IM-995
Installation, Operation & Maintenance Manual
18
Optional Accessories
1. Turning Gear — A turning gear is sometimes used in high temperature applications where the fan is exposed to high temperature
gases when not in operation. The impeller and shaft can expand unevenly due to the temperature when sitting idle, which can
cause vibration at startup and/or a permanent set to the rotor. The turning gear slowly turns the fan from the outboard side
while it is not operating, providing for even thermal expansion. It starts automatically when the fan shuts down and disengages
2. Shaft Seals — The standard shaft seal is a wire inserted fiberglass
tacky cloth element retained with an aluminum retaining plate and
clips. Other configurations of shaft seals are available for special
applications, such as when it is necessary to keep the shaft seal as
gas tight as possible. Shaft seal application manuals are provided in
Fan Engineering FE-700 available on www.tcf.com. Other seals such
as stuffing boxes, mechanical seals and carbon ring seals need special
attention. It is imperative that after the fan has been leveled, shimmed,
fastened to the foundation and ducted the shaft and seal be checked
for concentricity and angularity. The seal must not bind when the shaft
is rotated. Stuffing box packing material must not be compressed too
period of time. Connect a purge if specified. Carbon ring seals have pins
that prevent ring rotation.
3. Variable Inlet Vanes — Variable inlet vanes are provided as assemblies
internally in the inlet cone or externally in a flanged cylinder. The
vanes are used to control volume and save power in installations
where different volumetric operating conditions are used. Installation
manuals are provided in other engineering supplements for specific fan
types. Variable inlet vanes may be provided with powered operators in
which case the manufacturer’s installation and operating manuals will
be provided. Inlet vanes are unidirectional. Vanes should be stroked
periodically to prevent binding and possible seizure. Note: The weight
of customer supplied vanes may need to be supported indepently of the
fan. Consult with Twin City Fan.
4. Inlet Box and Inlet Box Dampers — Inlet boxes may be provided to
allow transition from a duct to the fan inlet. Inlet box dampers may also
are usually provided as a complete assembly and are installed with
the damper axles parallel to the fan shaft. They should be installed
if the fan is operated regularly with damper settings less than 30%
open. Operation below 30% should be limited to start-up or occasional
periods of low duration.
Orientation of Damper Blades Relative to Fan Rotation
Orientation of Inlet Vanes Relative to Fan Rotation
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