design calculation gyratory crusher ppt

# Design Calculation for Gyratory Crusher PPT

## Introduction to Gyratory Crushers

Gyratory crushers are essential equipment in the mining and aggregate industries, designed to crush large rocks into smaller particles efficiently. Unlike jaw crushers, gyratory crushers operate with a gyrating motion, providing continuous crushing action. Proper design calculations are crucial to ensure optimal performance, durability, and energy efficiency.

## Key Design Parameters

1. Feed Opening and Capacity
The feed opening determines the maximum size of material that can be processed. The capacity of a gyratory crusher depends on factors such as:
– Feed size distribution
– Closed Side Setting (CSS)
– Eccentric throw
– Crushing chamber profile

A well-designed feed opening ensures uniform material flow and prevents choke feeding, which can reduce efficiency.

2. Crushing Force and Power Requirements
The crushing force is influenced by the hardness of the rock and the desired reduction ratio. The power requirement (P) can be estimated using Bond’s Law or empirical formulas:

\[ P = \frac{W_i \times Q}{\sqrt{F_{80}}} – \frac{W_i \times Q}{\sqrt{P_{80}}}} \]

Where:
– \( W_i \) = Work index (kWh/ton)
– \( Q \) = Throughput capacity (tons/hour)
– \( F_{80} \) = Feed size (μm) at 80% passing
– \( P_{80} \) = Product size (μm) at 80% passing

3. Eccentricity and Gyration Speed
The eccentricity determines the stroke length of the mantle, affecting the crushing action. The gyration speed must be optimized to balance productivity and wear:

\[ RPM = \frac{60}{2\pi} \sqrt{\frac{g}{r}} \]

Where:
– \( g \) = Acceleration due to gravity (9.81 m/s²)
– \( r \) = Radius of gyration (m)

Excessive speed leads to premature wear, while insufficient speed reduces throughput.

4. Chamber Design and Liner Selection
The crushing chamber profile influences particle breakage efficiency. Key considerations include:
– Concave angle – Affects nip angle and compression ratio.
– Liner material – High manganese steel is commonly used for durability.