Abstract: The invention provides an apparatus and methods for duct leakage control wherein a sealing element is introduced into the duct and is automatically drawn or otherwise guided to the locality of a leak, the element being caused, by reason of a pressure differential attributable to the leak, to move into and stem or seal the leak. The sealing element may comprise a plurality of individual members of differing buoyancy, each capable of being carried along at a predetermined level in the duct by the flow of fluid therein. The sealing element may carry a tagging device which can be used to assist in locating the leakage site.

Abstract: The invention relates to the control of leakage from ducts, such as fluid-carrying pipework, without necessarily requiring direct access to the leakage site itself; since leakage sites are often difficult to locate with the necessary degree of precision to permit access to reliably be made thereto, and moreover, even if a site can be located, it is not always convenient or economically possible to secure access thereto. The invention provides an apparatus and methods for duct leakage control wherein a sealing element (1) is introduced into the duct and is automatically drawn or otherwise guided to the locality of a leak; the element being caused, by reason of a pressure differential attributable to the leak, to move into and stem or seal the leak. The sealing element may comprise a plurality of individual members of differing buoyancy, each capable of being carried along at a predetermined level in the duct by the flow of fluid therein.

Abstract: A method is provided for reducing seepage through a leak (5) in a duct (1), the leak being defined in terms of its maximum dimension xL and its maximum width in an orthogonal direction yL and the effective size of the leak being given by formula (1): SL=(x2L+y2L)1/2. A plurality of sealing elements (3) are introduced into the duct, the sealing elements having dimensions a, b and c in mutually orthogonal directions and the effective size SE of the sealing element being given by formula (2): SE=(a2+b2+c2)1/2. The sealing elements have an effective size SE, which is less than the effective size of the leak SL, so that sealing elements (3A) are drawn to the leak locality and caused, by reason of a pressure differential at that locality and attributable to the leak, to move over the leak and reduce the seepage.

Abstract: The invention relates to the control of leakage from ducts, such as fluid-carrying pipework, without necessarily requiring direct access to the leakage site itself; since leakage sites are often difficult to locate with the necessary degree of precision to permit access to reliably be made thereto, and moreover, even if a site can be located, it is not always convenient or economically possible to secure access thereto. The invention provides an apparatus and methods for duct leakage control wherein a sealing element (1) is introduced into the duct and is automatically drawn or otherwise guided to the locality of a leak; the element being caused, by reason of a pressure differential attributable to the leak, to move into and stem or seal the leak. The sealing element may comprise a plurality of individual members of differing buoyancy, each capable of being carried along at a predetermined level in the duct by the flow of fluid therein.