What Type of Blade Works Best on My Disperser?

What Type of Blade Works Best on My Disperser?

High-shear disperser blades are available in a range of styles and sizes (Figure 4). They can be generally categorized into two groups, open saw tooth and ring-type. Both categories work well when used under the proper operating conditions.

The open saw tooth blade is the most popular because of its low cost, ease of cleaning, and general utility. It is available in a wide range of tooth design. As the teeth increase in size and become more aggressive in shape, the pumping ability of the blade increases. However, as pumping (turbulent flow) increases, shear decreases. A high pumping saw blade still generates significant shear compared to a low shear paddle blade agitator. This aspect is an important consideration when determining exactly what is to be achieved in the finished product.

The ring-type blade is a powerful tool for optimizing disperser performance. It is more expensive to purchase and consumes more horsepower than the saw blade. It typically runs at higher tip speeds (5700 + fpm) and performs more like a rotor stator. Instead of solely depending upon the face of the disc and the configuration of the saw-tooth for shear and flow, much of the ring blade’s work is done hydraulically as centrifugal force forces the product between the contoured rings creating velocity differentials and a high pressure zone within and then instantaneously discharging into the low pressure area outside the rings, creating a film-splitting venturi effect. Additional heat is created as a by-product of the higher shear. However, in some cases, this higher shear level eliminates or greatly reduces any subsequent milling that may have previously been required.