Cutter design and the arrangement of cutters on the shafts play a key role in determining shredding efficiency. The load on a shredder is primarily determined by the number of cutter hooks that are “engaged” at any particular point in time. The more hooks engaged, the higher the load. To manage the load in a shredder you need to manage the number of engaged hooks and this is done in a couple of ways.
The number of hooks on a cutter can be varied – single, dual, triple, six. The offset – or the degrees until the next adjacent hook, can also be varied. This enables the creation of spiralling of the hooks which is suitable for some applications – but not for all materials. Other applications require larger open gaps to enable large objects to enter the cutting zone. The correct use of equal speed and differential speed shafts is also essential to manage the load and create open areas. At Brentwood we design a cutter arrangement specifically to suit your materials and throughput requirements.
Brentwood’s cutters are manufactured from a nickel based alloy and case hardened to 60 Rockwell. This produces a cutter with excellent durability and superior shock tolerance so the cutter can withstand high impact loads which may occur when an unshreddable item enters the cutting chamber. Brentwood cutters are also repairable. We can hard face the cutting edges and regrind to specification several times over the life of a cutter. This greatly reduces the cost of ownership of a Brentwood shredder.
The overall length of the cutting chamber also has an impact on the throughput of a shredder. Longer cutting chambers can increase production rates where the input material is flowable and can move in the cutting chamber. Too long a cutting chamber however can increase load beyond the shredders limit and place higher levels of stress on the shafts.
Cutting chamber width – and more particularly, the distance between the shaft centres plays a crucial role in determining if a material can be effectively grabbed by the cutters. If the shaft centres are too close for a particular sized input material, then bridging may occur or the shredder may have difficulty in grabbing the material.
At Brentwood, we offer customised cutting chamber lengths to enhance throughput on certain materials and to allow longer items – such as pallets and IBC’s to be effectively shredded.
Industrial shredders are high-powered machines that cut through and destroy the toughest debris in all types of environments. They are primarily used in waste processing applications, often as the first step, to reduce the overall waste size and protect pumps and equipment from damage.
While all shredders serve the same purpose, they’re not all created equal.
In this blog post, we’ll explain the various types of industrial shredders and how they work.
The primary differences between shredder types are their overall design, how they cut materials, and how materials are fed into the hoppers.
As the name suggests, this type of shredder has a single, solid shaft with rotary blades. In this design, material is typically fed through a hopper and pushed towards the rotating shaft by a hydraulic ram. The rotating shaft then shreds the material into smaller pieces that can pass through a screen with specific hole sizes, determining the final particle size.
Its primary advantage is that it can process a wide variety of materials, including plastics, wood, rubber, and textiles. You can find single-shafted shredders in plastic recycling, wood processing, rubber and tire shredding, and textile waste applications.
A dual-shafted shredder works similarly to a single-shafted one, except it uses two counter-rotating shafts with blades that pull material through and shred it. They are particularly effective for heavy-duty shredding applications and are widely used in various industries to reduce the size of waste materials, including electronics, wood and biomass, metal, plastic, rubber, and other solid waste.
Quad-shafts have four intermeshing shafts fitted with cutting blades. The blades on the shafts rotate to pull in and shear the material, creating a consistent shredding action. The four-shaft design makes it well-suited for heavy-duty shredding applications, especially for high-security documents or difficult materials that may otherwise jam or clog in single- or dual-shafted shredders.
You will get efficient and thoughtful service from SVL.
Shear shredders use two or more counter-rotating shafts with cutting disks to create a “shearing” action that cuts the materials into strips or small pieces. The blades are positioned to overlap, ensuring the material is effectively grabbed and sheared as it passes through the rotating shafts. Single-, dual-, and quad-shafted shredders can be sub-types of shear shredders.
Shear shredders can handle large volumes of material quickly and process many types of materials. They’re commonly used to process plastic drums, pipes, and other bulky items and are ideal for any application requiring precise size reduction.
Pierce-and-tear shredders use slowly rotating shafts fitted with sharp, hooked blades. The hooks catch materials and pull them through the tearing mechanism. This cutting method is particularly effective for reducing the size of resilient materials and bulky or irregularly shaped items.
Rotary cutter shredders have a rotating shaft equipped with multiple cutting blades or knives. As the shaft rotates, the blades cut the material into smaller pieces. Shear and pierce-and-tear shredders are technically a type of rotary cutter.
This specialized shredder uses a rotating drum with cutting blades or hammers to shred materials instead of single or multiple rotating shafts. As the drum rotates, the attached blades or hammers cut, grind, and shred the material into smaller pieces. The material is typically fed into the shredder through a hopper or conveyor system, ensuring a consistent flow. A drum shredder can quickly process large volumes of materials, like organic waste and wood.
Grinders use high-speed rotating shafts or drums equipped with cutting blades or hammers to grind materials into smaller pieces. They’re called grinders because they use a grinding and cutting action to reduce particle size. They often operate at high speeds, which results in rapid size reduction and a finer output. This type of shredder is commonly used for grinding plastic waste like bottles, containers, and film, in wood and rubber processing applications, and in organic waste management.
Chippers feature a hopper or chute where materials are fed into the machine. Inside, a drum or flywheel with a set of sharp blades or hammers chips and shreds the materials into smaller pieces. They’re most commonly used to convert yard waste into useful mulch or compost, but there are also specialized plastic chippers used for processing high volumes of large items like crates or thick-walled containers.
Granulators are used to create granules of materials and are particularly useful in recycling and reprocessing plastics, especially in injection molding applications. They feature a rotor with multiple rotating knives and a stationary bed knife. The material is fed into the granulator, where the rotating knives cut it against the stationary knife, producing small, uniform granules.
Although hammer mills can be classified as shredders, they don’t actually “shred” material. Their design features a rotor with swinging hammers attached to it. Any material fed into the machine is pulverized repeatedly by the hammers until it’s fine enough to pass through the perforated screen. They’re widely used to process metals, plastics, wood, and organic waste.
Most industrial shredders can be classified as “hopper-fed.” This means that there is a hopper into which the material is fed into to be processed by the shredder. The hopper feed mechanism allows for easy and continuous feeding, making them suitable for high-volume applications. The hopper directs the materials into the shredding chamber, where rotating blades or knives cut them into smaller pieces.
Although hopper-fed is the most common type of industrial shredder, some shredders incorporate conveyor feeding. The conveyor belt system steadily transports materials directly into the shredding chamber. This design allows for continuous operation and reduces the need for manual feeding. Conveyor-fed shredders are commonly used in plastic recycling processes, as well as wood, metal, and textile waste processing applications. They’re also ideal for shredding mixed waste streams, bulky items, and construction debris.
The standard components of most industrial shredders include:
JWC Environmental is an industry-leading manufacturer of municipal and industrial waste processing equipment, including our renowned Monster® SHRED series, featuring five customizable hopper-fed shear shredder models.
If you want to learn more, please visit our website Rotary Shear Shredder.