JPH081019Y2 - Radiant drying oven for automobile bodies - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Field of Industrial Application The present invention relates to a drying furnace for drying a coating film by heating an automobile body that has been spray-painted by an automatic coating machine. In particular, the present invention relates to a radiation type drying oven for drying a coating film by dark infrared rays emitted from a radiation panel heated with hot air.

(2) Conventional technology The coating of the automobile body, which has been spray-painted, is dried by heating it to a high temperature of about 150 ° C in a drying furnace. In the step of drying the coating film, a hot air drying furnace is used in which hot air composed of combustion gas is supplied by a fan into a furnace in which an automobile body mounted on a conveyor moves at a low speed.

However, since the uncured wet coating immediately after the spray coating is completed is in a state where dust is easily attached,
When the hot air drying furnace is used, dust contained in the combustion gas may adhere to the coating film to deteriorate the coating quality. For this reason, a radiation-type drying furnace that cures a coating film wet by dark infrared rays emitted from a heated panel to a state where dust is unlikely to adhere is provided in the preceding stage of the hot air drying furnace (for example, , Japanese Utility Model Publication No. 62-140981). In this way, the coating film can be temporarily cured in the radiation type drying furnace where dust is not likely to adhere, and then the coating film can be completely dried in the hot air drying furnace in the subsequent stage.

FIG. 5 shows the above-mentioned conventional radiant drying oven, in which a truck 02 for moving an automobile body B is mounted on the hearth of a drying oven 01 having a rectangular cross section extending in the direction perpendicular to the plane of the drawing. A conveyor 03 is provided. Three hot air circulation ducts 04, 05, 06 are provided on the left and right oven walls of the drying oven 01, and the inside of the hot air circulation ducts 04, 05, 06 is dried by the drying oven 01.
The hot air supplied from the hot air supply device 07 provided at the upper part of the circulates. The surface of the hot air circulation ducts 04, 05, 06 facing the automobile body B is constituted by flat plate-shaped radiation panels 04a, 05a, 06a, and the radiation panel 04 heated by the hot air is used.
The coating film of the automobile body B is dried by the dark infrared rays emitted from the surface of a, 05a, 06a.

(3) Problems to be Solved by the Invention However, in the above conventional radiant drying oven, since a flat radiant panel irradiates dark infrared rays to an automobile body having a three-dimensional shape composed of curved surfaces. The intensity of dark infrared rays received by each part of the automobile body becomes non-uniform, and the temperature rising speed of each part of the automobile body is not uniform, that is, uneven heating easily occurs. For this reason, the temperature of the drying path is set with reference to the part that is the farthest from the body and has the lowest rate of temperature rise in the body. Therefore, the heat generation capacity from the radiation panel must be set larger than necessary as a whole. However, energy is wasted, and the body part where the temperature rise rate is high tends to overbak on the contrary. Therefore, a heat shield plate (Fig. 1) for preventing overbaking is specially installed between the radiation panel and the radiation panel. However, there is a problem that the structure of the furnace becomes complicated accordingly.

The present invention has been made in view of the above circumstances, and in a radiant drying oven that heats an automobile body with dark infrared rays emitted from a radiation panel, the intensity of the dark infrared rays received by the automobile body is made uniform in each part of the body. It is an object of the present invention to solve the above problems all at once by reducing uneven heating.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a radiation panel constituting a wall surface of a hot air circulation duct arranged along a furnace wall of a drying furnace. In a radiant drying oven of an automobile body, which is opposed to the surface of an automobile body conveyed in a drying oven and heats the automobile body with dark infrared rays emitted from the surface of the radiant panel, It is characterized in that it is composed of a curved plate curved in an arc shape so as to follow the outer shape, and the radiation panel surrounds the surface of the automobile body passing through the drying path at a substantially constant distance.

(2) Operation According to the features of the present invention described above, when hot air is supplied to the hot air circulation duct, the temperature of the radiant panel rises and dark infrared rays are radiated toward the automobile body in the furnace, and the automobile The body is dried by radiant heat of dark infrared. At this time, since the radiation panel is composed of a curved plate curved in an arc shape so as to follow the outer shape of the automobile body, and the distance between the automobile body and each portion of the radiation panel is kept substantially constant, each portion of the automobile body is Since the temperature rising speed is substantially constant, each part of the automobile body can be heated substantially uniformly.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show a radiant drying oven according to an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a drying oven including the radiant drying oven, and FIG. 2 is a radiant drying. It is a cross-sectional view of a furnace.

As shown in FIGS. 1 and 2, the drying furnace for drying the automobile body B on which spray coating has been completed includes a front air seal chamber 1, a radiation type drying furnace 2, a hot air drying furnace 3, which are connected in series. And the rear air seal chamber 4. The radiant drying furnace 2 has hot air circulation ducts 24 and 25,
A hot air supply device 5 for supplying high temperature air to the hot air circulation ducts 24, 25 and a hot air circulation device 6 for agitating and circulating the air in the furnace are provided.

Hot air supply device 5 provided at the upper part of the radiant drying oven 2
Includes a combustion chamber 7 that burns a fuel gas such as city gas or natural gas to generate high-temperature combustion gas, and a fan 8 that supplies the combustion gas as hot air into the radiant drying furnace 2. Then, when the automobile body B whose coating film immediately after spray coating is in the Wet state is carried into the radiant drying oven 2 by the conveyor 9, the temperature in the oven is heated to about 150 ° C. and the coating film of the automobile body B is produced. Curing is performed. The hot air drying oven 3 connected to the rear part of the radiation type drying oven 2 has a filter chamber 1
0, combustion chamber 11, and fan 12 for hot air supply device 13
The coating film is completely dried by maintaining the inside of the furnace at a constant temperature of about 150 ° C. In the front and rear air seal chambers 1 and 4, the air that has passed through the filter 14 is supplied by the fan 15 to form an air curtain, and the inside of the radiant drying furnace 2 and the hot air drying furnace 3 is shut off from the outside air.

As is clear from FIG. 2, the radiant drying oven 2 is provided with oven walls 16a to 16d each having a rectangular cross section and made of a heat insulating material. The conveyor 9 laid on the lower furnace wall 16a that constitutes the hearth is provided with a pair of rails 18 provided on the upper portions of the pillars 17, and a carriage 20 having wheels 19 is movably supported on the upper portion thereof. There is. A dog 22 guided by a guide member 21 provided on the lower furnace wall 16a is fixed to the lower surface of the carriage 20.
By connecting an endless chain 23 connected to a drive source (not shown) to the vehicle 22, the carriage 20 moves in the furnace in a direction perpendicular to the plane of the drawing with the vehicle body B placed thereon.

Upper and lower hot air circulation ducts 24 and 25 extending in a direction perpendicular to the plane of the drawing are provided on the side furnace walls 16b and 16c, respectively. The fan 8 provided on the upper surface of the upper furnace wall 16d is connected to the upstream end of the lower hot air circulation duct 24 via the hot air duct 26, and the hot air flowing in one direction in the lower hot air circulation duct 24 is It flows in the opposite direction in the upper hot air circulation duct 25 connected to its downstream end and is circulated through the hot air duct 26. Also, some hot air equivalent to the amount of outside air taken in is the exhaust duct.
It is discharged from the furnace from 27. Upper and lower hot air circulation ducts 24, 25
The surface facing the automobile body B is composed of radiation panels 28 and 29 which are curved plates formed by bending a metal plate in an arc shape. The curved shapes of the radiation panels 28, 29 are formed in an arcuate shape along the outer shape of the automobile body B so as to surround the surface of the automobile body B to be heated with a substantially constant distance. .

On the other hand, the hot air circulation device 6 includes a hot air supply duct 30 and a hot air return air duct 31 at the lower and upper parts of the hot air circulation ducts 24 and 25.
It has. The hot air in the furnace is supplied to the hot air supply duct 30 through the space 32 formed along the side furnace walls 16b and 16c, and the hot air passes through the inside of the furnace from the opening 30a of the hot air supply duct 30. The air is returned to the hot air return air duct 31 through the opening 31a, and is circulated through the fan 34 and the filter 35 provided in the circulation duct 33.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

First, the spray-painted automobile body B placed on the carriage 20 of the conveyor 9 is carried into the radiant drying oven 2 through the air seal chamber 1. Next, the fuel gas is burned in the combustion chamber 7 provided in the upper portion of the radiant drying furnace 2, and the generated high temperature combustion gas is supplied from the hot air duct 26 to the lower hot air circulation duct 24 by the fan 8. The combustion gas passing through the lower hot air circulation duct 24 further passes through the upper hot air circulation duct 25 and is circulated by the hot air duct 26. At that time, the radiant panels 28, 29 forming the side walls of both hot air circulation ducts 24, 25 are heated, and the automobile body B is heated by the radiant heat of dark infrared rays radiated from the surfaces thereof to dry and cure the coating film. Be seen. At this time, since the radiation panels 28 and 29 are curved in an arc shape so as to surround the automobile body B, the automobile body B is
Are uniformly heated.

In parallel with the drying of the coating film by the radiant heat of the dark infrared rays,
The hot air in the furnace is supplied to the hot air supply duct 30 via the circulation duct 33 by the fan 34. Opening 30 of hot air supply duct 30
The hot air blown into the furnace from a is sucked into the hot air return air duct 31 through the opening 31a and circulates. The circulation of the hot air heats the interior of the automobile body B which is not directly hit by the dark infrared rays emitted from the radiation panels 28 and 29, and
The convection of air in the furnace is promoted to make the temperature uniform, and the heating effect can be further improved.

When the temperature in the furnace and the temperature of the automobile body B rise to about 150 ° C. and the coating film hardens as described above, the automobile body B is conveyed by the conveyor 9 to the hot air drying oven 3 in the next step.

FIG. 3 and FIG. 4 are graphs showing the state of temperature rise when the conventional radiant drying oven and the radiant drying oven according to the present invention are used, respectively, and the solid line indicates the temperature of the atmosphere in the oven and the alternate long and short dash line. Indicates the temperature of the door of the automobile body, the two-dot chain line indicates the temperature of the roof, and the broken line indicates the temperature of the bonnet.

As is clear from the figure, the conventional radiant drying oven (3rd
(Fig.) Not only is there a considerable difference in the rate of temperature rise in each part of the car body, but it also takes about 20% to reach the target temperature of 150 ° C.
Need a minute. On the other hand, in the radiant drying oven of the present invention (Fig. 4), not only the temperature rising rate of each part of the car body is almost the same, but the car body temperature reaches 150 ° C in about 10 minutes which is about half of the conventional one. , A very remarkable effect is recognized.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various small designs can be made without departing from the present invention described in the scope of claims for utility model registration. It is possible to make changes.

For example, the left and right hot air circulation ducts 24, 25 may be one or three or more, instead of being divided into two as in the embodiment. Further, the hot air supplied into the hot air circulation ducts 24, 25 is not limited to the combustion gas, and high-pressure steam can be used.

C. Effect of the Invention As described above, according to the present invention, a radiation panel that is heated by hot air supplied to a hot air circulation duct and radiates dark infrared rays is a curved plate curved along an outer shape of an automobile body in an arc shape. Since the radiant panel surrounds the surface of the automobile body passing through the drying path at a substantially constant distance, the distance between the radiant panel and each part of the automobile body is kept substantially constant and the automobile body is made uniform. And it can be heated efficiently, which not only makes it possible to improve the coating quality by keeping the temperature rising speed of each part of the car body almost constant, but also raises the heat generation capacity from the radiation panel more than necessary. Or even without installing a heat shield plate to prevent overbaking between the panel and the car body, uneven heating of the car body is effectively avoided, saving energy and drying Shortening of, it can also contribute to the structural simplification of the furnace.

[Brief description of drawings]

1 and 2 show a radiant drying oven according to an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a drying oven including the radiant drying oven, and FIG. 2 is a radiant drying. FIG. 3 is a graph showing a temperature rising state in a conventional radiation type drying furnace, FIG. 4 is a graph showing a temperature rising state in a radiation type drying furnace of the present invention, and FIG. FIG. 3 is a cross-sectional view of the radiation type drying furnace of FIG. B: Automotive body, 2 ... Drying oven, 16b, 16c ... Furnace wall, 24, 25 ... Hot air circulation duct, 28, 29 ... Radiant panel

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Kazuhiro Miyazaki 2373 Mizono-cho, Suzuka-shi, Mie (56) References Actually open 62-140981 (JP, U) Actually open 61-44068 (JP, U) Special public 51-13095 (JP, B2) JP-B 51-33842 (JP, B2)

Claims (1)

[Scope of utility model registration request] 1. A radiation panel (28, 29) constituting a wall surface of a hot air circulation duct (24, 25) arranged along a furnace wall (16b, 16c) of the drying furnace (2) is provided with the drying furnace (2). ) Radiation-type drying of an automobile body, in which the inside of the automobile body (B) is conveyed to face the inside thereof and the automobile body (B) is heated by dark infrared rays emitted from the surface of the radiation panel (28, 29). In the furnace, the radiation panel (28, 29) is composed of a curved plate curved in an arc shape so as to follow the outer shape of the automobile body (B), and the surface of the automobile body (B) passing through the drying path (2). A radiant drying oven for an automobile body, characterized in that the radiant panel (28, 29) is surrounded by a substantially constant distance.