Drilling tool incorporating suction jet - creates pressure difference accelerating flow of debris-laden mud, keeping tool clean, increasing drilling speed and reducing wear

摘要

The tool comprises a body rotated by a tool carrier and contg. a cavity to receive a fluid under pressure through the tool carrier. The body carriers a number of rotating components provided with elements for attacking the ground on a working front, a means of irrigation able to deliver fluid jets directed towards the working front and a means of aspirating the fluid after it has irrigated components, able to deliver an ascending suction jet. The means of irrigation comprise first calibrated orifices in the body of the tool communicating with the cavity and opening into spaces between two adjacent rotating components. The means of suction comprises second calibrated orifices situated above a second space between tow adjacent rotating components. The first calibrated orifices are oriented parallel to the axis of the tool and open at a distance from the working front between 1/3 H and 4/5 H, H being the height of the attacking elements measured parallel to the axis of the tool. The appts. is an improvement as that described in the parent patent. The pressure difference produced between the working front and the zone where the suction jet is situated accelerates considerably the upward flow of mud charged with debris.