Automatic flushing system for membrane separation machines such as reverse osmosis machines

• US 3,992,301 A
• Filed: 03/05/1975
• Issued: 11/16/1976
• Est. Priority Date: 11/19/1973
• Status: Expired due to Term

• Current Assignee: Chase Manhattan Mortgage Corporation (JP Morgan Chase & Co)
• Original Assignee: Raypak, Inc. (Paloma Co., Ltd.)
• Inventors: Martin, Fred E., Shippey, Frank R., Vance, Timothy C.
• Primary Examiner(s): Spear, Jr., Frank A.
• Application Number:
  US05/555,640
• Time in Patent Office: 622 Days
• Field of Search: 210/321, 210/409, 210/23, 210/433, 210/140, 210/96 M
• US Class Current: 210/636
• CPC Class Codes: B01D 2313/48 Mechanisms for switching between regular separation operations and washing
• CPC Class Codes: B01D 2321/02 Forward flushing
• CPC Class Codes: B01D 2321/06 Use of osmotic pressure, e.g. direct osmosis
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 61/30 Accessories; Auxiliary operation
• CPC Class Codes: B01D 61/32 Controlling or regulating
• CPC Class Codes: B01D 61/52 Accessories; Auxiliary operation
• CPC Class Codes: B01D 61/54 Controlling or regulating
• CPC Class Codes: B01D 65/02 Membrane cleaning or sterilisation ; Membrane regeneration

Abstract

An automatic flushing and cleaning system for membrane separation machines such as reverse osmosis machines having plural modules or membranes. Cleaning may be by way of reducing the pressure to allow the membrane to relax, by the injection of air or inert gas to provide turbulence, and/or by injection of flushing liquid which may include chemical cleaning additives. Pumps, automatic valving, and pressure controls are provided, along with a complete timer operated electrical sequencing system whereby desired purging, flushing and cleaning cycles are automatically undertaken at periodic intervals or in response to one or more preferred conditions.

Claims

1. In an apparatus of a type providing at least one module comprising a core member having a semi-permeable membrane on the surface thereof, in a position to be exposed to a feed liquid in a manner whereby the liquid can permeate through the membrane producing flows of permeate and concentrate, means for directing a feed liquid from a source thereof to said membrane under pressure, a source of flush liquid separate from said feed liquid and a source of air for cleaning purposes, control means for causing interruption of circulation of feed liquid through the apparatus and for initiating a cleaning cycle, the control means including means for releasing the pressure in the module and for causing flow therethrough of said flush liquid for cleaning, the control means haing means to initiate the flow of flushing liquid and for injection of air from said source under pressure in the flushing liquid for a timed interval whereby the air expands in the liquid creating turbulence, serving to clean the surface of the membrane.

2. An apparatus as in claim 1 including a source of chemical additive, the control means including means to initiate a flow of chemical additive with the flushing liquid and the air.

3. Apparatus as in claim 2, including means for terminating the flow of chemical additive while continuing the flow of the flushing liquid for purging prior to restarting the flow of feed liquid.

4. An apparatus as in claim 1 wherein the control means includes electrical valves for controlling flows of feed liquid, flushing liquid and air, the control means including electrical sequencing means for operating the valves to discontinue feed liquid flow, to open a discharge line from the module and to initiate the flows of flush liquid and air.

5. An apparatus as in claim 4, wherein said sequencing means includes electrical contacts for shunting the relatively low pressure contacts, whereby to maintain operation of the system, when the pressure in the module has been dropped for cleaning purposes.

6. An apparatus as in claim 1, including pressure responsive electrical means responsive to pressure in the module, said means including switch contacts responsive to pre-determined relatively high and relatively low pressures and means to bypass the relatively low pressure contacts during start up of normal operation of the system after cleaning.

7. An apparatus as in claim 1, including a back pressure regulating valve in the outlet line of the module, valve means connected in bypassing relationship with said back pressure regulating valve and means for opening said valve in bypassing relationship for reducing the pressure in the module.

8. An apparatus as in claim 1, wherein said means for circulating the feed liquid through the apparatus includes a pump, said source of flush liquid being connected whereby the pump can pump the flush liquid through the module.

9. An apparatus as in claim 1, including condition responsive means responsive to a condition indicative of a need for cleaning of the module for initiating the cleaning cycle.

10. An apparatus as in claim 1, including a branch conduit connected between the inlet to the module and a discharge line through a controllable valve.

11. A method of cleaning an apparatus of the type having a module which includes a core member having a semipermeable membrane on the surface thereof and means to direct feed liquid under pressure to said membrane whereby the liquid can permeate through the membrane producing flows of permeate and concentrate, the steps of stopping the flow of feed liquid through the module, releasing the pressure in said module initiating a flow of flushing liquid other than said feed liquid through the module, and injecting gas under pressure into the flushing liquid whereby the gas expands in the liquid creating turbulence serving to clean the surface of the membrane in the module.

12. A method as in claim 11, including the step of injecting chemical additive into the flushing liquid going into the module.

13. A method as in claim 12, including the step of discontinuing the flow of chemical additive while continuing the flow of flushing liquid for purging purposes.