A simple acoustic detection system is described for measuring leaks from long gas pipelines. Microphones are strung along (and attached to) the pipeline exterior. The outputs of the microphones are spectrally analyzed. A peak at a frequency f≅V s /(2d) and its harmonics indicates a leak in the vicinity of the recording microphone, where V s is the velocity of sound in the gas and d is the thickness of the pipe wall.

Leak detector for natural gas pipelines

A method for locating gas leaks from underground gas pipelines in which a first acoustic sensor having a first signal output is positioned in ground disposed substantially above or at a distance from the underground gas pipeline. At least one second acoustic sensor having a second signal output is positioned in the ground at a plurality of locations substantially above the underground gas pipeline. The output signals from the acoustic sensors are measured for each location of the second acoustic sensor and the signals are adaptively filtered to remove common noise signal components. The statistical minima of these rms voltages are determined for both the first output signal and the adaptively filtered second output signals and the differences determined. The location of the second acoustic sensor corresponding to the largest positive said difference is the location closest to the leak site.

Enhanced acoustic detection of gas leaks in underground gas pipelines

In an abnormality monitoring apparatus of the present invention, a plurality of detectors (13, 14) are arranged at a plurality of positions in the axial direction of a pipeline (11) to detect respective sound waves (37) propagating from a position (B) of occurrence of abnormality. The aforementioned position is calculated from a sound wave detection time difference between the detectors (13, 14) and position between the detectors (13, 14). The apparatus further includes an abnormal waveform memory unit (28) for storing the waveforms of a plurality of kinds of typical abnormal sound waves generated from abnormality on the pipeline (11). A display device (19) displays, on the same image screen, the abnormal waveform stored in the abnormal waveform memory unit and that of the sound wave detected. It is, therefore, possible for a monitoring personnel to readily identify a kind of abnormality occurred.

Abnormality monitoring apparatus for a pipeline

Apparatus for deploying equipment in a fluid container or fluid conduit comprises a fluid housing having an outlet aperture, the fluid housing being adapted to be secured to the container or conduit such that the outlet aperture is in fluid communication with an aperture in the container or conduit. The apparatus further includes a piston in the fluid housing dividing the fluid housing into first and second fluid chambers, the second fluid chamber being in fluid communication with the interior of the container or conduit via the outlet aperture when the fluid housing is secured in fluid communication with the container or conduit. The piston is movable within the fluid housing toward the outlet aperture in response to increases of fluid pressure in the first fluid chamber. The apparatus further includes a guide means for guiding deployment of the equipment into the container or conduit. The guide means is secured to the piston, whereby movement of the piston within the fluid housing can move the guide means at least partially into the container or conduit through said outlet aperture.

Deployment of equipment into fluid containers and conduits

The present invention provides methods of assessing damage on a joint that includes energizing the joint, detecting the vibration of the joint using one or more signal generating sensors, processing the signal(s), and applying a damage index to the processed signal(s), wherein the damage index incorporates a processed control signal generated by a sensor(s) at or near the joint when the joint was healthy, i.e., in a substantially undamaged state. Another aspect of the present invention provides a pipeline that includes at least two pipe segments, at least one joint connecting the two pipe segments, and at least one signal generating sensor affixed to the pipeline that is capable of detecting vibration at or near the joint, at least one signal processor that is capable of EMD processing the signal, and an output device (e.g., computer monitor, LED display, a light bulb, an electronic alarm, or other sound or light generating device).

Vibration based damage detection system

Apparatus and method are provided for the location of pipeline damage and medium leak therefrom by acoustical monitoring of the soil about a pipe and recording emission noise by microphone and an amplifier which controls a peak noise indicator. Each measurement point detected by the amplifier is applied to a digital memory to display a histogram showing noise distribution along the pipe. The main frequency of the loudest measurement point is determined, and an octave filter is utilized to determine the frequency characterizing medium leakage to precisely locate the pipeline damage. Bar diagrams may be provided on a viewplate by bands of parallel arrays of light emitting diodes to display noise distribution along the pipeline. A frequency analyzer may transmit from the amplifier to the memory the peak frequency value of each observed frequency band to enable frequency analysis of the loudest measurement point. The apparatus may have a case with a lid defining openings sized for viewing the bar diagrams.

Method and apparatus for locating pipeline damage

Verfahren zur ortung von rohrschaeden und geraet zur durchfuehrung des verfahrens

L'INVENTION A POUR OBJET UN PROCEDE ET UN APPAREIL POUR LOCALISER LES DEFAUTS ET NOTAMMENT LES FUITES DES TUYAUX EN AUSCULTANT LA REGION DU SOL 15 ENVIRONNANT LE TUYAU DEFECTUEUX 10 ET EN CAPTANT LE BRUIT 14 EMIS PAR LE DEFAUT 12 AU MOYEN DE MICROPHONES 11 QUI SONT RELIES A L'ENTREE D'UN AMPLIFICATEUR 17 QUI COMMANDE UN DISPOSITIF D'AFFICHAGE 20 A 27 INDIQUANT LE MAXIMUM DE CES BRUITS. L'INVENTION COMPREND UNE PREMIERE ETAPE OPERATOIRE DANS LAQUELLE L'AMPLIFICATEUR 17 ENVOIE LE MAXIMUM DU BRUIT DE CHAQUE POINT DE MESURE DANS UNE MEMOIRE DIGITALE 18 QUI PROVOQUE L'AFFICHAGE D'UN HISTOGRAMME 28 DE LA DISTRIBUTION DES BRUITS LE LONG DU TRAJET DE MESURE ET EN CE QUE, DANS UNE SECONDE ETAPE, LES BANDES DE FREQUENCES PRINCIPALES ET PREFERENTIELLES DU POINT DE MESURE LE PLUS INTENSE SONT DETERMINEES ET AUX FINS D'AFFINAGE DE LA LOCALISATION CETTE BANDE DE FREQUENCES EST TRAITEE A L'AIDE D'UN FILTRE D'OCTAVE AFIN DE DETERMINER LA FREQUENCE CARACTERISTIQUE PRODUITE PAR LA FUITE DU FLUIDE.

Eugen Ing Grad Jaeckle

Papers

Method and apparatus for locating pipeline damage

Verfahren zur ortung von rohrschaeden und geraet zur durchfuehrung des verfahrens

Procede pour localiser les defauts, notamment les points de fuites des tuyaux et appareil pour la mise en oeuvre de ce procede