Richter MNK Series, Инструкция по установке и эксплуатации

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Series MNK pedestal group 4
Page
7
9230-003-en Revision 19
TM 10458 Edition 06/2022
2.6.2 Special operating conditions
In the standard version the plain bearings
are lubricated and cooled by the internal
flushing circuit.
Owing to properties of the medium (e.g. sticking due to
inadmissible solids entrainment, clogging, gas entrain-
ment etc.) the cooling flow can be interrupted and, as a
result, an inadmissible temperature rise may occur.
Provide appropriate monitoring facilities. See
Section
5.6 .
For safe pump operation, we recommend a flow rate of
0.3 to 1.1 Qopt. If the pump is operated outside this
range, it must be ensured that the max. admissible flow
rate according to the pump characteristic curve is not
exceeded and that the max. admissible operating
temperature according to
Section 2.6.7 is observed.
If the flow rate is too high, the differential pressure
upstream and downstream of the plain bearings could
fall so much that a lack of lubrication or dry-running may
occur.
If the flow rate is too low, the medium may heat up so
much owing to the fluid friction that the max. admissible
surface temperature of the relevant temperature class
is exceeded.
Overloading, overheating, non-observance of the de-
sign data or the incorrect selection of the magnetic
drive can lead to the decoupling of the inner and outer
magnet assemblies. As a result, eddy currents may be
induced on the inner and outer magnet assemblies and
an inadmissible temperature rise may occur. Provide
appropriate monitoring facilities. See
Section 5.6 .
The plant NPSH value (NPSHA) should be minimum
0.5 m higher than the NPSH value of the pump
(NPSHR) to prevent a lack of lubrication or dry-running
of the plain bearings.
2.6.3 Chargeable liquids
For operation with chargeable liquids with
a conductivity < 10
-8
S/m inert gas must be
used for flushing during evacuation if the
lining of the pump is non-conductive. See
Section 6.3 .
2.6.4 Identification
The ex identification on the pump relates
to the pump section. A separate declara-
tion of conformity must be provided for the
shaft coupling and motor and for other at-
tachments as well as corresponding iden-
tification.
Example of the identification of the pump section:
For assembling the pump with components which are
not explosion-protected (e.g. motor, shaft coupling), it
is recommended to mask or remove the "potentially
explosive" identification from the pump component
and, if necessary, from other accessories.
In this case the declaration of conformity applies with-
out ATEX identification.
For surface temperatures that mainly depend on the
operating conditions of the pump, DIN EN ISO 80079-
36 Chapter 11.2 f) and g) state that no temperature
class or temperature may be specified. In this case, the
identification must include temperature range identifi-
cation (e.g. T4 ... T3 for gas or for dust D135 ° C ...
T200 ° C).
The temperature class must be determined by the op-
erator in accordance with Section 2.6.7 “Temperature
Limits”.
2.6.5 Check of the direction of rotation
If there is also a risk of explosion during the installation
phase, the check of the direction of rotation must under
no circumstances be conducted by briefly switching on
the unfilled pump in order to prevent an inadmissible
rise in temperature at the plain bearings.
We recommend you to only perform a check of the
direction of rotation with the coupling disengaged or
with a rotating field instrument. See also
Section 6.1.2.
2.6.6 Mode of operation of the pump
The pump may only be started with the suction side
shut-off element fully opened and the discharge side
shut-off element slightly opened. Start-up against a
closed check valve is also possible. The discharge side
shut-off element is to be regulated to the operating
design point directly after run-up.
See also
Section 5.4.1.
Operation with closed shut-off elements in the
suction and/or discharge lines is not permitted!
There is a risk that even after a short time
high surface temperatures on the pump
housing may occur owing to rapid heating
of the liquid in the pump interior.
A rapid rise in the pressure inside the
pump involves the risk of overloading to
the point of bursting.
The pump must not be in operation in
the unfilled or partially filled state (dry
running). This results in serious dam-
age to the pump and additional risks
to the environment can arise.
Dry-running cannot only occur with an in-
sufficiently filled interior but also in the
event of high gas contents in the liquid
medium.
Operation of the pump outside the admissible operating
range may also lead to dry-running (e.g. due to evapo-
ration in the interior).