NOZZLE BOX FOR A DRYING DEVICE FOR DRYING BOARD-SHAPED MATERIALS

Abstract

A nozzle box (7, 7) is arranged in a drying device in a transverse direction relative to a board (8) to be dried by means of drying air in the drying device. The nozzle box (7, 7) has a tapered shape in at least one direction perpendicular to the direction of flow of the drying air in the nozzle box (7, 7) and a drying surface provided with nozzles (18) and facing the board (8), wherein the drying air streams out of a plurality of nozzles (18) arranged in rows in the drying surface onto the board (8). The nozzle box (7, 7) is characterized in that the ratio of the sum of the openings of the nozzles (18) per square meter to the drying surface is less than 1.1%.

Claims

1.-12. (canceled)

13. A nozzle box, wherein the nozzle box is arranged in a drying device in a transverse direction relative to a board to be dried by means of drying air in the drying device, has a tapered shape in at least one direction perpendicular to a direction of flow of the drying air in the nozzle box, and comprises a drying surface provided with nozzles and facing the board, the drying air streaming out of a plurality of nozzles arranged in rows in the drying surface onto the board, and a ratio of a sum of openings of the nozzles per square meter to the drying surface being less than 1.1%.

14. The nozzle box of claim 13, wherein an amount of recirculated air per square meter of drying surface is less than 0.13 m.sup.3/m.sup.2.

15. The nozzle box of claim 13, wherein the nozzles have openings with a diameter of less than 10 mm.

16. The nozzle box of claim 13, wherein a speed of the drying air exiting the nozzles is from 17 m/s to 21 m/s.

17. The nozzle box of claim 13, wherein the nozzles are spaced apart by more than 60 mm.

18. The nozzle box of claim 13, wherein the nozzles are arranged in three rows extending in a longitudinal direction of the nozzle box.

19. The nozzle box of claim 13, wherein the rows of nozzles are spaced apart by from 55 mm to 80 mm.

20. The nozzle box of claim 18, wherein the rows of nozzles are spaced apart by from 55 mm to 80 mm.

21. The nozzle box of claim 13, wherein the nozzle box has a tapered design in a vertical spatial direction only.

22. The nozzle box of claim 13, wherein the nozzle box further comprises a deflector plate on its respective longitudinal sides laterally from the nozzle rows in a direction of the board.

23. The nozzle box of claim 13, wherein a distance of the nozzles from the board is at least 22 mm.

24. The nozzle box of claim 13, wherein the nozzle box has a double-tapered shape.

25. The nozzle box of claim 15, wherein the nozzles are spaced apart by more than 60 mm.

26. The nozzle box of claim 15, wherein the nozzles are arranged in three rows extending in a longitudinal direction of the nozzle box.

27. The nozzle box of claim 15, wherein the rows of nozzles are spaced apart by from 55 mm to 80 mm.

28. The nozzle box of claim 25, wherein the nozzles are arranged in three rows extending in a longitudinal direction of the nozzle box.

29. The nozzle box of claim 25, wherein the rows of nozzles are spaced apart by from 55 mm to 80 mm.

30. The nozzle box of claim 28, wherein the rows of nozzles are spaced apart by from 55 mm to 80 mm.

31. The nozzle box of claim 15, wherein a distance of the nozzles from the board is at least 22 mm.

32. A drying device for drying boards which can be conveyed in decks through a drying chamber comprised by the drying device, wherein the boards in the drying device can be brought into contact with drying air produced in a ceiling unit and subsequently introduced into nozzle boxes via a pressure chamber for the purpose of drying and the drying air can be discharged via a vacuum chamber after absorbing moisture from the boards, the drying device comprising a plurality of nozzle boxes according to claim 13.

Description

[0028] In the following, the nozzle box in accordance with the invention is described further with the aid of an illustrative embodiment. The figures show:

[0029] FIG. 1 a longitudinal section of a drying device with a pressure chamber, a drying chamber and a vacuum chamber,

[0030] FIG. 2 a side view of two nozzle boxes according to FIG. 1, which are arranged on top of one another between respective boards to be dried,

[0031] FIG. 3 a top view of the side of a double-tapered nozzle box facing a board to be dried, and

[0032] FIG. 4 an isometric view of the end area of the nozzle box according to FIG. 2 which faces a vacuum chamber of the drying device.

[0033] Drying air, the direction of flow of which is indicated by arrows, flows in a drying device (FIG. 1) of a transversely ventilated gypsum-board cooler. Pre-heated fresh air is fed to a burner 1 as combustion air 2. The further conveyance of the air heated by the burner 1 into the pressure chamber 5 occurs via a recirculation fan 4. 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 from which it is blown perpendicularly onto gypsum boards 8 or other boards to be dried via hole nozzles arranged on the top or bottom side of the nozzle boxes. The boards 8 lie on supporting rollers and are conveyed by means of a transport installation (not described here further) in a direction perpendicular to the viewing plane of FIG. 1. The supporting rollers are arranged between and slightly above the nozzle boxes 7 so that the drying air streams between the supporting rollers onto the boards 8.

[0034] In order to ensure an optimal flow and introduction of the drying air from a ceiling unit 11 into the pressure chamber 5 and from the latter via the nozzle boxes 7 along the boards 8 into a vacuum chamber 9, the width of the pressure chamber 5 is greater than the width of the vacuum chamber 9. Guide plates 12, 13, 14 and 15 can be provided for guiding the air flow; an air-flow straightener 16 is further provided for the purpose of rendering the air flow even.

[0035] A part of the drying 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 10. The air flow circuit is completed at the burner 1.

[0036] Two nozzle boxes 7 (FIG. 2) are respectively arranged between two boards 7 to be dried. They are spaced apart from one another by an element 17 serving an attachment function on the side facing the vacuum chamber 9. FIG. 3 shows a double-tapered nozzle box 7, which, in contrast to the nozzle boxes 7, is also tapered on the side of the vacuum chamber 9 in the plane provided with nozzles 18 from which the air flows to the board 8 to be dried.

[0037] On the side respectively facing a board 8, each nozzle box 7 is provided with nozzles 18 respectively arranged in three rows from which the drying air flows to the respective board 8.

[0038] On the side facing the vacuum chamber 9, the nozzle boxes 7 comprise a slot 20 above and below an end plate 19 (FIG. 4), through which dirt can be removed from the nozzle box 7. Deflector plates 21 are additionally arranged on each longitudinal side of the surface of the nozzle boxes 7 facing the board 8 to be dried.