The basic process and operation points of sieving garbage with Trommel Screen

Introduction: The trommel screen is a key equipment in the garbage disposal system, which is used for the preliminary sorting of urban domestic garbage and other solid waste. Its working principle is based on a rotating cylindrical screen, which separates materials of different particle sizes through centrifugal force and gravity. When the garbage enters the drum, small particles smaller than the diameter of the screen hole (such as soil, fine organic matter) pass through the screen hole and become the undersize, while larger objects (such as plastic bottles, metal cans, etc.) remain on the screen surface and are discharged as the oversize.

Trommel Screen

The Trommel Screen has the advantages of simple structure, large processing capacity, and convenient operation and maintenance. It is widely used in the pretreatment stage of garbage sorting. However, when facing garbage containing a large amount of sticky substances or easily entangled objects, the Trommel Screen is prone to blockage and entanglement problems, affecting the sorting efficiency. To solve these problems, pretreatment measures are usually combined, such as crushing and mixing dry materials to reduce viscosity, and designs with self-cleaning functions, such as brushes or scrapers, are used to remove adhesions to ensure that the screen holes are unobstructed.

In addition, optimizing the operating parameters of the Trommel Screen, such as adjusting the feed rate, inclination angle and rotation speed, is also an important means to improve the screening effect. Regular inspection and maintenance are also indispensable, which can ensure the long-term stable operation of the equipment. For specific types of garbage, other sorting technologies can also be considered as supplements, such as wind separation, magnetic separation, etc., to achieve more refined classification.

Trommel Screen

A. The basic process of sieving garbage with a Trommel Screen

The Trommel Screen is a commonly used garbage sorting equipment, mainly used for preliminary physical sorting of urban domestic garbage, industrial waste, etc. It separates materials of different particle sizes through a rotating cylindrical screen for subsequent processing or recycling. The following is the basic process of sieving garbage with a Trommel Screen:

1. Feeding: The garbage is first fed into one end of the Trommel Screen, usually through a conveyor belt or other feeding equipment.

2. Screening: There are one or more screens with holes inside the Trommel Screen, and the size of these holes depends on the size of the material to be separated. When the drum rotates, fine particles smaller than the diameter of the sieve hole (such as soil, sand, fine organic matter, etc.) will fall through the sieve hole and become the undersize; while larger objects (such as plastic bottles, metal cans, large pieces of organic waste, etc.) remain on the screen surface, continue to move forward as the drum rotates, and are eventually discharged from the other end of the drum to become the oversize.

3. Cleaning: In order to ensure the screening efficiency, the Trommel Screen may be equipped with brushes or other cleaning devices to prevent the sieve holes from being blocked and ensure that the material can pass smoothly or remain on the screen surface.

4. Classification and collection: The undersize and oversize are collected in different areas or containers for subsequent processing. For example, the undersize may be directly used as landfill material or used for composting, while the oversize may require further manual sorting or other mechanical sorting.

5. Adjustment and maintenance: Depending on the composition of the garbage, the operator may need to regularly adjust the working parameters of the Trommel Screen, such as speed, tilt angle, etc., to optimize the sorting effect. At the same time, regular maintenance and inspection of the equipment are important links to ensure its efficient operation.

Trommel Screens have been widely used in the field of solid waste treatment due to their simple structure, convenient operation, and large processing capacity. However, for garbage containing a large amount of sticky substances or easily entangled items, the effect of Trommel Screens may be affected, so in practical applications, it is often necessary to combine with other types of sorting equipment for use.

Trommel Screen

B. How does the Trommel Screen deal with garbage containing a large amount of sticky substances or easily entangled items?

Trommel Screens face some challenges when dealing with garbage containing a large amount of sticky substances or easily entangled items, because these substances are easy to clog the screen holes or entangle on the drum and other mechanical parts, reducing the screening efficiency and even causing equipment failure. In order to effectively deal with these problems, the following measures can be taken:

1. Pretreatment:

a. Crushing: Before entering the Trommel Screen, use a crusher to pre-crush large pieces of easily entangled garbage (such as plastic film, ropes, etc.) into smaller pieces to reduce the risk of entanglement.

b. Mixing: If possible, try to mix the more sticky garbage with dry, coarse-grained materials to reduce its viscosity and make the screening smoother.

Trommel Screen

2. Improve the design of Trommel Screen:

a. Self-cleaning function: Use a Trommel Screen with automatic cleaning device, such as installing a brush, scraper or water spray system to help remove materials adhering to the screen and prevent the screen holes from being blocked.

b. Special shape of screen holes: Design special screen hole shapes (such as long strips or stars) to prevent slender objects from directly passing through or getting stuck in the screen holes.

c. Adjustable tilt angle: Increase the tilt angle of the drum to speed up the material passing speed and reduce the time the material stays on the screen surface, thereby reducing the possibility of adhesion.

Trommel Screen

3. Optimize operating conditions:

a. Control feed amount and speed: Ensure appropriate feed rate to avoid too much material entering the Trommel Screen at one time, which can reduce the chance of entanglement and allow the cleaning device enough time to work.

2. Adjust the drum speed: Adjust the drum speed appropriately according to the material characteristics to find the best operating speed that can ensure good sorting effect and reduce adhesion and entanglement.

4. Regular maintenance:

Regularly inspect and maintain the Trommel Screen, clean up the accumulated sticky materials and entanglements in time, replace worn parts, and ensure that the equipment is in good working condition.

Technical parameters of Trommel Screen：

5. Subsequent processing:

For materials that have passed the Trommel Screen but still have many problems, consider introducing other forms of sorting technology as a supplement, such as wind separation, magnetic separation, optical separation, etc., to further improve the sorting quality.

For garbage containing a large amount of sticky substances or easily entangled items, it is necessary to comprehensively apply the above strategies, starting from multiple aspects such as equipment design, operation management and maintenance, in order to effectively improve the working efficiency and reliability of the Trommel Screen.

PS: The Trommel Screen plays an important role in solid waste management. Its effective application helps to improve resource recovery rate, reduce environmental pollution and promote sustainable development.

Author : Serena Chang

Serena Chang is the writer of blog and news column. With more than 10 years of working experience in the machinery industry, she has a comprehensive understanding of environmental protection machinery and is willing to share useful knowledge of environmental protection machinery.