Arranging extra protection for your seals (3): dirt barrier and cathodic protection

In previous blogs we mentioned that Lagersmit can enhance and customise your seal with a wide range of options, such as wire winders and net cutters and the Distance Ring and HML Liner Coating. In this blog we highlight other options to protect your seal even further. Would you like to avoid damage to the aft seal caused by sand and debris, or prevent small fishing lines from entering the seal? Or do you need to ensure improved corrosion protection on your liner with extra anodes? Find out how these options will deliver you peace of mind!

Dirt barrier

The sand barrier works as an axial lip seal. The dirt barrier (picture 1, position 5) is tightened on the liner, by a strong pre-tension of the lip seal itself and the pressure on the sand barrier. This is achieved by the stainless steel spring and the water pressure. Because the sand barrier is fixed on the liner, it rotates and seals against the end ring, preventing sand or other abrasive particles from entering the seal.

Picture 1: Cross- section of a seal

Cathodic protection

Corrosion is an important issue with regard to the maintenance of the vessel. You can choose extra anodes to deliver improved corrosion protection on your liner (picture 1, position 2). The anode attached to your vessel or seal is used to prevent galvanic corrosion on the metal parts of the vessel. This form of corrosion occurs when two different types of metal in a conductive liquid (such as water) come close together. Read more about other solutions preventing corrosion on your seal.

There are several types of anodes. The traditional zinc anodes contain percentages of highly toxic cadmium, a heavy metal which is becoming increasingly restricted and regulated in use and disposal. Therefore, vessels have to change from zinc to aluminium or magnesium anodes according to the VGP. The choice between materials depends on where your vessel operates; aluminium anodes are suitable for salt water and magnesium anodes for fresh water. If zinc was used after the first dry docking after 19 December 2013, then the reasons why aluminium was not selected need to be properly documented.

Anode block

Lagersmit provides environmentally friendly anodes that will ensure you comply with the VGP directives, so we can supply aluminium anodes at your request. Contact us for more information.

WANT TO KNOW HOW WE KEEP YOU GOING?

Get in touch with Bart van Lee if you’d like to learn how we can enhance and customise your seal further!