Classification of Industrial Agitators and Mixing Equipment

Types of Industrial Agitators and Mixers

The most commonly used agitators are the rotary type. Other types include pendulous, bubbling, flow mixers, centrifugal pumps, colloid mills, and ultrasonic vibrators.

Rotary agitators are classified according to the shape of the runner (impeller) and their speed:

High-Speed Rotary Agitators (High Revolution)

These agitators allow mixing in a shorter time. However, due to the increased energy supply provided to the product, it may undergo thermal degradation.

• Propeller (Helix) Agitators

  The impeller consists of a helix of two, three, or four blades. They work at high speeds, creating significant turbulence in the area near the impeller.

• Turbine Agitators

  These are centrifugal pump impellers working without a shell, submerged in the liquid being agitated. They operate at high or medium speeds and create a radial flow. They are particularly suitable for working with viscous fluids.

• Cone Agitators

  The impeller is in the form of a truncated cone subjected to a rotating shaft, arranged with its smaller base at the top. The circulation of fluid is produced by the difference in centrifugal force caused between the two bases of the cone, due to their different diameters.

• Disk Agitators

  They consist of one or more disks mounted on a shaft that rotates at very high speed. They result in a tangential flow due to friction between the disk and the liquid.

Low-Speed Rotary Agitators (Low Revolution)

• Paddle Agitators

  These consist of one or more series of horizontal arms mounted on a vertical axis. Each series may have several arms or blades, and they can operate with a fluid head or at an angle. Paddle agitators produce tangential flow and are generally less effective, requiring more energy than propeller or turbine types. However, they are used because they are adapted to very extreme cases and offer ease of modification. Short paddles are used for dispersions and solutions, and to maintain good dispersion in suspensions of solids. Long paddles are used to stir viscous slurries and dense masses.

• Anchor Agitators

  They work very slowly. Their arms are perfectly adapted to the shape of the container. Their mixing capacity and yield are small, and they are used when no other agitator can be utilized. They typically keep the surface of the containers clean. Therefore, they are indicated when preventing the deposition of solid particles on the container walls is desired, or when a very strong movement in the vicinity of the walls is needed to force heat transfer, preventing decomposition, and so on. They produce tangential flow.