Context (Patents pending):

For many investors, the pickling bath is remaining the neglected part of a line. However, if a particular care is not brought to the technology of it, the benefit in investment earned via a cheap solution will quickly be caught up by some exploitation costs that will rapidly be very high on a financial point of view.

Indeed, a badly-designed or too short bath will lead to the following problems:

- Acid outlets with, as a consequence, a frequent maintenance of the factory roof and the equipments located in the close surroundings
- The use of scrubbers that are very costly in maintenance
- The very frequent replacement of acid, taking account of the big production of wires
- The use of high working temperatures of acid with, as a consequence, a rapid saturation in acid of the tightness cascades and some acid outlets leading to the above mentioned phenomenon
- The maintenance operations will be carried out in some hazardous conditions such as previous purging of acid, dismounting of the mechanical parts that are in contact with an acid environment and so on

So, the use of a pickling bath has to undergo several constraints for which FIB has particularly optimized its design.

The technology we have opted for is presenting the following Advantages:

An efficient cooling of the wires:

The cooling is made in a specific water tank in order to ensure, on one side, the cooling of the wires and, on the other side, the maximal removal of cracked soap residues on the wires. Thanks to this, the dragging out of the wire drawing soaps in the acid tank can be avoided and so can the accumulation of sludge in the pickling bath be limited.

An optimal use of acid, even for thick wires or for high-speed lines:

1) The acid bath is fed via a special technology with a huge turbulence of acid, which allows working with a quite cold acid (47° in operation) and is limiting the acid losses. Indeed, an acid working at a high temperature is producing, under the cover, a lot of acid vapors that are lost via the condensation of these in the tightness water of the cascades.

2) Between each bath (water-acid and acid-water), FIB Belgium has developed a special system of air knives inside the bath thanks to which the dragging out of some liquid from one bath to another can be avoided. As the air is circulating in a closed circuit, no air charged with acid can escape from the bath. This system is particularly applied on high-speed lines for big diameter wires.

3) In the case of long baths, the acid section is divided in two baths allowing to have at the entrance of the bath an acid that is rapidly loaded with iron, while the second bath is getting polluted in iron more slowly. This system is limiting the volumes of acid that must be sent back to the batch pickling or to the neutralization station and is optimizing the use of acid.

4) The last bath is equipped with a system that is giving the possibility to modulate the immersion length of the wires in acid. So is the second bath not too polluted in iron at the beginning via an eventual over-pickling when some fresh acid is poured into the second bath.

A perfect control of the bath tightness:

The system is made completely tight via a set of water seals and a water cascade at each end of the acid bath. Thanks to this system, the use of scrubbers can be avoided.

An exploitation easiness for the threading up operations:

A threading shuttle located on each side of the bath is allowing the easy threading-up of the wires from one end of the pickling to the other. This system can be operated manually or with the help of an engine.

The operator has a direct access to the wire field at the level of the cooling as well as of the rinsing.

An equipment compactness:

On the acid part, all the instrumentation (pumps and exchangers) has been gathered in a specific tank. This allows the dismounting of the instrumentation without necessarily draining the acid bath.

RM 1.2.1