Not less than three! gigantic melt filters now have left the plant of the Kreyenborg GmbH in Münster. Each of these systems of the new type series Poly presents the biggest screen changer which has ever been constructed. These giants have been designed for the use in world-scale polymerisation lines instead of conventional candle filters. With a maximum throughput of up to 45.000 kg/h, depending on material, viscosity and filter fineness, these machines move into completely new dimensions.

The latest screen changers of the type Poly are to be recognized already by few characteristics. Contrary to most of the conventional screen changers, the housings are designed horizontally, so that the individual pistons are arranged side by side and not one upon the other. Every piston disposes of two opposed screen cavities. Screen changers with two or four pistons are available, whereas the version with four pistons shows a considerably better process pressure constancy. As usual with the screen changers, a breaker plate and the stainless steel wire-cloth screen pack are arranged within the oval screen cavities. Additionally, the machines of the Poly type series are equipped with special screen retainers. These screen retainers arrange for an always tight fit of the screen packs and fluidic optimisation. Furthermore, they reduce the melt volume during screen change as well as the already very low residence time of the Polymer in the filter.

Kreyenborg, being world market- and technology leader for screen changers, has put its complete experience into the development of the new screen changers for polymerisation. It has been managed to design a machine which offers the user essential economic advantages compared to conventional filter systems in polymerisation lines. Especially the cleaning of the filters is less complex and more favourable in price. Owing to the use of inexpensive flat screens all habitual advantages of a screen changer – like the always continuous production and the easy handling – are achieved. Thus the machines of the type Poly, supplied by Kreyenborg, are the first adequate screen changers for world-scale polymerisation lines.

The biggest version is the Poly 6000×4, which has a total filtration area of 24,000 cm², resulting from 6,000 cm² in each of the four pistons. Depending on material and viscosity the throughput amounts to up to 45,000 kg/h. The three machines of this size, which have been delivered now, will be applied with PET production in the MTR®-process of Uhde Inventa-Fischer. Two filters have been delivered to Indorama in Alabama USA , the third screen changer has been shipped to Alco-Naphta LLC inKaliningrad Russia. When the first screen changer will be brought on line in the course of next year, the new Kreyenborg system may demonstrate its efficiency.