Reversible Impactor

The Reversible impactor is a highly versatile crusher. It is a open bottom type machine. It can be employed for crushing of hard coal and lignite in power plants, coking coal for the iron and steel industry, limestone and gypsum as well as other related minerals of soft to medium-hard consistency. Unlike hammer mills, reversible impactors have no cage bars, but crush by impact only. They have few parts to maintain or replace, and require relatively little power to operate.

As the material enters the reversible impactor, it is struck by massive steel hammers which cause it to fracture along its natural fault lines into smaller pieces. The material now moves at high velocity imparted by the swinging hammers. These pieces strike the stationary breaker blocks, resulting in further size reduction. The particles then rebound into the path of the hammers, repeating the reduction cycle, until the sized material exits through the open bottom of the crusher. This method of reduction produces a cubical product at high reduction ratios of up to 35 to 1, depending on the friability of the feed material. Over crushing and excessive production of fines are prevented because the bottom of the crusher is completely open, with no screen gratings to impede the flow of material. In addition, power requirements are less than that required by grate-type hammer mill and ring granulators for producing the same nominal output. Finally, when processing high moisture materials, this crusher reduces the chance of plugging.

With the ability of the rotor assembly to be rotated in either direction, the operator gains important advantages :

• Both hammer faces wear evenly.
• Breaker blocks on either side of the crushing chamber provide twice the wear area as compared to single direction crushers.
• Improved crushing performance as the hammers maintain a sharper profile, imparing a solid, direct impact to the incoming material.
• In a single direction crusher, hammers develop a rounded profile that delivers only a glancing blow to the material, resulting in lowered capacity and increased power draw.
• There is no need to pull the crusher out of service to manually turn the hammers.