As a kind of livestock manure treatment method, aerobic composting has the advantages of safety, high efficiency and environmental protection, and has been widely applied. The mechanization and specialization of its production process have been improved continuously, so the corresponding requirements of the equipment have been put forward. In this paper, a compost trommel screening machine is designed for the screening operation in composting process, which has certain practical value and theoretical significance. By analyzing the material motion and the screening process in the trommel, a series of quantitative and qualitative conclusions related to the structural parameters and process parameters of the trommel screening were obtained, based on these conclusions and combined with the characteristics and requirements of composting production process, calculated and designed the trommel screening machine. The trommel screening mainly deals with the composting products for livestock and poultry manure, witch material bulk density of about 0.7t/m3, and the trommel screen has a processing capacity of 5t/h. Calculate the diameter, length and rotation speed of the trommel with mathematical model of trommel design, and designed the key components of the equipment, like stander and cover parts, support wheel and Block-wheel parts, feed and discharge port, etc. Use the finite element analysis software check and analyze the sprocket, and the final design parameters are determined. The discrete element method software is used to simulate and analyze the factors that affect the work efficiency of the trommel screen machine, and the original design parameters are optimized according to the test results.
The prototype of the equipment is manufactured and tested. The test results show that the design of the compost drum screening machine runs smoothly and the working condition is normal, and conforms to the design requirements.
The common compost screening equipment includes vibrating screen, shaking screen, trommel screen. Materials to be treated include compost materials and compost products. The character of the compost material is that high viscosity, high moisture content, definite corrosion, high content of organic matter, more subdivision materials and rich fiber materials. Because of its working characteristics of the vibrating screen in compost industry are easy to produce large dust, at the same time, the sealing system of the vibration of the screen surface vibrating screen is not strict, in addition, it lead to the leakage of dust, and if the material contains a large mass of objects such as stones, bricks, etc., it is easy to cause damage to the screen surface. In the running process of the vibrating screen, the phenomenon of screen blockage occurs frequently, the wear speed is fast and the screen is not easy to clean, the equipment maintenance workload is large, and it need to stop frequently maintenance, and it also impact the normal production of compost processing.
Trommel screen is a common screening equipment in compost production. The working process is relatively stable, the noise is low, the impact of materials on the screen surface is not large, and the service life of the screen surface is longer than that of the vibrating screen. The trommel screen has strong turning ability to materials, and it is easy to produce dust in the working process. The problem of dust pollution can be effectively solved through reasonable design. The trommel screen can be used for the pre-treatment of compost materials and processing of compost products. Especially, It has great working performance for screening the compost material. Generally speaking, the work processing of the trommel screen is smoothly with low noise, the impact of materials on the screen surface is small, and the service life of the screen surface is long. It is suitable for processing materials with complex composition and high moisture content, and is a common screening equipment in composting production.