Multilayered blended mesh in beer filtration: Practical tests confirm efficiency

With its multilayered blended mesh made of mono- and multifilaments, YMAX®, the internationally renowned technical weaving mill for wire mesh made of metal, plastics or fibers, GKD - Gebr. Kufferath AG, Dueren, has developed a novel filter media which meets the typical requirements of the branch to a previously unattained degree. The mesh structure of monofilament stainless steel wires and metallic fibers combines surface and depth filtration in a single media. The core properties of this innovative media - high porosity, mechanical stability, flexibility and absolutely consistent distribution of pores - qualify it in particular for applications in the field of solid/liquid filtration in the range of 20 to 30 µm with high mechanical stress, i.e. for applications in which wire mesh was not previously accepted. Comprehensive series of tests in cooperation with various partners have proven the great efficiency of YMAX®. This has now been impressively confirmed through the latest practical tests in one of the major brewery groups in Asia.

Today, YMAX® is an established product in a range of applications. Two-layered constructions have proven themselves in particular in filter elements for precoat filtration. Compared to the average porosity of sintered material structures of around 20 percent, YMAX®, thanks to its special mesh structure, achieves a porosity of 60 percent, which means considerably higher efficiency for the same size of filter element. This is supported by the great accuracy of cut-point in particle retention. The multilayered structure also guarantees excellent drainage properties. High throughput rates combined with low differential pressure and long service life due to the thermal, chemical and mechanical durability of the working material 1.4404 (316L) Stainless Steel are further aspects of the efficiency of this filter media.

Efficiency already proven in tests

The excellent results of previous trials with YMAX® were the basis for the decision to conduct the practical tests which have been running in Asia since May. Here, two-layered constructions have been used in already existing filter elements for precoat filtration. The results of trials with the two-layered, 0.8 mm thick YMAX® consistently verify the good separation performance as well as a significant extension of filter service lives and a high potential reduction of filter aids. Previously typical times for precoating in beer filtration have been more than halved. Even after just a few minutes, from the first clear run of product onwards, the filtration process is stable. In a comparison with conventional filter media, turbidity on an EBC scale was compared in a graph of 25°and 90° scatter angles. The course of the curve clearly indicates the significant shortening of precoat filtration times and the absolute stability of the filtration process when the new filter media is used. Fluctuations in turbidity runs like those which occur with conventional filter media do not take place with YMAX®. The quality of cut-point also sets new standards. With YMAX®, the limit value of 10,000 particles/100 ml was consistently undercut with results ranging between 4,000 and 6,300 particles/100 ml. This is achieved through the multifilament structure of the filter media, which even retains those particles which change their form and consistency during the filtration process. During backwashing, the special YMAX® pore structure guarantees very good pressure distribution while at the same time ensuring that there is practically no blocking of edgezones as for example when perforated sheets are used.

Standing ovations for YMAX® in practical tests

The new filter media had already caught the attention of the major brewery group in Asia two years ago. That initial contact was deepened at the Interbrau fair in Munich in Autumn 2002 and the practical implementation of the mesh was agreed. After extensive tests of its own, the Asian brewers used YMAX® 2 on a horizontal filter with a filtration surface area of 52 sqm. Although the blended mesh is a little thicker than conventional filter media, there is no problem in installing it into all existing filter elements. The practical trial run not only confirmed previous test results but even surpassed all expectations. Since the start on 5th May, consumption of filter aids has been reduced by more than 60 percent. The process is stable after only 15 minutes. The filtration results show previously unattained low levels of particulate residues: EBC values of 0.17 to 0.25 at the peak clearly undercut the typical values of 0.35 - 0.45. The filtration runs were performed up to a differential pressure of 6 bar. The filtration performance of the new filter media also sets new standards in terms of efficiency: 2,700 hl were achieved in the first filtration run. "In the first filtration runs, there were standing ovations for the new media", says Udo Neubauer, a GKD support technician. By the beginning of July, filtration had been running at this high level with consistent stability for over eight weeks.

Jürgen Bergschneider, Manager of the Business Unit SOLID WEAVE at GKD, was on location to follow the practical tests in person. He sees the reasons for the excellent performance of the multilayered filter media not only in its innovative mesh structure. "Installations like this also prove how important it is to individually adjust the filter aids used." GKD offers the service of checking that the mixture of filter aids used is optimal and, if necessary, of making appropriate recommendations. With equipment which can implement such individual recommendations, there is a significant additional support for the functional properties of the blended mesh made of stainless steel wires and stainless steel fibers. A sign of how satisfied the Asian brewers are: if the positive practical results continue to prove themselves, YMAX® will also be implemented in other locations when the filters there are next due to be changed.