JPH0677706B2 - Exhaust gas recirculation type coating boots - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coating booth in which an object to be coated is continuously passed through for coating treatment, and more particularly to a structure of a coating booth having a flash-off zone.

[Prior Art] A coating booth for coating an object to be coated such as an automobile body has a straight structure in the past, and the object to be coated carried in from the entrance goes straight through the coating booth and goes through each treatment zone. After that, it is carried out from the exit.

For example, in the "Painting Technology" November 1985 issue, page 72, a painting booth for automobile bodies with a straight structure is shown.
This coating booth is usually constructed, for example, as shown in FIG. An automobile body as the article to be coated 2 is conveyed to the coating booth 1 from the entrance to the exit. The coating zone is composed of a dusting zone 3 for removing dust of the automobile body 2, a pre-coating zone 4, a flash-off zone 5 for solvent evaporation of the coating film, and a post-coating zone 6 from the entrance side. An air supply device 7 and an exhaust device 8 are provided to supply and exhaust air to each zone.

Conventionally, the exhaust gas from each zone has been exhausted as it is after being subjected to appropriate environmental treatment.

[Problems to be Solved by the Invention] In the coating booth having the above zone structure, the flash-off zone is a zone for solvent evaporation of the coating film, and basically does not include dust such as paint mist. In the flash-off zone, exhaust gas recirculation should be possible. The exhaust gas recirculation should save the heating energy of the supply air.

However, in reality, exhaust gas recirculation in the flash-off zone was not possible due to the following reasons. There are coating zones 4 and 6 before and after the flash-off zone 5. Depending on the imbalance between the air supply amount and the exhaust amount in the coating zones 4 and 6 before and after the flash-off zone 5, they flow into the flash-off zone 5 or pass through the flash-off zone 5. A mixed flow occurs. The paint mist that scatters when painting in each painting zone 4, 6
There was a phenomenon of flowing into the flash-off zone 5 by riding on the oblique flow. Therefore, flash-off zone 5
In order to recirculate the exhaust gas, the paint mist needs to be collected almost completely from the circulating air, but a high-efficiency filter is required to collect the paint mist having a small particle size. However, when a high-efficiency filter is used, clogging occurs early and the filter life is too short, making it difficult to put into practical use. Eventually, even in the flash-off zone, exhaust gas had to be exhausted without being circulated, resulting in an inefficient operation method in terms of thermal energy.

An object of the present invention is to prevent the paint mist from flowing into the flash-off zone and enable exhaust gas recirculation in the flash-off zone to save energy.

[Means for Solving Problems] An exhaust gas recirculation type coating booth of the present invention which achieves this object is provided with a pre-coating zone, a flash-off zone for solvent evaporation, and a post-coating zone in the conveying direction of an object to be coated. In the coating booth provided in this order, the coating booth has a U-turn structure,
In other words, it is constructed in a structure that has a forward path and a return path of the object to be coated,
An exhaust gas recirculation is provided in which a flash-off zone is arranged in the U-turn portion, a front coating zone and a post-coating zone are adjacently arranged, and exhaust gas from the flash off zone is circulated to the flash off zone again in the flash off zone. A device is provided so that the adjacent pre-painting zone and post-painting zone communicate with each other via the flash-off zone, and also directly communicates with each other through the communication passage formed in the partition plate between the pre-painting zone and the post-painting zone. It is made up of.

[Operation] In the above coating booth, the coating booth has a U-turn structure, the coating zones before and after the flash-off zone are adjacent to each other, and the adjacent coating zones are directly communicated with each other. Even if occurs, the air flow only occurs through the direct communication passage, and the air flow through the flash-off zone, that is, the mixed flow in the flash-off zone does not occur. Since there is no mixed flow, the paint mist in the paint zone does not flow into the flash-off zone. As a result, exhaust gas recirculation in the flash-off zone is possible, and the exhaust gas recirculation device always circulates the same air in the flash-off zone, saving energy.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a coating booth according to an embodiment of the present invention, and shows a coating booth for an automobile body etc. to which the present invention is applied.

In the figure, 11 indicates the entire exhaust gas recirculation type coating booth, and 12 indicates the internal coating chamber. The vehicle body or the like as the article to be coated 14 is conveyed by the conveyor 13 into the coating chamber 12, and after being subjected to predetermined processing, it is conveyed out.

The coating chamber 12 is used for transporting the object to be coated 14 (in the direction of the arrow in the figure).
From the inlet side, it is divided into a dusting zone 15 for removing dust on the article to be coated 14, a pre-coating zone 16 for performing a base coat, a flash-off zone 17 for evaporating a solvent in the coating film, and a post-coating zone 18 for performing a clear coat. There is.

The coating booth 11, more specifically, the coating chamber 12, has a U-turn structure, that is, a structure having a forward path and a return path in the transport direction of the object to be coated 14. A flash-off zone 17 is provided in the U-turn portion, and a front coating zone 16 and a rear coating zone 18 located in front of and behind the flash-off zone 17 are disposed adjacent to each other.

A partition plate 19 separates the dusting zone 15, the pre-painting zone 16 and the post-painting zone 18, but a partition wall 19
Communication paths (openings in the present embodiment) 19a, 19a are provided in the. Therefore, the pre-painting zone 16 and the post-painting zone 18
In addition to being communicated with via the flash-off zone 17, they are directly communicated with the partition plate 19 via a communication path 19a.
The front coating zone 16 and the flash-off zone 17, and the flash-off zone 17 and the post-coating zone 18 are separated by a partition plate 20 leaving the passage portions 20a, 20a of the article to be coated 14.

The dusting zone 15 and the pre-painting zone 16 and the post-painting zone 18 are provided with air conditioners 21a and 21b, air supply fans 22a and 22b, and air supply ducts 23a and 23b, respectively.
Exhaust devices 27a and 27b provided with a and 24b, exhaust ducts 25a and 25b, and exhaust fans 26a and 26b are provided.

Flash-off zone 17 has flash-off zone 17
An exhaust gas recirculation device 28 is provided to recirculate the exhaust gas from the exhaust gas to the flash-off zone 17. Exhaust gas recirculation device 28
Is composed of a circulation duct 29, a solvent adsorber 30, a heater 31, and a circulation fan 32.

The operation of the apparatus of the above embodiment will be described.

The car body 14 is conveyed to the conveyor 13 and the coating booth 11
Then, dust is removed from the car body 14 in the dusting zone 15 first. The base coat is applied in the pre-coating zone 16, the solvent in the formed coating film is evaporated in the next flash-off zone 17, and the clear coat is applied in the post-coating zone 18 to complete the coating.

Air is supplied and exhausted in the dusting zone 15, the pre-painting zone 16 and the post-painting zone 18, respectively, but an air pressure difference may occur between the dusting zone 15 and the pre-painting zone 16 due to the imbalance between the air supply amount and the exhaust amount. However, since the two are directly communicated with each other by the communication passage 19a, even if a pressure difference occurs, the air mainly flows from the higher pressure side to the lower pressure side mainly through the communication passage 19a.

Therefore, almost no flow occurs between the flash-off zone 17 and the pre-painting zone 16 or the post-painting zone 18, and no mixed flow occurs in the flash-off zone 17. Therefore, the paint mist in the pre-painting zone 16 or the post-painting zone 18 does not flow into the flash-off zone 17. Since there is no paint mist, the exhaust gas in the flash-off zone 17 can be circulated, and the exhaust gas is circulated by the exhaust gas recirculation device 28,
The heat energy of the exhaust gas is effectively used. As for the exhaust gas, basically the same air is circulated because there is no air inflow from the coating zones 16 and 18, and the heating by the heater 31 accelerates the solvent evaporation from the coating film, and at the same time, the solvent adsorber 30. The solvent is adsorbed.

[Effect of the Invention] According to the exhaust gas recirculation type coating booth of the present invention, the coating booth has a U-turn structure, and the U-turn portion is a flash-off zone, the coating zones before and after that are adjacent to each other, and both coating zones are flushed. In addition to the communication via the off-zone, the direct communication was made via the communication passage provided in the partition plate between the adjacent zones, so that the mixed flow caused by the air pressure difference in each coating zone hardly flows into the flash-off zone. Therefore, the paint mist is not included in the recirculation exhaust gas in the flash-off zone, and the exhaust gas can be easily recirculated. As a result, energy such as heating of the air supply can be saved as compared with the conventional device, and energy saving can be promoted.

[Brief description of drawings]

FIG. 1 is a block diagram of an exhaust gas recirculation type coating booth according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional coating booth. 11 …… Painting booth 12 …… Painting room 13 …… Conveyor 14 …… Painting object 15 …… Dusting zone 16 …… Front coating zone 17 …… Flash off zone 18 …… Post coating zone 19 …… Partition plate 19a ...... Communication passage 24a, 24b …… Air supply device 27a, 27b …… Exhaust device 28 …… Exhaust gas recirculation device 30 …… Solvent adsorber 31 …… Heating device 32 …… Circulation fan

Claims (2)

[Claims] 1. A coating booth having a pre-coating zone, a flash-off zone for solvent evaporation, and a post-coating zone in this order in the conveying direction of the article to be coated, wherein the coating booth has a U-turn structure and a U-turn section. And a front coating zone and a rear coating zone are adjacent to each other, and an exhaust gas recirculation device for circulating exhaust gas from the flash off zone to the flash off zone is provided in the flash off zone. In addition to communicating the pre-painting zone and the post-painting zone through the flash-off zone, the pre-painting zone and the post-painting zone are directly communicated with each other through a communicating passage formed in a partition plate between the pre-painting zone and the post-painting zone. Exhaust gas recirculation paint booth. 2. The exhaust gas recirculation type coating booth according to claim 1, wherein the exhaust gas recirculation device is provided with a solvent adsorber and a heater.