Hydraulic Oils - Systems & Fluids
Hydraulic oils, also called hydraulic fluids or liquids, are the medium by which power is transferred in hydraulic machinery. Most hydraulic fluids are based on base mineral oils, examples of equipment using hydraulic fluids including excavators and backhoes, refuse trucks, aircraft, elevators and other industrial machinery. However, many devices also use hydraulics in their braking, power steering systems as well as some automatic transmissions.
One characteristic that all Hydraulic Fluids must have, if they are to work most efficiently, is that of low compressibility.
Whilst the primary function of any hydraulic oil / fluid is to convey power within in the hydraulic system there are other important functions that must be considered.
One of the most important issues that hydraulic oils must address is the protection of the hydraulic systems components themselves.
The Functions of Hydraulic fluids
The major functions of hydraulic fluids together with the properties that it needs are listed below:-
Hydraulic Fluids Functions
& Properties
|
Function
| Property |
| Medium for power transfer and / or control |
- Low foaming tendency
- Low volatility
- Low compressibility
- Fast air release
|
| Heat Transfer
Medium |
- Good thermal capacity
- High thermal conductivity
|
| As a Sealing Medium
|
- Adequate viscosity
- High viscosity index
- Stability under Shear conditions
|
| As a Lubricant
|
- Viscosity for 'film maintenance'
- Low temperature fluidity
- Thermal stability
- Oxidative stability
- Hydrolytic stability
- Water tolerance
- Cleanliness
- Filterability
- Demulsibility
- Antiwear characteristics
- Corrosion control
|
| To Ensure Pump efficiency
|
- Appropriate viscosity to minimize leakages
- High viscosity
|
|
Special functions
|
- Fire resistance
- Friction modifications
- Radiation resistance
|
Choosing The Right Hydraulic Fluids & Oils
Choosing (or developing) the right hydraulic fluid for your hydraulic systems is vital, especially as some, typically industrial, hydraulic systems operate at hundreds to thousands of PSI and very high temperatures. In these cases severe injuries and death can result from any component failures.
Thus the utmost care must always be taken when performing maintenance on hydraulic systems and in the selection of the correct hydraulic oil.
As the choice of hydraulic oils is so wide and the differences and capabilities so great, at Exol we strongly suggest that you always ask the experts and exols experts are here to help you today.
Areas where Exol can Assist:-
- Hydrostatic Transmissions
- Hydraulic Suspensions
- Rexroth Hydraulics
- Hydraulic System Fluids
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