Richter MPB 25-25-115 - Manual (Page 7)

Series MPB, close-coupled design Page 7
9240-050-en Revision 05
TM 7345 Edition 10/2008
This designation means that the pump may be used in
atmospheres which may ignite above the temperature
class T4, i.e. >135°C.
The temperature class with the highest ignition
temperature is always decisive for the entire unit, e.g.
pump, coupling, motor.
Example 1: Pump T3, motor T4
Example 2: Pump T4, motor T3
In both cases the unit may only be used in
atmospheres which may ignite above the temperature
class T3, i.e. >200°C.
The general rule is that the admissible limit value of
the medium temperature in accordance with Section
2.6.7 must be taken into account.
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 filled pump and
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 damage to the pump and additional
risks to the environment can arise.
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.
We would like to point out that, under extreme
operating (medium temperature > 160°C) and
ambient conditions (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
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 not 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
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 following always applies: No inadmissible
temperatures may be introduced into the motor and
the specifications of the motor manufacturer must be
observed.
The temperature limits of the fluid given in Table 2
only apply when motors are used where the motor
manufacturer permits at least the following
temperatures for the motor flange and motor shaft:
Table 1
Temperature
class
Motor flange Motor shaft
T6 70 °C 70 °C
T5 70 °C 80 °C
T4 75 °C 85 °C
T3 80 °C 100 °C
T2 80 °C 100 °C
T1 80 °C 100 °C
At the same time the specified max. admissible
ambient temperature of 40 °C must not be exceeded.
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.