WO2013061411A1

WO2013061411A1 - Coating dryer

Info

Publication number: WO2013061411A1
Application number: PCT/JP2011/074592
Authority: WO
Inventors: 繁中島; 朝一石田
Original assignee: 新東工業株式会社
Priority date: 2011-10-25
Filing date: 2011-10-25
Publication date: 2013-05-02
Also published as: CN203908246U; IN2014CN03114A

Abstract

A coating dryer (1) is provided with: a conveyance means (10) for conveying a coated object (W); and a drying furnace (20) provided with a loading opening (20A) and an unloading opening (20B) which are provided for the coated object (W) which is being conveyed by the conveyance means (10), the drying furnace (20) comprising therein a conveyance route (10A) for the conveyance means (10). The drying furnace (20) comprises therein: a drying route (21) in which the flow of drying air flowing along the conveyance route (10A) is formed; and a drying air supply flow path (23) for supplying drying air to the drying route (21) from discharge openings (22) arranged in the vicinity of both the loading opening (20A) and the unloading opening (20B). A drying air circulation means (30) discharges a portion of air sucked in from a suction opening (31A) provided at the intermediate position of the drying route (21) and recirculates the portion of air to the drying air supply flow path (23).

Description

Paint drying equipment

The present invention relates to a coating drying apparatus for drying an object to be coated while being conveyed in a drying furnace.

Generally, for drying an object to be coated, a coating drying apparatus is used in which a conveying means is provided in a drying furnace and the object to be coated is dried while being conveyed. In particular, in a steel processing line for shipbuilding, after steel material is shot and polished, the steel material is coated, transported into a drying furnace, and dried while being transported.

As such a coating and drying apparatus, a hot air circulation type in which hot air is blown onto an object to be coated in a drying furnace is employed. The hot air circulation type coating drying apparatus described in the following Patent Document 1 branches from the heating section to the drying furnace, and has a heated air pipe that is open at two or more locations in the drying furnace. The hot air is blown toward the transport path in the drying furnace by the heated air pipe.

Japanese Patent Laid-Open No. 7-190620

Such a coating drying apparatus is required to be able to dry in a short time with hot air at the lowest possible temperature in order to increase the processing speed at low cost. On the other hand, the conventional paint drying apparatus is liable to cause a temperature drop while hot air flows through the heated air pipe, and must be supplied with high-temperature hot air in advance. There was a problem that the costly drying process could not be performed.

In addition, since the conventional paint drying apparatus is a type in which heated air is blown into the drying furnace by a blower fan, the inside of the drying furnace is pressurized and the vaporization temperature of the paint is increased, and the temperature of the heated air is increased. When it is lowered, there is a problem that an efficient drying process cannot be performed. Furthermore, since it is a form in which hot air is blown toward the object to be coated, when drying processing is carried out while conveying the object to be coated, the time for direct contact with heated air is shortened, which also makes efficient drying processing. There was a problem that could not be done.

The present invention is an example of a problem to deal with such a problem. That is, in a coating and drying apparatus that dries an object to be coated while being transported in a drying furnace, the drying process can be performed in a short time using relatively low temperature dry air, and an efficient drying process is performed at a low cost. It is an object of the present invention to be able to do so.

In order to achieve such an object, a paint drying apparatus according to the present invention has at least the following configuration.
A transporting means for transporting the object to be coated; and a drying furnace provided with an inlet and an outlet for the object to be coated transported by the transporting means and having a transporting path for the transporting means provided therein. A drying processing path that forms a flow of drying air along the transport path, and a drying air supply channel that supplies the drying air to the drying processing path from a blow-out port that is disposed in the vicinity of the carry-in port and the carry-out port, respectively. And a drying air circulating means for exhausting a part of the air sucked from an intake port provided at an intermediate position of the drying processing path and circulating it to the drying air supply flow path. .

The coating drying apparatus having such a feature can make the inside of the drying treatment path for carrying out the drying treatment while conveying the object to be coated, so that the vaporization temperature of the organic solvent contained in the paint is lowered and the drying air is reduced. The drying speed can be increased even when the temperature of the is lowered. This enables an efficient drying process at a low cost. Further, since the inside of the drying treatment path is in a negative pressure state and the exhaust port is concentrated at one place of the dry air circulation means, it is possible to prevent the odor of the organic solvent generated during drying from being diffused to the surroundings.

Since a flow of dry air along the transport path is formed in the drying processing path, the object to be transported is always exposed to the flow of dry air, thereby enabling efficient drying. Since the dry air supply flow path is provided inside the drying furnace, a decrease in the temperature of the dry air up to the inside of the drying processing path can be suppressed. This also enables a heat-efficient drying process.

It is explanatory drawing which showed the whole structure of the coating drying apparatus which concerns on one Embodiment of this invention. FIG. 2A is a cross-sectional view of a drying furnace in a paint drying apparatus according to an embodiment of the present invention (FIG. 2A is a cross-sectional view along AA in FIG. 1, and FIG. 2B is a cross-sectional view along BB in FIG. 1). . It is explanatory drawing which showed the dry air circulation path | route of the coating drying apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment of the present invention includes the contents shown in the drawings, but is not limited thereto. FIG. 1 is an explanatory view showing the overall configuration of a coating drying apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view of a drying furnace in the coating drying apparatus according to an embodiment of the present invention (FIG. 2 (a). ) Is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line BB in FIG. FIG. 3 is an explanatory view showing a dry air circulation path of the paint drying apparatus according to the embodiment of the present invention.

A coating and drying apparatus 1 according to an embodiment of the present invention includes a conveying means 10 for conveying an object to be coated W such as a coated steel material, a drying furnace 20 for drying the object to be coated W, and dry air in the drying furnace 20. A dry air circulation means 30 for circulation is provided. In addition, in the following description, although the example used for the drying process in a part of shipbuilding steel processing line is illustrated and demonstrated, the to-be-coated object W is not specifically limited to this.

The transport means 10 is means for transporting the workpiece W coated in the previous coating process into the drying furnace 20 and delivering it to the next process through the drying furnace 20. In the illustrated example, a slat conveyor is used. Since the slat conveyor can be transported in a state where the bottom surface of the workpiece W is point-supported, the influence on the coating can be minimized. The conveying means 10 is not limited to this, and it is possible to use a roller conveyor, a hanger conveyor, a carriage (carriage) on which the object is placed and moved, depending on the state of painting and the form of the object. it can.

The drying furnace 20 includes a carry-in port 20A and a carry-out port 20B for the article W to be transported by the transport unit 10, and a transport path 10A for the transport unit 10 is provided therein. The drying furnace 20 supplies dry air to the drying processing path 21 from a drying processing path 21 that forms a flow of drying air along the transport path 10A, and an outlet 22 that is disposed in the vicinity of the carry-in port 20A and the carry-out port 20B. A dry air supply flow path 23 is provided inside. In the illustrated example, the air outlets 22 are provided both above and below the transport path 10 A in the transport unit 10.

In the illustrated example, the drying processing path 21 is a slit-shaped space formed between the internal ceiling surface 21A and the internal floor surface 21B in the drying furnace 20, and the internal ceiling surface 21A and the internal floor in the drying furnace 20 are illustrated. A dry air supply channel 23 is provided outside each of the surfaces 21B. Thus, the drying furnace 20 has a double ceiling and double floor structure by including the internal ceiling surface 21A and the internal floor surface 21B that form the drying processing path 21 inside the heat insulating outer wall 20S. Moreover, the double-wall structure is employ | adopted here also by providing the blower outlet 22 in the inner side of the heat insulation outer wall 20S in 20 A of carry-in ports, and the carry-out port 20B.

The dry air circulation means 30 partially exhausts the air sucked from the air inlet 31A provided at the intermediate position of the drying processing path 21 and circulates it to the dry air supply flow path 23. The inlet port 31A may be provided between the outlet port 22 on the carry-in port 20A side and the outlet port 22 on the carry-out port 20B side. However, the intake port 31A is effectively provided at a substantially central position in the longitudinal direction of the drying processing path 21. An air stream of dry air can be generated in the drying processing path 21.

The dry air circulation means 30 includes an intake passage 31, a circulation fan 32, an air supply passage 33, and an exhaust passage 34 that communicate with the drying processing path 21 at the intake port 31 A described above. The intake side of the circulation fan 32 is connected to the intake port 31A, and the air supply side of the circulation fan 32 is connected to the dry air supply flow path 23 via heating means 35 such as a gas burner unit. An exhaust port 34 A of the exhaust passage 34 is provided on the air supply side of the circulation fan 32. The heating means 35 can be deactivated or eliminated depending on the temperature of the outside air or the dry state.

The flow of the drying air of the paint drying apparatus 1 having such a configuration will be described. 1 to 3, the air flow is indicated by broken arrows. The circulation fan 32 sucks the processing air in the drying processing path 21 from the air inlet 31 A, so that an air flow along the transport path 10 A of the transporting unit 10 is generated in the drying processing path 21. The drying processing path 21 has a slit-like space so that such air flow is likely to occur, and the inside of the drying processing path 21 for performing the drying processing on the article W is an air circulation channel. It has become a part.

The air sucked out from the inside of the drying processing path 21 through the air inlet 31A is compressed by the circulation fan 32 and provided at both ends of the drying processing path 21 via the air supply passage 33 and the drying air supply passage 23. From the blowout port 22 into the drying processing path 21. The air blown out from the blowout port 22 is directed to the transport path 10A for transporting the workpiece W, and further forms an air flow toward the intake port 31A. By narrowing the space in the drying processing path 21 in a slit shape, this air flow can be accelerated.

In the drying treatment path 21 in which such an air flow is formed, the article W is always exposed to the flow of the dry air by the air flow along the transport path 10A, thereby improving the drying efficiency. be able to. In addition, since the air flow in the drying treatment path 21 is accelerated by the slit-shaped narrow space, the organic solvent of the paint can be efficiently vaporized.

Also, the air flow toward the intake port 31A causes the inside of the drying treatment path 21 to be in a negative pressure state centering on the central portion. This lowers the vaporization temperature of the organic solvent of the paint, and the paint can be dried in a short time without increasing the temperature of the drying air. For this reason, the fuel cost at the time of heating dry air can be held down, and the running cost at the time of operation can be reduced.

The organic solvent vaporized in the drying treatment path 21 is exhausted from the exhaust port 34 A through the exhaust passage 34 provided on the air supply side of the circulation fan 32. An exhaust fan 37 is provided in the exhaust passage 34. By providing the exhaust fan 37 on the air supply side of the circulation fan 32, the suction pressure of the circulation fan 32 becomes lower than the atmospheric pressure, and the negative pressure generated in the vicinity of the intake port 31A of the drying processing path 21 becomes more remarkable. Drying efficiency can be further increased. Depending on the amount of exhausted air, fresh air is sucked into the drying processing path 21 from the openings of the carry-in port 20A and the carry-out port 20B. The fresh air that has been sucked in is mixed with the circulating air blown from the blowout port 22 to become dry air having a high drying capacity, and this flows along the transport path 10A through the drying processing path 21.

In the illustrated example, the drying treatment path 21 of the drying furnace 20 is a narrow space sandwiched between the inner ceiling surface 21A and the inner floor surface 21B. As described above, this speeds up the flow of the drying air. . On the other hand, since the drying furnace 20 has a double ceiling and double floor structure in which the inner ceiling surface 21A and the inner floor surface 21B are covered by the heat insulating outer wall 20S of the drying furnace 20, a heat retaining effect in the drying treatment path 21 is thereby achieved. Can be increased. In addition, since the dry air supply flow path 23 is provided outside the internal ceiling surface 21A and the internal floor surface 21B in the double ceiling / double floor structure, the dry air is introduced while the dry air is guided into the drying processing path 21. It can suppress that temperature falls.

Moreover, by making the drying furnace 20 have a double ceiling and double floor structure, it is possible to suppress heat loss and drying odor (odor due to vaporization of organic solvent) in the drying furnace 20. In the illustrated example, the blowout port 22 is provided inside the heat insulating outer wall 20S of the drying furnace 20 at the carry-in entrance 20A and the carry-out exit 20B, so that the odor contained in the circulating air is outside the dry furnace 20. The leak is suppressed.

As shown in FIG. 3, the dry air circulation means 30 can be provided with a heating means 35 and an exhaust port 34 A on the air supply side of the circulation fan 32. As described above, the temperature of the drying air can be lowered by the negative pressure action in the drying processing path 21, so that the heating means 35 can be omitted or minimized, but when the outside air is low The drying capacity can be increased by raising the temperature of the drying air by the heating means 35.

At this time, the maximum drying efficiency can be obtained under each operating condition by changing the exhaust amount from the exhaust port 34A when the heating means 35 is operated and when it is not operated. In the example shown in FIG. 3, the heating unit 35 can be switched between operating and non-operating by the control unit 36, and the control unit 36 performs control to reduce the exhaust amount from the exhaust port 34 A when the heating unit 35 is operating. Do. The control for reducing the exhaust amount may be control for reducing the damper 34B of the exhaust port 34A or control for reducing the rotational speed of the exhaust fan 37.

When the temperature of the drying air is raised by operating the heating means 35, the exhaust temperature also rises. Therefore, the exhaust amount is limited within a range where the organic solvent concentration in the drying furnace 20 does not reach the dangerous concentration. . As a result, the waste heat loss accompanying the rise in the exhaust temperature can be minimized, the temperature in the drying processing path 21 can be raised to the maximum with a small amount of fuel used, and the heating means 35 is activated. The drying efficiency in the case can be improved. In addition, since the waste heat loss is reduced and the temperature in the drying processing path 21 can be increased in a short time, the preheating time can be shortened.

On the other hand, when the heating means 35 is deactivated, the control unit 35 controls the damper 34B and the exhaust fan 37 so that the exhaust amount is maximized. Increasing the amount of exhaust increases the amount of fresh air that enters the drying treatment path 21. As a result, the concentration of the vaporized organic solvent can be reduced, and the drying efficiency can be improved.

When the heating means 35 is operated, relatively high-temperature dry air is blown out from the blowout ports 22 provided at both ends of the drying processing path 21 and flows toward the intermediate intake port 31A, and the object W to be coated therebetween. dry. Air that has been used in the drying process and contains an organic solvent and has a reduced drying capacity is sucked from the intake port 31A and exhausted from the exhaust port 34A. According to this, since the air used for the drying process and having a reduced drying capacity is always exhausted, a drying process with high thermal efficiency becomes possible. Exhaust gas contains organic solvent odors, but the exhaust gas is limited to the exhaust port 34A and the openings such as the carry-in port 20A and the carry-out port 20B are in a negative pressure atmosphere. The odor leaking from the drying furnace 20 can be suppressed as much as possible.

Further, relatively cold air is sucked and heated at the intermediate portion of the drying processing path 21 and is supplied from both ends of the drying processing path 21, so that the temperature distribution in the drying processing path 21 is uniform along the longitudinal direction. Prone. As a result, the drying process can be performed efficiently over the entire area of the drying processing path 21 from the carry-in port 20A side to the carry-out port 20B side.

As shown in FIG. 3, the air compressed by the circulation fan 32 is heated by the heating means 35, branches to the upper surface side and the lower surface side of the drying processing path 21, and immediately enters the drying furnace 20, and then the drying furnace The air is branched left and right at the center of the dry air supply flow path 23 provided in the air 20 and sent to the blowout ports 22 provided at both ends of the dry processing path 21. Since the heat loss can be suppressed by arranging the dry air supply flow path 23 in the drying furnace 20, the duct volume of the dry air supply flow path 23 is set large so that the pressure loss is reduced. be able to.

Further, the dry air supply flow path 23 is provided inside the drying furnace 20 so as to be close to or in contact with the dry processing path 21, so that the heated dry air flowing through the dry air supply flow path 23 increases the temperature in the dry processing path 21. As a result, the heated and dried air can be routed through a long flow path without heat loss to the outside. Thereby, even when the drying process path 21 is designed to be long, it is possible to suppress a decrease in thermal efficiency.

When the coating drying apparatus 1 having such characteristics is provided in a shipbuilding steel processing line, a slat conveyor is used as the conveying means 10, and the blowout ports 23 are provided both above and below the conveying path 10A, so that the coating process can be performed. In the process of transporting the finished steel material along the transport path 10A, both the upper and lower surfaces can be dried simultaneously.

In conventional steel processing lines for shipbuilding, there is no other way to increase the line speed than to increase the drying distance, and there is a problem that efficient production with increased line speed is not possible at establishments where line space cannot be secured. It was. By using the paint drying apparatus 1 according to the embodiment of the present invention in a steel processing line for shipbuilding, it is possible to perform a drying process at a low cost and in a short time, and increase the line speed even at a relatively short drying distance. be able to. As a result, it is possible to increase the work efficiency in the drying process, which has conventionally been a bottleneck, and greatly improve the productivity of steel processing.

Claims

A transporting means for transporting the object to be coated, and a drying furnace provided with a transporting inlet and a transporting outlet for the object transported by the transporting means and provided with a transporting path for the transporting means inside,
The drying furnace supplies drying air to the drying processing path from a drying processing path that forms a flow of dry air along the transport path, and a blowout port that is disposed in the vicinity of the carry-in port and the carry-out port, respectively. With an air supply channel inside,
A coating drying apparatus comprising: a drying air circulating means for exhausting a part of air sucked from an air inlet provided at an intermediate position of the drying processing path and circulating the air to the drying air supply channel.
The drying treatment path is a slit-shaped space formed between the inner ceiling surface and the inner floor surface in the drying furnace, and is provided outside the inner ceiling surface and the inner floor surface in the drying furnace. The paint drying apparatus according to claim 1, wherein the dry air supply flow path is provided.
The dry air circulation means includes a circulation fan, an intake side of the circulation fan is connected to the intake port, and an air supply side of the circulation fan is connected to the dry air supply flow path via a heating means, The paint drying apparatus according to claim 1 or 2, wherein an exhaust port is provided on the air supply side of the circulation fan.
The paint drying apparatus according to claim 3, wherein the heating means can be switched between operation and non-operation, and the exhaust amount from the exhaust port is reduced when the heating means is operated.
The coating and drying apparatus according to claim 1, wherein the transport means is a slat conveyor, and the outlets are provided both above and below the transport path in the transport means.
6. The coating drying apparatus according to claim 5, wherein the outlet is provided inside the heat insulating outer wall of the drying furnace at the carry-in port and the carry-out port.