Cooling Tower
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Performance And Guarantee Of The Cooling Towers
The Cooling Tower shall be guaranteed to perform in accordance with the conditions specified. The Contractor shall provide performance curves, with appropriate correction factor charts to substantiate the towers' capacity. The Contractor shall specify the amount of make up water required, with detailed information on evaporation loss, carry over loss. The tower shall be installed and certified as correctly installed by the factory appointed representative. All moving parts shall be guaranteed for three (3) years.
Square Type Cross Flow Towers
The Cooling Towers shall be induced draft vertical discharge double flow Cooling Tower. The main components and accessories shall be to the following specifications:
i) Collection Basin
The water basin shall be of 12 gauge thick steel plate, dip galvanised. It shall be made rust resistant and corrosion proof by suitable means. The basin shall be self cleaning with sump, clean-out and drain fittings; overflow and float operated make up valve. All other steel components such as Post, Beams, Ladder etc., shall be all hot dipped, galvanised treated and finished with oil paint to prevent rust and corrosion.
ii) Air Inlet Louvres
The inlet louvres shall be waveform, fibreglass reinforced polyester (FRP) spaced to minimise air resistance and prevent water splash on.
iii) Water Distribution System
The Hot Water Distribution basin shall be open gravity type with suitable corrosion protection system. Distribution weirs and plastic metering orifices shall be provided to assure an even distribution of water over the entire deck.
iv) Fill Wet Deck Surface
The wet deck surface or fill shall be formed from Polyvinyl Chloride. It shall be Fire resistant and rigid and not collapse due to the weight imposed on it. They shall be impervious to rot, decay and fungus or biological attack.
v) Drift Eliminator
The drift eliminators shall be of formed PVC which is fire resistant. It shall limit drift loss to 0.005% or less of the circulating water flow rate.
vi) Mechanical Equipment
Fan(s) shall be fixed pitch, heavy duty cast aluminium axial flow with a minimum of eight blades. It shall discharge through a fan cylinder designed for streamlined entry and minimum tip clearances for maximum fan efficiency. The fan and shaft shall be supported by heavy duty, re-lubricable ball bearings with special moisture-proof seals, grease packed, self aligning and integral slinger rings. All bearings shall be designed for minimum life of 40,000 hours. The fans shall be coupled to motor through reducing gears (which is preferred) or by one piece multi-groove neoprene/polyester belt designed specifically for cooling tower service. The fan sheave and motor sheave shall be protected from moist discharge air. The fan motor shall be totally enclosed, air-over (TEAO) 1800 RPM reversible squirrel cage, ball bearing type, designed specially for Cooling Tower service. The motor shall be furnished with special moisture protection on winding shafts and bearings.
vii) Access and Safety
Access doors shall be provided at both end walls of the tower for access to eliminators and fan plenum chamber. A heavy gauge hot dip galvanised wire fan guard shall be provided over each cylinder.
viii) Finish
All steel panels and structural elements shall be made from G210 hot dip galvanised steel, with edges given a protective coat of zinc rich compound. In addition a Zinc Chromatized Aluminium finish shall be applied to the exterior of the units after assembly.
ix) Flow Balancing Valves
Factory installed, adjustable flow balancing valves shall be furnished as standard in each hot water basin for balancing the flow rate to each basin.
x) Strainer
A strainer assembly of anti-vortex design shall be provided as standard on all units. Large area lift out strainer screens shall be provided to avoid the need for frequent servicing. When cleaning is required the perforated strainer surface shall be easily washed clean. The anti-vortex baffle shall be specifically designed to specifically prevent air entrancement.
xi) Assembly
The unit shall be factory assembled fully and sent to site in a fully assembled condition with lifting devices located suitably at the bottom and tap of the units.
Water Treatment Equipment & Accessories
All the Cooling Towers shall be provided with an approved type of water treatment system. The Tenderer shall submit along with the tender full details of all equipment chemicals, controls and monitoring devices. The system should consist of a automatic dosing and metering pump operated by a pH meter which will monitor the water condition. The dosing chemical used shall be liquid type. To prevent scale and deposits building up in the tower automatic bleed off system with automatic valves etc., shall be provided.
Noise
The Cooling Tower shall have low noise characteristics and shall achieve the noise level criteria.