Major Parts of a Cross Flow Cooling Tower
1. Structure and Casing
- Function: Provides the overall framework and support for all other components. It defines the tower’s shape and protects the internal parts from the environment.
- Description: Typically made of hot-dip galvanized steel (G235), stainless steel for corrosive environments, or fiber-reinforced plastic (FRP) for excellent corrosion resistance and light weight.
2. Cold Water Basin (Sump)
- Function: The reservoir at the very bottom of the tower that collects the cooled water after it has passed through the fill. It provides a suction reservoir for the pumps that recirculate the cold water back to the process.
- Key Features: Often includes a sump heater (for freeze protection in cold climates) and connections for make-up water (to replace evaporated water) and blow-down (to drain water and control mineral concentration).
3. Water Distribution System
This is a defining feature of cross flow design.
- Distribution Basins (Hot Water Basins): These are open, gravity-fed pans located at the very top of the tower, directly above the fill. They receive the hot incoming water from the process.
- Gravity Nozzles / Orifices: These are precisely sized holes in the bottom of the distribution basins. They rely on gravity, not pressure, to distribute water evenly in a sheet-like pattern over the fill material below. Their large size makes them resistant to clogging.
4. Fill (or Packing)
- Function: The “heart” of the cooling tower. It maximizes the contact surface area and time between the falling water and the flowing air, enabling efficient heat transfer through evaporation.
- Types: As discussed previously, it can be Splash Fill (breaking water into droplets), Film Fill (spreading water into a thin film), or Hybrid Fill (a combination of both).
5. Air Inlet Louvers
- Function: Located on the sides of the tower, directly opposite the fill. They serve two main purposes:
- To guide the ambient air horizontally into the tower and across the falling water.
- To prevent water from splashing out of the tower.
- Description: They are typically slanted to optimize airflow and minimize water carry-out.
6. Drift Eliminators
- Function: To capture and recover entrained water droplets from the exhaust air stream before it exits the tower. This minimizes water loss and prevents chemical treatment from being released into the environment.
- Location: Positioned at the top of the tower, after the fill and before the fan. They force the air to make sharp directional changes, causing the heavier water droplets to separate and fall back into the tower.
7. Fan and Drive Assembly
- Function: To move the massive volume of air horizontally through the fill and up and out of the tower.
- Components:
- Fan: Typically a large, low-speed, axial flow fan (like a propeller) located at the top of the tower. This is known as an Induced Draft configuration (fan pulls air through).
- Drive Shaft: Transmits power from the motor to the fan.
- Gearbox (Reducer): Steps down the motor’s high RPM to the optimal, lower RPM for the fan.
- Motor: The electric motor that provides the power. It is usually located outside the moist air stream to prevent damage.
8. Mechanical Equipment Support
- Fan Deck: The structural platform at the top of the tower that supports the fan, motor, and drive assembly.