Flowserve Mark 3 - Manual (Page 26)

USER INSTRUCTIONS MARK 3 High Silicon Iron ENGLISH 71569249 09-04
®
Ensuring that NPSH
A
is larger than
NPSH
R
by the suggested margin will greatly enhance
pump performance and reliability. It will also reduce
the likelihood of cavitation, which can severely
damage the pump.
5.10.2 Specific gravity (SG)
Pump capacity and total head in meters (feet) of
liquid do not change with SG, however pressure
displayed on a pressure gauge is directly proportional
to SG. Power absorbed is also directly proportional
to SG. It is therefore important to check that any
change in SG will not overload the pump driver or
over pressurize the pump.
5.10.3 Viscosity
For a given flow rate the total head reduces with
increased viscosity and increases with reduced
viscosity. Also for a given flow rate the power
absorbed increases with the increased viscosity, and
reduces with reduced viscosity. It is important that
checks are made with your nearest Flowserve office if
changes in viscosity are planned.
5.10.4 Pump speed
Changing the pump speed affects flow, total head,
power absorbed, NPSH
R
, noise and vibration levels.
Flow varies in direct proportion to pump speed. Head
varies as speed ratio squared. Power varies as speed
ratio cubed. If increasing speed it is important to ensure
the maximum pump working pressure is not exceeded,
the driver is not overloaded, NPSH
A
> NPSH
R
and that
noise and vibration are within local requirements and
regulations.
6 MAINTENANCE
It is the plant operator's responsibility to ensure
that all maintenance, inspection and assembly work
is carried out by authorized and qualified personnel
who have adequately familiarized themselves with
the subject matter by studying this manual in detail.
(See also section 1.6.2.)
Any work on the machine must be performed when it
is at a standstill. It is imperative that the procedure
for shutting down the machine is followed, as
described in section 5.9.
On completion of work all guards and safety devices
must be re-installed and made operative again.
Before restarting the machine, the relevant
instructions listed in section 5, Commissioning, start
up, operation and shut down must be observed.
Oil and grease leaks may make the ground
slippery. Machine maintenance must always
begin and finish by cleaning the ground and the
exterior of the machine.
If platforms, stairs and guard rails are required for
maintenance, they must be placed for easy access to
areas where maintenance and inspection are to be
carried out. The positioning of these accessories
must not limit access or hinder the lifting of the part to
be serviced.
When air or compressed inert gas is used in the
maintenance process, the operator and anyone in the
vicinity must be careful and have the appropriate
protection.
Do not spray air or compressed inert gas on skin.
Do not direct an air or gas jet towards other people.
Never use air or compressed inert gas to clean
clothes.
Before working on the pump, take measures to
prevent the pump from being accidentally started.
Place a warning sign on the starting device:
"Machine under repair: do not start."
With electric drive equipment, lock the main switch
open and withdraw any fuses. Put a warning sign on
the fuse box or main switch:
"Machine under repair: do not connect."
Never clean equipment with flammable solvents or
carbon tetrachloride. Protect yourself against toxic
fumes when using cleaning agents.
Refer to the parts list shown in section 8 for item
number references used throughout this section.
6.1 Maintenance schedule
It is recommended that a maintenance plan and
schedule be implemented, in accordance with these
User Instructions, to include the following:
a) Any auxiliary systems installed must be monitored,
if necessary, to ensure they function correctly.
b) Gland packing must be adjusted correctly to give
visible leakage and concentric alignment of the
gland follower to prevent excessive temperature
of the packing or follower.
c) Check for any leaks from gaskets and seals. The
correct functioning of the shaft seal must be
checked regularly.
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