Case story


Passenger ship

Baltic Sea


Over the past years Belman has designed, manufactured and supplied numerous Expansion Joints for scrubber systems on board all kind of marine vessels such as cruise liners, container ships, ferries and freighters. This latest batch of 8 Expansion Joints were delivered for the scrubber system on a passenger ship.


Scrubbers to clean exhaust gases

Scrubber systems can be referred to as scrubbers, wet gas scrubbers, exhaust gas scrubbers among many other different terms. No matter which term is in use, the scrubber has the same purpose – to control air pollution by cleaning the exhaust gas. In this way vessels can comply with the permissible emission limits in low emission zones.


Role of the Expansion Joints

As the scrubber can be susceptible to damage from vibrations and movements, the installation of Expansion Joints is required to protect the scrubber and connected equipment. The Expansion Joints are therefore placed at different locations around the scrubber. No two scrubbers look exactly the same and are designed and manufactured in many different ways. In most cases an Expansion Joint is placed at the inlet and a second one is positioned at the outlet.


Expansion Joints for different scrubber designs

No matter what the design, Belman excels in customizing the Expansion Joints for the exact scrubber specification, such as demonstrated in this passenger ship project. The Expansion Joints for scrubbers are typically made from 1.4541 or 1. 4404 (most often located at the inlet) and 254 SMO or duplex or super duplex – these materials are often specified when sea water is used for cooling (most often located in the outlet). The media and the operating criteria of the process/scrubber of course determines the material of the Expansion Joints. The exhaust gas that is fed into the scrubber is dry and heated and therefore AISI 316L is sufficient. However, when the media exits the scrubber it has cooled and can be wet/humid with acidic properties. For these reasons the Expansion Joint is made from 254 SMO and since the media in most situations has the possibility to run-back the Expansion Joint is further equipped with an inner sleeve also made from 254 SMO.


Various sizes and types of Expansion Joints for scrubbers

The Expansion Joint type and size are determined by the design, dimensions and type of the scrubber and by the piping system, particularly the shape of the piping on the scrubber inlet and outlet. Likewise, the type of the Expansion Joint is selected by the amount of movements in the system. For most applications, the Expansion Joints used are single bellow or double bellow Expansion Joints with flanges. The movements they are to absorb are typically axial movements.


New and Retrofit Options

Belman design and manufacture Expansion Joints for both new build and retrofit projects. Our customers benefit from Belman’s product expertise and our ability to deliver customized solutions with short lead times.