Multi-stage filtration and softening module and reduced scaling operation
US6702944B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 2001 |
| Grant date | Mar 9, 2004 |
| Priority date | — |
| Expiry date | Jun 29, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F1/442
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A filtration module has at least one nanofiltration or reverse osmosis membrane. The module is used to filter water and, when optionally fitted with at least one membrane adapted to selectively reject hardness causing salts, is used to remove hardness. Methods of cleaning using acidic solutions or gaseous carbon dioxide are discussed. Cleaning methods include the steps of periodically stopping permeation, injecting an acidic solution or gaseous carbon dioxide into the feed/retentate side of the module, holding the acidic solution or gaseous carbon dioxide in the module for a selected time, and flushing the acidic solution or gaseous carbon dioxide from the feed/retentate side of the module after expiration of the selected time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.