Can oil maintenance save costs?
	Hydraulic technology has become well established in all fields of mechanical engineering. Its capacity to generate a high power density within a small space, its direct action on the actuator without complex kinematic chains and its excellent controllability are clear advantages both for mobile machinery and industrial plants. However, it can often cause problems when it comes to machine failures. Modern diagnostic systems are still in their infancy or simply too expensive, while manual on-site diagnoses are complicated and call for highly qualified maintenance personnel. A universal recipe for effective cost management is preventive maintenance. Once again, however, this depends on the availability of sufficient numbers of qualified specialists. Unfortunately, many of these have already been dispensed with in the wake of rationalisation measures. This makes it all the more important to seize every opportunity of saving on maintenance costs. From the maintenance perspective, hydraulic systems consist of two main parts: the pipe network including components such as pumps, valves or cylinders, and the hydraulic fluid. The latter comes in a huge variety of types, although over 75% of all hydraulic systems use mineral oilbased fluids. This medium is the “blood“ of the system: as in human beings, it is important to stop harmful substances from getting into the circulation. On the other hand, like blood the fluid can tell us important things about the operating status of the system. Accordingly, RT-Filtertechnik has long specialised in comprehensive oil maintenance strategies and related services based on its core competence of filtration. It is after all well known that approx. 70% of all machine failures are caused by solid impurities in the hydraulic oil. The first step towards optimal maintenance is therefore a good filtration strategy. Half the battle is convincing the machine manufacturers: time and time again, cost considerations cause the filter to be regarded as a necessary evil rather than an integrated system within the hydraulic unit. Consequently, it may pay to have your stock of machinery checked by filter experts, as even minor modifications can make a huge difference. Even machines with good filtration systems can still benefit from additional measures. Users of mobile filter systems equipped with RT filters report a significant increase in the useful life of their hydraulic oil, for example. Such apparatus has a wide range of uses: Bypass filtration during maintenance work (e.g. construction machinery, plastic injection-moulding machines) Filtration during filling from the barrel Flushing of the system following damage to a component (e.g. pump) Permanent bypass fil-tration in the industrial sector (e.g. presses, paper machines, plastics industry) The RT filters designed for these tasks have filter elements with filtration grades of 3 µm or 5 µm and highly efficient magnetic separation. There are also filters available allowing three-stage separation within the same housing. The oil purity thus obtained is well above the component requirements and helps to prolong the service life of both components and oil. There is frequent controversy over whether or not microfiltration can damage the oil. Oil manufacturers will deny this unanimously. However, experience shows that caution is called for here. Accordingly, RT provides a comprehensive advisory service and always suggests the optimal solution for the job in hand, without assuming that what is technically feasible is necessarily best. These measures can significantly reduce the contamination of the oil with solid particles. This in turn reduces the consumption of additives and prevents particles from multiplying multiplying through abrasive wear. A further lifetime-influencing factor in hydraulic systems is water. In some cases, e.g. where bio oil is used, even the water content has to be strictly monitored. Water invariably has an adverse effect on components and reduces the useful life of the oil. In combination with the above mentioned filter units, it is possible to keep the water content under control as well. RT water monitoring filters are modern elements consisting of glass-fibre materials and highly effective hygroscopic particles. The measures described so far cannot influence the chemical structure of the oil, however. Yet properties such as the viscosity, VI index or neutralisation number are important indicators for the oil ageing process and operating status. This makes it all the more important to have the process fluid checked at regular intervals. Oil sampling is particularly important in hydraulics. Even the tapping point should be determined on the basis of competent advice, and the sampling procedure can be demonstrated on site, e.g. by RT-Filtertechnik. A detailed oil analysis provides information on the following: Viscosity, VI index Neutralisation, pH value Additive content and consumption Metal content Impurities Purity class Water content Thermal load At first, regular oil inspections plus additional filtration measures will mean extra costs for the user. However, such an optimisation project with RT-Filtertechnik will certainly bring quick results in terms of a much longer lifetime for both components and oil and far fewer machine failures. What’s more, regular checks make it possible to schedule necessary maintenance jobs at convenient times. Needless to say, the RT laboratory is also available when the damage has already been done, and has already revealed foreign bodies (corrosion preventive, bio oil, etc.) to be the cause of many a blocked filter element. In the long run, therefore, it pays hydraulic users in particular to get full advice from the filter experts.