Disadvantages of Trommel Screens
There are a number of available material screening solutions. Material specifications will dictate the type of screening equipment that is most efficient for the given process. Trommels are one of the most commonly deployed screens for a number of jobs – from compost to municipal solid waste. However, despite their wide usage, trommel screens have a number of disadvantages that can make them less than ideal.
While trommels are frequently used to process materials, they do so inefficiently. Trommel screens are simple in design: a rotating cylindrical drum with perforation cavities which allow undersized material to pass through the screen.
The advantage of this design is a relatively lower cost. In fact, small, basic trommels can be made at home with relative ease. However, for heavy duty industrial applications, that same simplicity results in an overall inefficient design.
When compared to other solutions, like vibrating or disc screens, trommels simply cannot handle the same volume of materials. While rotating, only a portion of the screen is being utilized for sizing. Comparatively, the entire screen surface of other material screening solutions can effectively size materials. This not only places the trommel drum at a volumetric disadvantage to other screening equipment, but can also lead to additional material flow concerns.
When screening multiple particle sizes or when material begins to back up, trommels also have the disadvantage of plugging. Plugging occurs when a larger feed material gets stuck in the screen aperture. This can lead to further plugging or back up of material traveling through the drum.
When a plug happens, it can halt production, in turn lending to additional maintenance. Wet materials, though commonly processed through trommel screens, can cause additional hindrances to the screen.
Much like plugging, when sorting wet materials, trommel screens are prone to blinding. As wet feed materials, such as compost or solid waste, pass through the rotating drum, they can begin to clump and stick to the screen. This can cause further materials to build-up, leading to less efficient sorting if not halting production.
Even when blinding does not require immediate attention, it still requires cleaning of the trommel and can lead to additional maintenance. Cleaning of the drum and replacing trunion wheels and cleaning brushes can be costly.
Plugging, blinding, or simply regular use can cause damage to the trommel’s drum. While some minor damage is to be expected and can be prevented through proper usage and care, larger damage can be costly. One of the biggest disadvantages of the trommel screen’s design is the inability to replace part of the drum when damage occurs.
In the event that damage is unable to be repaired, the entire drum must be replaced. This is both expensive and can halt further production.
Aggregates Equipment, Inc. manufactures screening solutions which eliminate the disadvantages of trommel screens. Our BIVITEC® Screen features a dual-vibratory process which prevents clogging and blinding. Meanwhile, the Eco-Star® Dynamic Disc Screen features a patented anti-clogging system designed to handle the most difficult urban and industrial waste.