Hammermill

A hammer mill (also called hammer mill ) is a milling machine. Your task is quick and depending on the application different coarse crushing various materials and especially strongly heterogeneous material mixtures.

Operation

The material is comminuted done by the kinetic impact effect. In a metal casing, a rotor is rotated at its outer circumference an application specific number of moving steel hammers are mounted, the peripheral speeds of up to 120 m / s can be reached. The rotor is usually directly driven by a motor and is housed with the hammers in a housing, which includes a screen in the interior of. Upon entry into the range of the rotor, the ground material hits the rotating hammers. By the blow of the hammers of the largest crushing effect. The hammers throw the pieces in addition to the grinding wall, where they are broken by the impact further.

A further reduction takes place in the lower area between the rotor and grinding wall. The ground material remains in the grinding chamber until it is so small that it fits through a hole sieve on the outer circumference of the machine. This screen has the function of a top cut, by exchange of the screen allows you to set the maximum grain size. A separation into several fractions is not possible here.

By the impact walls arranged on both sides of the rotor rotational direction can be changed ( reversing). This makes it possible to optimally exploit the hammer heads in wear.

After a small gap is usually still below a conical outlet, which is directly connected to a suction pneumatic ( mostly still with an alphorn ). Case, the milled product is extracted directly below the hammer mill with the suction pneumatic, which also provides a cooling of the machine ( by air passage ). This is very important for the grinding quality and machine.

Use

Hammer mills are used as grain and feed mills, in the food industry, for grinding of wood waste, plastic waste, etc.

When used in the recycling industry, the focus is on a break-up of material mixtures and less on a crusher. The advantage is that the crushing of the various material mixtures, as a precursor to subsequent varietal separation. For example, a mixture of materials of plastic and soft metals (aluminum, copper) are broken so that it can subsequently be isolated on Separiergeräten according to specific weight. Typical applications are refrigerator preparation and electrical and electronic scrap processing.

When used in a coal fired power plant coal, limestone, gypsum stones and minerals and salts are crushed.

In the wood pellet industry are hammer mills for crushing sawmill by-products such as sawdust, wood shavings and industrial wood used, and from the fuel produced wood pellets.