JPH11197580A - Coating drying furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To recover the heat released from a furnace casing and to enable the preheating of fresh air by providing a coating drying furnace with a passage in which the fresh air used for heating means passes along the wall surface of the furnace casing in which the material to be dried is transported. SOLUTION: The furnace casing 1 of which the respective wall surfaces 111 of the side walls, ceiling and floor are formed of panels is internally provided with air feed ducts 122a and discharge ducts 122b along the extension direction of the furnace casing 11 on both right and left sides thereof in order to bake an automotive body B which is the material to be dried at 140 deg.C. The hot air is supplied from the heater to the air feed ducts 122a to supply the hot air into the furnace casing 11. Further, the outer sides of the wall surfaces 111 of the furnace casing 11 are provided with air ducts 13 along the extension direction of the furnace casing 11. The fresh air is introduced via a filter and an air feed fan into these air ducts 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating and drying furnace used in a coating line for an automobile body or an automobile part, and more particularly to an energy-saving coating and drying furnace capable of recovering heat from the furnace body and preheating fresh air.

[0002]

2. Description of the Related Art As a conventional coating and drying furnace of this type, for example, a chevron furnace 1 as shown in FIG. 4 is known. Yamagata furnace 1
In FIG. 1, a furnace body is formed in a mountain-shaped passage shape in a side view as shown in FIG. 1A, and hot air is convected into an internal space by heating means (not shown) including a gas burner, a duct, and a heat exchanger. Then, an object to be coated such as an automobile body is conveyed from left to right in FIG. With such a chevron furnace 1, hot air or smoke is prevented from escaping out of the furnace from the inlet 112 or the outlet 113 of the drying furnace, and it is possible to contribute to energy saving and environmental improvement.

The general cross section of the angle furnace 1 has the structure shown in FIG. That is, in the furnace body through which the body B passes, the panel 111 is provided on each of the side walls, the ceiling, and the floor via the aggregate, and the heat insulating material (heat insulating material) 14 is provided on the outer surface of the panel 111. To prevent the heat in the furnace from being released. A hot air supply duct 122a and an exhaust duct 122b are provided on both left and right sides of the furnace along the extending direction of the furnace body.

[0004]

An electrodeposition drying furnace, an intermediate coating drying furnace, a top coating drying furnace, and the like are installed in a coating line of an automobile assembly plant. 4) or is mounted on the coating hanger and is conveyed in the line by the floor conveyor or the overhead conveyor. Therefore, the floor conveyor C and the overhead conveyor are also laid in the coating and drying furnace 1.

For this reason, in the floor conveyor C as shown in FIG. 4, it is necessary to provide a load-bearing structural member for laying the conveyor C on the floor surface of the drying furnace 1, and it is not shown. In a drying furnace in which an overhead conveyor is laid, it is necessary to provide a structural member for load bearing of the conveyor on the ceiling.

That is, in the conventional coating and drying furnace 1, the floor structure and the ceiling structure of the drying furnace are complicated, and there is a part where the heat insulating material 14 is not provided, so that heat radiation from the part is suppressed. It was difficult.

[0007] The present invention has been made in view of such problems of the prior art, and an object of the present invention is to provide an energy-saving paint drying furnace capable of recovering heat radiation from a furnace body and preheating fresh air. And

[0008]

In order to achieve the above object, a coating and drying furnace of the present invention is used as a heating means along at least one wall surface of a furnace body into which an object to be dried is conveyed. A passage through which fresh air flows is provided.

In the coating and drying furnace of the present invention, since a fresh air passage is provided on the wall surface of the furnace body, the heat released from the wall surface of the furnace body is transmitted to the fresh air passing through the passage, whereby The fresh air can be preheated. That is, since the fresh air used for the heating means is preliminarily heated using the excess heat energy, the heat energy in the heating means can be saved by that much.

[0010] The structure of the passage according to the present invention is not particularly limited, but in the coating and drying furnace according to claim 2, the passage is formed of an air duct, and at least the wall of the furnace body other than the wall surface provided with the air duct is provided. The wall is provided with a heat insulating material. In the second aspect of the present invention, it is more preferable to provide an air duct on a wall surface where it is difficult to suppress heat radiation from the furnace body by the heat insulating material. At this time, a heat insulating material may be provided also in the air duct.

Further, regarding the structure of the passage according to the present invention,
According to a third aspect of the present invention, the passage is a gap between at least two layers of the heat insulating material provided on a wall surface of the furnace body. Utilizing the fact that heat radiation from the furnace body cannot be sufficiently prevented with only one layer of heat insulating material, fresh air is preheated by the heat energy radiated from the inner layer.

Although the configuration of the heating means according to the present invention is not particularly limited, in the coating drying furnace according to the fourth aspect, the combustion system having a combustion burner and the hot air from the combustion system are directly or indirectly connected. A hot air circulating system that is connected and circulates hot air that heats the object to be dried that passes through the furnace body. That is, the coating drying oven of the present invention can be applied to either a direct hot air drying oven or an indirect hot air drying oven.

In the present invention, the supply destination of the preheated fresh air is not particularly limited. In the coating and drying furnace according to the fifth aspect, the fresh air passes through the passage and is preheated. The heat is exchanged with the hot air of the combustion system, and the hot air is supplied as hot air of the hot air circulation system. That is, it can be supplied into the furnace as heating air for the indirect hot air drying furnace.

In this case, as in the coating drying oven according to claim 6, a flow path on the hot air side of the combustion system of a heat exchanger for exchanging heat between the preheated fresh air and the hot air of the combustion system. Is provided with an oxygen concentration sensor, and when the oxygen concentration detected by the oxygen concentration sensor is higher than a predetermined value,
More preferably, the hot air of the combustion system that has passed through the heat exchanger is recovered as combustion air for the combustion system. In this way, the hot air having a sufficient oxygen concentration for combustion can be reused without being discarded, and since the temperature is sufficiently high, the heat energy in the heating means can be saved correspondingly.

According to a seventh aspect of the present invention, the supply destination of the preheated fresh air is such that the fresh air passes through the passage and is preheated, and then is supplied to the combustion air of the combustion system. It is characterized by being supplied as. Since the preheated fresh air is burned, heat energy for raising the temperature to the required temperature is reduced by that much, and energy saving can be achieved.

The coating drying oven of the present invention is preferably used for an electrodeposition drying oven, an intermediate coating drying oven and a top coating drying oven.

[0017]

According to the first to seventh aspects of the present invention, the fresh air used for the heating means is pre-heated using the excess heat energy, so that energy saving can be achieved.

According to the sixth aspect of the present invention, hot air having a sufficient oxygen concentration for combustion can be reused without being discarded, so that more energy saving is achieved.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the coating and drying furnace of the present invention, FIG. 2 is a cross-sectional view along the line AA of FIG. 1, and FIG. FIG. 1B is an enlarged sectional view of a portion B in FIG.

This embodiment shows an embodiment in which the coating drying oven of the present invention is applied to a top coating drying oven.
As shown in FIG. 2, the automobile body B is transported in the furnace while being mounted on the coating trolley TD.

The overcoating / drying furnace 1 of this embodiment is shown in FIG.
As shown in FIG. 2, the general cross section of the furnace body 11 shown in FIG. 2 is constructed of aggregate, and the side walls 111, the ceiling, and the floor between the walls 111 are formed by panels. . A heat insulating material (heat insulating material) 14 is provided on the entire left and right side walls and the outer surface of the ceiling 111 to prevent heat radiation in the furnace.

Further, in the furnace body 11, an air supply duct 122a and an exhaust duct 122b are provided on both left and right sides along the extending direction of the furnace body 11 in order to bake the body B at, for example, 140 ° C. Have been. Air supply duct 122
Hot air is supplied to a from the heating device (heating means) 12 shown in FIG. The exhaust duct 122b is for sucking the hot air supplied into the furnace body 11 and discarding it outside the system, or for circulating the hot air to the heating device 12 described above.

In this embodiment, an air duct 13 is provided outside the floor surface 111 of the furnace body 11 along the direction in which the furnace body 11 extends. Further, the above-described heat insulating material 14 is provided so as to cover the air duct 13.
The leg stays are attached via. Fresh air is introduced into the air duct 13 through the filter 131 and the air supply fan 132 shown in FIG. The fresh air thus introduced and passing through the air duct 13 is supplied to the air supply fan 133 shown in FIG.
Then, the heat is absorbed by the heat exchanger 121d to become hot air, and then supplied to the hot air circulation system 122.

The heating device 12 of this embodiment is of an indirect type deodorizing system, and includes a combustion burner 121a, a heat exchanger 12
1b, 121 and a supply fan 121c, and a supply duct 122 provided in the furnace body 11.
a, an exhaust duct 122b, a filter 122c, and a hot air circulation system 122 having an air supply fan 122d.

The combustion system 121 includes a combustion burner 121a.
The high-temperature gas burned in the above is sent to the heat exchanger 121d through the heat exchanger 121b, where the heat exchange with the fresh air is performed to raise the temperature of the fresh air, and then the exhaust gas is exhausted from the switching damper 123a.

However, if the oxygen concentration detected by the oxygen concentration sensor 123d installed in the outlet duct of the heat exchanger 121d is higher than a predetermined value (a value sufficient for combustion by the combustion burner 121a), the damper The switching damper 123a is closed and the switching damper 123b is opened by the controller 123c, and the combustion gas to be exhausted is collected and the combustion burner 12
1a. As described above, when the oxygen concentration of the high-temperature combustion gas is a value sufficient for reburning, energy can be saved by recovering the oxygen concentration.

As the combustion air supplied to the combustion burner 121a, hot air from an exhaust duct in the furnace body 11 is used. After the heat is exchanged with the combustion gas by the heat exchanger 121b, the combustion air is supplied to the combustion burner 121a. Supplied.

On the other hand, the hot air circulation system 122
After drawing in hot air from the exhaust duct 122b in the furnace body 11 using the filter body 22d and filtering it with the filter 122c, the furnace body 1
1 to the air supply duct 122a.

The heating device 12 is not particularly limited in the present invention, and a direct type hot blast stove can be applied in addition to the above-described indirect type hot blast stove. , Dark red zone, convection zone etc.
Various types can be applied.

Next, the operation will be described. First, the combustion system 121
The air supply fan 121c is operated to suck air from the exhaust duct 122b in the furnace body 11 and the combustion burner 12
1a, and ignites the combustion burner 121a. As a result, combustion gas is generated.

The air supply fan 12 of the hot air circulation system 122
2d is operated, air is sucked from the exhaust duct 122b in the furnace body 11 and filtered, and then the air is supplied to the air supply duct 122.
supply to a. This activates the circulation cycle.

Further, the air supply fan 132 is operated to inhale fresh air and supplied to the air duct 13, and the air supply fan 133 is operated to operate the air duct 1.
3 is supplied to the hot air circulation system 122 via the heat exchanger 121d.

Since the temperature of the fresh air passing through the heat exchanger 121d is increased by the combustion gas, the heated fresh air is supplied from the air supply duct 122a into the furnace body 11 by the hot air circulation system 122. The body B is baked at, for example, 140 ° C.

At this time, the fresh air passing through the heat exchanger 121d absorbs the heat radiation in the furnace body 11 by passing through the air duct 13 and slightly rises in temperature, so that the heat efficiency in the heat exchanger 121d is improved. As a result, the output of the combustion burner can be reduced more than before.

The oxygen concentration of the combustion gas absorbed by passing through the heat exchanger 121d is detected by the oxygen concentration sensor 123d, and the output value is sent to the damper controller 123c.

The threshold value of the oxygen concentration is stored in advance in the damper controller 123c.
The measured value input from 23d is compared with the threshold, and if the oxygen concentration is equal to or higher than the threshold,
The switching damper 123a is closed and the switching damper 123 is closed.
b, the combustion gas is recovered, and the combustion burner 1
21a. Since the combustion gas has a sufficiently high temperature, the combustion efficiency of the combustion burner is improved, and energy saving can be achieved here.

When the measured value inputted from the oxygen concentration sensor 123d is lower than the threshold value, it is not suitable as combustion air, so that the switching damper 123a is opened and the switching damper 123b is opened. Close and exhaust the combustion gases as they are.

The coating and drying furnace of the present invention is not limited to the above-described embodiment, but may be modified as shown in FIG. 3, for example. In the embodiment shown in the figure, as the fresh air passage, instead of the air duct 13 shown in FIG. 1, heat insulating materials 14a, 14b having a two-layer structure are used.
Is employed.

That is, outside the wall panel 111,
A first heat insulating material 14a is provided, and the first heat insulating material 14a is provided.
a small space 13 is provided outside of the second heat insulating material 14b.
Are being stretched out.

Although the specific means for providing the gap 13 between the two-layer heat insulating materials 14a and 14b is not particularly limited, in the present embodiment, as shown in FIG.
If the channel material 14c is attached to the outside of the furnace 4a and the second heat insulating material 14b is attached to the other end of the channel material 14c, the space 13
The heat insulating materials 14a and 14b having a two-layer structure having the above structure are formed. The stays of the legs are attached via heat insulating materials 14a and 14b.

Although not shown, the gap 13
At one end in the furnace body extending direction, a filter 131 for introducing fresh air and an air supply fan 132 shown in FIG. 1 are provided so that fresh air is introduced into the gap 13 and the other part in the furnace body extending direction. The air supply fan 1 shown in FIG.
33 is provided, and fresh air preheated through the gap 13 is supplied to the hot air circulation system 122.

Even with this configuration, the amount of heat radiated from the furnace body 11 increases as the temperature inside the furnace body 11 increases, so that the fresh air can be preheated by this heat, Energy saving can be achieved by using the fresh air heated in this way as air for the hot air circulation system 122.

The embodiments described above have been described in order to facilitate understanding of the present invention, but not to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, in the above-described embodiment, the fresh air that has passed through the air duct 13 and the air gap 13 is supplied to the hot air circulation system 122. It can also be used as air. Further, the air may be branched into hot air circulation air and combustion air.

In the above-described embodiment, the coating and drying furnace 1
Although the floor conveyor C is illustrated as a transporting unit in the above, an overhead conveyor can be applied. Further, in addition to the top coat drying oven, the present invention can be applied to an intermediate coating drying oven or an electrodeposition drying oven.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a coating and drying furnace of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a cross-sectional view and a main part enlarged cross-sectional view showing another embodiment of the coating and drying furnace of the present invention.

FIG. 4 is a side view and a sectional view showing a conventional chevron drying furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Paint drying furnace 11 ... Furnace body 111 ... Wall surface 12 ... Heating device (heating means) 121 ... Combustion system 121a ... Combustion burner 122 ... Hot air circulation system 122a ... Air supply duct 122b ... Exhaust duct 13 ... Air duct, air gap ( Passage) 131 ... Filter 132,133 ... Air supply fan 14,14a, 14b ... Heat insulation material B ... Car body (dry material) C ... Floor conveyor TD ... Painting trolley

Claims (7)

[Claims] 1. A coating and drying furnace, wherein a passage through which fresh air used for heating means flows is provided along at least one wall surface of a furnace body into which an object to be dried is conveyed. 2. The coating and drying apparatus according to claim 1, wherein said passage comprises an air duct, and a heat insulating material is provided on at least a wall surface of said furnace body other than a wall surface provided with said air duct. Furnace. 3. The coating and drying furnace according to claim 1, wherein said passage is a gap between at least two layers of heat insulating material provided on a wall surface of said furnace body. 4. The heating means includes: a combustion system having a combustion burner; and a hot air that is directly or indirectly connected to hot air from the combustion system and heats the object to be dried passing through the furnace. The coating and drying furnace according to any one of claims 1 to 3, further comprising: a hot air circulation system for circulating. 5. The fresh air is preheated by passing through the passage, heat-exchanged with hot air of the combustion system, and supplied as hot air of the hot air circulation system. Paint drying oven as described. 6. An oxygen concentration sensor is provided in a flow path on a hot air side of said combustion system of a heat exchanger for exchanging heat between said preheated fresh air and hot air of said combustion system. The coating and drying furnace according to claim 5, wherein when the detected oxygen concentration is higher than a predetermined value, the hot air of the combustion system that has passed through the heat exchanger is recovered as combustion air of the combustion system. 7. The coating and drying furnace according to claim 4, wherein the fresh air is supplied as combustion air for the combustion system after being preheated through the passage.