crusher principle of operation

# Principle of Operation of Crushers

## Introduction

Crushers are essential machines used in mining, aggregate production, and recycling industries to reduce the size of large rocks, ores, and other materials into smaller, more manageable pieces. Understanding the principle of operation of crushers is crucial for optimizing their performance, improving efficiency, and minimizing wear and tear.

This article explores the fundamental principles behind crusher operation, covering different types of crushers, their working mechanisms, forces involved, and factors affecting their efficiency.

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## 1. Overview of Crushers

Crushers are classified based on their mechanism of action and the stage at which they operate in the crushing process:

1. Primary Crushers: Designed to handle large feed sizes (e.g., jaw crushers and gyratory crushers).
2. Secondary Crushers: Used for intermediate crushing (e.g., cone crushers and impact crushers).
3. Tertiary Crushers: Produce finer particles (e.g., vertical shaft impactors).

Each type operates differently but follows fundamental principles involving compression, impact, shear, or attrition forces.

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## 2. Fundamental Principles of Crushing

Crushing involves applying mechanical forces to break down materials into smaller fragments. The key principles include:

(a) Compression Crushing
Compression occurs when material is squeezed between two rigid surfaces until it fractures. This principle is dominant in jaw crushers and cone crushers.

– Force Application: Two plates (one fixed and one moving) compress the material.
– Energy Efficiency: High energy efficiency due to direct force application.
– Particle Shape: Produces cubical particles with minimal fines.

(b) Impact Crushing
Impact crushing relies on high-speed collisions between hammers/blow bars and feed material.

– Force Application: Rapid kinetic energy transfer fractures brittle materials.
– Energy Efficiency: Less efficient than compression but effective for softer materials.
– Particle Shape: Produces irregularly shaped particles with more fines.

(c) Shear & Attrition Crushing
Shear forces slice material between moving components (e.g., roll crushers), while attrition grinds particles against each other (e.g., ball mills).

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## 3. Working Mechanisms of Different Crusher Types

(a) Jaw Crusher
Principle: Compression crushing
Components: Fixed jaw + movable jaw
Operation:
1. Material enters through the feed opening.
2. The movable jaw moves cyclically