SPX Cooling Technologies Marley Sigma Steel - Manual (Page 15)

Specifications Specification Value
Marley / Sigma Steel Cooling Tower / Specifications: Base
15
4.0 Fan Deck and Fan Cylinder:
4.1 The fan deck shall act as a working
platform for maintenance personnel. It
shall be fabricated of no less than 12
gauge steel, and shall be designed for
a uniform live load of 60 psf.
4.2 Fan cylinders shall be molded FRP.
They shall be through-bolted to the fan
deck structure to provide a consistent-
ly stable operating shroud for the fan.
5.0 Mechanical Equipment:
5.1 Fan(s) shall be propeller-type, incorpo-
rating heavy duty blades of cast alumi-
num or high strength, inert composite
material. Blades shall be individually
adjustable and replaceable. Fan(s) shall
be driven through a rightangle, indus-
trial-duty, oil-lubricated, geared speed
reducer. Speed reducers employing
pulleys and belts will not be accepted.
5.2 Motor(s) shall be ____ hp maximum,
TEFC, 1.15 service factor, and specially
insulated for cooling tower duty. Speed
and electrical characteristics shall be
1800 (1800/900) RPM, single winding,
___ phase, ___ hertz, ___ volts.
■ The indicated design values for framing and decking not only give you
assurance that the tower can withstand long term operation in a hostile
environment — but that it will accept many years of inspection and
maintenance traffic by your operating personnel.
■ Fiberglass-reinforced polyester fan cylinders provide the close tip clear-
ances and smooth airflow contour necessary for good fan performance.
The inert, noncorroding nature of FRP assures that these characteristics
will persist. Their 6' to 7' height also provides protection for operating
personnel.
■ Propeller-type fans require only half the operating HP of blower-type
fans.
They should be readily adjustable to permit compensation for job site
conditions that may tend to overload the motor. The fans of one manu-
facturer require the purchase of special positioners for each increment
of fan blade pitch.
Standard fan drives of other manufacturers may use V-belts.
Considering the size of fans involved — and the horsepower applied —
this is not good design practice. Geareducer ® drive is far more reliable
and trouble free, and is currently offered as an option by at least two
other cooling tower manufacturers.
■ Unless otherwise specified, motor speed will be 1800 RPM in 60 Hertz
areas and 1500 RPM in 50 Hertz areas. If you prefer the operating flex-
ibility of two-speed operation, please specify the RPM to be 1800/900
(1500/750 in 50 Hertz regions).