Apparatus for the generation of pressure pulses in drilling mud compositions

Abstract

The apparatus for the generation of pressure pulses in a drilling mud composition which flows downward in a drill string (1) is composed of a valve (V) inside the drill string (1), with a stationary, braced, tubular exterior housing (3), tubular primary valve (4) which can be translated from a lower starting position against the flow direction (2) of the drilling mud composition into an upper operational end position, a stationary, tubular support (5) in a coaxial position inside primary valve (4), and a pilot valve (13), (14) actuated by motor means (15). Exterior housing (3) and primary valve (4) define a constricted segment (29) whose flow cross section can be modified by the position of primary valve (4), and primary valve (4) and the support (5) surround an interior flow channel (21), (12) and (10), which can be opened and closed by outlet orifice (13) of pilot valve (13), (14). The sum of the downward fluid forces and the gravitational forces in the drilling mud composition acting on the primary valve in its starting position when pilot valve (13), (14) is open exceeds the upward fluid forces, and these force relations can be reversed by closing auxiliary valve (13), (14). In the fluid operational end position of primary valve (4), the sum of all forces acting on primary valve (4) is equal to zero, and primary valve (4) is suspended in the drilling mud composition without contacting stop (34) thereabove.

Dependencies are inferred from the claim text.