Shell Tellus Oils S
Zinc-free hydraulic oils for severe duty
Shell Tellus Oils S are 'top-tier', anti-wear hydraulic oils formulated to be the ultimate 'high reference oil' in the hydraulics industry.
Based on advanced 'zinc and chlorine free' technology, Shell Tellus Oils S are formulated to ensure exceptional performance in hydraulic fluid power trans-
mission systems subjected to severe duty.
Applications
* Primary application in industrial, marine and mobile hydraulic and fluid power transmission systems.
Performance features
* Outstanding oil life
Typically two to four times that of many anti-wear hydraulic oils.
* Peace of mind
Through longer component life and trouble free operation.
* Ecologically acceptable
Zinc and chlorine free formulations unique to Shell.
Long life
The length of a hydraulic oil's life depends mainly on its ability to resist oxidation due to
heat in the presence of air, water and metal catalysts such as copper. Oxidation results in the formation of sludge and acidic products.
A standard test of oxidation properties is the Turbine Oil Stability Test (TOST), in which the
oil is heated at 95°C in the presence of water and oxygen with copper and iron as catalysts.
The test results are expressed as time taken (hours) for the acid value to reach 2 mg KOH/g.
In this test, Shell Tellus Oils S have an oxidation life of two to four times that of many other anti-wear hydraulic oils.
Vane pump wear performance
Shell Tellus Oils S have been subjected to a number of vane pump tests which are some of the most severe for evaluating steel-on-steel
anti-wear properties.
Excellent performance has been achieved in the standard industry tests using Vickers (V104C and 35VQ25M) and Denison (T6-C)
hydraulic vane pumps. In addition, outstanding performance is also observed when applying Shell in-house test conditions. These test the
fluids over the complete range of pump operating conditions. The results have proven that Shell Tellus Oils S are capable of
providing the ultimate protection under the extremes of operation found in real service.
FZG gear rig test
Gear rig tests are sometimes used for evaluating hydraulic oils and the best known is the FZG rig (Forschungsstelle für Zahnräder
und Getriebebau - Technical Institute for the study of Gears and Drive Mechanisms).
The rig utilises a pair of specially designed case-hardened spur gears and, for hydraulic oils, it is run at a pitch line velocity of 8.3 m/s,
with an oil temperature of 90°C. The test is carried out by running the gears for 15 minutes
in the test oil then weighing the gears, after which the machine is reassembled and the load increased. This procedure is carried out until at least 10 mg weight loss is recorded between the stages,
or until the gears appear scuffed.
Many anti-wear hydraulic oils fail around the tenth stage but Shell Tellus Oils S easily exceed this performance level.
Thermal stability
An oil's thermal stability is the measure of its ability to resist degradation and attack of metals at high temperature. An accelerated
test for this is to maintain the oil at a temperature of 135°C for one week in the presence of steel and copper.
Tests with Shell Tellus Oils S show negligible weight changes of the metals, whilst the steel remains bright and there is only slight
discolouration of the copper; many anti-wear hydraulic oils cause the copper to become black.
Piston pump performance
Many piston pumps utilise brass components and in particular brass slippers which fit onto