How to Select a High Speed Disperser

A few rules of thumb to consider when sizing a Single Shaft - High Speed Disperser

1. Viscosity make sure the viscosity is such that it can be mixed using a single shaft mixer. The materials are usually within a upper viscosity range of 50,000 centipoise. The materials are ideally thixotropic (shear thinning) and flow well under shearing/mixing conditions

2. Volume Determine the volume of product required to meet your production forecasts. Establish the optimum batch size to match your facilities and available personnel.

3. Vessel design The optimum vessel design is one that is round with a dished bottom. This design promotes good flow and minimizes the possibility of dead spots where unmixed materials can collect. A flat or sloped bottom is also typical. In general, a vessel that is approximately the same diameter and height is preferred for use with dispersers. Please allow for vortexing of the product by having the side walls of the vessel at 30% (freeboard) above the full batch level when the product is at rest. The dispersion blade is normally positioned .5 of the blade diameter off of the vessel bottom. The vessel diameter should be 3x the blade diameter. The full batch level at rest should be 1.5 blade diameters above the blade.

4. Disperser size and speed The blade diameter should be roughly 1/3rd the diameter of the vessel. Power consumption will be determined by the diameter of the blade, the density of the formulation, and the speed at which the blade turns. A typical disperser is sized in the range of 10 HP per 100 gallons of product to be mixed. Normal blade is speed is in the 4800 - 5200 fpm (feet per minute) range.

Standard High Shear High Tooth Blade
Type 1 - Standard High Shear
The most popular blade for coatings dispersion. Balances high shear dispersion with pumping action.

Type 2 - High Vane Blade
High pumping action. Mixes an entire batch with minimal shear and heat buildup. Popular in the mixing and letdown of coatings.

Cutter Style High Vane Style
Type 3 - Cutter Style
Offers a combination of high shear along with excellent batch movement. Excels in high viscosity and high solids batches.

Type 4 - High Tooth Style
High pumping action. Mixes an entire batch with minimal shear and heat buildup. Popular in the mixing and letdown of coatings

Poly-Blade  
Type 5 - Poly-Blade
Made from Ultra-High Molecular Polyethylene for superior wear. Effective in highly abrasive applications.