MK Plastics DHK-NW IO&M User Manual
Bulletin 40-02-June 2013
REVISIONS
REV.
DESCRIPTION
Revision DATE
APPROVED
ZONE
E.C.O. No:
REVISED
ALL
0
EMISSION
N.A.
04/27/09
LIU
CORPORATION
SERVING THE NEEDS OF MODERN INDUSTRY
INSTALLATION, OPERATION AND MAINTENANCE MANUAL
Introduction
This bulletin contains the proper installation, operation and
maintenance procedures for the standard DHK & DHK-NW
Medium to High Pressure Centrifugal Fiberglass Fan, to
ensure safe and trouble-free fan operation.
The M.K. Plastics catalog on the above corrosion resistant
FRP fan, provides additional information describing the
equipment, fan performance, available accessories, and
specications.
For additional safety information, refer to AMCA publication
410-96, Safety Practices for Users and Installers of Industrial
and Commercial Fans.
For Information on special fan application requirements,
contact M.K. Plastics corporate ofce at (514) 871-9999.
DHK & DHK-NW
Centrifugal Fiberglass Fan
Handling
Fans are to be hoisted and moved by the lifting lugs provided
on the fan (see Figure 1). Location of lugs & brackets varies
by fan size and arrangement. Fans can also be hoisted with
slings placed around the fan housing. When a single hoist
is used, a “spreader” will keep the sling from slipping on the
housing. Large units may have lifting lugs or holes which
should be used only to stabilize the unit while using a sling to
support the weight.
Chain or wire slings should be well-padded where they
contact the fan as not to cause damage to the berglass
surface. Fans should never be lifted by the shaft, fan
housing, motor, belt guard, damper, weather hood, inlet &
outlet anges or any other accessories.
Lifting Lugs
Receiving and Inspection
All M.K. Plastics fans are carefully inspected before leaving
the factory. Compare all components with the bill of lading or
packing list to verify that the proper unit was received. Check
each unit for any damage that may have occurred in transit.
Mishandled units can void the warranty provisions. If units
are damaged in transit, it is the responsibility of the receiver
to make all claims against the carrier. M.K. Plastics is not
responsible for damages incurred during shipment.
WARNING
This unit has rotating parts. Safety precautions
should be exercised at all times during installation,
operation, and maintenance.
ALWAYS disconnect power prior to working on fan.
Lifting Lugs
Lifting Lugs
Figure 1.
Lifting Using the Lifting Lugs
Storage
If the unit cannot be installed and operated immediately,
precautions need to be taken to prevent deterioration of the
unit during storage. The user assumes responsibility of the
fan and accessories while in storage. M.K. Plastics will not be
responsible for damage during storage.
Store in a dry, protected area being sure fan shaft, bearings
and impeller are protected against dust and corrosion. If it
is necessary to store outdoors or within a building under
construction, special care must be taken to prevent moisture,
dirt or dust accumulation. Coat the shaft with grease or rust
preventative compound. Cover and seal bearings to prevent
entrance of contaminants. Impeller should be rotated at least
once a month to circulate the grease in bearings. If stored
outdoors, cover completely with a tarp or heavy plastic wrap.
Electrical connections and leads must be protected from
moisture. Block impeller to prevent natural rotation. Do not
allow material of any kind to be piled on top or inside of fan.
M.K. Plastics Corp. Montréal, Québec www.mkplastics.com Page. 1
Pre-Installation
When the unit is removed from storage after a long duration,
all bearing grease should be purged and replenished with
fresh grease as per the lubrication decal. The motor should be
measured to verify that the resistance is still at a satisfactory
level compared to the value recorded prior to storage.
Inlet & Outlet Fan Installation
Efcient fan performance relies on the proper installation
of inlet and discharge ducts. Installations with poor inlet or
discharge congurations may result in reduced performance.
Restricted or unstable ow at the fan inlet can cause pre
rotation of incoming air or uneven loading of the fan wheel
resulting in increased system losses and sound levels.
Free discharge or turbulent ow in the discharge ductwork
will also result in system losses. Make sure the following
recommendations are followed.
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 three effective wheel diameters
between duct turns or elbows and the fan inlet.
Poor
Discharge Duct Turns
Where possible, allow minimum three duct diameters between
turns or elbows and fan outlet. Fan performance is reduced
when turns are made immediately off the fan discharge.
Poor
Good
Min.
3 x Dia.
Turning Vanes
Figure 2 - Inlet Ducting
Good
Inlet Spin
A common cause of reduced fan performance is inlet spin. To
prevent this occurring, it is good practice to use turning vanes
in the duct to reduce the effects.
Good Poor
Figure 3 - Inlet Spin
Figure 4 - Outlet Ducting
Free Discharge
Avoid a free discharge into the plenum. This will result in
lost efciency because it doesn’t allow for a static regain.
Figure 5 - Free Discharge
Fan Installation
Follow proper handling instructions given earlier.
• Move the fan to the nal mounting position.
• Remove skid, crates, and packing materials carefully.
• If supplied, place vibration pads or isolation base on
mounting bolts. Line up holes in fan base with bolts.
• Place fan on mounting structure. Carefully level utilizing
shims as required at all mounting hole locations. Bolt
down the unit.
• Any grout may now be used. Bolt the fan in position
before applying grout. Do not depend upon grout to
support rotating equipment.
• Continue with Operations Checklist.
Additional instructions may be given for some fan sizes,
components and accessories in the submittal.
M.K. Plastics Corp. Montréal, Québec www.mkplastics.com Page. 2
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 oor 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 oor structure
supports should be per the structural engineer, in accordance
with load requirements and applicable building codes.
Isolation Base
Figure 5 - Isolation (Unitary) Base
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” deection)
• Floor Mounted Non-Restrained Housed Spring Isolators
(1” to 3” deection)
• 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.
Seismically Restrained
Spring Isolator
Housed Spring Isolator Rubber-In-Shear
Isolator
Figure 6
Vibration Isolators (Typical)
Wheel-Inlet Overlap
Efcient performance is achieved by having the correct wheel
to inlet overlap and uniform radial gap. This should always be
veried 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.
Size Overlap
1225 7/16”
Overlap
Figure 7
Wheel/Inlet Overlap
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”
Table 1
Wheel/Inlet Overlap
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 ne 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 rst 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 efciency 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
deection half-way between pulley centers is 1/60” for each
inch of belt span.
Deflection [inch]
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.
M.K. Plastics Corp. Montréal, Québec www.mkplastics.com Page. 3
Belt Span [inch]
Figure 8 - Belt Tension
Refer to the following procedure for belt tensioning -
C
1. Loosen motor plate adjustment bolts and move motor
plate in order that the belts can easily slip into the
grooves on the pulleys. Never pry, roll, or force the belts
over the rim of the pulley.
2. Adjust the motor plate until proper tension is reached.
For proper tension, a deection of approximately 1/60”
per inch of center distance should be obtained by rmly
pressing the belt. Refer to Figure 8.
3. Lock the motor plate adjustment nuts in place.
4. Ensure pulleys are properly aligned.
When replacing belts, replace the entire set. After initial
replacement and tensioning, recheck belt tension after a few
days. New belts require a break-in period. Never use belt
dressing on any belts.
Drive Alignment
Pulley alignment is adjusted by loosening the motor pulley
setscrew and by moving the motor pulley on the motor shaft.
Fig. 9 illustrates correct and incorrect pulley alignment.
Correct Incorrect
Wheel and Shaft Maintenance
Periodically inspect the shaft and wheel for dirt buildup,
corrosion, and signs of excess stress or fatigue. Clean the
components. If the wheel is removed for any reason, make
sure that it is securely attached to the shaft before restarting
the fan.
Arrangement 8 Shaft Flexible Couplings
Coupling alignment should be checked after installation and
prior to start up. Alignment is set at the factory, but shipping,
handling, and installation can cause misalignment. Check
for misalignment between the coupling halves. Parallel
and angular misalignment and separation gap are shown
in Figure 11. Refer to coupling manufacturer’s installation
instructions for allowable misalignment and separation gap
tolerances. When correcting for misalignment using shims,
the shims should only be located under the motor. Do not
place shims under the shaft bearings. A dial indicator or
laser can be used for alignment where greater precision is
required. After aligning procedure, check for tightness of all
coupling component pieces and ensure that they are clean
from dirt and debris.
Separation
Incorrect Incorrect
Figure 9 - Pulley Alignment
A recommended method of inspecting
the pulley alignment is shown in
Figure 10. With the shorter leg of a
carpenter’s square or other straight
edge lying along the case of the
motor, adjust the position of the motor
pulley (or the motor) until the longer
leg of the square is parallel to the belt.
Motor Maintenance
The three basic rules of motor
maintenance are:
Figure 10
1. Keep the motor clean.
2. Keep the motor dry.
3. Keep the motor properly lubricated.
Blow dust off periodically (with low pressure air) to prevent
motor from overheating.
Some smaller motors are lubricated for life. Lubrication
requirements are normally attached to the motor. Use the
motor manufacturer’s recommendations for relubrication. If
this information is not available, the following schedule may
be used. Motors less than 10 HP running about eight hours a
day in a clean environment should be lubricated once every
ve years; motors 15 to 40 HP, every three years. For motors
in dusty or dirty environments or running 24 hours a day:
divide the service interval by 4. Do not over lubricate.
Angular
Misalignment
Parallel
Misalignment
Figure 11 - Flexible Couplings
Drainage Detail
All DHK fans come as standard with outlet drains due to the
possibility of water or condensation that may occur. Proper
disposal of water must occur by connection of drain outlet to
a drainage system (by others). Piping must have adequate
pitch for proper runoff and be supported (if needed) to prevent
the possibility of sagging and overow. The trap should be
lled before start-up.
A
Fan Drain
Dimension of A, B, C: Inches
Figure 12 - Drainage Detail
A: Must be greater than system static pressure.
B: Must be greater than 1/2 of the system static pressure.
C: 1” water seal.
B
M.K. Plastics Corp. Montréal, Québec www.mkplastics.com Page. 4
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