Furnish and install as shown on the plans an EVAPCO Model __________ induced draft counterflow cooling tower. Each unit shall have the capacity to cool __________ GPM (liters/sec) of water from __________ ºF (ºC) to __________ ºF (ºC) with a __________ ºF (ºC) entering wet bulb temperature.
Pan
The pan shall be constructed of G-235 (Z600-Europe) hot-dip galvanized steel for long life and durability. G-235 hot-dip galvanized steel designates an average coating thickness of 2.35 ounces of zinc per square foot (600 grams per square meter) on the steel. Standard pan accessories shall include overflow, drain, anti-vortexing hood, Type 304 Stainless Steel strainers, and brass make-up valve with plastic float. The entire pan area shall incorporate a stepped configuration for reduced water volume, lower operating weight and easier pan maintenance. The upper and lower pan bottoms shall be sloped to provide positive drainage of the complete basin section. Depressed side outlet sumps which are not an integral part of the basin shall not be acceptable.
Casing
The casing shall be constructed of G-235 (Z600-Europe) hot-dip galvanized steel. If Fiberglass Reinforced Polyester (FRP) side panels are acceptable, it must have a thickness of at least 0.093” (2,36 mm) and have a minimum density of 13 ounces per square foot (3960 grams per square meter) for long life and durability. The casing panels shall totally encase the sides of the fill section to protect the surface from direct atmospheric contact.
Models UBT 8-56B to 8-936B
Fan Motor(s)
__________ HP (kW) totally enclosed fan cooled (T.E.F.C.) ball bearing fan motor(s) with 1.15 service factor shall be furnished suitable for cooling tower service on __________ volts, __________ hertz, and __________ phase. Motor(s) shall be mounted on an adjustable base which is mounted on the side of the unit for service. A hinged protective cover shall shield the motor and sheave from the weather.
Drive
The fan drive shall be a multigroove, solid back V-belt type with taper lock sheaves designed for 150% of the motor nameplate horsepower. The belt material shall be neoprene reinforced with polyester cord and specifically designed for cooling tower service. A hinged protective cover shall shield the motor and sheave from the weather. Belt adjustment shall be accomplished from the exterior of the unit. Bearing lube lines shall be extended to the exterior of the unit for easy maintenance. All sheaves located in the airstream shall be constructed of aluminum alloy, vented guards shall not be acceptable. If internal belt adjustment is necessary, an internal working platform and ladder is required to access the drive system.
Models UBT 12-212B to UBT 24-936B
Fan Motor(s)
__________ HP (kW) totally enclosed air over (T.E.A.O.) ball bearing fan motor(s) with 1.15 service factor shall be furnished suitable for cooling tower service on __________ volts, __________ hertz, and __________ phase. Motor(s) shall be mounted on an adjustable base which allows the motor to swing to the outside of the unit for servicing.
Drive
The fan drive shall be a multigroove, solid back V-belt type with taper lock sheaves designed for 150% of the motor nameplate horsepower. The belt material shall be neoprene reinforced with polyester cord and specifically designed for cooling tower service. Fan and motor sheaves shall be aluminum alloy construction. Belt adjustment shall be accomplished from the exterior of the unit. Bearing lube lines shall be extended to the exterior of the unit for easy maintenance. All sheaves located in the airstream shall be constructed of aluminum alloy, vented guards shall not be acceptable. If internal belt adjustment is necessary, an internal working platform and ladder is required to access the drive system.
Axial Propeller Fans
Fans shall be heavy duty axial propeller type statically balanced. The fans shall be fabricated by the cooling tower manufacturer for single source responsibility and reliability. The fans shall be constructed of extruded aluminum alloy blades, installed in a closely fitted cowl with venturi air inlet for maximum fan efficiency. Each fan blade shall be individually adjustable. Fan cowl shall be covered with a heavy gauge hot dip galvanized wire fan guard.
Fan Shaft Bearings
Fan shaft bearings shall be heavy duty self-aligning ball type with self locking collars and grease fittings extended to the outside of the unit. Bearings shall be designed for a minimum L-10 life of 75,000 hours.
Fan Drive Warranty
Cooling tower fan drive components shall be covered by a five year manufacturer’s plan. Drive components protected by this warranty shall include the fans, bearings, fan shafts, belts, drive sheaves and fan motors.
Fill
The cooling tower fill shall be PVC (Polyvinyl Chloride) of crossfluted design for optimum heat transfer efficiency. The crossfluted sheets shall be bonded together for strength and durability. The fill shall be fabricated, formed and installed by the cooling tower manufacturer and shall be elevated a minimum of 4 feet (1,2 m) above the floor of the cold water basin to facilitate cleaning. The fill shall be suitable for use as a working platform. The PVC fill shall be self-extinguishing for fire resistance with a flame spread rating of 5 per ASTM E84-81a. It shall also be resistant to rot, decay and biological attack. The fill shall be able to withstand a water temperature of 130°F (54,4º C).
Water Distribution System
The unit shall be provided with a non-corrosive water distribution system which utilizes a single inlet connection for each cell. The spray header and branches shall be constructed of Schedule 40 polyvinyl chloride (PVC) pipe for corrosion resistance and shall have a steel connection which is either beveled for weld/grooved for a mechanical coupling to attach the external piping. The spray header and branches shall be removable for cleaning purposes to allow debris to be removed. The water shall be distributed over the fill by precision molded ABS spray nozzles with large 3/8 by 1 inch (9,5 mm by 25,4 mm) orifice openings and integral sludge ring to eliminate clogging. The nozzles shall be threaded into the water distribution piping to assure positive positioning. If open type gravity distribution pans are used, they shall be constructed with non-corrosive materials (FRP or stainless steel) and perimeter handrailing must be provided to allow safe servicing of the distribution pan.
Eliminators
The eliminators shall be constructed entirely of inert polyvinyl chloride (PVC) in easily handled sections and be completely separate from the fill section for maximum efficiency. The eliminator design shall incorporate three changes in air direction to assure removal of all entrained moisture from the discharge air stream. Maximum drift rate shall be less than 0.001% of the circulating water rate.
Air Inlet Louver Screens
The louvers screens shall be constructed of polyvinyl chloride (PVC) and mounted in easily removable frames on all four sides of the cooling tower for access to the entire basin area for maintenance. The louvers shall have a minimum of two changes in air direction to prevent splashout, block direct sunlight from entering the basin, and have a minimum 3/4” (19 mm) opening to prevent debris from entering the basin.
Finish
All pan and casing material shall be constructed of G-235 (Z600-Europe) heavy gauge mill hot-dip galvanized steel for maximum protection against corrosion. During fabrication, all panel edges shall be coated with a 95% pure zinc-rich compound.
Seismic
The equipment shall be designed and manufactured to withstand 1g horizontal acceleration concurrent with 0.3 g horizontal orthogonal and 0.5g vertical acting through the center of gravity. This design shall have been analyzed and certified by a licensed structural engineer, independent of the manufacturer. The anaylysis shall include the principle members and joints of the unit as well as the mounting configuration and hardware. The use of external anchorages, supports and bracing to meet the acceleration levels shall not be accepted. The unit will not be expected to maintain operation during the seismic event.
Windload
The equipment shall be designed and manufactured to withstand a force of 125 pounds per square foot applied at the center of pressure. The design shall have been analyzed and certified by a licensed structural engineer, independent of the manufacturer. The analysis shall include the principle members and joints of the unit as well as the mounting configuration and hardware. The use of external anchorages, supports and bracing to withstand the wind force will not be accepted. The unit will not be expected to maintain operation during the wind episode.
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