MK Plastics DHK-NW IO&M - Manual (Page 3)

M.K. Plastics Corp. Montréal, Québec www.mkplastics.com Page. 3
Isolation and Support Foundation
Essential to every DHK fan installation is a strong, level
foundation. A correctly designed concrete foundation with
a structural steel base or inertia base provides the best
means of supporting floor mounted units. Any foundation
size is determined by the fan arrangement, size, weight,
motor weight, position or fan orientation and location of the
installation. The weight of the foundation must be greater
than the weight of the fan and its motor. Roof or floor structure
supports should be per the structural engineer, in accordance
with load requirements and applicable building codes.
Vibration Isolators
To prevent vibration and noise from being transferred to
the building, vibration isolators are recommended. Isolators
should be located between the fan system and the support
structure. M.K. Plastics supplies three main types of isolators
for FRP fans:
• Floor Mounted Seismically Restrained Spring Isolators
(1” to 4” deflection)
• Floor Mounted Non-Restrained Housed Spring Isolators
(1” to 3” deflection)
• Floor Mounted Rubber-In-Shear Isolators (rubber
mounts)
Refer to the M.K. Plastics submittal for isolator installation
and adjustment instructions. In applications where seismic
installation is required, refer to the M.K. Plastics submittal for
further details.
After the fan, isolation base, and isolators are installed,
the entire assembly must be leveled. Position the level on
the isolation base, not the fan shaft, for proper leveling.
Additionally, the motor and fan shafts must be level and
parallel relative to each other for proper alignment.
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. Check sheaves for wear. Excessive
slippage of belts on sheaves can cause wear and vibration.
Replace worn sheaves with new ones. Carefully align
sheaves to avoid premature sheave failure.
Belt tension is determined by the sound the belts make
when the fan is first started. Belts will produce a loud squeal
which dissipates after the fan is operating at full capacity. If
the belt tension is too tight or too loose, lost efficiency and
possible damage can occur. The proper tension for operating
a V-belt is the lowest tension at which the belts will not slip
at peak load conditions. For initial tensioning, the proper belt
deflection half-way between pulley centers is 1/60” for each
inch of belt span.
Seismically Restrained
Spring Isolator
Housed Spring Isolator Rubber-In-Shear
Isolator
Figure 6
Vibration Isolators (Typical)
Size Overlap
1225 7/16”
1500 5/8”
1825 3/4”
2225 15/16”
2450 1”
2700 1-1/16”
3000 1-5/16”
3300 1-3/8”
3650 1-1/2”
4025 1-5/8”
4450 1-13/16”
4900 2”
5425 2-1/8”
6000 2-3/8”
Overlap
Figure 7
Wheel/Inlet Overlap
Table 1
Wheel/Inlet Overlap
Isolation Base
Figure 5 - Isolation (Unitary) Base
Deflection [inch]
Belt Span [inch]
Figure 8 - Belt Tension