July/ August 2020

However, when you compare the criterion of laboratory tests for zinc- based hydraulic oils against the indicators of a poor-quality hydraulic fluid (oxidation in the presence of yellow metals, thermal instability and water and air contamination), and a high-quality hydraulic fluid (excellent thermal and oxidation stability) it is evident that these poor hydraulic oil test results aren’t reflective of zinc’s properties, but those of a poor-quality hydraulic fluid. In our latest whitepaper, ‘Are sludge and varnish killing your productivity?’, we explore how zinc-based technology in a high-quality hydraulic oil can in fact help to extend oil and equipment life and generate efficiency-based savings. For example, Shell Tellus S4 VE hydraulic fluid features low sludge- forming technology with wear and oxidation protection, meaning that it not only produces 15 times less sludge and four times less varnish than competitor mineral based oils during high-temperature Indiana Standard Oxidation Test (ISOT) testing [2] [3] , but it exceeds the Bosch Rexroth A2F10 piston pump test limit by four times [2] [4] . Significantly enhanced oxidation resistance is another benefit of high- quality zinc-based oils - a factor that plays a pivotal role in equipment service life. Consequently, Shell Tellus S4 VE was shown to last at least twice as long as competitor mineral oil in industry-standard oxidation tests [2] [5] . The oil also passed the Bosch Rexroth A2F10 piston pump test (JCMAS P 045), which evaluates oxidation stability in construction applications. To pass the test an oil’s viscosity change, acid number increase and sludge build up must remain the same, within the test’s limits. Shell Tellus S4 VE remained the same for 2400 hours, which is within the test’s limits. This strong oxidation resistance evidences the tangible impact high-quality hydraulic fluid can have on operational performance. Now is the time to take action By helping to limit the build-up of sludge and varnish deposits, high-quality zinc-based hydraulic fluids, like Shell Tellus S4 VE, not only mitigate the risk of unplanned downtime by preventing equipment overheating and valve and filter blockages, but help to extend oil and pump life and increase productivity by up to 6% compared with mineral oils [2] [6] . We are in a period of economic uncertainty and as such, improving TCO will likely be a priority for operators across the industry. With this in mind, it is crucial to dispel the myth surrounding zinc-based hydraulic fluids and focus on the determinants of a high and low-quality oil. Whether it’s through extended equipment and oil life or productivity increase, the benefits of using high-quality zinc-based hydraulic fluids to help avoid the build-up of sludge and varnish can make a significant difference at a time when businesses need it most. www.shell.com References [1] https://bfpa.co.uk/news/bfpa-members-support-the-nhs-during-the-covid- 19-pandemic/ [date accessed: 08.07.20] [2] Shell Lubricants ‘Are sludge and varnish killing your productivity? Could the latest oil technology give you cleaner, longer-lasting and more productive Hydraulic Systems?’ whitepaper. [3] High-temperature Indiana stirring oxidation test (ISOT) JIS K2514. This test is typically a compressor oil test and favours zinc-free chemistry. However, it is a good indicator of sludge and varnish tendency. The test promotes the oxidation of the lubricant by blowing dry air in the presence of heat (165.5degC), and metal catalysts (copper and iron coils). After 48 and 96 test hours, the used oil samples were forced through a paper filter to examine the sludge build-up. [4] Bosch Rexroth A2F10 piston pump test evaluates the oxidation stability of hydraulic fluid under high-pressure, dynamic conditions in situ. The test is part of JCMAS P 045. The oil temperature in the oil tank is 80degC and 1 L/h of air is supplied to the inlet pipe to cause cavitation in the pump. The JCMAS specification for change of viscosity and acid number and sludge is 500 h but the OEM requirement is 1000 h. [5] 6400 mL of each oil was kept at 195degC. Two samples per oil were used. Steel spindles were weighed and their masses were recorded. One steel S w i t c h Y o u r S w i v e l ® S w i t c h Y o u r S w i v e l ® Simpli昀ed hose con昀guration, less hose and adapters combine to reduce repairs and downtime cutting the overall cost of hydraulics. 1-763-784-5531 www.SuperSwivels.com No Kinks NoHoseTwisting • Available In 304 & 440 Stainless Steel • Rated To 10,000 P.S.I. • Heat Treated • Custom Design & SizesAvailable • Rebuildable Ball Bearing Design • Full Flow—Low Pressure Drop • Superior QualityAlloy Steel • Side Load Resistant Quality Products Made In The U.S.A. Patent No. 5547233 Fax: 1-763-784-7423 Email: sales@superswivels.com Available In BSPP Hydraulic Live Swivels Inline & 90° Heavy Duty Ball Bearing Design www.hpmag.co.uk HYDRAULICS & PNEUMATICS July/August 2020 23