Reference Potential in Cathodic Protection

And the Question is ??

or is this an add with no contact info ??

http://cr4.globalspec.com/search/sitesearch?do=show&us=8984&srchobjs=t,be,c

This is 'the engineers place for news and discussion'

The news is that a demonstration centre has opened in South Africa and I am a member of this forum and my real name is Roger Alexander.

The discussion is that the cathodic protection industry has been operating on a wrong assumption for at least 40 years and that is why it is clouded in mystery and long words.

In South Africa I have met many senior practicing cathodic protection engineers who do not believe in the advice they are given by many advisory bodies and have worried from the very beginning of their careers about the so called 'reference electrode' or half cell. In the early 1970's I was given a half-cell and a voltmeter and told to take pipe-to-soil 'potential' measurements. I was told that the half-cell was the reference to be compared to the pipe metal potential. I found straight away that the voltage depended on the position of the 'half-cell' which could not therefore be a 'reference' potential.

I soon found out that all cathodic protection calculations are based on this myth.

It is about time that the pipeline industry realised that all this business of the 'off potential' is just an attempt to justify using the half cell as a reference, and has no foundation in science as the true immediate off potential is only possible in laboratory conditions with specific pH values and conductivity.

DCVG (which I invented in 1974/5) relies on the fact that the half cell is NOT a reference electrode.

I am not advertising anything but engineering integrity.

I see

your original post did not explain what you have just expained

and for those like me who did not understand the first post, the links below may help

• The Alexander Cell - Cathodic Protection Network, cathodic ... In the picture above the Alexander Cell is placed on the electrolyte and connected to a micro-ammeter. The meter shows zero as the circuit is not complete. ...
  www.cathodic-protection-network.com/alce1.htm - Cached - Similar
• Inhibition of HBsAg secretion from Alexander cell line by ... by S Jayaram - 1996 - Cited by 20 - Related articles
  Alexander cell line, an human hepatocellular carcinoma derived cell line which has the property of secreting HBsAg in the supernatant was used to study the ...
  www.ncbi.nlm.nih.gov/pubmed/8972151

Thanks for your help, the second link is about a different Alexander in a different field of science.

My own Alexander Cell was named by Tim ffrench-Mullens, the founder of the Institute of Corrosion Science and technology in the UK. I had devised the system of electrodes in the late 1970's when I was in charge of corrosion control for Shell-BP Development Corporation, Nigeria. Extensive field experience before then had left me without doubt that the half-cell was not a reference potential as required to support the application of CP science.

Having developed DCVG to identify currents in the earth I further developed the more accurate ground potential mapping that is part of Cathodic Protection Network technology. Despite developing many techniques to extrapolate true data from the use of half-cells my research led me to the conclusion, confirmed by Professor Frank Walshe of Southampton University, that the only way to measure the effectiveness of cathodic protection is with an electrode system and not with a reference potential.

The Alexander Cell is a corrosion cell in which the current can be measured in closed circuit. The current results from the EMF of the corrosion reaction at the anode of a known corrosion cell and is not like a normal coupon that measures the potential close to both anode and cathode of a suspect corrosion cell.

The newly patented Alexander Cell makes it possible to take a potential measurement in the field with all the attributes of a laboratory experiment.

If ISO and other advisory bodies insist on basing their codes of practice on the use of a reference cell then it can only be applied with an arrangement similar to that used in laboratories.

Experience with the Alexander Cell over the past 30 years has shown that corrosion is stopped by cathodic protection where traditional readings have ranged from -0.550v to -1.25v and that interference currents in the earth are part of the measurement.

The Alexander Cell shows the exact equilibrium at which corrosion stops and can be used in conjuction with all other surveys to balance the cathodic protection systems of networks of pipelines.

The present difficulties in AC mitigation and measuring the effects of overhead power lines are largely due to the misunderstanding of the use of the ground contact electrode (the half-cell).