cleaning. Fill supports shall be wood or glass-reinforced polyester.
Supports shall have structural strength of not less than five times design
loading. Provide space supports as required to prevent sagging and
misalignment, and provide for an even mixing of air and water.
2.7.5.18
Water Distribution Systems
Design water distribution systems for each cell of each tower so that a
water flow of 140 percent of specified water flow will not cause
overflowing or splashing. Water distribution systems shall be accessible
and permit flexibility of operation. Distribution shall be open basin,
flume and troughs, or a pipe system with nozzles spaced for even
distribution, arranged so that flow to each cell can be regulated and
turned on or off independently. Provide separate regulation and stop
valves for complete balancing and complete shutoff from each cell. Systems
shall be self-draining and nonclogging. Spray nozzles, if used, shall be
cleanable; stainless steel, bronze, or high-impact plastic, nonclogging,
removable; and, spaced for even distribution. Provide removable covers of
same material and thickness as casing for entire water distribution basin.
Support covers by basin sides with top of cover flush with top of basin.
2.7.5.19
Piping
Provide inlet pipe to each cell with a bleed connection. Connections shall
have a regrinding globe valve set to pass 1.05 mL/s one gallon per hour for
each 760 mL/s 12 gallons per minute (gpm) of rated cell capacity. Piping
shall be installed under direct supervision of the tower manufacturer.
2.7.5.20
Drift Eliminators
Provide in tower outlet to limit drift loss to not over 0.2 percent of
specified water flow. Eliminators shall be constructed of not less than
10 mm 3/8 inch wood or polyvinyl chloride (PVC).
2.7.5.21
Fans
Provide each tower cell with one or more fans driven by electric motors,
dynamically balanced. Provide propeller fans with adjustable-pitch air
foil blades with a maximum tip speed of 56 m/s 11,000 feet per minute. Fan
blades shall be aluminum, stainless steel, or fiberglass.
2.7.5.22
Fan Stacks
Provide propeller fans with stacks of wood or fiberglass-reinforced
plastic. Minimum thicknesses of material shall be: Wood, 15 mm 1/2 inch
laminations reinforced at top and bottom; fiberglass-reinforced plastic, 4
mm 1/6 inch. Stacks shall be provided with a zinc-coated steel screen of
No. 12 gage wire and not over 13 mm 1/2 inch mesh secured to a frame of
zinc-coated steel.
2.7.5.23
Fan Drives
Mount fan on output shaft of a gear box with cut steel spiral, hypoid, or
other equally quiet and efficient gears. Bearings shall be ball or roller
type with a continuous oiling system with oil reservoir. Oil-level
indicators and oil filling and drain connections shall be provided outside
fan cylinder in an accessible location. If drain connection is below level
of fan deck, drain pipe shall be extended to outside of tower at an
accessible location. Rate gearing in accordance with AGMA 2005 and AGMA
SECTION 15601N
Page 35
Previous Page
