Engineer News Network The ultimate online news and information resource for today’s engineer
Chris Johnson explains why ceramic bearings used without any lubrication is the best option for equipment used in cold and corrosive environments
Low-temperature reactions are widely used in pharmaceutical manufacturing.
Temperatures of approximately -80˚C are sufficiently cold for most cGMP requirements, but these extreme temperatures create design challenges for machinery components.
Pharmaceutical manufacturing, and its related equipment, require some of the most meticulously designed and controlled production processes in all industry sectors.
Therefore, equipment used in this sector should bolster efforts to improve safety, not oppose them through inappropriate design choices. This makes selecting the right bearings for pharmaceutical equipment vital.
Functionality
Only certain types of bearing material are suitable for use at low temperatures and high speeds, as commonly endured in pharmaceutical manufacturing.
Additionally, the extremely harsh solvents and chemicals used in these processes makes corrosion a real threat to plant uptime.
To overcome corrosion, it is often recommended that pharmaceutical machine builders invest in full ceramic bearings.
Severely low temperatures can dramatically increase the viscosity of lubrication, a vital consideration for those using bearings in these environments. Increased viscosity can make the bearing difficult to rotate, rendering it ineffective.
Ceramic is non-porous and as a result, it is practically frictionless. Unlike stainless steel bearings, full ceramic bearings do not suffer heat build-up within the bearing and therefore do not need lubrication to help dissipate the heat. This means full ceramic bearings do not require lubrication to run — which overcomes the issue of high lubrication viscosity at low temperatures.
Full ceramic bearings are the only type of bearing recommended to run dry at anything faster than very low speeds.
Hygiene
Bearings used in pharmaceutical manufacturing should also meet aseptic standards. When used in a pharmaceutical reactor, or other piece of equipment used in pharmaceutical manufacturing, unlubricated full ceramic bearings do not run the risk of contaminating the product due to lubricant leakage.
Full ceramic bearings are also fitted with non-contact seals which do not generate the higher levels of frictional torque associated with rubber contact seals. This and the lack of lubricant avoids the high torque commonly associated with bearings operating in low temperatures.
For such a small component of pharmaceutical manufacturing, there is a lot to consider before selecting a bearing. Getting the choice right is vital for maintaining the crucially high standards of pharmaceutical manufacturing.
To discuss bearing options for pharmaceutical applications further, get in touch with a reputable bearing supplier, such as SMB Bearings. The team can advise on bearing material, lubrication and seals, based on the requirements of the machine and control methods.
Chris Johnson, managing director of miniature bearing supplier SMB Bearings.
