Connecting up unit
Notes on pipes and hoses
NOTICE
Non-permitted pressure at the inlet IN / outlet OUT
Risk of malfunctions
►
Determine the pressure to be anticipated at the inlet/outlet with the
prescribed values.
Make sure that the cross-section of the connected hoses/piping is at least as
large as the cross-section of the inlet/outlet port sizes.
The pressure differential in a hydraulic line (
∆
P(line)) depends on the
following:
- Flow rate
- Kinematic viscosity
- Pipe dimensions
- Fluid density
The pressure loss in straight pipes (
∆
P(line)) can be calculated as follows:
Δp ≈ 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
= Kinematic viscosity [mm²/s]
D
= Density [kg/dm³]
HFD-R ≈ 1.14 kg/dm³
HFD-U ≈ 0.92 kg/dm³
Additional threaded connections and pipe bends increase the pressure
differential and must be taken into account.
Keep the height difference between the pump and the oil level in the tank as
small as possible.
Avoid constrictions in the connected hoses. They compromise output and
increase the risk of cavitation.
VMU 1 ATEX II 2G IIC T4
en(us)
Page 31 / 68
BeWa VMU_1_ATEX-II2GIICT4_10000649233 en-us 2017-03-07.doc
2017-03-07