Method and device for extracting, heating, and recirculating waste air from a dryer system

Abstract

A method for efficient utilization of hot air flows in a dryer system for goods to be dried is provided, in particular for a vehicle painting plant. Waste air from the dryer is heated in a thermal post-combustion plant and, as clean gas is conducted through circulating air recuperators, the circulating air extracted from the dryer is heated up and returned into the dryer. A device for efficient utilization of the hot air flows in a dryer system for goods to be dried is also provided, in particular for a vehicle painting system. The device includes a dryer, the waste air of which is heated in a thermal post-combustion plant. Clean gas is fed to circulating air recuperators and at least one fresh air recuperator. At least one additional heat source for the clean gas is also provided.

Claims

1. A device for the efficient utilization of hot air flows in a dryer system for goods to be dried, comprising: a dryer, the waste air of which is heated in a thermal post-combustion plant and can be returned as clean gas to circulating air recuperators and at least one fresh air recuperator; at least one additional heat source for the clean gas; and an air recirculating system comprising: a clean gas line; and at least one return line, which is guided parallel to the clean gas line; wherein a last circulating air recuperator is disposed at a first end of the clean gas line and the at least one additional heat source is disposed at a second end of the clean gas line the second end being opposite to the first end, and wherein the return gas line is connected to the clean gas line directly before the at least one additional heat source and after the connection of the last circulating air recuperator.

2. The device according to claim 1, wherein the additional heat source is an additional burner.

3. The device according to claim 1, wherein the additional heat source is assigned to the clean gas line upstream of the first circulating air recuperator.

4. The device according to claim 1, wherein at least one fan is arranged in the return line.

5. The device according to claim 1, wherein at least one closure element for the media conducted through the return line is arranged in the return line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The sole drawing schematically illustrates an exemplary embodiment of the method according to the invention and of the device according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(2) The dryer 1 has an entry lock 2, a heating-up zone 3, a holding zone 4 and an exit lock 5. The arrow 6 symbolises the introduction of the goods to be dried, for example bodies, which are situated on SKIDs. The arrow 7 symbolises the input of the solvents which are introduced in the dryer with the paint coatings of the goods to be dried. The arrow 8 symbolises the dried goods leaving the dryer and SKIDs. The thermal post-combustion plant TNV is marked with 9. 10 to 13 are circulating air recuperators. 13a is a waste air recuperator and 15 is a fresh air recuperator. 21 marks a waste air stack. The arrows 22 designate the feeding of fresh air from the environment. The waste air lines are marked with 18 and the circulating air lines are marked with 17.

(3) The waste air (raw gas) extracted from the dryer 1 via the waste air lines 18 is fed to the TNV 9 via a fan unit 19 and the waste air recuperator 13a, where it is subjected to the oxidation process. The waste air purified through the conversion leaves the TNV 9 as clean gas in the clean gas line 20. The clean gas is initially conducted through the waste air recuperator 13a, then through the circulating air recuperators 10 to 13 and finally flows through the fresh air recuperator 15, following which it exits into the atmosphere via the waste air stack 21.

(4) Flaps 26 are inserted in the clean gas line 20. These correspond to flaps in diversions 27 of the clean gas line 20. In the diversion 27, a circulating air recuperator 10 to 13 each is inserted, the last circulating air recuperator 13 being assigned a bypass line 16 with a corresponding flap 26.

(5) The flaps 26 establish a controlled through-flow of the clean gas and circulating air through the circulating air recuperators 10 to 13. Circulating air and the clean gas are no longer controlled, rather the temperature of the clean gas and circulating air is controlled. The addition burner 14, which acts on the clean gas line 20 via a line section 22 serves for this purpose. The additional burner 14 is operated via a control line, which is linked to a temperature sensor 24 in the last circulating air recuperator circuit.

(6) The clean gas line 20 is connected to a return line 25 before entering the last circulating air recuperator 13. The return line 25 leads back into the region of the original burner 14, where it is linked to the line section 22. A fan 27 and a closure flap 28 are inserted in the return line 25.

(7) Further fans are additionally inserted in the circulating air lines 17 and the fresh air line.