Richard D Maxson

US Patent:

51184192, Jun 2, 1992

Filed:

May 13, 1991

Appl. No.:

7/698900

Inventors:

Thomas W. Evans - Houston TX
Robert G. Norell - New Brighton MN
Stephen A. Uban - Stillwater MN
Richard C. Maxson - Maple Grove MN

Assignee:

Johnson Filtration Systems Inc. - New Brighton MN

International Classification:

B01D 2124

US Classification:

210291

Abstract:

An underdrain assembly for a bed of filter media includes a plurality of elongated screen lateral elements which each have a generally flat bottom surface and a convexly curved upper surface which has flow openings therein. The lateral elements each have a width substantially greater than their height and include a means defining a generally tubular-shaped surface positioned internally thereof. The generally tubular-shaped surface includes flow distribution openings which have a total open area less than the total area of the flow openings in the curved upper surfaces of the lateral elements. In various embodiments, the generally tubular-shaped surfaces are shown as comprising a single tube, a plurality of tubes, and a tube defined by the portions of a plurality of adjacent channel-shaped members whose leg portions support the curved upper surface of the screen lateral elements.

US Patent:

50153838, May 14, 1991

Filed:

Jun 15, 1989

Appl. No.:

7/366872

Inventors:

Thomas W. Evans - Houston TX
Robert G. Norell - New Brighton MN
Stephen A. Uban - Stillwater MN
Richard C. Maxson - Maple Grove MN

Assignee:

Johnson Filtration Systems Inc. - New Brighton MN

International Classification:

B01D 2900

US Classification:

2104971

Abstract:

An elongated screen assembly, which in various forms, is useful as a scallop in a reactor, or as an underdrain for a gravity filter system, has a cross-section in a direction normal to its axis which is at least twice as wide as it is high. A method is also disclosed for manufacturing the screen assembly by pressing the opposed sides of a wrapped wire cylindrical screen assembly between a pair of plates which have radii of curvature which are different from each other and greater than the radius of curvature of the cylindrical screen assembly.