Diffuser efficiency
US5129119A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 9, 1991 |
| Grant date | Jul 14, 1992 |
| Priority date | — |
| Expiry date | Apr 9, 2011 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21D5/02
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
The efficiency of a diffuser, for washing or bleaching paper pulp, is enhanced by taking steps to ensure that the approximate upstroke speed is only slightly faster than the pulp upflow velocity, to provide an early warning indication of the tendency of the diffuser screens to plug, and to prevent upward movement of the screen, after completion of a downstroke, uncontrolled by the hydraulic system designed to effect movement. The pressure under the annular screen is sensed and compared to normal static pressure at the elevation of the screen by a D/P cell in a leg, and a computer controls the hydraulic system so that the screen upstroke speed is only slightly faster than the pulp upward speed. Early detection of a tendency to plug is provided by a pressure sensor within the hollow interior of the screen spaced from the screen orifices. To prevent gas from pushing the screen upwardly, during an initial part of an upstroke, the hydraulic system is operated to effect quick upward movement a small predetermined distance before continuous, smooth movement is effected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.