Asymmetric hollow fiber membranes
First Claim
Patent Images
1. A membrane comprising:
- a porous asymmetric hollow polymer fiber having an inside porous surface having a coarse porous structure and an outside porous surface having a dense porous structure, the average pore size rating of the pores on the inside surface being greater than the average pore size rating of the pores on the outside surface.
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Abstract
A porous asymmetric hollow polymer fiber membrane having an inside surface having a coarse porous structure and an outside surface having a dense porous structure, the average pore size rating of the pores at the inside surface being greater than the average pore size rating of the pores at the outside surface, as well as filters and filter devices comprising one or more of the hollow fiber membranes, the filter and devices preferably being arranged to direct fluid flow from the inside surface of the membranes to the outside surface, and methods of using the filters and filter devices, are disclosed.
95 Citations
35 Claims
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1. A membrane comprising:
a porous asymmetric hollow polymer fiber having an inside porous surface having a coarse porous structure and an outside porous surface having a dense porous structure, the average pore size rating of the pores on the inside surface being greater than the average pore size rating of the pores on the outside surface. - View Dependent Claims (2, 7, 8, 9, 10, 11)
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3. A filter comprising two or more porous asymmetric hollow polymer fiber membranes, each membrane having an inside porous surface having a coarse porous structure and an outside porous surface having a dense porous structure, the fiber membrane having a progressively asymmetric structure from the inside surface to the outside surface.
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4. A filter device comprising:
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a housing having an inlet and an outlet and defining a fluid flow path between the inlet and the outlet, and a plurality of porous asymmetric hollow polymer fiber membranes disposed across the fluid flow path, each porous asymmetric hollow fiber membrane having an inside surface having a coarse structure and an outside surface having a dense structure, the average pore size rating of the pores on the inside surface being greater than the average pore size rating of the pores on the outside surface;
wherein the housing is arranged to direct fluid from the inlet, through the inside surface and the outside surface of the porous asymmetric hollow fiber membranes, and through the outlet.
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5. A filter device comprising:
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a housing having an inlet, a first outlet and a second outlet, the housing defining a first fluid flow path between the inlet and the first outlet, and a second fluid flow path between the inlet and the second outlet;
a plurality of porous asymmetric hollow polymer fiber membranes disposed across the first fluid flow path and substantially parallel to the second fluid flow path, each porous asymmetric hollow fiber membrane having an inside surface having a coarse structure and an outside surface having a dense structure, the average pore size rating of the pores on the inside surface being greater than the average pore size rating of the pores on the outside surface;
wherein the housing is arranged to direct a permeate from the inlet, through the inside surface and the outside surface of the porous asymmetric hollow fibers, and through the first outlet, and direct a retentate from the inlet, substantially tangentially to the inner surface, and through the second outlet. - View Dependent Claims (6)
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12. A method for processing a fluid suspension comprising:
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providing at least one porous asymmetric hollow polymer fiber membrane having an inside porous surface having a coarse structure and an outside porous surface having a dense structure, the average pore size rating of the pores on the inside surface being greater than the average pore size rating of the pores on the outside surface;
contacting the inside surface of the membrane with a fluid suspension comprising undesirable cellular material and a macromolecule of interest, and passing the macromolecule of interest from the inside surface to the outside surface while retaining undesirable material between the inside and outside surfaces. - View Dependent Claims (13, 14, 17, 33)
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15. A method of separating a fluid into a retentate and a permeate comprising:
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directing a feed suspension comprising larger macromolecules and smaller macromolecules into the central bore of a hollow fiber membrane, the membrane having an inside porous surface having a coarse structure and an outside porous surface having a dense structure, the average pore size rating of the pores at the inside surface being greater than the average pore size rating of the pores at the outside surface;
passing a permeate containing the smaller macromolecules from the inside surface to the outside surface; and
passing a retentate containing the larger macromolecules through the central bore of the membrane.
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16. A method of separating a fluid into a retentate and a permeate comprising:
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directing a feed suspension comprising larger species and smaller species into the central bore of a hollow fiber membrane, the membrane having an inside porous surface having a coarse structure and an outside porous surface having a dense structure, the average pore size rating of the pores at the inside surface being greater than the average pore size rating of the pores at the outside surface;
passing a permeate containing the smaller species from the inside surface to the outside surface; and
passing a retentate containing the larger species through the central bore of the membrane.
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18. A method of preparing an asymmetric hollow fiber membrane comprising:
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providing a spinning dope comprising a first polymer, a solvent, and a nonsolvent, in ratios sufficient to form a homogenous solution or a colloidal dispersion;
extruding the dope in the form of a hollow pre-fiber from a nozzle, the pre-fiber having an inside surface and an outside surface;
contacting the outside surface of the pre-fiber with a coagulating medium; and
coagulating the pre-fiber from the outside surface to the inside surface to provide an asymmetric hollow fiber membrane. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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34. A method for cleaning a hollow fiber membrane having an outside porous surface, an inside porous surface, and a bore comprising:
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passing a fluid from the outside porous surface of the hollow fiber membrane to the inside porous surface of the membrane, the inside surface of the membrane having larger average pore size rated pores than the outside surface; and
,passing the fluid from the inside surface of the membrane along the bore of the membrane. - View Dependent Claims (35)
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Specification