Corrosion in these conduits can be due to various causes; some individual and others are collective. Various small sources of corrosion can jointly create a much bigger problem beyond the damage possible from a single source.
The variables that provoke corrosion are: the naturally occurring aggressiveness of saltwater, the velocity of the circulating water, galvanic pairs caused by mixes of various metals in the circuit (solders, naturally occurring tension in the pipe from manufacture, etc...), or uncontrolled erratic or vagabond currents that circulate through the pipes.
The first thing that must be done is to interconnect all the pipes or tubes through electric bridges to the ships ground. The aim then must be to use cathodic protection to stop the corrosion from the inside of the tubes or interchangers.
Traditionally, cathodic protection was achieved through the use of zinc or aluminum anodes that would be screwed into the conduit (½"Gas thread) and interspersed at various points along the pipe, giving more current to the aluminum anode than the zinc in the case that they were the same size (in industrial installations, as an exception, ¾" Gas threads could be used).
In the case when more precise current is needed per anode, or if we want longer duration of the anodes, it is necessary to use cathodic protection through impressed current. The Proytec system consists of Titanium anodes which can be placed in the same ½" Gas thread locations used by traditional anodes. There are various types of anodes, depending on the need for the individual system, which can output up to 500mA per anode and achieve a work life of up to 20 years.
It is necessary to feed the anodes positive current by means of a regulator that we offer in various power output ranges. The system allows the anodes to receive more current in situations that necessitate an increase such as when fluids circulate. This way the proper current will reach the anodes under all circumstances. The regulators used are the same type as those used for the hull and metal parts under water. The size and intensity of the regulator depends on the number of titanium anodes being fed in the water system.
The system comes equipped with a reference electrode that continuously indicates whether the protection if effective. Like the anodes, the reference electrode is installed in the tubes as well and must be in contact with the electrolyte (water) exactly the same way as the anodes.
