Class 160 towers offer the benefits of adjustable pitch propeller type fans. All fans used on Class 160 towers include hollow GRE (glass-reinforced epoxy) blades and epoxy-coated cast iron or galvanized steel hubs. Blades are adjustable in pitch, so you can take full advantage of rated horsepower or adjust the pitch to compensate for unusual jobsite restrictions. The true airfoil blades, designed specifically for cooling towers, offer efficient, quiet operation and long service life.
Fans operate inside structural FRP (fiber-reinforced polyester) eased-inlet fan cylinders designed and applied to maximize fan performance. Standard cylinder heights are
6′-0″to 7′-0″, depending on fan diameter. 10′-0″cylinders are available as an option.
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 non-specialized 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.
■Water Distribution System
The gravity-flow water distribution system designed into the Class 160 tower essentially reduces pump head to its most basic component—static lift—saving you money on pump power. You won’t have to force water through internal piping and pressure spray nozzles, as you would in a counterflow tower.
Warm water enters the system through a Marley galvanized crossover pipe. Inlet connections for your piping are drilled to conform to Class 125 ANSI requirements. Marley flow-control valves balance the flow to both distribution basins of each cell. Water flows from the valves through a splash-suppression chamber and into the treated fir plywood distribution basins.
Polypropylene Marley “Spiral Target” nozzles in the basin
floor then distribute the water uniformly over the fill.
All materials in the water distribution system offer long life and minimal maintenance. Valves consist of cast iron bodies and grease-lubricated stainless steel operating stems. All plywood is treated exterior grade. The nozzles are chemically and biologically inert, so they’ll last indefinitely.
■Structure and Materials
Class 160 tower design conforms to the latest edition of the National Design Specification for Wood Construction (NDS) published by the National Forest Products Association, as well as CTI standards STD-114 and STD-103. Wind load criterion is normally 30 pounds per square foot of projected area and the design meets criteria for UBC Zone 1 seismic loading, based on a maximum water temperature of 120°F.
