Scalable impeller apparatus for preparing silver halide grains
US6422736B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 2000 |
| Grant date | Jul 23, 2002 |
| Priority date | — |
| Expiry date | Jun 21, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01F27/91
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A mixer for preparing silver halide grains for photographic use has upper and lower impellers housed in a draft tube. The bottom impeller has flat blades for micromixing silver and halide reactants introduced into the bottom of the draft tube. The upper impeller has pitched blades for macromixing the bulk fluid. The impellers are spaced apart at least the distance of their diameters so that the upper and lower impellers operate independently of one another so that micromixing is independent of macromixing. A flow disrupter structurally associated with the draft tube and positioned above the top impeller prevents vortexing of the fluid during mixing. Baffles may be provided in the draft tube to discourage vortexing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.