JP2953485B2 - Powder coating equipment for pipe inner surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for coating powder on the inner surface of a pipe for applying powder coating to the inner surface of a pipe such as a cast iron pipe.

[0002]

2. Description of the Related Art When a cast iron tube is manufactured by a centrifugal casting method or the like, it has been proposed to apply a powder coating for protecting the inner surface thereof. At the time of this powder coating, a tube heated to a predetermined temperature is rotatably supported around a horizontal axis, a spray nozzle is inserted into the inside, and powder paint is ejected from the spray nozzle toward the inner surface of the tube. I have.

[0003]

However, in the case of spraying the powder coating material from the spray nozzle, the nozzle inserted into the tube is moved from one end of the tube to the other end thereof. The entire length of this tube must be painted. For this reason, it takes time to paint,
There is a problem that the temperature of the tube must be appropriately controlled during the coating from the one end to the other end, and the control is difficult.

Accordingly, an object of the present invention is to solve such a problem and shorten the coating time and to easily control the temperature of the pipe.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a powder coating material which can be inserted into a horizontal pipe, and which is horizontally rotated inside the pipe rotating around an axis. A trough capable of dropping the powder coating toward the inner surface of the pipe by rotating about an axis, and an air nozzle capable of ejecting air over the length direction of the trough to diffuse the powder coating falling from the trough. It has the structure which has.

[0006]

In such a configuration, when the inner surface of the tube is powder-coated, the tube heated to a predetermined temperature is supported horizontally and rotated around an axis while the trough containing the powder coating is removed from the tube. Insert inside. If the trough is gradually rotated around the horizontal axis and turned over while ejecting air from the air nozzle, the powder paint falls from the trough and the air from the nozzle capable of ejecting air over the length of the trough. While being diffused by air, it adheres uniformly to the inner surface over the entire length and circumference of the tube.

[0007]

In FIG. 4, reference numeral 10 denotes a ductile cast iron tube which is horizontally supported by rollers 12 and is rotatable about a horizontal axis. The pipe 10 has a receiving port 14 at one end and an insertion port 16 at the other end, and a pipe body 18 is formed between the receiving port 14 and the insertion port 16.

4 to 6, reference numeral 20 denotes a coating apparatus according to the present invention, which has a carriage 22 which can reciprocate in the pipe axis direction toward one end of the pipe 10. On trolley 22, this trolley
A trough 24 is provided which protrudes in a cantilever manner in the tube axis direction from 22. The trough 24 is inserted into the inside of the pipe 10 by the movement of the bogie 22 and is positioned away from the bottom of the pipe 10. The trough 24 is formed to have a length corresponding to the length of the tube 10. Further, a trough reversing drive device 26 is provided on the carriage 22. The inversion drive device 26 has a trough
The proximal end of the trough 24 is connected, and the trough 24 can be inverted by gradually rotating the trough 24 about a horizontal axis, that is, a tube axis.

The trough 24 is formed in a trough shape as shown in FIG. 5, and can accommodate a predetermined amount of the powder coating material 28 therein. On the side of the trough 24, an air pipe 30 is arranged over the length direction of the trough 24, and by forming a large number of air ejection ports 32 in the air pipe 30,
An air nozzle 34 is configured. The air outlet 32 is shown in FIG.
May be arranged in a straight line as shown in FIG. 7, or may be arranged in a plurality of rows in a staggered manner as shown in FIG. Alternatively, the air outlet 32 may be formed in a single slit shape as shown in FIG. As shown in FIG. 5, the air ejection port 32 is arranged at a predetermined distance 38 from the opening end face 36 of the trough 24 toward the bottom of the trough 24.

In such a configuration, when powder coating is performed on the inner surface of the tube 10, the tube 10 heated to a predetermined temperature after the inside of the inner surface is rubbed is supported by rollers 12 in the horizontal direction. Then, a predetermined amount of powder coating material 28 is supplied into the trough 24 over the entire length, and the truck 22 is run to insert the trough 24 into the tube 10.

Then, while the tube 10 is rotated by the roller 12 and the air is jetted from the air nozzle 34, the trough 24 is gradually inverted by the inversion driving device 26. The situation at this time is shown in FIGS.

FIG. 1 shows a state at the time when the trough 24 inserted into the tube 10 starts to be inverted. From this state, when the trough 24 gradually rotates and reaches a certain angle as shown in FIG.
Start falling into 10. The falling powder coating material 28 uniformly reaches the inner surface of the tube 10 in a state of being diffused by air from the nozzle 34 in the same manner as ordinary spray coating, and is fused to the inner surface by the heat of the tube 10.

FIG. 3 shows a state in which the drop of the powder coating material 28 is about to be completed. Upon completion of this drop, the port 14 of the pipe 10 and the trunk
Powder coating is applied over the entire length and the entire circumference of the inner peripheral surface including the entirety of the insert 18 and the insertion opening 20. Thereafter, the trough 24 is pulled out of the pipe 10 by running the carriage 22, and the coated pipe 10 is carried out.

As described above, since powder coating can be simultaneously performed over the entire length of the tube 10, the coating can be completed in a short time and the temperature of the tube 10 can be easily controlled. An appropriate amount of the powder coating 28 is supplied into the trough 24 according to the diameter of the tube 10 and the like. For example, when the tube 10 has a small diameter, the amount is small, and the amount of the powder coating
It only begins to fall when 24 rotates.

A relatively high speed rotation of the tube 10 enables uniform coating, but a low speed has the advantage that the temperature of the tube 10 does not easily decrease. Also, if the rotation speed is gradually increased after the start of dropping of the powder coating material 28 so that the speed is high when the falling of the powder coating material 28 is completed, it is possible to paint well.

The air blown out of the air nozzle 34 needs to have an appropriate pressure and flow rate, and the higher the air pressure, the better the atomization of the powder coating material 28. Also, the higher the air flow rate, the better the diffusion of the powder coating material 28. However, if the air is too strong, the powder inside the tube 10 will be scattered, causing adverse effects such as a decrease in yield and a tendency for the film thickness to become uneven in the tube axis direction. The air outlets 32 are arranged in a plurality of rows in a zigzag manner as shown in FIG. 7, rather than being arranged in a row as shown in FIG. In addition, rather than having a configuration having a plurality of such ejection ports 32, as shown in FIG. 8, by forming a single slit-shaped ejection port 32 continuous in the length direction of the air pipe 30, Further uniformity can be achieved.

As described above, the air outlet 32 is
A constant distance 38 from the open end face 36 of the
This configuration has the advantage that the jetted air is diffused before reaching the position of the opening end face 36 and the powder coating 28 is evenly scattered. is there. If the air pipe 30, that is, the jet port 32, is too close to the open end face 36, the jetted air is not sufficiently diffused,
A problem arises in that the powder coating material 28 falls directly onto the inner surface of the pipe 10 without being diffused between the adjacent ejection ports 32.

[0018]

As described above, according to the present invention, a trough capable of dropping powder paint toward the inner surface of a pipe by rotating about a horizontal axis in a horizontal pipe rotating about an axis, An air nozzle capable of ejecting air over the length of the trough in order to diffuse the powder paint falling from the trough is provided, so that powder coating can be performed uniformly and simultaneously over the entire length of the pipe, It is possible to efficiently coat the inner surface of the tube in a short time and easily control the temperature of the tube.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of a powder coating apparatus for an inner surface of a pipe according to an embodiment of the present invention, showing a state at the time when a trough starts reversing.

FIG. 2 is a cross-sectional view of a main part similar to FIG. 1, showing a state where a powder coating material is falling.

FIG. 3 is a cross-sectional view of a main part similar to FIG. 1, showing a state in which the dropping of the powder paint is about to be completed.

FIG. 4 is an overall front view of the powder coating apparatus.

FIG. 5 is a transverse sectional view of a main part in FIG. 5;

FIG. 6 is a plan view of a main part in FIG. 5;

FIG. 7 is a diagram showing another example of the air pipe.

FIG. 8 is a diagram showing still another example of the air pipe.

[Explanation of symbols]

 10 Tube 24 Trough 26 Reversing drive 28 Powder paint 34 Air nozzle

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-123617 (JP, A) JP-A-59-146076 (JP, U) JP-A-58-14659 (JP, U) 21303 (JP, B2) Jikken 36-1488 (JP, Y1) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05C 7/00-7/08 B05C 19/00, 19/04 B05D 7/22

Claims (1)

(57) [Claims] The powder coating material can be inserted into a pipe in a horizontal direction in a state in which the powder coating material is contained, and the powder coating material can be rotated around a horizontal axis inside the pipe rotating about an axis, so that the powder coating material can be inserted into the pipe. The trough that can be dropped toward the surface and the length of the trough to spread the powder paint falling from this trough
An air nozzle capable of ejecting air over the entire surface of the tube.