Flowserve Twin Screw Rotary - Manual (Page 25)

TWIN SCREW PUMPS. ORIGINAL USER INSTRUCTIONS. ENGLISH. 71569243 – 07/10
Page 22 of 53
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Parallel Alignment:
Mount the magnetic base on the pump half coupling hub
(either the face or the O/D as shown in the sketch) and
place the dial indicator button on the outside diameter of
the driver half coupling hub. (See Fig. 3). Note that the
length of extension rods should be kept at a minimum to
reduce deflection. Rotate the pump shaft and record the
dial reading at the top, bottom and each side. Correct
the parallel alignment by adding or removing shims
under the driver and/or moving the driver horizontally.
Repeat this procedure until the maximum total indicator
reading (T.I.R.) is within 0.076 mm (0.003 inch).
Figure 3
Angular Alignment:
With the magnetic base mounted on the pump half
coupling hub , move the dial indicator button to indicate
on the face of the driver half coupling hub as close to the
outside diameter as possible. (See Fig. 4). Turn both
shafts 360
° and record the dial readings at 90° intervals.
Adjust the shims under the motor as required and repeat
the procedure until the angular alignment is within 0.0005
mm (T.I.R.) per mm (0.0005 inch per inch) of maximum
hub diameter.
Figure 4
Repeat the checks on parallel and angular alignment,
ensuring the mounting bolts are secure, until the unit is
properly aligned. Note that correction in one direction
may affect the alignment in another direction. Re-check
the gap between the coupling hubs.
If any difficulty is encountered in achieving the
recommended alignment tolerances, the runout of the
pump and driver shafts and each coupling hub diameter
and face should be checked. Occasionally, due to
practical and unavoidable manufacturing tolerance build-
up associate with the pump, coupling and driver, it may
be necessary to match up the two coupling hubs in the
most advantageous relative angular position in order to
achieve an acceptable alignment.
Do not install the coupling spacer or sleeve until grouting
is complete and cured and the alignment is re-checked.
When the electric motor has sleeve bearings it is
necessary to ensure that the motor is aligned to run
on its magnetic centreline. A button (screwed into one
of the shaft ends) is normally fitted between the motor
and pump shaft ends to fix the axial position.
If the motor does not run in its
magnetic centre the resultant additional axial force
may overload the pump thrust bearing.
Complete piping as below and see sections 4.9
Final shaft alignment check up to and including
section
5 COMMISSIONING, START-UP,
OPERATION AND SHUTDOWN before connecting
driver and checking actual rotation.