Headquartered in Hanover, Massachusetts, Sturtevant Inc. is a family-owned manufacturer of materials processing equipment, including crushers, fine grinders and air classifiers. Since 1883, the company has provided processing solutions to the chemical, pharmaceutical, foods and mineral processing industries. Founded by Thomas L. Sturtevant, the company is currently managed by W. Sturtevant English, Jr., the fifth generation from the company’s founder.

Air Classifiers

Sturtevant - Whirlwind SepSolA Sturtevant Air Classifier balances the physical principles of centrifugal force, drag force and gravity to generate a high-precision method of classifying particles according to size or density. For dry materials of 100 mesh and smaller, air classification provides the most effective and efficient means for separating a product from a feed stream for de-dusting, or for increasing productivity when used in conjunction with grinding equipment. All three Sturtevant air classifiers offer durable construction, as well as time- and energy-saving advantages.

Whirlwind Air Classifier

The Whirlwind® Air Classifier incorporates a self-contained fan and rejector blade classification system. Its internal fan design does not require cyclones, air locks or dedicated bag-house for product collection of particles in the range of 100 to 400 mesh. Completely self-contained, requires no process dust-collection equipment.

Whirlwind Mobile Air Classifier

The Whirlwind® Mobile Air Classifier is the world’s first and only 100% mobile air classifying plant with integral collapsible conveyors.

The Whirlwind® Mobile Air Classifier effectively removes excess fines from aggregate products bringing materials formerly considered waste materials into specification. The Mobile Air Classifier’s dry separation process eliminates the need for water typically used in washing plants, which is especially important in remote areas where water is not readily available.

The Whirlwind® Mobile Air Classifier is easy to transport with a rugged chassis frame and a heavy-duty tri-axle suspension. The Whirlwind® Mobile Air Classifier has three conveyors that hydraulically fold for transport and unfold for set-up. Raising and lowering of the air classifier is accomplished with heavy-duty dual hydraulic cylinders for easy and safe set-up and tear down. See the Whirlwind® Mobile Air Classifier in action.


FCM Air Classifying Mill

The FCM Classifier Mill is a high speed impact mill with an internal air classifier. The material enters the grinding chamber through the feed inlet where it comes into contact with a series of spinning impact pins or blocks smashing the material into fine particles. The fine particles must pass through a cage of spinning blades, known as the “classifier wheel”. The wheel acts as a screen and only lets the particles that are small enough to pass through, it also rejects the large particles causing them to stay in the mill for additional grinding. The fine particles then exit the mill and are collected in a bag house product collector. Particle size is easily adjusted by increasing or decreasing the classifier speed, without mill shutdown to achieve the desired PSD. Other system parameters are easily adjusted to allow for tight control of product size for grinding and classifying of a variety of materials.

• Combines impact milling and air classification technologies
• Air swept design prevents heat build up
• Low operational and maintenance costs
• Machine can be easily disassembled for cleaning and servicing
• Easily adjust PSD for efficient milling
• No screens to blind or tear

The FCM Air Classifier is a classifying impact mill capable of reducing powders down to 10 microns. It is fast becoming the workhorse in particle size reduction applications due to its combination of impact milling and air classification technologies in a single unit. The FCM’s flexibility of operation allows it to easily process a multitude of product categories requiring efficient and economical particle size reduction for a broad range of industries including pharmaceutical, food, chemical, mineral and others.

Micronizer® Jet Mill

Sturtevant Micronizer Jet MillInventing the Micronizer® jet mill over 60 years ago makes Sturtevant both the worldwide expert in fluid energy milling as well as the most popular choice for this technology worldwide.   No company has sold and engineered more fluid energy mills than the Micronizer® by Sturtevant.  The Micronizer® operates by particle-on-particle attrition to grind without the introduction of heat or wear into the grinding process and is capable of particle reduction to 250nm.

The Sturtevant Micronizer® is a jet mill (fluid energy mill) employing compressed air or gas to produce particles less than one micron. Inside the Micronizer, precisely aligned jets create a vortex. Material is fed into this vortex along an engineered tangent circle and accelerates. High-speed rotation subjects the material to particle-on-particle impact, creating increasingly smaller fines. While centrifugal force drives large particles toward the perimeter, fine particles move toward the center where they exit through the vortex finder.

  • No dead zones to trap material, no moving parts to wear, no grinding media or lubrication to contaminate milled products
  • One step grinding and classifying in a continuous or batch process

Simpactor® Pin Mill

Sturtevant - Simpactor SepSolDesigned to use varying degrees of impact and agitation to process materials, the Sturtevant Simpactors® are among the most versatile equipment available in the materials processing industry. From high-impact grinding at top speeds of 45,000 feet per minute to controlled slower RPM mixing and blending, pin mills are easy to operate, highly reliable, safe and simple to adapt for applications. The Sturtevant Simpactor® Pin Mill is a centrifugal, pin-type impact mill, reduces low-to-medium-density materials to uniform fine particle size of 50-200 mesh.

  • High Speed Impact Pin Mill
  • Mesh Product without Screens
  • Highly Versatile—Simple Operation

Fine Grinding And Air Classification Product Lines

Product Lines

  • Micronizer ® – Jet Mill
  • Air Classifiers
  • Simpactor ® – Pin Mill
  • FCM Air Classifying Mill
  • Hammermills
  • Roll Crushers
  • Jaw Crushers
  • Rotary Crushers
  • Sample Grinders


  • Aggregates, Crushed Stone
  • Agricultural Chemicals
  • Carbon Black
  • Ceramics
  • Chemicals
  • Clay
  • Cocoa
  • Cornstarch
  • Corn Slurry
  • Deagglomeration
  • Densification
  • Diatomaceous Earth
  • And more…