The proposed STOPCOR method uses a combination of the aforementioned methods, thereby providing cathodic protection through impress current by the sacrificial anode in the self-contained device.
The impress current covers and protects wide metal surfaces with much less sacrificed mass of active metal (anode).
The impress current is the result of the transfer of ions due to the difference in voltage reference between the magnesium mass and the second electrolytic pole (copper coating).
The current is direct (DC) and compatible with other metals since it is naturally generated.
The negative charging of the protected metals is completely satisfactory, resulting in the surface which used to be anode of galvanic element (i.e. negative oxidizing pole) becoming cathode of electrolytic cell (i.e. negative reducing pole).
The protected surface remains negatively charged but its action is reversed and is now inclined to undergo reduction instead of oxidation.
The impress current must be above 0,8 volt but it must not exceed 10mA.
There are several advantages of this device compared to other methods. Here are some of them:
• The device is totally self-contained and does not require an external power source to function.
• It does not require monitoring, maintenance or repair because when the anode mass is exhausted, it simply stops being effective and is discarded.
• It does not pollute the environment.
• It is completely safe.
• It is not affected by weather conditions or any other circumstances.
• It does not come into contact with liquids and if connected to any water supply it does not come into direct contact with drinking water.
• It provides consistent voltage and amperage throughout its lifespan.
• It provides long term protection.
• It is affordable due to low manufacturing costs.
• Fitting it does not require any technical skills whatsoever.
• Any modification, intervention or alteration in the installations where the device is fitted in unnecessary.
• Its cathodic protection is completely compatible with other metals since magnesium is a very active metal whose naturally generated voltage is imposed on all of the other metals.
• It protects extended surfaces compared to other methods available.
It has been observed that several installations present specific challenges as a result of their technical specifications, the nature of the materials inside the pipelines or the composition of the soil in their location. Therefore, given the demands of metal surfaces for increased amperage or voltage, the device has been improved with the introduction of the STOPCOR PLUS product line, designed to provide increased impress current density.
Using this particular method the anodes are capable of providing current density of up to 100 mA per device, thereby increasing the amperage of the impress current and providing protection of metal surfaces on a much wider scale. Moreover, the protective action is powerful even in cases of metal surfaces coming in contact with acid fluids.
Depending on the composition of the soil, installations in some areas have been known to absorb part of the impress current of anodes. As a result, the voltage of the impress current falls below 1 volt.
In order to increase the impress current to the appropriate levels we rearrange the configuration of the device sequentially, thereby achieving the desired effect.
As for metal constructions surrounded by water, (i.e. ships) the grounding rod must be immersed in the water. This is achieved by a bar of copper underneath the ship. Although constantly immersed in the water, it is insulated so that there is no conducting contact with the ship’s hull. This bar is the grounding surface of the ship on which all the electrical grounding is attached. Finally, constructions equipped with a closed cooling circuit, (i.e. vehicle engines) grounding is achieved by an electrode component which is fitted on a point of the circuit constantly run by water. This electrode comes with en external pin which is connected to the cathodic protection device on the upper side using a clamping bolt.
This pin goes through the electrode and is inserted in the material while being insulated so as to keep it fixed and ensure the sealing of the closed circuit.
The metal used in the pin is either titanium or niobium in order to avoid oxidation.