MRFD7
Hydraulic connection of the MRF
HYDAC FILTER SYSTEMS GMBH
en
Page 21 / 36
BeWa MRFD7 3551097 us 2010-05-18.doc
2010-05-18
Notes on Piping / Hosing
In order to keep the pressure loss as low as possible, use as few threaded
connections as possible.
The pressure loss in a hydraulic line depends upon:
Flow
rate
kinematics
viscosity
pipe
dimensions
fluid
density
The pressure loss can be estimated for hydraulic oils as follows:
Δ
p
≈
6.8 * L / d
4
* Q * V * D
Δ
p = Pressure differential in [bar]
L
= pipe length [m]
d
= internal pipe diameter [mm]
Q
= Flow rate [l/min]
V
= kinematics viscosity [mm²/s]
D
= Density [kg/dm³]
Mineral oil-based hydraulic fluid has a density
of
≈
0.9 kg/cm³.
This applies to straight pipe runs and hydraulic oils. Additional threaded connections
and pipe bends increase the pressure differential.
Keep the height difference between the pump and the oil level in the tank as
minimal as possible.
Hoses must be suitable for suction pressures of at least -0.5 bar.
Constrictions in the connections and lines should be avoided. This could
compromise suction output and cause cavitation .
Take note that the nominal size of the connected hoses/piping must be at least as
large as the inlet port sizes.
Make sure that no tension or vibrations are carried over to the pump or filter housing
when the pipes are connected. Use hoses or expansion joints if necessary.
