DE102013020096A1 - Method and device for drying galvanized material - Google Patents

Abstract

The invention relates to the drying of Galvanisiergut 1, which has been treated in a galvanizing plant. Particularly in the case of a galvanized material 1 which has undercuts and holes with a large aspect ratio, drying represents a technical challenge if it is to be of high quality and economical. According to the invention, the galvanizing material 1 to be dried is exposed to different static and dynamic pressures of the drying air 7 in a drying container 2 on the front side and on the rear side. The phase times of the pressures of both sides are controlled so programmatically that first at the beginning of the drying process, the rinsing liquid is completely removed from the holes. Subsequently, the drying takes place from both sides of the Galvanisiergutes 1 with mutual over and under pressures.

Description

The invention relates to the drying of galvanized material which has been treated in a galvanizing plant. Before drying, the galvanized material is thoroughly rinsed with rinse water. This water wets after rinsing all surface areas of the goods. In the dryer, all moisture must be completely removed from the galvanized material. Otherwise, there is a risk of corrosion, which can lead to a committee of the goods. Particularly in the case of cavities and holes, the drying process presents a special challenge if it is to be of high quality and at the same time economical.

The complete drying is usually done with hot air and a correspondingly long drying time. However, this is unsatisfactory because of the great need for energy and time. Therefore, in the document DE 43 36 085 A1 proposed a method by means of movable and oscillating air nozzles. The air jets strike the galvanized material from different directions. For through holes, as they usually occur with printed circuit boards, no special measures are provided. From both sides the galvanizing material is synchronized or not synchronized with air. Therefore, liquid in through holes could be pushed back and forth, but not expelled.

Not least, the technical complexity of such a dryer with moving construction elements is very large. In the publication DE 199 16 784 A1 a dryer is described, which also works with moving nozzles or Düsenblasregister. To support the drying process, dry air is used here. For the requirements that result on Galvanisiergut with through holes, especially with a large aspect ratio, is not discussed.

The object of the invention is to describe an economically operated dryer in wet chemical systems, in particular of electroplating systems for printed circuit boards, which is suitable not only the surfaces of Galvanisiergut, but also through holes and blind holes with a large aspect Ratio, z. 1:20, fast in time and of high quality, d. H. to dry completely.

The problem is solved by the method according to claim 1 and by the device according to claim 6.

The invention provides in Tauchbadanlagen a drying container, which can be closed by means of a lid after the introduction of a goods carrier to which the Galvanisiergut to be dried is attached directly or at least one galvanizing. As a result, different flow velocities or volume flows as well as static and dynamic pressures of the drying air can be realized in the drying container according to the invention. The introduced galvanizing material almost densely divides the drying container into two parts. There is a free space at the front and rear side of the galvanized material which is delimited by the respective container wall or dividing wall. After the introduction of the Galvanisiergut drying air is introduced into the two free spaces. It flows on both sides along the Galvanisiergutes. On one side, z. B. the front of the goods, the air flow leaves the space after flowing past the Galvanisiergut. In the opposite space less drying air is introduced. The exit of this space is closed at this time. Therefore, a largely static overpressure forms in this free space, which can be compensated only by the through holes of the Galvanisiergutes and by some leaks. Due to the fast-flowing drying air at the, in this case, front, on the other hand creates a vacuum after Venturi. Thus, the jammed drying air of the back side flows through the through holes to the front side. It thereby expels the liquid in the through holes. A liquid expelled from the through-holes does not mean that their surfaces are also completely dry. The final drying process must be continued. This post-drying is particularly effective when drying alternately from both sides, i. H. done from the front and from the back of the electroplating. For this purpose, the above-described different flow velocities or volume flows and thus the static and dynamic pressures of the drying air are alternately realized by means of controlled adjusting elements on both sides. The alternating phases of the cycles are program-controlled or fixed depending on the material to be electroplated and its through-holes.

By the respective different pressures on the two sides of the preferably flat Galvanisiergutes such. As printed circuit boards, it is necessary that too large bending of the material is avoided. This is done by a particularly stable attachment of the Galvanisiergutes to the Galvanogestell. As a rule, however, goods with through-holes are thick and therefore very stable, which have a large aspect ratio. z. Eg AR = 1:20. They do not differ even with significant pressure differences on both sides. In contrast, thin printed circuit boards or printed circuit boards usually have through holes with a small aspect ratio. In this case, only small pressure differences on the two sides of the Galvanisiergutes required to expel residual rinse water from the through holes and to dry them further.

The drying process is significantly accelerated in time by the use of dried air as drying air. Surprisingly, it has been found that the dry air makes a significant contribution to energy savings in comparison of commonly used warm circulating air. Although a commercially available dehumidifier, condensation dryer and the like requires significantly higher investment costs compared to hot air, they will pay for themselves in about three years by the energy savings. Because the life of a Galvanoanlage is about 20 years, the invention is also very useful economically and ecologically.

The invention is based on the schematic and only partially to scale 1 further described.

The galvanizing material 1 , here a circuit board with through holes 16 is in a drying container 2 , Between the galvanizing material 1 or the front and the container wall forms a free space 3 out. Correspondingly at the back a free space 4 , The galvanizing material 1 was by means of a known goods carrier 5 in the drying container 2 brought in. Subsequently, the one or two-piece lid 6 closed, so that an approximately air-locked space results, consisting of the open spaces 3 and 4 , The goods carrier 5 as well as the galvanizing material 1 and further construction elements extend in this 1 perpendicular to the plane of the drawing. This dimension can be up to a few meters in practice.

The drying air 7 is through the at least one air inlet duct 12 or corresponding pipes in the open spaces 3 and 4 initiated. To set the different amount of drying air 7 in the two open spaces 3 . 4 are located in the tubes for air induction actuators 8th and 9 , This example is located at the bottom of the drying tank 2 at least one air outlet duct 13 with corresponding pipes for the discharge of the air from the two free spaces 3 . 4 , These tubes contain adjusting elements 10 and 11 ,

Through the air outlet duct 13 the liquid enriched air leaves the drying tank 2 , It is fed to a dehumidifier for dewatering. Its dried air is called drying air 7 again the drying container 2 through the air inlet duct 12 fed. This cycle makes technical sense. The exhaust air of the air outlet duct 13 could also be discarded and to gain the drying air 7 could z. B. room air can be used as input air in the dehumidifier.

Above the open spaces 3 . 4 , as shown in this example, are air inlet pipes, z. B. as nozzle sticks 17 . 18 for the front and back of the goods 1 , For uniform distribution of the drying air 7 preferably extend elongated in the drying container 2 , In the way of drying air 7 to the nozzle sticks 17 . 18 are adjusting elements 8th . 9 , They serve for independent adjustment of the volume flow of the drying air 7 into the open spaces 3 and 4 , At the control elements 8th . 9 such as 10 . 11 can it be z. B. to act automatically controllable analog valves, throttles or flaps. In front of the air outlet duct 13 are the control elements 10 . 11 ,

The reference numerals 14 symbolically show the fixing of the goods 1, to it at both sides different pressures of the drying air 7 to hold in place when it is attached to the product carrier without galvanizing racks.

The reference number 15 shows a scale enlargement of the through holes 16 , This already illustrates the technical requirements for a dryer with galvanizing 1 that has holes with an aspect ratio of z. B. contains 1:20. In practice, there are also through holes with an even larger aspect ratio.

The switching and throttling of the control elements 8th . 9 . 10 . 11 and their mutual phases show the following tables: actuator 8th 9 10 11 on x x throttled x to x change actuator 8th 9 10 11 on x x throttled x to x and so on

It should be noted that preferably at the beginning of the drying process, a longer phase time is set before a first page change of the volume flows takes place. For drying, the cycles can then be set with the same phase times on both sides.

The two-sided surfaces of the material including existing blind holes are dried in any case, even before the through holes are completely dry.

The invention is not limited to the drying of printed circuit boards in electroplating plants. It is also applicable to the drying of other material treated in wet chemical plants.

A humidity sensor in the air outlet duct 13 can be informed, if the drying is finished. In general, however, pre-programmed cycle times are preferred.

LIST OF REFERENCE NUMBERS

1

electroplated

2

drying container

3

Free space front

4

Clearance back

5

goods carriers

6

cover

7

drying air

8th

Actuator front

9

Control element rear side

10

Actuator front

11

Control element rear side

12

Air inlet duct, pipes

13

Luftausleitungskanal

14

fixation

15

scale through hole with AR 1:20

16

Through Hole

17

Nozzle front

18

Nozzle backside

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4336085 A1 [0002]
• DE 19916784 A1 [0003]

Claims (8)

Process for drying galvanized material ( 1 ) located in a drying container ( 2 ) of a dipping facility with free spaces ( 3 . 4 ) at the front and back of the electroplated goods ( 1 ), characterized in that the galvanized material ( 1 ) at the front and on the back of different and mutually changing flow rates and pressures of drying air ( 7 ) in the open spaces ( 3 . 4 ) is suspended. A method according to claim 1, characterized in that at the beginning of the drying as long as an overpressure on one side and a negative pressure on the opposite side of the Galvanisiergutes ( 1 ) in the open spaces ( 3 . 4 ) is maintained until the through holes ( 16 ) are free of liquid. Method according to claim 1, characterized in that after the expulsion of the liquid from the through-holes ( 16 ) the drying of the wetted surfaces of the through-holes ( 16 ) by bilateral on Galvanisiergut ( 1 ) alternating different flow velocities or volume flows and thus different static and dynamic pressures of the drying air ( 7 ) in the open spaces ( 3 . 4 ) is accelerated. Method according to one of the claims 1 to 3, characterized in that as drying air ( 7 ) heated circulating air or dried air is used. Method according to one of the claims 1 to 4, characterized in that the dried air before being introduced into the drying container ( 2 ) and after the drying container ( 2 ) and dried in a dehumidifier or condensation dryer. Apparatus for drying galvanized material ( 1 ) located in a drying container ( 2 ) of a dipping facility with free spaces ( 3 . 4 ) at the front and back of the electroplated goods ( 1 ), for the application of the method according to claim 1, characterized in that by means of controllable adjusting elements ( 8th . 9 . 10 . 11 ) Different flow velocities or volume flows and thus different static and dynamic pressures of the drying air on the two sides of the Galvanisiergutes ( 1 ) in the open spaces ( 3 . 4 ) are adjustable as needed. Device according to claim 6, characterized in that the different flow velocities or volume flows and thus the static and dynamic pressures of the drying air and their two-sided phase times are controllable by means of a control program and / or by means of the data of at least one humidity sensor. Device according to one of the claims 6 to 7, characterized in that the drying air ( 7 ) can be produced by means of dehumidifier or condensation dryer.

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