Method to make yarn-reinforced hollow fiber membranes around a soluble core
First Claim
1. A process of making a reinforced hollow fiber membrane, the process comprising:
- applying reinforcing filaments to a core while moving the core longitudinally;
casting a dope over the reinforcing filaments and the core;
forming a membrane from the dope;
removing the core; and
shrinking the reinforcing filaments before casting the dope over the reinforcing filaments.
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Accused Products
Abstract
Disclosed is the method for creating a reinforced hollow fiber membrane by applying reinforcing filaments to a core, casting a dope over the filaments and core, forming a membrane from the dope, and removing the core. The core may be a moving core, and the reinforcing yarns may comprise warp yarns and a spiral wrap yarn. The core may be soluble and removed by dissolving it. The core may be pre-wrapped with a yarn before the warp yarns are applied. The resulting reinforcing cage may be pre-shrunk before it is coated with a membrane dope. The pre-wrapped yarn may be removed, for example by dissolving it, after the reinforcing cage is coated. A precursor assembly for making a hollow fiber membrane is also provided.
166 Citations
16 Claims
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1. A process of making a reinforced hollow fiber membrane, the process comprising:
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applying reinforcing filaments to a core while moving the core longitudinally; casting a dope over the reinforcing filaments and the core; forming a membrane from the dope; removing the core; and shrinking the reinforcing filaments before casting the dope over the reinforcing filaments.
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2. A process of making a reinforced hollow fiber membrane, the process comprising:
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applying reinforcing filaments to a core while moving the core longitudinally; casting a dope over the reinforcing filaments and the core; forming a membrane from the dope; removing the core; wrapping the core with pre-wrap filaments before applying the reinforcing filaments to the moving core; and removing the pre-wrap filaments after casting the dope over the reinforcing filaments. - View Dependent Claims (3)
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4. A process of making a reinforced hollow fiber membrane, the process comprising:
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applying reinforcing filaments to a moving core; casting a dope over the reinforcing filaments and the core; forming a membrane from the dope; and removing the core, wherein the reinforcing filaments comprise warp filaments and wrap filaments. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A process of making a reinforced hollow fiber membrane, the process comprising:
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applying reinforcing filaments to a core while moving the core longitudinally; casting a dope over the reinforcing filaments and the core; forming a membrane from the dope; and removing the core, wherein the reinforcing filaments comprise a polymer that is soluble in the membrane dope. - View Dependent Claims (11)
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12. A process of making a reinforced hollow fiber membrane, the process comprising:
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applying reinforcing filaments to a core while moving the core longitudinally; casting a dope over the reinforcing filaments and the core; forming a membrane from the dope; and removing the core, subject to one or more of the following limitations;
a core outside diameter of 0.5 to 1.0 mm;
a membrane outside diameter to inside diameter ratio of 1.5 or more;
4 to 12 warp yarns, covering substantially the entire circumference of the core;
1 or 2 wrap yarns, at a pitch of 1.5 to 4.5 mm;
shrinking the reinforcing filaments before coating at a temperature of 100 degrees C. or more;
coating the dope at a temperature of 50 degrees C. or more;
coating the dope at a pressure of 20 psi or less; and
having a die opening diameter to core outside diameter ratio of 1.75 or less. - View Dependent Claims (13, 14, 15, 16)
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Specification