The Working Principle of Shaftless Trommel

The working principle of the shaftless trommel involves mounting its roller device on a frame at an incline, utilizing a non-central shaft structural design. The motor drives rotation either by meshing a pinion gear with the drum’s large gear or via a chain drive engaging gears on the drum. Alternatively, the motor can drive the chain directly, or the drum may be supported by two idlers, which are driven by the motor to rotate the drum.

As the drum rotates under the driving mechanism, material entering the screen surface is turned and rolled due to the drum’s inclination and rotation. Qualified materials (undersize products) discharge through the outlet at the bottom rear end of the drum, while unqualified materials (oversize products) exit through the discharge port at the drum’s end. The continuous tumbling and rolling action within the drum helps eject any material stuck in the screen openings, effectively preventing blockages.

Application range of shaftless trommel

Shaftless trommel is mainly used for grading processing of belt-shaped and strong winding materials and is widely used in electric power, mining, metallurgy, building materials, chemical, and other production industries. It is often used for the classification of refractory materials, coal, fertilizers, and stones in sand fields, as well as the screening of viscous and wet materials such as coal, coke, white ash, and placer gold ore to make the product structure more even to meet production needs.

Shaftless trommel type classification

Shaftless roller screens can be divided into three types according to the transmission mode: gear transmission type, chain transmission type, and roller transmission type.

Advantages of Shaftless Trommels

Compared to central-shaft trommels, shaftless trommels feature a simpler structure. Several steel bars are uniformly welded around the drum near the vibration motor end, with the other ends converging at the drum’s central axis. Once fixed, these bars connect to the vibration motor via gears. When the motor starts, the drum rotates, utilizing the same screening principle as shaft-type drum screens.

Shaftless drum screens offer greater material efficiency and provide more space for screening operations. They are also easier to inspect and repair in case of failure, making them widely adopted in various applications. For instance, they are ideal for domestic waste pre-treatment, effectively filtering out required materials. The key advantage of the shaftless design is its ability to prevent material entanglement, resulting in relatively high screening efficiency.