JPH0543900Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an improvement of a paint drying oven for heating and drying a coated object coated with water-based paint by dipping, electrodeposition, spray painting, etc. .

[Prior art and its problems]

A conventional coating drying oven 1 of this kind shown in FIG.
For example, a water-based paint with a paint temperature of 25°C to 30°C is applied by dip coating in the coating tank 2, and the coating film of the objects 4, 4, etc. to be coated, which are transported through the setting room 3, is heated and dried. The inside of the drying oven 1 has a high temperature and humid atmosphere due to water, solvent, etc. evaporated from the coating film of the object 4 to be coated.

Incidentally, an air curtain 5 is provided between the drying oven 1 and the setting room 3, but even if this air curtain 5 is installed, it will not contain water vapor or solvent vapor from inside the drying oven 1 in such a large amount that it is close to a saturated state. However, high-temperature (for example, 150 to 180 degrees Celsius) air flows out and flows into the setting room 3, raising the temperature in the setting room 3 to approximately 30 to 60 degrees Celsius, and the humidity is also extremely high. becomes.

When the object to be coated 4 whose temperature is lower than the dew point temperature of the air in the setting room 3 is brought into such a setting room 3, dew condensation will occur on the surface of the object to be coated. This has had the disadvantage of causing a vapor wash phenomenon in which the water or solvent components that have been absorbed wash away the painstakingly formed coating film, causing the coating to disappear.

Particularly in winter, the temperature of the paint in the paint tank 2 increases.
The temperature of the object to be coated 4, which is dip-coated with a water-based paint at 25°C to 30°C and brought into the setting room 3, is 5°C to 5°C in the first half of the setting room 3 due to the low outside temperature in winter. It is cooled as it passes through a room where the atmosphere is around 15°C, and in the latter half of the setting room 3, it passes through an atmosphere that is hot and humid due to the furnace air flowing out from the drying furnace 1. During this process, dew condensation occurred almost without exception on the surfaces of the objects 4 to be coated whose temperature was certainly lower than the dew point temperature. In addition, the water and solvent may not evaporate sufficiently from the coating film of the object 4 in the setting room 3, and the object 4 may be left in the drying oven 1 at a high temperature with the coating still wet due to dew condensation. There was a problem in that the water, solvent, etc. in the paint film evaporated all at once, resulting in paint film defects such as wrinkles and foaming.

[Purpose of invention]

Therefore, the present invention effectively prevents the hot and humid furnace air from flowing into the setting room, introduces fresh air, and prevents condensation on the surface of the workpiece being transported through the setting room. It is an object of the present invention to provide a drying oven for coating that prevents the occurrence of paint film defects such as wrinkles and foaming.

[Structure of the idea]

In order to achieve this objective, the present invention has been developed in a coating drying oven for heating and drying a workpiece coated with a water-based paint and transported through a setting room. A position where the entrance and exit are provided below the furnace body, and the exhaust duct that sucks and exhausts the furnace air flowing out from the furnace body between the furnace body inlet and the furnace body is out of the range of conveying the objects to be coated. An opening is formed in the setting room, and fresh air is introduced into the setting room to maintain the temperature in the setting room substantially constant with the coating temperature, and to create an air flow toward the furnace main body side. It is characterized by being provided with an air supply duct for introduction.

[Effect of invention]

In the paint drying oven according to the present invention, the oven body is first formed into an angle-shaped oven, and the inlet and outlet of the oven body are provided below the oven body, so that the hot and humid oven air flowing out from the oven body flows into the oven body. It collects and accumulates between the inlet and the furnace body. In addition, fresh air is introduced from the air supply duct installed in the setting room to create a flow of air from inside the setting room toward the furnace main body, so that the furnace air flowing out from the furnace main body flows toward the setting room. It is collected on the furnace main body side without being diffused.

Then, the furnace air that flows out of the furnace body, stays and is collected in this way is sucked and discharged through an exhaust duct provided between the inlet of the furnace body and the furnace body.

This effectively prevents the hot and humid furnace air flowing out of the furnace body from flowing into the setting room, and prevents dew condensation from forming on the surface of the workpiece being transported through the setting room. It can definitely be prevented.

At this time, high-temperature air containing a large amount of water vapor and solvent vapor flows into the exhaust duct, so dew condensation and tar adhere to the opening, but the exhaust duct does not move beyond the conveyance area of the workpiece. Since the opening is formed at the position, there is no possibility that dew condensation or tar will fall onto the object to be coated as it is being conveyed, resulting in poor coating.

In addition, the hot and humid furnace air that remains between the furnace inlet and the furnace body is constantly sucked out through the exhaust duct, so there is no chance of condensation forming on the surface of the workpiece being transported through the exhaust duct. .

Furthermore, fresh air is constantly introduced into the setting room, and water and solvent components are sufficiently evaporated from the paint film of the workpiece being transported through the setting room, preventing dew condensation from forming on the paint film. The paint film of the object is transported into the drying oven in a substantially dry state, and therefore, paint film defects such as wrinkles and foaming do not occur on the paint film.

Furthermore, fresh air introduced into the setting room from the air supply duct maintains the temperature of the setting room at approximately the same level as the painting temperature, so even in the winter, objects to be coated are transported to the setting room. The temperature of the vapor wash does not drop to an extremely low level, so there is no condensation on the surface of the workpiece even when it comes to the inlet side of the furnace body, where the temperature is relatively high, which can cause paint film defects. It is possible to reliably prevent the phenomenon from occurring.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described based on the drawings.

FIG. 1 is an explanatory diagram showing an example of a coating drying oven according to the present invention.

Note that parts common to those in FIG. 4 are given the same reference numerals and detailed explanations are omitted.

In the present invention, the oven body of the drying oven 1 is formed into a chevron-shaped oven, and the inlet 6 and outlet (not shown) are provided below the oven body 1a, and between the inlet 6 and the oven body 1a. An exhaust duct 7 is provided for sucking and discharging the furnace air flowing out from the furnace body 1a, and the setting room 3 to which the workpiece 4 coated with water-based paint in the coating tank 2 is transported is equipped with a setting room 7. An air supply duct 8 for introducing fresh air is provided to generate a flow of air from inside the furnace 3 toward the furnace main body 1a side.

The exhaust duct 7 is connected to the inside of the furnace body at a position higher than the floor surface 9 of the furnace body 1a, and sucks and exhausts high-temperature and humid furnace air flowing out from inside the furnace body 1a with the exhaust fan 11. The discharged high-temperature (for example, about 150°C) air is sent into the heat exchanger 12, and the fresh air introduced into the setting room 3 from the air supply duct 8 with the air supply fan 13 interposed is about 25℃. It is designed to be heated to about 35°C to 35°C.

In addition, as shown in FIGS. 2 and 3, the opening position of the exhaust duct is set so that dew condensation, tar, etc. that adhere to the inside of the furnace do not fall and stain the workpiece 4. is formed at a position outside the transport range of the object 4 to be coated.

However, by heating and drying the object 4 dip-coated in the coating tank 2 shown in FIG. When furnace air containing a large amount of water vapor and solvent vapor flows out from inside the furnace body 1a of the drying furnace 1, which has a high temperature and humidity atmosphere, the air flows into the exhaust duct 7.
is sucked and discharged to the outside.

At this time, the furnace air with a light specific gravity flowing out from the inside of the furnace body 1a of the drying furnace 1 formed as a mountain-shaped furnace accumulates in the upper part between the inlet 6 and the furnace body 1a, so the furnace body The gas is efficiently sucked and discharged through an exhaust duct 7 that is open and connected to the furnace body at a position higher than the floor surface 9 of 1a.

As a result, the humidity between the inlet 6 and the furnace body 1a is significantly reduced, thereby reliably preventing dew condensation from forming on the surface of the workpiece 4 being transported there.
At this time, dew condensation and tar adhere to the opening of the exhaust duct, but since the exhaust duct is opened at a position that is outside the conveyance range of the workpiece, condensation does not form on the workpiece being conveyed. There is no chance of paint defects caused by falling tar or resin.

In addition, fresh air is introduced into the setting room 3 from the air supply duct 8, and the setting room 3 is brought into a positive pressure state, and air flows from the setting room 3 toward the furnace main body 1a. Therefore, the furnace air flowing out from the furnace body 1a can be prevented from diffusing to the setting room 3 side, and at the same time, the furnace air flowing out can be removed from the exhaust duct 7.
It can be collected to the side and effectively sucked and discharged.

This ensures that the hot and humid furnace air flowing out from inside the furnace body 1a flows into the setting room 3 and causes dew condensation on the surface of the workpiece 4 being transported through the setting room 3. This eliminates the problem of vapor wash phenomenon caused by water or solvent components contained in dew condensation.

In addition, fresh air is always introduced into the setting room 3, so that water and solvent components are sufficiently evaporated from the coating film of the workpiece 4 being conveyed there, and the inside of the setting room 3 and the furnace body are thoroughly evaporated. From the inlet 6 to the furnace body 1a
Since there is no condensation on the coating film of the object 4 to be coated while it is being transported into the furnace body 1a, the coating film of the object 4 to be coated is carried into the furnace main body 1a in an almost dry state, and therefore the coating film is There is no chance of paint film defects such as wrinkles or foaming on the surface.

Furthermore, the setting room 3 is connected from the air supply duct 8.
The fresh air introduced into the chamber is heated to a temperature of 25°C to 35°C, which is approximately equal to the paint temperature in the painting tank 2, by heat exchange with the high temperature air of about 150°C discharged from the exhaust duct 7.
℃, even in winter, the temperature of the objects to be coated that are dip-coated in the coating tank 2 and transported to the setting room 3 does not drop below 10℃, so the temperature is relatively low. Even when it comes to the inlet 6 side of the high furnace body, no dew condensation occurs on the surface of the object to be coated, and it is possible to reliably prevent the occurrence of the vapor wash phenomenon that causes defects in the coating film.

In addition, from the air supply duct 8 to the setting room 3
By dehumidifying the fresh air introduced into the room, you can more reliably prevent condensation from forming.

[Effect of idea]

As described above, according to the present invention, the hot and humid furnace air flowing out from the furnace body of the drying furnace is effectively prevented from flowing into the setting room, and the drying furnace air is transported through the setting room. It has the effect of reliably preventing dew condensation from forming on the surface of the object being coated, and the surface of the object coated with water-based paint is prevented from forming due to the water or solvent components contained in the condensation. It is possible to prevent the vapor washing phenomenon from occurring.

In addition, the hot and humid furnace air that remains between the furnace inlet and the furnace body is constantly sucked out through the exhaust duct, so there is no chance of condensation forming on the surface of the workpiece being transported through the exhaust duct. .

Furthermore, fresh air is constantly introduced into the setting room, and water and solvent components are sufficiently evaporated from the paint film of the workpiece being transported through the setting room, so there is no chance of condensation forming on the paint film. The coating film of the object to be coated is carried into the drying oven in a substantially dry state, and therefore, coating defects such as wrinkles and foaming do not occur on the coating film.

Furthermore, the fresh air introduced into the setting room is heated to a temperature approximately equal to the temperature of the paint in the coating tank, so that the temperature of the objects to be coated transported through the setting room does not become extremely low even in winter. This prevents condensation from forming on the surface of the object to be coated, even when it comes to the inlet of the furnace body, where humidity is relatively high.
The vapor wash phenomenon that causes paint film defects is reliably prevented.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an example of a coating drying oven according to the present invention, FIGS. 2 and 3 are sectional views taken along the line A--A, and FIG. 4 is an explanatory diagram of the prior art. Explanation of symbols, 1...Drying oven, 1a...Furnace body,
2... Paint tank, 3... Setting room, 4...
...Object to be coated, 6...Inlet, 7...Exhaust duct, 8...
...Air supply duct.

Claims (1)

[Scope of utility model registration request] In a coating drying furnace for heating and drying a workpiece 4 coated with a water-based paint and transported through a setting room 3, the furnace body is formed into a chevron-shaped furnace, and its entrance and exit are located below the furnace body 1a. An exhaust duct 7 is formed between the inlet 6 of the furnace body and the furnace body 1a to suck and exhaust the furnace air flowing out from the furnace body 1a. and the setting room 3.
is provided with an air supply duct 8 for introducing fresh air that maintains the temperature in the setting room 3 substantially constant with the coating temperature and generates an air flow toward the furnace main body 1a side. A paint drying oven characterized by: