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. Using Figure 2 as a guide, assemble items 4 through 16 to the
inlet vane. Measure threaded linkage rod (item 6) to fit.
2. Center inlet vane in location of old vane or cone, and rotate
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
Figure 4, position quadrant (item 2 or 2A) to the housing side.
Weld quadrant to the housing frame (or housing side).
4. Drill a hole in the fan housing side to match the diameter of
control rod (item 3).
5. Reassemble bearing support frame and bolt it to fan housing
as shown in Figure 1.
6. Reassemble the bearing.
7. Repeat steps 1, 2, 4, 5 and 6 on the other side of the fan.
8. Remove blocking under the fan impeller and check to be sure
the impeller turns freely. Adjust bearing position or inlet vane
position as required. Tighten bearing fasteners.
9. Assemble the remaining parts of control system according to
Figure 2. Adjust position of connecting links as required to
enable both vanes to open/close smoothly and uniformly.
Threaded linkage rods (item 6) may have to be cut to required
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
