6 Commissioning/Start-up/Shutdown
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CHTRa
6.6.3 Fluid handled
6.6.3.1 Flow rate
The data refer to water and water-like fluids. Longer operating periods with these
fluids and at the flow rates indicated will not cause an additional increase in the
temperatures at the pump surface. However, if the physical properties of the fluids
handled are different from water, the calculation formula below must be used to
check if an additional heat build-up may lead to a dangerous temperature increase at
the pump surface.
Flow rate
Unless specified otherwise in the characteristic curves or data sheets, the following
applies:
Q
max.
2)
: See characteristic curves
Q
min.
3)
= 0.3 x Q
opt.
4)
T
o
= T
f
+ ΔT
ΔT =
g
x
H
c
x
η
x
(1 - η)
Fig. 31:
Calculation formula
Table 17:
Key
Symbol
Description
Unit
c
Specific heat capacity
J/kg K
g
Gravitational constant
m/s
2
H
Head
m
T
f
Temperature of the fluid handled
°C
T
o
Temperature at the casing surface
°C
η
Pump efficiency at duty point
-
ΔT
Temperature difference
°C
6.6.3.2 Density of the fluid handled
The pump input power changes in proportion to the density of the fluid handled.
CAUTION
Impermissibly high density of the fluid handled
Motor overload!
▷
Observe the information about fluid density in the data sheet.
▷
Make sure the motor has sufficient power reserves.
6.6.3.3 Abrasive fluids
Do not exceed the maximum permissible solids content specified in the data sheet.
When the pump handles fluids containing abrasive substances, increased wear of the
hydraulic system and shaft seal are to be expected. In this case, reduce the commonly
recommended inspection intervals.
2)
Maximum permissible flow rate
3)
Minimum permissible flow rate
4)
Best efficiency point
