Process for removing cellulose ethers from a cellulose ether suspension
OwnerGuenther Just, Willi Wuestinventors
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Abstract
A process is disclosed for recovering a cellulose ether from a cellulose ether suspension in which the cellulose ether is recovered as a filter cake from a pressure filtration, particularly using a rotary pressure filter. Clogging of the separation or filtration device is avoided, providing for a long useful life. A multi-layer wire mesh filter medium is employed, formed of mesh layers of different wire thicknesses and/or mesh size. After removal of the filter cake, the filter medium is cleaned with steam, compressed air or pressurized water.
Claims20
In a process for removing cellulose ethers from a cellulose ether particle suspension in which the cellulose ethers are recovered as a filter cake from a pressure filtration, the improvement wherein said pressure filtration is conducted in a rotary pressure filter containing a multi-layered wire mesh filter medium comprised of mesh layers having different mesh sizes wherein said filter medium comprises a multi-layer square-opening mesh, linen-bonded to a filter cloth with at least one protective mesh on each side and wherein said filter cloth has a mesh size corresponding to about the mean particle diameter size of the cellulose ether suspension particles and, subsequent to removal of said filter cake from said filter medium, said filter medium is cleaned with steam, compressed air or water under pressure.
A process for removing a cellulose ether from an aqueous cellulose ether suspension comprising (1) pressure filtering said suspension in a rotary pressure filter containing a filter medium, said filter medium comprising a multi-layered, square-opening wire mesh, linen-bonded to a filter cloth with at least one protective wire mesh on each side of said filter cloth, the upper layer protective wire mesh having a mesh size about 3 times that of said filter cloth and the lower protective wire mesh layer having a mesh size about 5 times that of said filter cloth, said filter medium further comprising a supporting wire mesh layer having a wire mesh about 13 times that of said filter cloth, said filter cloth having a mesh size corresponding to about the mean particle size diameter of the cellulose ether suspension particles;
- (2) washing the filter cake resulting from said filtering step (1) with hot water or steam;
- (3) loosening said filter cake from said filter medium by back-blowing with steam or compressed air;
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- (4) removing said filter cake from said filter medium.
A multi-layered wire mesh filter medium for pressure filtration of an aqueous cellulose ether particle suspension to recover a cellulose ether comprising a multi-layer mesh linen-bonded to a filter cloth with at least one protective wire mesh on each side of said filter cloth, the upper protective wire mesh layer having a mesh size about five times that of said filter cloth, said filter medium further comprising a supporting wire mesh layer having a stainless steel wire mesh about thirteen times that of said filter cloth, said filter cloth having a mesh size corresponding to about the mean size diameter of the cellulose ether suspension particles.
Dependencies are inferred from the claim text.