how to calculate jaw crusher capacity

Calculating the capacity of a jaw crusher is essential for determining its performance and efficiency in crushing applications. The capacity refers to the amount of material the crusher can process within a given time, typically measured in tons per hour (tph). Several factors influence the capacity, including the crusher’s design, feed size, material properties, and operational parameters. Below is a step-by-step guide to estimating the capacity of a jaw crusher.

1. Understand the Crusher’s Physical Parameters
The first step is to gather the technical specifications of the jaw crusher, including:
– Gape (Feed Opening): The width of the crusher’s inlet where material enters.
– Closed Side Setting (CSS): The smallest distance between the fixed and movable jaws at the discharge point.
– Throw (Eccentric Stroke): The vertical movement of the moving jaw at the discharge end.
– Speed (RPM): The number of cycles the jaw completes per minute.

These parameters directly affect the crusher’s ability to process material.

2. Apply the Theoretical Capacity Formula
The theoretical capacity of a jaw crusher can be estimated using the following formula:

\[
Q = \frac{60 \times N \times s \times L \times CSS \times \mu}{1000}
\]

Where:
– Q = Capacity (tph)
– N = Speed of the crusher (RPM)
– s = Stroke of the swing jaw (m)
– L = Length of the feed opening (m)
– CSS = Closed Side Setting (m)
– μ = Material density (t/m³)

This formula provides an approximate value but does not account for material characteristics or crusher efficiency.

3. Adjust for Material Properties
Different materials have varying hardness, moisture content, and feed size distributions, which influence crushing efficiency. For example:
– Hardness: Harder materials reduce throughput due to increased resistance.
– Moisture Content: Wet or sticky materials may clog the crusher, reducing capacity.
– Feed Size: Oversized or poorly graded feed can cause uneven crushing and lower output.

Adjust the theoretical capacity by applying empirical correction factors based on material behavior.

4. Consider Operational Conditions
Real-world conditions such as feed rate, jaw wear, and crusher settings