Filters with a plastic flushing channel
Plastic instead of Stainless Steel
Mahle Filtersysteme GmbH in Öhringen, Germany, has now fitted one of its filters with a plastic flushing channel. Previously, the channel was made of stainless steel and consisted of more than 20 individual parts. Maker of these complex plastic parts is Protoform Konrad Hofmann GmbH in Fürth, Germany. For many years, the company has specialized in the patented SPM (space puzzle molding) process. Regarding their suitability for injection molding, the components are either developed by the customer and then optimized by the Protoform design department or are developed by Protoform to customer specifications using CAD. Based on the data, the injection molds are then designed, and after conversion into CNC machining programs, the in-house tooling department makes aluminum molds. SPM permits the fast and cost-effective production of plastic parts with manual de-molding and in batches up to 3,000.
One of the previous more than 20 individual parts was a wear-prone scraper blade made of PTFE or PU. Under normal operating conditions, this scraper blade had to be replaced every two to three years. During development work, the Mahle application engineers asked for an inlay to be integrated, which would enable them to respond to changing conditions more quickly and cost-effectively. For Protoform, this meant an additional task had to be solved: A pressure-tight connection was required between the two parts of the flushing channel. This task was solved by injection assembly molding without additional processing. The result of this optimized injection molding – which included equalization of material accumulations, dimensioning of wall thicknesses, design of the ribs, and the application of a threaded connection – was a component that complied with all the functional requirements.
With their automated cleaning and disposal sequences, automatic metal edge filters permit rational non-stop operation of production plants, and are suitable for a wide range of media. Mahle’s patented segment cleaning by means of external pressure surges now works even more efficiently, and helps reduce operating costs for the filter user. The flushing channel of PPS-GF40 (grade: Fortron; manufacturer: Ticona GmbH) is certified for continuous operating temperatures up to 180°C, resistant to chemicals, pressure tested up to 8 bar, maintenance-free, and considerably more cost-effective than the previous version. Meanwhile, Mahle is in the process of applying the plastic flushing channel to all other automatic filter types.
protoform K. Hofmann GmbH
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