An impact crusher is a piece of heavy construction equipment people can use to reduce the size of things like rock, waste concrete, and similar materials. The operator feeds chunks of material into the machine's hopper and it crushes them, turning the pieces into small chunks of a more uniform size. They can be run through another crusher to make them even smaller, or used as-is, depending on the setting. Numerous companies manufacture impact crushers, including large stationary models, as well as portable equipment for job sites.
In a horizontal shaft impact crusher, material pours into a hopper with a rotating shaft. The shaft beats the material with a series of hammers to crush it into smaller pieces, and the crushed product pours out the bottom. A mesh only allows particles of a certain size through, keeping the output uniform. Vertical shaft impact crushers work by hurling materials against the size of a drum to fragment them. Depending on the velocity of the particles, they will break down into pieces of varying sizes. A screen allows materials of sufficiently small size to escape the drum.
One use for an impact crusher is in the processing of raw materials like those associated with mining. Smaller pieces can be made more compact and are easier and more efficient to transport. The reduced size can also make it easier to separate materials by type, allowing people to remove useful material and discard the rest. An impact crusher can be located on site, allowing for rapid materials processing before transportation away from the facility.
These machines are also useful for preparing material for recycling or disposal. Materials like concrete chunks can run through an impact crusher to produce a series of chunks available for use in recycled aggregate. Likewise, rocks can be crushed to break them down into smaller pieces, making them easier to discard. Impact crushers can also prepare materials like gravels for use, making sure they have a roughly uniform size so they perform as desired.
Like other heavy equipment, an impact crusher can be very dangerous. These machines operate at high speed and can break up very sturdy materials, making them potentially risky for people to work around. People usually need to wear eye and ear protection to prevent injuries, and must use caution around the equipment. The machine usually has an emergency stop for situations where people fall into the crusher, allowing personnel to quickly halt operations for a rescue or recovery operation.