METHOD AND DEVICE FOR DRYING BOARDS

Abstract

In a method for drying boards, which are guided in decks through a drying device, wherein the boards (8) in the drying device are brought into contact with drying air by means of an impinging jet ventilation and wherein the impinging jet ventilation is ensured by means of transversely ventilated nozzle boxes (7), the drying air is supplied by means of at least two fans (4a, 4b) arranged next to one another in an airflow of the drying air produced by a burner (1), which guides the drying air to the fans (4a, 4b).

Claims

1-9. (canceled)

10. A method for drying boards, wherein the method comprises guiding the boards in decks through a drying device, bringing the boards in the drying device into contact with drying air by an impinging jet ventilation, the impinging jet ventilation being ensured by transversely ventilated nozzle boxes, and supplying the drying air by at least two fans arranged next to one another in an air flow of the drying air heated by a burner, which is arranged before the at least two fans in a direction of flow.

11. A drying device configured for use in the method of claim 10, wherein the drying device comprises a ceiling unit in which a burner produces drying air, the ceiling unit comprising at least two fans arranged next to one another which can be supplied with the drying air from the burner.

12. The drying device of claim 11, wherein each of the at least two fans comprises a direct drive.

13. The drying device of claim 11, wherein each of the at least two fans is enclosed by a volute housing.

14. The drying device of claim 13, wherein each of the at least two fans is enclosed by a volute housing.

15. The drying device of claim 11, wherein each of the at least two fans comprises a four-pole motor.

16. The drying device of claim 15, wherein each of the at least two fans comprises an asynchronous motor.

17. The drying device of claim 15, wherein the motor has a speed of 1500 revolutions per minute.

18. The drying device of claim 16, wherein the motor has a speed of 1500 revolutions per minute.

19. The drying device of claim 11, wherein each of the at least two fans comprises an outer impeller diameter of approximately 800 mm.

20. The drying device of claim 11, wherein a ratio of an intake height of the at least two fans, in relation to an outer impeller diameter, is at least 0.5.

21. The drying device of claim 11, wherein a ratio of an intake height of the at least two fans, in relation to an outer impeller diameter, is greater than 0.8.

22. The drying device of claim 19, wherein a ratio of an intake height of the at least two fans, in relation to the outer impeller diameter, is at least 0.5.

23. The drying device of claim 19, wherein a ratio of an intake height of the at least two fans, in relation to the outer impeller diameter, is greater than 0.8.

24. The drying device of claim 11, wherein a ratio of an outer impeller diameter of one of the at least two fans to a distance between an impeller outlet for drying air exiting the at least two fans and a wall of the ceiling unit above a pressure chamber is greater than 3.5.

25. The drying device of claim 19, wherein a ratio of an outer impeller diameter of one of the at least two fans to a distance between an impeller outlet for drying air exiting the at least two fans and a wall of the ceiling unit above a pressure chamber is greater than 3.5.

26. The drying device of claim 22, wherein a ratio of the outer impeller diameter of one of the at least two fans to a distance between an impeller outlet for drying air exiting the at least two fans and a wall of the ceiling unit above a pressure chamber is greater than 3.5.

27. The drying device of claim 11, wherein the at least two fans can be operated with opposite rotations.

28. The drying device of claim 12, wherein the at least two fans can be operated with opposite rotations.

29. The drying device of claim 15, wherein the at least two fans can be operated with opposite rotations.

Description

[0023] In the following, the device in accordance with the invention is described further with the aid of an illustrative embodiment. The figures show:

[0024] FIG. 1 a longitudinal section of a drying device and

[0025] FIG. 2 a level sectional view along a section line A-A shown in FIG. 1.

[0026] Drying air flows in a drying device (FIGS. 1, 2), the direction of flow of which is indicated by arrows. Pre-heated fresh air is fed to a burner 1 as combustion air. The further conveyance of the air heated by the burner 1 into a pressure chamber 5 occurs via recirculation fans 4a, 4b (FIG. 2). The pressure chamber 5 serves to distribute the air evenly into the individual decks of a drying chamber 6. In the process, the air is first pressed into nozzle boxes 7 (merely one of which is depicted illustratively in FIG. 1), from which it is blown perpendicularly onto gypsum boards 8 or other boards to be dried via hole nozzles 70 (only a few hole nozzles 70 are depicted illustratively in FIG. 1), which for the sake of clarity are only illustrated in the upper drying level of the drying chamber 6 and which are arranged on the top or bottom side of the nozzle boxes. The boards 8 lie on supports (not illustrated here), such as e.g. supporting rollers, and are conveyed by means of a transport installation (also not described here further) in a direction perpendicular to the viewing plane.

[0027] In order to ensure an even distribution of the air over the width, the nozzle boxes 7 are configured to be tapered in the direction of flow of the air. The air escaping from the nozzle boxes 7 via the hole nozzles 70 then flows above and below the boards 8 into a vacuum chamber 9. A part of the air, which in sum essentially corresponds to the combustion gases, the fresh air and the water vapour generated by the drying action, escapes via an exhaust-air outlet. The air flow circuit is completed at the burner 1. The section above the pressure chamber 5, the drying chamber 6 and the vacuum chamber is the ceiling unit 11, also referred to as the overhead unit.

[0028] The fans 4a, 4b arranged in the ceiling unit 11 are arranged next to one another at a distance from the burner 1 and separated from one another by a partition 40. Both fans 4a, 4b are respectively enclosed by a volute housing 41. Both fans 4a, 4b are preferably arranged eccentrically in the area between the partition 40 and an outer wall 42 or 43 of the ceiling unit 11, wherein they are mounted closer to the outer walls 42, 43 than to the partition 40. It has been shown that, this way, for reasons relating to fluid dynamics, a more even supply of the drying air into the pressure chamber 5 is achieved.

[0029] The ratio of the outer impeller diameter of each fan 4a, 4b to a distance d between a lateral impeller outlet of the air exiting the fans 4a and 4b and a wall 50 of the ceiling unit 11 above the pressure chamber 5 is greater than 3.5.

[0030] For guiding the drying air exiting the burner to the underside of the fans 4a, 4b, an air guiding profile 12 and a wall 13 are provided.