Mechanical Equipment
You’ll receive a 5-year warranty against failure of any mechanical component in the fan drive system (except the motor, which is warranted by its manufacturer).
The Marley Geareducer speed reducers used in the Sigma line contribute a long record of dependability, long service life, and low maintenance to this assurance of reliability. Their designs meet or exceed the requirements of CTI STD-111 and AGMA Std. 420.04. We run-in every Geareducer unit under load prior to shipment to make sure that it will operate properly on your tower.
Housings are gray cast iron. Gears are high-strength, case hardened alloy steel. And all bearings are tapered roller bearings. A variety of available horsepower capacities and reduction ratios lets us choose the optimum Geareducer model and fan speed for your job. Service factors are always at least 2.0 as applied.
Splash-type lubrication and integral cooling fins preclude the need for maintenance-intensive oil pumps and coolers. A constant oil bath or flow lubricates every bearing in forward or reverse motion – at full or half speed.
All Marley Geareducer assemblies are right-angle type with motors located outside the tower’s saturated airstream.
A galvanized steel lube line runs from the Geareducer unit to a standpipe near the motor on each cell, so you can check oil level and change or add oil while standing on the fan deck.
All Sigma Series 1000/1200 towers offer the benefits of adjustable pitch propeller type Marley fans. The H-3 series fans normally used on smaller models incorporate cast aluminum blades and machined aluminum hubs. HP-7 series
/ Construction and Components /
fans, used on larger models, include hollow GRE (glass- reinforced epoxy) blades and epoxy-coated cast iron hubs. Blades on both fan types are adjustable in pitch, so you can take full advantage of rated horsepower or adjust the pitch to compensate for unusual job site restrictions. The true airfoil blades, designed specifically for cooling towers, offer efficient, quiet operation and long service life.
Fans operate inside structural GRP (glass-reinforced polyester) eased-inlet fan cylinders designed and applied to maximize fan performance. Cylinder height varies from 3'-5" to 7'-0", depending on fan diameter. Cylinders less than 6'-0" tall include galvanized welded fan guards. (See Access and Safety on page 7.)
Marley-manufactured driveshafts transmit power from the motor to the Geareducer assembly. All Marley driveshafts include 304 stainless steel tubes with welded- on stainless steel flanges and bonded neoprene flexible elements to transmit torque. Marley driveshafts are full- floating assemblies with non-lubricated flexible couplings on each end. Their tolerance to misalignment and torsional shock is unequalled in nonspecialized units. All Marley driveshafts are dynamically balanced at the factory to minimize operating vibrations.
Welded unitized hot-dip galvanized steel supports
maintain alignment throughout the mechanical equipment system. Marley torque-tubes provide superior strength and stability. Their cylindrical shape also keeps operating costs down by minimizing airflow restrictions and reducing air turbulence in the fan entrance region.
