Flowserve VTP Wet Pit - Manual (Page 39)

VERTICAL TURBINE PUMPS (VTPS) CENTRIFUGAL PUMPS ENGLISH 71569224 – 10-13
Page 39 of 76 flowserve.com
If, after making the impeller adjustment the pump does
not deliver its rated capacity, the impellers can be
lowered one step at a time until the lowest possible
adjustment is achieved without the impellers dragging.
On the other hand, if the impellers appear to be
dragging after the initial adjustment, the unit should be
stopped and the impellers raised one step. Dragging
impellers will increase the load significantly and can
usually be heard and felt as increased vibration. A
sharp rise in motor amperage will occur when
impellers are dragging.
Impeller adjustment for a hollow shaft 5.3.1
driver
Impeller adjustment when using hollow shaft drivers is
as follows. The driver canopy will have to be removed
before beginning.
a) Install headshaft [10] if not already in place.
b) Install driver clutch in accordance with the driver
instruction manual and bolt into place.
c) Check shaft position. Lower shaft until there is a
definite feel of metal contacting metal. This
indicates the impellers are "on bottom" and in the
correct starting position for impeller adjustment.
d) Thread headshaft nut [66] down (right hand
threads) except 43 mm (1.7 in.) and larger sizes
that are having left hand threads, until impellers
are just raised off their seat and the shaft will
rotate freely.
e) Check a separate document that is supplied with
the pump that provides recommended impeller
setting and running clearance information..
Detail showing head shaft and lock screw
arrangement
If at any time during the life of this pump the
pumping conditions or total pump length changes,
contact the factory for recalculation of the impeller
setting.
f) Tighten the adjusting nut to match impeller setting
recommended by Flowserve. See table 5.3.1.1 &
5.3.1.2.
g) Using the cap screw provided, bolt the headshaft
nut [66] down & lock using lock screw [334] to the
motor coupling. See the details of head shaft and
lock screw arrangement under item (h) below.
Always lock headshaft nut by
tightening the lock screw [334] before starting driver.
Failure to do so could result in damage to the pump
and driver.
h) If a mechanical seal is used, adjust the
mechanical seal at this time.
Impeller clearance settings 5.3.1.1
Flowserve recommends the following impeller
settings based on the pump sizes.
If the pump size
is
Setting for
enclosed
impellers Setting for semi-
open impellers
Size 6 thru size
12
3~4 mm
(0.13~0.15 in.)
0.25 mm to 0.38 mm
(0.010 in. to 0.015 in.)
Size 14 and
above.
6~7 mm
(0.25~0.27 in.)
0.63 mm to 0.76 mm
(0.025 in. to 0.030 in.)
Shafts elongate due to the hydraulic thrust
of the pump and the impellers must be compensated
for this elongation. Shaft elongation varies for each
model depending upon the size, shaft length, shaft
diameter, impeller weight, number of stages. Please
see the documentation supplied along with the pump
for exact impeller setting value matched for the
specific pump that you have purchased
Head shaft nut adjustment 5.3.1.2
Head
Shaft size
mm
(in.)
Threads
per every
25 mm
(1 in.)
length of
the shaft
Lateral adjustment
mm (in.)
One complete
turn of nut will
result in shaft
movement of Each face of
nut
25 (1.0) 14
1.81
(0.070)
0.30
(0.012)
32 (1.25)
38 (1.50)
43 (1.69)
12
2.11
(0.080)
0.35
(0.014)
43 (1.69)
50 (1.94)
55 (2.19)
62 (2.44)
10
2.54
(0.100)
0.40
(0.016)
68 (2.69)
75 (2.94)
8
3.17
(0.120)
0.53
(0.020)
(334) LOCK SCREW
COUPLING
HEAD SHAFT (10)
HEAD SHAFT NUT (66)
DRIVER
GIB KEY(335)