If you work in the industrial sector, you need to know that conveyor belt fires are extremely common. Anytime you have a buildup of friction (which produces heat) and possible ignition sources, you have all the ingredients for a fire. One of the best ways to avoid fires in your workplace is to prevent conveyor belt rollers from overheating. Read on to learn how.
What Are Conveyor Belt Rollers?
There are many different types of conveyor belt systems. One of the most common is the roller belt conveyor. In a roller conveyor, a series of metal cylinders that look like rolling pins constantly turn and move things along the conveyor. A drive belt connected to a drive pulley powers the rollers, and there are return rollers underneath that help the belt come back to the pulley.
Depending on your conveyor belt’s length, you might have hundreds of rollers, counting both the bed rollers on top and the return rollers below. On the ends of every roller are ball bearings that help reduce friction and make the rollers turn quickly. Because they’re so important, the bearings are inside several layers of metal and plastic designed to keep things like dust out.
The Causes of Overheating
A roller belt may stop working properly if the ball bearings inside some of the rollers have failed. Bearings can fail for a number of reasons:
- Contamination (dust, dirt, etc.)
- Fatigue
- Misalignment
- Lubrication problems
- Corrosion
When the bearings fail, they lock up and prevent the roller from turning quickly, increasing the amount of friction. Friction produces heat, which other conditions can exacerbate. Extremely heavy loads, high rotation speeds, and weather conditions can all cause the amount of friction and heat to increase exponentially.
Heavy Loads
The reason why ball bearings are so important in roller conveyors is that they minimize friction. When two objects slide past one another, they incur friction over the entire surface area of contact. When two objects roll past each other, there isn’t as much contact, so the amount of friction is much lower.
When you have a heavy load on your belt, that adds more downward force than what your belt can handle. When that extreme downward force reaches a broken roller, it can produce enough friction to light a spark. Mechanically, it’s the same as lighting a match.
High-Speed Rotation
A roller belt that’s moving very quickly can also cause a fire. When your belt moves at high speed, the rollers generate more heat than usual. Higher ambient temperatures make fuel sources more receptive to ignition. According to some experts, fires can start when the temperatures are as low as 480 degrees Fahrenheit—that’s about the same as what you’d need to bake a pizza.
Weather Conditions
Both extreme heat and extreme cold can increase the chance of overheating. Hotter temperatures make ignition more likely, as explained above. On the other hand, cold temperatures can cause rubber to become brittle, changing the belt tension. Cold can also affect the viscosity of the lubricants inside your rollers, impeding bearing function.
What Happens When a Belt Overheats?
When a belt roller overheats, it can cause several problems. The first is malfunctioning. While overheating usually has a cause (like stalled bearings), it can also cause problems with bearings since the high temperature creates more mechanical stress. Having one roller not working properly can also add more stress to surrounding rollers, making it more likely for them to overheat too.
Fuel Sources
The second major problem with overheating is fire. Fire can break out whenever you have enough heat and fuel for ignition. In many industrial settings, the fuel comes from dust, dirt, and other particles that accumulate on the conveyor system.
How To Prevent Overheating
Visual inspections of belt rollers for overheating aren’t particularly effective. Overheated rollers don’t look much different from other rollers and may or may not turn normally. Instead of relying on employees to notice a bad roller, try some other strategies to prevent conveyor belt rollers from overheating.
Temperature and Vibration Sensors
Specially-designed sensors can tell you when the temperature of your rollers gets high enough to create a fire risk. They can also detect when your conveyor system is experiencing high vibrations, which super-heavy loads cause.
In a loud industrial setting, it can sometimes be difficult to hear when your machines are making more noise than usual. And unlike in Saturday morning cartoons, your rollers won’t glow red when they overheat. Sensors are some of the most accurate ways to know what’s actually going on with your belting system.
Clean Your Rollers
Buildups of dust, dirt, and debris can provide the perfect fuel for a fire. Cleaning your belt rollers regularly will help remove some of the ingredients for ignition. Cleaning the rollers will also lower the chance that particles get inside them and disrupt the bearings’ function. Bearings are incredibly sensitive, and even a small particle can impede their efficiency.
Cool Ambient Temperatures
Keeping the temperatures low (but not freezing!) around your belting system can help prevent ignition. Since high temperatures make starting a fire easier, keeping things cool will help diffuse the heat your belt rollers generate.
Proper Support and Tension
Belt rollers are most likely to fail either in their early life or as they start to wear out. Mistracking and misalignment are some of the most common early life problems. Sometimes, manufacturer defects cause them. Making sure your rollers have proper support and tension can prevent many early-life problems.
High-Temperature-Resistant Belting
Another solution to prevent overheating is to use drive belts resistant to high temperatures. Texas Belting and Supply carries many PVC conveyor belting styles with high temperature resistance and even flame-retardant coatings. The high temperature resistance makes overheating less likely, while the fire-retardant coatings keep fires from spreading if it breaks out.
Texas Belting and Supply carries hundreds of conveyor and automotive belts in every shape, size, and specification you can think of. We use dozens of protective coatings and high-quality rubbers and fibers. We also test our belts to ensure they hold up to the strictest OSHA standards. Call or email us today to get the highest-quality belting possible.
