Development of the KSS1536 raw coal sizing screen for use in confined space

In order to surmount the technical bottleneck in installation of raw coal sizing screen in confined space, the KSS1536 screen has been specifically developed based on the center-of-gravity shift principle. An introduction is made in the paper to the working principle, fabrication material, structure of screenplate, and operating performance of the screen. The screen working with this technology can help promote rapid stratification of material, avoid piling-up of material at screen′s feed end, and allow the material to travel toward the discharge end at a lower speed for increasing coal sizing time and hence improving sizing efficiency. The screen plate is in form of a staircase with punched holes and incorporates the advantages of ordinary perforated plate and comb-type stair-step plate. In addition to increase of screening area, the use of the plate can avoid plugging of holes by coarser coal particles and cover-up of holes by finer coal. The screen is fabricated with low-alloy structural steel with a mechanical strength far higher than Q355. Stress analysis shows that the maximum stress to which the screen is subjected is 36.9 MPa, which is concentrated on the vibration excitation beam, and the screen box and various key components can all meet the designed requirements in rigidity and strength. As demonstrated by field application, the KSS1536 screen is suitable for use in confined space; when applied to the classification operation of materials after intelligent dry separation in Pingdingshan Bakuang Coal Preparation Plant, it can keep working reliably with a capacity of 300 t/h and an sizing efficiency reaching 90%; and it is easy in routine maintenance. The successful development and application of the screen can provide new ideas for the selection and process layout of raw coal classification screens under limited space conditions.