US Patent 7441441 Automatic leak detection and isolation system for a pipeline

An automatic leak detection and isolation system for a fluid pipeline (3) comprising a pipeline section (1) through which the fluid flows, the pile line section comprising an inner section (5) through which the fluid flows and a sleeve (9) coaxial with and surrounding the inner section (5) and filled with a hydraulic fluid under pressure. A sensing device (not shown in this figure) is provided for sensing a reduction of the pressure of the hydraulic fluid indicating a leakage from or within the pipeline (3), and closure means (11) are provided, actuable in response to the sensing device sensing a reduction in pressure of the hydraulic fluid to close off one end of the pipeline section (1).