall down below the socket assembly cleaning assembly. The upper hood (25) So that foreign matter can be easily collected.

Next, a heating furnace will be described.

FIG. 7 is a side view showing a heating furnace according to a preferred embodiment of the present invention, and FIG. 7A is a front view of FIG.

After the polishing and cleaning processes have been completed, the cast iron pipe is moved through a conveying conveyor to enter a heating furnace to heat the cast iron pipe.

In this heating furnace, the thermoplastic resin powder coating is heated to 160 to 380 degrees Celsius, which is a suitable temperature for melt-coating the inner surface of the cast iron tube.

The burner 310 is installed on both sides of the heating furnace 300 and the internal temperature of the heating furnace 300 is kept constant. In order to effectively heat the burner 310, the burner 310 is installed vertically and horizontally symmetrically, Allow hot air to circulate easily.

7A, the automatic gate 340 is connected to the door 344, the door 342, and the door 344. The door 344, the door 344, A power transmission shaft 342 and a power transmission motor 343 so that the rotational force of the power transmission motor 343 is transmitted to the power transmission shaft 342, The chain gear assembled to the transmission rod 342 rotates to drive the lifting body 341 connected to the door to move the door up and down.

Here, the door guide 345 prevents the door from moving when the door is moved up and down, and can detect the opening degree of the door through the position sensing sensor 346 installed on the door guide 345.

That is, it is possible to automatically set the opening height according to the diameter of the cast iron pipe introduced into the heating furnace, so that the heat loss in the heating furnace can be minimized.

Finally, let's look at the socket and outer end face coating assemblies and the powder coating assemblies.

In the present invention, as in the cleaning process, the socket assembly and the outer assembly coating assembly, which are made of grooves and curved surfaces due to the characteristics of the cast iron pipe, are difficult to uniformly coat.

First, referring to the socket portion and the outer end face coating assembly, FIG. 8 is a side view showing a socket portion and an outer end face coating assembly according to a preferred embodiment of the present invention.

As shown in FIG. 8, the socket assembly and the outer end face coating assembly serve to coat the socket portion and the outer end face portion of the cast iron pipe through the heating furnace by using the electrostatic powder coating gun, have.

A driving wheel 412 for horizontally moving the conveyance truck 413 and a cylinder 414 for regulating the height of the conveyance truck 413. The conveying truck 413 is provided with an electrostatic powder coating gun 411, ).

When the cast iron pipe heated to the proper coating temperature in the heating furnace is transferred to the painting booth through the outlet of the heating furnace, the thermoplastic resin powder coating is applied to the inner surface of the socket portion by electrostatic powder coating.

Therefore, the painted gun conveyance bogie 413 on which the electrostatic powder coating gun 411 is mounted is provided with the drive wheel 412 at the upper portion to enable the conveyance bogie 413 to be supported and moved when moving back and forth, A cylinder 414 is provided at the lower portion of the conveying carriage 413 and the power is transmitted to the conveying carriage 413 by connecting the conveying carriage 413 with the connection bracket 415.

The position of the paint gun 411 is determined as the paint gun conveyance truck 413 is moved up and down. A servomotor 422 and a rotary screw 423 are installed under the paint gun conveyance truck 413, It is possible to determine the ascending and descending speed and the ascending and descending direction through the rotating screw according to the motor rotating speed and the rotating direction.

That is, the height of the coating gun can be easily adjusted according to the shape or the diameter of the socket portion of the cast iron pipe, and the coating gun can be painted by electrostatic powder coating while moving the gun forward and backward at a predetermined speed and distance to enable more efficient and uniform thickness coating.

 9 is a side view showing a powder coating assembly according to a preferred embodiment of the present invention.

The powder coating assembly serves to coat the inner surface of the cast iron tube through a nozzle provided at the end of the coating tube. The powder coating assembly is rotated over a rotating roller of the rotating assembly 130 as shown in FIG. 9, The thermoplastic resin powder paint supplied through the coated paint tube 512 is sprayed from the end of the spray nozzle 511 and painted.

9, the powder coating assembly 510 includes a rail 540 installed horizontally, a moving carriage 520 installed on the rail 540, a height adjustment unit 520 installed on the moving carriage 520, And a nozzle 511 provided at an end of the coating pipe 512. The nozzle 511 is provided at the end of the coating pipe 512. [

In addition, since the coating tube 512 is inserted into the tube heated to a high temperature, it is preferable to cool the coating tube by circulating the cooling water in order to prevent the powder coating material inside the coating tube 512 from melting or aggregating due to heat Do.

As described above, the present invention provides a cast iron pipe inner surface coating apparatus for coating a thermoplastic resin powder coating, and the above-described embodiments are only one embodiment with reference to the drawings, so that the true scope of the present invention is not limited to Should be determined by the claims.

3: Cast iron pipe
20: transfer assembly
21: Driving motor
25: Conveyor frame
26: Chain
27: Bracket
29:
130: Rotating assembly
131: a plurality of rotating rollers
132: Up / down cylinder
140: Abrasive assembly
141: Grinding stone
142: Abrasive shaft
145: Abrasive truck
149: Rail
150: push assembly
151: idler rollers
154: Air cylinder
210: Debris removal assembly
211: Nozzle
212: air blower
213: Servo motor
214:
215: drive motor
216: rail
217:
219: cleaning car
260: Socket cleaning assembly
261: Rotary jig
262: Nozzles
263: Driving motor
300: heating furnace
410: Socket portion and outer end face coating assembly
411: Electrostatic Powder Coating Gun
412: drive wheel
413:
414: Cylinder
510: Powder Coating Assembly
511: Nozzles
512: paint tube
517:
520: Moving lane
540: rail

Claims (8)

A conveyance assembly for horizontally conveying the cast iron pipe through the conveying conveyor;
A plurality of rotating assemblies installed below the transfer assembly to rotate the cast iron tube using a plurality of rotating rollers and a lifting cylinder;
A pressing assembly for pressing an upper portion of a cast iron pipe rotated through the rotary assembly using an air cylinder and an idle roller installed at an end of the air cylinder;
An abrasive assembly for abrading an inner circumferential surface of the cast iron tube through a grindstone provided at an end of the abrading shaft mounted on the abrading bogie;
A foreign matter removing assembly for removing foreign matter in the cast iron pipe using compressed air injected through a nozzle installed at an end of the air spray pipe;
A socket assembly cleaning assembly for removing foreign matter from a cast iron tube socket portion rotated through the rotary assembly using a nozzle mounted on the rotary fixture;
A heating furnace for heating a cast iron pipe moved through the conveying conveyor;
A socket portion and an outer end face coating assembly for coating a socket portion and an outer end face portion of the cast iron pipe through the heating furnace with an electrostatic powder coating gun;
And a powder coating assembly for coating the inner surface of the cast iron tube through a nozzle provided at an end of the paint tube.
The pressing assembly includes:
And an idle roller installed at an end of the air cylinder and contacting the outer circumferential surface of the cast iron pipe while being moved up and down,
Further comprising a position sensor for sensing a position of the idler roller and a proximity sensor for checking whether the idler roller is normally operated or not.
The method according to claim 1,
The transfer assembly,
A chain installed in the conveyor frame; a bracket installed in the chain so that the cast iron pipe is seated; and a driving motor for driving the chain.
The method according to claim 1,
The foreign matter removing assembly includes:
A height adjuster installed at the cleaner, an air sprayer installed at the height adjuster, and a nozzle installed at an end of the air sprayer, Wherein the inner surface of the cast iron tube is coated with a thermoplastic resin powder.
The method according to claim 1,
The socket portion cleaning assembly includes:
A rotary jig equipped with a nozzle, and a drive motor for operating the rotary jig. 2. The cast iron pipe inner coating device for coating a thermoplastic resin powder coating according to claim 1,
The method according to claim 1,
Wherein the socket portion and the outer end face coating assembly comprise:
And a servomotor for adjusting the height of the transporting carriage, characterized by comprising: a transporting carriage provided with a static electricity powder coating gun; a robot cylinder for horizontally moving the transporting carriage; a driving wheel; and a servomotor for adjusting the height of the transporting carriage. .
The method according to claim 1,
The powder coating assembly comprises:
A height adjuster provided at the moving carriage, a coating pipe installed at the height adjusting portion, and a nozzle installed at an end of the coating pipe. The inner surface coating device for cast iron pipes for coating thermoplastic resin powder.
A thermoplastic resin powder coating material according to any one of claims 1 to 7, wherein the inner surface of the cast iron tube coating apparatus is coated with a thermoplastic resin powder coating prepared by binding a metal ion (Na + or Zn +) to ethylene methacrylic acid (EMAA) And outer surface is coated with thermoplastic resin powder paint coated with asphalt paint or modified alkyd paint.

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