C. Straube, G. Yang, D. Voll, J. Meyer, P. Théato, A. Dittler

Separation and Purification Technology, 2022, 290, 120802, https://doi.org/10.1016/j.seppur.2022.120802

Industrially applied coalescence filters, e.g. oil mist filters, usually consist of several filter layers in combination with a downstream support grid. While in the past the focus of research on coalescence filters has been e.g. on the filter media itself, information on the influence of support structures on pressure drop and entrainment is scarce. Recent studies on the influence of support structures on differential pressure and entrainment showed, that stainless-steel perforated sheets are particularly well suited for this purpose. Based on these findings, innovative 3D printed support structures with novel printed modifications, like conical holes instead of cylindrical holes or additional roofs above each hole, in comparison to the state-of-the-art stainless-steel perforated sheets, were developed and evaluated in this work. Especially for oleophilic filter media, where the oil film in quasi-steady state is build up on the filter rear side and thus, noticeably affected by support structures, the differential pressure was in some cases slightly reduced, whereas entrainment was significantly reduced (up to −75%) by the developed 3D printed support structures. For oleophobic filter media entrainment was mainly affected by the 3D printed support structures and was significantly reduced.