Flowserve MSP - Manual (Page 29)

MSP USER INSTRUCTIONS ENGLISH - 07/14
Page 29 of 35
unless otherwise specified by mechanical seal
supplier.
Plan 32 is used in services containing solids or
contaminants where a suitable cleaner or cooler
extern flush will improve the seal environment. It is
also used to reduce flashing or air intrusion (in
vacuum services) across the seal faces by providing
a flush that has a lower vapor pressure or that will
raise the seal chamber pressure to an acceptable
level. The external flush shall be continuous and
reliable even during non-standard situations such as
start-up or shutdown. The external flush shall also be
compatible with the process stream because it will
leak from the seal chamber into the process fluid.
In Plan 32, the flushing product is brought from an
external source to the seal. This plan is almost
always used in conjunction with a close-clearance
throat bushing as barrier to isolate the pumped
product from the seal chamber.
Plan 54 pressurized dual seal systems are used in
services where no leakage to atmosphere can be
tolerated. A Plan 54 system consists of dual
mechanical seals with a liquid barrier fluid between
them. The barrier fluid is supplied from an external
source, which is pressurized to a pressure of
approximately 1.5 bar (23 psi) greater than the pump
seal chamber. Inner seal leakage will be barrier fluid
leakage into the product. There will always be some
leakage (max.5 ml/hour).
The barrier fluid pressure must not be less than the
sealed pressure. If it were, the failure of one inner
seal could contaminate the entire barrier fluid system
and cause additional seal failures.
CAUTION
Carefully consider the reliability of
the barrier fluid souce. If the souce is interrupted or
contanuinded, the resulting seal failures are very
expensive.
CAUTION
Open all necessary valves in the
cooling and auxiliary piping and check the flow.
Refer to the GA - drawing for the
required flushing fluid, pressure and flow.
Disassembly of the seal cartridge
is only allowed by authorized personal. Contact
Flowserve for any service of the mechanical seal. We
recommend to have a spare cartridge seal on stock
for easy replacement.
7.1.9 Dual Mechanical Seal unpressurized with
API – Plan 01+76
Refer to mechanical seal drawing and
auxiliary piping drawing.
The pump is equipped with a dual mechanical seal.
The cartridge design allows to change the
mechanical seal without taking it apart.
Try to turn the rotor by hand.If the
rotor cannot be turned, the pump must be
disassembled, refer to section 6.7.1 Dismantling
MSP.
Actions after start up:
Check all connections to the seal gland and the
mechanical seal itself against leakage. It is usual that
at the seal faces a small leakage occurs after start
up, which decreases with the time of operation and
should stop after the seal is run in. Check the
temperature of the seal gland. I slight increase of
temperature may be observed during the run in
period. Flushing of primary mechanical seal is
performed according to API 610 flushing plan 01.
Plan 01 is similar to a Plan 11 except that internal
porting is used to direct flow to the seal chamber from
an area behind the impeller near the discharge.
The product is led internally through a bore of a small
diameter (reduction of quantity) from the seal
chamber to flush the primary seal.
Plan 76 is suitable only for fluids, where no
condensation of the inner seal leakage or from the
collection system will occur.
Leakage from the inner mechanical seal is restricted
from escape by the containment seal and goes out
the containment seal vent. An orifice in the outlet line
of the collector restricts flow such that high leakage of
the inner seal will cause a pressure increase and
trigger the PSH set at a gauge pressure of 0,7 bar
(10 psi). The block valve in the outlet serves to isolate
the system for maintenance. It may also be used to
test the inner seal by closing while the pump is in
operation and noting the time/pressure build up
relationship in the collector. If specified, drain
connection on the piping harness may be used to
inject nitrogen or other gas for the purpose of testing
the containment seal as well as for checking for any
liquid build up.
Disassembly of the seal cartridge
is only allowed by authorized personal. Contact
Flowserve for any service of the mechanical seal. We
recommend to have a spare cartridge seal on stock
for easy replacement.
7.1.10 Dual Mechanical Seal pressurized with
API–Plan 32+53B
Refer to mechanical seal drawing and
auxiliary piping drawing.