How Long Can Your Plant Delay an Industrial Fan Rotor Replacement?

Procrastination is rarely beneficial in a manufacturing facility, and it can even be dangerous when it comes to a fan rotor replacement. 

In an environment where production demands and deadlines are always at the top of the priority list, anything that involves downtime or spending extra money usually takes a backseat. But the cost of procrastination can be high when it comes to caring for your industrial fans and the associated draft systems. 

In this post, Allen Ray, Vice President of ProcessBarron’s Air and Gas Handling Group, shares his expertise on how long your plant can delay an industrial fan rotor replacement and what options provide the best course of action. 

What’s at Risk If You Delay?

Safety is your biggest concern when delaying a fan rotor replacement. A failing fan poses a threat to employees and other equipment. The rotating assembly can disintegrate in an instant if compromised by wear or other structural issues such as cracking, potentially creating dangerous projectiles. We have seen pieces of disintegrated rotors pierce stacks or boiler tube walls, releasing high-pressured, superheated steam.  

Delaying a fan rotor replacement can result in a catastrophic failure and extensive downtime. When your fan is down, your plant is down, and emergency repairs are more expensive on forced outages than planned repairs. 

How to Extend the Life of Your Fan

Some companies run equipment far too long because of various reasons, including high sales and demand for products, an imminent sale of their plant, lack of funds for proper maintenance, plus a number of other reasons.   If you’re concerned about long-term value and business sustainability, that approach is regressive and does not work. 

The fan may need to be replaced, but oftentimes a worn-out fan rotor is more of a symptom and not the cause.  It may mean that the mechanical or cyclone dust collectors that collect the heavy wearing particles out of the gas stream — and hence minimize damage to fan blades — are compromised. There are normally upgrades available to the wear protection of a rotor, such as different wear pad materials or a modified design that could improve wear life.   Also, we have techniques today that alter rotor geometry using CFD modeling as a method to guide the heavy wearing particles (10 to 15 microns) through the fan without touching the blades. 

Measure and Maintain

You have to consider everything related to your fan to ensure reliability and avoid catastrophic issues like one a customer experienced a year ago. In the middle of the cold winter night, the plant maintenance manager called us to request an emergency repair or replacement for a fan that had a catastrophic failure. The ID fan had some moderate wear on it year to year and was being addressed by weld build-up and wear pad replacement. The maintenance group diligently tracked wear on the blades and could predict when they needed to do repairs or replacements. What they failed to do was track the wear on the centerplate of its large rotor.  

This cold night, the operators noticed they lost draft from the fan, and the motor amperage dropped to almost nothing. They dispatched a maintenance group to check on the fan and found the fan running but discovered that although the fan motor was still running, the only things left to spin was a partial of the centerplate, the hub, and the shaft. The centerplate had failed just beyond the hub flange, and the rest of the rotor had sheared away. The failing rotor exploded and breached the housing and scattered shrapnel all out in front of the fan. The plant personnel were shocked to see the remnants of the fan rotor running with no blades. They felt they had been doing a great job measuring, trending, and maintaining the blades to combat  their wear issue. However, where they failed was they ignored the centerplate, and over time, it thinned from erosion similar to that which was happening to the blades. Eventually, this thinned centerplate ruptured as a result of normal centrifugal forces failing catastrophically.   

Measure, document, and trend all aspects of your fan and air handling system. This data can alert you to problems before they endanger your equipment or your employees giving you time to react in a controlled manner.  Doing a program such as this will allow you to plan a repair or replacement in a planned outage period and not have to react in an emergency when a fan fails.  Also, if you detect and address problems early, you can often achieve the desired results with repairs instead of complete fan rotor replacement. 

How Do You Know It’s Time to Replace a Fan Rotor?

It’s not always easy to tell when repairs will suffice or when purchasing a fan rotor is the most strategic decision for your facility. As much as we’d like to offer a rule of thumb, the demands on every fan are different. You can watch for things like energy consumption that doesn’t align with output, changes in vibration patterns, unusual bearing problems, etc. But ultimately, a thorough inspection by an experienced professional may be required. 

But we do have some good news. First of all, once you’ve had your fan inspected, you are equipped with information to prioritize projects relative to other needs in your facility instead of flying blind. And if a fan replacement is recommended, a new fan can often pay for itself in 2 years or less. 

Our field service specialists can perform emergency equipment repairs and equipment assessments on-site. Contact your rep and ask about our “Inspect, Advise & Quote” program. We can determine if your fan can be repaired or if a replacement is needed. It may be that the existing rotor design can be upgraded to provide a more efficient design as well as a greater wear life.