Drain Free Filtration (DFF)—A New CFF Technology

Hydro and Hycast have significant experience in using underpressure to lift liquid metal up from the level in the launders for metal refining and thereby avoiding drainage metal at the end of the cast. This is also utilized in the Drain Free Filtration (DFF) technology, a new Ceramic Foam Filter (CFF) technology that has been developed. Eliminating drainage metal is a cost factor as well as an advantage regarding safety. In a standard CFF box the metal flow direction during priming is the same as during filtration. With the DFF technology the filters are primed in the reverse direction, which gives several advantages when it comes to how well the priming is working and for the subsequent filtration efficiency. Tests with a prototype DFF box with 23″ filters have shown that priming of 80 ppi filters is working very well. Thus, the new technology will enable Hydro to produce high quality metal for critical products that will help our customers.