Richter MNK Series - Manual (Page 3)

Series MNK, MNK-B, external flushing Page 3
9230-060-en Revision 02
TM 6778 Edition 05/2007
Field of application:
Flushing of the plain bearings with a solids-free exter-
nal medium which is compatible with the process liq-
uid.
With this facility the magnetic drive pump is suitable
for all types of solids for which mechanical seal pumps
are also used. Grain size <2 mm.
In addition to the intended use mentioned in
the installation and operating manuals
MNK long life grease lubrication 9230-050-en
MNK oil bath lubrication 9230-051-en
MNK-B close-coupled design 9230-055-en
the following applies to external flushing:
The observance of the specified physical limits is im-
portant for perfect functioning and safe operation,
especially with regard to explosion protection to pre-
vent potential sources of ignition:
Observance of the minimum flushing flow. The
pump may only be put into operation when the
flushing medium flow is available! See table in
Section 5.1.3.
Risk:
Lack of lubrication of the plain bearings.
Result: Inadmissible rise in temperature
Observance of the minimum flushing pressure.
Risk:
Lack of lubrication of the plain bearings.
Result: Inadmissible rise in temperature
Max. flushing medium temperature must not be
exceeded.
Risk:
Lack of lubrication of the plain bearings.
Result: Inadmissible rise in temperature
When the pump is switched off and evacuated, the
flushing medium flow may only be switched off
when the pump is completely emptied.
Risk:
Lack of lubrication of the plain bearings.
Result: Inadmissible rise in temperature
The suction valve must not be closed when pump
at a standstill in order to prevent the medium enter-
ing the can chamber.
Risk:
Lack of lubrication of the plain bearings.
Result: Inadmissible rise in temperature
Incompatibility of the flushing medium and process
liquid can cause inadmissible modes of operation,
e.g. inadmissible temperature rise due to exother-
mal reaction, hardening or agglomeration of the
medium, inadmissible gas formation etc.
The entire outer surface must have free contact
with the surroundings.
When flushing operations are under way, it must
be ensured that an excessive sedimentation of
dust is prevented (poss. regular cleaning) in order
to prevent the surface heating to above the admis-
sible temperature.
Flushing may only take place when the pump is
filled with the medium. During evacuation the for-
mation of a potentially explosive atmosphere must
be prevented with the use of inert gas.
The flushing unit must be grounded to be conduc-
tive to ensure safe operation. The conductive
grounding of the flushing unit can most easily be
achieved by using tooth lock washers at a
grounded flange.
Electric peripherals, e.g. pressure, temperature,
flow sensors etc., must comply with the valid safety
requirements and explosion protection regulations.
2 Safety, transport, storage and disposal
The relevant chapters in the adjacent installation and
operating manuals apply to safety, transport, storage
and disposal. This supplementary operating manual is only valid in
conjunction with the following installation and operat-
ing manuals:
MNK
long life grease lubrication 9230-050-en
MNK oil bath lubrication 9230-051-en
MNK-B close-coupled design 9230-055-en
3 Product description
The housing dimensions, power ratings and technical
requirements of the pump series MNK comply with
ISO 2858 / DIN EN 22858 / ISO 15783 / DIN ISO
5199. The technical requirements of VDMA 24279 are
satisfied.
The sectional drawing shows the external flushing
unit. See Section 7.1.
The flushing medium flows into the can chamber and
from there through the plain bearings into the pump
housing. The transition pipe 721 of the flushing connection is
screwed into the plain bearing pedestal and sealed
with an O-ring 412/2.
If the external flushing unit is retrofitted, the housing
100 and bearing pedestal 330 must be adapted.
In contrast to a normal plain bearing pedestal, the
plain bearing pedestal for the flushing connection
has no axial openings through which the process
medium could enter the can chamber.