Method and apparatus for producing microshells
US5055240A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 1986 |
| Grant date | Oct 8, 1991 |
| Priority date | — |
| Expiry date | Apr 30, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29B2009/125
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method is described for forming hollow particles, or shells, of extremely small size. The shell material is heated to a molten temperature in the presence of a gas that is at least moderately soluble in the shell material, to form a solution of the molten shell material and the soluble gas. The solution is atomized to form a multiplicity of separate droplets that are cooled while in free fall. Cooling of a droplet from the outside traps the dissolved gas and forces it to form a gas bubble at the center of the droplet which now forms a gas-filled shell. The shell is reheated and then cooled in free fall, in an environment having a lower pressure than the gas pressure in the shell. This causes expansion of the shell, to form a shell having a small wall thickness compared to its diameter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.