Impressed current cathodic protection system

• US 5,476,576 A
• Filed: 04/14/1994
• Issued: 12/19/1995
• Est. Priority Date: 08/15/1991
• Status: Expired due to Fees

• Current Assignee: Solomon Corrosion Consulting Services Pty Limited, WINN and Coales International Limited
• Original Assignee: Solomon Corrosion Consulting Services Pty Limited, WINN and Coales International Limited
• Inventors: Solomon, Isaac, Phang, Bob
• Primary Examiner(s): TUNG, TA HSUNG
• Application Number:
  US08/193,195
• Time in Patent Office: 614 Days
• Field of Search: 204/130, 204/147, 204/148, 204/196, 204/197
• US Class Current: 205/734
• CPC Class Codes: C23F 13/06 Constructional parts, or assemblies of cathodic-protection apparatus
• CPC Class Codes: E02D 31/06 against corrosion by soil or water

Abstract

A system for impressed current cathodic protection of a structure having a corrodible metal reinforcing member comprising: a) an electron source having a positive terminal and a negative terminal connected to said corrodible metal reinforcing member such that electrons can flow from said negative terminal to said reinforcing member; b) an anode proximate said structure connected to said positive terminal of said electron source; and c) a pliable conductive substrate substantially enveloping said anode and in intimate contact with at least a portion of said structure. The pliable conductive substrate used comprises a suspension of a conductive compound in a viscous liquid impregnated in a flexible support medium.

Claims

1. A system for impressed current cathodic protection of a structure having a corrodible metal reinforcing member comprising:

(a) an electron source having a positive terminal and a negative terminal connected to said corrodible metal reinforcing member such that electrons can flow from said negative terminal to said reinforcing member;

(b) an anode proximate said structure and connected to said positive terminal of said electron source; and

(c) a pliable conductive substrate substantially enveloping said anode and in intimate contact with at least a portion of said structure wherein said pliable conductive substrate comprises a pliable conductive medium comprising a conductive material in a viscous liquid and wherein said viscous liquid is a grease.

2. A system according to claim 1, wherein said pliable conductive substrate comprises a flexible support medium impregnated with said pliable conductive medium.

3. A system according to claim 2, wherein said flexible support medium is in the form of a tape.

4. A system according to claim 2, wherein said anode is in the form of a mesh juxtaposed between two layers of said pliable conductive substrate.

5. A system according to claim 2, wherein said anode substantially surrounds at least a portion of said structure.

6. A system according to claim 1, wherein said pliable conductive substrate is in the form of a putty.

7. A system according to claim 6, wherein said anode is in the form of a wire embedded in said substrate.

8. A system according to claim 6, wherein said anode is in positioned in a recess provided in said structure.

9. A system according to claim 1, wherein said conductive material is graphite in the form of powder and/or flakes.

10. A system according to claim 1, wherein said pliable conductive substrate has a resistivity of less than 500 ohm.cm.

11. A system according to claim 1, wherein said pliable conductive substrate has a resistivity of between 50 and 200 ohm.cm.

12. A method of providing impressed current cathodic protecting to a structure having a corrodible metal reinforcing member comprising the steps of:

(a) connecting said corrodible metal reinforcing member to a negative side of an electron source;

(b) forming a recess in said structure;

(c) positioning an anode in said recess, said anode being surrounded by a pliable conductive substrate in intimate contact with said structure wherein said conductive substrate comprises a pliable conductive medium comprising a conductive material in a viscous liquid and wherein said viscous liquid is a grease; and

(d) connecting said anode to a positive side of said electron source.

13. A method according to claim 12, wherein said recess is filled substantially flush to a surface of the structure after said anode and pliable conductive substrate have been positioned therein.

14. A method of providing impressed current cathodic protecting to a structure having a corrodible metal reinforcing member comprising the steps of:

(a) connecting said corrodible metal reinforcing member to a negative terminal of an electron source;

(b) applying a flexible support medium impregnated with a pliable conductive medium to at least a portion of said structure wherein said conductive medium comprises a conductive material in a viscous liquid and wherein said viscous liquid is a grease;

(c) at least partially embedding an anode in said pliable conductive medium; and

(d) connecting said anode to a positive terminal of said electron source.

15. A method according to claim 14, wherein said anode is substantially covered by a further layer of a flexible support medium impregnated with a pliable conductive medium.

16. A method according to claim 14, wherein said flexible support medium and pliable conductive medium are overwrapped by a mechanical protection means.

17. A pliable conductive substrate for used in an impressed current cathodic protection system which comprises a flexible support medium impregnated with a suspension of a conductive material in a viscous liquid and wherein said viscous liquid is a grease.

18. A pliable conductive substrate according to claim 17, wherein said flexible support medium is a woven or non-woven porous tape.

19. A pliable conductive substrate according to claim 17, wherein said conducive material is graphite.