Often a client will experience a problem with a machine during operation that causes an alarm, trip or the machine will continue with run but with abnormal conditions. The other common scenario is a client that is unable to reach operational speed or load after an overhaul due to temperature or vibration limits. Understanding these and the failure mechanisms and the scenario for the conditions can help inform when to shut down machinery.
Modernising or revamping of old turbomachinery to improve efficiency can lead to babbit bearings needing to be re-rated within the same working package as the original design. We have experience in re-rating and upgrading bearing designs to allow for increased load, improved stability and lower running temperatures.
A bearing is a sacrificial component and its failure means the rotor was hopefully protected against any damage. However a bearing failure is usually related to an issue with the equipment such as vibration, oil contamination, whirl, misalignment etc. We can provide our extensive technical experience and support to identify the root cause of a bearing failure.
Whitemetals (also known as Babbitt) are alloys, typically tin based but some applications will use a lead based alloy. Tin based alloys are made from tin, antimony, copper and sometimes contain additives such as cadminium. The common standards in use are BS3332 and ASTM B23. The most common alloys are shown below.
|Grade||Tin (Sn)||Antimony (Sb)||Copper (Cu)||Lead (Pb)||Cadminium (Cd)|
|BS3332-A||Balance (89%)||7-8%||3-4%||0.3% max||0.05%|
|BS3332-B||Balance (88%)||7-8%||3-4%||0.3% max||0.8-1.2%|
|ASTM B23 Grade 2||88-90%||7-8%||3-4%||-||-|
|UNI 4515-MB80||79-81%||10-12%||8.25-9.75||0.35% max||-|
|JIS H5401 WJ2||balance||8-10%||5-6%||-||-|
Oiltech Bearings offers training in bearing principals, inspection, operation and troubleshooting. This course is normally provided on-site for our clients. If you are interested to arrange training with, please get in contact.