Established in 1994, Mohawk Innovative Technology, Inc. (MiTi®) is the world’s leading authority in developing oil-free, high-speed rotating machinery employing compliant foil air bearing technologies. MiTi® has developed a family of CleanTech, high efficiency, oil-free rotating machinery products that include renewable energy turbogenerators, oil-free turbocompressors/blowers and electric motors.
Motors
MiTi® has developed a family of 5 to 200 HP high-speed permanent magnet or induction motors with operational speeds ranging up to 180,000 rpm. Each motor uses MiTi® airfoil bearings, high power density motor elements and a VFD to provide motors with efficiencies greater than 95%. Because MiTi® oil-free airfoil bearings are used, no auxiliary lubrication supply system is needed, eliminating maintenance and hazardous waste disposal issues. Efficiency gains of from 30-35% over medium sized, high-speed motors using oil-lubricated bearings have been demonstrated. The VFD permits a wide operating speed range and precise speed control. As with our other products, the single moving part and MiTi® bearings assure long life and low maintenance in a compact package. Custom designs requiring higher power levels and speeds to meet special needs are available.
Compressors and Blowers
MiTi® blowers, ranging from 5 HP to 200 HP, are designed to use high-efficiency, high-speed permanent magnet motor elements, MiTi® patented 6th Generation airfoil bearings, advanced impellers and controllers for variable speed operation. The single integrated motor, impeller and oil-free bearing system increases life, and reduces maintenance costs and machine footprint. Wide operating speed range demands are achieved with sensorless variable frequency drives. Long life in a compact, lightweight and quiet package. Low starting and operating currents, made possible by MiTi® foil bearings, reduce operating and maintenance costs as well as greenhouse gas emissions. Since absolutely no oil is used in MiTi® blowers, environmental hazards and waste disposal issues are eliminated. Because MiTi® blowers and compressors are absolutely oil-free, they can be customized to work with many different process gases. When used with fuel cell stacks, contaminant free compressed air or hydrogen is supplied.
Turbogenerators
MiTi® has developed a series of the world’s first completely oil-free turbomachinery using compliant foil bearings, ranging from turbochargers to turbine engines and pipeline class hydrogen compressors. The low power-loss and lubricant-free foil bearings overcome contamination, drag, speed and temperature limitations associated with other machine bearing designs to increase responsiveness, efficiency and durability. Premature bearing failures due to high speed and high operating temperatures are eliminated. Oil supply and scavenge lines are also eliminated, resulting in simplified installations, reduced oil leak potential and lower part count.
MiTi® turbogenerators are very high efficiency, turbine powered electric generator systems for use with either conventional fuels or renewable energy sources including solar, waste heat or wind. Low operating and maintenance costs are due to the integrated assembly of an advanced turbine drive, an efficient high-speed, 4-pole permanent magnet generator rotor and MiTi® compliant foil bearings. Having only one moving part that is supported on a film of process gas increases machine reliability and durability. Long product life is achieved because there is no contact between the bearing and shaft during operation. This product can also be used for combined energy and refrigeration systems. Environmental hazards associated with the use and disposal of lubricating oils are eliminated with MiTi®’s compliant foil bearings and potential for hermetic sealing is increased. Power ranges from ½ to 200 kW have been designed or are in development.
Air-Cycle Machines
MiTi® has designed and tested an Air-Cycle Machine (ACM) for advanced fighter aircraft, as well as other potential applications. The MiTi ACM operates at speed of 120,000 rpm, 20% higher than completing technology, allowing for a reduction in weight and size envelope. The machine features MiTi®’s low power loss compliant foil bearings that do not require an additional cooling feed at the thrust bearing outer diameter, as in the case of other OEM designs currently in the field. This reduced cooling flow creates greater machine efficiency and lower likelihood of bearing contaminants from dust and debris.
ORC Turboalternators
MiTi has two main families of ORC Turboalternators. Our high speed axial turbine engines, are characterized by relatively flat adiabatic efficiency curves under a broad range of specific speeds, making them ideal for use in highly variable environmental conditions, as in geothermal sites, or where condensation temperatures fluctuate widely with the seasons. Our radial inflow devices exhibit a high single stage power density, and accommodate larger flow rates at lower spin speeds, which may be preferable for industrial applications with steadier operating conditions.