Technotoy Stage 1


All the pictures in these web pages are made by Roger Alexander

They all have priority dates and so are the intellectual property of Cathodic Protection Network.



This is the basis of measurements in cathodic protection. This is the historical codification of the laws of nature governing electrochemistry



This is how it is recommended in the laboratory.



This is an explanation that is often ignored.



This is how one of the measurements is often carried out in the laboratory



This is a ground contact electrode that is wrongly termed a 'half-cell'.



This is the measuring circuit thats is practiced in field work.



This is Jose making Close Interval Potential Survey (CIPS) measurements at the Cathodic Protection Network training centre at Guararema, SP Brazil.



This is the training centre under construction



This is the training centre under construction



This is an example of a field report sheet in which readings were entered before being submitted to an office where they were entered into a main frame computer.



This is a photo of a system that I set up in Nigeria before computers were available. I used map pins connected with cotton thread as a moving graph that was adjusted by the survey technicians returning from their manual field acquisition. Thie enabled all staff to visualise the electrical equilibrium between the pipeline metal and the ground over the whole of our network.



This is Bomu Manifold where I devised DCVG as a method of mapping ground potentials.



This is how NACE teaches what they call the 'IR drop in the soil'.



This is the real scientific IR drop.



This shows what is really going on.



This shows how Kirchhoff's laws of electricity manifest themselves in field cathodic protection work.



You can see how resistances in parallel effect the sprad of protective currents in a simlar way to the inverse square law of radiation.



This results in the potential of the ground itself having a gradient. This is not a voltage gradient as there can be no reference potential due to Gibbs Free Energy.



You can visualise this effect in the above drawing but must realize that at ground surface this is hemi-spherical whereas in deep anodes the effect is spherical.



On the metallic side of the meter we must use the very low and measurable resistance of the conductive paths to calculate the exact potential of the metal at each coating fault/interface with the electrolyte.



These are display pieces necessary to explain the basics to people who have been taught wrongly.



This is a physical model of a groundbed using electronic components.



This is the underside of the electronic model of a cathodic protection equivalent circuit.



This gives us the base line for our graphs and datum for our calculations as it is a definitive crterion that shows exactly when corrosion has stopped and the status at which equilibrium is reached without corrosion current flowing.



This shows the exact status when the cathodic protection is not in effect.



This shows the exact ststus when the cathodic protection sstem is effective at this location.



This is pure copper in a saturated solution of copper sulphate with a tooth pick through the bottom to provide a passive connection with the other parts of the measuring circuit. This is what others might incorrectly call a 'half-cell'.



This is the set up