In every hydraulic system there are energy losses in the form of pressure and leakage losses in varying degrees. A differentiation is made between (Figure E 31):
- pressure losses in lines due to friction and flow deflection,
- pressure losses in valves as well as accessories, such as filters and coolers,
- Pressure losses due to throttling, which on constant pressure systems are particularly high,
- Leakage losses at the points that must be sealed.
All these losses are converted into heat that is absorbed by the oil and housing. On systems without appreciable throttling approx. 15 % can be expected on average, while in throttle circuits the loss element can be 25 to 30 % and higher.
Figure E 31: Losses in a hydraulic system