JPH06246219A - Drying oven for coating - Google Patents

Abstract

PURPOSE:To avoid excess baking caused by longer passing time in an drying oven than ordinary time and not to generate inferior coating generated by readhesion of an org. solvent component in the exhaust gas caused by partly stopping of the heating zone formed in the drying oven even when the conveyer speed is made slower. CONSTITUTION:In a tunnel-type drying oven for coating wherein the coating film of a specimen to be coated carried by means of a conveyer 2 is dried by heating, a plurality of oven unit U1-U4 each provided with heating apparatus 3 and 4 and a unit 7 for connection being placed removably between oven units arranged with a const. distance in the front and rear direction of the oven and connecting both front and rear oven units are formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel type drying oven for coating, which heats and dries a coating film on a substrate to be coated.

[0002]

2. Description of the Related Art For example, in the case of drying a coating film of an electro-deposited automobile body, the finished automobile body is conveyed by a conveyor while being passed through a tunnel type drying oven for a predetermined time to be dried. I am trying to let you. In this case, the drying oven for painting is designed to have a length that can secure the required drying time when the automobile body is conveyed at a predetermined speed, but the conveyance speed of the automobile body depends on the production amount per unit time. Since it is decided, if the production amount changes after the design, the conveying speed also changes, and the furnace length must be changed accordingly.

For example, when the production amount is small, the conveyor speed is lowered, and therefore, when the car body is conveyed at the slow speed, the passing time of the drying furnace is longer than usual, resulting in coating failure due to excessive baking. Therefore, it is necessary to shorten the furnace length. For this reason, conventionally, when a plurality of heating zones are provided in the coating drying furnace and the transportation speed of the automobile body is reduced, for example, by stopping the heating device in the heating zone on the rear stage side, The length is substantially shortened to prevent excessive seizure.

[0004]

However, even if the distance of the heating zone is shortened, the exhaust gas is cooled in the resting heating zone on the downstream side, and the organic solvent components contained in the exhaust gas adhere to the automobile body. However, the paint will be defective. That is,
Although the coating failure due to excessive baking has been solved, this time a new problem arises in which the organic solvent component contained in the exhaust gas adheres to cause coating failure. Therefore, the present invention is
Even if the conveyor speed is slowed down, it is a technical issue to dry the coating film without causing coating failure due to excessive baking and coating failure caused by adhesion of organic solvent components contained in exhaust gas. .

[0005]

In order to solve this problem, the present invention provides a tunnel type coating drying oven for heating and drying the coating film of a coating material conveyed by a conveyor, in which heating devices are individually provided. Consists of a plurality of equipped furnace body units, and a connecting unit that is detachably interposed between the furnace body units arranged at regular intervals in the front-rear direction of the furnace to connect the front and rear furnace body units. It is characterized by being done.

[0006]

According to the present invention, the total length of the furnace when all the furnace units are connected is set so that the required drying time can be obtained when the object to be coated is conveyed at a speed corresponding to the maximum production amount. When the transfer speed is reduced, for example, without using the furnace body unit on the rear stage side, if the connecting unit that connects the furnace body units on the front stage side and the rear stage side is removed, the furnace body unit on the rear stage side is removed. Since it is completely separated from the furnace unit on the front stage side, the furnace length can be shortened according to the transport speed, and at the same time, even if exhaust gas leaks, it will flow out from the outlet to the furnace unit on the rear stage side. Hardly penetrates, so there is no paint failure. Also, if an air curtain unit is provided at the outlet instead of the connecting unit, it is not necessary to install an air curtain forming device in each furnace body unit, and leakage of organic solvent components etc. from the furnace body unit in use can be prevented. It is possible to reduce the equipment cost while surely preventing it.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on the embodiments shown in the drawings. FIG. 1 is a schematic explanatory view showing an example configuration of the present invention, FIG. 2 is a perspective view showing a main part thereof, and FIG. 3 is a schematic perspective view showing another embodiment.

In the figure, reference numeral 1 denotes a tunnel type drying oven for coating, which heats and dries the coating film of an object to be coated such as an automobile body conveyed by a conveyor 2, in which the furnace units U _{1 to} U ₄ are furnaces. Of the furnace body unit U ₁ at the front stage is provided with an indirect heating device 3 using dark infrared rays, and three furnace body units U _{2 at} the rear stage U ₂ , U ₃ ,
Direct heating devices ₄ , ₄ , ₄ for convection of hot air are individually arranged in U ₄ . Further, the air curtain forming device 5 is installed at the inlet of the furnace body unit U _{1 at} the frontmost stage and the outlet of the furnace body unit U _{4 at} the last stage, and the ceiling of the inlet of the furnace body unit U ₁ and the furnace body units U ₂ , U _An exhaust hood 6 for sucking the exhaust gas leaking from each of the furnace body units U _{1 to} U ₄ is arranged at the exit ceiling of U ₃ and U ₄ .

Reference numeral 7 denotes a connecting unit which is removably interposed between the furnace body units U _{1 to} U ₄ and connects the front and rear furnace body units to each other without a gap, and faces each other from both left and right sides of the conveyor 2. Two halves 7 so that they can be attached
Each half body 7R, 7L is divided into R and 7L, and an expandable and contractable bellows 8 is formed at one end side thereof so that it can be easily attached between the furnace body units U _{1 to} U ₄ .

The reference numeral 9 designates, for example, when the latter-stage furnace body units U ₃ and U ₄ are not used, the former-stage furnace body unit U ₂ is replaced with the connecting unit 7 for connecting the furnace body units U ₂ and U ₃ together. A unit for an air curtain arranged at an outlet, which is equipped with an air curtain forming device 10, and whose overall length is formed shorter than the interval between the furnace body units U _{1 to} U ₄ , for example, the outlet of the furnace body unit U ₂ . Is not connected to the inlet of the furnace body unit U ₃ , the unused furnace body units U ₃ and U ₄ can be completely separated from the furnace body unit U ₂ .

The above is an example of the configuration of the present invention, and the operation thereof will be described below. For example, when the article to be coated is conveyed at a speed corresponding to the maximum production amount, the furnace unit U ₁ ~
All of U ₄ are connected by the connecting unit 7, and the air curtain forming devices 5 and 5 at the inlet of the furnace body unit U ₁ and the outlet of the last furnace body unit U ₄ are operated to form an air curtain.

Then, after the coated object having been coated is indirectly heated by the furnace body unit U ₁ , the furnace body units U ₂ , U _{3 are} heated.
And by directly heating with U ₄ , it is possible to appropriately heat and dry over a required time. At this time, since the exhaust gas does not leak from between the furnace body units U _{1 to} U ₄ , the intake fan (not shown) of the exhaust hood 6 between the furnace body units U _{2 to} U ₄ is stopped.

The production amount is 3/4, 1 of the maximum production amount.
When it becomes / 2, the conveying speed of the coated object is also reduced to 3/4 and 1/2. In this case, even if the time of indirect heating is lengthened, it does not affect the coating so much, but if the total heating time including the time of direct heating becomes too long, yellowing due to excessive heating occurs, Furnace body units U ₃ , U ₄
The machine is paused according to the conveyor speed to adjust the time for direct heating.

For example, when the transport speed is halved,
Quiesces subsequent furnace unit U ₃ and U ₄ by using only the furnace member unit U1 and U _2. Then, first, the connecting unit 7 arranged between the furnace body units U ₂ and U ₃ is removed, the air curtain unit 9 is attached to the outlet of the furnace body unit U ₂ , and the intake fan (not shown) is operated. Then, the exhaust gas is sucked from the exhaust hood 6 arranged at the outlet.

At this time, the furnace body units U ₃ and U ₄ are stopped, but since the transfer speed of the object to be coated is slow, the furnace body unit U ₁ is indirectly heated and then the furnace body unit U ₂ is directly heated. By doing so, it is possible to appropriately heat and dry over a required time. At this time, the furnace unit U ₂
Since the air curtain is formed by the air curtain unit 9 at the outlet of the, the exhaust gas does not leak and it is not necessary to equip each of the furnace body units U ₂ and U _{3 with} an air curtain forming device. The equipment cost can be reduced.

Further, the unused furnace unit U ₃ ,
Since U ₄ is completely separated from the used furnace body units U ₁ and U ₂ , even if exhaust gas leaks from its outlet,
Furnace unit U _3, without entering little to U ₄ is not used, therefore, the organic solvent component nor produce poor paint adhering to the surface of the object to be coated. In particular,
In this example, since the exhaust gas is sucked from the exhaust hood 6, there is no possibility that the exhaust gas will enter the furnace body units U ₃ and U ₄ .

In the description of the embodiment, the furnace unit U
_{Although the type in which 1} is indirectly heated and the furnace units U _{2 to} U ₄ are directly heated has been described, the arrangement, the number of units, and the like can be set arbitrarily. For example, all units are indirectly heated or It may be of a direct heating type. Also, only the case where the latter furnace body unit is not used was explained, but when there are multiple units of the indirect heating method, or when all units are the indirect heating method or the direct heating method, the latter furnace body unit is used. Alternatively, the furnace unit at the previous stage may be stopped. In this case, the air curtain unit 9 is arranged at the inlet of the furnace unit at the latter stage, and
The exhaust hood 6 formed on the ceiling surface may suck in the exhaust gas leaking from the inlet.

FIG. 3 shows another embodiment. In this embodiment, the furnace body is
20 is a plurality of heating zones Z₁~ Z_FourPartitioned into the front
Heating zone Z₁Indirect heating device 21 by dark infrared
The second and subsequent heating zones Z provided₂~ Z_FourHot air
When the direct heating devices 22 for convection are individually provided,
At the inlet and outlet of the furnace body 20, the heating zone Z₂And Z ₃
The air curtain forming device 23 is provided on the exit side of the
It

Further, the side surface of the furnace body 20 is provided in each heating zone Z.
Insulation panel 24 that can be attached to and detached from the part between _{2 and} Z ₄
Is attached to, for example, the heating zones Z ₃ and Z _{4 in the} subsequent stage.
When not in use, the insulation panel 24 between the heating zones Z ₂ and Z ₃ is opened. Further, on the ceiling surface of the furnace body 20, exhaust hoods 25, 25 for sucking the exhaust gas leaking from the heating zones Z ₂ , Z ₃ when the side surfaces are opened are formed.

When the article to be coated is conveyed at a speed corresponding to the maximum production amount, by using each panel 24 in a closed state, the article to be coated is appropriately heat-dried over a required time. For example, when the production amount becomes 3/4 of the maximum production amount, the conveying speed is reduced to 3/4, the direct heating device 22 in the heating zone Z ₄ is stopped, and the time for direct heating is set. By adjusting, yellowing due to excessive heating is prevented.

At this time, the heating zones Z ₃ and Z ₄
Insulating panels 24, 24 arranged on both left and right side surfaces between
And the side surface is opened to operate the air curtain forming device 23 arranged on the outlet side of the heating zone Z ₃ and also to operate the intake fan (not shown) to exhaust the exhaust hood arranged on the ceiling surface thereof. Inhale exhaust gas from 25. Also,
By opening the heat insulation panel 24, the heating zone Z ₄
Is completely separated from the heating zones Z _{1 to} Z ₃ being used, and the exhaust gas leaking from the heating zone Z ₃ is sucked by the exhaust hood 25.
There is no danger of entering ₄ and it can be dried appropriately.

[0022]

As described above, according to the present invention, not only the substantial length of the drying furnace can be freely adjusted according to the speed of the conveyor to dry the material in an appropriate drying time. It is possible to reliably prevent the organic solvent component from adhering to the exhaust gas and improve the coating quality.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a coating drying furnace according to the present invention.

FIG. 2 is a perspective view showing a main part thereof.

FIG. 3 is a schematic perspective view showing another embodiment.

[Explanation of symbols]

1 ... paint drying furnace 2 ... conveyor 3 ... indirect heating apparatus 4 ... direct heating apparatus U ₁ ~U ₄ ... furnace unit 7 ... connecting unit 9 ... Air Curtain unit Z _{1 to} Z ₄ ... Heating zone 20 ... Furnace body 21 ... Indirect heating device 22 ... Direct heating device 24 ... Insulation panel 25 ... Exhaust hood

Claims (3)

[Claims] 1. A tunnel type drying oven for coating, which heats and dries a coating film of a substrate conveyed by a conveyor (2), comprising a plurality of furnace units (e.g., heating devices (3, 4)). U _{1 to} U ₄ ) and a connecting unit (7) which is detachably interposed between the furnace body units arranged at regular intervals in the front-rear direction of the furnace and connects the front and rear furnace body units. A drying oven for painting, which is composed of 2. A tunnel-type drying oven for coating, which heats and dries a coating film on an object to be coated, which is conveyed by a conveyor (2), and comprises a plurality of furnace units (equipped with heating devices (3, 4)). U _{1 to} U ₄ ) and a connecting unit (7) which is detachably interposed between the furnace body units arranged at a constant interval in the front-rear direction of the furnace and connects the front and rear furnace body units.
And a connecting unit (7) that is arranged at the outlet of the front-side furnace body unit instead of the connecting unit (7) when the rear-side furnace body unit is not used. A drying oven for coating, characterized in that it is constituted by an air curtain unit (9) arranged at the entrance of the furnace unit on the latter stage side instead of 7). 3. A furnace body (20), which is individually equipped with a heating device (21, 22) and is located between heating zones arranged in front and rear, is opened so that the side surface of the furnace body (20) can be closed. A drying oven for painting, characterized in that an exhaust hood (25) for sucking the exhaust gas leaking from the heating zone is provided on the ceiling surface.