Spencer Single-Stage Scroll Blowers - Manual (Page 6)

6
Instructions for Disassembly and Reassembly
Caution: Parts must be reassembled in exactly
the same relative positions. 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
impeller location and its position on the shaft be
marked.
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 shipment or
improper disassembly/reassembly of a machine can
upset its balance and result in excess vibration.
When a machine is being disassembled for repairs,
mark the parts as they are removed. If this is done,
no trouble should be expected from vibration when
they are reassembled in the same order.
However, if the impeller is being replaced or there is
any vibration due to an unbalanced condition after
assembly, use the following procedure.
Run the unit at maximum speed. Mark the position
of the impeller hub on the shaft. Loosen the bolts or
screws holding the impeller on the shaft. Rotate the
impeller 90˚ on the shaft. Run the machine again at
the maximum speed, and check the vibration.
Repeat this process until the best position is located
for the impeller on the shaft so that there is no
vibration or unbalance in the machine.
Disassembly
Scroll blowers are now being supplied with casing,
motor base and casing/base support welded into a
integral unit. This innovation provides a stable and
maintenance free platform. As a result, maintenance
is confined to removal of the motor on one end and
• Is the control panel energized?
• Have maintenance and operations personnel
been notified?
CAUTION: This blower must have adequate
system resistance at all times to avoid operation
at or near free delivery (wide open). It Is typically
imposed by the process and supplemented with
a throttling valve. Running the blower overloaded
will damage the motor.
Start Up
Caution: It is very important that the blower be
installed with regard to the correct direction of
rotation. A direction-of-rotation arrow is affixed
to the scroll casing.
Under no circumstances should the Scroll
Blower be operated without being connected to
the pipe system with which it is to be used.
When starting up a Scroll Blower it is
recommended that the blast gate or other control
device be closed. When first starting the installation,
an ammeter should be connected to the motor circuit
and the control device opened until full load current
is reached. At this point, the unit is delivering the full
rated volume of air for which it was designed and the
control device should be adjusted to prevent opening
beyond this point. (See following paragraphs.)
Multiple Machine Operation
Caution: All Scroll Blowers in a multiple machine
operation should be operated periodically. This
can be accomplished through bi-weekly,
alternate operation of the machines.
Check valves must be installed in the discharge of
each Scroll Blower to prevent blow-back through the
unit not in operation. These are available as optional
equipment.
When operating two or more Scroll Blowers in
parallel it is necessary to be sure that each machine
carries its respective share of the load. This is
accomplished by setting each blast gate so that the
Scroll Blower operates within the full load amp rating
of its motor. Once the proper setting is established,
tighten bolts securing the variable stop (View A) or
the locking nut (View B). This prevents the blast gate
from being opened beyond the full load rating of the
motor.
The Spencer Turbine Company ◆ 600 Day Hill Road, Windsor, CT 06095 ◆ TEL 800-232-4321 ◆ 860-688-8361 ◆ www.spencerturbine.com