Richter MNK Series - Manual (Page 7)

Series MNK, MNK-B, external flushing Page 7
9230-060-en Revision 02
TM 6778 Edition 05/2007
5.4 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 in-
duced 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 an adequate flow
of flushing medium :
The process medium penetrates the can chamber
and jeopardises functionability.
The flushing medium is stopped before the
pump is evacuated :
The process medium penetrates the can chamber
and jeopardises functionability.
The suction valve is closed when the pump is
at a standstill :
The flushing medium can no longer flow into the
pump if the back pressure is too high.
The suction line is not or not completely
open :
Pump cavitates - material damage to the pump
and plain bearings
Pump does not attain the necessary delivery head
or flow rate.
Pump is destroyed due to overheating.
Overrun of the admissible gas content:
The flow may stop.
Switch pump and vent off for renewed convey-
ance.
Make sure that the gas content is not exceeded,
as described in the intended use.
Regulation of pump with the suction valve :
Cavitation. The flow is only to be regulated on the
discharge side.
Discharge valve completely closed:
Pump is destroyed due to overheating.
Excessive shaft deflection with consequences
for the plain bearings.
Excessive load on the plain bearings with con-
sequences for their service life.
Discharge valve completely open :
Pump cavitates particularly severely with the dis-
charge line emptied.
Motor and magnetic drive are overloaded.
Risk of pressure surges.
Suction valve and discharge valve closed :
Destruction due to rapid overheating and sharp
rise in pressure.
6 Maintenance
6.1 Notes on dismantling
All repair and maintenance work is to be performed by
qualified staff using appropriate tools and original
spare parts.
Is the necessary documentation available?
Has the pump been taken out of operation, evacuated
and flushed correctly?
See also Section 5.3.
If the flushing medium fails, the process liquid may
enter the flushing medium feed line. Protective cloth-
ing in accordance with the regulations must therefore
be worn.
The pump is dismantled and assembled in accor-
dance with the operating manual. Care must be taken
to ensure that the flushing connection is in the correct
position.
6.2 Dismantling
Remove flushing valve or any elbow provided
720/1.
Undo lock nut 920/7.
Unscrew transition pipe 721/1.
Remove support 732.
Remove O-ring 412/2 using a feeler gauge
(0.3 mm).