Flowserve Gearex Rotary Gear Pumps External and Internal Bearing - Manual (Page 39)

EXTERNAL GEAREX USER INSTRUCTIONS ENGLISH 71569246 (2167B-E1)
Flowserve Pump Division 39
®
the location of the seal on the shaft, loosen set
screws holding the rotating head to the shaft and
remove seal .
i) Remove capscrews holding end cover (4) and
bearing housing (3) to body (1). Remove rear
cover (4). (Mark top to facilitate reassembly).
j) Remove rear bearing housing and rotating
element together from the body.
k) Remove the locknuts (19) and lockwashers (20)
from shafts.
l) Remove timing gears (13) and spacers (18) and
mark for reassembly.
m) Remove bearing housing (3) from shafts.
n) Remove bearing outer races (16) from housings.
o) The pumping rotors are pressed on and keyed to
the shafts. They should not be disturbed unless
replacement is necessary. If replacement is
necessary, mark the shaft at each end of the rotor
and remove from the shaft in a press.
p) 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 sectional drawing furnished with the pump
or to the typical drawing in Section 12.3 of this
manual. If a sectional is not available, it can be
requested from the factory.
6.9.1 Reassembly of external bearing pump sizes
B, C and D
a) Inspect all new parts. Remove all nicks and burrs
which may have occurred in handling.
b) If new rotors are required, they should be installed
on the shafts now. Apply anti-seize compound to
the shafts at the rotor location. Fit the key into the
shaft keyway. Slide the rotors onto the shafts
from the end opposite the time gear location.
(There is a reduced diameter lead on section
here). Fit the rotor and shaft into a press and
push the rotor on until it aligns with the reference
marks scribed during disassembly.
c) Apply anti-seize compound to the shafts at the
location of the front bearing inner race (16).
Install the inner race on the shaft. Use an
induction heater or hot oil bath to first heat the
race. (90
°
C (200
°
F) recommended).
d) Temporarily install the timing gears (13) and keys
(22) onto the shafts. (Spacers and locknuts, etc.,
are not required.)
e) Intermesh the drive and driven shafts, taking care
to align the timing marks on the face of the timing
gears. Slide the shaft assembly into the body and
remove the timing gears and keys.
f) If rotor spacers are required, slide them onto the
shafts and up against each end of the rotors.
g) Install the thrust bearings (15) in the rear bearing
housing (2A).
h) Mount a new end flange gasket (50) on the rear of
the body (1).
i) Mount the rear bracket (2) with oil seals (27) in
place on the body, noting the top mark. If solid
glands are used, they must be mounted in the
bracket prior to this operation. Note that if the
pump is fitted with split brackets the seal housing
(2B) can be mounted first, then the seal assembly
(don’t tighten drive screws at this time) followed
by the bearing half (2A).
j) If pumps are fitted with shaft mounted (non
cartridge) mechanical seals, the rotating heads of
the seals must be in the correct position on the
shafts prior to mounting the brackets. If a new
rotating element is being installed in the pump, do
not mount mechanical seal heads at this time.
Refer to section 6.10.1.1 External bearing pump.
k) Replace the rear bracket to body capscrews (55)
and tighten finger tight only.
l) Mount the timing gear spacers (18) and timing
gears (13) on the appropriate shafts.
m) Install locknuts (19) and lockwashers (20).
n) Install a gasket (50) on the rear of the bracket (2)
and install the rear cover (4).
o) If a new rotating element is being installed, refer
to section 6.10.1.1 External bearing pump before
proceeding further.