Method of drying a material having a cohesive phase
AssigneeGenzyme Corporation
InventorGary S. Rea
Life of this patent
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Abstract
A method for drying a material such as a polymer hydrogel which passes through a cohesive phase as it dries is disclosed. The method comprises agitating a composition while removing liquid until the solids content of the composition reaches a level at which the composition enters a cohesive phase, halting agitation, removing liquid from the composition in the absence of agitation, and resuming agitation. Practice of the present invention can eliminate the problems associated with adhesion of a material to itself and to process equipment during the cohesive phase.
Claims14
A method of removing liquid from a composition that comprises a polymer hydrogel, the method comprising:
- (a) agitating the composition while removing liquid until the composition enters a cohesive phase;
- (b) halting agitation;
- (c) removing liquid from the composition in the absence of agitation until the composition passes through the cohesive phase;
- and
- (d) resuming agitation, wherein:
- i) the composition is agitated at a pressure P1 and the liquid is removed from the composition in the absence of agitation at a pressure P2;
- ii) P2 is less than P1;
- iii) P1 is about 25 to 500 mbar absolute;
- and
- iv) P2 is less than about 100 mbar absolute.
Dependencies are inferred from the claim text.