Flowserve S-series PolyChem - Manual (Page 34)

USER INSTRUCTIONS POLYCHEM S-SERIES ENGLISH 71569207 11-08
Page 34 of 52
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Place a second mark with the felt tip pen on the
bearing carrier and then rotate 23 indicator patterns
counter-clockwise from this second mark. Uniformly
tighten the set screws [6570.3] in incremental steps
to lock the bearing carrier in place. The impeller is
now set 2.3 mm (0.09 in.) off of the casing.
6.7.2 Installation and clearance setting for front
vane open style impellers
Install the impeller [2200] by screwing it onto the shaft
(use heavy gloves) until it firmly seats against the
shaft shoulder.
The impeller could have sharp edges,
which could cause an injury. It is very important to
wear heavy gloves.
Tighten the impeller with the impeller wrench from the
Flowserve impeller tool kit. To do this, grasp the
impeller in both hands and, with the impeller wrench
handle to the left (viewed from the impeller end of the
shaft - Figure 6-4), spin the impeller forcefully in a
clockwise direction to impact the impeller wrench
handle on the work surface to the right. (Figure 6-5.)
Do not attempt to tighten the impeller
on the shaft by hitting the impeller with a hammer or
any other object or by inserting a pry bar between the
impeller vanes. Serious damage to the impeller may
result from such actions.
Like all front vane open style impellers, the Flowserve
open impeller clearance must be set off the casing.
The casing must be installed to accurately set the
impeller clearance.
Attach the power end/rear cover plate assembly to
the casing. Loosen the set screws [6570.3] and
rotating the bearing carrier [3240] clockwise until the
impeller comes into light rubbing contact with the
casing. Rotating the shaft at the same time will
accurately determine this zero setting. Using a felt tip
pen place a reference mark on both the bearing
housing and the carrier.
Now rotate the bearing carrier counter-clockwise to
get the proper clearance. Refer to Figure 5-10 for the
proper impeller clearance settings. Rotating the
bearing carrier the width of one of the indicator
pattern moves the impeller axially 0.1 mm (0.004 in.).
(See Figure 6-6.) To determine how far to rotate the
bearing carrier divide the desired impeller clearance
by 0.1 mm (0.004 in.) (one indicator pattern).
Tightening the set screws [6570.3] will cause the
impeller to move 0.05 mm (0.002 in.) away from the
casing because of the internal looseness in the
bearing carrier threads. This must be considered
when setting the impeller clearance. Rotate the
bearing carrier counter-clockwise the required
amount to get the desired clearance to the casing.
Lastly, uniformly tighten the set screws
[6570.3] in incremental steps up to the final torque
value to lock the bearing carrier in place.
See section 5.3 for impeller clearance settings.
Example. The impeller of a pump is to be placed in a
service based an operating temperature of 65 °C
(150 °F) therefore the impeller setting would be
0.71 mm (0.028 in.) off the casing. This value however
needs to be adjusted by 0.05 mm (0.002 in.) to
compensate for the movement associated with
tightening the set screws on the bearing carrier. This is
accomplished by subtracting 0.05 mm (0.002 in.) from
the desired impeller setting value of 0.71 mm (0.028 in.).
As a result, the bearing carrier would need to be moved
axially 0.64 mm (0.025 in.). First, turn the bearing
carrier clockwise until the impeller comes into light
rubbing contact with the casing. To determine the
number of indicator patterns that you will need to rotate
the carrier, divide 0.10 (0.004) into the desired setting;
0.71
⎟ 0.10 = 7.1 (.028 ⎟ 0.004 = 7). Rotate the bearing
carrier counter-clockwise 7 indicator patterns which will
give a clearance of 0.70 mm (0.028 in.). Flowserve
suggests that a felt tip pen be used to mark an initial
reference point on the bearing housing and the bearing
carrier. A second mark should also be placed on the
bearing carrier 7 indicator patterns clockwise from the
initial reference point. Rotate the bearing carrier
counter-clockwise until the second mark on the bearing
carrier lines up with the initial reference point mark on
the bearing housing. Uniformly tighten the set screws
[6570.3] to lock the bearing carrier in place. The
impeller is now set.
The above procedure is fairly straightforward when
doing the final setting of the impeller. However, it can
be quite laborious when doing the preliminary setting in
order to establish the location of the mechanical seal.
For this reason, the following practice is recommended.
Before the pump is taken out of service, adjust the
impeller until it touches the casing and then rotate the
bearing carrier until the desired impeller clearance is
obtained. Identify this location on the bearing carrier
and then rotate the bearing carrier until the impeller
contacts the rear cover. Record the distance from the
desired impeller clearance setting to when the impeller
contacts the rear cover. The pump is now removed
from the casing and taken to the shop for maintenance.
When it is time to set the seal, the impeller is simply set
off the rear cover by the same distance recorded earlier.