The new filter combination of the BKG® screen changer from Nordson is able to withstand the squeezing pressure, providing maximum filtration and optimum melt flow; it lasts longer than the low-end filter combination on the market. more reliable.
A key factor in enhancing the performance of the new filter combination is the powerful multi-layer structure that prevents the pressure differential (up to 200 bar) encountered during filtration from causing failure. One such failure is the 'filter sag', here In this case, mechanical stress pushes the mesh into the hole in the circuit breaker plate of the filter in the support cavity. This distort the filter and damage the surrounding seal, causing contaminants to bypass the filter and become part of the final product.
Screen changer with filter combination
Nordson precisely adjusts the size of the filter combination to the cavity size, eliminating the common problem of contaminants passing through the filter at the edge. In addition, during the production process, all filter assemblies are ultrasonically pre-cleaned to Eliminate the pollution caused by the oil and grease used in the weaving process.
'The new Nordson filter combination design maintains structural integrity while effectively filtering contaminants and ensuring optimum melt permeability,' said Christian Schroeder, Global Product Manager for Melt Conveying Systems. 'So our The filter combination produces higher output combinations between screens than other low-cost filters, which increases the productivity of the extrusion line and increases profitability.'
Filter combination four-layer structure
According to customer requirements, Nordson offers different combinations of mesh layers for filter combinations. For example, one common structure consists of four layers, two layers are rough square braids, used as external components, and one layer is more elaborate. Internal square braid. They provide support and drainage and withstand high tensile forces. The fourth layer is an optimized Dutch woven wire mesh for fine filtration components. The small geometrical aperture of the Dutch braid ensures high permeability. Relative to the melt The direction of flow, filtered in the transverse direction, promotes the effective separation of dirt particles from the melt.
'The key factor for effective filtration is permeability,' says application engineer Stefan Woestmann. 'The Nordson filter combination provides the best ratio of solid material and free volume, so the polymer melt can be used to pass through as many flow paths as possible. Filter media. In the production process using low-end filters, the polymer melt does not get this flow optimization, resulting in build-up and a significant increase in pressure. This can lead to premature and expensive filter replacement and endanger The quality of the final product. If the polymer flows unevenly, the final product is not uniform.