Wear indicator for sacrificial anode

• US 6,932,891 B2
• Filed: 05/04/2004
• Issued: 08/23/2005
• Est. Priority Date: 05/06/2003
• Status: Active Grant

• Current Assignee: SciCast International, Inc.
• Original Assignee: Performance Metals, Inc. (Consolidated Stainless, Inc.)
• Inventors: Elder, James, Wigg, Martin, Leipert, Henry, Dixon, Kelvin P.
• Primary Examiner(s): Bell, Bruce F.
• Application Number:
  US10/838,696
• Publication Number:
  US 20040222084A1
• Time in Patent Office: 476 Days
• Field of Search: 204/196.06, 204/196.02, 204/196.21, 204/196.36, 204/196.37, 204/404, 204/280, 324/71.1, 324/71.2, 73/86, 340/572.1, 342/42, 342/44, 342/51, 343/872, 343/873
• US Class Current: 204/196.06
• CPC Class Codes: C23F 13/22 Monitoring arrangements therefor

Abstract

An apparatus for indicating when a predetermined portion of a sacrificial anode has been corroded comprises a detector embedded within the interior of the sacrificial anode initially at a predetermined distance from an exposed exterior surface of the sacrificial anode. The detector detects the absence of sacrificial anode material when the predetermined portion has corroded and generates a detection signal. A monitoring system communicates with the detector for receiving detection signals and generates an indicator signal when a detection signal is received. An indicator in communication with the monitoring system receives indicator signals and generates an alarm when an indicator signal is received.

Claims

1. An apparatus for visually indicating when a predetermined portion of a sacrificial anode has been corroded, the apparatus comprising a first non-corroding wear indicator embedded within the interior of the sacrificial anode at at least a first predetermined distance from an exposed exterior surface of the sacrificial anode so that the wear indicator is not visible when the sacrificial anode is initially installed on a metal to be protected, the wear indicator becoming exposed and visible only after at least the predetermined portion of the sacrificial anode has corroded.

2. The apparatus as recited in claim 1, wherein the sacrificial anode is generally semi-circular in cross section with an initial radius R1 and the wear indicator is located at a radius R2 where the difference between radius R1 and radius R2 is the predetermined distance.

3. The apparatus as recited in claim 2, wherein the radius R2 is approximately one-half of the radius R1.

4. The apparatus as recited in claim 1, wherein the wear indicator is made of a polymeric material.

5. The apparatus as recited in claim 1, wherein the wear indicator is a bright, easily visible color.

6. The apparatus as recited in claim 1, wherein the wear indicator is generally cylindrical so that when the predetermined portion of the sacrificial anode has corroded an axial end surface of the wear indicator is exposed and visible as a generally circular spot.

7. The apparatus as recited in claim 1, wherein the wear indicator comprises a button which is biased to pop up beyond the surface of the sacrificial anode when the predetermined portion of the sacrificial anode has corroded.

8. The apparatus as recited in claim 7, wherein the button is brightly colored and highly visible when popped up.

9. The apparatus as recited in claim 1, further including a second non-corroding wear indicator embedded within the interior of the sacrificial anode at a second predetermined distance from the exposed exterior surface of the sacrificial anode, the second predetermined distance being less than the first predetermined distance so that the second wear indicator becomes exposed and visible after the sacrificial anode has corroded to the extent of the second predetermined distance.

10. The apparatus as recited in claim 9, wherein the first and second wear indicators are different colors.

11. An apparatus for indicating when a predetermined portion of a sacrificial anode has been corroded, the apparatus comprising:

a detector embedded within the interior of the sacrificial anode initially at a predetermined distance from an exposed exterior surface of the sacrificial anode, the detector for detecting the absence of sacrificial anode material when the predetermined portion has corroded and for generating a detection signal;

a monitoring system in communication with the detector for receiving detection signals and for generating an indicator signal when a detection signal is received; and

an indicator in communication with the monitoring system for receiving indicator signals and for generating an alarm when an indicator signal is received.

12. The apparatus as recited in claim 11, further including a housing embedded within the sacrificial anode for containing the detector, the monitoring system and the indicator.

13. The apparatus as recited in claim 11, wherein the detector comprises a pair of spaced electrical contacts which are initially not electrically connected to each other, the corrosion of the predetermined portion of the sacrificial anode resulting in both contacts being exposed to an electrolyte to electrically connect the contacts and generate a detection signal.

14. The apparatus as recited in claim 11, wherein the detector comprises a pair of spaced electrical contacts which both initially engage the sacrificial anode so that the contacts are initially electrically connected to each other, the corrosion of the predetermined portion of the sacrificial anode resulting in the electrical connection between the contacts being broken to generate a detection signal.

15. The apparatus as recited in claim 11, wherein the alarm is an audible alarm.

16. The apparatus as recited in claim 11, wherein the alarm is a visible alarm.

17. The apparatus as recited in claim 13, wherein the electrical contacts are initially both at the same distance from the exposed surface of the sacrificial anode.

18. The apparatus as recited in claim 17, further including a third electrical contact embedded within the sacrificial anode at a distance which is different from the predetermined distance.

19. An apparatus for indicating when a predetermined portion of a sacrificial anode has been corroded, the apparatus comprising a radio frequency identification (RFID) device embedded within the interior of the sacrificial anode at a predetermined distance from an exposed exterior surface of the sacrificial anode, the presence of the RFID device being detectable by a detection system until the predetermined portion of the sacrificial anode has corroded, whereupon the RFID device separates from the sacrificial anode and is no longer detectable.