Safetech, more than 30 years experience in the manufacture of multiple convolution expansion joints
What are they for?
These multiple convolution joints are designed to achieve the movement and rigidity requirements specified in the stress calculation of piping systems in any application/facility. Their purpose is to compensate for misalignments detected either due to temperature variations or due to vibrations and movements. A common example is the misalignment that often occurs between the duct and the inlet of a tank. Over the last few years, our technicians have faced numerous projects of this type involving a large lateral displacement.
What should be the maximum number of convolutions a joint must have at all times to preserve its stability?
The answer is eight convolutions up to size DN1200. For larger sizes, the operating conditions should be examined to determine the maximum possible number of convolutions based on this analysis. SAFETECH manufactures expansion joints from DN50 to DN3600.
In fact, we have the capacity to reach DN4000 sizes. However, the largest joints manufactured so far in our facilities have been DN3600x450, requested for the water intakes in thermal power plants.
Who takes part in the development and production of a multiple convolution joint?
The manufacture of multiple convolution joints is now part of our daily work routine. One of the clients who benefit most from our know-how are the EPCs (ENGINEERING, PROCUREMENT & CONSTRUCTION), which we support and advise regarding the design of this type of bellows and, in addition to this, in improving the performance of their facilities. At least three profiles are involved in the development and production of a multiple convolution joint at different stages:
The time between a customer’s order being placed with us and being delivered to their premises will depend on the volume of multiple convolution joints ordered. For a tied expansion joint, it would be about four weeks. The average lead time for an EPC (here the number of bellows ordered is generally high) is usually between 12 and 16 weeks. However, we have the resources to adjust deadlines if necessary, considering that an urgent need for spare parts is not the same as the time needed to develop a new project.
Annual visual inspections must be carried out starting in the fifth year of operation to ensure that the multiple convolution joints are in good condition and that they are free from defects, such as:
- External cracking or damage. Changes in the outer cover of the joint, which may be indicative of serious deterioration.
- Convolution flattening
- Cracks at the convolution base and/or at the flange lower area.
- Deformation and separations between the layers.
- Leaks
