ELK
9.7.2 Table of operational viscosity for VG oil
10 °C
20 °C
30 °C
40 °C
50 °C
60 °C
70 °C
80 °C
90 °C
VG 46
264,45
131,96
73,58
46,00
29,13
20,04
14,43
10,78
8,32
VG 68
444,77
210,85
112,61
68,00
41,63
27,86
19,58
14,32
10,84
VG 220
2.120,17
861,60
404,31
220,00
121,71
74,99
49,00
33,61
24,01
VG 320
3.489,92
1.350,22
607,96
320,00
171,40
102,85
65,66
44,12
30,94
Viscosity given in cst (mm
2
/s)
9.7.3 Calculating the pressure loss
Valid for smooth straight piping per meter at laminar current.
Definitions
Example: oil VG 46
ʋ
Viscosity in cst
ʋ
97,35 cst
ρ
spec. gravity in kg/dm
3
ρ
0,8817 kg/dm³
DN
tube diameter in mm
DN
20 mm
V
flow in m/s
V
3,18 m/s (60 l/min for tube DN 20)
PV
pressure loss in bar
NOTICE
Pressure loss increases significantly for bends and fittings.
It might be necessary in some cases to determine the final shape of the suction line on
site under specific conditions.
Please do not hesitate to contact us for help to calculate the pressure loss of the suction line for you specific application.
NOTICE
To avoid damage of the cooling system, make sure that the maximum pump pressure is
not exceeded. High pressure may occur if the system is shut off or throttled at the pres-
sure side.
18
Bühler Technologies GmbH
BE350034 ◦ 08/2022
Summary of Contents for 35ELK10040
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