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: A method for estimating a location of a leak (x) in a pipe (1). A liquid of a known density is fed into the pipe at a first inlet pressure (P1). When the liquid achieves a substantially steady flow rate, the flow rate passing into the pipeline is recorded. This step is repeated at a second, different, inlet pressure (P2). Using this data, an estimate of the leak location (x) and the area of the leak is calculated by simultaneously solving an expression which is based on relating the frictional energy losses of the liquid travelling through the pipeline (1) to the pressure in the pipeline at the leak (Pleak) and the flow rate of liquid from the leak.

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: The present invention relates to a method of assessing the condition of a duct along which a gas is flowing. The method comprises producing one or more sensor carrying elements, wherein the elements are formed to have selected parameters; introducing the sensor carrying elements into the flowing gas; and selecting the parameters of the sensor carrying elements such that the elements are transported along the duct by saltation. The present invention also relates to a method of reducing leakage through a leak in the duct.

Abstract: A method and system for deriving fluid leak information are described. A plurality of sealing elements are introduced into the pipeline at a location upstream of the leak, and at least some of the sealing elements are drawn towards the leak to cause a sealing event which reduces fluid seepage. A pressure change caused by the sealing event is detected, and associated time data is used to derive information about the leak. In one embodiment, leak location information is derived. In an alternative embodiment, pressure transient information is used to derive leak size information.

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: A method and system for deriving fluid leak information are described. A plurality of sealing elements are introduced into the pipeline at a location upstream of the leak, and at least some of the sealing elements are drawn towards the leak to cause a sealing event which reduces fluid seepage. A pressure change caused by the sealing event is detected, and associated time data is used to derive information about the leak. In one embodiment, leak location information is derived. In an alternative embodiment, pressure transient information is used to derive leak size information.