Drying device

Abstract

A drying device for drying coated, elongated work pieces in a continuous process including a transport device for transporting the work piece. For drying an edge or surface of the work piece, heat sources are arranged in a drying chamber. In a drying zone, drying vapor is generated during drying. The vapor is removed by an airflow. The airflow is supplied via a supply channel and fans. A controller is provided to control the fans.

Claims

1. A drying device for drying coated, elongated workpieces in a continuous process, comprising: a transport device for a continuous transport of a workpiece, a heat source for generating drying heat in a drying zone, an airflow generator for removing drying vapor from or supplying humidity to the drying zone via an airflow, a controller for controlling a quantity of air supplied to or discharged from the drying zone by the airflow generator, and a humidity sensor connected with the controller.

2. The drying device of claim 1, wherein the drying zone is arranged in a drying chamber and a part of the workpiece that is to be dried protrudes into the drying chamber.

3. The drying device of claim 2, wherein the drying chamber is substantially U-shaped in cross section.

4. The drying device of claim 2, wherein the drying chamber has a slot-like opening extending in a transport direction and the part of the workpiece that is to be dried protrudes through the slot-like opening.

5. The drying device of claim 4, wherein a chamber wall comprising the slot-shaped opening comprises thermal insulation plates.

6. The drying device of claim 4, wherein the slot-shaped opening has a height that is slightly larger than a thickness of the workpiece, with the height being less than 10 mm larger than the thickness.

7. The drying device of claim 1, wherein the airflow generator comprises at least one fan connected with the controller for rotational speed control.

8. The drying device of claim 1, wherein the airflow generator comprises or is connected with a supply channel or a discharge channel for supplying or discharging air or drying vapor.

9. The drying device of claim 8, wherein a throttle for adjusting the quantity of air supplied to the drying zone is arranged in an outlet opening of the supply channel or a throttle for adjusting the quantity of air or vapor discharged from the drying zone is arranged in an inlet opening of the discharge channel.

10. The drying device of claim 9, wherein the throttle of the supply channel or the throttle of the discharge channel is connected with the controller to adjust the quantity of air or vapor supplied to or discharged from the drying zone.

11. The drying device of claim 2, wherein the heat source is arranged in the drying chamber.

12. The drying device of claim 1, wherein the heat source comprises an infrared lamp.

13. The drying device of claim 7, wherein a quantity of air supplied or discharged is controlled via the rotational speed of the fans or at least one throttle such that a complete drying of the coating is achieved.

14. The drying device of claim 1, wherein the humidity sensor is configured to measure humidity in the drying zone or the discharged air from the drying zone and communicate the measured humidity to the controller to control the air quantity supplied to or discharged from the drying zone.

15. The drying device of claim 1, further comprising an air humidifier.

16. The drying device of claim 2, wherein the transport device is arranged entirely outside the drying chamber.

17. The drying device of claim 11, wherein the heat source is arranged opposite a part of the workpiece that is to be dried or extends in a transport direction of the workpiece.

18. The drying device of claim 14, wherein the humidity sensor is provided in the drying zone.

19. The drying device of claim 15, wherein the air humidifier is provided in a supply channel for supplying air or drying vapor.

20. The drying device of claim 15, wherein the air humidifier is connected with the controller.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 shows a schematic sectional view of an embodiment of a drying device according to the invention.

DESCRIPTION OF THE INVENTION

(2) For drying coated elongated work pieces in a continuous process, a drying device comprises a transport device schematically indicated in the embodiment illustrated by two transport rollers 10. An elongated work piece 12, such as a board for example, is arranged between the two transport rollers 10 and is transported by the transport rollers 10 perpendicularly to the drawing plane in the direction of an arrow 14. In the embodiment illustrated, for example an edge 16 of the workpiece 12 has been coated with lacquer, paint or the like in the coating device arranged upstream of the drying device. For drying, a heat source, in particular one or a plurality of infrared lamps 18, is provided. In the embodiment illustrated these are arranged in parallel with the coated edge or lateral surface 16 of the work piece 12. The heat source 18 is arranged in a housing 20 of the drying device. In the embodiment illustrated, the latter has a U-shaped cross section, with the surface 16 to be dried protruding into the housing 20.

(3) Due to the drying heat, drying vapor is generated in a drying zone 22 by the drying of the lacquer or the paint. In this embodiment air is supplied to the drying zone 22 via a supply channel 24 in the direction of an arrow 26 in order to discharge the drying vapor. The supply channel, which also extends in the longitudinal direction or the transport direction 14, comprises one or a plurality of airflow generating means such as fans 28. For the purpose of controlling the quantity of air supplied to the drying zone 22, the at least one fan 28 is connected with a control means 30. Further, a heat source 32 may be provided in the supply channel 24 for pre-heating the air supplied, the heat source preferably also being controllable via the control means.

(4) Further, a throttle means 36 may be provided in the region of an outlet opening 34 of the supply channel 24. In the embodiment illustrated the same is shown as a throttle flap pivotable in the direction of an arrow 36. By providing the throttle flap 36, it is not only possible to throttle the quantity of air supplied, but also to deflect the same. The position of the throttle flap may preferably also be controlled by means of the control means.

(5) In the embodiment illustrated a discharge channel 40 is provided opposite the supply channel 40. The discharge channel 40 is structured in a manner similar to the supply channel 24 and also comprises an airflow generating means with, for example, a plurality of fans 42 to draw air from the drying zone 22 in the direction of an arrow 44. The plurality of fans 42 are also connected with the control means 30 to be controlled thereby.

(6) Further, a throttle means 48, such as a throttle flap, may also be provided in the region of an inlet opening 46 of the discharge channel 40, the throttle flap being pivotable in the direction of an arrow 50. The position of the throttle flap 40 may also be controlled by means of the control means 30.

(7) It is further preferred to provide a humidity sensor 52 in the drying zone 22. Again, the same is connected with the control means 30.

(8) Further, in a particularly preferred embodiment, an air humidification means 54 is provided in the supply channel 24. The former is preferably connected with the control means 30. Thereby, it can be prevented that the upper layer of a lacquer dries too fast. Film formation is thus avoided, so that the water from the lacquer is dried as the lacquer layer is dried.

(9) A chamber wall 56 directed towards the transport device 10 that in particular comprises a plurality of belts and rollers, is preferably made of a thermal insulation plate. Thereby, it is ensured that the heat radiation emitted by the heat source 18, which is in particular designed as an IR lamp, does not or only to a small extent heat the transport device 10. This avoids damage to the transport device 10. The two chamber walls or thermal insulation plates 56 also extend in the longitudinal direction 14 and serve as a screen. The two chamber walls 56 form an opening 58. The opening 58 has a height H that corresponds to the distance between the two chamber walls 56. The height H is slightly larger than the thickness d of the elongated workpiece d. Thus, only a small gap is formed between the opening 58 and the work piece 12.

(10) In another preferred development of the invention a plurality of drying means is arranged one behind the other, in particular drying means corresponding to the above described different embodiments and, as is particularly preferred, corresponding to the embodiment illustrated in FIG. 1. It is possible for each drying means to adjust or control the individual parameters differently by means of a corresponding control means. In this regard it is of course possible to provide a common control device for the individual drying devices, so as to adjust them to each other.