Characterizing the performance of dental air-turbine ...
2008-1-1 · Patented designs continued to appear, including finger-operated air and water coolant valves, and needle roller bearings for the rotor which acted as the turbine blades. 51 The ball bearings initially used were noisy, required continuous oil-mist lubrication, and wore out rapidly. 50, 52, 53 Air bearings, introduced in the early 1960s, permitted speeds up to 528 000 rpm (8800 /s) to be achieved with air at …
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