Paul Mueller Company Academy

How to Choose the Best Agitator for Your Milk Silo

Agitators contain different parts such as bearings, seals and couplings but there are three in particular you should consider when purchasing one. The shaft, blade and motor are three essential parts that require different considerations for every purchase. Different product types and production needs will dictate what combination of these three parts you choose.

Vertical or Horizontal Shaft

Should you install your agitator with the shaft vertical from the top or horizontally from the side? The answer depends on a variety of factors. Generally, horizontal agitators are used for larger tanks while vertical ones work well for smaller ones. The vertical agitator works by exerting downward force on the liquid while horizontal agitators typically work by driving the liquid along straight paths along the bottom of the tank then upward. One of the reasons a food processor might choose horizontal agitators is due to the reduced risk of sheering the product. Vertical agitators have to spin faster to push the liquid to the bottom of the tank so the increased speed may run the risk of deteriorating some of the solids instead of evenly distributing them.

Blade Type

A few common types of agitator blades in the food processing industry include propeller, anchor and paddle blades. The blade type depends on the type of product you are trying to agitate. Molasses will have a different viscosity and density than milk which will require a different type of blade to be installed.  Some blades will require more energy to operate but this is not necessarily a negative as your particular product may not agitate well with smaller blades. Your product, tank size and processing goals each play a role in determining how to choose you blade.


The choice of an agitator motor is similar to the blade – you must take your product, tank size and processing goals into consideration. There are also a few more things to consider. How much of a load cushion are you allowing for your motor? Are you installing one that will need to use 100% of its load capacity or less? Running a motor at a full load will reduce its efficiency so you should install a motor with a little more power than the load would dictate. You should also consider whether the volume of product within your tank will vary. If you are utilizing less than full capacity in your tank, then the settings on your motor should be adjusted accordingly.


When choosing an agitator, it would be wise to ask yourself what your unique circumstances are and to make a purchase based on that. A good vendor will help walk you through the process and ask question without presuming to know the answer. Click here to chat with one of our experts today.

Topics: Food and Dairy Processing Equipment

About Paul Mueller Company Academy

Teaching and sharing ideas has long been part of the rich heritage at Paul Mueller Company. We have almost a century of quality craftsmanship guiding the way we apply new learnings. Paul Mueller Company Academy is a collection point for those learnings, so we can collaborate and grow more successful together. You will find articles, blogs, guides, infographics and more dedicated to furthering knowledge for all, in the world of stainless steel processing equipment solutions. We hope you enjoy!