2 special operating conditions, 3 chargeable liquids, 4 identification – Richter RMA Series User Manual

Page 7: 5 check of the direction of rotation, 6 mode of operation of the pump, Special operating conditions, Chargeable liquids, Identification, Check of the direction of rotation, Mode of operation of the pump

Series RMA

Page 7

9475-050-en

Revision 12

TM 7978

Edition 08/2010

2.6.2 Special operating conditions

In the standard design the can chamber and
the plain bearings are cooled and lubricated
by a flushing flow.

Owing to properties of the medium (e.g. sticking due
to inadmissible solids entrainment, clogging, gas
entrainment etc.) the cooling flow can be interrupted
and, as a result, an inadmissible temperature rise may
occur. Provide appropriate monitoring facilities. See
also Section 5.6.
For safe pump operation, we recommend a flow rate
of 0.3 to 1.1 Q

opt

. 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
design 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.
The situation is to be remedied by providing
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 drain. See also Section 6.3.

2.6.4 Identification

The identification on the pump relates to the
pump section. A separate declaration of
conformity must be provided for the shaft

coupling and motor and for other attachments as well
as corresponding identification.
Example of the identification of the pump section:

II2GD IIC TX X.

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
without ATEX identification.
In this case the declaration of conformity applies
without ATEX identification.
At surface temperatures which depend primarily on
operating conditions, DIN EN 13463-1 Chapter 9.3
allows no temperature class or temperature to be
indicated.
The temperature class must be determined by the
operator 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.