Jet Mixers

Introduction
Jet Mixers are one of the simplest devices to achieve mixing. Side Entry Mixers or Jet Mixers are commonly used to achieve mixing in Storage Tanks and Reactors. Impellers are the conventional devices used for mixing in industry, but they are expensive for large storage tanks and underground tanks. Jet Mixers have been an alternative to impellers in the process industry. Compared with Mechanically agitated mixers, mixers that use jet technique to create high turbulence, high shear rates and vortex motion offer several advantages in achieving rapid mixing over a short period of time without any moving parts.

Working Principles
The liquid Jet Mixer entrains and pumps out a low pressure liquid utilizing a high pressure motive liquid. The high pressure motive liquid enters the motive chamber of the Jet Mixer through a converging motive nozzle. At the jet nozzle, the pressure energy of the motive liquid is converted into a high velocity jet. The momentum present in the motive liquid is transferred to the suction liquid thereby enabling a LIFT, entrainment and mixing. Thus the high velocity motive liquid mixes with the suction liquid.

Jet Mixer Sizing
Jet Mixer diameter and no. of jets to be installed totally depends on L/D ratio of vessel/storage tank. Once these parameters define, then nozzle diameter can be calculated by assuming jet velocity and a typical value would be 10 m/sec. for turbulent flow. For Laminar Flow velocity should be greater than 10 m/sec to achieve plume to reach surface level. Followed by the pressure drop and pump flow rate. The jet nozzle should be constructed from standard pipe.