How does a rock crusher make gravel?

A rock crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust. Here’s how it generally works to produce gravel:

1. Initial Input: Large rocks or raw materials are fed into the rock crusher. This can be done via a hopper or directly into the crushing chamber, depending on the type of crusher.

2. Crushing Process: The rock is subjected to mechanical force to break it into smaller pieces. There are several types of crushers, each using different methods to achieve this:

   • Jaw Crushers: These use two plates, one stationary and one that moves back and forth, to crush the rock.
   • Cone Crushers: These use a rotating cone inside a hardened bowl, crushing the rock between them.
   • Impact Crushers: These use impact rather than pressure to crush the material. They involve high-speed rotors with wear-resistant tips and a crushing chamber designed to throw the rock against hard surfaces.
   • Gyratory Crushers: These function similarly to cone crushers but have a steeper crushing chamber and are primarily used in the initial stage of reducing the size of big rocks.

3. Secondary Crushing: Often, especially for gravel production, the product from a primary crusher is screened for size, with oversize material being returned or fed to a secondary crusher for further size reduction.

4. Screening and Sizing: Once the rocks are crushed to the desired size, they are often passed through screens that separate the gravel by size. This sorted material can then be used for different applications, from roadbase to landscape gravel.

5. Output: The final product is sorted and conveyed to storage or directly to a loading facility. It can then be transported for use in construction, landscaping, and other applications where gravel is needed.

Different rock crushers and crushing processes are preferred based on the characteristics of the rock and the desired end-product size and shape.