Spencer Vacuum Cleaning Systems - Manual (Page 10)

VI. Four-Bearing
Overhung Machine
Instructions for Disassembly and Reassembly
Warning: Be sure all electrical power is disconnected prior
to performing Blower maintenance.
Caution: Parts must be reassembled in exactly the same
relative position. Therefore, it is recommended that each
part be tagged as it is removed from the machine to facilitate
later reassembly. It is especially important that the location
of each impeller, as well as its position on the shaft, be
marked.
When ordering replacement impellers and deflectors, refer
to notes on accompanying illustrations.
General Configuration
The four bearing unit employs the overhung impeller construc-
tion with the rotating element supported by a rigid ball bearing
bracket and shaft. The equipment is driven through a flexible
coupling.
Disassembly
1. Remove End Head Bolts (8) and End Head (11).
2. On other than keyed construction, mark the shaft (13) and
impeller (10) hub with an arbitrary 12 o’clock reference
point. Remove the first stage impeller (10A) and mark it for
reference during reassembly. On keyed construction, remove
snap ring. Remove impeller (10A) and its hub spacer and any
shims, marking them for replacement in their proper position.
3. Check axial position of each deflector (9) at four radial points
with reference to end of casing and record for reference
when reassembling unit.
4. Remove spacer (15) holding rope packing (18) in place.
Mark spacer for reference during reassembly.
5. Remove rope packing (18) holding deflector in place.
Remove deflector (9). Mark for reference during reassembly.
6. Proceed to remove remaining stages in the same way, mark-
ing each component to insure proper reassembly. Note:
Division Head (4) cannot be removed.
7. Rotate the Vacuum Producer shaft (13) so that the keyway is
in the 12 o’clock position. Mark the motor shaft and coupling
hub to show the corresponding 12 o’clock position. Remove
snap ring on Vacuum Producer side of coupling (1) and
slide coupling sleeve back.
8. Remove motor mounting bolts and slide motor (23) back.
Identify and secure individual motor shim packs under
each motor foot for reassembly.
9. Unbolt division head packing plate (6A) and slide packing
plate and packing (6) back on the shaft.
10. Mark the Blower end and coupling ends of the bracket (7)
for reference. Remove bearing bracket hold down bolts
and slide bracket/shaft assembly out of the casing.
11. Using heat and a puller, remove the coupling hub from the
shaft.
12. Unbolt the bearing caps and remove. These caps are NOT
identical so label the coupling end and blower end caps
clearly. Remove the bearings (5 & 5A) from the shaft.
Remove the shaft from the bracket.
Reassembly
1. Assemble the shaft (13) in the bracket with new bearings (5
& 5A) and grease. Assemble the caps, being careful to
insure the correct cap on each end.
2. Using heat, assemble the coupling hub on the shaft (13).
3. Place the division head packing plate (6A) and packing (6)
on the shaft. If for any reason the packing (6) is damaged,
replace it. Install the bracket/shaft assembly into the casing
in its original position. Be sure that the shaft is centered in
the casing. Assemble the packing (6) and packing plate
(6A) to the division head.
4. Move the motor (23) back into its original position. Insure
an adequate gap between the coupling hubs. Align the
motor (23) to the blower shaft (13) following the instructions
on page 4 of this manual.
5. Rotate the Vacuum Producer shaft to the 12 o’clock position
and align the corresponding mark on the motor coupling
hub. Recouple the motor (23) to the shaft (13) and run the
assembly to check for vibration. If excessive vibration is
present, check the shaft (13) for runout.
6. On keyed construction, the impellers (10), spacers and
shims are reassembled in precise reverse order of their
disassembly. Verify clearance at each stage. On other than
keyed construction, place the first impeller (10C) on the
shaft up against the division head (4). Mark the shaft (13)
approximately 1/8” behind the impeller and withdraw the
impeller to this point. This will insure a clearance of 1/8”
behind the impeller. Tighten the hub securely.
7. Inspect the interstage packing (14A), if applicable, on
deflector (9B) and replace if damaged.
8. Place deflector (9B) back tightly against the stops in the
casing. Install the rope packing (18) firmly into the groove,
using a suitable tool.
9. Install the next impeller (10B) on the shaft up against the
deflector (9B). Mark the shaft approximately 1/8” out and
withdraw the impeller to this point. Tighten the hub securely.
10. Install the spacer (15) into the casing. Make sure spacer
and deflector (9B) are pressed back tightly and at a uniform
distance from the end of the casing at four points.
11. Proceed in a like manner with remaining impellers, spacers
and deflectors.
12. Reassemble the end head (11) to the casing using a new
end head gasket (16).
Balancing
Each machine is fully tested before leaving the Spencer factory
to be sure vibrations, if any, are well within specifications for
that particular machine. However, rough handling during ship-
ment or improper disassembly/reassembly of a machine can
upset its balance and/or result in excess vibration.
If there is any excessive vibration due to an unbalanced condi-
tion after assembly, use the following procedure:
1. Check coupling for misalignment. If realignment does not
correct the vibration, rotate coupling hubs or machine shaft
and motor shaft 90˚ in continuous increments.
2. If vibration persists, shut the Blower down. Mark the position
of end impeller hub on the shaft. Loosen bolts or screws
securing the impeller. Rotate impeller 90˚ on shaft.
Retighten impeller. Run machine again at operating speed,
and check for vibration. Repeat this process until the best
position is located for impeller on shaft so that there is no
vibration in the machine.
Note: In case of trouble notify The Spencer Turbine Company,
Windsor, Connecticut, or the nearest Spencer representative,
describing in detail the nature of the difficulty before attempting
to disassemble the machine.
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