HYDRAULIC OIL Photo:
HYDRAULIC OIL Photo: Komatsu/Kuhn Schweiz AG INNER VALUES PAY OFF Inner values are especially important when it comes to lubricants. What at first seems to be the cheapest hydraulic fluid often turns out to be the costliest once quality is considered. MOTOREX COREX HV multigrade hydraulic oils combine a large number of advantages that definitely pay off. This brass sliding block, one of several in a multi-piston pump, has sustained damage due to excess water in the hydraulic fluid (cavitation due to insufficient additives). No other mechanical system bears such extreme loads as a hydraulic system. Moreover, the trend in modern systems is for ever smaller hydraulic components to sustain vastly increased system pressure, requiring top performance at all times. Operators with a long-term mindset use top-quality multigrade hydraulic fluids from the MOTOREX COREX HV line in their hydraulic systems. IT’S ALL ABOUT THE ADDITIVES When it comes to composition and quantity of additives, many hydraulic fluids have the minimum needed to meet the manufacturer’s specifications – and it shows in their seemingly low price. Operators who prefer a modern way of working – conserving fuel and resources and minimizing equipment wear – use a COREX HV (high-viscosity) hydraulic oil with multigrade characteristics. COREX HV is built on a solid foundation of selected paraffin-based base oils and a high-performance bundle of additives. Viscosity index (VI) enhancers with extreme shear stability ensure a high viscosity index (see chart on page 9) and hence a flat viscosity-temperature curve. This measurably reduces penetration time, which in turn lowers wear and fuel consumption. The multigrade characteristic, along with the all-important protection against wear at high temperatures, keeps working even during long, heavyduty service (stay-in-grade performance). Moreover, COREX HV fluids provide solid protection against oxidation and are compatible with all non-ferrous metals. HYDRAULIC BREAKDOWNS ARE COSTLY Hydraulic components on work machinery and hydrostatic drives are everywhere these days. This makes 8
Low temperature range/cold COMPARISON OF VISCOSITY CHARACTERISTICS High temperature range/hot 4000 6.2 116 ˚C 130 ˚C 3000 Standard ISO VG 46 hydraulic fluid 5.2 Viscosity in mm 2 /s 2000 1000 * COREX HV ISO VG 46 −12 ˚C −2 ˚C Viscosity in mm 2 /s 4.2 3.2 COREX HV ISO VG 46 Standard ISO VG 46 hydraulic fluid 5.2 −24 ˚C −18 ˚C −12 ˚C −6 ˚C 0 ˚C 6 ˚C 12 ˚C 18 ˚C 24 ˚C Upper viscosity limit Hydrodynamic risk range/cold, hot Available working range 2.2 100 ˚C 106 ˚C 112 ˚C 118 ˚C 124 ˚C 130 ˚C 136 ˚C 142 ˚C Lower viscosity limit Standard ISO VG 46 hydraulic fluid MOTOREX COREX HV ISO VG 46 MULTIGRADE FLUID The chart shows a comparison between a monograde standard hydraulic fluid (gray) and a multigrade COREX HV ISO VG 46 fluid (yellow). It clearly shows that MOTOREX COREX HV ISO VG 46 enters the specified viscosity range earlier in cold temperatures (at −12 °C) and remains in it for longer in hot temperatures (+14 °C). hydraulic breakdowns due to excessive wear or extreme temperatures all the more aggravating. Single-grade hydraulic oils, which are difficult to pump at below-zero temperatures, not only cause burst hoses but can also damage costly hydraulic components such as pumps, valves, etc. During heavy use, single-grade hydraulic fluids heat up disproportionately. The oil becomes too thin and performance declines as wear grows more severe. The cost of damage from wear or of breakdowns soon adds up. Thus from a pure bookkeeping perspective, switching to a multigrade hydraulic fluid with adequate additives is entirely profitable. OPTIMIZED EFFECTIVENESS COREX HV’s exceptionally stable molecular structure and high shear stability also have a positive impact on pump efficiency. Thanks to its flat viscosity-temperature curve, pumps always operate in the optimum range. Special high-tech additives are designed to fine-tune the hydraulic fluid’s properties, creating a perfect seal in the pump. This reduces pump leakage and enhances the efficiency of the entire hydraulic system. The benefits are especially clear with hydrostatic drives such as those used in municipal equipment when starting under a load. Axial piston pumps in these drive systems work with especially high pressures of up to 400 bar! FRUGALITY DONE RIGHT Operators who use a COREX HV hydraulic fluid in place of a standard single-grade oil are not only being thrifty where it counts, but also protecting the environment by • reducing fuel consumption • reducing emissions • reducing wear • reducing downtime due to breakdowns • reducing performance losses in the system A very interesting, if challenging, topic (see also p. 17). The specialists from Technical Customer Service and your MOTOREX partner will be happy to provide qualified answers for all your needs. • Extreme temperatures and pressures really put hydraulic pumps to the test. Photo: Bosch-Rexroth motorex Magazine I July 2012 9
