Low pressure filtration
US7585411B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 2006 |
| Grant date | Sep 8, 2009 |
| Priority date | — |
| Expiry date | Aug 22, 2027 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D2321/185
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
High flow, low-pressure ultrafiltration or microfiltration spiral wound membrane cartridges are used in filtration of liquid feedstocks having high suspended solids. Applications may utilize either vacuum or pumping for transmembrane drive pressure (TMP), and gas may optionally be bubbled up through the cartridges with certain feedstocks. Water permeate flux rates as high as 90 gallons per square foot per day (gfd) can be obtained at TMPs below 5 pounds per square inch. By locating each spiral wound cartridge in its own casing and supplying liquid feedstock to an open lower end of the casing, as opposed to submerging such cartridges in a tank filled with feedstock, overall low pressure performance is greatly improved. High permeate flow can be maintained for long periods of time between shutdowns for intensive cleaning. TMP is gradually increased to maintain a substantially constant rate of permeate discharge until a target is reached, indicative of solids accumulation on the membrane surface to an undesirable extent; then backflushing is effected for a short time. Discarding the hold-up volume of feedstock in the cartridge, the backflushing fluid and dislodged solids, allows produ…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.