Handling bulk materials is a complicated endeavor; one that is prone to costly mishaps if not handled expertly. Equipment operators must be knowledgeable to understand how each material will behave and the equipment must often be versatile to handle a wide variety of materials. Rubber belt conveyors are designed in a range of configurations to solve many of the issues that may arise in bulk material handling.
Challenges of Using Conveyors to Move Dry Bulk Solids
Particular challenges come when moving bulk solids up an incline. Rubber conveyor belting can be exceedingly useful in mitigating these difficulties. When moving bulk materials with a conveyor, there are three distinct problems that must be dealt with. The first, and possibly most challenging, is the fact that materials tend to fall backwards and off the edges of a conveyor when moving up an incline.
The second challenge comes when a conveyor is tasked with moving many different kinds of materials, as they often are. Materials have vastly different physical properties, and therefore behave differently when being moved upward on a conveyor. One small mistake in calculation could endanger the entire process. So conveyors need to be versatile.
Lastly, some bulk materials are highly corrosive to metal and/or toxic to workers and the environment, so containment is an important issue. Building an incline conveyor system that meets all of these challenges is a tall order. And we will see why rubber belting is used so often in moving bulk materials.
Rubber Belt Configurations that Solve These Problems
When transporting bulk materials, it's essential that you have conveyors and belting designed to adequately handle all of the aforementioned challenges and move the product at a fast enough rate to be economically viable, as efficiency is also an essential aspect of moving bulk materials.
Belts with flexible sidewalls work well in moving a product up steep inclines. Flexible sidewalls are designed to keep bulk materials from sliding off the sides of the belt when being moved at high speeds at angles of 45 degrees and higher. The flexibility of the rubber allows for sidewalls without seams so material can't work its way down into the conveyor mechanisms where it can corrode and cause other damage. High quality rubber and good belting design and construction ensure the belts won't wear prematurely.
While flexible sidewalls greatly help with containment, they don't prevent materials from falling backwards when the conveyor's angle of incline is higher than the materials angle of repose. This is where specialized cleats and nubs come in. Depending on the properties of the materials and the angles being used, a rubber belt can be fashioned with nubs of various heights or cleats that span the width of the conveyor belt. These wide cleats creates walled off sections that hold free flowing materials in place when moving upward. Nubs are basically vertical spikes placed at appropriate intervals along the belt that do an excellent job of keeping more sluggish materials from falling backward.
If you're unsure of which to use, cleats or nubs, you should understand that a full lengthwise cleat works particularly well with materials that have lower angles of repose, such as grain or cement, while others, like sand and asphalt, can be held in place on a belt with several high nubs. It's also important to keep in mind that, if you are looking to move materials up an extremely steep incline, say up to 90 degrees, the perfect configuration for such would be with sidewalls and substantial cleats that form a kind of bucket elevator.
It should be said that at lower angles of incline, there are many more options for conveyor belting that will properly contain a wide variety of materials. Trough belts are simple and very useful at lower angles. Trough belts are different from typical flat belts because they utilize a unique concave design to create a "trough" to hold materials with the help of specialized rollers along the conveyor path. Trough belts are ideal for high volume and high speed material movement. They do not work well with an incline degree of more than 25, as the concave aspect of the trough belts does not lend itself to placing cleats within them.
Rubber conveyor belting is versatile and solves many problems faced in moving bulk material. With the right understanding of how different materials behave these belts can accomplish the job without sacrificing efficiency. Consult a bulk material conveyor expert before investing in a conveyor system if your requirements may be complex.