Large dimension rubber expansion joints
- SAFETECH manufactures DN3600x450 rubber expansion joints and has the capacity to manufacture up to DN4000
- With proper maintenance our units can last more than 20 years
There are just a few facilities in the world with water inlet pipelines larger than 3 metres in diameter so orders to manufacture expansion joints for these are highly sought after. SAFETECH is proud to be well positioned, winning many of these valuable contracts year after year. Sometimes the expansion joints will be for a new facility – or it might be that a complete expansion joint or just the rubber bellow needs to be replaced at the end of its life. SAFETECH has the engineering design capability, technical experience, the capacity – and crucially – the experience. A typical application is a Thermal Power Plant where the expansion joints need to operate at 6 barg and full vacuum.
High water flow and low pressure
These large dimension rubber expansion joints generally have a high water flow rate (non-aggressive fluid) but low operating pressure, so when installed correctly and used under the conditions for which they were manufactured they should last at least 20 years.
Joints like these require a specialist manufacturer. Their sheer size presents significant challenges during manufacture and also in preparation for transport. The actual manufacturing process is largely similar to smaller joints but there are some important differentiators:
- High tooling cost.
- A large autoclave is required to vulcanize the joint.
- The manufacturing space needs to be sufficiently large and with easy access.
- Specialist transport will be required.
SAFETECH subjects all its expansion joints to strict monitoring throughout the manufacturing process. From design, through manufacturing, packaging and on to final shipment, we can offer on-request dimensional reports, pressure and vacuum testing. Rigorous quality control is the key to our very good customer service record.
Maintenance of rubber expansion joints is important. Visual inspections should be carried out annually from the 5th year of operation onwards checking that the rubber bellow is in good condition and that the following defects are not present:
- External cracking or damage. Changes in the outer cover of the joint may be indicative of serious deterioration.
- Any flattening of the convolutions
- Cracks at the base of the convolutions and/or at the base of the flange(s).
- Any deformation and/or separation between the layers of rubber.
Technical issues currently stand at just 0.1% of the thousands of expansion joints we manufacture each year. Of this small number, most of these issues are very small and easily rectified. And we work constantly to improve still further.
