Functional Recommendations - Flowserve Allpac 4 Series User Instructions

and face materials require special precautions to prevent damage to the seals during these
tests. For example, on seals with two hard faces, the seals may be provided with faces in
alternate materials more suitable for the pump test medium. These faces are to be replaced
with faces in the selected materials at the conclusion of the testing. A mechanical seal equipped
with a hard face comination can be safely operated on water provided the pressure does not
exceed 5 bar (72.5 psi) and the speed does not exceed 10 m/s (32.8 fps).
When high temperature seals with graphoil gaskets are tested on water during a pump
performance test, the seals must be carefully dried after the test to prevent vaporization of
water absorbed by the gaskets when the pump is brought to its (high) operating temperature.
Contact your Flowserve representative for additional information.

9. Functional Recommendations

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9.1 The pressure and temperature in the seal chamber or of the barrier fluid must not
exceed the recommended maximum seal limits. The shaft speed must also not exceed
the seal's limits.
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9.2 For seals using external cooling and/or an external flush, apply cooling and / or flush
prior to seal start-up. Avoid inadvertent operation of valves located in the cooling sys-
tem that might result in shutting off the cooling flow.
9.3 Single and dual non-pressurized (tandem) seals require adequate vapor pressure margin
in the seal chamber to prevent flashing of the product at the seal faces.
9.4 Dual non-pressurized (tandem) seals require the buffer fluid pressure to be maintained
at a value lower than the seal chamber pressure. Buffer fluid pressure is usually equal
to atmospheric or vapor recovery system pressure, unless otherwise specified.
9.5 Dual pressurized (double) seals require the barrier fluid pressure to be maintained at
least 2 bar (30 psi) above the seal chamber pressure, unless otherwise specified. It is
imperative to pressurize the barrier prior to pressurizing the equipment. Likewise,
do not de-pressurize the barrier system until the equipment has been fully isolated,
depressurized and vented.
9.6 Flowserve can supply information on barrier fluid temperature and flow requirements
based on product type, seal size, product temperature, barrier fluid characteristics
and shaft speed. The buffer/barrier fluid must contain little or no additives for anti-wear/
oxidation. Automotive antifreeze should never be used. Ensure that the barrier fluid is
clean and compatible with the product.
9.7 This seal is designed to resist corrosion by the product(s) listed on the assembly
drawing. Do not expose the seal materials to products other than those shown on
the assembly drawing. The seal assembly drawing lists the materials of construction.
Consult your Flowserve representative when in doubt or when using the seal for another
application than for which it was selected.
General Installation and Maintenance Instructions for Machinery Components
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