Deep in the southwestern corner of Germany, in a region known affectionately by locals as the ?Ländle?, ?the little country?, stands Weitmann & Konrad (Weko), the inventor of a non-contact rotor system for precise, metered application of liquids and chemicals to fabrics. In an interview, Weko Product Manager Thomas Laißle explains why global players in the paper, textile, tissue and foil industries have come to rely on the liquid application system from the Baden-Württemberg based, owner-managed company with a workforce of 140, and why it helps them to save enormous quantities of water, energy and chemicals.
Sustainability is a broad field. As a member of VDMA, what specific approach does Weko associate with the subject?
These days, the highest priority for any responsibly trading business, which we consider ourselves to be, is to use resources as economically as possible and implement sustainable manufacturing practices. Accordingly, with our systems we place considerable emphasis on the subject of ?economising?. It is true that the subject of sustainability is most often associated with the power generation and storage segment.
Of course, that is very important, but it does not represent the whole picture: sometimes one tends to forget that it is also imperative to conserve water, energy, and chemicals in industrial manufacturing precisely because this approach, together with upgrading to appropriate technology and continuous optimisation of existing production processes, also helps significantly to reduce the environmental burden.
You are alluding to the non-contact rotor system for coating surfaces, which can be integrated in existing systems. How does that work?
Surface coating is part of the standard procedure in the paper, textile, printing or foil industries, for example. It is a way to endow the base material, produced in webs, with certain functional properties that are not intrinsic to the base material alone, such as flame retardant properties, softness, antimicrobial/antibacterial, hydrophilic/hydrophobic or oleophilic/oleophilic additives. With our rotor, which work like a rapidly rotating disc, the corresponding liquids can be applied without contact and continuously according to a precise quantity specification. Unlike the conventional technology, the contactless application means that the surface to be coated is not subjected to any mechanical load. In addition, the distribution of the liquid is improved considerably, because it is applied as a homogeneous stream of fine micro droplets.
Please explain the advantages of this economising approach with an example?
? woven fabrics. For these products padding is the traditional method for the finishing. In padding, the textile to be treated is transported through a liquid or auxiliary bath as a web. As a result, it is more than just the essential quantity of liquid applied, but it also penetrates practically the entire textile, so it has to be squeezed out afterwards using nip rollers and then dried to remove the excess liquid. As an illustration: Before coating, the absolute moisture content of a conventional textile is in the order of 8-10 percent; this means that 1 kg of material contains 80-100 grams of water. After padding, the moisture content in the material is about 60-70 percent. Drying processes that consume a great deal of energy have to be applied to lower the moisture content to a normal level again.
On the other hand, with the Weko liquid application system the woven goods only have an absolute moisture content of about 20-30 percent after coating, and much less energy is needed to reduce this to the required 8-10 percent ? this corresponds to about 40 percent less drying power than is needed in the paddding process.
With our approach, only the quan