2 operating limits, 1 abrasive media, 2 min./max. flow rate – Richter MNK Series User Manual

Page 14: 3 shutdown, 4 restarting, Operating limits, Abrasive media, Min./max. flow rate, Shutdown, Restarting

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Series MNK

Page 14

9230-050-en

Revision 11

TM 7903

Edition 07/2010

The pump must be completely filled with liquid.
The maximum admissible flow rate must not
be exceeded.

Otherwise the plain bearings can run dry in
both cases.

Switch the motor on.
Set the desired flow by opening the discharge
valve.

When the motor is running but the pump is not
conveying, this means that the magnetic drive
has stopped.

Switch motor off immediately in order to prevent
overheating of the magnet assemblies.

Then proceeded as follows:

Close discharge valve down to the position
"minimum flow rate".
Start motor again.

If the magnetic drive stops again, look for the cause.

6.2 Operating limits

The operating limits of the pump/unit in terms
of pressure, temperature, power and speed
are entered in the data sheet and it is

imperative to observe them!

6.2.1 Abrasive media

If liquids with abrasive constituents are
conveyed, increased wear at the pump is to
be expected. The inspection intervals should

be reduced compared with the usual times.

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
"minimum 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 inert

gas (e.g. nitrogen) to prevent an explosive
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.
If the pump is returned to the manufacturer's, clean
the pump very thoroughly.
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 a
short time, can 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) may
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.
Axial thrust too great.

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