Dutypoint VT Booster Set, Руководство по эксплуатации и обслуживанию, Страница: 34 / 123

English (GB)
G
5
5.2 Liquid temperature
The table on page 15 states the relationship between liquid
temperature range and maximum permissible operating pressure.
5.3 Maximum permissible operating pressure and
liquid temperature for the shaft seal
CR, CRI, CRN 1s to 20 and CR, CRN 32 to 150
Fig. 3
Maximum permissible operating pressure and liquid
temperature
CRI and CRN pumps using a type H shaft seal with EPDM rubber
parts, HxxE, can be cleaned in place (CIP) with liquids up to
150 °C for maximum 15 minutes.
CR, CRI, CRN pumps are not suitable for the pumping of liquids
above 120 °C for long periods.
5.4 Minimum inlet pressure
Fig. 4
Schematic view of open system with a CR pump
The maximum suction lift "H" in metres head can be calculated as
follows:
H = p
b
x 10.2 - NPSH - H
f
- H
v
- H
s
p
b
= Barometric pressure in bar.
(Barometric pressure can be set to 1 bar.)
In closed systems, p
b
indicates the system pressure in
bar.
NPSH = Net Positive Suction Head in metres head (to be read
from the NPSH curve on page 13 at the highest flow the
pump will be delivering).
H
f
= Friction loss in suction pipe in metres head at the
highest flow the pump will be delivering.
H
v
= Vapour pressure in metres head, see fig. E on page 18 .
t
m
= liquid temperature.
H
s
= Safety margin = minimum 0.5 metres head.
If the calculated "H" is positive, the pump can operate at a suction
lift of maximum "H" metres head.
If the calculated "H" is negative, an inlet pressure of minimum "H"
metres head is required. There must be a pressure equal to the
calculated "H" during operation.
Example
p
b
= 1 bar.
Pump type: CR 15, 50 Hz.
Flow rate: 15 m
3
/h.
NPSH (from page 13 ): 1.1 metres head.
H
f
= 3.0 metres head.
Liquid temperature: +60 °C.
H
v
(from fig. E, page 18 ): 2.1 metres head.
H = p
b
x 10.2 - NPSH - H
f
- H
v
- H
s
[metres head].
H = 1 x 10.2 - 1.1 - 3.0 - 2.1 - 0.5 = 3.5 metres head.
This means that the pump can operate at a suction lift of
maximum 3.5 metres head.
Pressure calculated in bar: 3.5 x 0.0981 = 0.343 bar.
Pressure calculated in kPa: 3.5 x 9.81 = 34.3 kPa.
Note
The maximum permissible operating pressure
and liquid temperature ranges apply to the pump
only.
Note
The diagram below applies to clean water and
water containing anti-freeze liquids.
TM
03 88
53 490
7
Standard shaft seal
Motor
[kW]
Max. temperature range
[°C]
HQQE 0.37 - 45 -40 °C to +120 °C
HBQE 55 - 75 0 °C to +120 °C
HQQV 0.37 - 45 -20 °C to +90 °C
HBQV 55 - 75 0 °C to +90 °C
Note
The pumping of liquids above +120 °C may result
in periodical noise and reduced pump life.
-60 -40 -20 0 20 40 60 80 100 120 140
0
5
10
15
20
25
30
35
p [bar]
HQQE/V
HBQE/V
H
Q
Q
E H
Q
Q
E H
B
Q
E H
Q
Q
V H
Q
Q
E
t [°C]
TM0
2 0
118
38
00
Hv
H
NPSH
Pb
Hf