Filtration solution for highly viscous media such as bitumen

Industrial filtration of highly viscous media gives rise to problems that conventional filters cannot solve. Contec accepted the challenge and found a successful filtration solution for highly viscous media such as bitumen in the manufacture of cold self-adhesive vapor barriers for large-area roofs.

The challenge:

• Medium: polymeric bitumen
• Product: cold-adhering thin-film bituminous sheeting for roofs larger than 2,500 m² at a thickness of 0.3 mm
• Temperature: 130 °C
• Viscosity at 130 °C: about 100,000 mPaS
• Viscosity at 140 °C: about 45,000 mPaS

Layers this thin necessarily pose production problems. A layer of polymeric bitumen ≥0.3 mm thick is applied to a plastic-laminated carrier film at 140 °C. To avoid disruptions due to clumping during the production process, the hot polymeric bitumen paste must be filtered. Because the paste's viscosity rises as temperature falls, the filter can be disassembled and maintained only when it is hot.

The solution:

The hot bitumen paste is filtered with a newly developed Contec wedge wire filter with a hinged cover and interior spring-loaded coupling. The filter is also equipped with a heat jacket that allows it to be integrated into the existing factory-manufactured thermal oil system. With this design, the filter element can be disassembled without tools at full operating temperature. The filter reliably eliminates clumping and production runs smoothly. The Contec wedge wire filter is especially useful for filtration of highly viscous, abrasive or sticky liquids.