Method and apparatus for producing concentric hollow spheres

US4279632A · kind A · utility

Inventors

• Robert A. Administrator of the National Aeronautics and Space Frosch · La Cañada Flintridge, US
• Taylor G. Wang · Glendale, US
• Daniel D. Elleman · San Marino, US

Key dates

• Filing date: May 8, 1979
• Grant date: Jul 21, 1981
• Expiry date: May 8, 1999

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S376/916
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Hollow spheres with precisely concentric inner and outer spherical surfaces are formed by applying vibrations to a nonconcentric hollow sphere while it is at an elevated temperature at which it is fluid or plastic, the vibrations producing internal flows which cause the inner and outer surfaces to become precisely concentric. Concentric spheres can be mass produced by extruding a material such as glass or metal while injecting a stream of gas into the center of the extrusion to form a gas-filled tube. Vibrations are applied to the extruded tube to help break it up into individual bodies of a desired uniform size, the bodies tending to form spherical inner and outer surfaces by reason of surface tension, and the continuing application of vibrations causing these surfaces to become concentric.