Home > Encyclopedia

Impact Crusher

Impact Crusher

Impact Crushers(Impactors) comprise a lined chamber within which revolves a rotor on a horizontal axis. The rotor is fitted either with swing hammers located by pins or blow-bars of alloy steel located by mechanical or hydraulic clamps. The hammers or blow bars impart impact to the rock resulting in comminution that is energy efficient and a typically cubical product shape. Impact with the rotor, the chamber liners (breaker plates) and interparticulate collision all contribute to comminution. Reduction ratios of 20:1 are achievable in a single stage and even 40:1 for double rotor impactors. The impactor thus offers several potential advantages of high reduction ratio, low capital and operating cost, ease of installation and low head room requirement and good product shape. Product size can be varied within limits by changing rotor speed and the clearances between  rotor and liners.

The major limitation to the application of impactots is abrasive wear. Abrasive wear necessitates the costly replacement of hammers or blow-bars but, more importantly, results in loss of operating time, and low availability. Therefore, impactors tend to be restricted to crushing of non-abrasive rocks e.g. non-siliceous limestones and dolomites and to nonaggregate minerals e.g. coal, gypsum, salt. It has been stated that impactors are not suitable for rocks containing more than 5% free silica. Swing-hammer type impactors are generally applied to the production of the finer sizes of aggregate but impact becomes  ineffective at a particle size less than about 3 mm.

Impactors in Factory

The recent developments have mainly concerned the fixed blow-bar type which is now available as a primary crusher that can reduce very large lumps by a combination of impact and 'nibbling' actions. The use of a few large blow-bars forged from special alloys in place of many hammers and the design of the crushing chamber to permit very rapid access for maintenance, e.g. hydraulically actuated mechanisms for opening the casing and clamping wearing items, has overcome to some extent the principal disadvantage of impactors. They are now applied to the crushing of mineral ores, slags and siliceous limestones. Abrasive gritstones, quartzites and even basalt may also be crushed at the final stage by impactors when the value of the cubical shape produced justifies the cost, e.g. surface chippings  for roads or decoration.

In most cases the impactor operates in open circuit with no control upon product size other than clearances between rotor and liners, speed of rotation and feed rate. Caged hammer mills are available which include a discharge grating but the problems of wear and blockage can be severe and their use is usually restricted to soft minerals such as clays, coal, etc.

>>Previous: Gyratory Crushers, gyratory crusher working principle

>>Next: Vertical shaft impactors, What is Vertical shaft impactors?

Get Support & Quotation

Please fill in the form below(* are required), and we will get in touch with you as soon as possible.

Batching Plant Concrete Mixer Crusher Other


  • Nuclear Power Concrete Production LineNuclear Power Concrete Production Line

    Nuclear power project is less than hydropower project in concrete pouring volume, but compared with other projects, it still needs a large volume of concrete and its structure is more complex than hydropower project....

  • Mobile Crushing Plant for Construction Waste ProcessingMobile Crushing Plant for Building Waste Processing

    Due to the construction wastes usually were piled up concentratedly in relatively limited space with poor traffic condition, Camelway Machinery recommends wheel mobile crushing equipment to crush and screen the construction waste....

  • Diabase Crushing, Screening and Sand Making Production LineDiabase Crushing, Screening and Sand Making Production Line

    Diabase is a superior building material that can be used as asphalt concrete crushed stones for super highway pavement. The production mainly consists of jaw cr...

  • Production of lightweight aggregates,lightweight aggregate production lineProduction of lightweight aggregates

    Lightweight aggregate is used to produce lightweight concrete products such as concrete blocks, structural concrete, and pavement. It can be classified into 3 types--Structural lightweight aggregate, Masonry-lightweight aggregate and Insulating aggregate....

  • Concrete Mixing Plant for Concrete BlocksConcrete Mixing Plant for Concrete Blocks

    The production of concrete blocks on block machines has become one of the most popular industrial prefabrication methods in the construction sector worldwide. T...

Contact Us

Tel: 008637165861518

Fax: 008637165861528


Mobile: 008618838109566

WhatsApp: 008618838109566

Skype: Camelway1983