Visiting Lenzing OptiFil at VW: “Filtration technology by Lenzing Technik decreases maintenance costs and increases productivity,“ emphasized Thomas Kopp (left) when talking to Lenzing Technik Head of Project Andreas Schaale (center) and Heinz–Günther Lieske
(right), Head of Pretreatment and Cataphoretic Painting at the Volkswagen plant in Wolfsburg. (Photos courtesy of Lenzing Technik)
A significantly higher efficiency at a lower cost distinguishes the new degreasing baths, which have been in operation since this summer at Volkswagen in Wolfsburg, Germany, using patented filtration technology by Lenzing Technik. Before paintwork can be applied, car body parts are soaked in a degreasing bath, which can now be cleaned in a specially efficient way with the aid of the Lenzing OptiFil® backwash filter. This has not only considerably extended maintenance intervals, but also enhanced quality of the overall process, as degreasing is a key process in pretreatment.
The degreasing bath is part of a multistage process car body parts have to go through before being painted in order to remove grease and oil residues as well as other impurities from the metal sheets.
“By reducing the maintenance costs, the new degreasing bath by Lenzing Technik enhances productivity,” explained Thomas Kopp, who is in charge of the process at the Volkswagen plant in Wolfsburg. The trouble spots in this process are the heat exchangers, as impurities may adhere to them, which require costly and time-consuming cleaning. As maintenance intervals can be extended here, this increases efficiency and decreases costs. “The new filtration technology aimed at the removal of impurities has fully met our expectations,” Thomas Kopp said about the capabilities of the Lenzing OptiFil backwash filter developed and patented by Lenzing Technik.
wide range of different sectors
This fully automatic backwash filter was originally developed for the filtration of viscose, which is, as the name implies, a viscous solution used in fiber production. Its developers quickly recognized the enormous potential of the Lenzing OptiFil backwash filter for other applications, including low viscosity fluids. Two years ago, they made contact with Volkswagen. “Our filter system is ideally suited for the special requirements of the degreasing bath,” explained Herbert Hummer, managing director of Lenzing Technik. As a matter of fact, when removing the impurities of all different kinds such as extremely light weight dirt particles floating on the surface, heavy iron particles or also long fibers from cleaning cloths used in the alkaline degreasing bath, the Lenzing OptiFil achieves unprecedented levels of quality.
Herbert Hummer, Managing Director of Lenzing Technik, standing next to an automatic backwash
filter by Lenzing.
A positive domino effect
In 2011, the filtration experts of Lenzing Technik presented their idea of how to improve the degreasing process on site in Wolfsburg. As a result of putting Lenzing OptiFil into service, the increased purity of the heat exchangers has lead to lower heating costs on two parallel production lines as well as to extended maintenance intervals and improved quality of the overall process. This positive domino effect is based on the continuous filter system of Lenzing OptiFil, which operates according to the principle of depth, surface or cake filtration. A filter fabric or metal fiber fleece retains dirt particles. As soon as a predefined degree of contamination has been reached, the filter material is cleaned by fully automatic backwashing a small quantity of filtered fluid, while filtration continues.
Joint development work
Lenzing OptiFil is able to purify up to 180 m3 of liquid per hour. As a result, the alkaline degreasing bath is filtered twice within 60 minutes, removing even the smallest particles with a diameter of a few micrometers. A pilot phase of about two years was necessary to find the ideal setup before serial production could begin.
“Working jointly on the development of the backwash filter, we adapted it to the requirements of the process together with the Volkswagen team, finding the ideal filter material and optimizing the overall setup,” said Herbert Hummer.
a true all-rounder
Being highly versatile, the automatic backwash filter by Lenzing Technik is not only in operation at Volkswagen, but can be used by the most different sectors and for a wide range of filtration media, as emphasized by Herbert Hummer. “Lenzing OptiFil is a true all-rounder. It does not only filter all kinds of water, but also chemicals and oils. This is what makes the backwash filter attractive to most sectors: the paper and textile industries, but also to the steel and automotive industries as well as petrochemical applications.”