Drum type concrete mixers are important part of the concrete mixers available today. They are most suited for small to large capacity machines. As the name suggests, the mixer is drum type with an opening in one end or in some cases two ends. The material used to make concrete (aggregates, sand, cement, water) are mixed inside the drum as the drum rotates. But it is not as simple as it seems there are designed flights inside the drum that help in mixing and unloading the contents. The mixer is filled and emptied by rotating it in clockwise and anticlockwise direction, tipping it (tilting) or opening it. Rotation is controlled and suitable for better mixing.
Drum concrete mixers are known to have the lowest operating and maintenance costs among all mixers. They are used and preferred when the cost of production is one of the major factors. Even high volumes of concrete can be produced by the use of these mixers.
Major classification of these mixers can be in two types:
Non tilting mixers
As the name suggests the mixers will usually need to tilt during its course of action. They will have a single opening for feeding the materials. They usually work at an angle of 15 degrees Celsius and discharge is facilitated by the same opening in the drum mixer. They can handle large size of aggregates easily and the discharge is faster in such type compared to the non tilting type. Large size particles can be easily used with these mixers.
Non tilting mixers:
These types of mixers are best known as reversible type drum mixers. They are non tilting type and have two holes on the two sides for input and discharge. The mixer is fixed on its axis and does not move on the axis. The movement is only clockwise or anticlockwise. These are most suited for plants which are mobile or portable as they can be transported from one place to another for frequent site shifting. The concrete mixer drum design is designed in such a way that feeding can be done from one end directly by feeding bins or by belts which carry material directly into the mixer. Some models also have built in skip facility for loading contents. When the mixer moves in one direction, mixing takes place and when the mixer moves in another direction, the specially designed flights allow quick discharge of the concrete which will be ready to be used.