KR101028405B1 - Manufacturing method of multi-layered coated steel pipe - Google Patents

Abstract

The present invention relates to a coated steel pipe manufacturing apparatus for coating an outer circumferential surface of a steel pipe, comprising: a support for supporting a steel pipe to coat an outer circumferential surface and an inner circumferential surface of the steel pipe; A first spray device for spraying the primer on the outer circumferential surface of the steel pipe at a thickness of 20 microns to 300 microns; A second spray device for spraying the polyurea on the outer circumferential surface of the primer in a thickness of 500 microns to 5,000 microns; And a first bogie spraying at least one of a primer and a polyurea on the inner circumferential surface of the steel pipe and being movable in the longitudinal direction of the steel pipe. The apparatus for manufacturing a multi-layered polyurethane multi- According to the present invention, there is an effect that the pretreatment work and the coating work for coating the tube can be performed simultaneously on the inner surface and the outer surface. Thus, both the inner and outer surfaces are simultaneously processed, and the two-layer coating of the primer layer and the polyurea layer is also performed at the same time, so that the working time is reduced and the production amount is maximized. Further, by forming the primer layer and the polyurea layer in two layers on the outer and inner surfaces of the steel pipe, the corrosion resistance of the steel pipe can be prevented for a long time because of excellent weather resistance, corrosion resistance and corrosion resistance. Further, even if the polyurea layer is damaged, since there is a primer layer, corrosion of the steel pipe can be more easily prevented.

Description

TECHNICAL FIELD [0001] The present invention relates to a polyurea coating method,

The present invention relates to an apparatus and a method for manufacturing a multi-layered polyurethane multi-layered coated steel pipe, and more particularly to a multi-layered multi-layered steel pipe manufacturing apparatus and method for manufacturing a multi- And a polyurea layer simultaneously. The present invention also relates to a manufacturing method and a manufacturing method of a multi-layered coated steel pipe.

Generally, a cast iron pipe, a steel pipe, or the like is used for a pipe used for a conveyance pipe for conveying fluid or gas. These steel tubes are coated on the outer surface or the inner surface by various coating methods to extend the service life and prevent corrosion.

Of the conventional steel pipe coating methods, the T-die extrusion coating method requires a large investment cost in coating the outer surface of the steel pipe, and a large amount of personnel is used, so that the investment payback period is long and a large space, The price increases, and there is a disadvantage that much of the necessity of subsidiary materials is increased.

In the case of coating a monolayer of polyurea even in the case of polyurea coating, corrosion of the surface of the coated surface may occur when the polyurea coating is damaged, and when the polyurea is exposed to the external environment, yellowing of the coating film occurs, There is a problem that this occurs.

In addition, when the outer surface of the steel pipe is coated with three layers of powder, there is also a problem that the equipment cost is increased.

In order to more reliably prevent such corrosion of the steel pipe, coating is applied to the inner surface as well as the outer surface of the steel pipe. However, in the coated coated steel pipe, corroding of the peeled portion occurs at the peeling of the steel pipe coating due to deterioration of the adhesiveness over time, and when the adhesion of the inner surface of the steel pipe is deteriorated, corrosion occurs on the iron surface of the releasing portion, There is a problem that the iron component dissolves when the fluid is transported, such as the supply, and the water quality may be deteriorated.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for simultaneously and simultaneously forming a primer layer and a polyurea layer on the outer and inner surfaces of a non- The present invention provides a method for manufacturing a multi-layered polyurethane coated steel pipe and a manufacturing method thereof.

According to an aspect of the present invention, there is provided a coated steel pipe manufacturing apparatus for coating an outer circumferential surface of a steel pipe, comprising: a support for supporting a steel pipe to coat an outer circumferential surface and an inner circumferential surface of the steel pipe; A first spray device for spraying the primer on the outer circumferential surface of the steel pipe at a thickness of 20 microns to 300 microns; A second spray device for spraying the polyurea on the outer circumferential surface of the primer to a thickness of 500 to 5,000 microns; And a first bogie spraying at least one of a primer and a polyurea on the inner circumferential surface of the steel pipe and being movable in the longitudinal direction of the steel pipe.

At this time, the supporting portion includes: a loading base on which the steel pipe is loaded; A cylinder key cylinder integrally provided with a stacking pedestal on one side of the stacking cradle and driven up and down; And a turning roller provided at a lower portion of the cylinder key cylinder to rotate the steel pipe.

In addition, a guide roller is further provided on one side of the steel pipe, which is provided with the turning roller, to prevent the steel pipe from being separated from the steel pipe at a predetermined distance along the longitudinal extension of the steel pipe.

A second bogie is further provided, wherein the first bogie injects the primer and the second bogie injects the polyurea.

Further, the second truck is provided in the same or opposite position as the first truck with respect to the steel pipe.

The first truck and the second truck each include a body portion moving along the longitudinal direction of the steel pipe; A pump provided at one side of the body to provide a composition for coating the inner circumference of the steel pipe; A wheel provided at a lower side of the body portion; A motor for providing a driving force for driving the first and second bogies and regulating the driving speeds of the first and second bogies; A boom stand protruding from one side of the body portion and inserted into the inside of the steel pipe; And a spray nozzle provided at one side of the center of the boom frame for spraying a primer or polyurea in one direction.

Further, a boom stand is provided on the boom stand to prevent swaying of the boom stand.

Further, a guide rail for providing a path of movement of the first spray device and the second spray device is further provided.

Further, the polyurea-coated steel pipe manufacturing apparatus comprises: a conveyor for conveying a steel pipe; And a pretreatment device provided at one end of the conveyor for pretreatment for cleaning and coating the outer and inner circumferential surfaces of the steel pipe.

Further, a plurality of drive rollers for conveying the steel pipe are further provided on one side of the conveyor.

The pretreatment apparatus further includes a steel pipe drying device for removing moisture from the steel pipe to remove rust on the outer circumferential surface or the inner circumferential surface of the steel pipe; A shroud for removing a scale formed on an outer surface or an inner surface of a steel pipe; And an air device for removing dust from the steel pipe; And the like.

The pretreatment apparatus further comprises a steel pipe cutting device for cutting the steel pipe to be conveyed to a predetermined length.

Further, the primer is any one of 40% to 100% of solid epoxy, zinc primer, solvent-type urethane and water-soluble urethane.

As another category, it is an object of the present invention to provide a method of conveying a steel pipe, A pretreatment device for pretreating the outer circumferential surface and the inner circumferential surface of the steel pipe to coat the outer circumferential surface and the inner circumferential surface of the steel pipe; And a third step of simultaneously coating an outer circumferential surface and an inner circumferential surface of the steel pipe, and the third step comprises: a third step of rotating the steel pipe by the support part; The first spray device moves along the longitudinal direction of the steel pipe and while the primer is sprayed to the outer circumferential surface of the rotating steel pipe at a thickness of 20 microns to 300 microns while the first car runs in the inner direction of the rotating steel pipe, 3-2; And the second spray device moves and the second bogie runs in the same direction as the first bogie while spraying the polyurea on the outer peripheral surface of the primer sprayed on the outer peripheral surface of the steel pipe at a thickness of 500 microns to 5,000 microns, And a third step (3) of spraying the polyurea on the inner circumferential surface of the applied primer.

In this case, before the step 3-2 is performed, the boom zone of the first car or the float of the second car enters the inside of the steel pipe and waits.

Further, while the boom band entering into the inside of the steel pipe leaves the steel pipe and while the primer or polyurea is sprayed, another boom stand enters the inside of the steel pipe and injects the polyurea or the primer.

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According to the present invention, there is an effect that the pretreatment work and the coating work for coating the tube can be performed simultaneously on the inner surface and the outer surface. In this manner, all the operations of the inner surface and the outer surface are performed at the same time, so that the working time is reduced, the investment cost of the equipment is low, and the production amount is maximized. Further, since the two-layer coating of the primer layer and the polyurea layer is simultaneously performed, the working time is further reduced and the production amount is maximized.

Further, by forming the primer layer and the polyurea layer in two layers on the outer and inner surfaces of the steel pipe, the corrosion resistance of the steel pipe can be prevented for a long time because of excellent weather resistance, corrosion resistance and corrosion resistance. Further, even if the polyurea layer is damaged, since there is a primer layer, corrosion of the steel pipe can be more easily prevented.

In addition, the use of a non-inventive polyurea provides an excellent weather resistance to the external environment, thereby preventing appearance color change of the coating film even when exposed to the outside.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description, serve to further the understanding of the technical idea of the invention, And shall not be interpreted.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view schematically showing the overall configuration of a multi-layered polyurethane multi-layer coated steel pipe manufacturing apparatus according to an embodiment of the present invention;
Figure 2 is a side view of the support according to the invention,
Fig. 3 is a view showing the use of the cylinder key of the support portion according to the present invention,
4 is a side view of an outer circumferential surface and an inner circumferential surface coating apparatus according to the present invention,
5 is a detailed view of an outer circumferential surface and an inner circumferential surface coating apparatus according to the present invention,
FIG. 6 is a flowchart showing a method for manufacturing a multi-layered polyurethane multi-layer coated steel pipe according to the present invention,
7 is a cross-sectional view of a multi-layer coated steel pipe produced by the manufacturing apparatus or the manufacturing method according to the present invention.

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

<Configuration of Multi-Layer Coated Steel Pipe Manufacturing Apparatus>

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view schematically showing the overall configuration of a multi-layered polyurethane multi-layer coated steel pipe manufacturing apparatus according to an embodiment of the present invention. As shown in FIG. 1, an unflammable polyurea multilayer coated steel pipe manufacturing apparatus 10 according to the present invention includes a conveyor 400, a pretreatment device, a support 100, a first spray device 210, A first carriage 220, a first carriage 310, and a second carriage 320.

The conveyor 400 according to the present invention is a device for conveying a steel pipe 1000 to be introduced throughout the unfavorable polyurea multilayer-coated steel pipe manufacturing apparatus 10. At one side of the conveyor 400, a driving roller 410 is provided to provide a rotational force for conveying the steel pipe 1000. At this time, the driving roller 410 can adjust the rotation angle as needed.

(Configuration of the preprocessing apparatus)

The pretreatment apparatus according to the present invention is provided at one side of a conveyor 400 into which a steel pipe 1000 is inserted to perform an operation to clean the outer circumferential surface and the inner circumferential surface of the inserted steel pipe 1000 and smooth the coating. The pretreatment apparatus 500 includes at least one of a steel pipe drying apparatus 510, a shortening unit 520, an air unit 530, and a steel pipe cutting apparatus 550.

The steel pipe drying apparatus (510) according to the present invention is an apparatus for removing the moisture of a charged steel pipe (1000) using a gas type or an electric type. The steel pipe drying apparatus 510 removes moisture from the steel pipe 1000 by heating the surface of the steel pipe 1000 to a temperature of 30 to 80 ° C by using gas or electricity.

The shorting unit 520 according to the present invention is a device for removing a scale such as an oxide layer formed on the surface of a steel pipe 1000. The shot operation is performed by projecting the soft material through the impeller rotating on the outer circumferential surface and the inner circumferential surface of the steel pipe 1000 to remove the scale. Such a configuration of the shot machine 520 includes a cabinet, a projection device, a soft material circulation device, a product transfer device, and a dust collecting device. In more detail, the cabinet is designed to transfer the doors for loading and unloading to and from the rectangular room up and down. When the door is inserted into the room for rust removal of the steel pipe 1000, the loading door is opened. When the door is seated on the rotary roller conveyor The loading door is seated in the lower part. And the exit door is opened when the rust removal of the outer circumferential surface and the inner circumferential surface of the steel pipe 1000 is completed. The impeller for removing rust on the inner circumferential surface and the outer circumferential surface of the steel pipe 1000 is installed at the end of the boom bar. A conveyor capable of rotating the steel pipe 1000 and carrying the short ball is installed on the boom bar, The circular impeller is rotated by centrifugal force. At this time, the device for providing centrifugal force rotates at a rotational speed of 2,000 to 3,600 RPM, and rotational force can be supplied using rotation by a motor and a hydraulic pump. The most preferred rotational speed is 2,450 RPM. In addition, an impeller may be installed on the outer circumferential surface of the steel pipe 1000 to remove external rust while the pipe advances.

The air device 530 according to the present invention is a device for removing dust and the like generated while removing the scale formed on the surface of the steel pipe 1000 in the short device 520. This air device 530 uses a steam washer or air-brining to remove dust, oil and moisture. Here, the steam washing machine is a device for spraying high-temperature, high-pressure steam onto the steel pipe 1000 to remove dust or the like from the surface of the steel pipe.

The steel pipe cutting apparatus 550 according to the present invention is an apparatus for cutting a steel pipe 1000 to a predetermined length in consideration of a working mode, a work space, a length of a finished coating pipe, and the like. The steel pipe cutting apparatus 550 may be omitted if the steel pipe 1000 is provided in a state where it is cut to a predetermined length at the time of initial introduction.

(Composition of coating apparatus)

FIG. 2 is a side view of a support according to the present invention, FIG. 3 is a view showing the use of a cylinder key car of a support according to the present invention, FIG. 4 is a side view of an outer circumferential surface and an inner circumferential surface coating apparatus according to the present invention, And the inner circumferential surface coating apparatus according to the present invention. 2 to 5, a coating apparatus according to the present invention includes a support 100 for supporting a steel pipe 1000, a first spray device 210 for coating an outer circumferential surface of the steel pipe 1000, A sprayer 220, a first bogie 310 and a second bogie 320 for coating the inner circumferential surface of the steel pipe 1000.

2 and 3, the supporting part 100 according to the present invention comprises a stacking cradle 110, a cylinder key cylinder 120, and a turning roller 130.

The loading pedestal 110 according to the present invention is a device for loading and conveying a steel pipe 1000 cut to a predetermined length for coating.

As shown in FIGS. 2 and 3, the cylinder key car 120 according to the present invention is provided at one side of the stacking support 110 and is capable of adjusting the height of the cylinder at a predetermined interval using a cylinder. When the steel pipe 1000 is rotated to coat the steel pipe 1000 conveyed from the stacking pedestal 110, the cylinder key car 120 can be rotated at a lowered height thereof. When the steel pipe 1000 is rotated, Thereby transferring the steel pipe 1000 to the conveying path.

3, the turning roller 130 according to the present invention is disposed at a lower portion of the cylinder key cylinder 120 and contacts the outer circumferential surface of the cylinder 1000 when the cylinder key cylinder 120 is lowered, ) To rotate. Here, a guide roller 140 may be further provided on one side of the turning roller 130 to prevent the steel pipe 1000 from being separated from the steel pipe 1000 at a predetermined distance along the longitudinal extension of the pipe.

The first spray device 210 according to the present invention is an apparatus for forming an outer primer layer 1100 by spraying a primer onto the outer circumferential surface of a steel pipe 1000 through an injector as shown in FIGS. Here, it is preferable to use any one of 40 to 100% of a solid epoxy, a zinc-based primer, a solvent-type urethane and a water-soluble urethane. The first spray coating apparatus can adjust the thickness of the outer primer layer 1100 by controlling the jetting discharge pressure. At this time, a primer layer is coated on the outer circumferential surface of the steel pipe 1000 to a thickness of 20 microns to 300 microns. When the thickness of the outer primer layer 1100 is less than 20 microns, the outer primer layer 1100 may be peeled off or the coating may not be partially formed in the subsequent process. When the outer primer layer 1100 is thicker than 300 microns, And the manufacturing cost may increase. 4 and 5, the first spray device 210 can be moved left and right along the longitudinal direction of the steel pipe 1000 along the guide rail 230, And further includes a vertical adjustment device 240 for adjusting the jetting height to adjust the jetting position.

The second spray device 220 according to the present invention has the same configuration as the first spray device 210 described above. The second spray device 220 forms the outer polyurea layer 1300 by spraying polyurea on the outer peripheral surface of the outer surface primer layer 1100 formed on the outer peripheral surface of the steel pipe 1000 by the first spray device 210 . At this time, the polyurea injected from the second spray device 220 uses a non-inventive polyurea. The outer surface of the outer primer layer 1100 is coated with the outer polyurea layer 1300 to a thickness of 500 to 5,000 microns. When the outer polyurea layer 1300 is less than 500 microns, the corrosion resistance, the antifouling performance, the water resistance and the like may be reduced. If the outer polyurea layer 1300 is more than 5,000 microns, the overall thickness of the steel pipe 1000 becomes thick, A problem may arise. The second spray device 220 may be installed at one side of the guide rail 230 of the first spray device 210, preferably in the forward direction of the first spray device 210, As shown in FIG.

The first carriage 310 according to the present invention is an apparatus for forming an inner surface primer layer 1200 by spraying a primer on the inner circumferential surface of a steel pipe 1000. At this time, the inner surface primer layer 1200 is coated to a thickness of 20 microns to 300 microns.

The second carriage 320 according to the present invention is an apparatus for forming the inner polyurea layer 1400 by spraying polyurea on the inner peripheral surface of the inner surface primer layer 1200 coated on the inner peripheral surface of the steel pipe 1000. At this time, the polyurea uses a non-compliant polyurea. The second bogie 320 is disposed in the same or opposite position as the first bogie 310 with respect to the steel pipe 1000. At this point, the inner polyurea layer 1400 is coated to a thickness of 500 microns to 5,000 microns.

The first bogie 310 and the second bogie 320 according to the present invention generally include body portions 311 and 321, pumps 312 and 322, wheels 313 and 323, a motor (not shown) , 324, and injection nozzles 315, 325.

The body portions 311 and 321 according to the present invention have a flat plate shape or a hexahedron shape with one side opened, and provide a space in which the pumps 312 and 322 can be placed.

The pump 312 and 322 according to the present invention are provided on one side of the upper part of the body parts 311 and 321 to provide a spraying force for mounting and spraying a composition such as a primer or a polyurea for coating on the inner circumferential surface of the steel pipe 1000 . These pumps 312 and 322 are preferably airless spray pumps or dedicated spray pumps.

The wheels 313 and 323 according to the present invention are provided on one lower side of the body portions 311 and 321 so that the first truck 310 and the second truck 320 can move along the longitudinal direction of the steel pipe 1000 .

The motor according to the present invention provides a driving force for driving the first truck 310 and the second truck 320 and adjusts the driving speed of the first truck 310 and the second truck 320. [

The boom stands 314 and 324 according to the present invention are provided to protrude to one side of the body parts 311 and 321 to provide a route of the composition provided by the pumps 312 and 322. The length of the floats 314 and 324 can be adjusted according to the length of the steel pipe 1000 and the height can be adjusted according to the thickness of the steel pipe 1000.

The injection nozzles 315 and 325 according to the present invention are provided on one side of the center of the boom stands 314 and 324 or one end of the boom stands 314 and 324 to spray a liquid primer or polyurea in one direction. The injection nozzle 315 of the first carriage 310 and the injection nozzle 325 of the second carriage 320 may inject the composition in the same direction and may be sprayed in different directions depending on the usage. The injection nozzles 315 of the first bogie 310 and the injection nozzles 325 of the second bogie 320 are set at different positions so that the injection nozzles 315 of the first bogie 310, It is preferable that the injection nozzles 325 of the bogie 320 intersect with each other.

The first truck 310 and the second truck 320 having the above-described construction are inserted into the steel pipe 1000 and move in the same direction from the one end of the steel pipe 1000 to the other end of the steel pipe 1000, do. That is, any one of the boom rods 314 and 324 of the first truck 310 and the second truck 320 is inserted into the other end of the steel pipe 1000 in advance so that the first truck 310 and the second truck 320, The first bogie 310 first injects the primer and the second bogie 320 injects the polyurea along the injection nozzle 315 of the first bogie 310 at approximately the same time.

A boom bar support portion 330 is further provided between the steel pipe 1000 and the first and second trucks 310 and 320 to prevent the boom bars 314 and 324 from sagging so that the boom bars 314 and 324 And keeps the movement path of the boom rods 314 and 324 constant.

(Variation of Bogie)

Although the coating apparatus composed of the two bogies 310 and 320 of the first and second bogies 310 and 320 has been described in the above description, 310 may be provided. At this time, the overall shape of the first truck 310 is similar to that of the first truck 310 and the second truck 320 described above.

In this case, pumps 312 and 322 for providing primers and polyureas are provided at one side of the body 311 of the first truck 310, respectively, and a boom block 314 connected to the pumps 312 and 322 , 324, and injection nozzles 315, 325. The length of the boom stands 314 and 324 is longer than that of the boom stand 324 connected to the pump 322 providing the polyurea so that the primer layer 314 is connected to the pump 312 providing the primer, After the first formation, a polyurea layer is formed on the inner peripheral surface of the primer layer.

<Manufacturing Method of Multi-Layer Coated Steel Pipe>

6 is a flowchart sequentially illustrating a method of manufacturing a non-inventive polyurethane multi-layer coated steel pipe according to the present invention. As shown in FIG. 6, the steel pipe 1000 is transferred to the coating steel pipe manufacturing apparatus 10 (S100). At this time, the conveying means such as the conveyor 400 for conveying the steel pipe 1000 adjusts the width thereof according to the thickness of the steel pipe 1000 and adjusts the rotation speed of the steel pipe 1000 to be conveyed. The thickness of the steel pipe 1000 to be introduced may vary from 15 mm to 4,000 mm according to the manner of use of the coating pipe.

Next, in step S200, the outer circumferential surface and the inner circumferential surface of the steel pipe 1000 are pre-treated by using the pretreatment apparatus 500 to smoothly apply the coating agent to the steel pipe 1000 to be introduced. The preprocessing step (S200) comprises the following steps.

The surface of the steel pipe 1000 is heated to 30 ° C to 80 ° C by using the steel pipe drying apparatus 510 to remove the rust on the outer and inner circumferential surfaces of the steel pipe 1000 to remove moisture from the steel pipe 1000.

Next, the scales such as the oxide layer formed on the outer circumferential surface and the inner circumferential surface of the steel pipe 1000 are removed by using the shorting unit 520.

Next, the air device 530 is used to remove the scale and remove the generated dust. At this time, dust, oil and moisture are removed by using a steam cleaner or airbrushing.

Next, the steel pipe 1000 to be conveyed by using the steel pipe cutting apparatus 550 is cut in accordance with the use mode.

Next, the outer circumferential surface and the inner circumferential surface of the steel pipe 1000 are simultaneously coated (S300). At this time, the simultaneous coating process (S300) of the outer circumferential surface and the inner circumferential surface includes the following steps.

The steel pipe 1000 conveyed by the conveyor 400 is seated on the support 100 and rotated by the turning roller 130 (S310).

Coating of the outer circumferential surface and the inner circumferential surface of the steel pipe 1000 is performed at the same time. For convenience of explanation, the coating step of the outer circumferential surface will be described first and the coating step of the inner circumferential surface will be described below. It is to be noted that the above description is merely for convenience of explanation, and it should not be understood that the coating on the outer circumferential surface and the inner circumferential surface are coated at different times.

Next, either the boom stand 314 of the first truck 310 or the boom stand 324 of the second truck 320 enters the inside of the steel pipe 1000 and waits (S315). For example, the first truck 310 and the second truck 320 are disposed at positions facing each other with respect to the steel pipe 1000. 5, the boom stand 324 of the second truck 320 is inserted into the steel pipe 1000 to advance to the end of the steel pipe 1000 where the first truck 310 is located, do. This process can be omitted if the first truck 310 and the second truck 320 are located in the same direction with respect to the steel pipe 1000 or the first truck 310 alone.

The first spray device 210 provided on the guide rail 230 spaced a predetermined distance from the steel pipe 1000 and disposed along the longitudinal direction of the steel pipe 1000 moves along the guide rail 230 and moves along the steel pipe 1000 And the primer is sprayed on the outer circumferential surface of the rotating steel pipe 1000 to form the outer primer layer 1100 (S320). At this time, the outer primer layer 1100 has a thickness of 20 microns to 300 microns.

The second spray device 220 provided on the guide rail 230 moves along the movement path of the first spray device 210 to spray the polyurea on the outer peripheral surface of the outer primer layer 1100, A layer 1300 is formed (S330). At this time, the outer polyurea layer 1300 has a thickness of 500 microns to 5,000 microns. The second spray device 220 does not wait until the first spray device 210 has moved from one end to the other end of the steel pipe 1000 and the polyurea agent Lt; RTI ID = 0.0 &gt; 210 &lt; / RTI &gt; Since the first spray device 210 and the second spray device 220 are sprayed almost simultaneously, the working time is shortened and the productivity is improved.

Next, at the same time as the first spray device 210 injects the primer, the primer is sprayed on the first carriage 310 to form the inner surface primer layer 1200 on the inner circumferential surface of the steel pipe 1000 (S320). At this time, the inner primer layer 1200 has a thickness of 20 microns to 300 microns.

The second bogie 320 moves along the movement path of the first bogie 310 to spray the polyurea on the inner circumferential surface of the inner primer layer 1200 to form the inner polyurea layer 1400 (S330) . At this time, the inner polyurea layer 1400 has a thickness of 500 microns to 5,000 microns.

Hereinafter, the inner circumferential surface coating process will be described more clearly. 5, the float 324 of the second bogie 320 is inserted into the steel pipe 1000 and waits at the other end of the steel pipe 1000 facing the second bogie. The float 314 of the first truck 310 is injected into the interior of the steel pipe 1000 and injects the primer. Next, when the primer layer is formed in a predetermined length, when the second bogie 320 moves in the same direction as the first bogie 310, the bogie base 324 of the second bogie 320 evacuates and the polyurea To form a polyurea layer.

The outer circumferential surface coating step and the inner circumferential surface coating step described above are performed at the same time, as shown in Fig. After the first sprayer 210 and the first bogie 310 finish spraying the primer, the second sprayer 220 and the second bogie 320 move and do not spray the polyurea, The second spray device 220 and the second bogie 320 are driven by the first spray device 210 and the first bogie 310 before the first sprayer 210 and the first bogie 310 spray the primer, ) And injects the polyurea. Since the outer and inner peripheral surfaces are coated simultaneously and two coating layers are formed almost simultaneously, the coating time can be shortened and the coating layer can be stably formed as shown in FIG.

< No defense Polyurea  Construction of multi-layer coated steel pipe>

7 is a cross-sectional view of a multi-layer coated steel pipe produced by the manufacturing apparatus or the manufacturing method according to the present invention. The unflammable polyurea multilayer-coated steel pipe according to the present invention is manufactured by the manufacturing apparatus 10 or the manufacturing method described above.

7, the outer surface primer layer 1100 and the outer surface polyurea layer 1300 are sequentially formed on the outer circumferential surface of the steel pipe 1000 and the inner surface of the inner circumferential surface of the steel pipe 1000 An inner surface primer layer 1200 and an outer polyurea layer 1300 are sequentially formed.

As described above, those skilled in the art will understand that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

10: Coated steel pipe manufacturing equipment
100: Support
110: Loading stand
120: cylinder cylinder
130: Turning roller
140: guide roller
210: first spray device
220: second spray device
230: guide rail
240: Vertical adjustment device
310: 1st truck
320:
311, 321:
312, 322: airless pump
313, 323: wheels
314, 324:
315, 325: injection nozzle
330: Boom bar support
400: Conveyor
410: drive roller
500: Pretreatment device
510: Steel pipe dryer
520: Shot machine
530: Air Device
550: Steel pipe cutting device
1000: Steel pipe
1100: outer primer layer
1200: inner primer layer
1300: outer polyurea layer
1400: inner polyurea layer

Claims (17)

delete delete delete delete delete delete delete delete delete delete delete delete delete A first step S100 of conveying the steel pipe 1000 by the conveyor 400;
A second step S200 of pre-treating the outer circumferential surface and the inner circumferential surface of the steel pipe 1000 by the pretreatment apparatus 500 to coat the outer circumferential surface and the inner circumferential surface of the steel pipe 1000; And
And a third step (S300) of simultaneously coating the outer circumferential surface and the inner circumferential surface of the steel pipe 1000,
In the third step S300,
A third step (S310) of causing the supporting part 100 to rotate the steel pipe 1000;
While the first spray device 210 is spraying the primer on the outer circumferential surface of the steel pipe 1000 rotating along the longitudinal direction of the steel pipe 1000 to a thickness of 20 microns to 300 microns, (S320) of spraying a primer on the inner circumferential surface of the steel pipe 1000 while traveling in the inner direction of the rotating steel pipe 1000;
While the second sprayer 220 is moving and spraying the polyurea on the outer circumferential surface of the primer sprayed on the outer circumferential surface of the steel pipe 1000 to a thickness of 500 microns to 5,000 microns, (S330) of spraying polyurea on the inner circumferential surface of the primer sprayed on the inner circumferential surface of the steel pipe 1000 in the same direction as that of the primer 310,
The boom frame 314 of the first bogie 310 or the boom frame 324 of the second bogie 320 enters into the steel pipe 1000 and waits before the step S320 is performed Further comprising a step S315,
The boom stands 314 and 324 which enter into the inside of the steel pipe 1000 are ejected from the steel pipe 1000 while spraying the primer or polyurea while the other boom stands 324 and 314 are located inside the steel pipe 1000 Wherein the polyurea or the primer is sprayed while the polyurea is introduced into the reactor.
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