Mechanical wiping systems
Wire KÖRNER offers mechanical systems mainly designed for commercial galvanisation at 30 to 130 g/m², with long-lasting wiping pads for vertical or oblique removal.
Their distinguishing feature is how easy they are to maintain, because the pads can be changed within two minutes.
Nitrogen wiping systems
Nitrogen wiping systems are used for class A, B and C coatings with high DxV. They are ideal for:
- Wire diameters between 0.8 and 9.0 mm,
- Zinc coatings between 85 and 600 g/m².
The manual adjustment control allows the wiping nozzles to be precisely set and calibrated along multiple axes. This ensures that the wire runs concentrically through the nozzle, and that an even thickness of zinc coating is laid down over its entire circumference.
The individual wire-feed makes it possible simultaneously to coat wires of different diameters, and hence differing speeds, in the same piece of equipment.
In comparison with traditional systems, equipment speeds up to 300 percent higher can be handled. This means a considerable increase in productivity for the whole piece of equipment.
The nozzles are made from hardened stainless steel and are therefore very low-maintenance.
Quenching the wire with water ensures that the zinc coating is fixed before the wire reaches the deflection roller.
Systems with automatic control
The AZCS (Automatic Zinc Coating Thickness) system that is used in conjunction with the nitrogen wiping further improves product quality: it precisely regulates the coating of zinc, and achieves, in this way, not only an even and reproducible thickness of coating, but also high surface-quality.
Automatic measurement of the thickness of the zinc-coating on every single wire determines the input size for the automatic control of the nitrogen throughput to the individual nozzles. The controls can be set individually for each diameter of wire. Control accuracy is five percent. The results are impressive: the system reduces variations in coating thickness to less than 5 percent, which corresponds to approximately 10 to 15 g/m².
The automatic system also reduces zinc consumption, because the thickness of the zinc coating is always maintained close to the target value, and excess zinc drips down immediately into the zinc bath. Over and above this, the nitrogen which is used for wiping reduces the formation of zinc ash, which brings with it yet more saving in zinc.
Process monitoring with AZCS ensures that no rejects are produced. If the screen is showing “green”, the galvanizing process is running perfectly.
Especially when combined with precise manual setting of the wiping nozzles, the automatic nitrogen-throughput control achieves optimum results –in both the concentricity and the evenness of the zinc coating.
On top of this, there is no need to go to the expense of making manual spot checks during production.
… and the costs
Zinc wiping with AZCS is extremely economical; under normal conditions it saves four- or even five-figure euro sums annually.
An example from the real world: with an annual production duration of 7,200 hours and a total of 24 wires, the automatic nitrogen wiping-system saves up to 500 tonnes of zinc a year.