Understanding How Tank Geometry Affects Industrial Mixing

Much thought goes in to selecting the right industrial mixer. There's the question of how to mount it, how much power it should have, and a myriad of other questions surrounding the impeller(s). The mixer is important to achieving process goals (obviously), but just as important is the tank's design.

Tank Geometry

Each type of tank has its advantages and disadvantages in terms of structure, price, and effectiveness. The most common types of tank designs are square or rectangular, and cylindrical tanks. Tanks can also have different geometries on the bottom. These can include flat, rounded, or conical. We'll cover the advantages and disadvantages of these in a later post.

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Square or Rectangular Tanks

According to Sean Donkin, from Cleveland Mixer, one of the great things about square/rectangular tanks is that the corners of the tank act as baffles, allowing for the transfer of the agitator's power to be invested more effectively in the liquid.

A disadvantage to square or rectangular tanks, however, is that the fabrication costs may not be as competitive as a cylindrical tank. Also, they are not recommended for solids suspension because solids can build up in the tank's corners.

Cylindrical Tanks

Cylindrical tanks tend to have stronger design, but will typically require baffles when the mixer is centered in the tank and vertically mounted. Mixing without baffles in this situation results in a swirling motion that results in vortexing and little to no mixing at all.

Keep in mind, viscosity plays a role in this scenario as well. Low viscosity fluids will most likely require baffles, but high or medium viscosity may not, due to the fact there may be enough resistance for the mixer to impose all of its torque on the fluid.

Excellent mixing results can be achieved with a square, or cylindrical tank. Just make sure to alert your application engineer early in the process if you'll be needing a new tank for your application. If you have an existing tank, share this with the application engineer. They can ensure the mixer works with the tank to achieve your process goals.

Need help selecting a tank and/or mixer? Ask us about it! We gladly provide technical assistance to businesses and municipalities in Wisconsin and upper Michigan.