Measuring and testing – With fluid pressure – Leakage
Reexamination Certificate
2001-11-27
2003-03-18
Williams, Hezron (Department: 2856)
Measuring and testing
With fluid pressure
Leakage
C073S040000, C073S170040
Reexamination Certificate
active
06532801
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a simple and reliable portable apparatus and method for tracing a gas leak, particularly a fuel gas leak.
DISCUSSION OF THE BACKGROUND
Gas leak detection is an important safety issue to most oil and gas industries. In the United Kingdom there is a network of over 0.25 million kilometers of pipe. Gas leaks present a hazard across the entire gas chain, from offshore gas and oil exploration and production, through to the processing, transmission, storage and distribution of gas onshore, to its utilisation by industrial and domestic customers. Many thousands of engineers are engaged in the United Kingdom in day-to-day gas detection activities in response to typically half a million public reported escapes per year.
Conventionally Emergency Response teams are only equipped with gas detectors to locate a gas leak. When the plume of gas from a leak is detected, the engineers have to scan the area very slowly and in all directions by trial and error to find the source of the gas leak. However, such a method is time consuming and unreliable as the engineer must walk around randomly trying to find the source of the gas leak. It is an object of the present invention to provide a method and apparatus to quickly and reliably locate the source of a gas leak.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention there is provided an apparatus for identifying the location of a gas leak source, the apparatus comprising
a gas detector for detecting the presence of a gas and
a wind direction indicator.
From the wind direction at the point where gas is detected, one can determine the direction of the source of the leaking gas. This information can be used by an engineer to locate the gas leak source. An engineer can perform more than one measurement at different locations and use the plurality of determined directions to identify the location of the gas leak source more precisely.
The apparatus is preferably portable to enable it to be moved around by an engineer to detect leaking gas. The apparatus may for example be a hand held device or may be provided on a support with one or more wheels such as a trolley.
The gas detector could detect the presence or absence of gas or could measure the concentration of any gas present.
According to a second aspect of the present invention, there is provided a method for identifying the likely location of a gas leak source, the method comprising
detecting the presence of gas using a gas detector;
measuring the wind direction at the point where gas is detected using a wind direction indicator; and
determining the location of a gas leak source using pipeline layout information by determining the intersection of the wind direction at the point where gas was detected and the location of a pipeline from the pipeline layout information.
Pipeline layout information which is often supplied in the form of data to be read and displayed by a computer or as a map is generally readily available to engineers and can easily be used in conjunction with information obtained from a gas detector and a wind direction detector to locate the gas leak source. If a map in the form of electronic data is used, a computing means may be used to determine the location of the gas leak source from the wind direction where gas is detected and the pipeline layout information.
According to a third aspect of the present invention there is provided a method of tracing a gas leak source location comprising
a first step of detecting the presence of gas using a gas detector;
a second step of determining the wind direction at the point where gas is detected using a wind direction indicator;
a third step of moving the gas detector and wind direction indicator upwind in the determined wind direction and continuing to detect the presence of gas until the detected presence of gas starts to disappear;
a fourth step of moving the gas detector in sweeps in the directions transverse to the wind direction whilst continuing to detect for the presence of gas and if substantially no gas is detected in the transverse sweeps, the point where the detected presence of gas started to disappear is substantially the gas leak source location, or if gas is detected in the movements transverse to the wind direction, the third and fourth steps are repeated from substantially the central point where gas is detected in the transverse sweeps until no gas is detected in the latest transverse sweeps.
According to a fourth aspect of the present invention there is provided a method of tracing a gas leak source location comprising
a first step of detecting the presence of gas using a gas concentration detector;
a second step of determining the wind direction at the point where gas is detected using a wind direction indicator;
a third step of moving the gas detector and wind direction indicator upwind in the determined wind direction and continuing to detect the presence of gas until the detected presence of gas starts to disappear and
a fourth step of moving the gas detector in sweeps in the directions transverse to the wind direction whilst continuing to detect for the presence of gas and if no gas is detected in the transverse sweeps, the point where the detected presence of gas started to disappear is substantially the gas leak source location, or if gas is detected in the movements transverse to the wind direction, the third and fourth steps are repeated from the point with substantially the greatest detected concentration during the transverse sweeps until no gas is detected in the latest transverse sweeps.
By following the method according to the third or fourth aspects of the present invention the location of a gas leak can be found quickly and precisely without the need for pipeline layout information.
The invention is not limited to the detection of fuel gas such as natural gas. When other gas detectors are used, the invention can find broad applications in chemical refineries and storage plants and for environmental pollution monitoring purposes.
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Pride Russell Desmond
Shan Qing
Lattice Intellectual Property Ltd
Wiggins David J.
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