Mining Sand Aggregate Trommel Drum Screen Design Parameters

Trommel screen design parameters are are mainly determined through the analysis of the main parameters and the study of the movement characteristics of the material in trommel screen. Although the trommel drum screen has been widely used, little research has been done on it. The parameters are mostly determined empirically during design. In this paper, the main trommel screen design parameters will be deduced through the study of material movement characteristics during the screening process.

Trommel drum screen is a widely used screening device that classifies materials according to the granularity by using a cylinder that performs a rotary motion. The screen mesh is usually perforated plate or woven net. When the drum is working, the drum body is inclined to be installed. Drum screen has higher working efficiency in practical application. Generally, the main parameters of trommel screen should be determined first in order to meet the design requirements when sieving the specified material. The main parameters generally refer to productivity, screening efficiency, mesh size, material characteristics, drum screen speed.

1. Productivity

refers to the processing capacity of the drum sieve per unit time, generally measured by volume.

2. Screening efficiency

Refers to the ratio of the actual amount of under-sieve to the theoretical amount of under-sieve.

3. Mesh size

It is the limit between the upper and lower sieve. The sieve hole size should be determined in consideration of the specific application of the drum screen.

4. Material characteristics

The material characteristics that affect the screening efficiency mainly include the unit weight of the material, the shape of the material, and the friction characteristics of the material.

5. Drum screen speed

Generally, in order to obtain a better screening effect, the material should be turned in the sieve.

The movement of the material in the drum sieve can be decomposed into linear movement along the axis of the screen body and plane movement perpendicular to the plane of the screen of the screen axis. The linear motion along the axis of the screen is caused by the inclined installation of screen , and its speed is the speed of  material passing through the screen. The movement of the material in the plane perpendicular to the axis of screen is closely related to the speed of screen body.

With the increase of screen speed, the material is dropped to a certain level after being brought to a certain height. This movement is called a drop motion, which is conducive to the screening. If the screen speed exceeds a certain threshold value, the material no longer falls off the screen surface and performs centrifugal movement, at this time the material cannot be screened. This critical value of the speed of the screen body is called the critical speed.