Abstract: Detection of liquid leaks and other changes in variables is disclosed. The event causes two elongate conductors to become electrically connected at a location which is determined by the event, thus creating a system in which the connection point can be located by measuring the potential drop from one end of one of the conductors (called the locating member) to the connection point. The system comprises a balancing component so that its sensitivity is not dependent on the location of the event along an elongate path. A fixed current flows through the connection, so that the result is independent of the resistance of the connection. The locating member can be a continuous resistive wire, coated with a conductive polymer; such a locating member can form part of a sensor cable in which the elongate components of the circuit are in a wrapped configuration. Alternatively the locating member comprises a plurality of discrete resistors.

Abstract: A method of determining leaks and loose couplings in a pipe system which transfers liquid medium, and an apparatus for implementing that method. The pipe system includes a conduit having a beginning, an end, an inner pipe which carries the liquid medium and an outer pipe which surrounds the inner pipe. The conduit has a filler material which fills in an annular space between the inner and outer pipes. The leaks and loose couplings are detected and isolated by measuring only resistances of the filler material between the beginning of the conduit and ground yielding a first resistance value, between the end of the conduit and ground obtaining a second resistance value, and finally between the beginning of the conduit and the end of the conduit obtaining a third resistance value. The defect is then detected and located in the conduit using the first, second and third resistance values.

Abstract: An elongate sensor for detecting and locating presence of a liquid, e.g. water or a hydrocarbon. The sensor includes first and second elongate members which are spaced apart from each other and each of which is a metal conductor covered by a conductive polymer; a third, insulated elongate conductor; and an elongate insulating core. At least one of the elongate members is helically wrapped around the core. Presence of the liquid at any point along the length of the sensor causes the first and second members to be electrically connected at that point, creating a system in which the potential drop down one of the members can be measured and the location of the connection determined.

Abstract: Detection of events, e.g. liquid leaks and other changes in varibles. The event causes two conductors to become electrically connected, and thus creating a system in which the connection point can be located by measuring the potential drop from one end of one of the conductors (called the locating member) to the connection point. Preferably a fixed current flows through the connection, so that the result is independent of the resistance of the connection. The locating member can be a continuous resistive wire, preferably coated with a conductive polymer; such a locating member can form part of a sensor cable in which the elongate components of the circuit are in a wrapped configuration, or part of a cable in which the conductors are separated by a member shaped to prevent capillary action of a liquid from connecting the conductors. Alternatively the locating member comprises a plurality of discrete resistors.

Abstract: In electronic devices, such as data processing systems that operate at high frequencies, the integrity of the interconnect or coupling apparatus transferring signals between component modules is critical to prevent compromise of information being transferred. However, the interconnect or coupling apparatus is subject to both long term and to short term impedance variations. Apparatus is disclosed for testing both the long term impedance changes and the rapid fluctuations that are not observable by current testing procedures. In addition, apparatus is disclosed for providing controllable rapid impedance changes to verify the operation of test apparatus, disclosed herein, for measuring the rapid impedance changes.