Continuous dryer heat exchanger device

Abstract

A continuous dryer heat exchanger device has a plurality of heat exchanger units. Waste air of an associated dryer section of the associated continuous dryer is guided through an individual heat exchanger unit and contaminants from the waste air are deposited in the heat exchanger unit. A cleaning device for cleaning the continuous flow heat exchanger device of the contaminants is thereby provided, which cleaning device has a plurality of cleaning units. An associated heat exchanger unit is to be cleaned by means of the individual cleaning unit. A switching device is provided, by means of which the cleaning units are to be switched in series one after the other.

Claims

1. A continuous dryer heat exchanger device (30) comprising a plurality of heat exchanger units (32), wherein waste air (20) of an associated dryer section (16) of an associated continuous dryer (10) is guided through an individual heat exchanger unit (32) of the plurality of heat exchanger units (32) and wherein contaminants from the waste air (20) are deposited in the individual heat exchanger unit (32); and a cleaning device (50) for cleaning the continuous dryer heat exchanger device (30) of the contaminants, wherein the cleaning device (50) has a plurality of cleaning units (52), wherein an associated heat exchanger unit (32) is to be cleaned by an individual cleaning unit (52) of the plurality of cleaning units (52), and wherein a switching device (82) is provided, by which the plurality of cleaning units (52) are to be switched in series one after another.

2. The continuous dryer heat exchanger device according to claim 1, wherein the waste air (20) flows in a U-shape through the individual heat exchanger unit (32).

3. The continuous dryer heat exchanger device according to claim 1, wherein the waste air (20) flows in a U-shape through the individual heat exchanger unit (32), first in an ascending manner and then in a descending manner.

4. The continuous dryer heat exchanger device according to claim 1, wherein at least one cleaning unit (52) of the plurality of cleaning units (52) is configured with at least one washing nozzle (58) for supplying a washing liquid into the associated heat exchanger unit (32).

5. The continuous dryer heat exchanger device according to claim 4, wherein the at least one washing nozzle (58) is movably arranged in a lower region (38) of the associated heat exchanger unit (32).

6. The continuous dryer heat exchanger device according to claim 4, wherein the at least one washing nozzle (58) is fixedly arranged in an upper region (42) of the associated heat exchanger unit (32).

7. The continuous dryer heat exchanger device according to claim 4, wherein a separating device (66) for separating the contaminants from the washing liquid is provided.

8. The continuous dryer heat exchanger device according to claim 7, wherein the separating device is configured with an endless belt filter (78).

9. The continuous dryer heat exchanger device according to claim 7, wherein a return device (80) for returning separated contaminants back into an associated continuous dryer (10) is provided.

10. The continuous dryer heat exchanger device according to claim 4, wherein a lye-adding device (72) for adding a lye to the washing liquid is provided.

11. The continuous dryer heat exchanger device according to claim 4, wherein a biocide-adding device (74) for adding a biocide to the washing liquid is provided.

12. The continuous dryer heat exchanger device according to claim 4, wherein a dispersant-adding device (74) for adding a dispersant to the washing liquid is provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a perspective view of a continuous dryer on which an exemplary embodiment of a continuous dryer heat exchanger device according to the invention is mounted.

[0020] FIG. 2 shows section II-II according to FIG. 1 through in particular one heat exchanger unit.

[0021] FIG. 3 is a perspective view of a cleaning device for supplying a washing liquid, mounted in a lower region of an associated heat exchanger unit according to FIG. 2.

[0022] FIG. 4 is a perspective view of a cleaning device for supplying a washing liquid, mounted in an upper region of an associated heat exchanger unit according to FIG. 2.

[0023] FIG. 5 is a perspective view of a separating device for separating contaminants from the washing liquid.

DETAILED DESCRIPTION

[0024] FIGS. 1 and 2 show a continuous dryer 10 which is used for drying a material to be dried (not shown), in the present case a bulk material in the form of wood chips, sawdust, RDF, etc. The material is in the form of a layer on a revolving transport belt 12, wherein it is applied to the transport belt 12 at a material feed 14, then passes on the transport belt 12 through a plurality of dryer sections 16 and finally is removed from the transport belt 12 again at a material delivery 18.

[0025] For drying, drying air is guided through the material to be dried and the transport belt located beneath it, which drying air is discharged in the lower region as recirculating air or waste air 20 from the dryer sections 16 located at the rear in the transport direction and is then returned to the upper region of those dryer sections 16 as return air 22 by means of a circulating-air guide 24. At the same time, fresh air 26 is supplied by means of an air supply 28 to the upper region of dryer sections 16 located at the front in the transport direction. This fresh air 26 thereby flows through a continuous dryer heat exchanger device 30, through which the waste air 20 is guided at the same time. Heat energy of the waste air 20 is thereby returned to the fresh air 26, wherein at the same time moisture from the material that has accumulated in the waste air 20 is condensed out.

[0026] The continuous dryer heat exchanger device 30 is configured with a plurality of heat exchanger units 32, which individually have a housing 34 which is largely separate in terms of flow and is connected to a waste air channel 36 for the waste air 20. The waste air 20 thereby passes from the waste air channel 36 in a lower housing region 38 into the housing 34 and into an ascending, in particular vertical housing region 40 located therein. In an upper housing region 42 located downstream in the flow direction, the waste air 20 is then further diverted in a U-shape into a descending housing region 44, which is likewise in particular vertical, until it finally passes in the lower housing region 38 as return air 22 into a circulating-air supply channel or return air channel 46 again. At the same time, a fresh air channel 48 is formed by means of heat exchanger surfaces (not shown in detail) transversely and in particular horizontally through the ascending housing region 40 and the descending housing region 44, through which fresh air channel fresh air 26 is supplied as explained above.

[0027] A cleaning device 50 for cleaning in particular the mentioned heat exchanger surfaces is provided on the continuous dryer heat exchanger device 30, which cleaning device is formed by individual cleaning units 52. These cleaning units 52 are each assigned individually to a heat exchanger unit 32 and are configured on the upper side of the upper housing region 42 by means of an upper washing nozzle assembly 54. This upper washing nozzle assembly 54 is configured with a pipeline 56 for supplying washing liquid (not shown) to a total of eight fixed washing nozzles 58. The individual cleaning unit 52 is further configured on the underside of the lower housing region 38 with a lower washing nozzle assembly 60, in which a washing liquid is guided by means of a pipeline 56 to two rotators 62, which are individually configured with three radially directed rotator arms 64 of different lengths. At the radially outer end regions of each of these rotator arms 64 there is then a washing nozzle 68 which is thus rotatable. Of the three washing nozzles 58, two are directed substantially vertically upwards, while the third washing nozzle 58 is directed obliquely in the direction of rotation of the associated rotator 62 and thus acts as the rotary drive therefor.

[0028] The washing liquid delivered by means of the washing nozzles 58 passes due to gravity into the lower housing region 38, whereby the heat exchanger surfaces are flushed and cleaned. From the lower housing region 38, the washing liquid, which is then loaded with contaminants, is conveyed to a separating device 66, where it can be stored temporarily in a collecting container 68. The collecting container 68 is provided with an agitator 70 for agitating the washing liquid and with a lye-adding device 72 for adding a lye, with a biocide- and/or dispersant-adding device 74 for adding a biocide and/or for adding a dispersant, and optionally with a pH probe 76. Upstream of the collecting container 68 in the flow direction, the separating device 66 is provided with an endless belt filter 78, by means of which the contaminants are to be separated out of the washing liquid. The contaminants are then returned by means of a return device 80 to the material to be dried in one of the dryer sections 16.

[0029] The cleaning units 52 associated with the individual heat exchanger units 32 are to be operated in series one after the other, so that in particular in each case only one of the heat exchanger units 32 is cleaned, while the remaining heat exchanger units 32 are at the same time in operation for heat recovery. To this end, the cleaning device 50 is provided with a switching device 82, by means of which in particular washing liquid supplied through a line 84 by a pump 86 can be allocated to each individual cleaning unit 52 by means of a switching valve 88.

[0030] Finally, it is noted that all the features which have been mentioned in the application documents and in particular in the dependent claims, despite the formal reference which has been made to one or more specific claims, are to be protected independently, individually or in any desired combination.

[0031] While the present invention has been described with reference to exemplary embodiments, it will be readily apparent to those skilled in the art that the invention is not limited to the disclosed or illustrated embodiments but, on the contrary, is intended to cover numerous other modifications, substitutions, variations and broad equivalent arrangements that are included within the spirit and scope of the following claims.

LIST OF REFERENCE NUMERALS

[0032] 10 continuous dryer [0033] 12 transport belt [0034] 14 material feed [0035] 16 dryer section [0036] 18 material delivery [0037] 20 waste air [0038] 22 return air [0039] 24 circulating-air guide [0040] 26 fresh air [0041] 28 air supply [0042] 30 continuous dryer heat exchanger device [0043] 32 heat exchanger unit [0044] 34 housing [0045] 36 waste air channel [0046] 38 lower housing region [0047] 40 ascending housing region [0048] 42 upper housing region [0049] 44 descending housing region [0050] 46 return air channel [0051] 48 fresh air channel [0052] 50 cleaning device [0053] 52 cleaning unit [0054] 54 upper washing nozzle assembly [0055] 56 pipeline [0056] 58 washing nozzle [0057] 60 lower washing nozzle assembly [0058] 62 rotator [0059] 64 rotator arm [0060] 66 separating device [0061] 68 collecting container [0062] 70 agitator [0063] 72 lye-adding device [0064] 74 biocide- and/or dispersant-adding device [0065] 76 pH probe [0066] 78 endless belt filter [0067] 80 return device [0068] 82 switching device [0069] 84 line [0070] 86 pump [0071] 88 switching valve