Continuously Variable Aeration

• US 20080156745A1
• Filed: 09/15/2005
• Published: 07/03/2008
• Est. Priority Date: 09/15/2004
• Status: Active Grant

• Current Assignee: Evoqua Water Technologies LLC
• Original Assignee: US Filter Wastewater Group Incorporated (Siemens AG)
• Inventors: Brois, Etienne Ulysse, Johnson, Warren Thomas, Zha, Fufang, Phelps, Roger William, Beck, Thomas William
• Granted Patent: US 8,377,305 B2
• Time in Patent Office: Days
• US Class Current: 210/791
• CPC Class Codes: B01D 2313/18 Specific valves
• CPC Class Codes: B01D 2313/26 Specific gas distributors or gas intakes
• CPC Class Codes: B01D 2315/06 Submerged-type; Immersion type
• CPC Class Codes: B01D 2321/04 Backflushing
• CPC Class Codes: B01D 2321/185 Aeration
• CPC Class Codes: B01D 2321/2066 Pulsated flow
• CPC Class Codes: B01D 61/20 Accessories; Auxiliary operations
• CPC Class Codes: B01D 61/22 Controlling or regulating
• CPC Class Codes: B01D 63/024 with a single potted end
• CPC Class Codes: B01D 63/046 in separate housings
• CPC Class Codes: B01D 65/08 Prevention of membrane fouling or of concentration polarisation
• CPC Class Codes: C02F 1/444 by ultrafiltration or microfiltration

Abstract

A method of controlling fouling in a membrane filtration system (5) of the type where gas is used to clean or scour the membranes (6) wherein the method includes supplying the gas to the system with a continuously variable flow rate. A continuously variable valve arrangement (17) is also disclosed.

Claims

1. A method of controlling fouling in a membrane filtration system having at least one membrane, comprising the steps of:

supplying a gas to the system, wherein said gas is supplied with a continuously variable flow rate; and

scouring said at least one membrane with said gas.

2. A method according to claim 1 wherein the system includes a number of modules and the supply of gas to each module has a continuously variable flow rate.

3. A method according to claim 1 wherein the continuously variable gas flow rate ranges from a high flow to a low flow.

4. A method according to claim 3 wherein the low flow is zero.

5. A method according to claim 1 wherein the flow rate pattern of the gas flow follows a continuously variable curve in the form of a sinusoid.

6. A method according to claim 1 wherein the flow rate pattern of the gas flow follows a continuously variable curve in the form a triangular wave.

7. A membrane filtration system including comprising:

one or more membranes for removing undesirable substances; and

a source of gas for providing a gas flow to form bubbles which scour the surfaces of the membrane, wherein said source of gas provides said gas flow at a continuously variable flow rate.

8. A membrane filtration system according to claim 7 wherein the rate of flow of gas from said gas source is continuously variable.

9. A membrane filtration system according to claim 8 wherein said gas source is a variable speed blower.

10. A membrane filtration system according to claim 7 wherein said gas source is coupled to the filtration system via a flow control device and the flow control device varies the flow rate continuously.

11. A membrane filtration system according to claim 10 wherein said membrane filtration system includes a plurality of membrane modules and said flow control device has separate outlet ports connected to associated modules such that as the flow rate is being increased to one module or modules it is being reduced to another module or modules.

12. A membrane filtration system according to claim 10 wherein said membrane filtration system includes a number of sets of modules and the gas flow to each set of modules has a continuously variable flow rate.

13. A membrane filtration system according to claim 12 wherein the membrane filtration system includes a number of feed containing vessels with each feed containing vessel having a respective set of modules located therein.

14. A membrane filtration system according to claim 10 wherein said flow control device includes a housing having an inlet port and one or more outlet ports, and a movable valve member for providing a continuously variable flow from said inlet port to said one or more outlet ports.

15. A membrane filtration system according to claim 14 wherein said movable valve member is a rotating distributor positioned within said housing to control flow from said inlet port to said one or more outlet ports.

16. A membrane filtration system according to claim 15 wherein said outlets ports are located relative to the rotating distributor such that one of said outlet ports is fully open when another is fully closed.

17. A membrane filtration system according to claim 14 wherein said movable valve member is a reciprocating distributor positioned within said housing to control flow from said inlet port to said one or more outlet ports.

18. A membrane filtration system according to claim 17 wherein said outlets ports are located relative to the reciprocating distributor such that one of said outlet ports is fully open when another of said outlet ports is fully closed.

19. A membrane filtration system according to claim 17 wherein said reciprocating distributor includes a piston slidably mounted in said housing, said housing being tubular and said outlet ports being located at either end thereof and said inlet port being located in a wall of said housing intermediate of the ends thereof.

20. A membrane filtration system according to claim 19 wherein said piston is arranged such that, as the piston moves between its limits, flow from the inlet port to one of said outlet ports is increased and the flow to another of said outlet ports is reduced.

21. A membrane filtration system according claim 14 wherein the movable valve member is continuously driven by a motor.

22. A membrane filtration system according claim 14 wherein said housing has a plurality of inlet ports.

23. A flow control device for use in the control of the flow of aerating gas in a membrane filtration system, comprising:

a housing having an inlet port and one or more outlet ports; and

a movable valve member for providing a continuously variable flow from said inlet port to said one or more outlet ports.

24. A flow control device according to claim 23 wherein said movable valve member is a rotating distributor positioned within said housing to control flow from said inlet port to said one or more outlet ports.

25. A flow control device according to claim 24 wherein said outlets ports are located relative to the rotating distributor such that one of said outlet ports is fully open when another is fully closed.

26. A flow control device according to claim 23 wherein said movable valve member is a reciprocating distributor positioned within said housing to control flow from said inlet port to said one or more outlet ports.

27. A flow control device according to claim 26 wherein said outlets ports are located relative to the reciprocating distributor such that one of said outlet ports is fully open when another of said outlet ports is fully closed.

28. A flow control device according to claim 26 wherein said reciprocating distributor includes a piston slidably mounted in said housing, said housing being tubular and said outlet ports being located at either end thereof and said inlet port being located in a wall of said housing intermediate of the ends thereof.

29. A flow control device according to claim 28 wherein said piston is arranged such that, as the piston moves between its limits, flow from the inlet port to one of said outlet ports is increased and the flow to another of said outlet ports is reduced.

30. A flow control device according to claim 23 wherein the movable valve member is continuously driven by a motor.

31. A flow control device according to claim 23 wherein said housing has a plurality of inlet ports.