Flowserve Gearex Rotary Gear Pumps External and Internal Bearing - Manual (Page 38)

EXTERNAL GEAREX USER INSTRUCTIONS ENGLISH 71569246 (2167B-E1)
Flowserve Pump Division 38
®
6.6 Renewal clearances
6.6.1 Clearance data for cast iron pump
Pump Size B C D E
Centre Distance
(inch)
1.750 2.125 3.375 4.375
Bore Diameter
(inch) 2.250 2.625 4.190 5.413
Clearance x.001
inch
4 to 6 6 to 8 6 to 8 9 to 11
6.6.2 Clearance data for carbon and stainless
steel pump
Pump Size B C D E
Centre Distance
(inch)
1.750 2.125 3.375 4.375
Bore Diameter
(inch)
2.260 2.635 4.200 5.423
Clearance x.001
inch Rotor/Bore
14 to 16 16 to 18 16 to 18 19 to 21
Clearance x.001
inch rotor End
4 to 6 6 to 8 6 to 8 9 to 11
Note that the clearance between the rotors and the
body is controlled by the dimensions and tolerances
on the manufacturing drawings. The rotor end
clearance is controlled by the rotor position on the
shaft, using an assembly jig, and the thickness of the
front gasket (which is standardized at 0.38 mm (0.015
inch) thick).
6.7 Disassembly
Note that replacement materials should be available
prior to disassembly to limit downtime.
6.7.1
Disassembly of external bearing pump
Refer to the sectional drawing in Section 12.3,
Figure 1, at the end of this manual.
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 and piping system if
necessary.
d) Disconnect stuffing box and other auxiliary piping.
e) Drain the pump body and lube oil cavities.
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) Remove the front (5) and rear (4) covers.
i)
Remove the front bracket ( from the pump. Mark
the "top" of the bracket to facilitate reassembly. If
the pump has mechanical seals, ensure that the
bracket is drawn smoothly off the shafts without
bumping. Note that if the pump is fitted with split
brackets the bearing housing half (3A) can be
separated from the seal housing to facilitate seal
maintenance.
j) Remove the front bearing snap ring (24) and
remove the bearing (14) from the bracket.
k) Back off the gland nuts and remove the
glands/mechanical seals (40).
l) Remove the timing gear locknuts (19) and
lockwashers (20).
m) Remove timing gears (13) and spacers (18) and
note marks for reassembly.
n) Remove the rear bracket from the pump. Mark
the "top" for reassembly. Note that if the pump is
fitted with split brackets the bearing housing half
(2A) can be separated from the seal housing to
facilitate seal maintenance.
o) Remove the bearing snap ring (25) and remove
the bearings (15).
p) Back off the gland nuts and remove
glands/mechanical seals (40).
q) The shafts (10,11) and rotors (12) may now be
removed from the pump body (1).
r) If fitted, remove the stuffing box restriction
bushings from the shaft and remove rotor spacers
if fitted.
s) 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.
t) Refer to section 6.8 Examination of parts.
6.7.2
Disassembly of internal bearing pump
Refer to the sectional drawing in Section 12.3,
Figure 2, at the end of this manual
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 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) Remove front head (5) and bearing housing (2). If
the pump is fitted with a mechanical seal, scribe