Cooling Tower Safety: Don't Do It Yourself
Most people think of cooling towers as large chimney-like structures outside nuclear power plants. But you'll find cooling towers at hospitals, shopping malls, or factories. And these towers do not look or operate like the stereotypical structure.
Cooling towers keep a building's inhabitants safe and healthy. But the large fans inside towers can be dangerous for workers who oversee and maintain them.
Cooling Tower Basics
Cooling towers are a necessary component of industrial facilities and other large buildings. They use large fans to chill water for air conditioning, power generation and other processes. The fan moves air over the water, changing its temperature before distribution.
Most facilities add cooling towers just as provided by the manufacturers. A typical setup includes the fan, an enclosure, a gearbox, and a motor. The motor generates power to turn the large fans. But a fan doesn’t need a motor to turn; wind or draft from other rotating fans will get cooling tower fans spinning. Even from a slow start, fans can spin up to full speed without the motor on.
When workers have to go near or enter the tower, the spinning fan (or even the possibility of a fan that can get up to speed) is a hazard.
Tower cells don’t provide much space to get around the fan. Inside a tower, workers are often right up against the fan. When a fan with a 12-to-35-foot diameter starts to spin, there’s a lot of power behind it. And even when the motor is locked and tagged out, the fan can still drift.
Stopping a Spinning Fan
Considering that the fan in a cooling tower can spin on its own without power, it’s important to make sure that doesn’t happen when workers need to enter the structure. Cooling tower fans don't come with an out of the box solution to stop a spinning fan or to keep one from moving in the first place.
Placing a two-by-four up against the motor shaft in an attempt to keep the fan from spinning.
In the past, fan owners adopted many do-it-yourself methods for slowing a spinning fan or to stop one from spinning on its own. Some people have used their hands to try and stop the blade from spinning. Others have used ropes to lasso the blades. And some include placing shoes or two-by-fours up against the motor shaft to stop it.
Some operators try other methods, like a rope, to stop a fan from starting to spin.
But just as you wouldn’t use any of these solutions on a ceiling fan at home, this type of approach should not be taken with a large industrial fan. The simple reason is these so-called solutions are not safe. They might stop a fan or keep it from moving temporarily, but they’re not permanent solutions and rely on the strength of the object used to stop a fan.
Applying Vehicle Technology to Cooling Tower Fans
Shortly after Hurricane Katrina hit the southeastern United States in 2005, an industry-wide solution to stopping unwanted fan motion became necessary. Hurricane-force winds and other severe weather that followed were dangerous to workers who had to carry out maintenance on cooling towers in affected areas. The best solution, realized by engineers at Regal Rexnord, was a brake, like one you would find in a car, connected to the drive shaft. Brakes not only stop potential energy, but also keep that potential energy from spinning up when locked.
Considering the situation, solutions needed a brake located outside the fan shroud. Using this location for a brake would not need workers to get into the path of the fan blades to stop it. Additionally, the brake would be easy to activate. Workers could actuate the brake mechanically, squeezing brake pads together on a rotor connected to the drive shaft. Within 15 seconds, the brake could bring a fan from full speed to a stop, as well as allow users to lock the fan in place.
Addax: The Cooling Tower Fan Brake Industry Leader
The industry leader in cooling tower fan brakes is the Addax from Regal Rexnord. Regal Rexnord’s power transmission solutions are used in cooling towers around the world. The Addax brake is a mechanical, manually-actuated caliper disc brake. Addax stops, holds and locks out cooling tower fans.
Workers can activate the Addax brake in seconds during maintenance activities or in the event of a facility lockdown. The addax brake stops and locks cooling tower fans in a matter of seconds. The Addax is made of corrosion-resistant, 316 stainless steel. This solid construction leads to less maintenance and more uptime.
Considering that very cooling tower coupling installation has unique dimensions, Regal Rexnord makes every Addax coupling assembly to order based on customer-supplied specifications.
Talk to one of our expert sales professionals about how our solutions can efficiently power your business.