OPERATING INSTRUCTIONS
26
17.2.1.1.1 Diagrams 1
Example: V 55
In case of an inlet pressure of 130 mbar is the fresh
water requirement at continued cooling V
FD
= 0,37
m
3
/h,
the fresh water requirement at circulation cooling
and a temperature difference Dt = 5°C V
FU
=
0,15m
3
/h
17.3
Cavitation: Causes and how to
avoid them
CAUTION
In case that the suction pipe I
s
is provided with
a shut-off device (slide or similar), and the
pump should be kept running, when this shut-
off device is closed, cavitation will be caused.
Consequently parts of the pump will be
destroyed, in case the pump is running a
longer period.
In case mainly steam shall be delivered, which
condenses during compression, also cavitation
is caused in the pump.
In order to avoid cavitation with its
consequences, a small quantity of gas will be
added at suction side, which cannot
condensate at compression:
This can be effected through:
a ventilation device h,
through a pipe with jet nozzle I
G
elevated by
300 mm or
through a connecting pipe (with nozzle) to the
liquid separator a.
The use of a gas ejector also avoids cavitation
(see illustr. 5).
17.4
Contaminated operating liquid,
deposits
In case that with the operation liquid or with the
delivered gas fine-grained dirt gets into the
pump, it can be rinsed out through the
connections U
se
during the operation from time
to time, in order to avoid wear-out.
In case that a big quantity of dirt will be
produced, the discharge should be made
repeatedly. When the pump stands still then
the pump will be emptied. Therefore this pipe
has to be closed before switching it off or the
pump has to be refilled up to the middle of the
shaft before recommissioning it.
When operating the pump with water, the
hardness of the water has to be strictly
observed, as very hard water leads to furring in
the pump. In such cases the required water
has to be treated (softened) before using it as
ring liquid or the pump has to be opened from
time to time and the deposits have to be
removed. As the impurities (rust, dirt etc.) are
gathered in the liquid separator, it has to be
cleaned as well in corresponding intervals.
18
Maintenance
Due to their simple and robust construction the
vacuum pumps in closed coupled version need
not very much maintenance. Any maintenance
work needed is resulting from the operating
conditions. In case the operating liquid should
be very hard water or a medium charged with
3
(m /h)
Durchlaufk¤hlung
60 Hz
50 Hz
(CFM)
FU
V
circulation cooling
(CFM)
FD
V
1.0
0.8
0.6
0.4
0.2
continuous cooling
0.80.70.60.50.40.30.20.1
inlet pressure (INCH HG)A
20
15
10
532
26
900
1
400300200150
100
60
40
33
Frischwasserbedarf bei
1b
1a
Frischwasserbedarf bei
offener Umlaufk¤hlung [m3/h]
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
Ansaugdruck [mbar]
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
600
V
FD
2
C
5
C
1
0
C
2
0
C
V 430
V 330
V 255
V 95-155
V 55
V 6/30
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