Cross flow microfilter

• US 4,797,211 A
• Filed: 12/24/1986
• Issued: 01/10/1989
• Est. Priority Date: 12/24/1985
• Status: Expired due to Fees

• Current Assignee: Kernforschungszentrum Karlsruhe GmbH
• Original Assignee: Kernforschungszentrum Karlsruhe GmbH
• Inventors: Ehrfeld, Wolfgang, Munchmeyer, Dietrich
• Primary Examiner(s): SPEAR JR, FRANK
• Application Number:
  US06/945,882
• Time in Patent Office: 748 Days
• Field of Search: 264/22, 210/498, 210/456, 210/636, 210/500.25, 210/500.26, 210/321.84
• US Class Current: 210/321.84
• CPC Class Codes: B01D 2315/10 Cross-flow filtration
• CPC Class Codes: B01D 2325/021 Pore shapes
• CPC Class Codes: B01D 61/18 Apparatus therefor
• CPC Class Codes: B01D 67/0062 by micromachining techniques, e.g. using masking and etching steps, photolithography
• CPC Class Codes: B01D 67/0069 by deposition from the liquid phase, e.g. electrochemical deposition B01D67/0046 takes precedence
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 71/02 Inorganic material
• CPC Class Codes: B01D 71/05 Cermet materials
• CPC Class Codes: B01J 2219/00909 using filters

Abstract

A cross flow microfilter comprises a filter housing having a flow chamber wherein a fluid is introduced on one side and a concentrate is removed on the opposite side a collection chamber from which a filtrate is removed, and at least one microporous membrane over whose one surface the fluid to be filtered flows in a parallel stream and whose other surface is oriented toward the collection chamber, the membrane having pores of a width between about 0.1 micron and 30 micron, the improvement wherein the pores of the membrane have slit-shaped cross-sections and given profiles, and are formed by a plurality of webs arranged in rows with predetermined spacing and by terminating plates which cover the webs, and the webs are applied onto one of the two plates by X-ray lithographic means, X-ray depth lithographic-galvanoplastic means, or molding and galvanoplastic means.

Claims

1. In a cross flow microfilter comprising a filter housing having a flow chamber wherein a fluid is introduced through at least one inlet and a concentrate is removed through at least one outlet on the side opposite the inlet, a collection chamber from which a filtrate is removed, and at least one microporous membrane disposed between the flow chamber and the collection chamber, said membrane having an inlet surface along which the fluid to be filtered flows, an outlet surface oriented toward the collection chamber and pores of a width between about 0.1 micron and 30 microns, the improvement wherein

said membrane comprises a plurality of webs disposed in at least one row and spaced at a predetermined distance from one another to define openings having slit-shaped cross-sections said openings having uniform and predetermined widths and given profiles and constituting said pores;

said microfilter further comprises two terminating plates enclosing said webs and laterally bounding said openings; and

said webs are formed on one of said plates by one of X-ray lithography, X-ray depth lithographic-galvanoplasty molding, and molding with subsequent galvanoplasty.

2. The cross flow microfilter of claim 1, wherein the webs are arranged in the flow chamber so that the direction of flow through the pores is at an angle of between about 90°

to 135°

with respect to the direction of flow of the fluid along the inlet surface.

3. The cross flow microfilter of claim 1, wherein the side of each web adjacent the flow chamber is rounded.

4. The cross flow microfilter of claim 1, wherein the webs have a height between the plates between about 0.1 mm and 2 mm.

5. The cross flow microfilter of claim 1, wherein

said webs are arranged in a plurality of pairs of rows between the two plates;

and

within every pair of web rows, the web rows are oriented as a mirror image to one another in such a manner that they enclose therebetween a respective one of said chambers.

6. The cross flow microfilter of claim 5, wherein said flow chamber has a plurality of inlets and a plurality of outlets, and further comprising

an intake distributor and a concentrate collector, each having a plurality of branching points including end branches, each end branch of said intake distributor being connected to a respective inlet of the flow chamber and each end branch of said concentrate collector being connected to a respective outlet of the flow chamber;

and wherein

said intake distsributor and said concentrate collector each further has two plates, and a plurality of partition walls, said partition walls having given profiles and being disposed at given positions between said walls.

7. The cross flow microfilter of claim 6, wherein each said plate of said distributor and of said collector is integral with a respective terminating plate of said microfilter, said partitions are formed on said plate of said distributor and said plate of said collector which are integral with said one terminating plate, and said partitions are covered by the other said plate of said distributor and said collector.