Continuous-flow drying installation and method for drying workpieces

Abstract

A continuous-flow drying installation for drying workpieces, in particular vehicle bodies, having a heating zone enclosed by a first housing, in which the workpieces can be heated to a temperature T1, and having a cooling zone enclosed by a second housing, in which the workpieces heated in the heating zone can be cooled to a temperature T2<T1. The cooling zone is arranged completely above the heating zone. The continuous-flow drying installation additionally has a conveying zone enclosed by a third housing, in which there is arranged a transfer unit with which the workpieces heated in the heating zone can be transferred from the heating zone to the cooling zone, and a separating device which separates the heating zone from the conveying zone in an at least substantially air-tight manner but allows the workpieces to pass.

Claims

1. A continuous-flow drying installation for drying workpieces, comprising: a heating zone enclosed by a first housing, in which workpieces can be heated to a first temperature; a cooling zone enclosed by a second housing, in which the workpieces heated in the heating zone can be cooled to a second temperature, the second temperature being less than the first temperature, wherein the cooling zone is arranged completely above the heating zone; a conveying zone enclosed by a third housing, in which there is arranged a transfer unit with which the workpieces heated in the heating zone can be transferred from the heating zone to the cooling zone; and a separating device which separates the heating zone from the cooling zone in an at least substantially air-tight manner but allows the workpieces to pass through.

2. The continuous-flow drying installation as claimed in claim 1, further comprising a first conveying device having a first conveying direction arranged in the heating zone and a second conveying device having a second conveying direction arranged in the cooling zone for conveying the workpieces through the heating zone and the cooling zone, respectively.

3. The continuous-flow drying installation as claimed in claim 1, further comprising a second separating device between the conveying zone and the cooling zone, wherein the second separating device separates the conveying zone from the cooling zone in an at least substantially air-tight manner but allows the workpieces to pass through.

4. The continuous-flow drying installation as claimed in claim 3, further comprising a third separating zone arranged at the entry to the heating zone, wherein the third separating device separates the heating zone from surroundings of the continuous-flow drying installation in an at least substantially air-tight manner but allows the workpieces to pass through.

5. The continuous-flow drying installation as claimed in claim 1, wherein the separating device is an air-curtain-generating device which is adapted to generate an air curtain during operation.

6. The continuous-flow drying installation as claimed in claim 5, further comprising an extraction device with which air can be extracted from the conveying zone, and wherein the air which can be extracted by means of the extraction device can be fed to at least one of a first or a third air-curtain-generating device via in each case a feed line.

7. The continuous-flow drying installation as claimed in claim 5, further comprising a plurality of extraction devices with which air can be extracted from the conveying zone, and a collecting channel in which the air extracted from the conveying zone can be combined and from which the extracted air can be fed to at least one of the first or the third air-curtain-generating device via in each case a feed line.

8. The continuous-flow drying installation as claimed in claim 7, wherein the in each case one feed line or the collecting channel has a conditioning unit with which the air fed at least to the first or the third air-curtain-generating device can be conditioned.

9. The continuous-flow drying installation as claimed in claim 5, further comprising a fan which is adapted to convey air into the conveying zone in order to counteract the formation of a low pressure therein.

10. The continuous-flow drying installation as claimed in claim 1, further comprising a rapid removal unit arranged between the heating zone and the conveying zone and/or between the conveying zone and the cooling zone, wherein the rapid removal unit removes the workpieces cyclically from the heating zone into the conveying zone and/or from the conveying zone into the cooling zone.

11. A method for drying workpieces comprising the following steps: a) conveying workpieces through a heating zone enclosed by a first housing, in which the workpieces are heated to a first temperature; b) passing the workpieces at an exit of the heating zone through a separating device and into a conveying zone enclosed by a third housing; c) conveying the workpieces heated in the heating zone in the conveying zone from the heating zone to a cooling zone arranged completely above the heating zone and enclosed by a second housing; and d) conveying the workpieces through the cooling zone and cooling the workpieces in the cooling zone to a second temperature, the second temperature being less than the first temperature.

12. The method as claimed in claim 11, wherein an extraction device extracts air from the conveying zone.

13. The method as claimed in claim 12, wherein the air extracted by means of the extraction device is fed to the separating device via a feed line.

14. The method as claimed in claim 11, wherein a plurality of extraction devices extract air from the conveying zone, and the extracted air is combined in a collecting channel and fed to the separating device via a feed line.

15. The method as claimed in claim 12, wherein a fan conveys air into the conveying zone in order to counteract the formation of a low pressure therein.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Exemplary embodiments of the invention are described in greater detail hereinbelow with reference to the drawings, in which:

[0050] FIG. 1 shows a continuous-flow drying installation according to the invention for drying vehicle bodies in a lateral section;

[0051] FIG. 2 shows a vertical section along line II-II through the continuous-flow drying installation shown in FIG. 1;

[0052] FIG. 3 shows a continuous-flow drying installation according to the invention according to a second exemplary embodiment in a lateral section, in which the cooling zone is arranged directly above the heating zone;

[0053] FIG. 4 shows a continuous-flow drying installation according to the invention according to a third exemplary embodiment in a lateral section, in which two conveying zones are provided and the cooling zone extends in the longitudinal direction to the heating zone;

[0054] FIG. 5 shows a continuous-flow drying installation according to the invention according to a third exemplary embodiment in a lateral section, in which two conveying zones are provided and the cooling zone partially covers the heating zone.

DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

[0055] While this invention is susceptible to embodiments in many different forms, there is described in detail herein, preferred embodiments of the invention with the understanding that the present disclosures are to be considered as exemplifications of the principles of the invention and are not intended to limit the broad aspects of the invention to the embodiments illustrated.

1. First Exemplary Embodiment

[0056] FIG. 1 shows a continuous-flow drying installation 10 according to the invention for drying workpieces 12. The continuous-flow drying installation 10 has a heating zone 16 enclosed by a first housing 14 and a cooling zone 20 enclosed by a second housing 18. The cooling zone 20 is arranged over the heating zone 16 with a distance d between the housing 18 of the cooling zone 20 and the housing 14 of the heating zone 16 and partially covers the heating zone 16. However, it is also conceivable that the cooling zone 20 covers the heating zone 16 completely. The distance d can in particular be between 1.9 m and 2.3 m, in order to permit sufficient access to the cooling zone 20 and the heating zone 16 for maintenance. The cooling zone 20 is shown shorter than the heating zone 16 in FIG. 1, but the cooling zone 20 and the heating zone 16 can be of the same length, or the cooling zone 20 can also be longer than the heating zone 16.

[0057] A conveying zone 22 enclosed by a third housing 21 is arranged after the heating zone 16 in the conveying direction F. In the conveying zone 22 there is arranged a transfer unit 24 which transfers the workpieces 12 from the level of the heating zone 16 to the level of the cooling zone 20.

[0058] At the entry into the heating zone 16 there is arranged a separating device 26, which separates the heating zone 16 from the surroundings of the continuous-flow drying position. Further separating devices 28, 30 are arranged at the entry and at the exit of the conveying zone 22. The separating devices 28, 30 prevent warm air from flowing out of the heating zone 16 into the cooling zone 20. The separating devices 26, 28, 30 comprise nozzles arranged in rows. During operation, air is blown out of the nozzles, or out of the nozzle, under high pressure in order to generate an air curtain, that is to say a substantially closed surface.

[0059] The continuous-flow drying installation 10 has extraction devices 32, 34 arranged at the housing 21 of the conveying zone 22. The extraction devices 32, 34 comprise regulating units 35, which regulate the extraction volume flow, and a common fan 37 arranged in the collecting line 44 for generating a low pressure. The regulating units 35 can be manually or electrically controlled valves. In the collecting line 44 there is additionally arranged a conditioning unit 46 with which the extracted air is purified and dehumidified. The conditioning unit 46 can additionally heat the extracted air. The conditioned extracted air can be fed to the separating devices 26, 28 via feed lines 38, 40. A fan 42 serves to convey fresh air into the conveying zone 22.

[0060] The workpieces 12 are conveyed by means of a conveying device 39 with a conveying direction F first through the separating device 26 at the entry of the heating zone 16 into the heating zone 16. There, the workpieces 12 are heated to a temperature T1, whereby the coatings of the workpieces 12 are cured. The workpieces 12 pass through a separating device 28 arranged at the exit of the heating zone 16 and thereby enter the conveying zone 22. The transfer unit 24 arranged in the conveying zone 22 bridges the different heights of the heating zone 16 and the cooling zone 20 by lifting the respective workpiece 22 from the entry of the conveying zone 22 to the exit of the conveying zone 22. A rapid removal unit 41 (not shown) removes the workpieces 12 from the conveying device of the heating zone 16 to the transfer unit 24.

[0061] The extraction devices 32, 34 extract the hot air flowing from the heating zone 16 and past the separating device 26, in order to reduce the condensation risk in the cooling zone 20. A low pressure is thereby generated in the conveying zone 22, whereby a pressure gradient is generated between the heating zone 16 and the conveying zone 22. This has the result that the warm air of the heating zone 16 flows into the conveying zone and into the cooling zone. In order to equalize the low pressure, the fan 42 conveys fresh air or ambient air (e.g. from a production hall) into the conveying zone 22.

[0062] The extracted warm air is used energy-efficiently in that the air is guided into a collecting channel 44 and is fed to the separating devices 26, 28. A conditioning unit 46 is provided for purifying, dehumidifying and warming the extracted air.

[0063] At the exit from the conveying zone 22, the respective workpiece 12 is conveyed by a conveying device 43 with a conveying direction G through the separating device 30 and thereby conveyed into the cooling zone 20. In the cooling zone 20, the temperature of the workpieces 12 is cooled to a temperature T2<T1, so that the workpieces 12 can be processed further after leaving the continuous-flow drying installation 10. A rapid removal unit 41 removes the workpieces 12 from the transfer unit 24 and deposits the workpieces 12 on the conveying device of the cooling zone 20.

[0064] FIG. 2 shows a cross-section of the conveying zone 22 shown in FIG. 1 along the section line II-II shown in FIG. 1. Three extraction devices 32, 34 extract air from the conveying zone 22. The two extraction devices 32 are arranged at the sides of the conveying zone 22, and the third extraction device 34 is arranged on the upper side of the conveying zone 22.

2. Second Exemplary Embodiment

[0065] FIG. 3 shows the continuous-flow drying installation 10 substantially shown in FIG. 1 but, unlike in FIG. 1, the cooling zone 20 is arranged over the heating zone 16 without a distance, so that the housing 14 of the heating zone 16 and the housing 18 of the cooling zone 20 immediately adjoin one another. The overall height of the continuous-flow drying installation 10 is thereby reduced as compared with the continuous-flow drying installation 10 of FIG. 1.

3. Third Exemplary Embodiment

[0066] FIG. 4 shows the heating zone 16, cooling zone 20 and conveying zone 22 shown in FIG. 1. In addition, a further conveying zone 48 enclosed by a housing 25 is arranged before the heating zone 16 in the conveying direction F. A transfer unit 24 is likewise arranged in the further conveying zone 48. The workpieces 12 are fed to the further conveying zone 48 at a height which is the same as the height of the cooling zone 20. The feed of workpieces 12 into the continuous-flow drying installation 10 and the removal of the workpieces 12 from the continuous-flow drying installation 10 are thus located at one height. The different levels of the workpiece feed and the heating zone 16 are bridged by means of the transfer unit 24 by lowering the workpieces 12.

[0067] By means of such an arrangement of the heating zone 16 and the cooling zone 20, the floor area of the continuous-flow drying installation 10 that is used is small, while access to the heating zone 16 and the cooling zone 20 for maintenance purposes is facilitated as compared with the arrangements shown in FIGS. 1 and 3.

[0068] The arrangement of a further conveying zone 48 before the heating zone 16 has the advantage that a higher degree of separation of the continuous-flow drying installation 10 from the surroundings is effected, in order to reduce the penetration of particles and impurities into the heating zone 16 and in order to reduce heat losses from the heating zone 16.

4. Fourth Exemplary Embodiment

[0069] FIG. 5 shows the continuous-flow drying installation 10 having two conveying zones 22, 48 from FIG. 4. Unlike in FIG. 4, however, the feed direction of the workpieces 12 into the continuous-flow drying installation 10 is contrary to the conveying direction F. In addition, the conveying direction G of the workpieces 12 through the cooling zone 20 and the removal direction of the workpieces 12 from the continuous-flow drying installation 10 are likewise contrary to the conveying direction F.

[0070] The compactness of the continuous-flow drying installation 10 is thereby increased as compared with the continuous-flow drying installation 10 of FIG. 4.

[0071] While this invention is susceptible to embodiments in many different forms, there is described in detail herein, preferred embodiments of the invention with the understanding that the present disclosures are to be considered as exemplifications of the principles of the invention and are not intended to limit the broad aspects of the invention to the embodiments illustrated.