Pyrolytic deposition in a fluidized bed
US5284676A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 18, 1991 |
| Grant date | Feb 8, 1994 |
| Priority date | — |
| Expiry date | Nov 18, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2235/5427
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Precise control of pyrocarbon being coated upon an object in a fluidized particle bed is achieved by monitoring the pressure difference between a region above the bed and a region in the lower portion of or just below the bed. Measurement of such pressure differential has been found to be truly representative of bed size in such a coater, and bed size is recognized to be a most important factor in achieving the desired characteristics of the substance being deposited. By adjusting bed size in response to changes in the pressure difference being monitored, a substantially constant bed size is readily achieved; alternatively, the pressure difference can be caused to gradually change in accord with a predetermined program. In either instance, adjustments are effected by adding additional particles to the bed or by changing the rate at which particles are withdrawn, and precise coating characteristics, e.g. thicknesses within very close tolerances, are achievable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.