HYDAC FILTER SYSTEMS OLF-5 Series - Observing;Calculating Pressure Loss; Fig. 16 Pressure Loss Formula

5 | Mounting/installing HYDAC FILTER SYSTEMS GMBH
48 / 100 MoWa OLF-5 3433222d en-us print
5.3 Observing/calculating pressure loss
The pressure loss in a hydraulic line depends upon:
– Flow
– Kinematic viscosity
– Pipe dimensions
– Fluid density
The pressure loss can be estimated as follows for mineral oil-
based hydraulic oils:
Fig.16: Pressure loss formula
Δp Pressure differential [bar]
L Line length [m]
d Internal pipe diameter [mm]
Q Flow [l/min]
ν Kinematic viscosity [mm²/s]
D Density [kg/dm³]
The mineral oil-based hydraulic oil has a density of ≈0.9kg/
dm³.
This formula applies to straight pipe runs. Particularly with re-
gard to the suction side connection, note that additional con-
nectors and pipe bends increase the pressure differential.
Observe the following points for hydraulic connection:
– Keep the height difference between the pump and the oil
level in the reservoir as small as possible.
– Use a suction hose that is suitable for a vacuum of ≥
-0.5bar (e.g. -1 bar).
– Avoid constrictions in the connected hoses. This reduces
the power and increases the risk of cavitation.
– Note that the nominal size of the connected hose/piping
must correspond to the cross-section of the connection
thread.
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