valve set to bypass 1.05 mL/s one gallon per hour for each 760 mL/s 12 gpm
of rated cell capacity.
2.7.6.7
Drift Eliminators
Fabricate from fiberglass-reinforced polyester resin, mold-formed and power
pressed in multipass zigzag form. Support eliminator sections on
fiberglass tee sections supported by stainless steel clips embedded in fan
deck by 6.35 mm 1/4 inch brass rods. Free water carryover shall not exceed
0.05 percent of tower capacity.
2.7.6.8
Fans
Design fan assembly (fan and mounting) to give maximum fan efficiency and
long life when handling saturated air at high velocities. Provide fans
balanced by fan manufacturer either by individual blades or matched sets
and of multiblade design with a minimum of six aluminum, stainless steel,
or fiberglass blades. Fan hub shall be made of aluminum, ductile iron,
stainless steel, or fabricated steel (hot-dip galvanized after
fabrication), with adequate surface protection against corrosion. Tip
speed of blades shall not exceed 56 m/s 11,000 fpm to ensure maximum
quietness of operation. Where required by manufacturer or where needed for
critical applications to avoid structural transmission of machine noise,
provide hot-dipped, galvanized plates bolted and grouted to concrete deck
after alignment of fan motor and gear box, with galvanized or stainless
steel hold down bolts; or provide a unitized motor and gear support base of
structural steel with vibration isolation units. Speed reducer gears shall
be rated in accordance with AGMA using service factor of 2 for cooling
tower services. Gear reducers shall be spiral-bevel type for single
reduction and spiral-bevel and helical with parallel shaft for double
reduction. Drive shafts shall be stainless steel and shall be
full-floating type, fitted at each end with stainless-steel-plate type
flexible couplings.
2.8
COOLING TOWER WATER TREATMENT SYSTEMS
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NOTE: If the activity has a cooling water treatment
contract in effect, ensure that the system specified
is compatible with it.
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Capable of automatically feeding chemicals, and bleeding system water to
prevent scale, corrosion, and biological growths. Systems shall include
chemical feed pump, tank, bleed-off solenoid valve, electric impulse water
meter, electric timer, and conductivity controller. Provide a polyethylene
tank and injection valve assembly for each feed pump.
2.8.1
Feed Pumps
Positive displacement type with an adjustable capacity and discharge
pressure not less than 1.5 times the line pressure at the point of
connection. Provide with pressure relief valve, and check valve mounted in
the pump discharge.
2.8.2
Tanks
Construct of high density polyethylene, cylindrical in shape, and with a
hinged cover. Tanks shall have sufficient capacity to require recharging
SECTION 15601N
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