March 2019

Focus on: Seals, Bearings & Lubrication Process, Controls & Plant March 2019 www.pwemag.co.uk Plant & Works Engineering | 31 stainless steel bearings are a better option. In fact, these are commonly recognised as marine grade bearings. Despite this, they should only be used in marine applications above the water line, or in flowing, oxygenated water. Full ceramic bearings made from zirconia or silicon nitride can provide even higher levels of corrosion resistance and are often used fully submerged. Bearings might seem a small thing considering the scale of many offshore rigs. However, failure of even the smallest bearing can bring operations to a grinding halt — a costly risk for a multimillion-pound industry. Ensuring quality and compliance Material is not the only factor to consider when choosing a bearing for use on an offshore oil or gas facility. Customers should also enquire about other technical capabilities, such as the load rating and tolerances of a bearing to ensure it can withstand the environment in which it must operate. Environmental responsibility, such as adherence with the Restriction of Hazardous Substances (RoHS) directive should also be considered for electrical and electronic equipment at these sites. Adhering to these regulations ensures that the operations will comply with increasingly stringent environmental regulations for offshore rigs. When checking this, it is also worth investigating whether the bearings used comply with other standards, such as those related to quality control. ISO 9001 and ISO14001 are noteworthy standards to look out for. Naturally, it is not essential to choose the most expensive bearing on the market but selecting a high- quality bearing could save on repair and maintenance costs in the future. Minimising maintenance Reducing the need for maintenance saves time, money and risk to any onsite maintenance engineers battling the elements. But, how can small components contribute to maintenance reduction? When selecting a bearing, customers should ask for the predicted lifespan of the bearing. In addition, are the bearing materials and lubrication suitable for a marine environment? Can the bearing run unlubricated with an acceptable lifespan as in the case of full- ceramic bearings? These are important considerations when specifying bearings that will run continuously with little or no maintenance. That said, the lubrication requirements will depend on the specific application of the bearing, its load and the conditions in which it will operate. Some bearing lubricants, for example, are not very water resistant and may eventually be washed out of the bearing in a wet environment hence the increasing use of full-ceramic bearings in marine environments. Other lubricant specifications, such as viscosity and speed rating, can also have a knock-on effect on the lifespan of a bearing. However, requirements for this can only be determined according to the exact application in which a bearing will be used. Oil rigs are vast facilities, and not every bearing will be the same. The unforgiving conditions of offshore oil and gas rigs can wreak havoc on the machinery used on these sites. However, there are ways to ensure that, even the smallest of components, can assist and not hinder the smooth running of these difficult facilities. For further information please visit: www.smbbearings.com