US Patent 9518439 Annular barrier with a self-actuated device

An annular barrier to be expanded in an annulus between a well tubular structure and an inside wall of a borehole downhole, includes a tubular part for mounting as part of the well tubular structure. The tubular part has a longitudinal axis, an expandable sleeve surrounding the tubular part and having an outer face, each end of the expandable sleeve being fastened to the tubular part by a connection part, an annual barrier space between the tubular part and the expandable sleeve, an aperture in the tubular part or the connection part for letting fluid into the space in order to expand the sleeve, and a self-actuated device arranged in the aperture having an open and a closed position.