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Water transportation is one of the five major transportation systems, and ships are the main means of transportation. In recent years, the growth rate of seaborne goods has increased by 8% year by year. However, due to the long-term navigation at sea, the ship is corroded by various corrosive media. At present, the main anti-corrosion measures for ships are the combination of coating and cathodic protection. Due to the coating defects such as coating loss and porosity in the process of coating and application, corrosion will occur in these places first, which will accelerate and cause pitting corrosion. Cathodic protection can effectively inhibit the pitting corrosion of coating defects, reduce the current density of cathodic protection, make cathodic protection more economical, more uniform distribution of protection current and better protection effect.
For large ships, the protection current is relatively large. In this case, two independent protection systems can be installed in the middle of the ship or near the head and tail of the ship. Potentiometers can be installed in or near the main control room of the engine room.
When installing potentiometers, it should be noted that the cathode grounding and zero grounding of the reference electrode should not be at the same point, and should be separated by a certain distance. The negative pole of the potentiostat should be connected to the hull, and the positive pole should be connected to the auxiliary anode insulated from the hull.
The auxiliary anode is generally symmetrically arranged on starboard and starboard. Generally, 4-6 ships are suitable, and the number of super large ships can be increased appropriately, but not more than 10. After determining the number of anodes, the anode specifications can be determined. The auxiliary anodes installed at the stern are mostly strip-shaped and the bow are mostly disc-shaped. The vertical arrangement of auxiliary anode is about 1 / 3 of the arc length from heavy water line to ship bottom center line, but it must be less than 0.5 m of light water line.
There are two installation methods of marine auxiliary anode, one is attached type, the other is concave type. The advantage of the adhesive is that it has good dispersion, but it is easy to be damaged. The advantage of concave type is that the anode is not easy to be damaged, but its dispersibility is not as good as that of adhesive type. Concave anode is mainly used in icebreaker and other high load ships, and is installed in the bow.
The longitudinal arrangement of reference electrodes depends on the number of reference electrodes. If the whole ship has only two reference electrodes, one in the bow and one in the stern or middle of the ship, it is better to separate the left and right sides. If more than one reference electrode is installed, the bow, middle and stern, port and starboard can be configured. The reference electrode is arranged in the middle of the two auxiliary anodes or the farthest place from the anode, that is to say, it is installed at the place with the maximum potential. For large ships, the distance should be at least 15-20 meters away from the anode, while for small ships, the distance can be reduced proportionally. The reference electrode and auxiliary anode should be arranged in the same horizontal plane vertically.
Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services.
Tel: +86 17568010262£¬0539-3712117.