JPS63267473A - Baking drier for coating - Google Patents

Abstract

PURPOSE:To increase the temperature of an object to be coated, keep that increased temperature at a prearranged level and enable baking temperature to be controlled easily by dividing the interior of a drier into three sections and providing a duct in each division so as to allow a hot blast to be blown from each burner. CONSTITUTION:At least two bulkhead doors 13, 14 are provided in a drier 1, and the interior of the drier is divided into three sections, a block close to an inlet 1a, a middle block 1b and a block close to an outlet 1c. Each block is so designed as to be supplied with hot blast from burners 3-5 for the block through ducts 6-8. Consequently, the block close to an inlet 1a can efficiently be maintained to high temperatures by the burner 3 and an object to be coated heated in a short time. In addition, the temperature can stably be held by the bulkhead door 13 in the middle block 1b, while the temperature can be held at low level by the bulkhead door 14 in the block on the outlet side 1c.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is suitable for baking and drying objects coated with special paints such as high-temperature baking fluorine paints such as Kynar 500J (trade name). This article relates to improvements in the drying oven used.

(Prior art) Conventionally, this type of drying oven uses one high-capacity combustion burner.
There are some basics, but as shown in Figure 7,
The ambient temperature inside the furnace is highest at the center of the furnace, and decreases as it approaches the entrance or exit of the furnace. Therefore, the temperature of the object to be coated reaches its highest at the center of the furnace, resulting in excessive baking of the coating, resulting in discoloration and deterioration of quality. In addition, large objects to be coated have a large heat capacity, so the temperature rises slowly, and high-temperature baking fluorine paints cause problems such as cracks in the paint film. To solve this problem, multiple combustion burners are installed in the furnace. A high-capacity combustion burner is installed near the furnace inlet, and one or more low- or medium-capacity combustion burners are installed from the center of the furnace to the outlet, but there are problems as described below. .

(Problems to be solved by the invention) For example, a high-capacity combustion burner is installed near the furnace inlet, a low-capacity combustion burner is installed near the center of the furnace, and one medium-capacity combustion burner is installed near the furnace exit. In the case of a drying oven for coatings, as shown in Figure 8, the atmospheric temperature inside the oven is highest near the oven entrance, but the temperature near the center and outlet of the oven is also maintained at a nearly constant high temperature. Ru. As a result, it was possible to shorten the rise time to a high temperature even for large objects with a relatively large heat capacity, but since the ambient temperature near the center and outlet of the furnace is not much different from the temperature near the furnace entrance, which is the highest temperature, Once the temperature has risen to a certain level, the temperature is maintained for a long time, resulting in excessive baking, resulting in discoloration (yellowing) or deterioration of the quality of the coating film. Note that the same tendency was observed in the case of objects with relatively small heat capacity, such as plate-shaped objects to be coated.

The purpose of the present invention is to solve the above-mentioned problems of the prior art. Therefore, after raising the temperature of the object to be coated in a short time and holding it at a predetermined temperature for a certain period of time, the shape and heat capacity of the object to be coated can be changed. Another object of the present invention is to provide a baking drying oven for painting that can set appropriate baking conditions.

(Means for Solving the Problems) The structure that characterizes the drying oven according to the present invention is that two partition doors that can be opened and closed are provided in the oven to divide the interior of the oven into an area near the entrance, an intermediate area, and an area near the exit. The area was divided into three areas, and each area was equipped with a duct to blow hot air from the combustion burner into it.

(Operation of the means for solving the problem) By dividing the inside of the furnace in this way, it is possible to effectively maintain a high temperature in the heating area near the inlet by a high-capacity combustion burner; The temperature of the object to be coated can be raised in a short time. In the intermediate zone where the object to be coated is maintained at a constant temperature, that is, the holding zone, there is little heat inflow from the heating zone, so the temperature does not rise unnecessarily, and the temperature of the object to be coated does not rise excessively.

Also, when the area on the exit side is used as a low temperature area, it can be easily maintained at a lower temperature than the intermediate area.

(Example) Next, the present invention will be described in detail with reference to the drawings. 1st
The figure and FIG. 2 show a suitable example thereof,
As shown, this drying oven (1) includes a conveyor (2) for transporting the material to be coated through the oven, and a plurality of combustion burners (3), (4), (5), usually three. including. As an example of the conveyor (2), a circulating type conveyor, such as a trolley conveyor, for transporting the object to be coated in a suspended manner is used. Each combustion burner is equipped with a fan which blows hot air heated therein to each area through respective ducts (6), (7), (8).

As shown in Figure 1, the drying oven (1) is equipped with a coating booth (9) on the entrance side of the oven, followed by a setting room (10), and adjacent to it is a coating booth (9) at the entrance. There is Eil (11). There is also a similar shielding door (12) at the exit of the furnace.

The configuration that characterizes this drying oven (1) is as shown in Figure 1.
The furnace is provided with at least a pair of bulkhead doors (13), (14), so that the furnace has three zones: a zone close to the inlet (1a), a middle zone (1b) and a zone close to the outlet (lc). It is classified into And the area on the entrance side (
In la) the hot air from the combustion burner (3) for that area is introduced by a duct (6), and the intermediate area (1b) receives the hot air from the combustion burner (4) by a duct (7) and has an outlet. The side area (IC) is supplied with hot air from the combustion burner (5) by a duct (8).

Note that the combustion burner (3) in the inlet side area (1a) has a higher capacity than the other combustion burners (4) and (5). As shown in Figure 2, in most cases, the hot air outlets (15), (16), and (17) in each area are provided at the bottom, and a register is installed there to adjust the direction and volume of the hot air. Ru. In addition, the suction port (18) at the top of each area, (
19) and (20) also have registers that play a similar role. In the figure, (21) and (22) are shielding plates provided at the bottom, respectively.

Each of the bulkhead doors (13) and (14) is configured to be openable and closable, and therefore, for example, as shown in the figure, each consists of a pair of doors that are each hinged, but they can be moved up and down or left and right as desired. It may also be configured as a sliding door. Each partition door is spaced a certain distance apart to allow passage of the object to be coated, and the opening width thereof is adjusted depending on the shape of the object to be coated.

(13') in FIG. 1 shows the open state. It is preferable to open/close the bulkhead door and adjust the opening width using a control panel driven by a motor or an air cylinder.This has the advantage that it can be opened and closed at any time even during operation when the combustion burner is operating, but it is not possible to open and close it manually. Good too.

In a preferred form, as shown in FIGS. 3 and 4,
In the middle area (1b) of this drying oven there is a bulkhead door (13).
, (14), a bulkhead door (23) which can be opened and closed is provided. This partition S (23) is used instead of one of the partition doors (13) or (14), for example, when the partition door (14) is opened, the partition door (23) is opened.
By closing, the intermediate area (1b) can be narrowed and the outlet area (IC) can be widened. Therefore,
The presence of this partition wall Ii (23) has the advantage that each area in the furnace can be extended or shortened depending on the heat capacity of the object to be coated.

As mentioned above, since the drying oven according to the present invention has the interior divided into three zones, the zone (1a) near the inlet can be effectively kept at a high temperature by its combustion burner (3).
To make it possible to heat up the object to be coated in a short time.

In the middle holding zone (lb), the bulkhead door (13) allows relatively little heat to flow in from the heating zone (1a), so the temperature does not rise unnecessarily, and the temperature of the object to be coated does not rise excessively. . In addition, the area on the exit side (
lc) can be maintained at low temperatures.

Hereinafter, specific examples of implementing the present invention will be shown.

(Specific Example 1) After painting a 4m long building material exterior mullion material with a cross-sectional height of 260m and a width of 150m + hollow shaped material with fluorocarbon paint, it was baked and dried in this drying oven under the conditions shown in Table 1 below. I did it. The measurement results of the ambient temperature and the temperature of the coated object are shown in FIG.

In addition, Table 1 also lists the conditions for the same object to be coated when the bulkhead doors (13) and (14) are not used, and the temperature of the object to be coated in that case is shown by an imaginary line in Figure 5. 6 (Specific Example 2) Plate thickness 2.0mm, height 600rrrra, width 1200m
After painting with a fluorine paint using a panel material for exterior building materials of No. m, baking drying was performed in this drying oven under the conditions shown in Table 2 below, and the temperature measurement results shown in FIG. 6 were obtained.

(Effects of the Invention) Therefore, according to the present invention, three zones with different temperatures are created in the furnace, so as is clear from the above specific example,
The temperature of the object to be coated can be raised in a shorter time than in the past, and the temperature can be maintained at a predetermined temperature for an appropriate amount of time. Therefore, the desirable bake drying requirements of high temperature bake fluorocoat coatings are achieved. Furthermore, even in the case of painting with a paint other than fluorine paint, by dividing the inside of the furnace using the partition door and selectively operating the combustion burner, it is possible to set the conditions of the furnace atmosphere suitable for the paint.

Furthermore, since there is less leakage of high-temperature atmosphere, a high energy saving effect can be expected.

[Brief explanation of the drawing]

FIG. 1 is a plan view schematically showing a baking drying furnace according to an example of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. 1. FIG. 3 is a schematic plan view showing another embodiment, FIG. 4 is a sectional view taken along line BB in FIG. 3, and FIG. 5 is a graph showing temperature measurement results in one specific example in which the present invention is implemented. , FIG. 6 is a graph showing the temperature measurement results in another specific example, and FIGS. 7 and 8 are graphs showing the temperature measurement results in a conventional drying oven, respectively. In the figure, 1: drying oven, 2: conveyor, 3, 4.5: combustion burner, 6.7.8: duct, 13.14: bulkhead door, 23
: Bulkhead door Figure 1 Figure 2 Figure 3 Figure S Figure 6 → Ame Shun (minute)

Claims (2)

[Claims] (1) A drying oven including a plurality of combustion burners for baking and drying the object to be coated and a conveyor for transporting the object to be coated through the furnace, the drying oven having an interior close to its entrance. 3 in the area, the area near the exit and the area in between
At least two openable/closable bulkhead doors are provided to divide the area into sections, and each section is provided with a duct for blowing hot air from a combustion burner for that section. Baking drying oven for painting. (2) The painting baking/drying furnace according to claim 1, further comprising a partition door that can be opened and closed and is used in place of one of the partition doors in the intermediate area.