Series MNKA bearing pedestal assembly 4
Page 8
9250-003-en
Revision 01
TM 10458
Published 06/2022
Operating the pump outside the permissible
operating range can also lead to dry running
(e.g. due to evaporation in the interior).
2.6.7 Temperature limits
In normal operating condition, the highest temper-
atures are to be expected at the shaft seal / shaft
contact point, on the inner rings of the
rolling bearings and at high media temperatures
on the surface of the pump housing.
We draw your attention to the fact
that the surface temperature of the
pump housing is only slightly lower
than the medium temperature.
If the pump is heated (e.g. heating jacket), it must
be ensured that the temperature classes specified
in the plant are observed.
The non-heated pump surface must have clear
contact with the environment.
When operating the pump, ensure that
excessive dust deposits are prevented
(clean regularly if necessary). This
prevents the pump surface from heat-
ing up above the permissible temper-
ature.
Depending on the pump version,
Table 1
below
shows the permissible media temperature taking
into account the applicable temperature class as
per DIN EN ISO 80079-36. (Also see the appen-
dix to the operating instructions: Application limits
9230-00-3046)
Table 1
Temperature class
as per DIN EN ISO
80079-36
Limit value of the pumped
liquid temperature
Lining material
PFA/PTFE
Can material
2)
CFK-F
T4
(135 °C)
125 °C
1)
T3
(200 °C)
180 °C
3)
1) Permanently greased rolling bearings: no restrictions.
T4 is only valid for operation up to 1750 min
-1
.
2) The can material is listed in the data sheet.
3) If the temperature of the pumped liquid exceeds 180 °C, the
ATEX approval becomes permanently invalid. The ATEX plate
must be removed immediately by the operator. A new ATEX
approval can only be issued by a judge. For this purpose, the
pump can be sent in for inspection.
The system operator must ensure that the
specified working temperature is maintained.
The maximum permissible temperature of the
pumped liquid at the pump inlet depends on
the respective required temperature class and
the selected lining materials.
2.6.8 Maintenance
For safe and reliable operation, en-
sure that the unit is properly main-
tained and kept in technically perfect
condition by means of regular inspec-
tion intervals.
Example: Rolling bearing function. Operating
mode and operating conditions essentially
determine the bearings’ actual achievable service
life.
Regular checks of the bearing pedestal area can
prevent overtemperatures caused by hot-running
rolling bearings, start-up of the drive rotor at the
lantern or even defective bearing seals. See
section 7.2
.
In the case of media containing solids, the mainte-
nance intervals must be determined by the opera-
tor in relation to the operating conditions.
If auxiliary systems (e.g. external flushing, cooling,
heating) are installed, check if monitoring devices
are necessary to ensure their function.
2.6.9 Electrically operated peripheral
devices
Electrically
operated
peripheral
devices,
such
as
pressure,
temperature, and flow sensors, must
comply with the applicable safety
requirements and explosion protection
regulations.
