Tuthill Vacuum & Blower Systems
Manufacturer of rotary piston, liquid ring, dry and rotary vane vacuum pumps, and rotary positive blowers for industrial and trucking applications. Based in the US (IL).
http://vacuum.tuthill.com/

Orbiting Piston
Patented, innovative rotary internal combustion engine which orbits instead of rotates and has piston like chamber action. Includes theoretical and technical background, specifications, diagrams and patent.
http://home.woh.rr.com/opengine

Combined Fluid Products
Vacuum pumps: Combined Fluid Products offers vacuum pump, vacuum pumps, air knife, air knives, and air knife drying.
http://www.combinedfluidproducts.com/

Zilli Bellini srl
Gravity, rotary, and piston filling equipment.
http://www.zilli-bellini.com/

Burton Corblin
Manufacturer of diaphragm, piston and rotary Periflow compressors.
http://www.burtoncorblin.com/

T.H.E. Electric Motor Company
The Electric Motor Company - recognised supplier of motors, pumps, gearboxes, motion control equipment and commutators to the Beverage, Mobility, Industrial and Leisure markets
http://www.the-motorco.com/

Bergner Metalurgica
Manufacturer of compressor (piston type) spare parts: Valves, piston rod packings, scraper rings, PTFE piston rings, for Ateliers Francois, ABC, Belliss and Morcom and other compressors.
http://www.bergner.com.ar/

Pneumofore
Vacuum pumps and air compressors for industrial applications. Leader in rotary vane technology. Centralized vacuum pumps systems and air compressors, Pneumofore delivers solutions for demanding requirements of industrial vacuum and compressed air.
http://www.pneumofore.com/

Antonio Sanchez Engineering
Motor hibrido rotativo - reciproco de cilindros y embolos rotativos / Hybrid engine rotary and reciprocates with rotary cylinders and pistons
http://www.geocities.com/CapeCanaveral/2542/seceng.html

Daniel Valve Company
Provides slab and expanding pipeline gate, axial and rotary control, piston, swing and wafer check valves.
http://www.danielvalve.com/