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The fan blades shall be of a hollow, light weight true
air-foil fiberglass-reinforced plastic (FRP) design
with variable chord width and twist to compensate for
the reduction in leading edge velocity from blade tip
to blade root. The construction shall consist of directionally
oriented fiberglass cloth and high temperature vinyl
ester resin. The blades shall be of a two parts construction
for maximum quality control of components. The parts
shall be bonded with an ultra high strength adhesive,
and secures by metal rives. (The track, lead and lag,
and twist of blade shall be computer controlled by robots
for exacting dimensional accuracy.)
The fan blades shall be protected
against erosion from water droplets or other solids
in the air stream byHudson's exclusive Tuf-EDGE @ process
that is incorporated in the construction of the blade
in the original molding process. This exclusive Tuf-EDGE
@ process insures there will be not a separation of
blade body and its protective coating during operation.
To ensure no foreign objects can enter the fan blade,
a molded rubber cap is installed over the connection
of the blade neck and blade body.
After assembly and computer
controlled balancing to a master standard, the blade
shall receive a polyurethane coating system designed
to provide ultra-violet ray protection. The blades are
then post cured at 320 oF to fully cure the
resin, adhesive, paint system and balance resin. Before
packing for shipment, each blade shall be again moment
balanced to verify all the processes have not changed
the exacting quality control requirements. The total
interchangeability of blades in the field is insured
by each blade receiving a computer generated label stating
its serial number, day of manufacture, type and final
balance moment.
The blades shall be assembled
in hubs fabricated from galvanized steel plates and
ductile iron hub spools. The hubs shall be bolted and
not welded to prevent heat warping. Blade clamps shall
be zinc rich coated gray iron, secured with galvanized
high strength bolts, lock washers and nuts, or 6063
extruded aluminum.
In order to insure maximum
efficiency, the fan assembly shall be supplied with
a fiberglass seal disc designed to prevent air recirculation.
Each seal disc will be balanced to insure smooth operation,
and each fan hub shall be dynamically or statically
balanced before the shipment. In summery above, Hudson's
standard materials are as follows:
- ● Blade : Fiberglass reinforced
vinyl ester
- ● Hub Spool : Ductile iron,
zinc rich coating
- ● Upper & Lower Plate
: Steel galvanized
- ● Blade Clamps : 6063 aluminum
as standard
cast iron as standard, epoxy coating
- ● Hub Fasteners : Grade
5 steel, Mechanical galvanized
- ● Seal Disc Fasteners :
18-8 stainless steel
Upon request, the hub spool
& plates could be coated with coal tar epoxy 5-7
mils (5/1000 - 7/1000 inch) dry film thickness in lieu
of galvanize and also the coal tar epoxy over galvanize
would be coated at cost.
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