Technical Data; Operating Conditions - Grundfos CR 95 Installation And Operating Instructions Manual

9. Technical data

9.1 Operating conditions

9.1.1 Ambient temperature and altitude
See the instructions for the motor which are supplied
with the pump.
9.1.2 Maximum system pressure and liquid
temperature
The maximum permissible system pressure and
liquid temperature are stated on the nameplate
which is placed on the pump. For identification of the
nameplate data, see section
9.1.3 Maximum permissible operating pressure
and liquid temperature for the shaft seal
The operating range of a shaft seal depends on the
operating pressure, the liquid temperature and the
type of shaft seal.
The selection charts show which shaft seals are
suitable at a given temperature and a given
pressure.
See figs 26 and 27. The charts apply to clean water.
Shaft seals for ∅22 shaft ends: CR, CRN with
motors up to and including 55 kW
p [bar]
50
40
HQQE/V
30
20
HQQE/V
10
0
-40 -20 0 20 40 60
Fig. 26 Maximum permissible operating
pressure and liquid temperature for
pumps with ∅22 shaft seal ( ≤ 55 kW)
Shaft seals for ∅28 (75-110 kW) and ∅36 (132-200
kW) shaft ends
p [bar]
50
40
HQQE/V
30
20
HQQE/V
HQBE/V
10
0
-40 -20 0 20 40
Fig. 27 Maximum permissible operating
pressure and liquid temperature for
pumps with ∅28 shaft seal (75-110 kW)
and ∅36 shaft seal (132-200 kW)
22
5.1.1 Nameplate.
HQQE
t [°C]
80 100 120 140
HQQE
HQBE
t [°C]
60 80 100 120 140
9.1.4 Minimum inlet pressure
Hf
H
Pb
Fig. 28 Schematic view of open system with a
CR pump
Calculate the maximum suction lift "H" in m head as
follows:
H = Pb x 10.2 - NPSH - Hf - Hv
Pb = Barometric pressure in bar.
Barometric pressure can be set to 1 bar.
In closed systems, Pb indicates the system
pressure in bar.
NPSH = Net Positive Suction Head in m head, to be
read from the NPSH curve on page
the highest flow the pump will be delivering.
Hf = Friction loss in the inlet pipe in m head at
the highest flow the pump will be delivering.
Hv = Vapour pressure in m head. See
page 28.
tm = Liquid temperature.
If the calculated "H" is positive, the pump can
operate at a suction lift of maximum "H" m head.
If the calculated "H" is negative, an inlet pressure of
minimum "H" m head is required. There must be a
pressure equal to the calculated "H" during
operation.
NPSH
Hv
24 at
Fig. E on