JPH031094Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a direct heating type paint drying oven suitable for baking and curing paint films formed on the surfaces of objects to be painted such as automobile bodies. It is something.

[Conventional technology]

BACKGROUND ART Conventionally, a direct heating type paint drying oven as shown in FIG. 4 has been used to bake and harden a paint film formed on the surface of an object to be painted, such as an automobile body.

In FIG. 4, 50 is a paint drying oven,
The coating drying furnace 50 has a furnace body 51 formed in the shape of a tunnel, one of which is an inlet 51a, and the other is an outlet 51b. Further, an outlet 51 is provided from the inlet 51a of the furnace body 51 to the center of the bottom of the furnace body 51.
A conveyor 52 is laid in the direction b, and a plurality of dogs 54 are arranged at intervals on the upper surface of the conveyor 52 to be hooked to a trolley 53 on which an object W on which a coating film has been formed is placed and transported. There are several. Rails 55 are provided on both sides of this conveyor 52.
is provided on which a trolley 53 is placed and guided.

Further, a circulation duct 56 formed in a U-shape is disposed on the outside of the upper part of the furnace body 51, one end of which is open to the inlet 51a side of the furnace body 51, and the other end of the circulation duct 56 is open to the inlet 51a side of the furnace body 51. It is open to the exit 51b side.
Furthermore, a heating burner 57 is provided on the outer upstream side of the circulation duct 56, and its nozzle 57a is located within the circulation duct 56.

The burner 57 also includes a fuel supply source (not shown).
A supply pipe 58 leading to the combustion air is connected to a supply duct 59 that takes in combustion air.
A blower 60 is provided in the middle of the tube 9, and a filter 61 is provided at the tip.

Further, a filter 62 and a circulation fan 63 are sequentially provided on the downstream side of the burner 57 of the circulation duct 56, and an exhaust duct 65, which is provided with a damper 64 in the middle thereof, is connected to the downstream side thereof.

When baking and curing the coating film formed on the workpiece W on the trolley 53 transported by the conveyor 52, a predetermined amount of fuel is supplied to the burner 57 from the supply pipe 58 and the supply duct 59. Air is supplied to cause combustion, and the obtained heated air is supplied into the furnace body 51 from the circulation duct 56 by the circulation fan 63, and the air in the furnace body 51 is supplied into the circulation duct 56 to generate heated air. Mix with the furnace body 5 again.
1 and maintain it at a predetermined temperature.
In this state, the workpiece W on the cart 53 is moved to the furnace body 51.
It is designed to bake and harden the paint film by passing it through the interior.

[Problem that the invention attempts to solve]

However, in such a paint drying furnace, when baking and curing the paint film formed on the object W to be painted, the low-molecular resin and solvent in the paint film evaporate and cause damage inside the furnace body 51 and It circulates in the circulation duct 56. Therefore, the low-molecular resin and solvent come into contact with the flame of the burner 57 during circulation and are oxidized to form oxides. Since this oxide has the property of being easily absorbed into the paint film formed on the object to be painted, it not only discolors the paint film but also adheres to the wall surface of the furnace body 51 and the circulation duct 56. There is a problem in that the particles scatter and adhere to the paint film, causing coating defects such as spots.

Therefore, this invention was made to solve the above-mentioned problems, and by providing an air injection means in the circulation duct to form an air curtain surrounding the flame of the burner, it is possible to reduce the molecular weight. The purpose of this method is to prevent the resin and solvent used in the process from coming into contact with the flame of the burner, thereby preventing the formation of oxides, and also preventing the occurrence of coating defects such as discoloration and spots.

[Means for solving problems]

That is, in the direct heating type paint drying oven according to this invention, a circulation duct with both ends open inside the furnace body is provided outside the furnace body with both ends open, and a heating burner is installed in the middle of this circulation duct. It is a direct heating type paint drying furnace in which the heated air obtained by the heating burner is circulated through the furnace body and the circulation duct to bake and harden the paint film of the object to be painted. Air injection means is provided to form an air curtain surrounding the flame of the heating burner.

[Effect]

In such a direct heating type paint drying oven,
When baking and curing the paint film formed on the object to be painted, heated air obtained by a heating burner is supplied and circulated into the furnace body from a circulation duct, and an air injection means is operated. Surround the burner flame with an air curtain. and,
When the inside of the furnace body is maintained at a predetermined temperature by circulating heated air, the object to be coated on which the paint film has been formed is passed through the furnace body to bake and bake the paint film.
Let it harden.

At this time, low-molecular resins and solvents in the paint film evaporate and circulate inside the furnace and circulation duct, but since an air curtain is formed around the flame of the heating burner, heated air is Low-molecular resins and solvents that circulate together are blocked and prevented from coming into contact with the burner flame, thereby preventing the formation of oxides. This also prevents the occurrence of coating defects such as discoloration and spots on the coating film formed on the object to be coated.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

Fig. 1 is a partially cutaway front view illustrating a direct heating type paint drying oven according to the present invention, Fig. 2 is a sectional view taken along the - line of Fig. 1, and Fig. 3 is a - of Fig. 2.
It is a sectional view along a line.

In FIGS. 1 and 3, reference numeral 1 denotes a paint drying furnace, and the paint drying furnace 1 has a furnace body 2 formed in the shape of a tunnel, and both ends of the furnace body 2 are open. One side is designated as entrance 2a,
The other side is designated as the exit 2b.

Further, an inlet 2a of the furnace body 2 is provided at the bottom center of the furnace body 2.
A conveyor 3 is laid toward the exit 2b, and a plurality of dogs 4 are provided at intervals on the upper surface of the conveyor 3. This dog 4 is connected to a trolley 5 on which the object W on which the paint film is formed is placed.
It is designed to be latched onto the rear of the vehicle and transported. Furthermore, conveyor 3 is provided on both sides of conveyor 3.
Rails 6 are laid with a gap between them, on which the trolley 5 is placed and guided.

Further, a circulation duct 7 formed in a U-shape is arranged on the outside of the upper part of the furnace body 1, one end of which is open to the inlet 2a side of the furnace body 2, and the other end of the circulation duct 7 of the furnace body 2. It is open to the exit 2b side. Furthermore, a heating burner 8 is provided on the outer upstream side of the circulation duct 7.
is provided, and its nozzle 8a is directed toward the circulation duct 7 side.

Further, the burner 8 is connected to a supply pipe 9 that leads to a fuel supply source (not shown) such as gas or heavy oil, and a supply duct 10 that takes in air for combustion. Blower 11
is provided, and a filter 12 is provided at the tip. When the air supply blower 11 operates, clean combustion air that has passed through the filter 12 is supplied to the burner 8, and the supply pipe 9
Fuel is supplied to the burner 8 and burned. Thereby, heated air is supplied to the circulation duct 7.

In addition, a filter 13 is installed on the downstream side of the circulation duct 7.
A circulation fan 14 and a circulation fan 14 are sequentially provided at intervals, and an exhaust duct 16 having a damper 15 disposed in the middle thereof is connected to the downstream side thereof.
When the circulation fan 14 is operated, the heated air supplied to the circulation duct 7 and the air inside the furnace body 2 are circulated within the furnace body 2 and the circulation duct 7, so that the inside of the furnace body 2 reaches a predetermined temperature. It is now being maintained.

Further, a circular pipe 17 is provided at the front of the burner 8 of the circulation duct 7 so as to surround the flame H from the burner 8. Slit-shaped injection port 1
7a is formed. And this pipe 17
is made of a metal material, ceramics, etc., and is designed to withstand the high temperature of the flame H of the burner 8.

Further, an L-shaped supply pipe 18 is connected to the top of the pipe 17 and extends upward through the circulation duct 7, and a blower 19 for air supply is connected to the top of the pipe 17.
is provided, and a filter 20 is provided at the tip. When the blower 19 operates, clean air that has passed through the filter 20 is supplied from the supply pipe 18 to the pipe 17, and is injected from the injection port 17a to form an air curtain Y so as to surround the flame H of the burner 8. is beginning to form.

The flow rate of the air curtain Y is the circulation duct 7.
The circulation fan 14 installed in the circulation duct 7
It is desirable that the flow rate be lower than the flow rate of the heated air circulating in the furnace body 2, and excess air is discharged outside the system by adjusting the opening/closing degree of the damper 15 provided in the exhaust duct 16.

In the coating drying oven 1 configured as described above, when baking and curing the coating film formed on the object W to be coated, the supply pipe 9 and the supply duct 10
A predetermined amount of fuel and air are supplied to the burner 8 for combustion, and the obtained heated air is supplied into the furnace body 2 from the circulation duct 7 by the circulation fan 14, and the air inside the furnace body 2 is circulated. It is supplied into the duct 7, mixed with heated air, and then supplied into the furnace body 2 again. Then, the heated air in the furnace body 1 and the circulation duct 7 is circulated to maintain the inside of the furnace body 1 at a predetermined temperature.

At the same time as fuel and air are supplied to the burner 8, the blower 19 is operated to supply air purified by the filter 20 from the supply pipe 18 to the pipe 17, and the air is ejected from the injection port 17a to cause the flame of the burner 8 to flow. An air curtain Y is formed around H.

In this state, the object to be painted W on which the paint film has been formed
is placed on a trolley 5 and passed through the furnace body 2 by the conveyor 3 to bake and harden the coating film.

At this time, low-molecular resin and solvent evaporate from the paint film and circulate within the furnace body 2 and circulation duct 7, but an air curtain Y is formed around the flame H of the heating burner 8. Therefore, the low-molecular resin and solvent circulating together with the circulating heated air are blocked, and contact with the flame H of the burner 8 is suppressed, thereby preventing the generation of oxides.
This also prevents the occurrence of coating defects such as discoloration and spots on the coating film formed on the object W to be coated.

[Effect of idea]

As explained above, in the direct heating type paint drying oven according to the present invention, since the circulation duct is provided with an air injection means that forms an air curtain surrounding the burner flame, low molecular weight Since the resin and solvent do not come into contact with the flame of the burner, it is possible to prevent the formation of oxides that would adversely affect the paint film.

In addition, the direct heating type paint drying oven of the present invention has the effect of preventing discoloration of the paint film and the occurrence of paint defects such as spots by preventing the formation of oxides. .

In addition, in the direct heating type paint drying furnace of the present invention, a large amount of high-temperature air is exhausted from the furnace body to the outside of the system in order to reduce the amount of oxides that cause discoloration and spots on the paint film. However, this can be reduced, which has the effect of significantly reducing exhaust heat loss.

In addition, the direct heating type paint drying oven according to the present invention has the effect of reducing the cost of baking and curing the paint film by significantly reducing the loss of exhaust heat. be.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view illustrating a direct heating type paint drying oven according to the present invention. FIG. 2 is an enlarged sectional view taken along the - line in FIG. 1. Third
The figure is a sectional view taken along the - line in FIG. 2. FIG. 4 is a partially cutaway front view illustrating a conventional direct heating type paint drying oven. 1... Paint drying oven, 2... Furnace body, 7... Circulation duct, 8... Burner, 9... Supply pipe, 10... Supply duct, 13... Filter, 14... Circulation fan, 17... Pipe, 19... Blower, 20...
filter.

Claims (1)

[Scope of utility model registration request] A circulation duct with both ends open inside the furnace body is provided outside the furnace body with both ends open, and a heating burner is installed in the middle of this circulation duct, and the heated air obtained by this heating burner is transferred to the furnace. A direct heating type paint drying oven that bakes and hardens the paint film of the object to be coated by circulating it inside the body and through a circulation duct, wherein an air curtain is formed in the circulation duct so as to surround the flame of a heating burner. A direct heating type paint drying oven characterized by being equipped with an air injection means.