Frameless array of hollow fiber membranes and method of maintaining clean fiber surfaces while filtering a substrate to withdraw a permeate
First Claim
1. A membrane device, for withdrawing permeate from a multicomponent liquid substrate, comprising,means for providing an alternative to a conventional module having plural individual arrays therewithin, includinga frameless array of a multiplicity fiber membranes, or fibers, for operation without being supported except by said substrate, and without being confined in a shell of a module, said fibers together having a surface area >
- 1 m2, said fibers being buoyantly swayable in said substrate, said fibers providing a transmembrane pressure differential in the range from about 0.7 kPa (0.1 psi) to about 345 kPa (50 psi), and each having a length >
0.5 meter;
a pair of first and second headers disposed in spaced-apart relationship within said substrate so that said fibers, when deployed, present an arcuate configuration above a horizontal plane through the horizontal center-line of a header;
said first header having a terminal end portion of each fiber secured therein, and a second header having an opposed terminal end portion of each fiber secured therein, all said fibers extending from a face of each said header and essentially all said fibers being open at their ends so as to discharge said permeate through each of said headers;
said fibers being sealingly secured with open ends of the fibers secured in fluid-tight relationship with each other in each of said headers;
liquid collection means to collect said permeate, connected in open fluid communication with said lower face of each of said headers; and
,means to withdraw said permeate.
3 Assignments
0 Petitions
Accused Products
Abstract
A frameless array unconfined in a modular shell, proves to be a surprisingly effective membrane device for withdrawing permeate from a substrate, the flux through the membranes reaching an essentially constant relatively high value because of the critical deployment of fibers of the array as a skein, arching in a buoyantly swayable generally parabolic configuration within the substrate, above at least one of the array'"'"'s headers in which the terminal end portions of the fibers are potted. The length of each fiber must be greater than the direct center-to-center distance between the array'"'"'s pair of headers. For use in a large reservoir, an assembly of the array and a gas distributor means has fibers preferably >0.5 meter long, which together provide a surface area >10 m2. The terminal end portions of fibers in each header are substantially free from fiber-to-fiber contact. When used in a tank from which the permeate is withdrawn at a location low enough to overcome the transmembrane pressure differential of the fibers, the permeate is withdrawn under a vacuum induced by gravity. To increase flux, a pump may be used which provides a suction less than 75 cm of Hg. When used in combination with a gas-distribution manifold disposed beneath the skein so as to flow bubbles through it, the surfaces of the fibers are surprisingly resistant to being fouled by build-up of deposits of inanimate particles or microorganisms in the substrate. Membranes with high transmembrane pressure differential may be used, if desired, and permeate removed with a vacuum pump.
269 Citations
24 Claims
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1. A membrane device, for withdrawing permeate from a multicomponent liquid substrate, comprising,
means for providing an alternative to a conventional module having plural individual arrays therewithin, including a frameless array of a multiplicity fiber membranes, or fibers, for operation without being supported except by said substrate, and without being confined in a shell of a module, said fibers together having a surface area > - 1 m2, said fibers being buoyantly swayable in said substrate, said fibers providing a transmembrane pressure differential in the range from about 0.7 kPa (0.1 psi) to about 345 kPa (50 psi), and each having a length >
0.5 meter;a pair of first and second headers disposed in spaced-apart relationship within said substrate so that said fibers, when deployed, present an arcuate configuration above a horizontal plane through the horizontal center-line of a header; said first header having a terminal end portion of each fiber secured therein, and a second header having an opposed terminal end portion of each fiber secured therein, all said fibers extending from a face of each said header and essentially all said fibers being open at their ends so as to discharge said permeate through each of said headers; said fibers being sealingly secured with open ends of the fibers secured in fluid-tight relationship with each other in each of said headers; liquid collection means to collect said permeate, connected in open fluid communication with said lower face of each of said headers; and
,means to withdraw said permeate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- 1 m2, said fibers being buoyantly swayable in said substrate, said fibers providing a transmembrane pressure differential in the range from about 0.7 kPa (0.1 psi) to about 345 kPa (50 psi), and each having a length >
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10. A gas-scrubbed assembly comprising, means for providing an alterative to a conventional module having plural individual arrays therewithin, including,
a membrane device in combination with a gas-distribution means, to minimize build-up of particulate deposits on the surfaces of hollow fiber membranes in said device, and to recover permeate from a multicomponent liquid substrate, said assembly comprising, a frameless array of a bundle of said hollow fibers in a skein which is unsupported for operation in said substrate held at a pressure in the range from 1-10 atm, without being confined in a module'"'"'s shell, the ends of said fibers being secured in first and second headers adapted to be mounted in spaced-apart relationship within said substrate and beneath said skein which is buoyantly swayable in said substrate, said first header having terminal end portions of a multiplicity of fibers sealingly secured in said first header, and said second header having opposed terminal end portions of said fibers sealingly secured in said second header, essentially all ends of said fibers being open so as to discharge permeate through said headers; -
said bundle comprising a multiplicity of fibers sealingly secured in closely-spaced-apart profusion and sealed with potting resin; liquid collection means secured in fluid-tight open communication with permeate-discharging faces of said headers;
means for mounting said headers and liquid collection means for operation in said substrate;said gas-distribution means, located within a zone directly beneath said skein, having through-passages therein adapted to have sufficient gas flowed therethrough to generate enough bubbles flowing through said skein and around said fibers, so as to keep surfaces of said fibers awash with bubbles; and
, means for withdrawing said permeate. - View Dependent Claims (11, 12, 13, 14)
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15. A system for withdrawing permeate from a multicomponent liquid substrate having particulate matter suspended therein, with a gas-scrubbed assembly comprising a frameless array of hollow fiber membranes (or "fibers") in combination with a gas-distribution means, said system comprising, means for providing an alterative to a conventional module having plural individual arrays therewithin, including,
a reservoir for a volume of at least 100 liters of said substrate from which a permeate is to be withdrawn; -
a pair of headers adapted to be mounted in spaced-apart relationship within said substrate without being confined in a modular shell, a first header having terminal end portions of a multiplicity of fibers secured therein, and a second header having opposed terminal end portions of said fibers secured therein, essentially all ends of said fibers being open so as to discharge permeate through said headers, at least one header being disposed below a horizontal plane through the horizontal center plane of said one header; said fibers formed from a material selected from the group consisting of an inorganic material and an organic synthetic resinous material, and swayably buoyantly deployed in a body of said substrate, said fibers together having a surface area in excess of 10 m2, each fiber having a length >
0.5 m and sufficiently greater than the direct distance between said first and second headers, so as to present, when said skein is deployed, a generally arcuate configuration above a plane through the horizontal center-line of a headers;collection means for collecting said permeate; means for mounting said spaced-apart headers in open fluid communication with said collection means; means for withdrawing said permeate; and
,said gas-distribution means disposed within a zone beneath said skein, and adapted to generate bubbles which flow upwardly through said skein, whereby said fibers are kept awash in bubbles and resist the build-up of said particulate matter on the surfaces of said fibers. - View Dependent Claims (16, 17, 18)
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19. A process for maintaining the outer surfaces of hollow fiber membranes essentially free from a build-up of deposits of particulate material while separating a permeate from a multicomponent liquid substrate in a reservoir, said process comprising, providing an alternative to a conventional module having plural individual arrays therewithin, by
submerging a frameless array of fibers deployed as a skein within said substrate unconfined in a modular shell, said fibers being securely held in laterally opposed, spaced-apart first and second headers, said fibers having a transmembrane pressure differential in the range from about 0.7 kPa (0.1 psi) to about 345 kPa (50 psi), a total surface area > - 1 m2, and a length sufficiently greater than the direct distance between said first and second headers, so as to present said skein in a buoyantly swayable generally arcuate fiber configuration above a horizontal plane through the horizontal center-line of a header;
mounting said headers in fluid-tight open communication with collection means to collect said permeate; flowing a fiber-cleansing gas through a gas-distribution means proximately disposed relative to said skein, within a zone directly beneath said skein, and contacting surfaces of said fibers with sufficient physical impact of bubbles of said gas to maintain essentially the entire length of each fiber in said skein awash with bubbles and essentially free from said build-up; maintaining an essentially constant flux through said fibers substantially the same as an equilibrium flux initially obtained after commencing operation of said process; collecting said permeate in said collection means; and
, withdrawing said permeate. - View Dependent Claims (20, 21, 22, 23, 24)
- 1 m2, and a length sufficiently greater than the direct distance between said first and second headers, so as to present said skein in a buoyantly swayable generally arcuate fiber configuration above a horizontal plane through the horizontal center-line of a header;
Specification