What Is the Reduction Ratio of the Crusher?

When purchasing crushers, especially jaw crushers for coarse crushing, we often see a word: large reduction ratio. So, what is the reduction ratio of the crusher? What are the commonly used calculation methods?

What is the reduction ratio of the crusher?

    After the ore is blasted, there are mostly large stones of different sizes. They must be crushed by the crusher before they can meet the needs of the project. So do these stones need single-stage crushing or multi-stage crushing? The reduction ratio is a very important factor.

The reduction ratio refers to the ratio of the feed particle size to the product particle size in the crusher, which indicates the degree of material crushing, which directly affects the energy consumption and processing capacity of the crusher.

Commonly used calculation method of reduction ratio

    The reduction ratio has a professional calculation method, which is divided into three types according to different situations:

1. Particle size reduction ratio:the ratio of large block size before and after crushing

Calculation formula:I = larger diameter of feeding material / larger diameter of finished product

    Due to the different habits of each, the large-granularity value method is different. British and American take the sieve width at which 80% of the material can pass through the sieve hole as the large particle size diameter. China and the Soviet Union, 95% of the material can pass through the sieve hole width as the diameter of the large particle size.

Application object:This calculation method is often used in quarries because the width of the feed port of the crusher should be determined according to the large particle size of the ore in the design.

2. Surface reduction ratio:the ratio of the width of the crusher inlet to the width of the outlet

Calculation formula:I=0.85B/S (inlet width/discharge width referred to here)

0.85 is the width coefficient of the crusher to accommodate the material. The value S of the width of the discharge port: the coarse crusher is different from the medium and fine crusher, and the former takes the larger width; The latter takes the smaller width.

Application object:Because this method does not need to do screening analysis of a large number of materials, the approximate calculation can be carried out until the width of the feed port and the discharge port of the crusher, which is simple and fast, so it is widely used in production.

3. Average reduction ratio:the ratio of the average particle size of the material before and after crushing.

Calculation formula:I=average particle size of material before crushing/average particle size of material after crushing

Application object:Because the size and shape of the ores before and after crushing are different, they can only be represented by the average particle size. Therefore, the crushing ratio calculated by the average particle size can reflect the degree of crushing more truly, so it is mostly used in theoretical research.

    In actual production, the appropriate calculation method of the reduction ratio should be selected according to the specific work content of the crusher.