About Industrial Shredders: Applications and Selection Criteria

Shredders play an indispensable role in many applications, including manufacturing, recycling, solid waste reduction, security, wastewater treatment, oil and gas production, transportation and biosolids production, and more. Shredding offers a multitude of benefits besides the most obvious: size reduction. Shredders are used to process materials used to produce a product or fuel, protect business intelligence by destroying sensitive products or documents, recycle products or waste, and shred solids to ensure other equipment or processes run smoothly. Corporations, government agencies, and municipalities employ shredders.

APPLICATIONS

Some industrial applications for solids reduction include the destruction of food, pharmaceuticals, rubber, pallets, steel and plastic drums, furniture, construction debris, tires, containers, corrugated boxes, packaging, labels, and other bulky materials. Industrial shredders are also used for the destruction of documents, x-rays, media such as hard drives, and other electronic devices to protect the privacy of individuals and corporate information.

Municipal applications include recycling centers and smaller multi-cutter shredders for finer reduction for use in wastewater treatment plants. The recycling industry has found many uses for shredders, such as tire shredding for rubber recovery. This recycled rubber is found in many applications and products, including hot melt asphalt, basketball courts, playgrounds, and footwear products. Rubber is also used in civil engineering practices for roadway subgrade insulation, fill, and as fuel as “tyre-derived fuel”. Waste wood is shredded for recycling and used to make many types of wood products, such as particle board and paper. Plastic bottles are recycled into PET (polyethylene terephthalate) plastic chips for the production of new bottles. Recycling or reusing all of these products through shredding reduces waste in the environment, increases corporate profitability and reduces carbon emissions.

SELECTING THE RIGHT SHREDDER

Type of Material to Process

Different types of crushers excel at processing specific materials. Tree branches are usually shredded with a high-speed chipper. However, plastics are most often processed in a granulator (rotary blade cutter); bulky forms of plastic are often placed in a shredder as the first stage before pelletizing. When you plan to shred automobiles, this type of application is usually accomplished with a hammer mill. Although processing a variety of waste materials may require versatility with a minimum amount of noise and dust, a two-shaft shredder may be the optimal solution.

desired output

Understanding the outlet size requirement will help determine the type of equipment to install. Some facilities require the material to be separated, while others may need to be re-crushed and ground. A single-pass crusher will cost less, but if the material needs to be reduced to a very small size and compressed, compaction equipment may be required.

Ability

Choosing a crusher that handles the correct capacity is important to the success of any installation. Capacity is usually expressed in pounds per hour and is determined by physical size, weight (bulk density), and amount of material to be crushed. Capacity may be limited by the size of the cutting chamber. Please check the capacity rating carefully before purchasing the machine and allow excess capacity. Using a shredder with a maximum capacity that is too close to the desired capacity can shorten life. However, oversizing a shredder by a wide margin can lead to excessive energy use and take up too much floor space.

Feed Type

Two basic types of feeding are common: manual and automatic. Manually fed shredders typically have a hopper and work by feeding the material by hand or using a forklift to drop the material. Automatic feeders or conveyors help optimize crusher performance by providing a consistent and regular supply of materials to the crusher.

Operational considerations

Portability, safety, and noise are concerns when selecting a shredder. Select the proper location for the crusher because it is not easy to move a machine that weighs half a ton or more. Depending on the material, dust and other particles in the air can be an environmental hazard. Noise is another factor to consider, as some crushers (such as hammer mills) generate more noise than others.

Maintenance

Shredders endure a great deal of stress and maintenance is necessary to keep them running efficiently. Cutters, blades or hammers will wear out with normal use and will need to be sharpened, adjusted or eventually replaced. Consider maintenance, repairs, and ease of obtaining replacement parts when choosing a manufacturer. Always evaluate the location of service access when determining where to locate any equipment, including your crusher.

DOUBLE SHAFT SHREDDER

One of the most versatile types of shredders is the twin-shaft shredder, such as the Franklin Miller TASKMASTER shredder. These devices employ two parallel stacks of counter-rotating cutters that engage at low speed under extremely high torque. As cam-shaped cutters are engaged with a tight clearance, they cut, shear, rip, slice, and tear a variety of materials into smaller pieces, usually strip or chip-shaped. The geometry of this dual shaft cutter also makes it very good for feeding irregularly shaped solids. This type of crusher generally does not employ a size screen, so the output particle is determined by the shape of the cutter. Dual shaft shredders can be designed for specific solids like tires, medical waste, documents, liquid bottles and more. The specifics of the application determine the configuration of the unit, although some crushers are designed specifically for a single application and are not versatile by any means. Shredder model numbers generally describe the length and width of the unit’s cutting chamber. The complete unit usually consists of the main cutting mechanism with shafts, cutters, bearings, transmission and housings, bracket, hopper (a funnel as a feed conduit), and a controller mounted on the unit or elsewhere.

In operation, material is fed into the unit’s top hopper and discharged from the bottom. Some crusher designs can be configured both vertically and horizontally. Specific designs are equipped with advanced shaft seals and sealed housings suitable for handling liquids.

Since there are varying degrees of quality, precision, engineering, and care of different crusher sources, the choice of a manufacturer and the type of crusher can greatly influence the success of the installation.

CRITERIA FOR SELECTING THE RIGHT SHREDDER:

• Is the crusher rated for capacity to meet your requirements?

• Is the shredder from a manufacturer with long-term experience and a reputation for customer service?

• Can the crusher handle your material and achieve the desired output particle size and consistency?

• Is the grinder rated for liquids in addition to solids, if necessary?

• Does the crusher have a proper cutting chamber design and size for your materials?

• Do you have electrical service to meet your power requirement?

• Is the shredder available with the options or materials you need?

• What are the maintenance requirements?

• Is the crusher robustly designed for long-term dependent operation?

• Does the manufacturer offer support and guidance to help you select, install, and support the equipment?

IN SUMMARY

As you can see, there are many considerations before selecting a suitable shredder. Gathering all the information necessary to match the specifications of the crushers will help shorten the process of adapting the equipment to your needs. If you are thinking of recycling, check that you have the necessary permits. Seeking the experience and advice of a reputable company is a good start and requesting a demo with a sample will confirm the effectiveness of the shredder. Visit the manufacturer’s website to review the company’s history and read some case studies to learn how other companies have used crushers to solve operational problems. The last part of the equation is determining your budget. Keep in mind that some units, while less expensive initially, may be of inferior quality and actually cost more in the long run to operate and maintain.