Flowserve Twin Screw Rotary - Manual (Page 41)

TWIN SCREW PUMPS. ORIGINAL USER INSTRUCTIONS. ENGLISH. 71569243 – 07/10
Page 38 of 53
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L (long) and those on the driven shaft are
stamped S (short) and that the stamped
letters face out. This is important when
reassembling the pump. Remove the timing
gears [2810].
k) Loosen gland nuts [6580.1] and backoff all
packing glands [4130]. If the pump is fitted
with mechanical seals [4200.1] refer to the
sectional drawing or mechanical seal drawing
for specific disassembly requirements.
l) Remove the front bracket [6160.1] from the
body and mark the top to facilitate
reassembly. Note that if the pump is fitted with
split brackets the seal and bearing housing
halves can be separated at this point to
facilitate seal maintenance. Note the markings
on the halves for reassembly.
m) Remove the rear caps [3510] from the rear
bearing bracket [6160.2].
n) Bend up the locking tab on the rear bearing
lockwasher [6540.1] and remove the nut
[5260.1] and washer.
o) Remove the rear bracket [6160.2]. Note that if
the pump is fitted with split brackets the seal
and bearing housing halves can be separated
at this point to facilitate seal maintenance.
Note the markings on the halves for
reassembly.
p) Remove the rear bracket bearings [3011], and
spacers if so equipped, again noting the
markings on the spacers.
q) Refer to the INSPECTION AND OVERHAUL
section of this manual.
6.7.3
Disassembly of internal bearing pump
a) Ensure that the driver is locked out and cannot be
accidentally started.
b) Ensure that the pump is isolated from the system
by closing off all primary and auxiliary piping
valves associates with the pump.
c) Flush the pump body [1110] and piping system if
necessary.
d) Disconnect stuffing box and other auxiliary piping.
e) Drain the pump.
f) Remove coupling guard and uncouple the pump
from the driver.
g) Remove the pump half coupling. If a spacer
coupling is not used, it will be necessary to
remove either the pump or the driver from the
baseplate to do this.
h) If the pump is fitted with a mechanical seal, scribe
the location of the seal on the shaft, loosen set
screws holding the rotating head or drive collar to
the shaft and remove seal. Remove front head
[3717.1].
i) Remove capscrews holding rear end cover
[3510.1] and rear head [3717.2] to body. Remove
rear cover. (Mark top to facilitate reassembly).
j) Bend up the locking tab on the thrust bearing
lockwashers [6540.1] and remove nuts [5260.2]
and washers.
k) Remove rear head [3717.2] from the pump body
[1110] and remove bearings [3011] from the head.
l) Remove rear bearing spacers [2164] (not used on
all sizes) and note spacer markings for
reassembly on correct shaft.
m) Remove shafts [2120, 2140] from pump body. It is
recommended that even if timing gears [2810] are
not to be replaced they should be removed form
the shafts. If replacement is required it will be
necessary to remove the front bearing inner races
from the shafts by heating or splitting. Refer to the
timing gear replacement section of this manual.
n) Refer to section 6.8 Examination of parts.
6.8 Examination of parts
a) Inspect the pumping rotors and body bores for
excessive wear or damage.
If the difference between the body bore diameter
and the pumping rotor diameter is twice the
quoted operating clearance or greater, an
evaluation of the pump's performance may be
required.
b) Inspect bearings for wear and the presence of
foreign matter. Replace if damaged or worn.
c) Inspect all gaskets and 'O’ rings for damage. It is
recommended that these items be replaced to
avoid problems with reassembly.
d) Inspect and clean internal bore of stuffing box.
e) Clean and inspect all gasketed surfaces.
f) Clean the shafts and inspect for corrosion,
evidence of cracking, fatigue, or mechanical
damage. Remove all nicks and burrs. Check that
shafts are straight within 0.050 mm (0.002 inch).
6.9 Assembly
Care must be taken during the
assembly operation to avoid contamination of the
parts with dirt, dust or other foreign matter.
Refer to the typical sectional drawing furnished in
Section 12.4 of this manual. If a sectional is not
available, it can be requested from the factory.