Practical Overview of A Cooling Tower Fan Blade

Here’s a clear and practical overview of cooling tower fan blades — types, materials, design features, performance considerations, and common troubleshooting.

What Is a Cooling Tower Fan Blade?

Cooling Tower Fan BladeCooling tower fan blades are large aerodynamic blades mounted on the fan hub to move large volumes of air upward through the tower. They create the airflow that drives evaporative cooling.

Types of Cooling Tower Fan Blades

1. Axial Cooling Tower Fan Blades (most common)

Used in almost all induced-draft and forced-draft towers.

* Long, narrow aerofoil blades

* High airflow, low static pressure

* Adjustable pitch

2. Propeller-Type Cooling Tower Fan Blade

Similar to axial but simpler; used in small package towers.

Cooling Tower Fan Blade Materials Used

1. FRP (Fiberglass Reinforced Plastic) – most common

* Corrosion-resistant

* Lightweight

* Good efficiency

* Used by Marley, Evapco, BAC, etc.

2. Aluminum

* Strong, lightweight

* Less corrosion-resistant vs FRP

* Used in older towers or special applications

3. PVC or ABS

* Lower cost

* Used in small cooling towers

* Not suitable for high temperatures

4. Carbon Fiber (premium)

* Very high strength

* Very low weight

* Used in critical industrial applications

Cooling Tower Fan Blade Key Design Features

1. Blade Pitch

Angle determines airflow and power draw.

* Adjustable pitch hubs are common.

* Incorrect pitch → high motor amps or low airflow.

2. Blade Twist & Aerofoil Shape

* Designed to maintain uniform lift across blade length

* Reduces turbulence & noise

* Improves efficiency

3. Hub Connection

* Taper-lock bushings

* Clamp mounts

* Bolted saddle mounts

Performance Specifications

Typical parameters include:

* Diameter: 3 ft to 40 ft (1–12 m)

* RPM: 90–250 RPM (large towers are low-speed)

* Airflow: 20,000–500,000+ CFM per fan

* Tip Speed: 6,000–12,000 ft/min

Cooling Tower Fan Blade Top Brands

* Marley (SPX)

* Evapco

* BAC

* Cofimco

* Howden

* Hudson Products

Cooling Tower Fan Blade Common Problems & Troubleshooting

1. Unbalanced Fan

Symptoms: vibration, noise.

Causes: blade damage, uneven weight, buildup.

2. Incorrect Blade Pitch

Symptoms: motor overload, low cooling performance.

3. Blade Cracks or Erosion

Caused by:

* Long-term UV exposure

* High-speed droplet impact

* Chemical corrosion

4. Loose Hardware

Can cause vibration and catastrophic failure.