Automated search apparatus for locating leaks in geomembrane liners

Claim 1

An automated search apparatus for locating a leak in a geomembrane liner having a high electrical resistivity, said liner having one face in contact with a conductive liquid contained by said liner and having the opposite face in contact with a conducting material, comprising: means for producing a voltage drop between said contained liquid and said conducting material, thereby creating a voltage gradient on the surface and in the interior volume of said liquid, said voltage gradient having a distribution correlatable with a leak in said geomembrane liner; a propelled, steerable vehicle; voltage gradient sensing means carried on said vehicle, said sensing means operable to detect a voltage gradient on the surface of said liquid, said voltage gradient sensing means comprising first and second electrode pairs, said first electrode pair being aligned along a longitudinal axis of said vehicle, said second electrode pair being aligned along an axis transverse to said longitudinal axis, said first and said second electrode pairs each being connected to first and second differential amplifiers, respectively, whereby first and second output signals are generated which correlate to the voltage potential difference between said first and said second electrode pairs, respectively; means for monitoring the position of said vehicle with respect to a reference point and for generating a position reference signal correlatable with the location of said vehicle with respect to said reference point; and signal processing means responsive to said output signals and said position reference signal and operable to correlate said output signal and said position reference signal with the location of a leak in said liner.

Claim 15

A method of surveying a liquid impoundment to detect the location of a leak in a geomembrane liner containing a conducting liquid within said impoundment, said geomembrane liner having one face in contact with said conducting liquid and having another face in contact with a conduct material, comprising the steps of: creating a voltage drop between said conducting liquid and said conducting material, thereby creating a voltage gradient in said liquid, said voltage gradient having a distribution correlatable with the location of a leak in said liner; placing a propelled steerable vehicle in said liquid, said vehicle having a voltage sensing means carried thereon, said sensing means operable to detect a voltage gradient on the surface of said liquid and to generate an output signal in response thereto; said voltge sensing means having a plurality of pairs of first and second electrodes, each of said pairs being connected to a plurality of differential amplifiers, whereby a plurality of output signals are produced by each of said differential amplifiers, said output signals being correlatable with a voltage potential difference of said first and second electrodes of each of said electrode pairs; moving said vehicle to a plurality of points in said liquid; monitoring the position of said vehicle with respect to a reference point generating a position reference signal correlatable with the location of said vehicle at each of said points in said liquid with respect to said reference point; generating a position reference signal correlatable with the location of said vehicle at each of said points in said liquid with respect to said reference point; transmitting said output signals for each of said points to a monitoring means located on the shore of said impoundment; processing said output signals and said position reference signal corresponding to each said point to obtain a representation of the voltage gradient distribution in said liquid; and correlating said gradient distribution with the location of a leak in said liner.

Claim 16

A method of surveying a liquid impoundment to detect the location of a leak in a geomembrane liner containing a conducting liquid within said impoundment, said geomembrane liner having one face in contact with said conducting liquid and having another face in contact with a conduct material, comprising the steps of: creating a voltage drop between said conducting liquid and said conducting material, thereby creating a voltage gradient in said liquid, said voltage gradient having a distribution correlatable with the location of a leak in said liner; placing a propelled steerable vehicle in said liquid, said vehicle having a voltage sensing means carried thereon, said sensing means operable to detect a voltage gradient on the surface of said liquid and to generate an output signal in response thereto; said voltge sensing means having a plurality of pairs of first and second electrodes, each of said pairs being connected to a plurality of differential amplifiers, whereby a plurality of output signals are produced by each of said differential amplifiers, said output signals being correlatable with a voltage potential difference of said first and second electrodes of each of said electrode pairs; moving said vehicle to a plurality of points in said liquid; monitoring the position of said vehicle with respect to a reference point generating a position reference signal correlatable with the location of said vehicle at each of said points in said liquid with respect to said reference point; generating a position reference signal correlatable with the location of said vehicle at each of said points in said liquid with respect to said reference point; transmitting said output signals for each of said points to a monitoring means located on the shore of said impoundment; processing said output signals and said position reference signal corresponding to each said point to obtain a representation of the voltage gradient distribution in said liquid; and correlating said gradient distribution with the location of a leak in said liner.