LONG-LIFE HYDRAULIC FLUIDS
A Long-life hydraulic fluid may also be referred to as HV/HVI (high viscosity index) fluid. These products may be based on highly refined mineral base oils or even synthetic bases.
The key differences between a standard mineral hydraulic oil and a long-life product are:
· Higher viscosity index (rate of change of viscosity relative to temperature). Standard hydraulic oils typically have values around 100, whilst HV/HVI products are generally over 160
· HV/HVI products are more expensive than standard hydraulic oils
· They generally last 2-3 times longer than a standard hydraulic oil under the same conditions (TOST test ASTM D 943)
When evaluating a long-life product, the following parameters should be considered:
· FZG load test (ISO 14635, DIN 51350)
· Air release (ASTM D1401)
· Demulsibility (ASTM D 3247)
· Viscosity index (ASTM D 2270)
The key advantages of using long-life oils in a hydraulic system are as follow:
· Better cold start
· Superior operation at high temperatures
· Significant energy/fuel savings
· Faster cycle times (increased productivity)
· Less frequent oil changes (increased productivity, lower costs)