Richter MNKA-B Series (ASME) - Manual (Page 7)

Installation and Operating Manual
Series MNKA-B, acc. to ASME/ANSI
9250-055-en Revision 01
TM 5976 MPE/Wm Page 7 Edition 10/2004
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 are
induced on the inner and outer magnet assemblies
and an inadmissible rise in temperature may occur.
The situation is to be remedied by providing
appropriate monitoring facilities. See Section 5.6.
The plant NPSH value (NPSHA) should be
1.64 ft (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.
2.5.3 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.
2.5.4 Identification
The identification on the pump relates to the
pump section. A separate declaration of
conformity must be provided for the motor and
for other attachments as well as corresponding
identification.
Example of the identification of the pump section:
CE Ex II 2 G/D T1-T... .
The identification indicates the theoretically available
range of the temperature classes. The admissible
temperature depending on the pump design are
derived in accordance with Section 2.5.7. The same
applies to the drive.
For an overall unit (pump, coupling, motor) with
various temperature classes, the lowest class in each
case applies as follows:
Example 1: Pump T3, motor T4
T3 applies, i.e. the unit may only be used in
atmospheres which may ignite at temperatures
< 392 °F (200 °C) (+ safety margin). The maximum
medium temperature of the pump for this example is
356 °F (180 °C), see table in Section 2.5.7.
Example 2: Pump T4, Motor T3
T3 applies, i.e. the unit may only be used in
atmospheres which may ignite at temperatures
< 392 °F (200 °C) (+ safety margin).
2.5.5 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.
2.5.6 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 (casing) 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 fluid.
Operation of the pump outside the admissible
operating range may also lead to dry-running (e.g.
due to evaporation in the interior).
2.5.7 Temperature limits
In normal operating mode the highest
temperatures are to be expected on the shaft
seal (only with oil lubrication), on the inner
races of the rolling bearings and at high medium
temperatures on the surface of the pump housing.
In the case of fluids > 104 °F (40 °C) the surface
temperature of the pump housing (casing) is generally
lower than the temperature of the liquid as the 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.