Patent ID: 6830107
Filing Date: 2004-12-14
Classification: E21B

Abstract:
A fluid flow switching device for use in an associated drill string comprising a tubular member or pipe adapted to be connected at each end to a respective section of the associated drill string so as to be continuous therewith and having a port in the side thereof, a sleeve member axially slidable within the tubular member between a first upper position in which a port in the side thereof is in alignment with the said port in the side of the tubular member and a second lower position in which the port in the side of the tubular member is obstructed and closed by the sleeve member, a plurality of fingers each of which is pivotably connected at one end to the lower end of the said sleeve and which at the other end defines one segment of a segmented circularly closure member, the segmented closure member being closed when the fingers are pivoted radially inwardly to bring the segments together and being open when the fingers are pivoted radially outwardly to separate the segments, and an annular operating surface positioned within the tubular member beneath the sleeve member, which annular operating surface diverges radially outwardly from the upper end thereof towards the lower end thereof and over which the said plurality of fingers are axially slidable as the sleeve member is moved between the said first upper position in which each of the plurality of fingers is biased radially inwardly causing the segmented closure member to obstruct the tubular member, and the said second lower position in which each of the plurality of fingers is biased radially outwardly causing the segmented closure member to open.