Removing Old Cone or Vane
See Figure 2 for identification of all items referenced.
1. Shut off fan and lock out electrical power.
2. Remove belt guard and/or inlet screens.
3. Adjust motor position and remove belts and drive sheave.
4. Clean and remove rust from sections of fan shaft that extend
through the fan bearings. File smooth any burrs. Remove
bearing bolts and raise the shaft enough to take weight off the
bearing.
5. Working through fan outlet or through access door, block
under periphery of fan impeller so that fan housing supports
the fan impeller.
6a. For Fan With Setscrew Locking Collars — Loosen set screws in
bearing. Using wedges or pry bars, slide bearing off end of
shaft. If it is necessary to force bearing, use a brass rod to drive
against inner race of bearing only.
6b. For Fans With Split Type Bearing — Remove bearing cap,
bearing housing and bearing insert off end of shaft. If the
bearing insert must be removed by inexperienced personnel, it
is recommended that the bearing manufacturer be contacted
to provide instructions for dismounting.
7a. For Old Inlet Funnel Removal — Loosen fasteners that hold
inlet cone and bearing support frame to the housing side.
Remove old inlet cone and bearing support frame.
7b. For Pre-1981 Style Inlet Vane Removal — Remove hardware
from old vane, which attaches it to the housing side. Remove
control arm (or drive link). Loosen fasteners that hold inlet
cone and bearing support frame to fan housing side, then
remove old inlet vane and bearing support frame.
7c. For Post-1981 Style Inlet Vane Removal — Remove nut (item
16) and pull connecting arm out of the way. Loosen fasteners
that hold inlet vane and bearing support frame to the housing
side, then remove the inlet vane and bearing support frame.
8. Repeat steps 4, 6 and 7 on other side of the fan.
Assembling Nested Inlet Vane
1. UsingFigure2asaguide,assembleitems4through16tothe
inlet vane. Measure threaded linkage rod (item 6) to fit.
2. Centerinletvanein locationof oldvaneor cone,androtate
until inlet vane control ring is approximately in the same
position as shown in Figure 3. If old control linkage is being
reused, locate control ring clip so that connecting link can be
reattached. Be sure that when vane is partially closed the
entering air will be spun in the direction of impeller rotation.
3. For installation of new quadrant, using the dimensions in
Figure4,positionquadrant(item2or2A)tothehousingside.
Weldquadranttothehousingframe(orhousingside).
4. Drillahole inthefanhousingsidetomatchthediameterof
control rod (item 3).
5. Reassemblebearingsupportframeandboltittofanhousing
as shown in Figure 1.
6. Reassemblethebearing.
7. Repeatsteps1,2,4,5and6ontheothersideofthefan.
8. Removeblockingunderthefanimpellerandchecktobesure
the impeller turns freely. Adjust bearing position or inlet vane
positionasrequired.Tightenbearingfasteners.
9. Assembletheremainingpartsofcontrolsystemaccordingto
Figure 2. Adjust position of connecting links as required to
enable both vanes to open/close smoothly and uniformly.
Threadedlinkagerods(item6)mayhavetobecuttorequired
length.
10. Welded threaded linkage rod housing to hex nuts (item 14).
Spot weld the control rod to vane handle and control linkage
bar.
11. Reinstall the drive, guards, inlet screens, access door hardware,
etc.
Figure 1. BC, BAF DWDI Fan With Nested Inlet Vanes
©2004 – 2023 Twin City Fan Companies, Ltd.
IM-494
January 2023
Nested Inlet Vanes
BC, BAF DWDI
INSTALLATION, OPERATION & MAINTENANCE MANUAL
