Case story


Chemical plant


EN 14917

Belman provided a remarkable Expansion Joint solution for installation in a chemical plant in Europe. This Expansion Joint is installed between a scrubber and a saturator.


The client needed a replacement Expansion Joint for an existing one that had reached the end of its service life. The client was very satisfied with the design and needed a supplier able to manufacture an identical piece. They therefore turned to Belman, as we specialise in custom solutions and are capable of designing and producing almost any Expansion Joint type, no matter how complex its construction may be.



Bellow with purge nozzles to avoid media settling

In this case, the client had a remarkable Expansion Joint design installed, which involved a bellow with purge nozzles to avoid media settling. Belman’s job here was to design and produce an identical part, which we were happy to do.

As this Expansion Joint is installed between a scrubber and a saturator and therefore directly onto the equipment, very special flanges were needed. The Expansion Joint has a loose flange at one end and a fixed flange at the other end to ensure a torsion-free installation.

The client specified a maximum spring rate, as they wanted to reduce the force transferred to the connected equipment. Due to modern production technologies Belman were able to meet even lower spring rates than those specified, for the benefit of the client.

The Expansion Joint is made entirely from material 1.4435 (AISI 316L) at the client’s request. EN 1.4435 is preferred due to its low carbon content and its ability to resist intergranular corrosion. The special purge and heating nozzles are made from 1.4301. The flanges are designed with thick walls due to the elevated test pressure. Besides the purge and heating nozzles, the Expansion Joint is also designed with a very special inner sleeve.


Special Expansion Joint construction with purge and heating nozzles to avoid media settling in the bellows

The Expansion Joint is installed horizontally. The melamine media, a mixture of ammonium, carbon dioxide and melamine (NH3/CO2/melamine), can become slightly solid at low temperatures. As this mainly becomes an issue at the bottom end of the convolutions, a special inner sleeve construction was made. To facilitate this, three steam purge and heating nozzles were required. By blowing steam into the bottom of the Expansion Joint, the critical areas are heated up, thereby keeping the medium at an acceptable temperature. This is not relevant for the upper area of the Expansion Joint, as the media cannot settle in the convolutions here. This prevents the media from settling in the bottom of the convolutions, which would damage the Expansion Joint and preventing it from working as intended.


Special transport bars

To ensure the Expansion Joint had the correct installation length to fit into the gap in the pipeline upon arrival at the chemical plant, Belman mounted some special transport bars for pre-tensioning during transportation. To avoid welding too many special lugs into the Expansion Joint that would offer no use afterwards, special threaded holes were made in the large flange (which only went part-way through) for mounting the transport bars. The special transport bars will be removed after installation.


Belman – expertise on highly customised Expansion Joints

Belman has engineered special Expansion Joint solutions to avoid media packing up for decades. Since 1994, we have supplied clients across different industries worldwide with remarkable designs. Throughout the years, Belman has supplied numerous Chamber Expansion Joints, also known as Jacketed Expansion Joints. In this design, an Expansion Joint is constructed with another larger Expansion Joint mounted around it to form a chamber between the two Expansion Joints. The medium flows through the inner Expansion Joint while a heating medium, such as oil, flows into the chamber between the two Expansion Joints. The heated oil flows through the chamber via an inlet and then an outlet. Belman has also engineered Expansion Joints with the convolutions designed and formed with wide open angles to avoid media from packing up in the bellow. These are just some of the many engineered solutions Belman’s expertise can offer.