Answer
A - Basic principle on which MGPS runs is electrolysis. The process involves usage of copper, aluminum and ferrous anodes. The anodes are normally fixed in pairs in the main sea chest or in such place where they are in the direction of the flow of water.
The system consists of a control unit which supplies impressed current to anodes and monitors the same. While in operation, the copper anode produces ions, which are carried away by water into the piping and machinery system. Concentration of copper in the solution is less then 2 parts per billion but enough to prevent marine life from settling.
Due to the impressed current, the aluminum/ferrous anode produces ions, which spread over the system and produce a anti corrosive film over the pipes, heat exchanger, valves, refrigeration and ac unit etc, internally.
MGPS anodes are fitted with specially designed safety cap which helps in removing the anode for replacement on board ship. Normally MGPS have a design life which may coincide with the dry dock of the vessels.