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4.8.3 Determination example
Given:
Q = 0.69 l / min (1.46 pts / min) working
viscosity v = 300 mm
2
/s differential pressure Δp = 50 bar
(e.g., system pressure 90 bar, back pressure 40 bar)
1 Preselection of the nozzle index
-see diagram in Fig. 12
Consult the diagram to obtain the intersection between the
desired flow rate (0.69 l/min) and working viscosity (300
mm
2
/s).
The closest curve defines the nozzle index (105). The nominal
flow rate for this nozzle with loss of nominal pressure (Δp = 20
bar) is derived from the intersection of the nozzle characteristic
curve (105) and the working viscosity (300 mm
2
/s).
In this example, it is 0.73 l/min. (1.54 pts / min).
2 Determination of the correction
-see diagram in Fig. 13
Factor and calculation of the actual flow rate.
The correction factors for a viscosity of 300 mm
2
/s can be
obtained from the range marked in blue.
Find the intersection of the nozzle index 105 with the lower
border of the range marked in blue, which depicts the
differential pressure of 50 bar. The correction factor results
from extracting the value on the vertical axis which corresponds
to the intersection.
The result is 0.93.
3 Calculation of the resulting oil volumetric flow
Multiply the result determined under 1 times the correction
factor calculated under 2.
> 0.73 l / min. × 0.93 = 0.68 l / min
(1.44 pts / min)
