Flowserve Tandem Seal - Manual (Page 7)

7
5 Tandem Sealing Systems for Supply Tanks
Pre-engineered and assembled for safe, reliable handling of toxic, flammable,
carcinogenic, or other reactive organic compounds. A tandem seal configuration
is used when a back-up safety seal is required, usually in critical process pumps.
But tandem seal arrangements produce weepage across the face of the primary
seal. When pumping a hazardous fluid, this weepage should not be vented to
the atmosphere. Containment and disposal must be a safe, controlled process.
Flowserve’s supply tank with the tandem sealing system (TSS) is the ideal solu-
tion.
Operation
During normal operation of
the tan dem sealing system,
potentially hazardous seal weep-
age is vented to a safe disposal.
In the event of a primary seal leak
or failure, as the secondary seal
takes over, pressure builds up
across the orifice at the top of the
supply tank assembly. This buildup
is then detected by the pressure
switch which activates an alarm.
A signal from the pressure switch
also closes the vent solenoid valve
to isolate the hazardous vapor flow
until orderly process shutdown and
maintenance can be performed.
(See Figure 3) Included in the
tandem sealing system option are
a pressure gage, pressure switch,
solenoid valve, globe valves, ar-
mored level gage, and orifice.
Models available
Supply tank models for use with
tandem sealing systems are made
from heavy duty 304 stainless steel
with pressure ratings of 400 psig
(2760 kPa) or 900 psig (6200 kPa),
and from carbon steel with a rating
of 900 psig (6200 kPa). Order with
or without cooling coils.
Plan 52 Supply Tank
Figure 4