US Patent 9133684 Downhole tool

A downhole tool comprising an inner sleeve with a plurality of sleeve ports and a housing positioned radially outwardly of the inner sleeve and having a plurality of housing ports, with the housing and inner sleeve partially defining a space radially therebetween. The space is occupied by a shifting sleeve. A fluid path extends between the interior flowpath of the tool and the space. A fluid control device, occupies at least portion of the fluid path, and may selectively permit fluid flow, and thus pressure communication, into the space to cause a differential pressure across the shifting sleeve. When a sufficient differential pressure is reached, the shifting sleeve is moved from a first position to a second position, which opens the communication paths through the housing and sleeve ports between the interior flowpath and exterior of the tool.