Series RMA-B
close-coupled design
Page
8
9450-055-en
Revision 01
TM 9886
Edition 11/2018
Dry-running cannot only occur with an
insufficiently 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 evaporation in the interior).
2.6.7 Temperature limits
In the normal operating condition the highest
temperatures are to be expected on the
surface of the pump housing.
In the case of liquids >40 °C (>104 °F) the surface
temperature of the pump housing is generally lower
than the temperature of the liquid as the plastic lining
has an insulating effect.
If the pump is heated (e.g. heating jacket), it
must be ensured that the temperature
classes prescribed in the annex are
observed.
The non heated pump surface must have free contact
with the environment.
When operating the pump, make sure that
an excessive deposit of dust is avoided
(possibly regular cleaning). This prevents the
pump surface from heating to above the admissible
temperature.
The plant customer must ensure that the
prescribed operating temperature is observed.
The maximum admissible temperature of the
liquid medium at the pump inlet depends on the
temperature class and the selected lining material
required in each case.
The principle always applies that no inadmissible
temperatures may be introduced into the motor and
that the specifications of the motor manufacturer as
well as VDMA/TVEI 24263 are to be observed.
The temperature limit values of the liquid medium
given in
Table 2
are only applicable if motors are used
where the motor manufacturer permits at least the
following surface temperatures for the motor flange
and shaft:
Table 1
Temperature
class
Motor flange
Motor shaft
T6
70 °C(158 °F)
70 °C(158 °F)
T5
70 °C(158 °F)
80 °C(176 °F)
T4
75 °C(167 °F)
85 °C(185 °F)
T3
75 °C(176 °F)
85 °C(212 °F)
T2
75 °C(176 °F)
85 °C(212 °F)
T1
75 °C(176 °F)
85 °C(212 °F)
Observe the figures of the motor manufacturers and
VDMA/ZVEI 24263 on inadmissible ambient
temperatures. If these values are missing, max. 40° C
(104 °F) is to be assumed.
Table 2
below indicates the admissible medium
temperature, depending on the pump design, as a
function of the temperature class in accordance with
EN 13463-1.
Table 2
Temperature class acc.
to EN 13463-1
Limit value of the
temperature of the liquid
PFA
T6
85 °C (185 °F)
75 °C
1)
(167 °F)
T5
100 °C (212 °F)
90 °C
1)
(194 °F)
T4
135 °C (275 °F)
125 °C (257 °F)
T3
200 °C (392 °F)
150 °C (302 °F)
T2
300 °C (572 °F)
150 °C (302 °F)
T1
450 °C (842 °F)
150 °C (302 °F)
1) The limit values specified for the temperature of the medium at the
pump inlet are determined for the most unfavourable case (high
speed, low flow, low heat capacity of the medium, ....). Under
favourable operating conditions the limit values specified may be
increased by up to 5 K after consultation with the manufacturer.
In the case of motors with the ignition protection class
"increased safety", only low surface temperatures are
generally admissible on the motor shaft and on the
motor flange.
In such cases, the max. admissible medium
temperature lies 20 K above the permitted surface
temperature at the interfaces to the motor.
e.g.: max. motor shaft temperature: 60 °C (140 °F)
max. motor flange temperature: 65 °C (149 °F)
This results in an admissible medium temperature at
the pump of von
80 °C (60 °C + 20 K),
.176 °F (140 °F
+ 20 K).
If values on the admissible ambient temperature are
missing, max. 40 °C is always to be assumed.
2.6.8 Maintenance
To achieve safe and reliable operation, it
must be ensured in inspections at regular
intervals that the unit is properly serviced
and kept in technically perfect order.
In regard to media containing solids, the maintenance
intervals must be set by the operator in accordance
with the conditions of operation.
If auxiliary systems (e.g. cooling, heating) are
installed, check to see whether monitoring facilities
are required to ensure their function.
2.6.9 Electric peripheral equipment
Electric peripheral equipment, e.g. pressure,
temperature and flow sensors etc. must
comply with the prevailing safety requirements
and explosion protection provisions.
Regular checks of the motor bearings in accordance
with the operating manual of the motor manufacturer.
Observe ATEX notes.
