Method and apparatus for enhancing filter bed performance

US6890440B2 · kind B2 · utility

Assignee

• NBE, LLC · US

Inventors

• Dennis Chilcote · Hibbing, US
• Mike S. Gratz · Eden Prairie, US
• Robert E. Clifford, III · Eden Prairie, US
• John Mills · Eden Prairie, US
• Gregory Vineretsky · Eden Prairie, US
• Daniel McGraw · Eden Prairie, US
• Alan Dunn · Eden Prairie, US
• Bobby Dabbs · Humboldt, US
• Karie Mars · Shoreview, US

Key dates

• Filing date: Aug 1, 2003
• Grant date: May 10, 2005
• Expiry date: Aug 1, 2023

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D24/46
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

In a vessel containing a filter bed and containing a mixed liquor containing suspended solids, a system disturbs/dislodges a sludge mat that settles on the filter bed. Thus, the system controls the sludge mat on the filter bed that otherwise may blind the filter bed and significantly reduce or stop process liquid flow into and through the filter bed. The system helps maintain effective vessel effluent flowrates with reduced requirements for filter bed backwashing or other filter bed maintenance. The system includes a sludge mat dislodging member that moves along the filter bed surface, preferably on but substantially not inside the filter bed, to disrupt/dislodge the sludge mat and/or prevent formation of the sludge mat. Preferably, the dislodging member is carried inside the vessel on a moving arm or arms that rotate in a plane parallel to the filter bed surface. The preferred sludge mat dislodging member(s) hang from the rotating arm(s) to slide along the top of the filter bed through the sludge mat. The sludge mat control methods and apparatus preferably are used during normal operation of the reactor/vessel, without requiring shutdown or interruption of the process. The methods…