Flowserve LNN - Manual (Page 19)

LNN, LNNV, LNNC USER INSTRUCTIONS ENGLISH 71569074 06-14
Page 19 of 56
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A spool piece should be installed in the
suction line so that the suction strainer may be
installed and removed with a pressure gauge
between the strainer and pump.
4.6.4
Discharge piping
See section 4.6.3 for typical pipe work design.
A non-return valve should be located in the discharge
pipe work to protect the pump from excessive back
pressure and hence reverse rotation when the unit is
stopped.
Pipe work reducers should have a maximum total
angle of divergence of 9 degrees.
Fitting an isolation valve will allow easier maintenance.
4.6.5
Auxiliary piping
4.6.5.1
Drains
Pipe pump casing drains and gland leakage to a
convenient disposal point.
4.6.5.2
Pumps fitted with gland packing
When suction pressure is below ambient pressure it is
necessary to feed the gland packing with liquid to
provide lubrication and prevent the ingress of air. This
is normally achieved with a supply from the pump
discharge volute to the stuffing box. A control valve or
orifice plate may have been fitted into the supply line to
control the pressure to the gland/stuffing box.
If the pumped liquid is dirty and cannot be used for
sealing, a separate clean compatible liquid supply to
the gland at 1 bar (15 psi) above suction pressure is
recommended.
4.6.5.3
Pumps fitted with mechanical seals
Single seals requiring re-circulation will normally be
provided with the auxiliary piping from pump casing
already fitted.
If the seal requires an auxiliary quench then a
connection must be made to a suitable source of
liquid flow, low pressure steam or static pressure from
a header tank. Recommended pressure is 0.35 bar
(5 psi) or less. Check General arrangement drawing.
Special seals may require different auxiliary piping to
that described above. Consult separate User
Instructions and or Flowserve if unsure of correct
method or arrangement.
For pumping hot liquids, to avoid seal damage, it is
recommended that any external flush/cooling supply
be continued after stopping the pump.
4.6.6
Final checks
Check the tightness of all bolts in the suction and
discharge pipe work. Check also the tightness of all
foundation bolts.
4.7 Final shaft alignment check
After connecting piping to the pump, rotate the shaft
several times by hand to ensure there is no binding
and all parts are free.
Recheck the coupling alignment, as previously
described, to ensure no pipe strain. If pipe strain
exists, correct piping.
4.8 Electrical connections
Electrical connections must be made by
a qualified Electrician in accordance with relevant
local national and international regulations.
It is important to be aware of the EUROPEAN
DIRECTIVE on potentially explosive areas where
compliance with IEC60079-14 is an additional
requirement for making electrical connections.
It is important to be aware of the EUROPEAN
DIRECTIVE on electromagnetic compatibility when
wiring up and installing equipment on site. Attention
must be paid to ensure that the techniques used during
wiring/installation do not increase electromagnetic
emissions or decrease the electromagnetic immunity of
the equipment, wiring or any connected devices. If in
any doubt contact Flowserve for advice.
The motor must be wired up in
accordance with the motor manufacturer's instructions
(normally supplied within the terminal box) including any
temperature, earth leakage, current and other protective
devices as appropriate. Check the identification
nameplate to ensure the power supply is appropriate.
A device to provide emergency stopping must
be fitted.
If not supplied pre-wired to the pump unit, the
controller/starter electrical details will also be supplied
within the controller/starter.