Method for producing small hollow spheres
Abstract
A method for producing small hollow spheres of glass having an outer diameter ranging from about 100.mu. to about 500.mu. with a substantially uniform wall thickness in the range of about 0.5-20.mu.. The method involves introducing aqueous droplets of a glass-forming solution into a long vertical drop oven or furnace having varying temperature regions. In one embodiment, one of the temperature regions is lower than both the preceeding region and the subsequent region. One region utilizes a temperature of at least 200.degree. C. higher than the melting point of the glass-forming material in the solution and, for example, may be at least 3 times higher than the temperature of the preceeding region. In addition, there is a sharp temperature gradient between these regions. As each droplet of solution passes through a first region it forms into a gel membrane having a spherical shape and encapsulates the rest of the drop retained in the elastic outer surface and the water entrapped within diffuses rapidly through the thin gel membrane which causes more of the glass-forming material to go out of solution and is incorporated into the gel membrane causing it to grow in size and become hollow. thus produced hollow glassmore »
- Inventors:
-
- Danville, CA
- San Ramon, CA
- Spring Valley, OH
- Issue Date:
- Research Org.:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- OSTI Identifier:
- 863834
- Patent Number(s):
- 4257799
- Assignee:
- United States of America as represented by United States (Washington, DC)
- Patent Classifications (CPCs):
-
C - CHEMISTRY C03 - GLASS C03B - MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
C - CHEMISTRY C03 - GLASS C03C - CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS
- DOE Contract Number:
- W-7405-ENG-48
- Resource Type:
- Patent
- Country of Publication:
- United States
- Language:
- English
- Subject:
- method; producing; hollow; spheres; glass; outer; diameter; ranging; 100; 500; substantially; uniform; wall; thickness; range; 5-20; involves; introducing; aqueous; droplets; glass-forming; solution; vertical; drop; oven; furnace; varying; temperature; regions; embodiment; preceeding; region; subsequent; utilizes; 200; degree; melting; material; example; times; addition; sharp; gradient; droplet; passes; forms; membrane; spherical; shape; encapsulates; retained; elastic; surface; water; entrapped; diffuses; rapidly; causes; incorporated; causing; grow; size; produced; sphere; sphericity; concentricity; uniformity; capable; retaining; atmospheres; therein; periods; time; spherical shape; hollow spheres; wall thickness; temperature gradient; method involves; outer surface; substantially uniform; hollow glass; outer diameter; produced hollow; forming material; uniform wall; method involve; hollow sphere; solution pass; /65/264/376/501/
Citation Formats
Rosencwaig, Allen, Koo, Jackson C, and Dressler, John L. Method for producing small hollow spheres. United States: N. p., 1981.
Web.
Rosencwaig, Allen, Koo, Jackson C, & Dressler, John L. Method for producing small hollow spheres. United States.
Rosencwaig, Allen, Koo, Jackson C, and Dressler, John L. Thu .
"Method for producing small hollow spheres". United States. https://www.osti.gov/servlets/purl/863834.
@article{osti_863834,
title = {Method for producing small hollow spheres},
author = {Rosencwaig, Allen and Koo, Jackson C and Dressler, John L},
abstractNote = {A method for producing small hollow spheres of glass having an outer diameter ranging from about 100.mu. to about 500.mu. with a substantially uniform wall thickness in the range of about 0.5-20.mu.. The method involves introducing aqueous droplets of a glass-forming solution into a long vertical drop oven or furnace having varying temperature regions. In one embodiment, one of the temperature regions is lower than both the preceeding region and the subsequent region. One region utilizes a temperature of at least 200.degree. C. higher than the melting point of the glass-forming material in the solution and, for example, may be at least 3 times higher than the temperature of the preceeding region. In addition, there is a sharp temperature gradient between these regions. As each droplet of solution passes through a first region it forms into a gel membrane having a spherical shape and encapsulates the rest of the drop retained in the elastic outer surface and the water entrapped within diffuses rapidly through the thin gel membrane which causes more of the glass-forming material to go out of solution and is incorporated into the gel membrane causing it to grow in size and become hollow. thus produced hollow glass sphere has a sphericity, concentricity, and wall uniformity of better than 5%. The sphere is capable of retaining material of up to at least 100 atmospheres therein over long periods of time. In one embodiment.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jan 01 00:00:00 EST 1981},
month = {Thu Jan 01 00:00:00 EST 1981}
}