Flowserve Twin Screw Rotary - Manual (Page 42)

TWIN SCREW PUMPS. ORIGINAL USER INSTRUCTIONS. ENGLISH. 71569243 – 07/10
Page 39 of 53
®
6.9.1 Reassembly of external bearing pump-Rear
Timing Gear configuration.
a) Inspect all new parts. Remove all nicks and
burrs which may have occurred in handling.
b) Intermesh the drive [2120] and driven [2140]
shafts, taking care to line up the ends of the
pumping screws. Slide the shaft assembly
[2120,2140] into the pump body [1110].
c) Use an induction heater or hot oil bath to heat
the bearing race to 200 deg F (recommended)
and install the bracket bearing races on the
shafts and against the locating shoulders.
d) Mount mechanical seal heads (if fitted with
shaft mounted seals) on the shafts using the
marks made during disassembly to position.
Note: If a new rotating element is being
assembled into the pump, do not mount the
mechanical seal heads at this time. Refer to
section titled NEW ROTATING ELEMENTS.
e) Mount a new end flange gasket [4590.2] on
the rear end of the body [1110].
f) Mount the rear bracket [6160] with bearing
outer races [3012], lip seals [4310.2] and
mechanical seal stationary seats (if fitted) in
place. Note the top mark so that the bracket
will be replaced in the original position as
assembled in the factory.
g) Note: Front and rear brackets are
identical. Care must be taken to avoid
interchanging them to avoid dowelling
problems.
h) Replace the rear bracket [6580.2] to body
nuts and tighten finger tight only.
i) Mount timing gears [2810] and spacers
[2164.3] onto the shafts in the exact location
from which they were removed. Note that,
when timing gears are installed correctly,
original punch marks on teeth will line up per
Figure 8.
j) Mount a new flange gasket [4590.2] on the
rear bracket.
k) Mount gear housing [1600] to rear bracket.
Insert dowel pins [6810.1] and tighten all
capscrews.
l) Mount the rear (ball) bearings [3051] into the
gear housing and onto the shafts.
m) Slide the rear bearing lockwashers onto the
shafts and fit the bearing locknuts [5260].
Tighten the locknuts snugly but avoid
overtightening as the lockwasher anti-rotation
tab could be damaged. Bend one lockwasher
tang on each lockwasher to lock the nuts.
n) Replace the rear caps [3510] into the same
bore from which they were removed. If new
bearings are being installed, check that the
insertion length of the cap is greater than the
recess in the gear housing bore by
approximately .001 to .002. Any larger and
tightening of the rear cap capscrews will
distort the cap. Any shorter and contact will
not be made with the bearing by the cap.
o) Note: If a new rotating element is being
installed into the pump refer to the section
titled NEW ROTATING ELEMENTS before
proceeding further.
p) Mount a new end flange gasket [4590.2] on
the front end of the body [1110].
q) Mount the front bracket [6160] with bearing
outer races [3012], oil seals [4310.2] and
mechanical seal stationary seats (if fitted) in
place.
r) Replace the front bracket to body nuts
[6580.2] and tighten finger tight only.
s) Line up dowel pin holes in front and rear
brackets and insert dowel pins [6810.3].
Tighten all capscrews and nuts. The pump
should now turn freely. If pump does not turn
freely, refer to Section 6.11 further on in the
manual covering this.
t) Mount a new flange gasket [4590.2] on the
front bracket.
u) Mount front cover [1510] with oil seal [4310.3]
in place, on the front bracket. Insert dowel
pins [6810.2] and tighten all capscrews.
6.9.2 Reassembly of external bearing pump-Front
Timing Gear configuration.
a) Inspect all new parts. Remove all nicks and
burrs which may have occurred in handling.
Care must be taken to ensure parts are not
contaminated with dirt, dust or other foreign
material.
b) Intermesh the drive [2120] and driven [2140]
shafts, taking care to line up the ends of the
pumping screws. Slide the shaft assembly
into the pump body.
c) Install the rear bearing spacer(s) (if equipped)
on the same shaft from which they were
removed.
d) Mount a new end flange gasket [4590] on the
rear end of the pump body [1110].
e) Mount the rear bracket [6160.2], with lip seals
[4310.1] in place, on the body noting the
orientation of the “top” mark. If solid packing
glands [4130] are used they must be mounted
in the bracket prior to this operation. If the
pump is fitted with shaft mounted (non