Types of Mixer:

Machine mixers are broadly classified in two categories, namely batch mixers and continuous mixers. Batch mixers are of two types, namely drum type and pan type. The drum type mixers can further be classified into tilting, non-tilting and reversing type batch mixers. This classification is shown in a block diagram.

Batch Mixers are those in which concrete ingredients are mixed in batches with certain time interval. In this category of mixers by the concrete is produced within batches but continuous concreting can be ensured by properly coordinating the various handling operations, placing, namely transporting, and compacting. These types of mixers are most common and are frequently used. Batch mixers are mainly available in two types, namely drum type and pan type. The drum type mixers are further classified as tilting type and non-tilting type mixers.

Continuous Mixers are those in which all the operations of mixers (i.e. feeding, mixing and discharging) are performed simultaneously and continuously so as to obtain the mixed concrete continuously. This type of mixers is used at large construction site where mass concreting is completed, such as construction of dam, etc.

Pan Mixer is basically a typical cylindrical container mounted on its vertical axis. One or two stars of paddles mounted on separate vertical axis are also provided in the pan. On the basis of whether the pan is rotated or the paddles, pan mixers may be of two types. One, in which the pan is static whereas the axis of stars moves along the circular path about the axis of the pan and the other, in which the paddles remain stationary and the pan rotates about its vertical axis during mixing operation. In both the types, the relative motion of paddles and the ingredients of concrete induce a thorough mixing action in every part of the concrete. Another attractive feature of the pan mixer is the provision of scraper blades, which prevents sticking of mortar to the pan sides by continuous scrapping. That is why, this type of mixers is more suitable for stiff and cohesive mix and being non-mobile type, commonly preferred on a large construction site or at pre-cast concrete factory.  The mixed concrete is discharged through the central hole provided at the bottom of the pan.