The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 17, 2004
Filed:
Jun. 28, 2002
Gary D. Haggard, Austin, TX (US);
Enviroquip, Inc., Austin, TX (US);
Abstract
An underdrain filtration system has improved perforation structure, the perforations being positioned to admit the filtrate into a plenum defined by elongated underdrain rib structures of the system. Instead of drilled or laser-cut holes or slits, the slits are formed by stamping discs from the stainless steel plate, such that the discs extend parallel to the surrounding flat area but are raised just sufficiently to define a plurality of slits under each disc, preferably two to four slits, each being an arc of slightly less than 180°, 120° or 90°, respectively. A pair of metal bridges remain to integrally connect the raised disc and the surrounding flat field. Consistent perforation width is achieved, at, for example, 0.010″ width varying by less than 0.001″ in either direction, improving consistency of pressure drop. In addition, the raised discs during backflushing of the underdrain create an outwardly diverging water flow pattern which is beneficial in clearing trapped particles from the filter medium in the vicinity of the underdrain perforations.