DE102007024745A1 - Device for drying objects, in particular painted vehicle bodies - Google Patents

Abstract

A device for drying articles (2), in particular painted vehicle bodies, comprises in known manner a drying tunnel (6), the interior of which is filled with an inert gas atmosphere and which has at least one heating device for heating the inert gas atmosphere. A UV irradiation chamber (7) is connected downstream of the drying tunnel (6) and also contains an inert gas atmosphere. The objects can be irradiated in the UV irradiation chamber (7) by means of at least one UV lamp (8, 9), which has a cooling device operating with a cooling medium to dissipate its heat output. The objects to be dried (2) are passed through the drying tunnel (6) and the UV irradiation chamber (7) by means of a conveyor system. For effective energy utilization, the cooling medium of the UV lamp (8, 9) to the drying tunnel (6) traceable and thermally coupled to the prevailing inert gas atmosphere so that the heat generated by the UV lamp (8, 9) partially for heating the inert gas atmosphere in the drying tunnel (6) contributes.

Description

• a) einem Trockentunnel, dessen Innenraum mit einer Inertgasatmosphäre gefüllt ist und mindestens eine Heizeinrichtung zum Erwärmen der Inertgasatmosphäre aufweist;
• b) einer UV-Bestrahlungskammer, die dem Trockentunnel nachgeschaltet ist und ebenfalls eine Inertgasatmosphäre enthält;
• c) mindestens einer UV-Lampe, die in der UV-Bestrahlungskammer angeordnet ist und eine mit einem Kühlmedium arbeitende Kühleinrichtung aufweist;
• d) einem Fördersystem, welches die Gegenstände durch den Trockentunnel und die UV-Bestrahlungskammer hindurchfährt.

The invention relates to a device for drying objects, in particular painted vehicle bodies with

• a) a drying tunnel, the interior of which is filled with an inert gas atmosphere and has at least one heating means for heating the inert gas atmosphere;
• b) a UV irradiation chamber, which is connected downstream of the drying tunnel and also contains an inert gas atmosphere;
• c) at least one UV lamp, which is arranged in the UV irradiation chamber and has a working with a cooling medium cooling device;
• d) a conveyor system which passes the articles through the drying tunnel and the UV irradiation chamber.

Under "Drying device" are understood here all devices, in which a coating material from the condition after application is transferred to the final state, be it through the removal of solvents, melting, crosslinking or the like.

In Recently, coatings increasingly gain importance in an inert gas atmosphere are cured under UV light need to deal with unwanted reactions with ingredients the normal atmosphere, especially with oxygen, too prevent. These novel paints are characterized by a very high surface hardness and short curing times out. The latter advantage is in paint shops, the be operated in a continuous cycle, immediately in smaller plant lengths which, of course, leads to significantly lower investment costs leads.

An example of such a drying device is in DE 10 2004 025 525 B3 described.

at all industrial installations, but especially dryers for large items, like them for example Represent vehicle bodies, there is always the need for an efficient use of energy. That's why it's up to you the present invention, a device of the aforementioned Designing the way that largely avoids energy losses become.

• e) das Kühlmedium der UV-Lampe zum Trockentunnel zurück führbar und dort wärmemäßig an die darin herrschende Inertgasatmosphäre so ankoppelbar ist, dass die von der UV-Lampe erzeugte Wärme teilweise zur Erwärmung des Trockentunnels beiträgt.

This object is achieved in that

• e) the cooling medium of the UV lamp can be guided back to the drying tunnel and there heat-coupled to the prevailing inert gas atmosphere in such a manner that the heat generated by the UV lamp partially contributes to heating the drying tunnel.

The Invention is based on the knowledge that in the or The heat generated by the UV lamps as "waste" is usefully used can be and in particular for heating the inert gas atmosphere, the is in the drying tunnel. That way, the performance can be the heaters used there are reduced. These Knowledge is not as banal as it possibly is seems to be listening at the first moment. Indeed it requires a very intimate knowledge of the thermotechnical processes and processes in a generic drying device. Whether the recovery of heat, in a given Plant part is generated, and their reintroduction into the plant worthwhile in another place, requires more accurate Calculations and investigations.

The Cooling medium is preferably via a heat exchanger can be coupled to the inert gas atmosphere. In this way remains the cooling medium, which is preferably at Water or air, separated from the inert gas atmosphere and the inert gas atmosphere clean.

Preferably is the cooling medium in the heating heat can be coupled to the inert gas atmosphere of the drying tunnel. As is known, the painted and to be dried objects in First move the drying tunnel into an area with rising Temperature led to there by a first slow warming to initiate the dry processes, often with the evolution of gases and / or vapors are connected. Because in this area, as mentioned, the Temperature of the inert gas atmosphere still relatively is low, the one coming from the UV lamp (s), heated and not too high temperature cooling medium There especially good to support the heaters.

Prefers condensate traps are used to produce condensable impurities to remove from the inert gas atmosphere. If the inert gas obtained by evaporation of a liquid can the condensate traps energetically with the evaporator for Energy savings are coupled.

In certain applications, it has to be favorable proven when a plurality of UV lamps on at least one wall the UV irradiation chamber is arranged such that it corresponds to the in surface of the UV radiation chamber can irradiate. Preferably, both the side walls as well as the ceiling of the UV irradiation chamber surface with UV lamps Mistake.

In In other cases it is convenient to have a plurality of To arrange UV lamps in a portal so that the to be irradiated Move the item through the portal. The arrangement of UV lamps in such portals is rather linear. Often In portals, more powerful UV lamps are used as in flat arrangement.

Of course It is possible in one and the same drying device to use both types of arrangement of UV lamps in a row.

to Irradiation of the interiors of the objects can one or more UV lamps also attached to the arm of a robot be introduced with them into these interiors can be.

One Embodiment of the invention will be described below the drawing explained in more detail; show it

1 in vertical section an overall view of a drying device for vehicle bodies;

2 an enlargement of the left end of the 1 ;

3 a top view of the in 2 illustrated end portion of the drying device;

4 an enlargement of the right end of the 1 ;

5 a top view of the in 4 illustrated end portion of the drying device.

First, it will open 1 Reference is made in which a total with the reference numeral 1 characterized drying device for vehicle bodies in vertical section and in the overall overview is shown. This drying device 1 is integrated into a painting line. Its preceded by the actual paint booth to think in which the vehicle bodies, in the figures by the reference numeral 2 are coated with a coating in an inert gas atmosphere and UV curing varnish. Downstream of in 1 The drying device shown is a cooling device, in which the dried, so provided with a polymerized paint layer vehicle bodies 2 be cooled to a suitable temperature for further processing. Both the upstream paint booth and the downstream cooling device are of conventional construction and are therefore not described in detail.

The vehicle bodies 2 be through the drying device 1 by means of a conveyor system, not shown, cyclically or continuously moved through and in the direction of the arrow 3 from 1 ie in 1 left to right. The vehicle bodies 2 arrive first in a so-called A-lock 4 in which they by means of a lifting device 5 be raised to a higher level. The meaning of the A lock 4 which is known to those skilled in the art, in the present case not only in the saving of heat energy but also in the vehicle bodies 2 from the "normal atmosphere" in which they are at the lower level, in an inert gas atmosphere, which in the parts of the drying device described below 1 prevails.

From the A lock 4 kick the vehicle bodies 2 , the direction of the arrow 3 following, in different drying chambers 6 the drying device 1 which together form a drying tunnel. All these drying chambers 6 are heated in a known manner by means of a circulating air heater, not shown, to a certain temperature. In the first drying chambers 6 this temperature rises initially; this area is called "heating zone". After passing through the heating zone get the vehicle bodies 2 in a series of drying chambers 6 in which essentially a constant temperature is maintained. The number of drying chambers belonging to the heating zone 6 and the number of drying zones belonging to the "holding zone" 6 is chosen according to the respective needs and is in 1 only as an example.

After passing through all drying chambers 6 become the vehicle bodies 2 transported by means of the conveyor system in a UV irradiation chamber, the overall reference numeral 7 wearing. The UV irradiation chamber 7 in turn is in three sections 7a . 7b . 7c divided. In the first part 7a along the chamber walls is a variety of UV lamps 8th arranged, which, so to speak, a "total lighting" of the vehicle bodies 2 from the sides and from above. After passing through the UV zone free intermediate zone 7b get the vehicle body into the section 7c in which UV lamps 9 are mounted on robots with which after opening the doors and / or hoods by door / Dome openers the interior is irradiated. Behind the outlet of the UV irradiation chamber 7 there is an intermediate chamber 10 , followed by a so-called piston lock 11 , whose meaning will be discussed below, as well as another A lock 12 in which the vehicle bodies 2 by means of a hoist 13 be lowered back to its original level. Am in the direction of movement (arrow 3 ) rear end of the dry contraption 1 there are outlet chambers 14 which may serve for intermediate cooling and / or quality control.

At least the two A-locks 4 . 12 as well as the piston lock 11 and the UV irradiation chamber 7 are provided with inlet and outlet ports, for example in the form of lifting gates, which only for the passage of a vehicle body 2 be opened and so an atmospheric separation to adjacent chambers of the drying device 1 guarantee. Details in this connection are not of interest here.

The UV lamps 8th . 9 that are in the UV irradiation chamber 7 are located, have a considerable connected load and require cooling. For this purpose, cooling circuits are provided, through which a cooling medium circulates. The latter may be a gas or a liquid. The following is based on the use of cooling water. That of the UV lamps 8th . 9 heated cooling water is over the line 15 against the direction of movement (arrow 3 ) of the vehicle bodies 2 the first two drying chambers 6 in the heating zone of the drying device 1 fed where they give off in a heat exchanger, not shown, a part of its heat content to the atmosphere circulated there. This way, in the first two drying chambers 6 Saved heating energy. The cooled cooling water is over the line 16 back to the UV irradiation chamber 7 and there to the UV lamps 8th . 9 guided.

Below the drying chambers 6 There are condensate traps in two places 17 . 18 which may optionally be cooled and via which condensable impurities from the atmosphere of the drying chambers 6 can be dissipated. You can be energetically coupled with the evaporator described in more detail below, so that energy is saved here.

As already mentioned, the interior of the drying device 1 filled with inert gas, for example with nitrogen, CO ₂ , a noble gas or a low-oxygen flue gas. The inert gas atmosphere begins in the upper part of the A-lock 4 and ends in the piston lock 11 ,

The piston lock 11 is to avoid inert gas losses with a piston 19 provided whose base surface (seen from above) is adapted to the horizontal cross section of the piston lock chamber. If there is no vehicle body in the piston lock 11 , the piston can 19 pressed down. In this case, the inert gas atmosphere located there is via a line 20 in that drying chamber 6 introduced with which the holding zone of the drying device 1 starts. About another line 21 will be in this drying chamber 6 Inert gas atmosphere back to the piston lock 11 guided. This replacement of the inert gas is used in particular for flushing the vehicle bodies 2 placed in the holding area of the drying device 1 enter to completely remove adhering normal atmosphere.

Below the higher level section of the dryer 1 , near the UV irradiation chamber 7 , is a storage tank 22 arranged, in which liquid inert gas, for example, liquid nitrogen, is located. With an evaporator device, not shown, the inert gas can be evaporated as needed. The storage tank 22 is over a line 23 with the interior of a cylinder 24 connected, in which a piston 25 can be moved by means of a suitable drive device. Another line 26 connects the interior of the cylinder 24 with the interior of the UV irradiation chamber 7 , The wires 23 and 26 contain valves, not shown, as required for the operation described below.

The administration 23 can also be via heat exchanger of condensate traps 17 . 18 be led, so that on the one hand the condensate traps 17 . 18 cooled and on the other hand, the UV irradiation chamber 7 supplied inert gas is heated.

The drying device described above 1 works as follows:
The freshly painted and only slightly evaporated vehicle bodies 2 be with the help of the conveyor system in the A-lock 4 retracted and there with the help of the hoist 5 brought to the higher level. The vehicle bodies 2 already pass into an inert gas atmosphere, in countercurrent, from the UV irradiation chamber 7 Coming, all chambers of the drying device 1 has gone through. Due to carryover of normal atmosphere, the inert gas atmosphere is in the area of the inlet A-lock 4 most polluted. There is the dirty inert gas over another line 27 withdrawn and either discarded or reused after cleaning.

The vehicle bodies 2 now move to the higher level in 1 to the right (direction of the arrow 3 ) and get into the first drying chambers 6 of the drying tunnel. There they are heated at still behässismäßig low temperatures of the circulating atmosphere, the heat content at least partially from the UV lamps 8th . 9 in the UV irradiation chamber 7 had received. On the way through the heating zone, the temperature is slowly increased. The individual drying chambers 6 can do it But they do not have to be separated by gates. In any case, it is advantageous if the atmospheres in the individual drying chambers 6 are reasonably separated from each other, so that a defined temperature profile can be maintained in the heating zone. Condensable substances in the heating zone of the vehicle bodies 6 evaporate, be with the condensate trap 17 condensed out and removed.

The vehicle bodies 2 then enter the first drying chamber 6 the holding zone. There they are, as already explained above, purged with inert gas, which from the piston lock 11 comes where the inert gas atmosphere is still relatively clean. On further passage through the drying chambers 6 If necessary, remaining solvents are expelled from the holding zone and the coating material prepared for crosslinking. Condensable material accumulating in this area is transferred via the condensate trap 18 removed, so that the inert gas is not unnecessarily polluted.

Now the vehicle bodies kick 2 in the UV-irradiation chamber 7 one. There, the inert gas atmosphere must be the cleanest to the crosslinking process, which under the influence of the UV lamps 8th . 9 emitted UV light takes place, not to be affected. Therefore, the UV irradiation chamber 7 at regular intervals, in extreme cases at each cycle of the drying device 1 to be refilled with inert gas. In order to achieve high flow rates, the filling with inert gas must be done quickly. Since the evaporation of liquid inert gas in the reservoir 22 can not be performed as rapidly as desired by evaporators of reasonable performance, is the piston-cylinder unit 24 . 25 intended. She works as follows:
During the time in which the coating on one (or more) vehicle bodies 2 in the UV irradiation chamber 7 cured under irradiation with UV light, generates the evaporator device in the storage tank 22 continuously gaseous inert gas. This accumulates in the cylinder 24 , where the piston 25 is reduced accordingly. At the end of the irradiation time has become in the cylinder 24 accumulated as much gaseous inert gas as for the next irradiation process in the UV irradiation chamber 7 is needed. So if the vehicle bodies 2 during the collection of the evaporated inert gas in the cylinder 24 have been irradiated from the UV irradiation chamber 7 can go out by pushing the piston 25 in the cylinder 24 the accumulated inert gas over the line 26 into the UV irradiation chamber 7 be pressed. This is possible in a comparatively short time, although the evaporator means the liquid inert gas in the storage tank 22 can evaporate only relatively slowly.

The vehicle bodies 2 So are in highly pure inert gas atmosphere within the UV irradiation chamber 7 first of the UV lamps 8th irradiated, which area of the two sides and from above the vehicle body 2 illuminate. In this case, the polymerization of the coating material takes place on the outer surfaces of the vehicle bodies 2 , After passing through the intermediate area 7b in the UV irradiation chamber 7 become the interiors of the vehicle bodies 2 through the robotic UV lamps 9 irradiated. About the intermediate chamber 10 become the vehicle bodies 2 first in the piston lock 11 and then from this to the top of the A lock 12 brought in. By lowering the lifting device 13 arrive the vehicle bodies 2 back to the low level and leave the dryer 1 over the outlet chambers 14 towards the cooler.

Part of the waste heat of the UV lamps 8th . 9 can also be used to preheat the from the storage tank 22 over the cylinder 24 into the UV irradiation chamber 7 introduced inert gas or to operate the condensate traps 17 . 18 be used.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 102004025525 B3 [0004]

Claims (9)

Device for drying articles, in particular painted vehicle bodies, having a) a drying tunnel, the interior of which is filled with an inert gas atmosphere and which has at least one heating device for heating the inert gas atmosphere; b) a UV irradiation chamber, which is connected downstream of the drying tunnel and also contains an inert gas atmosphere; c) at least one UV lamp, which is arranged in the UV irradiation chamber and has a working with a cooling medium cooling device; d) a conveyor system which passes the articles through the drying tunnel and the UV irradiation chamber; characterized in that e) the cooling medium of the UV lamp ( 8th . 9 ) to the drying tunnel ( 6 ) and where it can be thermally coupled to the inert gas atmosphere prevailing there in such a way that the light emitted by the UV lamp ( 8th . 9 ) generated heat partially for heating the inert gas atmosphere in the drying tunnel ( 6 ) contributes. Apparatus according to claim 1, characterized in that the cooling medium via a heat exchanger is coupled to the inert gas atmosphere. Device according to Claim 1 or 2, characterized that the cooling medium is a liquid, in particular Water, is. Device according to Claim 1 or 2, characterized the cooling medium is a gas, in particular air. Device according to one of the preceding claims, characterized in that the cooling medium in the heating area thermally to the inert gas atmosphere in the drying tunnel ( 6 ) can be coupled. Device according to one of the preceding claims, characterized in that a plurality of UV lamps ( 8th ) on at least one wall of the UV irradiation chamber ( 7 ) is arranged such that it in the UV irradiation chamber ( 7 ) can radiate flat surface. Device according to one of the preceding claims, characterized in that a plurality of UV lamps in a portal is arranged such that the object to be irradiated ( 2 ) can move through the portal. Device according to one of the preceding claims, characterized in that at least one UV lamp ( 9 ) is arranged on the arm of a robot. Device according to one of claims 3 or 5 to 8, characterized in that in the Inertgasatmos phere at least one condensate trap ( 17 . 18 ) which is in heat exchange with an evaporator unit for the liquid cooling medium.