Liquid purification or separation – Casing divided by membrane into sections having inlet – Each section having inlet
Reexamination Certificate
2001-05-25
2003-11-11
Walker, W. L. (Department: 1723)
Liquid purification or separation
Casing divided by membrane into sections having inlet
Each section having inlet
C210S321790, C210S321800, C210S321880, C210S321890, C210S323100, C210S323200
Reexamination Certificate
active
06645381
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to improvements in hollow membrane or hollow fiber cartridge assemblies, and more particularly to a modular assembly for releasably retaining such cartridges in an operative configuration within a reaction chamber. Hollow membrane fibers have particular utility in filtration, including ultra-filtration as well as in reverse osmosis applications. The modular assembly of the present invention includes an assembly with a reaction chamber particularly adapted for use in connection with fluid (gas or liquid) separation cartridges, with particular application to fluid separation cartridges within a vacuum chamber and with selective permeability to selected fluids. Specifically, the modular assembly of the present invention permits simultaneous utilization of any desired number of cartridges operating in parallel, each containing hollow membrane or hollow fibers, preferably porous, thereby providing for a plurality of such cartridges arranged and configured in modular form within a single reaction chamber which is held at a desired absolute pressure, and wherein each of the cartridges are individually and readily accessible. In this modular arrangement and assembly, individual cartridges may be installed, replaced, exchanged, as required for the given application.
As indicated above, hollow fibers and membranes have been employed for a variety of applications, with examples of such fibers and applications being shown in U.S. Pat. Nos. 4,806,246 and 5,824,444, as well as in application Ser. No. 08/824,302, filed Mar. 26, 1997, entitled “GAS SEPARATION USING HOLLOW FIBER CONTAINED LIQUID MEMBRANE”, Sirkar et al., all of which are assigned to the assignee of the present invention, and with the subject matter of each being incorporated by reference herein. Such hollow fibers typically have a continuous lumen disposed along the axis of the fiber, with the walls being porous, and with the outer wall having a coating thereon as defined in U.S. Pat. Nos. 4,806,246 and 4,824,444, and application Ser. No. 08/824,302 hereinabove.
SUMMARY OF THE INVENTION
For these applications, hollow fibers are typically arranged or configured within bundles, and such bundles are then operatively arranged in a cylindrical shell with appropriate access or ports being provided for the operative ends of the individual cartridges (see U.S. Pat. No. 4,824,444). In this connection, access to the lumens within the individual fibers is obtained through inlet and outlet manifolds disposed within the caps forming cartridge end chambers.
In a typical operative embodiment, feed fluids are delivered to the inlet manifold of the chamber, and thereafter passed through fiber lumens. The walls of the cartridges or sleeves in which the individual fibers are retained are typically perforated in a reticulated pattern to expose the feed fluid to the sweep fluid present within the reactivity zone of the chamber. In certain instances, a selected liquid or gas is passed through the reactivity chamber or zone, or alternatively, the zone may be maintained at a reduced pressure or to a vacuum state.
In connection with the operations typically utilizing the modular assembly of the present invention, a fluid is treated under pressure (feed pressure) at least sufficient to transport the fluid through the fiber lumens where components of the fluid, either liquid or gaseous, are separated through a membrane permeable to the component being separated. The feed pressure is appropriate for the properties of the fluids being handled, as well as being selected to be within the operating parameters of the individual fibers and membrane.
An assembly or system fabricated in accordance with the present invention is useful for a wide variety of applications, the following being typical of such applications:
1. Pervaporation, particularly with lumen feed;
2. Supported liquid membranes:
(a) liquid/liquid extraction metals or valuable chemicals;
(b) gas separations or waste water treatment (feed and sweep or feed and vacuum);
(c) facilitated transport;
3. VOC/gas separations, particularly with lumen feed;
4. hollow fiber contained liquid membranes;
5. supported liquid membrane pervaporation; and
6. membrane distillation or osmotic membrane distillation.
During typical operational applications, failure of one or more fibers within a bundle may require prompt replacement. The system of the present invention permits the replacement of the cartridge containing the damaged fiber without disturbing and/or replacing the remaining cartridges. Such module replacement may be undertaken on an expedited basis, thereby requiring removal of only one modular vessel from an operative system.
In any typical operative embodiment, individual cartridges require replacement from time to time. Replacement is indicated when individual fibers become exhausted, ruptured or damaged for one reason or another. For example, the expected lifetime of the fibers may expire, thereby requiring general replacement of all cartridges. The modular assembly of the present invention provides an expedient for exchanging individual cartridges whenever individual replacement is indicated. In this connection, the individual cartridges have end caps which are in the shape of truncated cones, with matching or mating truncated conical openings being formed in the end caps or end plates of the chamber assembly. Additionally, the truncated ports formed in the end plates have an inwardly extending flange or lip to function as a stop and hold the cartridges securely in place sealed within the conical openings, thereby facilitating ease of removal and/or installation. Additionally, O-rings may be utilized, with the O-rings being retained or held in annular grooves formed in the end caps along with the inwardly extending annular lip. In any event, given the tolerances in manufacture, and given that the length of the assembly will be indexed off of that certain cartridge having the greatest axial length, the mating truncated cone arrangement provides for reliable sealing of all cartridges in the overall arrangement. The O-ring arrangement likewise provides for reliable seals.
The features of the present invention provide for ease of system design as contrasted with conventional usage of either a jungle maze of connections tied to individual small diameter modules or, large diameter bundles, with concommitant risks of system failure due to partial membrane bundle leakage and the like, and also limited flexibility to mix fiber types, fluid types or pressures in one module assembly. The features of the present invention facilitate and expedite the steps involved in system design. By way of example, systems may be designed to utilize columns of various diameters so as to provide for and facilitate the utilization of multiple numbers of cartridges including, for example, four, eight, twelve, and/or eighteen, and the like. The modules in which these cartridges are retained are preferably arranged in parallel configuration for proceeding with their processing applications. Larger numbers of cartridges may be utilized as well.
Therefore, it is a primary object of the present invention to provide an improved modular assembly for cartridges with groups or bundles of hollow fibers, and wherein the modular assembly provides means for operatively retaining a plurality of such cartridges in place within the confines of a reaction or reactivity zone.
It is a further object of the present invention to provide an improved modular assembly for mounting a plurality of hollow fiber cartridges, with the interior of the modular assembly defining a reactivity zone or chamber which accommodates the flow of a sweep gas or liquid, vacuum, reactive fluid, or the like.
Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification and accompanying drawings.
REFERENCES:
patent: 3698559 (1972-10-01), Manjikian
patent: 4806246 (1989-02-01), Nomura
patent: 4824444 (1989-04-01), Nomura
pate
Applied Membrane Technology, Inc.
Haugen Law Firm PLLP
Menon Krishnan S
Walker W. L.
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