WO1997015835A1 - Appareil portable et procede de detection de defauts dans les tuyaux - Google Patents

Appareil portable et procede de detection de defauts dans les tuyaux Download PDF

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Publication number
WO1997015835A1
WO1997015835A1 PCT/US1996/017135 US9617135W WO9715835A1 WO 1997015835 A1 WO1997015835 A1 WO 1997015835A1 US 9617135 W US9617135 W US 9617135W WO 9715835 A1 WO9715835 A1 WO 9715835A1
Authority
WO
WIPO (PCT)
Prior art keywords
pulse
antenna
recited
test
longitudinal axis
Prior art date
Application number
PCT/US1996/017135
Other languages
English (en)
Inventor
Gale D. Burnett
Original Assignee
Burnett Gale D
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Burnett Gale D filed Critical Burnett Gale D
Priority to CA 2236215 priority Critical patent/CA2236215A1/fr
Priority to AU74754/96A priority patent/AU7475496A/en
Publication of WO1997015835A1 publication Critical patent/WO1997015835A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
    • G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
    • G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
    • G01N27/9013—Arrangements for scanning
    • G01N27/902—Arrangements for scanning by moving the sensors

Definitions

  • the present invention relates to a portable apparatus for detecting faults in an elongate member, such as a pipe, and also a method related to the same. More particularly, this relates to a portable testing device which can be manually operated to selectively test different portions of a pipe, such as a pipe carrying petroleum products, chemicals, or other substances.
  • the present invention is to provide an apparatus and method of using the same for effectively examining portions of such pipes to detect faults in the pipe.
  • the present invention provides a method and system for inspecting a member to detect anomalies in the member, where the member has a longitudinal axis, and also has, in an unfaulted condition, substantial uniformity along the longitudinal axis relative to its electromagnetic wave propagation characteristics, except where an anomaly is present.
  • the method comprises first providing a portable test apparatus comprising a portable support structure having an operating axis . There are first and second antennas mounted to the support structure at spaced antenna locations at a predetermined spacing distance along the operating axis .
  • the apparatus is positioned at an operative first test position along the axis, with the first and second antennas being operatively positioned and directed toward respective longitudinally spaced first and second test locations at a predetermined distance along the longitudinal axis .
  • the method further comprises receiving by means of the second antenna the received electromagnetic signal from the electric pulse passing through the second test location and analyzing the received signal by making a comparative analysis of the received signals to the pulse as the pulse existed at said first test location.
  • the apparatus With the apparatus being portable, the apparatus can then be moved to another location along the longitudinal axis of the member under test, and the above method is repeated by using the apparatus at this other location.
  • the analysis comprises examining a leading edge of the pulse. More particularly, the method comprises analyzing slope of the leading edge of the pulse. Also, the analysis comprises analyzing alignment deviations of the leading edge of the pulse. Also, a preferred method of the present invention comprises establishing a base configuration of the signal, corresponding to a signal resulting from the pulse traveling through an uncorroded section of the member to the second antenna. Then subsequent test pulses are compared to the base configuration of the signal. This can desirably be accomplished by transmitting the electric pulse into the member at a location spaced from the first antenna, so that the pulse travels along the longitudinal axis to the first antenna and thence to the second antenna.
  • An alternative is to transmit the pulse through the first antenna to in turn to be transmitted into the member and to travel along the longitudinal axis to the second antenna.
  • the present invention further comprises analyzing the signal by identifying a phase shift of the pulse traveling from the first test location to the second test location.
  • the phase shift is accomplished by analyzing the phase shift at a leading edge portion of the pulse.
  • the pulse has a relatively short rise time. This rise time is less than ten seconds, and in the preferred form less than two seconds, and in a more preferred configuration no greater than about one nanosecond.
  • the apparatus of the present invention has a propagation time which is equal to a time period it takes the pulse to travel through the member from the first test location to the second test location.
  • the pulse is either a relatively long pulse or a relatively short pulse.
  • the pulse width is preferably at least ten times the propagation time between the first and second test locations.
  • the relatively short pulse has a pulse width of one tenth or less of the propagation time between the first and second test locations.
  • the method of the present invention is particularly adapted to operate where the member under test is an elongate pipe, and it is particularly adapted to use where this elongate pipe is an insulated pipe having a main middle structure surrounded by a layer of insulation.
  • Figure 1 is an isometric view illustrating a person using the apparatus of the present invention on an insulated pipe
  • Figure 2 is an elevational view of one of the two antenna components using the apparatus of the present invention
  • Figure 3 is a view similar to Figure 2 showing one of the antenna components engaging the pipe which is being tested;
  • Figure 4 is a schematic view showing the connections between the antenna components and the signal analyzer;
  • Figure 5A is a representation of a wave form that has passed through an uncorroded section of pipe and
  • Figures 5B and 5C are wave forms showing first a clearly corroded section of pipe, and a section where the presence of corrosion is likely;
  • Figure 6 is a schematic drawing of a second embodiment of the apparatus of the present invention.
  • Figure 7 is a view drawn in longitudinal section of another form of an antenna used in the present invention.
  • the fault detecting apparatus of the present invention is shown at 10 where it is being positioned to test a portion of the pipe 12.
  • This fault detecting apparatus 10 (also called a testing device 10) has a first handle section 14 which is adapted to be manually grasped and is connected at a pivot location 16 to another elongate handle portion 18.
  • the distance between the two antenna components 20 and 22 could obviously be made shorter or longer.
  • the rod 24 could be made adjustable in some manner (e.g. by telescope type connections) so that the distance between the antennas 20 and 22 could be conveniently changed.
  • a first cable 26 is connected to one of the antenna components 20, and a second cable 28 is connected to the other antenna component 22.
  • These two cables 26 and 28 are in turn connected to a pulse analyzer or pulse wave analyzer 30 which can be a digital signal analyzer. (See the schematic drawing of Figure 4) .
  • the pulse wave analyzer 30 could be, for example, a Tecktronics Signal Analyzer DSA 601A, or Model TDS 744A.
  • the particular pipe 10 shown herein comprises a steel or iron pipe member 32 surrounded by a layer of insulation 34.
  • Each of the antenna components 20 and 22 comprises a curved plate 36 of sheet metal, with the lower ends 38 of the metal piece 36 being interconnected by a flexible length of rope or chain 40 to locate the sheet metal plate 36.
  • the connecting rod 24 is connected by a screw 42 or other means to each of the antenna components 20 and 22.
  • a pulse generator shown schematically at 44, which is connected electrically to the pipe portion 32.
  • a pulse generator which would be suitable for use in the present invention is one provided by Stanford Research, Model DG 535A.
  • This pulse generator 44 transmits pulses having a pulse width of, for example, possibly as high as one thousand nanoseconds or higher, or much shorter.
  • the pulse width is substantially less than, or substantially greater than, the pulse propagation time between the two antennas 20 and 22, desirable results can be obtained. More specifically, as a guideline, it would be satisfactory to have the pulse be equal to, or greater than, ten times the propagation time between the antennas, or equal to, or less than, one tenth of the propagation time between the two antennas. Thus, if the propagation time between the two antennas would be ten nanoseconds, then in applying these guidelines, the longer pulse width would be one hundred nanoseconds or longer, while the shorter pulse width would be one nanosecond or less. However, depending on application or certain circumstances, it is obvious that pulses could be used which are between those two upper and lower suggested ranges .
  • the pulse generator 44 transmits the pulses into the metal pipe member 32 at regular intervals.
  • the apparatus 10 is then positioned adjacent to the pipe section that is under test, so that the two antenna components 20 and 22 are positioned immediately adjacent to the pipe 12 as indicated in Figure 1.
  • the rise time, amplitude and wave form of the pulse at each antenna component are measured and recorded by the analyzer 30, and also any phase shift in the signal.
  • the apparatus is moved on to other locations on the pipe 12.
  • the slope and wave form of the leading edge of the pulse is particularly significant. Also any phase shift in the signal or pulse traveling from the antenna 30 to the antenna 22 is significant.
  • the wave form would be substantially uniform as it passes under one antenna component 20 and also through the other antenna component 22, and there would be no phase shift.
  • the pulse is imparted into the steel or iron pipe portion 32 and is traveling from left to right, as seen in Figure 1.
  • the pulse arriving at the antenna component 20 would have a leading edge wave configuration which would be the same as (or very close to the same as) wave forms passing through the undamaged sections of the pipe 12 to the left of the antenna component 20.
  • the shape of the pulse will undergo a change, and thus the wave form traveling from that fault section to the antenna component 22 would be modified in its configuration.
  • FIG. 5A shows the wave form where voltage is plotted against time of the leading edge 46 of the pulse, and where the pulse has been traveling along an uncorroded section of pipe.
  • This pulse should have at its leading edge a very rapid rise time, in the order of one nanosecond, or desirably much less than that. In any event, the rise time should certainly be less than rise time of ten nanoseconds five nanoseconds, or two nanoseconds.
  • the strength of the pulse can be varied.
  • the pulse could be, for example, a four volt pulse at twenty milliamps. However, these valves could be changed within limits compatible with the requirements of the present invention and the conditions .under which it is operating.
  • the leading edge of the pulse 46 shown at Figure 5A would be typical of the pulse whose path of travel has been through an uncorroded section of pipe.
  • the wave form shown at 48a in Figure 5B is representative of the leading edge of the pulse after it has passed through a corroded section of pipe and picked up by the antenna component 22. Not only is the slope and configuration of the leading edge of the pulse changed, but there has also been a phase shift, due to the slower velocity of the pulse as it travels from the antenna component 20 through the corroded section of pipe and is then picked up by the second antenna component 22.
  • the wave form at 48b in Figure 5C indicates an area where corrosion is likely.
  • the pulse traveling adjacent to the antenna 20 would be recorded, and then the same pulse would again be recorded as it travels adjacent to the next antenna component 22.
  • the pulse wave forms from the antenna components 20 and 22 are compared, and also any phase shift would be detected. If the configuration of the pulse (particularly the leading edge) remains substantially unchanged, and if there is no phase shift, then that portion of the pipe then under test would be a non-corroded section of the pipe. However, if variations occur (such as shown at 48a of Figure 5B) , this would indicate corrosion.
  • the apparatus 10 is moved to another location of the pipe. Then the method as described above would then be repeated.
  • the entire pipe could be tested by moving the apparatus 10 systematically along the entire length of the pipe, or selected sections could be tested.
  • the manner in which the pulses are transmitted into the pipe could be varied. This is described briefly in conjunction with Figure 6, where a second embodiment is shown. Components which are similar to components described earlier herein will be given like numerical designations with an "a" suffix, distinguishing those of this second embodiment.
  • this second embodiment there are two antenna components 20a and 22a joined by the rod 24a. For convenience of illustration, only the handle component 18 is shown.
  • the pulse generator 44a is connected directly to the antenna component 20a, so that the antenna 20a in turn transmits the pulse into the pipe. Then the pulse travels along the pipe 12a to the second antenna 22a.
  • the configuration and other characteristics of the pulse transmitted into the antenna component 20a are known, if the pipe section between the antenna components 20a and 22a is uncorroded, then the configuration and phase of the pulse at the antenna component 22a will be consistent. However, if there is a corroded section of pipe between the antenna components 20a and 22a, the pulse recorded by the second antenna component 22a will have a modified configura ion, thus indicating corrosion.
  • the pulse analyzer 30a is in the second embodiment connected only to the second antenna component 22a.
  • FIG. 7 A more recent design of the antenna 20 or 22 is shown in Figure 7.
  • This more recent design of the antenna is generally designated 70 and comprises a stem 72 by which it is attached to the rod 24.
  • a wire or other conductor 74 positioned within the stem 72, and this wire 74 connects to a contact probe 76 centrally positioned in a socket 78 defined by a cylindrical wall member 80 connected to the lower end of the stem 72.
  • antenna member 82 having a mounting portion 84 which is threaded into the socket 74 so that the antenna 82 comes into operative connection with the contact probe 76 which extends into a central opening in the mounting portion 84.
  • This particular antenna 82 is an omni-directional probe having a frequency response in the one to two gigahertz range.
  • the antenna member 82 is a Near Field Probe, Model 7405-904B, made by Electro Mechanics of Austin, Texas.
  • this antenna 82 has a frequency response to pulses in the one/half to one nanoseconds range.
  • a shield 86 having a generally hemispherical shape or an outwardly and then downwardly curved sloping shape.
  • the upper edge portion 88 of the shield 86 surrounds, and connects to, the lower end of the stem 72.
  • the main portion 90 of the shield 86 extends outwardly in an increasingly downward curve to a lower circumferential edge 92.
  • This shield is made of aluminum sheet material so as to attenuate any E Field waves to shield the antenna 82 from extraneous waves .
  • the aluminum plate member can be coated on its inside and outside surfaces with paint, such as a spackled paint to provide stiffness and also act as a protective coating.
  • the E Field probe or antenna 82 is designed so as to be responsive to the E Field waves from the pipe, but shields the H Field waves.
  • two such antennas 70 are positioned in the same manner as the antennas 20 and 22, and substantially the same process is used as described above.
  • the antennas 20 and 22 or the antennas 70 substituted for these
  • the apparatus 10 could be provided with visible laser beams, which coincide with the axis of transmission and/or reception of the antenna. In this manner, if the pipe is at a less accessible location (positioned twenty feet or more above the ground surface) , the testing of the pipe could still be accomplished without having to be immediately adjacent to the pipe. It is to be recognized that various modifications could be made to the present invention without departing from the basic teachings thereof.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
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  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)

Abstract

L'invention concerne un procédé d'essai d'un élément allongé tel qu'un tuyau (12) dans lequel circulent des produits pétroliers ou d'autres liquides, et en particulier un tuyau doté d'une couche d'isolation (34). Elle porte aussi sur un appareil d'essai portable (16) comprenant une paire d'antennes (20, 22) montées sur une structure de support portable, en des points espacés. Les antennes sont adjacentes au tuyau et une impulsion (46) présentant un temps de front relativement court est envoyée le long du tuyau de sorte qu'elle passe par les point d'essai au niveau des première et seconde antennes. Lorsqu'une partie du tuyau située entre les antennes est corrodée, on constate une modification de l'impulsion (48a, 48b), que l'on peut analyser pour identifier la zone de corrosion.
PCT/US1996/017135 1995-10-27 1996-10-25 Appareil portable et procede de detection de defauts dans les tuyaux WO1997015835A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CA 2236215 CA2236215A1 (fr) 1995-10-27 1996-10-25 Appareil portable et procede de detection de defauts dans les tuyaux
AU74754/96A AU7475496A (en) 1995-10-27 1996-10-25 Portable pipe defect detecting apparatus and method

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US599395P 1995-10-27 1995-10-27
US60/005,993 1995-10-27

Publications (1)

Publication Number Publication Date
WO1997015835A1 true WO1997015835A1 (fr) 1997-05-01

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PCT/US1996/017135 WO1997015835A1 (fr) 1995-10-27 1996-10-25 Appareil portable et procede de detection de defauts dans les tuyaux

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0885396A1 (fr) * 1996-02-27 1998-12-23 Profile Technologies, Inc. Appareil et procede pour tester des canalisations
WO2011157569A1 (fr) * 2010-06-15 2011-12-22 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Appareil portatif et procédé pour vérifier la présence de corrosion sur un objet métallique sensible à la corrosion

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2696976A1 (fr) * 1992-10-21 1994-04-22 Jacques Lustiere Bâti pour la constitution d'emballages en carton avec des flans dotés de pré-pliures.

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4142143A (en) * 1977-11-18 1979-02-27 The United States Of America As Represented By The Secretary Of The Navy Lightning ground system attachable admittance testing instrument
US4695788A (en) * 1984-12-11 1987-09-22 Hughes Aircraft Company Open fault location system for photovoltaic module strings
WO1989006805A1 (fr) * 1988-01-13 1989-07-27 Prana Recherche Et Developpement Dispositif d'injection d'un signal electromagnetique dans un conducteur electrique
US5530367A (en) * 1995-01-06 1996-06-25 Fluke Corporaton Pulse based cable attenuation measurement system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4142143A (en) * 1977-11-18 1979-02-27 The United States Of America As Represented By The Secretary Of The Navy Lightning ground system attachable admittance testing instrument
US4695788A (en) * 1984-12-11 1987-09-22 Hughes Aircraft Company Open fault location system for photovoltaic module strings
WO1989006805A1 (fr) * 1988-01-13 1989-07-27 Prana Recherche Et Developpement Dispositif d'injection d'un signal electromagnetique dans un conducteur electrique
US5530367A (en) * 1995-01-06 1996-06-25 Fluke Corporaton Pulse based cable attenuation measurement system

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0885396A1 (fr) * 1996-02-27 1998-12-23 Profile Technologies, Inc. Appareil et procede pour tester des canalisations
EP0885396A4 (fr) * 1996-02-27 2007-09-26 Profile Technologies Inc Appareil et procede pour tester des canalisations
WO2011157569A1 (fr) * 2010-06-15 2011-12-22 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Appareil portatif et procédé pour vérifier la présence de corrosion sur un objet métallique sensible à la corrosion

Also Published As

Publication number Publication date
AU7475496A (en) 1997-05-15

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