Cement raw materials occur in various hardness's which, combined with other factors, determine the mode of comminution prior to mill grinding. Some raw materials can be crushed down to mill feed size in one stage while hard materials may require two-stage crushing, i.e. primary crushing followed by secondary crushing.

The hammer crushers without inlet grate are basically secondary crushers, but their robust and sturdy design makes them well-suited for primary crushing for materials which have been quarried by ripping or similar fragmenting methods as well as for gypsum and raw coal. They can also handle materials containing some degree of moisture.

FLSmidth hammer crushers without inlet grate are available with rotational speeds suitable for primary as well as secondary crushing, and can be tailored to suit individual raw materials. The slot widths in the outlet grates may be adapted to the operational conditions in question.

FLSmidth hammer crushers without inlet grate are available with one or two sets of rotors. The rotor shafts are fitted with hammer discs on which the hammers are pivotally mounted.

The rotor shafts run in sturdy oilbath-lubricated roller bearings and are supported on the crusher casing of heavy cast steel and weldedup sections bolted together. The casing is fined with replaceable wear plates.

The double hammer crusher has a heavy anvil with replaceable crushing plates which are adjustable in relation to the hammers to compensate for wear. The double hammer crusher has a heavy anvil with replaceable crushing jaws and outlet grate, both of which can be adjusted to compensate for wear.

The single hammer crusher has an outlet grate with replaceable grate bars and an adjustable crushing plate.

FLSmidth hammer crushers without inlet grate are designated EUI (single without inlet grate) and DUI (double without inlet grate), followed by two digits specifying the diameter across the hammers and the width of the rotor unit.