Series MNK pedestal group 4
Page
15
9230-003-en
Revision 19
TM 10458
Edition 06/2022
6.2.2 Min./max. flow rate
The operating range generally recommended lies at 0.3
Q
opt
to 1.1 Q
opt
. Consult the manufacturer for operation
outside this range and observe
Section 2.6.2
.
6.3 Shutdown
♦
Close discharge valve down to the position "mini-
mum flow rate"
♦
Switch motor off.
♦
Close discharge valve completely.
Only close the suction line if the pump is
to be evacuated or dismantled.
For all work on the machine, make sure
that the motor cannot be inadvertently
switched on.
If the pump is to be evacuated or flushed, observe the
local regulations.
If the pump has been operated with a
chargeable liquid, it must be filled with in-
ert gas (e.g. nitrogen) to prevent an explo-
sive atmosphere.
It is recommended to wait one hour before the pump is
dismantled from the plant to permit static peak charges
to be eliminated.
These measures are not necessary with pumps with a
conductive plastic lining.
These measures are not necessary with pumps with a
conductive plastic lining.
See also
Section 3.1
.
6.4 Restarting
When the pump is restarted, it must be ensured that all
the relative steps as described in
Section 6.1
are
repeated, depending on the progress of the shutdown
operation.
6.5 Improper operations and their
consequences (examples)
Inadmissible modes of operation, even for
brief periods, may result in serious
damage to the unit.
In connection with explosion protection, potential
sources of ignition (overheating, electrostatic and
induced charges, mechanical and electric sparks) can
result from these inadmissible modes of operation; their
occurrence can only be prevented by adhering to the
intended use.
Pump is started up without medium:
♦
The plain bearings in the pump may be destroyed.
♦
Other pump components may be destroyed due to
overheating.
Operation with magnetic drive stopped:
♦
If no heat is dissipated, damage to the inner and
drive magnet assemblies may occur.
Suction line not opened or not opened fully:
♦
Pump is cavitating
–
material damage to pump and
plain bearings
♦
Pump does not attain the required delivery head or
flow rate.
♦
Pump may be destroyed due to overheating.
Discharge valve closed too much :
♦
Pump may be destroyed due to overheating.
♦
Pump can cavitate. Particularly severe with an
empty discharge line.
Discharge valve opened too much :
♦
Pump can cavitate. Particularly severe with an
empty discharge line.
♦
Risk of pressure surge.
♦
Possible damage to the plain bearings.
♦
Magnetic drive may stop.
♦
Motor may be overloaded.
Suction valve and discharge valve closed :
♦
Destruction due to rapid overheating and sharp rise
in pressure.
Control of the pump with the suction valve :
♦
Cavitation
–
the volume may only be regulated on
the discharge side.
Overrun of the admissible gas content:
♦
The flow may stop.
♦
Switch pump and vent off for renewed conveyance.
♦
Make sure that the gas content is not exceeded, as
described in the intended use.
