Series SCK, Size 25-25-100
Page 7
9220-003-en
Revision 14
TM 10272
Edition 01/2021
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 identification on the pump relates to the
pump section
including mechanical seal
.
For classification in a certain temperature
class, the data in the operating manuals of
the mechanical seal manufacturer and of the
pump manufacturer are to be matched for
each individual application. A separate dec-
laration of conformity must be provided for
the shaft coupling and motor and for other
attachments as well as corresponding identi-
fication.
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 remove the "potentially explosive"
identification from the pump component and, if
necessary, from other attachments or make the
marking obscure.
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
identification (e.g. T4 ... T3 for gas or for dust D135 °
C ... T200 ° C).The temperature class must be deter-
mined 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 mechanical seal.
We recommend you to only perform a check
of the direction of rotation with the coupling
disengaged or with a rotating field instru-
ment. See also
Section 6.1.3
.
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 run-
ning). This results in serious damage to
the pump and additional risks to the envi-
ronment can arise.
Dry-running cannot only occur with an insuf-
ficiently 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 normal operating mode the highest
temperatures are to be expected at the
contact point shaft seal/shaft (only with oil
bath lubrication), on the inner races of the
ball
bearings
and
at
high
medium
temperatures on the surface of the pump
housing.
We would like to point out that, under extreme operat-
ing (medium temperature > 160°C) and ambient con-
ditions (ambient temperature > 30 °C), temperatures
of over 130°C may arise on the surface of the pump
housing.
In the case of liquids >40 °C the surface temperature
of the pump housing is generally lower than the tem-
perature of the liquid as the plastic lining has an insu-
lating effect.
If the pump is heated (e.g. heating jacket), it
must be ensured that the temperature clas-
ses prescribed in the annex are observed.
The non heated pump surface must have free contact
with the environment.
During operation of the pump it must be ensured that
excessive deposits of dust are prevented (regular
cleaning) in order to prevent the pump surface from
heating to above the admissible temperature.
The plant customer must ensure that the pre-
scribed operating temperature is observed. The
maximum admissible temperature of the liquid
medium at the pump inlet depends on the temper-
ature class and the selected lining material re-
quired in each case.
