Automated leak detection apparatus and method
First Claim
1. A leak detection method for detecting fluid leakage on a repetitive cycling monitoring basis from at least one of a plurality of fluid storage vessels, including subsurface fluid storage tanks, aboveground fluid storage tanks and fluid pipelines disposed in or on an earthen material, comprising the steps of:
- (a) doping the fluid contained with the at least one of a plurality of fluid storage vessels with a chemical tracer, the tracer having a gas chromatography signature separate and distinct from the fluid and from earthen material supporting the at least one of a plurality of fluid storage vessels and capable of molecular diffusion within the earthen material in the gas phase;
(b) disposing a plurality of sampling means for collecting soil gas samples, the plurality of sampling means forming an array in the earthen material in fluid flow proximity to the at least one of a plurality of fluid storage vessels, each of the plurality of sampling means having a gas conduit coupled thereto;
(c) selecting a first of the plurality of sampling means;
(d) evacuating a first soil gas sample from the first of the plurality of sampling means by applying a negative pressure to the first of the plurality of sampling means;
(e) loading the evacuated first soil gas sample into a sample loop by applying the negative pressure through the sample loop thereby moving the first soil gas sample from the first of the plurality of sampling means into the sample loop;
(f) connecting the sample loop to a gas chromatograph;
(g) flowing a carrier gas into and through the sample loop, thereby displacing the evacuated first soil gas sample out of the sample loop and into the gas chromatograph;
(h) analyzing the first soil gas sample in the gas chromatograph and outputting at least one data signal characterizing the soil gas sample from the gas chromatograph;
(i) processing the at least one data signal characterizing the soil gas sample from the gas chromatograph and interpolating the at least one data signal from the gas chromatograph and outputting an integrated data signal containing identification data from the gas sample from the gas chromatograph to determine the presence of tracer in the soil gas sample;
(j) activating a signal indicative of the detection of the tracer in the soil gas sample; and
(k) repeating steps d) through j) until each of the plurality of sampling means in the array have been tested.
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Accused Products
Abstract
A system for automated soil gas sampling, analysis and reporting to determine the presence and magnitude of a fluid leak from fluid storage vessels by detecting the presence of a unique and identifiable tracer chemical in the fluid leak. The system includes an array of sampling probes disposed in earthen material supporting fluid storage vessels. Each of the sampling probes is connected to a first valve selectable between individual sampling probes in the array. The first valve is connected to a second valve which communicates a gas sample from the first valve to a sample loop and loads the gas sample into the sample loop. Switching of the second valve from the first valve to a carrier gas source introduces a pressurized carrier gas into the sample loop displacing the gas sample out of the sample loop and into a gas chromatograph for analysis. A process controller governs all switching functions of the valves, actuation of the vacuum pump and the gas chromatograph in accordance with a pre-programmed instruction set. Data output by the gas chromatograph is processed to determine the presence of a tracer in the soil gas sample and actuate a signal flag indicative of the presence of the tracer chemical in the soil gas sample.
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Citations
27 Claims
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1. A leak detection method for detecting fluid leakage on a repetitive cycling monitoring basis from at least one of a plurality of fluid storage vessels, including subsurface fluid storage tanks, aboveground fluid storage tanks and fluid pipelines disposed in or on an earthen material, comprising the steps of:
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(a) doping the fluid contained with the at least one of a plurality of fluid storage vessels with a chemical tracer, the tracer having a gas chromatography signature separate and distinct from the fluid and from earthen material supporting the at least one of a plurality of fluid storage vessels and capable of molecular diffusion within the earthen material in the gas phase; (b) disposing a plurality of sampling means for collecting soil gas samples, the plurality of sampling means forming an array in the earthen material in fluid flow proximity to the at least one of a plurality of fluid storage vessels, each of the plurality of sampling means having a gas conduit coupled thereto; (c) selecting a first of the plurality of sampling means; (d) evacuating a first soil gas sample from the first of the plurality of sampling means by applying a negative pressure to the first of the plurality of sampling means; (e) loading the evacuated first soil gas sample into a sample loop by applying the negative pressure through the sample loop thereby moving the first soil gas sample from the first of the plurality of sampling means into the sample loop; (f) connecting the sample loop to a gas chromatograph; (g) flowing a carrier gas into and through the sample loop, thereby displacing the evacuated first soil gas sample out of the sample loop and into the gas chromatograph; (h) analyzing the first soil gas sample in the gas chromatograph and outputting at least one data signal characterizing the soil gas sample from the gas chromatograph; (i) processing the at least one data signal characterizing the soil gas sample from the gas chromatograph and interpolating the at least one data signal from the gas chromatograph and outputting an integrated data signal containing identification data from the gas sample from the gas chromatograph to determine the presence of tracer in the soil gas sample; (j) activating a signal indicative of the detection of the tracer in the soil gas sample; and (k) repeating steps d) through j) until each of the plurality of sampling means in the array have been tested. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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2. A system for detecting fluid leakage from at least one of a plurality of fluid storage vessels containing fluid with chemical tracer doped within, including subsurface fluid storage tanks, aboveground fluid storage tanks and fluid pipelines supported by an earthen material, comprising:
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(a) a plurality of gas permeable sample probes that are tubular member disposed to form an array in the earthen material in fluid flow proximity to the at least one of a plurality of fluid storage vessels; (b) a plurality of fluid conduit members having first and second ends thereof, the first end of each of the plurality of fluid conduit members being connected in fluid flow communication with a corresponding one of the plurality of gas permeable sample probes; (c) first valve means connected to each of the plurality of fluid conduit members, the first valve means being selectably switchable between each of the plurality of fluid conduit members; (d) second valve means in fluid flow communication with the first valve means; (e) third valve means in fluid flow communication with said first valve means and second valve means and switchable therebetween to draw a vacuum through one of a sample loop bypass line and through said sample loop; (f) a carrier gas source containing a carrier gas under positive pressure, the carrier gas source being connected in fluid flow communication with the second valve means; (g) a sample loop connected in fluid flow communication with the second valve means; (h) pumping means for providing a negative pressure in each of the plurality of sampling probes, the gas conduits, the first valve means and the second valve means and the sample loop, thereby evacuating soil gas samples therethrough; (i) gas analysis means coupled to the second valve means; and (j) control processing means for controlling switching of each of the first, second and third valve means in response to a pre-programmed instruction set governing sequencing of evacuation of each of the sampling probes, loading of the sample loop with evacuated soil gas samples and injection of the evacuated soil gas samples from the sample loop into the gas analysis means. - View Dependent Claims (17, 18, 20, 21, 22, 23, 24, 25, 26, 27)
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19. A system for detecting fluid leakage from at least one of a plurality of fluid storage vessels containing fluid with chemical tracer doped within including subsurface fluid storage tanks, aboveground fluid storage tanks and fluid pipelines supported by an earthen material, comprising:
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(a) a plurality of gas permeable sample probes disposed to form an array in the earthen material in fluid flow proximity to the at least one of a plurality of fluid storage vessels; (b) a plurality of fluid conduit members having first and second ends thereof, the first end of each of the plurality of fluid conduit members being connected in fluid flow communication with a corresponding one of the plurality of gas permeable sample probes; (c) first valve means connected to each of the plurality of fluid conduit members, the first valve means being selectably switchable between each of the plurality of fluid conduit members; (d) second valve means in fluid flow communication with the first valve means; (e) third valve means in fluid flow communication with said first valve means and second valve means and switchable therebetween; (f) a carrier gas source containing a carrier gas under positive pressure, the carrier gas source being connected in fluid flow communication with the second valve means; (g) a sample loop connected in fluid flow communication with the second valve means; (h) pumping means for providing a negative pressure in each of the plurality of sampling probes, the gas conduits, the first valve means and the second valve means and the sample loop, thereby evacuating soil gas samples therethrough; (i) gas analysis means coupled to the second valve means; and (j) control processing means for controlling switching of each of the first, second and third valve means in response to a pre-programmed instruction set governing sequencing of evacuation of each of the sampling probes, loading of the sample loop with evacuated soil gas samples and injection of the evacuated soil gas samples from the sample loop into the gas analysis means; wherein said second valve means is at least a two way valve, switchable between a connection between said pumping means and said plurality of sample probes and a connection between said carrier gas source and said gas analysis means.
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Specification