Flowserve Mark 3 Sealed Metallic Durco - Manual (Page 53)

MARK 3 USER INSTRUCTIONS ENGLISH 71569102 01-13
Page 53 of 72 flowserve.com
Power end 6.8.4.5
Assembled bearing housing, carrier, bearings, and
shaft.
Shaft/shaft sleeve run-out
Shaft run-out is the amount the shaft is “out of true”
when rotated in the pump. It is measured by
attaching a dial indicator to a stationary part of the
pump so that its contact point indicates the radial
movement of the shaft surface as the shaft is rotated
slowly. If a shaft sleeve is used then shaft sleeve
run-out must be checked. It is analogous to shaft
run-out. Measurement of shaft run-out/shaft sleeve
run-out will disclose any out of roundness of the
shaft, any eccentricity between the shaft and the
sleeve, any permanent bend in the shaft, and/or any
eccentricity in the way the shaft or bearings are
mounted in the bearing housing.
Shaft run-out can shorten the life of the bearings and
the mechanical seal. The following diagram shows
how to measure shaft/shaft sleeve run-out. Note that
both ends need to be checked. The run-out should
be 0.025 mm (0.001 in.) FIM or less.
Figure 6.21: Runout
Radial deflection - static
Radial movement of the shaft can be caused by a
loose fit between the shaft and the bearing and/or the
bearing and the housing. This movement is
measured by attempting to displace the shaft
vertically by applying an upward force of
approximately 4.5 kg (10 lb) to the impeller end of the
shaft. While applying this force, the movement of an
indicator is observed as shown in the following
diagram. The movement should be checked at a
point as near as possible to the location of the seal
faces. A movement of more than 0.05 mm (0.002 in.)
is not acceptable.
Figure 6.22 Deflection
Shaft endplay
The maximum amount of axial shaft movement, or
endplay, on a Durco pump should be 0.05 mm
(0.002 in.) and is measured as shown below.
Observe indicator movement while tapping the shaft
from each end in turn with a soft mallet. Shaft
endplay can cause several problems. It can cause
fretting or wear at the point of contact between the
shaft and the secondary sealing element. It can also
cause seal overloading or underloading and possibly
chipping of the seal faces. It can also cause the
faces to separate if significant axial vibration occurs.
Figure 6.23 Endplay
Seal chamber 6.8.4.6
Assembled power end and rear cover.
Face squareness to shaft
Also referred to as “Seal chamber face run-out.” This
run-out occurs when the seal chamber face is not
perpendicular to the shaft axis. This will cause the
gland to cock, which causes the stationary seat to be
cocked, which causes the seal to wobble. This run-
out should be less than 0.08 mm (0.003 in.) and
should be measured as shown below: