An aggregate crusher is a machine designed to grind or pulverize various types of rock into small, relatively uniform pieces. Aggregate crushers are used in mining, quarrying, and recycling operations. During the primary crushing stage, the goal is to reduce the size of the materials so that they can be further processed in subsequent stages of crushing and screening to create the desired aggregate sizes.
The basic concept of an aggregate crusher involves a combination of crushing mechanisms. The materials are initially fed into a hopper, where they are loaded by an excavator or conveyor. This raw feed is then directed into the crushing chamber, where a series of heavy-duty jaws or hammers are used to break the larger rocks into smaller pieces.
There are several types of aggregate crushers, each designed for specific tasks:
Jaw Crushers: These crushers are commonly used as primary crushers. The raw feed is fed into a stationary jaw, which causes the material to be crushed against a fixed jaw. The movement of the two jaws creates compression and shearing forces, reducing the size of the material.
Impact Crushers: Impact crushers use the principle of impact to crush materials. The raw feed is directed into the path of rapidly rotating hammers or blow bars that strike the material and break it into smaller pieces. These crushers are often used for shaping applications to produce cubic and well-graded aggregates.
Cone Crushers: Cone crushers operate on the principle of compression crushing. A cone-shaped mantle is mounted on a vertical shaft, and the material is fed into the space between the mantle and the concave (the stationary outer surface). As the mantle gyrates, it crushes the material against the concave, producing finer, smaller-sized aggregates.
VSI Crushers: Vertical Shaft Impact (VSI) crushers use a different approach to crushing. They utilize the principle of centrifugal force to accelerate the feed material and throw it against a stationary surface, such as a rock bed or anvil. This impact causes the material to break along its natural cleavage planes, resulting in well-shaped and finely crushed aggregates.
The efficiency of an aggregate crusher is influenced by several factors, including the type of crusher, the size of the feed material, the desired product size, and the characteristics of the rock being processed. Proper maintenance, regular inspection of wear parts, and optimal feed control contribute to maximizing the crusher’s performance and lifespan.