MK Plastics AXTC Centrifugal Inline Fan IO&M - Manual (Page 3)

Duct Connections
To reduce possible vibration transmission through the
ductwork, M.K. Plastics recommends the use of flexible
connectors instead of a rigid duct connection (e.g. flange-
to-flange connection). Companion flanges are standard
accessories for flexible connection.
Wheel-Inlet Overlap
Efficient performance is achieved by having the correct wheel
to inlet overlap and uniform radial gap. This should always be
verified before initial start-up and if possible after the fan has
been in operation for 24 hours.
The overlap is adjusted by loosening the wheel hub on the
shaft and moving the wheel to the correct position - refer to
Table 1. for values. A uniform radial gap (between the edge of
wheel inlet and edge of inlet cone) is achieved by loosening
the bolts on the inlet cone and centering it on the wheel. In
both cases, a trim balance maybe required.
Drive Maintenance and Installation
V-belt drives need periodic inspection, retensioning, and
occasional belt replacement. When inspecting drives, look for
dirt buildup, burrs or obstructions that can cause premature
belt or drive replacement. If burrs are found, use fine emery
cloth or a stone to remove them. Be careful that dust does not
enter the bearings.
M.K. Plastics Corp. Montréal, Québec www.mkplastics.com Page. 3
Ducted Installations
Efficient fan performance relies on the proper installation
of inlet and discharge ducts. Installations with poor inlet or
discharge configurations may result in reduced performance.
Make sure the following recommendations are followed.
Non-Ducted Inlet
If the AXTC has an open inlet (no duct work) that is too close
to a wall or bulkhead, this may cause performance problems.
The fan needs to have a minimum of two effective wheel
diameters away from inlet to the wall.
Free Discharge
If possible, avoid a free discharge into a plenum which could
result in lost efficiency because the effect of discharge static
regain is not allowed.
Inlet Duct Turns
Installation of a duct turn or elbow too close to the fan inlet
reduces fan performance. To achieve full fan performance,
there should be at least two effective wheel diameters
between duct turns or elbows and the fan inlet.
Discharge Duct Turns
Where possible, allow minimum two duct diameters between
duct turns or elbows and fan outlet.
Min.
2 x Dia.
Turning Vanes
Min.
2 x Dia.
Min.
2 x Dia.
Figure 4. - Open Inlet
Min.
2 x Dia.
Turning Vanes
Min.
2 x Dia.
Min.
2 x Dia.
Figure 5.
Free Discharge
Min.
2 x Dia.
Turning Vanes
Min.
2 x Dia.
Min.
2 x Dia.
Good Poor
Figure 6 - Inlet Ducting
Min.
2 x Dia.
Turning Vanes
Min.
2 x Dia.
Min.
2 x Dia.
Good Poor
Figure 7 - Discharge Ducting
Size
Overlap
[inches]
1825 0.75
2225 0.94
2450 1.00
2700 1.06
3000 1.31
3300 1.38
3650 1.50
4025 1.63
4450 1.81
4900 2.00
5425 2.13
6000 2.38 Overlap
Figure 9.
Wheel/Inlet Overlap
Table 1.
Wheel/Inlet Overlap
Inlet Flexible
Connector
Inlet Companion
Flange
Outlet Flexible
Connector
Outlet Companion
Flange
Inlet
Duct
Outlet
Duct
Figure 8. - Inlet/Outlet Flexible Duct Connection