Valves are the brains and pumps the hearts of hydraulic systems. Regular maintenance is critical to their good health. Lubricants also play a huge role.
Fluids that don’t control oxidation can lead to contamination and varnish, with varnished valves having a tendency to remain open. This forces the servo to work harder, and can result in failure.
Oxidation can be minimised by using new generation zinc free hydraulic oils.
To achieve a lubricant’s anti-wear properties, different types of additives are used. Zinc additives are the most common, but in harsh conditions can degrade to form sludge.
Leading lubricant suppliers have started to use zinc-free formulations in their hydraulic oils. These provide an equally robust protective film without the sludge issues – thus ensuring a cleaner system
Extending oil drain intervals may have several benefits including reduced inventory costs, operational risks and unscheduled downtime. However, this may be at the expense of accelerated oxidation.
Extending the oil drain interval without failure can only be achieved with the use of high quality hydraulic oils, balanced with the right additive technology.
As part of routine maintenance, the "health" of the hydraulic oil and the hydraulic system itself should be checked regularly. Typically, we advise quarterly oil analysis and annual system inspections.
There are two key ways to minimise leakages. The first is to undertake a complete hydraulic system inspection to locate and address leakages (e.g. renewing, changing or maintaining seals). This, however, requires considerable downtime.
The second, more efficient, method is to use a shear-stable, high viscosity index lubricant that has universal compatibility with a wide range of seals. For example, Mobil DTE 10 Excel’s high viscosity index level provides optimum viscosity in high ambient temperatures when leakages are more likely.