Continuous Precoat Vacuum Filter

Rotary Drum Vacuum Filter are used extensively in the processing of chemicals, pharmaceuticals, cosmetics, foods, minerals and in wastewater treatment and sludge dewatering for industry and municipalities. RDVFs are extremely versatile and provide reliable, continuous liquid/solid separation with minimum operator attention and low maintenance.

The precoat filter is used when direct filtration against a cloth medium is not possible because the cake cannot be removed from the cloth or when blinding is indicated.

A uniform vacuum is applied to the drum surface and the filter is coated initially with a layer of diatomaceous earth, perlite, cellulose, carbon or a combination there of. A woven filter medium retains the precoat solids up to 4” thick ( Special designs allow for a 6” thick precoat). The thicker the precoat layer the longer the operating period before reapplication is necessary. As the feed slurry is filtered, the solids are retained on the surface of the precoat layer. On each revolution, an advancing stellite knife shaves off the deposited solids and a 0.01”-0.06” thick layer of precoat per drum revolution. Removing a thin layer of precoat with each revolution renews the filtration surface and optimizes filtration rates.

The advance rate of the knife can be infinitely adjusted for maximum filtration rates and minimum precoat usage.

Where to use

For slimy sticky, oily and blinding solids.

For clear filtrates.

For filtering dilute slurries with varying feed concentrations.

For the discharge of very thin filter cakes.