System for controlled acoustic rotation of objects

US4393706A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventor

• Martin B. Barmatz · La Cañada Flintridge, US

Key dates

• Filing date: Sep 18, 1981
• Grant date: Jul 19, 1983
• Expiry date: Sep 18, 2001

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16C32/00
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

A system is described for use with acoustically levitated objects, which enables close control of rotation of the object. One system includes transducers (18, 20, 22) that propagate acoustic waves along the three dimensions (X, Y, Z) of a chamber (16) of rectangular cross section. Each transducer generates a first wave which is resonant to a corresponding chamber dimension to acoustically levitate an object, and additional higher frequency resonant wavelengths for controlling rotation of the object. The three chamber dimensions and the corresponding three levitation modes (resonant wavelengths) are all different, to avoid degeneracy, or interference, of waves with one another, that could have an effect on object rotation. Only the higher frequencies, with pairs of them (e.g. 50, 52) having the same wavelength, are utilized to control rotation, so that rotation is controlled independently of levitation and about any arbitrarily chosen axis.