Four BoVac Drum drum filters are operated for filtration, washing and dewatering of fine sized tarnishing pigments. Each of these modern 5 m² vacuum drum filters replaces one 8 m² drum filter of old design. The filters are equipped with adjustable wash bars with spray nozzles and with a wash hood. Cake wash achieves a reduction of conductivity in the filter cake from 42.000 µS down to 180 µS after cake wash.

Exchangeable filter cells allow easy cleaning and incomparable quick re-clothing. With a second set of filter cells already equipped with filter bags the time for re-clothing is only approx. 1–2 hours, including shutdown, cleaning and restart of the filter.