Responsive gels and methods of use thereof
AssigneeFoster-Miller, Inc.
InventorsElmer C. Lupton, Thomas H. E. Mendum, R. Edwin Hicks, Leslie S. Rubin, Justyna B. Teverovsky, Harris Gold
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Abstract
The present invention provides variable pore size filters. The variable pore size filters of the present invention comprise a fabric matrix, having a set pore size, wherein the fabric matrix is coated with a gel that expands and shrinks in response to a trigger. When the gel is expanded, the pore size of the filter is small and filtering is accomplished. When the gel is shrunken, the pore size of the filter is large and cleaning of the filter by a backwash or forward flush of fluid is accomplished.
Claims20
A process for filtering seawater comprising:
- (a) providing a filter system comprising a substrate and a responsive gel, wherein responsive gel is hydroxypropylcellulose (HPC) or hydroxypropyl methyl cellulose (HPMC),
- the substrate having a predetermined permeability, and the responsive gel coating or impregnating the substrate,
- wherein the responsive gel is coated or impregnated such that shrinkage and expansion of the gel in response to a change in environmental condition alters the permeability of a fluid through the filter system;
- (b) causing the responsive gel to expand so as to decrease the permeability of a fluid through the filter system;
- (c) passing seawater through the filter system to entrap or filter particles from the seawater;
- (d) causing the responsive gel to shrink so as to increase the permeability of a fluid through the filter system;
- (e) removing or cleaning the entrapped particles from the filter system by passing water through the filter system;
- and
- (f) optionally repeating steps (b)-(e) one or more times.
A filter system for filtering seawater comprising:
- a substrate comprising a matrix, mesh, or reticulated foam having pores, the pores having a first pore size and providing a predetermined permeability;
- and
- a responsive gel having reversible expanded state and a collapsed state, the responsive gel coating or impregnating the substrate to close off the pores to some extent, wherein the responsive gel is hydroxypropylcellulose (HPC) or hydroxypropyl methyl cellulose (HPMC),
- wherein the expanded responsive gel provides an expanded pore size less than the first pore size, and the collapsed responsive gel provides a collapsed pore size greater than the expanded pore size and less than the first pore size,
- wherein the responsive gel collapses and expands reversibly in response to a change in environmental condition to provide a variable pore size ranging between the collapsed pore size and the expanded pore size.
Dependencies are inferred from the claim text.