Richter Mechanical Seals - Manual (Page 4)

Series SCK, mechanical seal, external, single Page 4
single with double lip seal on the wetted side
single with lip seal on the atmosphere side, with quench
9220-060-en Revision 10
TM 7827
Edition 03/2010
4 Commissioning / Shutdown
4.1 Initial commissioning
See installation and operating manual for the series
SCK.
4.2 Mechanical seals
The design and material combination are specified in
the data sheet.
The proper condition of the components and
the protective facilities must be ensured to
prevent any risk from escaping medium.
The regulations and recommendations of
the mechanical seal manufacturer must
always be observed.
4.2.1 Use in an explosive area
Use in an explosive area means that only
mechanical seals may be employed which
permit observation of temperature.
The operating manual of the respective mechanical
seal manufacturer is an integral part of this general
operating manual.
This permits, amongst other things, the calculation of
the expected surface temperature at the mechanical
seal. The suitability for the permissible temperature
class as per ATEX is hereby given.
CAUTION:
The permissible temperature class of the complete
unit (pump, mechanical seal, coupling, motor) is
determined by the lowest temperature class of the
individual components.
Example: Pump T4, mechanical seal T3,
coupling T4, motor T4
In both cases the unit may only be used in
atmospheres which may ignite above the temperature
class T3, i.e. >200 °C (>392°F).
4.2.2 External, single mechanical seal
Pumps fitted with a single mechanical seal must
not be started up before they are filled with
medium.
Otherwise the single mechanical seal is not lubricated
and cooled and could be damaged.
Mechanical seal guard mounted?
See sectional drawing in Section 7.
4.2.3 Single mechanical seal with lip seal
Design and material combination are specified in the
data sheet.
A pump with a flushed mechanical seal may not
be started up until the flushing system is in
operation and the pump is filled with medium.
The pressure of the flushing medium must be higher
than the medium pressure in the sealing chamber.
The required sealing pressure can be determined as
follows:
2/3 of the delivery pressure at Q = 0 m 3 /h
+ supply pressure
The supply pressure is measured in bar at the pump
suction nozzle. If no measuring point is available, the
supply pressure can be calculated using the following
formula.
Using the same formula, the delivery pressure at
Q=0 m
3 /h can be determined with the pump
characteristic curve.
2 , 10
) (kg/dm x (mFS) H
= (bar) p
3
p = supply pressure or delivery pressure
H = supply height or delivery head
= density
The pressure is to be set so that a minimum flushing
flow of 10 l/h is observed.
4.3 Improper operation and their
consequences (examples)
Improper operation, even for a short time, can
result in serious damage to the unit.
In connection with explosion protection,
potential sources of ignition (overheating, electrostatic
and induced charges, mechanical and electric sparks)
may result from these inadmissible modes of
operation; their occurrence can only be prevented by
adhering to the intended use.
For examples, see installation and operating manual
SCK, Section 6.6.