JPH0415331Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a drying furnace for coating, and in particular, a furnace body that is open at both ends and formed in a tunnel shape, such as a flat furnace or a mountain furnace. This invention relates to an improvement in a coating drying oven for baking and drying a coating film by continuously passing the coating object through it.

[Technical background]

Tunnel-shaped coating drying ovens with open ends of the oven body are suitable for continuous mass production using conveyors, and are therefore used as baking drying ovens for, for example, automobile painting.

By the way, in such a drying oven, the coating film is heated and dried at a high temperature of about 120 to 200 degrees Celsius, so
Organic solvents such as thinner and toluene contained in paint and amine compounds such as hardeners for paint resins evaporate, producing harmful gases. In particular, during baking drying performed after electrodeposition coating, a large amount of smoky noxious gas containing greasy substances that emit a strong odor is generated from the coating film formed by the cationic or anionic paint.

When such harmful gases are generated and the air inside the furnace is contaminated, drying efficiency deteriorates and the paint film turns yellow, causing negative effects such as yellowing, and if the concentration of contamination increases further, there is a risk of fire or explosion. arise.

Furthermore, since both ends of the furnace body of this type of drying furnace are open, there is a problem in that harmful gases generated within the furnace body flow out of the furnace together with the heated air.

[Prior art and its problems]

Conventionally, the contaminated air inside the furnace is discharged to the outside of the furnace through an exhaust duct equipped with an exhaust fan and fed to a deodorizing and purifying device, and new clean heated air is introduced into the furnace. In addition to preventing yellowing of the paint film and deterioration of drying efficiency, an air curtain is formed at the entrance and exit of the furnace body to prevent harmful gases generated inside the furnace from flowing out of the furnace together with the heated air. .

However, since the entrance and exit of the furnace body is very wide open, cold outside air enters the furnace from below, and an amount of heated air corresponding to the amount of outside air that enters flows out of the furnace along with harmful gases. This phenomenon occurs, especially when transporting objects to be coated such as automobile bodies, the intrusion of outside air and the outflow of heated air at the entrance and exit of the furnace body are significant, and the amount of outflow of air inside the furnace containing harmful gases increases significantly. It had the disadvantage of

[Purpose of invention]

Therefore, the present invention aims to suck in the cold outside air that is trying to enter the furnace from below the inlet or outlet of the furnace and forcibly exhaust it, while also effectively forcing the heated air that is trying to flow out of the furnace from above. The purpose is to prevent the air inside the furnace containing harmful gases from flowing out of the furnace.

[Structure of the idea]

In order to achieve this object, the present invention provides a coating drying furnace in which a coating material is heated and dried by passing it continuously through a tunnel-shaped furnace body with both ends open, and an outlet portion and/or Alternatively, an air suction port for forcibly exhausting the air inside the furnace body is formed at the upper and lower part of the inlet portion, respectively, and an air jetting portion for jetting air toward the air suction port formed at the upper part of the furnace body. It is characterized by being placed on the side of the

[Effect of invention]

According to the present invention, cold outside air that tries to enter the furnace body from below the outlet and/or inlet of the furnace body;
The heated air that is trying to flow out of the furnace from above is sucked in and forcibly exhausted from the air suction ports formed at the bottom and top of the outlet and/or inlet inside the furnace, respectively, thereby eliminating harmful gases. The amount of air contained in the furnace flowing out of the furnace body is significantly reduced. At this time, since air is ejected from the air ejection part disposed on the side of the furnace body toward the air suction port at the top, this ejected air flow moves the inside of the furnace in the direction of the air suction port. heated air is induced, and therefore the furnace air present in the vicinity of the outlet and/or inlet of the furnace body can be evacuated very effectively.

〔Example〕

Hereinafter, the present invention will be explained based on specific embodiments shown in the drawings.

FIG. 1 is a vertical cross-sectional view schematically showing an example of a coating drying oven according to the present invention, and FIG. 2 is a cross-sectional view thereof.

In the figure, reference numeral 1 denotes a tunnel-shaped furnace body formed of a heat insulating wall, and an air curtain (not shown) or the like is formed at an inlet 2 and an outlet (not shown) to heat-seal the furnace body.

In addition, baffle plates 3, 3... are arranged at predetermined intervals in the furnace body 1 to prevent the heated air in the furnace from flowing along the inner wall toward the inlet or outlet. has been done.

4 is a hopper-shaped air suction port formed at the lower part of the inlet section from the inlet 2 of the furnace body 1 to the heating zone where drying is performed at a predetermined heating temperature; Slit-shaped suction holes 4a, 4a, . . . are formed at predetermined intervals along the surface, or, as shown in FIG. 3, a plurality of vanes 5, 5, . are arranged in parallel, and are connected to an exhaust duct 7 with an exhaust fan 6 interposed therebetween.

Reference numeral 8 denotes an air suction port formed at the upper part of the inlet section from the inlet 2 of the furnace body 1 to the heating zone, and is connected to an exhaust duct 10 with an exhaust fan 9 interposed therein. Purification treatment equipment 1
1.

Reference numeral 12 denotes an air jetting section disposed along the left and right side walls 1R and 1L of the inlet section from the inlet 2 of the furnace body 1 to the heating zone, respectively, at predetermined intervals along the longitudinal direction of the furnace body 1. Multiple spouts 13, 13...
is provided.

An air supply duct 14 branched from the exhaust duct 7 is connected to each air jet section 12 , and an air volume adjustment damper 15 is interposed in the air supply duct 14 so that a required amount of air is supplied to the air jet section 12 . Made to be supplied.

16 is an object to be coated such as an automobile body;
As shown in the figure, the material is suspended from a hanger 18 of an overhead conveyor 17 and carried into the furnace body 1, and is continuously conveyed within the furnace body 1 at a predetermined speed.

Note that it is desirable that the distance between the bottom of the workpiece 16 carried into the furnace body 1 by the conveyor 17 and the suction hole 4a formed on the top surface of the air suction port 4 be as narrow as possible, for example, 50 to 100 mm. has been selected.

The above is an example of the construction of a coating drying oven according to the present invention, and its operation will be explained next.

The inside of the furnace body 1 is heated to a high temperature of, for example, about 120 to 200°C, and when the workpiece 16 suspended from the hanger 18 of the conveyor 17 is continuously carried into the furnace body 1 and passed through it. A coating film of thermosetting amino alkyd resin paint, acrylic resin paint, thermosetting epoxy resin paint, polyurethane resin paint, etc. applied to the surface of the object to be coated 16 is baked and cured by reaction.

During this baking, thinner, toluene, and other organic solvents and hardeners contained in the paint evaporate, and cationic paints generate foul-smelling greasy substances that are harmful to the inside of the furnace body 1. Gas is generated.

Here, since the inlet 2 of the furnace body 1 is wide open, cold outside air is prevented from entering the furnace body 1 from below. In particular, as shown in FIG. 1, when the workpiece 16 is carried in through an air curtain (not shown) or the like, a large amount of outside air is prevented from entering the furnace body 1, but the lower part of the inlet 2 has an air suction port 4 connected to an exhaust duct 7 with an exhaust fan 6 interposed therein, so that invading outside air is forcibly sucked through the suction holes 4a, 4a, . . . of the air suction port 4. be discharged.

Therefore, the outside air that has entered the furnace body 1 is not heated and becomes contaminated air containing harmful gases and flows out of the furnace, and the outside air that has entered the furnace body 1 does not cause the temperature inside the furnace to decrease. will not occur. In addition,
According to experiments, it is optimal to select the suction wind speed of the suction holes 4a, 4a, . . . to be about 20 to 25 m/sec.

In addition, the heated air that has escaped along the ceiling of the furnace body 1 to the vicinity of the inlet 2 is transferred to an air suction port 8 connected to an exhaust duct 10 in which an exhaust fan 9 is installed.
It is sucked in and forcibly discharged, and is sent to the deodorizing and purifying processing device 11 where it is subjected to deodorizing and purifying processing.

At this time, the air supplied through the air supply duct 14 branched from the exhaust duct 7 is supplied from the air suction port 13 of each air jet section 12 disposed on the left and right side walls 1R, 1L of the furnace body 1. 8, an air flow is formed in the upper part of the inlet 2 from the side walls 1R, 1L of the furnace body 1 toward the air suction port 8, and therefore the ceiling of the furnace body 1 The heated air that has escaped along the sides to the upper part of the inlet 2 is guided toward the air suction port 8 by the air flow and is forced to be exhausted very effectively.

As a result, the amount of furnace air flowing out of the furnace through the inlet 2 of the furnace body 1 is significantly reduced.

As described above, according to the above embodiment, air is sucked into the lower and upper parts of the inlet section from the inlet 2 of the furnace body 1 to the heating zone (and/or the outlet section from the heating zone to the outlet), respectively. The ports 4 and 8 are formed, and the side walls 1R and 1L are provided with an air jet section 12 that generates an air flow toward the air suction port 8. The cold outside air that is trying to enter the furnace is forced out through the air suction port 4, and the heated air that is trying to flow out of the furnace body 1 from above the inlet 2 is effectively forced out through the air suction port 8. As a result, the amount of harmful gas generated within the furnace body 1 flowing out of the furnace is significantly reduced.

Note that the air suction port 4 formed at the bottom of the furnace body 1
is not limited to opening along the floor surface of the furnace body 1, but may be opening along the lower left and right side walls 1R and 1L of the furnace body 1, respectively, as shown in FIG.

That is, FIG. 4 is a cross-sectional view showing another example of the coating drying oven according to the present invention. A plurality of suction holes 4a along the lower part of the left and right side walls 1R and 1L of the
Air suction ports 4 having
The floor conveyor 20 that conveys the 6 is configured to suck and discharge air from both left and right sides.

In this case as well, the cold outside air that tries to enter the furnace body 1 from below the inlet 2 enters the left and right air suction ports 4,
Forced exhaust through 4.

[Effect of idea]

As described above, according to the present invention, the cold outside air that attempts to enter the furnace body from below the outlet and/or the entrance of the furnace body, and the heated air that attempts to flow out of the furnace body from above, respectively. Since the air is sucked in and forcibly exhausted from the air suction ports formed at the bottom and top of the outlet and/or inlet inside the furnace, the amount of air inside the furnace that contains harmful gases flowing out of the furnace is significantly reduced. It has the excellent effect of being In particular, since air is ejected from the air ejection part disposed on the side of the furnace body toward the air suction port formed in the upper part, this ejected airflow causes the furnace to flow in the direction of the air suction port. This has the effect that the heated air inside the furnace body can be guided and therefore the furnace air present in the vicinity of the outlet and/or inlet of the furnace body can be exhausted very efficiently.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an example of a drying furnace for coating according to the present invention, Fig. 2 is a cross-sectional view thereof, Fig. 3 is a perspective view showing an example of the configuration of main parts, and Fig. 4 is a painting drying oven according to the present invention. FIG. Explanation of symbols, 1...furnace body, 1R, 1L...side wall, 2...inlet, 4...air suction port, 4a...suction hole, 6...exhaust fan, 7...exhaust duct, 8
...Air suction port, 9...Exhaust fan, 10...Exhaust duct, 14...Air supply duct, 16...Object to be coated, 17, 20...Conveyor.

Claims (1)

[Claims for Utility Model Registration] (1) In a coating drying furnace in which a workpiece 16 to be coated is heated and dried by passing it continuously through a tunnel-shaped furnace body 1 with both ends open, The furnace body 1 is installed at the upper and lower parts of the outlet and/or inlet, respectively.
Air suction ports 4 and 8 for forcibly exhausting the air inside the furnace body 1 are formed, and an air jetting portion 12 for jetting air toward the air suction port 8 formed in the upper part is disposed on the side of the furnace body 1. A drying oven for painting, which is characterized by being equipped with a paint drying oven. (2) The coating drying furnace according to claim 1, wherein the air suction port 4 formed in the lower part of the furnace body 1 is opened along the floor surface of the furnace body 1. . (3) The utility model according to claim 1, wherein the air suction port 4 formed in the lower part of the furnace body 1 is opened along the lower side of the left and right side walls 1R, 1L of the furnace body 1. Paint drying oven. (4) The air sucked from the air suction port 4 formed at the lower part of the furnace body 1 flows into the air jetting portion 12.
The drying oven for coating according to claim 1, wherein the drying oven is configured to eject air from the utility model registered claim 1. (5) The coating drying furnace according to claim 1, wherein the air blowing portions 12 are disposed opposite to each other on both sides of the furnace body 1.