Flowserve LN - Manual (Page 22)

LN, LNE, LNH, LNV, LNEV, LNC and LNEC USER INSTRUCTIONS ENGLISH 71576423 11-09
Page 22 of 32 flowserve.com
6.6 Examination of parts
Used parts must be inspected before
assembly to ensure the pump will subsequently run
properly.
In particular, fault diagnosis is essential to enhance
pump and plant reliability.
6.6.1 Casing and impeller
Inspect for excessive wear, pitting, corrosion, erosion or
damage and any sealing surface irregularities. Replace
as necessary.
6.6.2 Shaft and sleeve
Replace if grooved, pitted or worn.
6.6.3 Gaskets and O-rings
After dismantling, discard and replace.
6.6.4 Bearings
It is recommended that bearings are not re-used after
any removal from the shaft.
6.7 Assembly
To assemble the pump consult the sectional
drawings, see section 8, Parts list and drawings.
Ensure threads, gasket and O-ring mating faces are
clean. Apply thread sealant to non-face sealing pipe
thread fittings.
6.7.1 Wear rings
a)
Impeller rings (when fitted) should be heated up
using a hotplate or hot oil bath and then slipped
onto the impeller and pressed down to the
shoulder. (Do not use a steel hammer to knock it
into position.)
b) Drill and tap equi-spaced holes into the
diametral mating faces of the ring and impeller
and insert grubscrews. (The existing half-tapped
holes from the removed impeller ring cannot be
re-used).
c) Slip the casing wear rings over the impeller hubs
before mounting the rotor unit into the lower half
casing.
6.7.2 Rotor unit
The two shaft sleeves and shaft nuts clamping the
impeller define its position on the pump shaft and
hence in the pump casing.
6.7.3 Shaft seal – stuffing box
a)
Fit impeller key and slide impeller onto shaft.
b) Insert O-ring into shaft sleeves and slide sleeves
along shaft up to the impeller hubs.
c) Lightly lubricate the shaft and O-ring for easier
assembly.
d) Tighten and adjust the shaft nuts so that they
are equi-distant about the pump centre line.
e) Lock the shaft nuts in place with grubscrews.
6.7.4 Shaft seal – mechanical seal
For assembly of mechanical seal refer to the seal
arrangement drawing supplied with the contractual
documentation.
6.7.5 Bearings
Before mounting the bearings, proceed as follows:
a) Mount the flingers onto the shaft and slide the
bearing cover over the shaft.
b) Position the bearings onto the shaft.
6.7.6 Rotor unit
After completion of preceding steps, carefully place the
rotor into the lower half pump casing.
6.7.7 Casing gasket
a)
The gasket must be cut from asbestos free
sheet material of 0.8 +0.1/-0.05mm (1/32")
thickness, by following the actual inner casing
contour of the lower half casing. Special care
must be exercised at the bores and stuffing box.
b) Position gasket carefully onto the cleaned
surface of the lower half casing.
c) Coat the flange surface of the wall between
suction and discharge side with an adhesive
paste (Cyanoacrylate or RTV silicone).
d) Place upper half casing onto pump ensuring
dowels make correct alignment.
e) Tighten upper half casing flange nuts to correct
torque.