KR200180388Y1 - Apparatus for coating the steel pipe with polyethylene powder - Google Patents

Abstract

The present invention relates to a device for continuously covering the inside and outside surfaces of steel pipes, especially corrugated steel pipes using polyethylene powder. The apparatus of the present invention comprises a steel pipe heating means (10) consisting of a pair of first rollers for pinching and rotating the steel pipes and burners for heating the steel pipes, and a pair of second rollers and steel surfaces for rotating the heated steel pipes. Polyethylene inner covering means (11) comprising a polyethylene injection tube for injecting polyethylene powder to the outside of the polyethylene comprising a third roller for rotating the heated steel pipe and a polyethylene injection tube for injecting polyethylene powder on the outer surface of the steel pipe It consists of a sheathing means (12) and a conveying means (14) for raising and moving the steel pipe over the rollers. According to the present invention, the inner and outer surfaces of the steel pipe can be continuously coated.

Description

Polyethylene sheathing device for steel pipes {APPARATUS FOR COATING THE STEEL PIPE WITH POLYETHYLENE POWDER}

The present invention relates to a method of continuously coating a polystyrene film on the inside and outside surfaces of a steel pipe, in particular a corrugated steel pipe using polystyrene powder, and a coating apparatus used to coat a polyethylene film.

Steel pipes, especially corrugated steel pipes buried underground, such as sewage pipes and sewer pipes, form anticorrosive coatings on the inside and outside surfaces to prevent corrosion. As such an anticorrosive coating, an anticorrosive paint is coated or a coating is made of a thermoplastic resin. In general, large corrugated steel pipes used for wastewater pipes are coated with paint to form a coating, and the coating film is lost by the reactive components contained in the wastewater. It is covered with polyethylene film.

Since polyethylene resin is chemically stable and insoluble in solvents, polyethylene is heated and melted and coated in a molten state when steel pipes or other metal materials are coated with polyethylene resin. If the base to be coated is small or wire rod, it can be coated by a simple method of passing the base metal into the resin melt, but if the base to be coated has a length of 3 m or longer and is not flexible, for example, corrugated steel pipes for wastewater and In the case of the same large steel pipe, it is known to be very difficult to coat with polyethylene because it is impossible to pass it into the resin melt.

When coating the material to be coated on the substrate, a powder coating method for spraying powder onto the substrate surface is already known. The powder coating method is a method of forming a film on the surface of the substrate while the materials to be coated are treated and heated to melt the materials, and is mainly used when the substrate is a plate. This coating method can be carried out by simply moving the substrate or moving the heater in the case of the plate to be coated, but in the case of large steel pipes, especially corrugated steel pipe, it is difficult to coat the inner surface and difficult to move. It became. To date, no method of coating large corrugated steel pipes such as waste water pipes with polyethylene powder has been developed. In order to coat the large steel pipes with polyethylene as described above, a method of heating the steel pipes in a large heating oven and covering them with a polyethylene film has been attempted, but since the facilities for heating the large steel pipes are enormous, it is virtually impossible to install large ovens. It has been found that heating to above the melting point of polyethylene requires a large amount of thermal energy, and can only be done by batch coating and not continuous coating. Therefore, there is a need for an apparatus and method capable of continuously covering large steel pipes, especially corrugated steel pipes, with polyethylene.

It is an object of the present invention to provide a device for continuously covering large steel pipes, especially corrugated steel pipes using polyethylene powder, and a method for covering polyethylene steel pipes using the device.

The object of the present invention described above is to uniformly heat the steel pipe to a temperature above the melting point of polyethylene, in particular at a temperature of 250-300 ° C. while rotating the steel pipe using a pair of rotary rollers, and to raise and move the heated steel pipe above the roller, It is achieved by the polyethylene steel pipe coating apparatus of the present invention to spray the polyethylene powder on the inner surface and the outer surface of the steel pipe to be coated while melting the polyethylene powder.

1 is a steel pipe coating apparatus according to the present invention.

2 is a side view of the first FIG. Device;

Figure 3 is an excerpt sectional view of the main portion of the inner covering means.

4 is a partial cross-sectional view of the inner injection pipe;

5 is a partial sectional view of an external injection pipe;

6 is a partially enlarged sectional view of an external injection pipe;

<Description of the main parts of the drawings>

10 ... steel pipe heating means 11 ... underwear covering means

12 Outer sheathing means 13 Steel pipe cooling means

14 ... Measuring means for conveying steel pipes 21,22,25,26 ...

23.Heater 24 ... Axle

27 ... internal spray line 28 ... piston / cylinder unit

29.Injector 30 ... Cooling Jacket

31,34 ... Roller for rotating steel pipe 32 ... Outer injection pipe

33.Injector 35 ... Air injection pipe

36 ... Chain 40,41,42,43 ... Steel Pipe Support Plate

44. Moving plate 45, 46. Piston / cylinder unit

47 ... support plate 48 ... roller

49 ... piston / cylinder unit 50 ... rail

The present invention is a steel pipe heating means consisting of a pair of rotary rollers for supporting and rotating steel pipes and burners for heating the steel pipes, a transfer means for moving the heated steel pipes to the polyethylene coating step, and a pair of rotary rollers and steel pipes. Polyethylene steel pipe coating device of the present invention comprising a polyethylene coating means comprising a polyethylene injection pipe for spraying polyethylene powder on the surface.

In the present invention, the polyethylene coating means of the steel pipe is an inner injection means which is installed above the steel pipe and the inner coating means including a movable internal injection pipe configured to enter and exit the steel pipe by a piston / cylinder device at both ends of the steel pipe. It consists of an outer covering means comprising a. The above-described inner coating means and outer coating means are a single device for coating the inner and outer surfaces of the steel pipe at the same time by spraying polyethylene powder on the inner surface and the outer surface using the inner spray pipe and the outer spray pipe while rotating the steel pipe on a pair of rollers Rotating the steel pipe on the inner coating means for coating the inner surface of the steel pipe by spraying polystyrene powder on the inner surface of the steel pipe with the inner injection pipe while rotating the steel pipe on the pair of rollers It may be composed of an outer coating means for spraying polyethylene powder to the outer injection pipe while covering the outer surface of the steel pipe. When the inner and outer surface covering means of the steel pipe are separated, the inner surface may be first coated and the outer surface may be coated, or the outer surface may be coated and then the inner surface may be coated.

The above-described inner injection pipe has injection holes at its ends. The inner injection pipe forms a coolant jacket through which cooling water is circulated on the main wall of the injection pipe so as to prevent the polyethylene powder from being melted by the heat of the steel pipe or forms an insulating layer so that the polyethylene powder is not melted inside the injection pipe by the radiant heat of the steel pipe. It is desirable to avoid. The outer injection pipe is fixed above the steel pipe and has a plurality of injection holes suitable for the length to be covered. This outer injection pipe preferably has a hopper-type blocking plate with a long open bottom on both sides of the injection pipe in order to prevent the powder from scattering around.

The steel pipe steel roller rotating rollers constituting the above-described steel pipe heating means and steel pipe covering means may be connected by a chain gear so as to rotate at the same speed.

The steel pipe conveying means of the present invention includes a piston / cylinder device fixed to a moving plate installed forward and backward in the moving direction of the steel pipe below both end portions of the steel pipe and a steel pipe support plate fixed to the piston / cylinder device. The above-described steel pipe support plate is installed to be located under each roller, so that the steel pipes supported on each roller can be moved one step at a time. According to this structure, a coating | coating operation | movement is made continuously.

The device of the present invention may be provided with a support roller for supporting the pipe to be transferred to the heating means in front of the heating means, in which case the support roller does not need to be rotated, but the pipe conveying means is installed under the support roller to cover the work. When moving the pipe, it is good to carry the processed steel pipes supported by the rollers constituting the respective processing means simultaneously to the next step.

The apparatus of the present invention may also comprise cooling means in front of the covering means. This cooling means comprises a pair of rotary rollers and a cooling air jet tube.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 and 2 show a steel pipe covering apparatus of the present invention in which polyethylene covering means are divided into inner covering means and outer covering means. The steel pipe covering device was composed of a steel pipe heating means 10, an polyethylene covering means composed of an inner covering means 11 and an outer covering means 12, a steel pipe cooling means 13, and a steel pipe conveying means 14.

The steel pipe heating means 10 consisted of a pair of rotary rollers 21a, 21b, 22a, 22b and a heater 23 provided to be rotatable on both sides. The rotary rollers are rotated in the same direction, and when the rollers rotate, the steel pipe A supported thereon rotates. The heater 23 shown in Fig. 1 is in the form of a gas burner installed directly under the steel pipe A, but this heater may be an electric heater. The above-described bilateral rotating rollers 21a, 21b, 22a, and 22b are connected to the shaft 24, respectively. However, each pair of rotary rollers may be installed separately without using a shaft.

In Fig. 1, the polyethylene covering means is composed of an inner covering means 11 and an outer covering means 12. The inner covering means 11 is a rotary roller 25a, 25b, 26a of the same type as the rotary rollers 21a, 21b, 22a, 22b provided in the above-described heating means 10 rotatably installed on both sides. And 26b) and two sets of inner spray pipes 27a and 27b installed to be inserted into the steel pipe at both ends of the steel pipe and spraying polyethylene powder. The powder injection pipes 27a and 27b are capable of advancing back and forth into the steel pipe by the piston / cylinder devices 28a and 28b. The powder injection pipes 27a and 27b have injection holes 29 at their ends and the coolant circulates on the outer circumferential surface. It has a cooling jacket 30 to prevent the polyethylene powder from being melted by heating above the melting point in the injection pipe.

The outer sheathing means 12 is provided above the rollers for rotating the steel pipes 31a and 31b of the same type as the rollers provided in the heating means 10 and an outer injection pipe for spraying polyethylene powder onto the outer surface of the steel pipe ( 32). The polyethylene powder injection pipe 32 is fixedly installed in the longitudinal direction above the steel pipe supported on the rollers 31a and 31b, and has a plurality of injection holes 33 formed in the longitudinal direction. If necessary, a hopper-type powder scattering prevention plate for preventing powder from scattering may be formed on both sides of the aforementioned injection pipe 32.

The drying means 14 has steel pipe rotation rollers 34a and 34b of the same type as the roller of the heating means 10 and a cooling air injection pipe provided above the above-mentioned rollers. This cooling means can be made to cool with ambient air, without providing the air injection pipe 35. FIG.

Each of the steel pipe support rollers 21, 25, 31, and 34 constituting the aforementioned heating means 10, inner covering means 11, outer covering means 12 and cooling means 13 are It is connected to the chain 36 so that it can rotate at the same speed by a motor (not shown).

The steel pipe conveying means 14 of the present invention is installed below the outer end of the steel pipe outside the respective steel pipe support rollers constituting the heating means 10, the inner covering means 11, the outer covering means 12, and the cooling means 13. Steel pipe support plates 40, 41, 42, 43 are included. The above-described steel pipe support plates are fixed to the support plates 47 fixed to the piston / cylinder devices 45 and 46 installed on the moving plate 44 so that the support plates are elevated by the piston / cylinder device. The moving plate 44 described above has a plurality of rollers 48 on the bottom thereof, and is moved forward and backward on the rail 50 by the piston / cylinder device 49.

Hereinafter, a coating method using the apparatus of the present invention will be described.

The steel pipe (A) is put on the rotary rollers (21a, 21b) of the heating means 10 and heated to a temperature of 250-300 ° C by the burner (23). After the steel pipe is heated, the steel pipe is lifted up onto the rollers using the piston / cylinder device 45, 46 to move the steel pipe onto the inner covering means 11, and then the steel pipe is lowered to the rollers 21a, 21b. ) To be supported. At this time, the steel pipes processed on the inner covering means 11 and the outer covering means 12 are simultaneously moved to the next treatment step. After the steel pipe is supported by the roller of the inner covering means 11, the polyethylene powder is slowly inserted into the polyethylene powder injection pipes 27a and 27b into the piston / cylinder devices 28a and 28b while rotating the roller. When spraying, the polyethylene powder sprayed by the rotation of the steel pipe is uniformly sprayed on the entire inner circumferential wall of the rotating steel pipe and melted to form a film. Subsequently, the steel pipe having a film formed on the inner circumferential surface is moved to the outer coating means 12, and the steel pipe is rotated while spraying the powder into the polyethylene powder injection pipe 32 installed above the steel pipe. While uniformly covering the entire outer circumferential surface is melted to form a film. In this way, the inner and outer coated steel pipes are transferred to the cooling means 13 in the same manner, and then sprayed with cooling air to the air injection pipes 35 to dry to solidify the coating.

According to the present invention, the supporting plates 40, 41, 42, and 43 constituting the steel pipe conveying means 10 are the heating means 10, the inner covering means 11, and the outer covering means 12, respectively. And heating means 10, inner covering means 11, outer covering means 12, located below the respective steel pipe support rollers constituting the cooling means 13 and connected to each other to move the conveying means 14. The steel pipes treated on the cooling means 13 are processed simultaneously and moved to the next step, thereby enabling continuous processing. The steel pipes treated in this way are finished coated on the part which contacts the rotary roller and the uncoated part of the outside in the after-treatment process.

According to the present invention, since the steel pipes are simultaneously processed on the heating means 10, the inner covering means 11, the outer covering means 12 and the cooling means 13, the introduction of the steel pipes to be treated and the discharge of the treated steel pipes are made simultaneously. Since the continuous processing is possible, and the coating is performed using polyethylene powder, it is not necessary to use a large container for oiling polyethylene powder, thereby reducing the processing time and reducing the processing cost and manpower.

In particular, the present invention is advantageously used for coating large corrugated steel pipes used for waste water pipes and sewage pipes.

Claims (6)

A steel pipe heating means (10) comprising a pair of first rollers (21a) and (21b) for pinching and rotating the steel pipe and a burner for heating the steel pipe; Steel pipe including a pair of rollers (25a, 25b; 31a, 31b) for rotating the heated steel pipe and the inner spray pipe (27a), (27b) and the outer spray pipe 32 for spraying polyethylene powder on the inner surface of the steel pipe A polyethylene continuous sheathing device of steel pipes comprising inner and outer covering means (11,12) of steel pipes covering inner and outer surfaces and conveying means (14) for raising and moving the steel pipes over rollers. 2. Device according to claim 1, characterized in that the outer injection pipe (32) is installed on the inner coating means (11) so that the inner and outer surfaces of the steel pipe are simultaneously covered. 2. The device according to claim 1, wherein the inner injection pipes (27a) (27b) are installed to advance back and forth into the steel pipe heated by the piston / cylinder device and have a cooling jacket (30) on the circumferential wall. The steel pipe support plate (40) of claim 1, wherein the steel pipe conveying means (14) is provided below the steel pipe outer end outside the respective steel pipe supporting rollers constituting the heating means (10) and the inner and outer covering means (11, 12). And 42) and 43, wherein the steel pipe support plates are fixed to the piston / cylinder devices 45 and 46 fixed to the movable plate 44 installed to move forward and backward to move up and down. Characterized in that the device. 2. Device according to claim 1, characterized in that the individual steel pipe support rollers constituting the heating means (10), the inner covering means (11) and the outer covering means (12) are connected by a chain gear. 2. Device according to claim 1, characterized in that it comprises cooling means consisting of a support roller and a cooling air injection tube behind the outer sheathing means (12).