Rubber Pump Bellows, Where are they used?
Rubber Bellows are primarily used on pumps, chillers, and other reciprocating machinery to reduce noise and vibration. They are a critical part of any pumping system as they provide the flexibility necessary to absorb system movements associated with vibration. Rubber bellows are also known as rubber expansion bellows and have the capability of compensating for small amounts of axial, lateral and angular pipe work movement and therefore makes them suitable for small installation misalignments. However, rubber bellows should not be used like a metal expansion joint to compensate for thermal pipe movement and for these types of application Stourflex would always recommend a specifically designed stainless steel expansion joint.
We are often asked what is the life expectancy of rubber bellows, however, there is no definitive answer and here’s why :-
On a typical LTHW system running intermittently at 3.5 Bar 82 degrees centigrade and installed at their normal supplied length, and not extended, compressed or offset we would anticipate a service life of between 5 to 10 years. However, if the system is running continuousely or the rubber bellows are subjected to elevated pressures & temperatures then the life expectancy is greatly reduced.
For these reasons we always recommend that all rubber bellows are periodically inspected for signs of deterioaration. This should include the removal of any insulation materials to allow a full inspection to be carried out. The removal of insulation can prove difficult, however, Stourflex offer a range of bespoke removable lagging jackets for this purpose. Flange bolts should be checked and re-tightened if required. Rubber bellows should never be painted as this may reduce service life and bellows should be inspected for any hairline cracks. Exterior surface cracking is most commonly the result of aging and/or elevated temperature. As rubber ages, it becomes hard and brittle and loses inherent flexibility and resilience. Hairline cracks in rubber bellows are a sign that the bellows are nearing the end of their service life and should be replaced as soon as possible.
Rubber bellows are an important part of any heating or chilled water system and should be inspected regularly as part of a maintenance program and consideration given to keeping a number of spares to reduce the risk of long term shut down.
If you have an existing installation you may well have numerous pump connectors of different types, different flanges, different manufacturers and different ages, maybe you have started to experience failures of the pump connectors as their end of service life is approached or exceeded. We can offer a site or plantroom survey and help highlight those likely to fail first and advise on a list of spares to carry that will help minimise your downtime and costs.
If you experience failures of the pump connectors on your new system, you may have the incorrect products or a poor installation, either way our comprehensive report will highlight any remedial actions that need to be taken to get your pump connectors operating optimally as well as advise on long term maintenance.
Please contact the Stourflex Technical sales team to discuss your applications and or to enquire about out site surveys.
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