 |
 |
 |
 |
 |
|
|
|
|
|
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
|
|
 |
|||||||
|
For marine (sea water) application anodes are generally of Zinc or
Aluminium while for fresh water and sub soil applications Magnesium
anodes are preferred. Sargam offers a wide range of both Zinc and Aluminium
anodes in different shapes, sizes and weights to protect ship hulls,
ballast tanks, jetties, wharves, pipelines and offshore structures.
Sargam's anodes are type approved by Lloyd's Register of shipping, London.
Sargam is also an approved supplier of anodes to Indian Navy and holds
the necessary technology for this purpose from the Naval Material Research
Laboratory. Sargam's anodes are made from high purity raw material under
controlled conditions in dedicated furnaces. Its sacrificial anode manufacture
is ISO 9001/2000 certified. Sargam also offers top quality Magnesium
anodes made under inert atmospheric conditions for better quality and
finish. These anodes can be supplied with back fill chemicals as required.
Sargam, through its Singapore branch and through a network of associates
worldwide can supply anodes and other cathodic protection products in
various parts of the world including Singapore, Middle East, China and
Europe. Sargam's technical team can provide complete assistance in designing
a suitable sacrificial anode or ICCP system for various applications.
It can also undertake inspection of vessels and structures in India
and in Singapore. QUALITY CONTROL Both aluminium and zinc anodes are used in cathodic protection of ships. Zinc was the first material to be so used and is therefore considered the traditional anode material. However, aluminium has several outstanding advantages and is fast becoming the anode material of choice. The efficiency of any anode material depends on its electrochemical properties. First among these is the open circuit potential. For aluminiurn the open circuit potential is 1.07V with respect to Ag/AgCl while for zinc it is 1.0V This translates to a better driving potential for aluminium anodes which means that for the same anode configuration, aluminium anodes can deliver 30% more current than zinc anodes. Secondly, the current capacity of aluminium anodes is 2500 amp. hr/kg. as compared to 780 amp. hr/kg. for zinc anodes. Higher the current capacity, lower is the consumption of the anode and hence, consumption rate of the anodes in kgs/amp. yr is of the order of 3.4 kgs. for aluminium anodes compared to 11.5 kgs. for zinc anodes. Thus, aluminium when used as an anode material, because of its higher electrical capacity and lower density, translates into lesser weight and/or lesser" anode numbers and offers tremendous economies with improved performance. The only restriction is that in oil carrying cargo tanks the use of aluminium anodes is restricted to a height where the potential energy of the anode is less than 28 kgfm. ANODE SELECTION The tables of various standard sizes and weights of aluminium, Zinc & Magnesium anodes are given under each of items seperately. The sizes and weights are nominal. The choice of the sizes and weights depends upon the surface area to be protected and other factors such as duration of protection, types of coatings, presence of shadow areas, etc. In the case of cargo and ballast tanks, the types of cargo to be carried and the time that the tank is in ballast should also be taken into account. Having determined the number of anodes, it is important to ensure that their distribution is effective. Assistance can be provided by Sargam Metals in designing a cathodic protection system,choosing the number and types of anodes and also advising on their distribution. INSTALLATION Anodes are normally welded or clamped into position using the steel core. For the anodes to function effectively the resistance to current flow should be minimum in the contact area. This means that paint, scale, rust, etc., should be totally removed, especially where bolts and clamps are used
|
|
