PANTOGRAPHIC
LINKAGE PIPE BELLOWS
FOR ABSORBING
LARGE MOVEMENTS

Belman has engineered and produced a 5-metre-long Expansion Joint solution for installation in an oil refinery in the Netherlands.

 

CLIENT ISSUE
The client turned to Belman for 1:1 replacement of an Expansion Joint, which it had delivered to them several years previously. The Expansion Joint solution was originally constructed and troubleshooted by Belman and had been operating successfully, so the client wished to continue with the same solution. The medium contains acids at the installation point in the CO2-line and the client was experiencing condensation issues here. This meant that it needed to replace the Expansion Joint as soon as possible to prevent damage to the pipeline. In addition, the Expansion Joint needed to absorb very large axial movement (+0/-240 mm) in this pipeline.

 

BELMAN SOLUTION – Pantographic Linkage Pipe Bellows
The Pantographic Linkage Pipe Bellows are made completely from austenitic stainless steel EN 1.4301 (AISI 304) with only the bellows, the inner sleeves and the lug being made from 1.4571 (AISI 316 Ti). The Expansion Joint is designed for very large axial movement and has a remarkable design. It consists of four bellows in sequence divided by a middle pipe. This construction basically works in the same way as two Expansion Joints, as each part of the Expansion Joint is not designed to absorb the same number of movements. The first set of two bellows is designed to absorb less axial movement than the other set of two bellows. As a total solution however, the Expansion Joint can absorb all the axial movement of +0/-240 mm. This design ensures smooth operation by enabling the Expansion Joint to absorb large axial movement and the pantographic linkage ensures that this movement is divided equally between each of the bellows. The inner sleeve acts as an aid to stability in the 2 x 2 bellows construction of the Expansion Joint.

 

What advantages are there to using Pantographic Linkage Pipe Bellows?
Expansion Joints can incorporate multiple numbers of bellows in one unit, depending on the movement they need to compensate and the installation environment. Multiple bellows in a sequence allow the absorption of very large movements. When several bellows are placed in sequence in an Expansion Joint, such as in this Pantographic Linkage Pipe Bellows, the challenge is to ensure that some bellows are not overloaded while others don’t contribute at all. The advantage of the Pantographic Gimbal solution is that it is designed and constructed to distribute the total amount of axial movement and divide it equally between each bellow. This prevents the premature wear-out of the bellows and thus ensures smooth operation. Pantographic Linkages can also be designed to absorb single and multi-plane lateral movements.

 

Special middle support assembly on the Expansion Joint
When installing Axial Expansion Joints into pipelines, it is important that the fix points are placed as close to the Axial Expansion Joint as possible. The sole function of the Pantographic Linkages is to distribute the movements. Therefore, in this case, the pipeline is fixed by a light fix point on a steel pillar, which is located behind the Expansion Joint just off-centre on the Expansion Joint. This means that the middle section of the Expansion Joint is attached to this pillar and the light fix point. The fix point is kept light enough that it won’t absorb the reaction force, which is absorbed instead by the fix points located at each end of the pipe section. To ease the installation, the client requested that a middle support assembly could be mounted on the Expansion Joint. Belman designed and mounted the middle support assembly accordingly.

 

Belman – expertise in highly engineered Expansion Joints
Since 1994, Belman has engineered over 900,000 Expansion Joints. Belman’s record of experience illustrates our expertise in handling technically complex projects for clients worldwide. Based on our Expansion Joint and Pipeline understanding, Belman manages and provides comprehensive Expansion Joint design projects from conceptual idea to design, manufacture and testing that focus on cost efficiency, reliability and safe operation.