Vertical pulping digester having substantially constant diameter
US5985096A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 23, 1997 |
| Grant date | Nov 16, 1999 |
| Priority date | — |
| Expiry date | Sep 23, 2017 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21C7/00
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
In a vertical digester for producing chemical pulp, or other vessel for treating a slurry of comminuted fibrous cellulosic material, the cost of manufacturing the shell is significantly reduced by eliminating the external step increases in the digester shell. The digester shell has a substantially constant internal diameter from just below the inlet to just above the outlet, screen assemblies being provided by an internal transition (e.g. conical) having an angle of convergence of less than 40.degree. (e.g. about 10-25.degree.) above each screen assembly so that the slurry flows through the transition without bridging or hang-up, and a step increase, or other increase, in diameter back to the first diameter after the screen assembly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.