Richter RG5 - Manual (Page 4)

Series SCK mechanical seal RG-5, stationary, double, Page 4
with quench or pressurized
9220-065-en Revision 10
TM 7827 Edition 03/2010
4.2.3 Mechanical Seal RG-5, liquid sealed
A pump fitted with a double mechanical seal must not
be filled with a product before the available
pressurisation system provided has been started up.
Otherwise damage could occur, e.g. opening of the
wetted sealing gap, before start-up.
To guarantee safe operation, the pressure of the
barrier fluid must be 1-2 bar above the pressure of the
process medium at the mechanical seal at Q=0 m
3 /h.
To guarantee safe operation, the pressure of the
barrier fluid must be 1-2 bar above the pressure of the
process medium at the mechanical seal at Q=0 m
3 /h.
The required sealing pressure can be determined as
follows:
2/3 of the delivery pressure at Q = 0 m 3 /h
+ supply pressure
+ 1 - 2 bar safety margin
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
Are the available connections correctly made?
SE - barrier fluid inlet
SA - barrier fluid outlet
See also sectional drawing in Section 7 .
4.3 Improper operation and their
consequences (examples)
Improper operation, even for brief periods, may 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) can
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 .
5 Maintenance
The regulations of the mechanical seal
manufacturer must always be observed.
See also the installation and operating manual
for the SCK series.
5.1 Mechanical Seal RG-5, with
quench
Any quench fluid which has escaped must be
replenished in good time.
A difference is made between open and closed
quench systems.
It must be ensured with closed systems that the filling
level is always adequate. The quench fluid can be
enriched with the process medium through leaks and
is therefore to be completely changed from time to
time in line with the operating requirements.
If the filling level of the quench fluid has risen in a
storage container provided, it must be replaced
immediately.
5.2 Mechanical seal RG-5, liquid
sealed
It is important to replenish in good time any barrier
fluid which has escaped and to monitor the barrier
fluid pressure
The minimum barrier fluid pressure must never be
undershot as long as the pump housing is under
pressure.
Refer also to the description of the pressurisation
system used and
Section 4.2.2 .
If the barrier fluid pressure is too high, this indicates a
defect in the mechanical seal even though the
mechanical seal on the atmosphere side is completely
tight.
The pump must then be shut down so that no serious
damage occurs.
Substantial damage generally occurs if the aggressive
process medium enters the pressurisation system as
a result of a drop in the barrier fluid pressure to below
the minimum pressure.
If there is a risk of pressure surges in the plant,
precautions must be taken to prevent damage. For
example, the barrier fluid pressure can be increased
up to the pressure limit of the mechanical seal used.