Waste pretreatment system mainly divided into three parts, crushing, screening and conveying. Crusher can be divided into Impact type (suitable for brittle hard materials such as stones), compression type (suitable for glass and other brittle materials), friction type, cut type(suitable for bulk matter) and so on; Sorting machine can be divided into screening (trommel screen, vibrating screen, fixed screen, etc.), air separation, magnetic separation, hand selection, etc. Screening technology is widely used in environmental protection, coal, metallurgy, chemical industry, medicine, light industry and other industries. Trommel screen plays an indispensable role in waste treatment system. The typical process of waste comprehensive utilization treatment system is that raw refuse firstly through bag breaking machine, crusher, which will be the larger pieces of garbage broken; After the broken garbage into the double sieve trommel screen, the small size of the screening material calorific value is very low, can heap the content of the content of rot is less, generally used for landfill or do compost filling and feeding, the medium size of the screening material (mainly are kitchen waste, paper and metal etc), It can be used for incineration and compost; The medium size of the screening material used for incineration are then transported to the incinerator waste storage pit by air separation equipment. The heavy materials are recycled by magnetic separation and then buried. The large-sized material sieved by the double screen trommel screen is hand-selected, and the large incombustible materials are sorted out for landfill, the metal glass is sorted and recovered, and the remaining items are incinerated in an incinerator, and after the above treatment, the The size of the incinerator is small, there is no large incombustible material, it is easy to feed and slag, and the calorific value of the incoming garbage is improved, which is conducive to combustion stability and control of atmospheric pollutant discharge. The design can be based on different needs and Garbage conditions, increase or decrease and adjust some equipment. If there are more recyclable materials, you can put the hand-selected line behind the bag-breaking machine to prevent some useful materials from being destroyed by crushing and other processes: for sorting glass bottles and plastic bottles, etc. A vibrating screen can be arranged. As the main screening equipment of the garbage transfer station, the trommel screen is an important part of the garbage pretreatment equipment and is used first in the garbage sorting process. The trommel screen is a machine that uses the cylindrical sieve body to make the rotary motion to classify the garbage according to the particle size. The sieve surface is a perforated thin plate, and the sieve body is installed obliquely. The material enters the sieve body and spirally rotates with the rotation of the sieve body, and the particle size is smaller than the sieve. The material whose particle size is smaller than the sieve hole is called the material under the sieve, and the material left in the sieve body is called the material above the sieve. which is discharged from the bottom end of the sieve body. The length, diameter, rotation speed, inclination angle, mesh diameter and perforation rate of the sieve cylinder directly affect the roller. The sieving effect of the trommel screen is designed to meet the power and residence time required for waste separation. Since there is a wrap between plastics and the like, it is not easy to fall through a general circular sieve hole, and the actually separated garbage has a smaller particle size than the mesh size.
The best way to deal with the urban waste that has been produced is to recover the materials and energy from the waste, so as to realize the resource and harmlessness of the waste, rationalize the treatment, reduce the running cost, improve the economic benefits, etc. The key technology of all is the sorting of garbage. Trommel screen therefore play a vital role in the waste treatment system. Organic compounds in food were screened out and treated by compost method, plastics and rubber can be used to produce combustible gas and fuel oil by pyrolysis. Incombustible materials that cannot be recycled are incinerated, and heat energy is recovered: stone, brick, and incineration residue can be used as building materials. Or landfill treatment. This will contribute to sustainable development and the realization of the scientific development concept.