Cleaning of membrane surfaces

• US 3,912,624 A
• Filed: 03/26/1974
• Issued: 10/14/1975
• Est. Priority Date: 03/26/1974
• Status: Expired due to Term

• Current Assignee: James L. Jennings
• Original Assignee: James L. Jennings
• Inventors: Jennings, James L.
• Primary Examiner(s): Spear, Jr., Frank A.
• Application Number:
  US05/454,883
• Time in Patent Office: 567 Days
• Field of Search: 210/355,353,433,321,23,81,82,409,410,411
• US Class Current: 210/636
• CPC Class Codes: B01D 2321/06 Use of osmotic pressure, e.g. direct osmosis
• CPC Class Codes: B01D 2321/08 Use of hot water or water vapor
• CPC Class Codes: B01D 2321/16 Use of chemical agents
• CPC Class Codes: B01D 2321/167 Use of scale inhibitors
• CPC Class Codes: B01D 65/02 Membrane cleaning or sterilisation ; Membrane regeneration

Abstract

In effecting the periodic cleaning of ultrafiltration and reverse osmosis type membrane separation units, the procedure is improved and shortened by utilizing a plurality of purgings, or flushings, that cause water droplets to be blown along in a high speed air stream such that there is a resulting removal of accumulated solids from a membrane surface. During purging, air is used until substantially all the water droplets are blown off the membrane surfaces but is not continued until the membrane starts to dry out.

Claims

1. AN IMPROVED RAPID METHOD FOR CLEANING THE MEMBRANE SURFACES OF A PLURALITY OF MEMBRANE SEPARATION UNITS AFTER BEING IN USE, SAID UNITS HAVING FLUID PASSAGEWAYS THEREBETWEEN, WHICH METHOD COMPRISES THE STEPS OF:

PARTIALLY FILLING SAID FLUID PASSAGEWAYS, WITH WATER, PERIODICALLY PURGING SAID PASSAGEWAYS WITH A CONTINUOUS AIR STREAM AT SUPERATMOSPHERIC PRESSURE TO CAUSE A NON-PLUG FLOW OF WATER DROPLETS TO MOVE AT HIGH SPEED OVER THE MEMBRANES OF SAID SEPARATION UNITS TO THEREBY REMOVE ACCUMULATED MATERIALS, PRIOR TO EACH STEP OF PARTIALLY FILLING OF SAID PASSAGEWAYS WITH WATER CONDUCTION AN OSMOTIC BACK-FLUSHING THROUGH SAID MEMBRANE SURFACES WHEREBY TO EFFECTUATE AN INITIAL DISLODGING OF MATERIALS FROM SAID MEMBRANE SURFACES, AND INTERMITTENTLY REPEATING SAID PURGING STEP TO THEREBY EFFECT SUBSTANTIAL REMOVAL OF ALL ACCUMULATED MATERIALS AND ALL WATER DROPLETS FROM SAID MEMBRANE SURFACES WITHOUT PERMITTING DRYING OF SAID MEMBRANES DURING ANY STAGE.

2. The method of claim 1 further characterized in that the fluid passageways are initially partially filled with water containing a cleaning component.

3. The method of claim 1 further characterized in that the fluid passageways are initially partially filled with water containing a sanitizing fluid for the prevention of bacteriological growths.

4. The method of claim 1 further characterized in that the air stream is at a pressure of at least about 20 psi.

5. The method of claim 1 further characterized in that during the repeating of the purging with an air stream there is a reversal of the direction of air flow for at least one of the purges.