Patent ID: 7810573

Claim:
A method for modifying an existing subassembly for a downhole drill string to provide a fluid flow bypass channel, said subassembly having a hollow body member having an outer housing wall and a central passage extending longitudinally from an upper end to a lower end and having a plurality of blades extending outwardly from said hollow body member comprising the steps of: first, providing a plurality of generally parallel channels along an outer surface of said outer housing wall, each of said channels extending longitudinally between rows of said blades, each of said channels extending from below a lower set of said blades to above an upper set of said blades; second, covering each of said channels with a cover sheet member, each of said cover sheets being shorter in length than each of said channels; providing a fluid inlet in said outer housing wall in a lower section of said body below said blades; and providing a fluid outlet in said outer housing wall in an upper section of said body above said blades wherein each of said fluid flow bypass channels are provided in said outer wall between said blades and extending from said fluid inlet to said fluid outlet.