HOLLOW FIBER MEMBRANE DEVICE AND METHOD OF FABRICATING SAME

• US 3,708,071 A
• Filed: 08/05/1970
• Issued: 01/02/1973
• Est. Priority Date: 08/05/1970
• Status: Expired due to Term

• Current Assignee: Koch Membrane Systems, Inc. (KOCH Industries Incorporated)
• Original Assignee: Richard P. Crowley
• Inventors: Crowley, Richard P.
• Primary Examiner(s): Spear, Jr., Frank A.
• Application Number:
  US05/061,307
• Time in Patent Office: 881 Days
• Field of Search: 210/22,23,321,500 55/16,158 264/41,49,258,177,277,274,200
• US Class Current: 210/321.8
• CPC Class Codes: B01D 63/021 Manufacturing thereof
• CPC Class Codes: B01D 63/022 Encapsulating hollow fibres
• CPC Class Codes: B01D 63/0221 using a mould
• CPC Class Codes: B01D 63/0233 forming the bundle
• CPC Class Codes: B29C 70/845 by moulding material on a relative small portion of the preformed parts

Abstract

A method for preparing one or more terminal headers containing capillary fibers encased therein for use in a membrane device. The ends or a loop portion of a plurality of capillary fibers are immersed in a foam material. The foam material sets, encasing the capillaries therein forming a header. The header is then severed, exposing the open ends of the capillaries.

Claims

1. In a method of preparing a membrane device wherein a plurality of hollow capillary fibers composed of a material to permit the separation by membrane permeation techniques of a feed stream into a permeate-lean and a permeate-rich fraction, the walls of the hollow fibers comprising the membrane material and dividing the device into a permeate zone and a feed zone are disposed with an outer shell and at least one header, which header is arranged in a fluid-tight manner to the interior wall of the outer shell, the open ends of the fibers in the headers exposed on one surface thereof to permit the introduction into or the withdrawal from the interior of the exposed ends of the fibers of a fluid stream, the improvement which comprises:

a. encasing the hollow fibers in a header material, which material comprises at least in part a first layer of cellular material;

b. encasing the hollow fibers in a second layer of solid polymeric material to provide a fluid-tight seal between the exterior walls of the hollow fibers and the polymeric material; and

c. severing the fibers encased in the cellular layer to expose the open ends of the hollow fibers in that layer, thereby inhibiting damage to the hollow fibers and enhancing the ease of severing of the fibers during the severing operation.

2. The method of claim 1 which includes encasing the hollow capillary fibers in a semirigid polymeric cellular material substantially composed of noninterconnecting closed cells, the cellular material forming a fluid-tight seal between the exterior walls of the fibers to prevent the passage of material through the interstices between the fibers.

3. The method of claim 1 which includes encasing the hollow fibers in a flexible polymeric cellular material and exposing the open ends of the fibers along a single plane in the cellular plane by cutting the hollow fibers in the cellular plane.

4. The method of claim 1 which includes encasing the hollow fibers in a cellular material selected from the group of polymeric material consisting of urethane resins, vinyl halide resins, olefinic resins and silicone resins.

5. The method of claim 1 which includes encasing the hollow fibers in the cellular material prior to treating the exterior walls of said hollow fibers to be placed in the said material with a bonding agent to secure an enhancement in bonding strength between the exterior walls of the hollow fibers and the cellular material.

6. The method of claim 1 which includes encasing one portion of the hollow fibers in a liquid hardenable resin material and an adjoining portion in a liquid gas-expandable resin material;

and thereafter, hardening the liquid hardening material to form a fluid-tight seal between the exterior walls of the hollow fibers in said hollow hardened material; and

expanding and hardening the gas-expandable material to form a plane of cellular material bonded to and adjacent the solid material.

7. The method of claim 1 which includes encasing the hollow fibers in a flexible cellular material which extends at least slightly beyond the external perimeter of the hollow fibers and thereafter, encasing the cellular header so formed within the outer shell, the external portion of the cellular material being in sealing contact with the interior wall of the outer shell.

8. The method of claim 1 which includes encasing opposing ends of substantially parallel hollow fibers in a header material, which material comprises in part a plane of cellular material and severing the cellular material and the hollow fibers so as to provide for the exposed ends of the hollow fibers at each opposing surface of the headers so formed, and thereafter, securing said headers within an outer shell to form a membrane device.

9. The method of claim 1 which includes immersing the hollow capillary fibers in a polymeric foam material, hardening the foam material about the exterior walls of the hollow fibers to form a plane of cellular material, and thereafter, cutting the hollow fibers in said plane of cellular material to expose the open ends thereof.

10. The method of claim 1 wherein the cellular material is a flexible or semirigid cellular material, the header consisting essentially of such cellular material and the fibers.

11. The method of claim 1 wherein the capillary fibers and cellular material are selected and adapted for use in an artificial kidney device.

12. A method of fabricating a header suitable for use in a membrane device, which header contains embedded therein a plurality of hollow capillary fibers and which method comprises:

a. inserting a plurality of the hollow capillary fibers into a multicomponent liquid polymeric material, one of which materials is a gas-expandable polymeric material adapted to form a cellular material and to enable the hollow fibers to be cut, and the other liquid material containing a hardenable polymeric material adapted to form a fluid-tight seal with the exterior walls of the hollow fibers;

b. expanding and hardening the polymeric material to form a cellular material and a solidified hardened polymer containing the hollow fibers therein; and

c. exposing the ends of the hollow fibers while contained in the cellular material, thereby producing a header, one surface of which contains exposed ends of hollow fibers, while the hollow fibers are embedded in the cellular material and sealed with the solidified polymer.

13. The method of claim 12 which includes inserting a hank containing a plurality of hollow capillary fibers into the liquid polymeric material and exposing the ends of the hollow fibers by severing the hank in the cellular polymeric material, thereby providing a header containing cellular materials with substantially parallel hollow fibers embedded therein.

14. In a capillary membrane unit having an outer shell, a plurality of capillary fibers disposed within the shell, the walls of the capillary fibers defining a feed zone and a permeate zone, a feed inlet for the introduction of a fluid stream, an outlet for the withdrawal of a permeate-lean stream, and an outlet for the withdrawal of a permeate-rich stream, the improvement which comprises:

a. a header, which includes an exposed surface, comprising a polymeric foam material disposed within the shell, the header adapted for sealing engagement with the interior wall of the shell, the capillary fibers embedded in said foam material, said fibers having exposed ends lying in substantially the same plane as said exposed surface, the header comprising first and second layers, the first layer comprising the polymeric foam material, and the second layer comprising a solid sealing layer of resinous material, said resinous material forming a sealing relationship between the exterior wall portions of the fibers and said foam material.

15. The device of claim 14 wherein the capillary fibers are in a substantially parallel relationship.

16. The device of claim 14 which includes first and second headers disposed at either ends of the capillary fibers.

17. The device of claim 14 wherein the header defines in combination with the internal wall of the shell, a feed inlet chamber upstream of the exposed ends of the capillary fibers.

18. The device of claim 14 which includes first and second headers disposed at either ends of the capillary fibers and wherein the first header defines in combination with the interior wall of the shell a feed chamber in communication with the open ends of the capillaries, and wherein the second header defines in combination with the internal wall of the shell an outlet chamber, the exposed ends of the capillary fibers in said second header in communication with said outlet chamber.

19. The device of claim 14 wherein the foam material is a closed-cell foam material.

20. The device of claim 19 wherein the closed-cell foam comprises an RTV silicone rubber.

21. The device of claim 14 wherein the foam material comprises an open-cell foam material.

22. The device of claim 14 wherein the sealing layer comprises a closed-cell material.

23. The device of claim 14 wherein the foamed layer comprises a blown open-cell vinyl resin and the second layer comprises a nonblown vinyl chloride resin.

24. The device of claim 14 wherein the foamed material is a RTV silicone rubber.

25. The device of claim 14 wherein the foamed layer extends beyond the outer periphery of the capillaries to provide a sealing engagement with the interior wall of the shell.

26. The device of claim 14 wherein the foam material is a flexible or semirigid foam material, the header consisting essentially of such foam material.