JP2005138037A - Method for ventilating drying oven for coating, and drying oven for coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drying oven for coating in which a treating apparatus can be small-sized while the excellent ventilation efficiency is kept. <P>SOLUTION: The subject ventilation method is applied for the drying oven 1 for coating in which a coated material W is dried with hot air by supplying the heated air into a plurality of drying zones 5 and 6 arranged along the transporting direction of the coated material W. The heated air from the outside of the oven is sent only to a blowing duct 12 provided in the 1st drying zone 5 where the evaporated quantity of a volatile component is relatively small. On the other hand, the air containing the evaporated volatile component is discharged to the outside of the oven only from a suction duct 24 provided in the 2nd drying zone 6 where the evaporated quantity of the volatile component is relatively large. The air discharged to the outside of the 2nd drying zone 6 is treated in a treating apparatus 27. A part of the heated air is shifted from the 1st drying zone 5 to the 2nd drying zone 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coating drying furnace for supplying heated gas into a plurality of drying zones to dry an object to be heated with hot air, and a ventilation method therefor.

  Usually, in automobile coating lines, undercoating furnaces such as sealer furnaces, intermediate coating furnaces, water research furnaces, topcoating furnaces, etc. that dry the coating film of undercoating along the conveyor line that conveys the automobile body that is the object to be coated A paint drying furnace is installed. This type of drying furnace is formed in a tunnel shape in which the entrance and exit of the automobile body are provided at both ends of the furnace body in order to heat and dry the coating film while the automobile body is conveyed by a conveyor. And in the furnace, from the inlet side to the outlet side, the wet paint film of the automobile body is quickly dried and the body is heated up to the set temperature, and the automobile body is heated and held at the set temperature. Holding zones are provided. Here, FIG. 3 shows an example of a conventional paint drying furnace 41.

  A conventional coating drying furnace 41 shown in FIG. 3 includes a temperature raising zone 42 at the front stage and a holding zone 43 at the rear stage. The temperature raising zone 42 is provided with a blowing duct 45 and a suction duct 47, and the holding zone 43 is provided with a blowing duct 46 and a suction duct 48. The blow-out ducts 45 and 46 are each provided with an air supply portion 49 for supplying heated air into the furnace, while the suction ducts 47 and 48 are supplied with gas containing evaporated volatile components (coating resin and solvent) outside the furnace. Exhaust portions 50 are provided for exhausting each. That is, the paint drying furnace 41 in FIG. 3 has two systems for supplying and exhausting air. Moreover, these exhaust parts 50 are finally introduced into the deodorizing apparatus 52 via the piping 51 which joins on the way. In addition, the structure similar to this is conventionally disclosed also in the following literature (for example, refer patent document 1).

Japanese Patent Laid-Open No. 11-28409 (FIG. 1 etc.)

However, in the above-described conventional paint drying furnace 41 having two supply / exhaust paths, if the heated air is supplied to each of the two air supply portions 49 by a predetermined amount (for example, 100 Nm ³ / min), the deodorizing device 52 supplies it. The combined amount (200 Nm ³ / min) of gas will be introduced. However, when the processing air volume introduced into the deodorizing device 52 becomes large, a large-scale deodorizing device 52 corresponding to the processing air volume is required, resulting in high equipment costs.

Therefore, as a measure for solving such a problem, it is conceivable to simply halve the amount of supply air supplied to the two supply units 49 (for example, 50 Nm ³ / min each). However, in this case, the ventilation efficiency in the furnace is deteriorated, and the coating film is not efficiently dried. As another measure, it can be considered that one of the two supply / exhaust paths is omitted. However, even if this measure is taken, air tends to stay in the drying zone where the air supply / exhaust path is omitted, as a result of no positive air supply / exhaust. Therefore, the ventilation efficiency in the furnace is deteriorated, and the coating film is not efficiently dried.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a paint drying furnace ventilation method and a paint drying furnace capable of downsizing a processing apparatus while maintaining suitable ventilation efficiency. There is to do.

  Then, when the present inventors conducted earnest research in order to solve the said subject, it paid attention to the difference in the amount of volatile component evaporation in several drying zones. If air is supplied only to the drying zone where the amount of volatile component evaporation is relatively small, while air is exhausted only from the drying zone where the amount of evaporation of volatile components is relatively large, the air supply is maintained while maintaining ventilation efficiency. The fact that the air volume and exhaust air volume can be reduced was newly found. Therefore, the inventors of the present application have further studied based on such knowledge, and finally came up with the following invention.

  That is, according to the first aspect of the present invention, a heated gas is supplied into a plurality of drying zones arranged along the conveying direction of the coating object to dry the coating object with hot air, and the gas containing evaporated volatile components In the ventilation method of the coating drying furnace in which the processing apparatus is used after discharging the gas outside the drying zone, only the blowout duct of the first drying zone having a relatively small amount of evaporation of volatile components is heated from outside the furnace. While supplying the gas, the gas containing the evaporated volatile component is discharged out of the furnace only from the suction duct of the second drying zone where the evaporation amount of the volatile component is relatively large. The gist of the method is a ventilation method for a paint drying furnace, in which a part is moved from the first drying zone to the second drying zone.

  Therefore, according to the ventilation method of claim 1, since air is supplied only to the blowout duct of one drying zone and exhaust is performed only from the suction duct of the other drying zone, In comparison, the supply air volume and the exhaust air volume are reduced. Therefore, the processing air volume introduced into the processing apparatus can be suppressed. In addition, since a part of the heated gas in the furnace is transferred from the first drying zone to the second drying zone, the gas does not stay in one of the drying zones, and suitable ventilation efficiency is maintained. In this case, the gas moving from the first drying zone to the second drying zone already contains evaporated volatile components, but the amount thereof is relatively small. Therefore, it can dry efficiently also in a 2nd drying zone using the said gas.

  As mentioned above, according to this ventilation method, a processing apparatus can be reduced in scale, maintaining suitable ventilation efficiency.

  A second aspect of the present invention is the first aspect, wherein a part of the blowing duct included in the first drying zone and a part of the suction duct included in the second drying zone are arranged to face each other. Is the gist.

  Therefore, according to the second aspect of the present invention, the heated gas can be smoothly transferred from the first drying zone to the second drying zone. In addition, at the boundary portion between the first drying zone and the second drying zone, an air seal is generated when the heated gas flows in a certain direction. Therefore, air leakage from the second drying zone to the first drying zone is unlikely to occur, and a reduction in ventilation efficiency due to air leakage is prevented in advance.

  The invention described in claim 3 is to supply heated gas into a plurality of drying zones arranged along the conveying direction of the object to be dried by hot air, and to remove evaporated volatile components. A first drying zone having a blow-out duct and a suction duct and having a relatively small amount of evaporation of volatile components, and a blow-out duct and a suction duct in a coating drying furnace that performs a predetermined treatment after exhausting the gas contained outside the drying zone A second drying zone having a relatively large amount of evaporation of volatile components, an air supply unit that is provided in a blow-off duct of the first drying zone, and that supplies heated gas from outside the furnace, and the second drying An exhaust part that is provided in a suction duct of the zone and exhausts gas containing evaporated volatile components to the outside of the furnace; a part of the blowing duct of the first drying zone; and the second drying zone. And air seal generator of the structure which is disposed to face a portion of the suction duct has found as its gist the paint drying furnace, characterized in that it comprises a connected deodorizing device in the exhaust.

  Therefore, according to the paint drying furnace of the third aspect, it is possible to supply air only to the blowout duct of the first drying zone through the air supply unit. Moreover, exhaust can be performed only from the suction duct of the second drying zone via the exhaust part. Furthermore, by arranging a part of the blowout duct and a part of the suction duct to face each other, the heated gas can be smoothly transferred from the first drying zone to the second drying zone. As described above, if this paint drying furnace is used, the above-described excellent ventilation method can be carried out easily and reliably.

  As described in detail above, according to the first and second aspects of the invention, it is possible to provide a ventilation method for a paint drying furnace capable of downsizing a processing apparatus while maintaining a suitable ventilation efficiency. . Moreover, according to invention of Claim 3, the coating-drying furnace provided with the structure suitable for implementing said ventilation method can be provided.

  Hereinafter, a paint drying furnace 1 according to an embodiment of the present invention and a ventilation method using the same will be described in detail with reference to FIG.

  As shown in FIG. 1, the paint drying furnace 1 of the present embodiment is a so-called mountain-shaped paint drying furnace installed in a painting line for hot-air drying of a coating film of an automobile body W that is an object to be coated. is there. The coating film is formed by applying a water-soluble paint. A furnace body 2 constituting the paint drying furnace 1 is in a tunnel shape, and includes an upward slope passage, a horizontal conveyance passage, and a downward slope passage. An inlet 3 and an outlet 4 are provided at both ends of the furnace body 2. The automobile body W is carried into the furnace body 2 from the inlet 3 and carried out from the outlet 4. A heating zone 5 (first drying zone) that heats and raises the vehicle body W carried in from the inlet 3 to 130 ° C. to 140 ° C. with hot air is disposed in the front stage of the horizontal transfer passage in the furnace body 2. . A holding zone 6 (second drying zone) that dries with hot air while holding the temperature of the vehicle body W that has been heated through the temperature raising zone 5 is disposed after the temperature raising zone 5 in the horizontal conveyance path. ing.

In the temperature raising zone 5, a blowing duct 12 having a plurality of outlets 11 for blowing hot air into the furnace and a suction duct 14 having a plurality of suction ports 13 for sucking heated air in the furnace are arranged to face each other. ing. Although FIG. 1 shows a state in which the blowout duct 12 and the suction duct 14 are arranged above and below across the conveyance path, the present invention is not limited to this, and they may be arranged on the left and right. The blowing duct 12 is provided with an air supply unit 15 for supplying heated air into the furnace. However, the suction duct 14 is not particularly provided with an exhaust part for discharging heated air to the outside of the furnace. The air supply unit 15 is connected to hot air supply means 16 that generates and sends hot air having a predetermined temperature. In the present embodiment, the amount of air supplied by the hot air supply means 16 is set to 110 Nm ³ / min.

A burner 17 and a fan 18 are provided on the circulation path connecting the suction duct 14 and the blowout duct 12 in the temperature raising zone 5. Therefore, after the air recirculated from the suction duct 14 is heated by the burner 17, it is pumped by the fan 18 and supplied again from the blowout duct 12 into the furnace. In the present embodiment, such an air circulation amount is set to 500 Nm ³ / min.

In the holding zone 6, a blowing duct 22 having a plurality of outlets 11 for blowing hot air into the furnace and a suction duct 24 having a plurality of suction ports 13 for sucking heated air in the furnace are arranged to face each other. Yes. Although FIG. 1 shows a state in which the blowout duct 22 and the suction duct 24 are arranged above and below across the conveyance path, the present invention is not limited to this, and they may be arranged on the left and right. The blowing duct 22 is not particularly provided with an air supply unit 15 for supplying heated air into the furnace. On the other hand, the suction duct 24 is provided with an exhaust part 25 for exhausting air containing evaporated volatile components to the outside of the furnace. One end of the passage 26 connected to the exhaust unit 25 is connected to a deodorizing device 27 (processing device). Further, an exhaust fan 28 for introducing contaminated air exhausted through the exhaust unit 25 to the deodorizing device 27 is disposed in the path 26. In the present embodiment, the amount of air exhausted through the passage 26 is set to 110 Nm ³ / min.

A burner 17 and a fan 18 are also provided on the circulation path connecting the suction duct 24 and the blowout duct 22 in the holding zone 6. Therefore, after the air recirculated from the suction duct 24 is heated by the burner 17, it is pumped by the fan 18 and supplied again from the blowout duct 22 into the furnace. In the present embodiment, such an air circulation amount is set to 500 Nm ³ / min.

In the case of the paint drying furnace 1 of the present embodiment, the suction duct 24 included in the holding zone 6 is formed slightly longer than the suction duct 22 included in the holding zone 6, and the front end portion extends to the temperature raising zone 5. . As a result, an air seal generating portion 31 having a structure in which the front end portion of the suction duct 24 and the rear end portion of the blowing duct 12 are arranged to face each other is configured. Therefore, at the boundary portion between the temperature raising zone 5 and the holding zone 6, the heated air flows in a certain direction (the direction from the bottom to the top in FIG. 1), so that an air seal is generated. In addition, a part of the heated air in the furnace is thereby transferred from the temperature raising zone 5 to the holding zone 6. In the present embodiment, the air transfer amount from the temperature raising zone 5 to the holding zone 6 is set to be 110 Nm ³ / min, which is equal to the supply amount and the exhaust amount. Such setting is achieved by appropriately adjusting the length (so-called offset length) of the portion where the suction duct 24 and the blowout duct 12 are arranged to face each other.

  Next, the ventilation method in the case of performing hot air drying using the coating drying furnace 1 of this embodiment is demonstrated.

  The hot air generated by the hot air supply means 16 reaches the blowing duct 12 of the temperature raising zone 5 through the supply unit 15 and blows out vigorously from the outlets 11 into the furnace. In the temperature raising zone 5, when the automobile body W is exposed to such hot air, volatile components such as an organic solvent and a coating film resin contained in the coating film evaporate to some extent. In the case of the present embodiment, the volatile component evaporation amount (indicated as HC evaporation amount in FIG. 1 and the like) in the temperature raising zone 5 was measured to be 13 g, and the concentration was measured to be 90 ppm.

  Most of the heated air in the temperature raising zone 5 is circulated through the circulation path of the temperature raising zone 5. However, some of them are sucked into the suction duct 24 of the holding zone 6 arranged in an offset state. At this time, an air seal is generated at the boundary between the temperature raising zone 5 and the holding zone 6 due to the movement of the heated air from the bottom to the top. The air seal separates the temperature raising zone 5 and the holding zone 6, so that the flow of heated air from the holding zone 6 having a large volatile component evaporation amount to the temperature raising zone 5 having a small volatile component evaporation amount is prevented. The

  Most of the heated air that has moved to the holding zone 6 is circulated through the circulation path of the holding zone 6. At this time, the heated air becomes hot air and blows out vigorously from the outlets 11 of the blowing duct 22 into the furnace. In the holding zone 6, when the automobile body W is exposed to such hot air, part of the volatile components contained in the coating film evaporates. In the case of the present embodiment, the amount of volatile component evaporation in the holding zone 6 was measured to be 130 g, and the concentration was measured to be 1000 ppm. In addition, although the volatile component which evaporated already is contained in the heating air which transfers to the holding zone 6 from the temperature rising zone 5, the quantity is comparatively small. Therefore, the coating film can be efficiently dried even in the holding zone 6 using the air. A part of the heated air in the holding zone 6 is exhausted through the exhaust unit 25 and then deodorized by the deodorizer 27.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) As described above, according to the ventilation method of the present embodiment, the supply air volume and the exhaust air volume are halved as compared with the conventional one, and therefore, the processing air volume introduced into the deodorizing device 27 is suppressed to about half of the conventional one. Can do. Further, since a part of the heated air in the furnace is transferred from the temperature raising zone 5 to the holding zone 6, the heated air does not stay in one of the drying zones, and a suitable ventilation efficiency is maintained. In this case, since the evaporation amount of the volatile component contained in the heated air moving from the temperature raising zone 5 to the holding zone 6 is relatively small, the heated air is used to efficiently dry the temperature raising zone 6 as well. be able to.

  As described above, according to the ventilation method of the present embodiment, it is possible to reduce the size of the deodorizing device 27 while maintaining a suitable ventilation efficiency. Therefore, the equipment cost can be suppressed and the cost can be reduced. Of course, even in the present embodiment, the same level of drying as that of the prior art can be achieved.

  (2) Further, according to the present embodiment, the air supply amount can be reduced to about half of the conventional amount, so that the hot air supply means 16 can also be reduced in size, and the equipment cost can be suppressed by this. Moreover, since the fuel cost can be reduced by downsizing the hot air supply means 16, the running cost can be suppressed.

  (3) In this embodiment, a part of the blowing duct 12 included in the temperature raising zone 5 and a part of the suction duct 24 included in the holding zone 6 are disposed to face each other. Can be migrated without excess or deficiency. In addition, at the boundary portion between the temperature raising zone 5 and the holding zone 6 (that is, the air seal generating portion 31), the heated air flows in a certain direction, thereby generating an air seal. Therefore, air leakage from the temperature raising zone 5 to the holding zone 6 is less likely to occur, and a reduction in ventilation efficiency due to air leakage can be prevented in advance.

  (4) Moreover, if the coating drying furnace 1 having the structure shown in FIG. 1 is used, the excellent ventilation method of the present embodiment can be easily and reliably implemented.

  In addition, you may change embodiment of this invention as follows.

  For example, in the paint drying furnace 1 of another embodiment shown in FIG. 2, two systems of supply / exhaust paths are provided as in the conventional paint drying furnace 41 shown in FIG. That is, an air supply portion 15 is formed in each of the blowout ducts 12 and 22, and an exhaust portion 25 is formed in each of the suction ducts 14 and 24. However, on-off valves 32, 33, 34, and 35 are provided corresponding to the air supply unit 15 and the exhaust unit 25, respectively. Therefore, if the on-off valves 32 and 35 are opened while the on-off valves 33 and 34 are closed, the air supply / exhaust path becomes only one system, and ventilation similar to that in the above embodiment can be realized.

  -In the said embodiment, although this invention was applied to the coating drying furnace 1 which has two drying zones, it is not limited to this, You may apply to the coating drying furnace which has three or more drying zones. .

  -In the said embodiment, although this invention was applied to the mountain furnace, you may apply to a flat furnace, for example.

  In the embodiment described above, the automobile body W is the object to be coated. However, a work other than the automobile body W may naturally be the object to be coated.

  -The fluid is not limited to air, but may be other gas (such as nitrogen, argon or other reactive gas).

  The coating drying furnace 1 of the present invention can be embodied as an undercoating furnace such as a sealer furnace for drying a coating film of an undercoating, an intermediate coating furnace, an overcoating furnace, or the like.

  In the above-described embodiment, a specific example of drying a coating film formed of a water-soluble type paint has been described, but it is needless to say that a coating film formed of a solvent-type coating may be dried. However, in this case, the volatile component evaporation amount in the holding zone is relatively smaller than the volatile component evaporation amount in the temperature raising zone. Therefore, heated air is supplied from the outside of the furnace only to the blowing duct of the holding zone (first drying zone) in which the volatile component evaporation amount is relatively small. On the other hand, the gas containing the evaporated volatile component is discharged out of the furnace only from the suction duct of the temperature rising zone (second drying zone) having a relatively large amount of volatile component evaporation.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the embodiment described above are listed below.

  (1) When a part of the blowing duct included in the first drying zone and a part of the suction duct included in the second drying zone are arranged to face each other, the second drying is performed from the first drying zone. 3. The paint drying furnace according to claim 2, wherein an air volume to be transferred to the zone is set to be substantially equal to an air volume supplied from outside the furnace only to the blowing duct of the first drying zone. Ventilation method. Therefore, according to this, heating gas can be transferred without excess and deficiency.

1 is a schematic diagram showing a paint drying furnace according to an embodiment of the present invention. Schematic which shows the coating-drying furnace of another embodiment. Schematic which shows the conventional coating drying furnace.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Paint drying furnace 5 ... Temperature rising zone as 1st drying zone 6 ... Holding zone as 2nd drying zone 12, 22 ... Outlet duct 14, 24 ... Suction duct 15 ... Air supply part 25 ... Exhaust part 27 ... Processing Deodorizing device 31 as device 31. Air seal generating portion W ... Automobile body as object to be coated

Claims (3)

A heated gas is supplied into a plurality of drying zones arranged along the conveying direction of the coating object to dry the coating object with hot air, and the gas containing evaporated volatile components is discharged out of the drying zone. In the ventilation method of the paint drying furnace to be processed later using the processing equipment,
While supplying heated gas from the outside of the furnace only to the blowout duct of the first drying zone having a relatively small amount of volatile component evaporation, the suction of the second drying zone having a relatively large amount of volatile component evaporation The gas containing evaporated volatile components is exhausted from the duct only from the duct, and part of the heated gas in the furnace is transferred from the first drying zone to the second drying zone. How to ventilate the paint drying furnace.   2. The paint drying furnace according to claim 1, wherein a part of the blowing duct included in the first drying zone and a part of the suction duct included in the second drying zone are arranged to face each other. Ventilation method. A heated gas is supplied into a plurality of drying zones arranged along the conveying direction of the coating object to dry the coating object with hot air, and the gas containing evaporated volatile components is discharged out of the drying zone. In a coating and drying furnace that performs a predetermined treatment later,
A first drying zone having a blow-out duct and a suction duct and having a relatively small amount of volatile component evaporation;
A second drying zone having a blow-out duct and a suction duct and having a relatively large amount of evaporation of volatile components;
An air supply unit that is provided in a blow-out duct of the first drying zone and supplies heated gas from outside the furnace;
An exhaust part that is provided in a suction duct of the second drying zone and discharges gas containing evaporated volatile components to the outside of the furnace;
An air seal generating part having a structure in which a part of the blowing duct of the first drying zone and a part of the suction duct of the second drying zone are arranged to face each other;
A coating and drying furnace comprising a deodorizing device connected to the exhaust unit.

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