Crusher – What Is It?
Release time: 2025-03-19
Crusher – What Is It? Types of Crushers and How They Work
Table of Contents
- What is a Crusher? Types of Crushers and Their Applications
- How It Works
- Types and Classification of Crushers
- Applications
- Design and Types
- Historical Background
- Video
What is a Crusher? Types of Crushers and Their Applications
Industrial crusher for polymers produced by SUHMAN in China.
A crusher is a specialized machine designed for the mechanical crushing of hard materials to reduce them to the required fractions. The crushing process is achieved through mechanical methods such as splitting, striking, or compressing. These machines are powered by hydraulic or electric drives to provide the necessary force.
Crushing machines can break materials down to fractions as small as 5 millimeters. For smaller fragments, shredders are typically used.
How It Works
Industrial crusher with a set of cascade blades.
Different types of crushers are designed for specific purposes and operate based on various principles. These machines can perform the following crushing methods:
- Tearing
- Compressing
- Cutting or loosening
- Impact methods: rebound plates, hammers
Each mechanism has unique design features that affect the final result. The most common machines compress material between two approaching surfaces, but there are also more specialized devices with distinct characteristics.
Types and Classification of Crushers
Crushers are classified based on their design, operating principles, and applications. Below are the main types of crushers:
Roll Crushers
Roll crusher with two rolls rotating towards each other.
The working mechanism involves two parallel rolls that rotate towards each other. Material is fed from the top, drawn between the rolls, crushed, and discharged as fine fractions from the bottom.
Types of rolls include:
- Toothed rolls – used for gripping and crushing large pieces of rock or ore by splitting.
- Smooth rolls – used for compressing small fractions of viscous and wet materials.
- Corrugated rolls – a hybrid that performs both compressing and splitting.
The final productivity of roll crushers largely depends on the strength and size of the rock. The size of the feed opening and the roll speed also affect performance.
Cone Crushers
Cone-type crusher.
Material is crushed in a ring-shaped space between a fixed outer conical bowl and a rotating inner cone. As the cones approach, the material is compressed and crushed, then discharged through a bottom opening.
Cone crushers have a complex design, making repairs and maintenance more challenging. However, they offer high productivity and efficiency compared to other types. Depending on size and design, they can crush various materials.
Hammer Crushers
Hammer-type crusher.
Hammer crushers are used for fine, medium, and coarse crushing of relatively brittle materials such as coal, gypsum, asbestos, limestone, or chalk. Crushing is achieved through mechanical impacts from high-speed rotating hammers. The material is broken not only by the hammers but also by collisions with the crusher housing. Fine fractions pass through grates at the bottom.
The final productivity of a hammer crusher depends on the type of rock and its moisture content. The size of the final fragments can be adjusted by changing the grate gap and the distance between the hammers and the grate.
Advantages: Compactness, simple design, and excellent crushing performance.
Disadvantage: Relatively fast wear of grates and hammers.
Rotor Crushers
Rotor-type crusher.
Rotor crushers are used for crushing relatively soft rocks with an initial diameter of no more than 10 centimeters. Feeding larger fractions can overload the rotor, causing imbalance and strong vibrations, which may damage the machine. This is a key drawback of rotor crushers. To mitigate this, techniques like "air cushioning" are used to protect the rotating shaft.
The main working part is a rotating rotor with blades or hammers. As the rotor spins vertically, centrifugal forces efficiently crush soft materials like polymers, coal, chalk, etc.
Rotor crushers have a compact design and high productivity but are limited to rocks no larger than 100 millimeters in diameter.
Jaw Crushers
Jaw-type crusher.
The design features two ribbed metal plates called jaws. One is fixed, while the other oscillates relative to the first. Some models have two moving jaws for increased productivity. Material is crushed as the jaws close and discharged through a bottom gap when they open.
Productivity depends on:
- Jaw oscillation frequency
- Type of rock, its strength, and degree of crushing
- Volume of material loaded
- Grip angle of the rock
On average, jaw crushers can process 1-500 tons per hour, depending on the above factors.
Advantages: Simple design, easy repair, and maintenance.
Disadvantages: High electricity consumption, strong vibrations that increase wear on connections and bearings, and sometimes uneven fraction sizes that can clog the machine.
Applications
Dovetail blade for crushers produced by SUHMAN.
Crushing equipment has a wide range of applications in industry and the economy. They are used to process rocks, metals, wood, rubber, polymers, soil, HDPE, LDPE, tires, and various wastes.
There are specialized crushers for crushing PET bottles, salt, film, bark, granite, and even pine cones. Universal models are also available for broader applications.
For small-scale production or home use, compact mobile crushers are used, while large industrial complexes rely on massive stationary machines for crushing rocks and metals.
Crushing technology is essential in mining, construction, and recycling centers in China for processing coal, gypsum, chalk, and other materials. The scope of such equipment is vast and continues to grow each year.
Design and Types
Belt drive of a rotor crusher from SUHMAN.
In addition to the main types of crushing machines, there are also hybrid versions that combine two crushing methods in one unit, such as jaw and rotor or hammer crushers.
The choice of a specific device depends on the technological tasks. Cone and jaw crushers handle very hard abrasive materials, roll crushers manage medium-strength rocks, and impact crushers work with brittle and viscous materials.
Historical Background
Stone crusher from the late 18th century.
The first prototype of a modern crushing plant was created in the late 15th century. It was a mechanism with shutters powered by a hydraulic drive. The design featured a wooden chute with metal reinforcement where the rock was fed. The main crushing elements were freely falling metal pestles with sharp tips. A new stage in crusher development began with the advent of the steam engine in the 17th century, allowing for more advanced machines.
