Essay on Aspects of Rotary Vacuum Filter Design and Performance

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Aspects of Rotary Vacuum Filter Design & Performance
Associate Technical Editor’s Comments: This paper provides a cursory description of the various rotary vacuum filter designs and their applications, enumerates the operating adjustments for each type of discharge, details the optimum performance criteria for precoat filters and examines the basic requirements for the auxiliary equipment. This paper was presented at the 1999 annual meeting of the American Filtration and Separation Society which was held in Boston. Author: Gene Haug, Eagle-Picher Minerals, Inc.

The rotary vacuum filter is very basic in design, application and operation. It is also an extremely effective solid/liquid separation device due to its unique methods
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This can cause environmental problems, vacuum pump operation problems and a loss of filtered product. By adding a second receiver with a diameter sufficient to reduce the air flow velocity to 1 ft/sec (or less), most foam can be dropped out of the air stream. Foam carry-over can also be eliminated by reducing the filter operating vacuum level. However, this will reduce the filter throughput and increase operating costs, especially with a precoat discharge filter (Figure 13). Tilting Vat One manufacturer offers a “tilting vat” design which provides a means of reducing the “dead” time between the knife blade at point of discharge and the drum as it enters the slurry. The vat is horizontal when filtering at “high” drum submergence and progressively “tilted” as the drum submergence (vat level) decreases. Two other notable design features of this filter are that: the knife is attached to the vat, which moves back and forth, in order to produce knife advance or retraction; as with some other European designs, the filter does not have a vat agitator (Figure 14). Page | 2 Article reprinted from Fluid/Particle Separation Journal, Vol. 13, No. 1, April 2000

Hydraulic Agitator Some European filter manufacturers eliminate the “rake” style vat agitator and use the hydraulics of a