Flowserve ISC - Manual (Page 15)

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.2 For running a dual pressurized seal (double seal), supply a clean
compatible barrier fluid to the inlet port at a pressure at least 25
psi (70 kPa) above the seal chamber pressure (see Figure 9). The
pressure of the barrier fluid must not exceed the recommended
maximum pressure. Flowserve can supply information on barrier
fluid flow requirements based on seal size, product temperature,
barrier fluid characteristics, and shaft speed.
Monitoring the liquid circulation is a recommended measure
for ensuring that the mechanical seal runs properly.
Suitable measures must be implemented to prevent errors in
the handling of shut-off and throttling devices installed in the
fluid supply.
8.3 For running a dual nonpressurized seal (tandem seal), supply a
clean compatible buffer fluid to the inlet port at a pressure below
the seal chamber pressure (See Figure 0). The pressure in the
seal chamber must not exceed the recommended maximum
pressure. Flowserve can supply information on buffer fluid flow
requirements based on seal size, product temperature, buffer fluid
characteristics, and shaft speed.
8.4 The Flowserve Supply Tank is designed to work with the ISC Dual
Seal to form a self-contained sealing system. The new circulating
feature in the ISC provides a positive barrier fluid flow from the
seal cavity to the Supply Tank and back to the seal. In most cases
the natural cooling of the piping and tank are adequate to remove
seal generated heat. Cooling coils are available with the Supply
Tank to increase heat dissipation. The Supply Tank can be used
with the ISC Dual Seal in both the double or tandem operating
modes.
2
Recommendation: For enhanced seal performance and reduced
coking, use DuraClear as a barrier fluid. Refer to DuraClear bro-
chure FSD23 or contact a Flowserve seal application engineer for
further details.
Figure 10.
Tandem ISC with Supply Tank