Patent ID: 8922387

Claim:
An electromagnetic (EM) isolation gap sub telemetry apparatus for use in well drilling and production in conjunction with a drilling rig including a derrick, the apparatus comprising: a first electrically conductive cylindrical member including a tapered, male-threaded portion with thread roots and crests; a second electrically conductive cylindrical member including a tapered, female-threaded portion with thread roots and crests adapted for receiving the male-threaded portion of said first electrically conductive cylindrical member; a plurality of non-conductive inserts adapted for preventing direct physical contact between said male-threaded portion and female-threaded portion when the first electrically conductive cylindrical member is threaded with said second electrically conductive cylindrical member, thereby forming an annular gap between said first and second electrically conductive cylindrical members; each said non-conductive insert including an axial runner and multiple thread form extensions extending laterally from said axial runner; each said thread form extension including a pair of downwardly-converging walls forming an upwardly-open, V-shaped configured for placement within a respective thread root; a plurality of axial cuts disposed at intervals around the diameter of the tapered section of either the male-threaded portion, or the female-threaded portion, or both, thereby forming axial slots; wherein said plurality of non-conductive insert runners are placed within said axial slots with their respective extensions placed within respective thread roots on both sides of said axial slot; and said annular gap between said first and second electrically conductive cylindrical members configured for optimal non-contacting alignment between said members prior to permanent attachment being made by injecting epoxy in said annular gap.