How do you calculate the size reduction ratio of a crusher?

To calculate the size reduction ratio of a crusher, you need to understand the relationship between the feed size and the product size. The size reduction ratio is a measure of the extent to which the material is reduced in size by the crusher. Here’s a detailed explanation of how to calculate it:

Definition

The size reduction ratio (also known as the reduction ratio) is defined as the ratio of the feed size to the product size. It is a measure of how much the material is reduced in size by the crusher.

Formula

The size reduction ratio can be calculated using the following formula:

$$\text{Size Reduction Ratio}=\frac{\text{Feed Size}}{\text{Product Size}}$$

Where:

• Feed Size is the size of the material before it enters the crusher.
• Product Size is the size of the material after it has been crushed.

Steps to Calculate

1. Determine the Feed Size: Measure the size of the material before it enters the crusher. This is typically done by taking the average size of the material, which can be determined by sieving or other measurement techniques.

2. Determine the Product Size: Measure the size of the material after it has been crushed. Similar to the feed size, this can be done by taking the average size of the material after it has passed through the crusher.

3. Apply the Formula: Use the formula mentioned above to calculate the size reduction ratio.

Example Calculation

Suppose you have a crusher with the following measurements:

• Feed Size: 100 mm
• Product Size: 25 mm

Using the formula:

$$\text{Size Reduction Ratio}=\frac{100\text{ mm}}{25\text{ mm}}=4$$

This means the size reduction ratio is 4, indicating that the material has been reduced to one-fourth of its original size.

Importance of Size Reduction Ratio

• Efficiency: A higher size reduction ratio indicates a more efficient crusher, as it can reduce the material to a smaller size in fewer stages.
• Selection of Crusher: Knowing the size reduction ratio helps in selecting the appropriate crusher for a specific application, ensuring that the crusher can handle the required feed size and produce the desired product size.
• Performance Monitoring: Regularly calculating the size reduction ratio can help in monitoring the performance of the crusher and identifying any potential issues that may affect its efficiency.

Factors Affecting Size Reduction Ratio

• Type of Crusher: Different types of crushers (e.g., jaw crushers, cone crushers, impact crushers) have different size reduction capabilities.
• Material Properties: The hardness, abrasiveness, and moisture content of the material can affect the size reduction ratio.
• Crusher Settings: The settings of the crusher, such as the closed side setting (CSS) and open side setting (OSS), can influence the size reduction ratio.

By understanding and calculating the size reduction ratio, you can optimize the performance of your crusher and ensure that it meets the requirements of your specific application.