UNIREX Pump - Manual (Page 49)

MARK 3 USER INSTRUCTIONS ENGLISH 71569102 08-06
Page 49 of 68 flowserve.com
Deflection
Shaft endplay
The maximum amount of axial shaft movement, or
endplay, on a Durco pump should be 0.03 mm
(0.001 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.
Endplay
6.8.4.6 Seal chamber
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:
Face squareness
Register concentricity
An eccentric seal chamber bore or gland register can
interfere with the piloting and centering of the seal
components and alter the hydraulic loading of the seal
faces, resulting in reduction of seal life and
performance. The seal chamber register concentricity
should be less than 0.13 mm (0.005 in.). The diagram
below shows how to measure this concentricity.
Concentricity
6.8.4.7 Installed pump
Complete pump installed.
Shaft movement caused by pipe strain
Pipe strain is any force put on the pump casing by the
piping. Pipe strain should be measured as shown
below. Install the indicators as shown before
attaching the piping to the pump. The suction and
discharge flanges should now be bolted to the piping
separately while continuously observing the
indicators. Indicator movement should not exceed
0.05 mm (0.002 in.).
Pipe strain movement
Alignment
Misalignment of the pump and motor shafts can
cause the following problems:
• Failure of the mechanical seal
• Failure of the motor and/or pump bearings
• Failure of the coupling
• Excessive vibration/noise
The schematics below show the technique for a
typical rim and face alignment using a dial indicator.
It is important that this alignment be done after the
flanges are loaded, and at typical operating
temperatures. If proper alignment cannot be
maintained a C-flange motor adapter and/or
stilt/spring mounting should be considered.
Alignment