Headquartered in Massachusetts, USA, Sturtevant Inc. is a family-owned manufacturer of material processing equipment including crushers, fine grinders and air classifiers.  Since 1883, the company has provided processing solutions to the chemical, pharmaceutical, food and mineral powder processing industries worldwide.

The test facility in Hanover, Massachusetts is capable of milling or air classifying dry solids.  Every step of the way, qualified laboratory technicians will optimize customer’s equipment capacity and communicate wear-protection and material-handling requirements.

Sturtevant's service technicians are available to assist in the installation and start-up of new equipment.  In addition, when needed, qualified Sturtevant service technicians will provide comprehensive field inspections to evaluate equipment condition and recommend adjustments and/or parts replacement.  Manufactured to strict original factory specifications, Sturtevant's OEM replacement parts ensure safer operation with less downtime and carry full factory warranties.  Service capabilities include the rebuilding and remanufacturing of entire machines or sub-assemblies to original factory specifications should that become necessary.

Sturtevant offers a full line of size reduction equipment.  From large coarse particle crushers to the patented sub-micron Micronizer®, Sturtevant custom engineers units suited to the widest range of applications.  If an operation requires particle separation through air classification, Sturtevant produces three different kinds of air classifier systems.

The Whirlwind Air Classifier incorporates an internal fan and rejecter blade classification system. Its self-contained design does not require cyclones, valves, dampers, ductwork, external fan or the additional supports required to handle these components. The feed is belt conveyed into the Whirlwind Air Classifier by gravity. The dedusted manufactured sand exits the Whirlwind Air Classifier by gravity for belt conveying to the clean pile. The dry minus 200 mesh fines also exit the Whirlwind Air Classifier by gravity for belt conveying to a fines by-product pile. Entire flow of fines discharges from one single easy to manage outlet, instead of multiple locations.
The rotating selector blades control the particle size of the fines removed by the air. This improves the dedusted product yield, when compared to static air classifiers. The selector blades also maintain or exceed fines product specifications, when sold as a secondary product.

The Whirlwind Air Classifier offers an exceptional ability to achieve a wide range of separations. Its features allow precise definition of the desired size product while delivering the following benefits:

- No water required
- No settling ponds or land restoration
- Lowest capital cost: no auxiliary equipment is needed, such as baghouse, screen, cyclones, process dust collectors, air locks, and system fans
- Consistent, high-quality product
- Saves on operating expenses:
   - Low energy consumption
   - Low maintenance and proven long life span
- Processes abrasive materials using long-wearing, inexpensive replaceable liners
- Sell dry fines for Ag lime or fillers
- Ideal for superpave applications

Stone Aggregate entering through the feed spout is subjected to centrifugal force, throwing coarse particles away from the distributing plate and into the air flow. Due to gravity, large particles settle into the coarse cone. Finer particles are swept upward where selector blades generate further classification. During this secondary separation, oversized particles are spun out of the air flow and drop down into the coarse cone. The selected fines continue through the circulating fan and into the fines cone. Fines drop out the recirculated air flow at the fixed return air vanes.

Coarse discharge represents the dedusted stone. Fines discharge represents the dust removed.