Flowserve Seal Gard - Manual (Page 6)

6
3.3 Seal Gard II for a Double Flowserve seal
Circulation of Clean External Flush, Plan 54
(also for a Tandem Flowserve seal or a Packed "Balanced" Stuffing Box)
Type of Installation Double Flowserve seal or flush to and
from lantern ring taps
Flush PlaN 54
Part Code UKDOOSG2020 0 to 20 gph
UKDOOSG2040 0 to 40 gph
Operation (See Figure 2)
• Open flush supply valve or flush to and from
• Open supply control valve and close return-from-seal control valve
• Start up equipment
• Set return-from-seal valve to flow needed to remove seal
generated heat
• Gradually close supply control valve until flow in return-from-
seal drops slightly, then open supply control valve 1/8 turn
• For packing, balance the flows of the two meters to minimize
product dilution and product loss
• Record supply flow, return-from-seal flow, and pressure on
operators log. Flows will not match exactly, ±10%, due to
system pressure drop,
• Set optional low flow alarm
• Set optional high flow alarm
Note: With double or tandem seals, any outer seal leakage can be observed and
reported. The condition of the inner seal in a double seal can be checked by clos-
ing the outlet valve. If the supply flowmeter shows no flow, the inner seal is intact.
If the supply flowmeter shows a flow, the inner seal is leaking and repairs should
be scheduled. As a temporary measure, leave the return-from seal valve closed
and set the supply valve to minimize the flow of barrier water into the product.
This arrangement can also be used to supply the buffer fluid between the inner
and outer seals of a tandem Flowserve seal, Plan 52. Here, the buffer fluid is
maintained at a pressure below that of the product acting on the inner seal and
is often atmospheric. Set the desired flow rate to remove seal generated heat
by adjusting the supply control valve. Set the return-from-seal control valve to
maintain the desired pressure between the inner and outer tandem seals. When
the inner seal of a tandem seal fails, the flow from the seal assembly will be
higher than the flush supply to the seal and the pressure gauge will show product
pressure.