# US 5,344,565 A · Method of treating a clogged porous medium

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- Number: US 5,344,565 A
- Document ID: US5344565A
- Status: Granted
- Kind: A
- Application number: 08/097,450
- Filed: 1993-07-26
- Granted: 1994-09-06
- Earliest claimed: 1993-07-26
- Assignees: Pall Corporation
- Inventors: Peter J. Degen; Tony Alex; Michael R. Gildersleeve
- Web page: https://patentgrep.com/patent/US5344565A

## CPC

- B01D 65/02: Membrane cleaning or sterilisation {; Membrane regeneration}
- A23C 9/1422: {by ultrafiltration, microfiltration or diafiltration of milk, e.g. for separating protein and lactose; Treatment of the UF permeate}
- B01D 41/04: of rigid self-supporting filtering material
- C12H 1/063: {Separation by filtration}
- B01D 2321/162: Use of acids
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- A23C: DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; PREPARATION THEREOF (preservation thereof A23B11/00)
- C12H: PASTEURISATION, STERILISATION, PRESERVATION, PURIFICATION, CLARIFICATION OR AGEING OF ALCOHOLIC BEVERAGES; METHODS FOR ALTERING THE ALCOHOL CONTENT OF FERMENTED SOLUTIONS OR ALCOHOLIC BEVERAGES (simulation ageing by flavouring C12G3/06)

## Abstract

The present invention provides a method of treating a clogged porous medium comprising contacting a porous medium clogged in the course of filtering a protein-containing fluid, such as milk, beer, or wine, with an aqueous citrate solution.

## Claims

### Claim 1

A method of treating a clogged porous medium comprising contacting a porous medium clogged in the course of filtering a protein-containing fluid with an aqueous citrate solution.

### Claim 2 (depends on 1)

The method of claim 1, wherein said protein-containing fluid is a natural protein-containing fluid.

### Claim 3 (depends on 2)

The method of claim 2, wherein said protein-containing fluid is selected from the group consisting of milk, beer, and wine.

### Claim 4 (depends on 3)

The method of claim 3, wherein said protein-containing fluid is milk.

### Claim 5 (depends on 1)

The method of claim 1, wherein said porous medium is a microporous membrane.

### Claim 6 (depends on 5)

The method of claim 5, wherein said microporous membrane is a polyamide membrane.

### Claim 7 (depends on 1)

The method of claim 1, wherein said aqueous citrate solution comprises no more than about 0.5 wt. % citrate ion.

### Claim 8 (depends on 7)

The method of claim 7, wherein said aqueous citrate solution is an aqueous solution of a citrate salt selected from the group consisting of potassium and sodium citrate salts and combinations thereof.

### Claim 9 (depends on 8)

The method of claim 8, wherein said aqueous citrate solution is an aqueous solution of trisodium citrate.

### Claim 10 (depends on 7)

The method of claim 7, wherein said protein-containing fluid is selected from the group consisting of milk, beer, and wine.

### Claim 11 (depends on 10)

The method of claim 10, wherein said protein-containing fluid is milk.

### Claim 12 (depends on 11)

The method of claim 11, wherein said porous medium is a microporous membrane.

### Claim 13 (depends on 12)

The method of claim 12, wherein said aqueous citrate solution is an aqueous solution of trisodium citrate.

### Claim 14 (depends on 1)

The method of claim 1, wherein said aqueous citrate solution is at ambient temperature.

### Claim 15 (depends on 1)

The method of claim 1, wherein said aqueous citrate solution is at about 25.degree. C. to about 80.degree. C.

### Claim 16 (depends on 1)

The method of claim 1, wherein said porous medium is contacted with said aqueous citrate solution at no more than about 30 psi.

### Claim 17 (depends on 1)

The method of claim 1, wherein said porous medium is contacted with said aqueous citrate solution at about 5 psi to about 20 psi.

### Claim 18 (depends on 1)

The method of claim 1, wherein said porous medium is contacted with said aqueous citrate solution for no more than about one hour.

### Claim 19 (depends on 18)

The method of claim 18, wherein said porous medium is contacted with said aqueous citrate solution for no more than about 30 minutes.

### Claim 20 (depends on 19)

The method of claim 19, wherein said porous medium is contacted with said aqueous citrate solution for no more than about 10 minutes.

### Claim 21 (depends on 1)

The method of claim 1, wherein said clogged porous medium is contacted with said aqueous citrate solution such that said clogged porous medium achieves at least a 50% recovery of its initial water filtration flux prior to filtration with said protein-containing fluid.

### Claim 22 (depends on 21)

The method of claim 21, wherein said clogged porous medium is contacted with said aqueous citrate solution such that said clogged porous medium achieves at least a 80% recovery of its initial water filtration flux prior to filtration with said protein-containing fluid.

### Claim 23 (depends on 22)

The method of claim 22, wherein said clogged porous medium is contacted with said aqueous citrate solution such that said clogged porous medium achieves at least a 90% recovery of its initial water filtration flux prior to filtration with said protein-containing fluid.

### Claim 24 (depends on 21)

The method of claim 21, wherein said protein-containing fluid is a natural protein-containing fluid.

### Claim 25 (depends on 24)

The method of claim 24, wherein said protein-containing fluid is selected from the group consisting of milk, beer, and wine.

### Claim 26 (depends on 25)

The method of claim 25, wherein said protein-containing fluid is milk.

### Claim 27 (depends on 21)

The method of claim 21, wherein said porous medium is a microporous membrane.

### Claim 28 (depends on 21)

The method of claim 21, wherein said aqueous citrate solution comprises no more than about 1 wt. % citrate ion.

### Claim 29 (depends on 28)

The method of claim 28, wherein said aqueous citrate solution is an aqueous solution of a citrate salt selected from the group consisting of potassium and sodium citrate salts and combinations thereof.

### Claim 30 (depends on 29)

The method of claim 29, wherein said aqueous citrate solution is an aqueous solution of trisodium citrate.