Method of operating a centrifugal filter and a filter centrifuge operating according to this method
AssigneeKrauss-Maffei Aktiengesellschaft
InventorsGunther Hultsch, Kurt Zeppenfeld, Peter Niedner, Peter Ostermeyer
Life of this patent
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Abstract
A method of operating a filter centrifuge or centrifugal filter in which a hydrostatic head is provided at the filtering surface so as to control liquid passage therethrough. The head may promote movement of the liquid through the filter layer or may induce reverse flow of liquid for backwashing or rinsing. In addition, a hydrostatic balance may be provided at this surface through control of the head to limit passage of the liquid through the filter layer. Preferably the head provides a suction augmenting centrifugal filtration.
Claims22
A method of oeprating a filter centrifuge comprising a centrifuge drum rotatable about a horizontal axis and formed with a filter medium upon which a filter cake is adapted to form, said drum being surrounded by a liquid-collecting compartment having at least one outlet, said method comprising the steps of:
- rotating said drum about said horizontal axis at a rate sufficient to induce passage of a liquid phase of a suspension outwardly through said filter medium into said liquid-collecting compartment;
- preventing entry of gas into said liquid-collecting compartment;
- applying a suction pressure head to said liquid-collecting compartnent;
- and
- pumping air by suction from said liquid-collecting compartment and filling same with liquid prior to passage of the liquid phase of said suspension through said filter medium to establish a liquid continuum in said liquid-collecting compartment extending substantially to said filter medium, said suction pressure head being formed by siphone draining of said compartment through an outlet radially outwardly of said filter medium with respect to said axis, the liquid in said compartment blocking entry of air.
A filter centrifuge comprising:
- a housing;
- a drum rotatable in said housing and formed with a support for a filter medium centered on a horizontal axis of rotation of the drum and adapted to accumulate a filter cake upon introduction of a suspension of solids in a liquid phase into said drum;
- first means forming a liquid-collecting compartment outwardly of said filter medium and provided with at least one outlet radially outwardly of said filter medium;
- second means for preventing entry of gas into said liquid-collecting compartment except for entry through said filter medium;
- and
- third means for inducing a suction pressure head at said filter medium in said liquid-collecting compartment, said second means being a siphon-like arrangement consisting of a liquid-containing part of said liquid-collecting compartment, a liquid-containing section of a further compartment, said section having at least one inlet radially outwardly of said filter medium, said inlet communicating with said outlet, and means for creating and maintaining in said further compartment a certain liquid level at a location radially inwardly of said inlet, the liquids in both of said compartments forming a liquid continuum, said further compartment being annular and being carried by said drum, said means for creating and maintaining said certain liquid level including an annular weir lying radially inwardly of said inlet.
Dependencies are inferred from the claim text.