Rotary vacuum-drum filter
Encyclopedia
Rotary vacuum filter drum consists of a drum rotating in a tub of liquid to be filtered.

The technique is well suited to high solids liquids that would blind or block other forms of filter. The drum is pre-coated with a filter aid, typically of diatomaceous earth
Diatomaceous earth
Diatomaceous earth also known as diatomite or kieselgur/kieselguhr, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 1 micrometre to more than 1 millimetre, but typically 10 to...

 (DE) or Perlite
Perlite
Perlite is an amorphous volcanic glass that has a relatively high water content, typically formed by the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently...

. After pre-coat has been applied, the liquid to be filtered is sent to the tub below the drum. The drum rotates through the liquid and the vacuum sucks liquid and solids onto the drum pre-coat surface, the liquid portion is "sucked" by the vacuum through the filter media to the internal portion of the drum, and the filtrate pumped away. The solids adhere to the outside of the drum, which then passes a knife, cutting off the solids and a small portion of the filter media to reveal a fresh media surface that will enter the liquid as the drum rotates. The knife advances automatically as the surface is removed.

Further reading

  • John J. McKetta, John J. McKetta Jr, "Unit Operations Handbook: Mechanical separations and materials handling", CRC Press, 1992, pp.274-288. ISBN 082478670X
  • Hiroaki Masuda, Kō Higashitani, Hideto Yoshida, "Powder Technology: Handling and Operations, Process Instrumentation, and Working Hazards", CRC Press, 2006, pp.194-195. ISBN 1420044125

External links

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