WO1990004779A1 - Detection de la corrosion du metal - Google Patents
Detection de la corrosion du metal Download PDFInfo
- Publication number
- WO1990004779A1 WO1990004779A1 PCT/GB1988/000876 GB8800876W WO9004779A1 WO 1990004779 A1 WO1990004779 A1 WO 1990004779A1 GB 8800876 W GB8800876 W GB 8800876W WO 9004779 A1 WO9004779 A1 WO 9004779A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- sensors
- array
- wall
- tie
- voltages
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
-
- 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
Definitions
- This invention relates to apparatus for and a non- intrusive method of detecting metal corrosion, more especially corrosion which occurs in cavity wall ties.
- Cavity walls comprise two skins held in fixed relationship by metal ties, either of wire, mild steel strip or cast iron. Such ties commonly corrode with passage of time, eventually to give rise to cracking of the masonry and possible collapse of the wall. It is clearly desirable to replace corroded wall ties before damage can result, but currently the only reliable method of inspecting ties for corrosion is a destructive one, which entails the removal of bricks or other wall blocks to expose the ties to view.
- apparatus for corrision detection especially detection of corroded wall ties, comprising: i an array of Hall effect sensors;
- SUBSTITUTE SHEET processing circuitry responsive to the voltages generated at the sensors in the array
- the principle of the invention is that the patterns of voltages generated within the array of sensors differ between the situation where the field of the permanent magnet is substantially undisturbed, the situation where it is disturbed by the presence in its vicinity of a sound wall tie, and the situation where it is disturbed to a lesser extent by the presence in its vicinity of a corroded tie, due to the reduce ferrous content of the corroded ties.
- a further aspect of the invention therefore concerns a preferred method of detecting metal corrosion.
- a method of detecting metal corrosion comprises the steps of:
- the individual sensor values taken during determination of the reference signal and determination of the measurement signal are stored, the difference values are determined for each sensor, and the difference values are summed.
- the difference values are determined for each sensor, and the difference values are summed.
- only the voltages of sensors in the central region of the array may be utilised in this method.
- the individual sensor voltages are stored for a tie-absent wall position, thereby to establish a background reference pattern, the individual sensor voltages are stored for one or more sound wall tie positions, thereby to establish a mean sound tie reference pattern, the sensor voltage differences for at least some of the sensors are determined to establish a sound tie difference signal pattern, the individual sensor voltages are stored for a suspect wall tie position, thereby to establish a measurement voltage pattern, the sensor voltage differences (for at least some of the sensors) are determined relative to the background reference pattern in order to establish a suspect tie difference signal pattern, and the sound tie difference signal pattern is
- a background reference pattern is indicated by a minimum sum of the sensor voltages and a sound tie by a maximum value thereof. Centering on a wall tie is indicated by maximum sensor voltages in the central region of the array.
- a typical sensor array would be a two-dimensional array, having a plurality of sensors extending in two mutually perpendicular directions.
- the sum of the difference signal voltages from the sound tie may be compared with the sum of the different signal voltages for a suspect tie.
- a substantial difference in the two sums is indicative of a severely corroded tie.
- it is badly corroded wall ties which are most important to detect, as distinct from ties suffering from only limited corrosion, and it is an advantage of this invention that the apparatus and method is most sensitive when there is in excess of 50% corrosion.
- Summation values obtained for corroded wall ties will vary to some extend with position (orientation and depth) of the tie within the wall, but badly corroded ties will always be detectable.
- an analysis of the pattern of sensor voltages through the array can enable information as to the positioning of the corroded tie to be derived, thus assisting in the work necessary to effect a replacement.
- the magnet and sensor array may constitute a portable unit, and the processing, measuring and display circuitry may be incorporated in a second unit
- a power supply preferably of a rechargable kind, is required for the array of Hall effect sensors, and this may also form part of the second unit.
- At least part of the display equipment may be incorporated in the first unit to facilitate the task of positioning the magnet and array at different sites on the wall.
- One suitable form of basic display is an LCD meter coupled to the sensors via two rotary switches which in combination select a particular sensor for reading on the meter.
- Figure 1 is a block circuit diagram of the apparatus
- Figures 2 to 4 are tables exemplifying results achieved with the exemplary apparatus.
- the reference 10 denotes a 9 x 7 array of Hall effect sensors, conveniently sprague UGN 3503U linear Hall effect sensors.
- This array 10 forms part of a sensor head 12 which also includes a ferrite permanent magnet.
- Figure la shows the circuit element associated with one sensor.
- the remaining parts of the apparatus are incorporated in a supervisory unit 14 connected to the sensor head 12 by 40- way connectors 16, 40-way cables 18 and 40-way plugs/sockets 20.
- a controlled power supply ( Figure lb) includes a sealed lead acid battery 22, a battery indicator 24, recharging leads 26, and a d.c/d.c convertor 28.
- the power supply provides outputs of 0 volts and 5 volts to the sensor head 10.
- the remainder of the supervisory unit comprises circuitry for processing, measuring and displaying the voltages, , developed at the Hall effect sensors in use.
- This circuitry includes four stores 32 to 36, two rotary switches 38, 40, the latter forming part of a drive circuit, generally referenced 42, and which includes an arithmetic unit 44, for a digital display module 46.
- Figures 2 to 4 comprising tables 1, 2 and 3, respectively show the pattern of different signal sensor outputs obtained for a wire tie, a sound cast iron tie, and a corroded cast iron tie.
- the different signals are obtained by substracting the sensor voltages developed in the presence of a tie from the voltages developed in the absence of a tie, ie, when the field of the permanent magnet is substantially undisturbed.
- the voltage pattern in the last mentioned case is substantially uniform over the entire array.
- SUBSTITUTE SHEET can be seen that the highest values are again generally in the centre of the array, the values of the different signals are much reduced, because the disturbance of the magnetic field is substantially less.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Pathology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Immunology (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Biodiversity & Conservation Biology (AREA)
- Ecology (AREA)
- Environmental & Geological Engineering (AREA)
- Environmental Sciences (AREA)
- Investigating Or Analyzing Materials By The Use Of Magnetic Means (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
Abstract
L'appareil décrit sert à détecter du métal corrodé, et en particulier des ancres murales corrodées. On prévoit un réseau de détecteurs à effet de Hall (10), reliés par le champ magnétique d'un aimant permanent, et les sorties provenant des détecteurs sont multipliées par des dispositifs (30, 32, 34, 36, 44) et amplifiées par un amplificateur (42) permettant la mise sous tension d'un module d'alimentation (46) d'un compteur. Les modèles des tensions générées à l'intérieur du réseau des capteurs diffèrent selon les situations, qui sont au nombre de trois: (1) situation où le champ de l'aimant permanent est en substance non perturbé, (2) situation où le champ est perturbé par la présence d'une ancre murale en bon état et (3) situation où le champ est perturbé dans une moindre mesure par la présence d'une ancre corrodée, cette perturbation étant due à la teneur ferreuse réduite de l'ancre corrodée. Dans un procédé de détection d'ancres murales corrodées, une unité contenant le réseau de détecteurs à effet de Hall et l'aimant permanent est placée adjacente à un mur, dans une position où l'aimant est plus éloigné du mur que les détecteurs, et l'unité est déplacée dans une position par rapport au mur où les détecteurs présentent un certain modèle de tension, puis un signal de référence est produit par traitement de la tension des détecteurs. L'unité est ensuite déplacée dans une position où les détecteurs présentent un modèle de tension différent et les tensions des détecteurs sont à nouveau traitées de façon à produire un signal de mesure, le signal de référence et le signal de mesure étant ensuite comparés.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8709033A GB2203549B (en) | 1987-04-15 | 1987-04-15 | Metal corrosion detection |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1990004779A1 true WO1990004779A1 (fr) | 1990-05-03 |
Family
ID=10615875
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1988/000876 WO1990004779A1 (fr) | 1987-04-15 | 1988-10-18 | Detection de la corrosion du metal |
Country Status (2)
Country | Link |
---|---|
GB (1) | GB2203549B (fr) |
WO (1) | WO1990004779A1 (fr) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2001069204A2 (fr) * | 2000-03-14 | 2001-09-20 | British Nuclear Fuels Plc | Ameliorations apportees ou relatives a l'analyse de courant |
US6861853B2 (en) | 2000-03-14 | 2005-03-01 | British Nuclear Fuels Plc | Investigating corrosion |
US6982563B2 (en) | 2000-11-09 | 2006-01-03 | British Nuclear Fuels Plc | Monitoring of corrosion induced loss of material by means of a plurality of electrical resistance measurements (field signature method, electrical resistance tomography) |
CN101788521A (zh) * | 2010-03-19 | 2010-07-28 | 南京工业大学 | 金属腐蚀状况在线检测方法及其检测仪器 |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2054797A1 (fr) * | 1990-11-07 | 1992-05-08 | Nicolaas T. Van Der Walt | Controle electromagnetique de cables metalliques |
DE19654868A1 (de) * | 1996-12-24 | 1998-06-25 | Forschungsgesellschaft Fuer In | Prüfverfahren zur Erkennung von Korrosion |
WO2010117363A1 (fr) | 2009-04-09 | 2010-10-14 | Michelin Recherche Et Technique, S.A. | Procédé et appareil de détection d'anomalies dans un câble métallique de pneu |
CN105067507B (zh) * | 2015-08-24 | 2018-04-06 | 北京星网锐捷网络技术有限公司 | 一种腐蚀检测装置及方法 |
CN108845018B (zh) * | 2016-05-10 | 2020-01-10 | 青岛理工大学 | 一种原电池腐蚀检测装置 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4087749A (en) * | 1977-01-25 | 1978-05-02 | The United States Of America As Represented By The Secretary Of The Army | Method and apparatus for normalizing the outputs of sequentially scanned magnetic flaw detectors |
US4481809A (en) * | 1983-08-29 | 1984-11-13 | Labate M D | Method and apparatus for monitoring erosion in gas stirring devices in molten metal ladles |
US4531091A (en) * | 1982-03-29 | 1985-07-23 | The United States Of America As Represented By The Secretary Of Transportation | Magnetic inspection of reinforcing steel using sensor array |
DE3418066A1 (de) * | 1984-05-16 | 1985-11-21 | Fa. Hermann Nadermann, 4100 Duisburg | Korrosions-testgeraet fuer magnetisierbares stahlblech |
GB2169084A (en) * | 1984-12-21 | 1986-07-02 | Nukem Gmbh | A device for the non-destructive testing of ferromagnetic bodies and a process for producing values for adjusting the device into an initial statee for testing determined by the respective test samples |
EP0238209A2 (fr) * | 1986-03-17 | 1987-09-23 | United Kingdom Atomic Energy Authority | Détection de discontinuités magnétiques |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1038037A (fr) * | 1976-05-06 | 1978-09-05 | Noranda Mines Limited | Dispositif d'essai magnetique pour detecter des defauts dans des objets de forme allongee |
GB2012966A (en) * | 1977-10-06 | 1979-08-01 | Health & Safety Executive | Apparatus for non-destructive testing of elongate objects |
GB2108672A (en) * | 1981-10-17 | 1983-05-18 | Armstrong Patents Co Ltd | Vehicle body repair detector |
US4573013A (en) * | 1982-03-29 | 1986-02-25 | The United States Of America As Represented By The Secretary Of Transportation | Magnetic inspection of reinforcing steel rods in prestressed concrete |
-
1987
- 1987-04-15 GB GB8709033A patent/GB2203549B/en not_active Expired - Lifetime
-
1988
- 1988-10-18 WO PCT/GB1988/000876 patent/WO1990004779A1/fr unknown
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4087749A (en) * | 1977-01-25 | 1978-05-02 | The United States Of America As Represented By The Secretary Of The Army | Method and apparatus for normalizing the outputs of sequentially scanned magnetic flaw detectors |
US4531091A (en) * | 1982-03-29 | 1985-07-23 | The United States Of America As Represented By The Secretary Of Transportation | Magnetic inspection of reinforcing steel using sensor array |
US4481809A (en) * | 1983-08-29 | 1984-11-13 | Labate M D | Method and apparatus for monitoring erosion in gas stirring devices in molten metal ladles |
DE3418066A1 (de) * | 1984-05-16 | 1985-11-21 | Fa. Hermann Nadermann, 4100 Duisburg | Korrosions-testgeraet fuer magnetisierbares stahlblech |
GB2169084A (en) * | 1984-12-21 | 1986-07-02 | Nukem Gmbh | A device for the non-destructive testing of ferromagnetic bodies and a process for producing values for adjusting the device into an initial statee for testing determined by the respective test samples |
EP0238209A2 (fr) * | 1986-03-17 | 1987-09-23 | United Kingdom Atomic Energy Authority | Détection de discontinuités magnétiques |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2001069204A2 (fr) * | 2000-03-14 | 2001-09-20 | British Nuclear Fuels Plc | Ameliorations apportees ou relatives a l'analyse de courant |
WO2001069204A3 (fr) * | 2000-03-14 | 2002-01-24 | British Nuclear Fuels Plc | Ameliorations apportees ou relatives a l'analyse de courant |
US6861853B2 (en) | 2000-03-14 | 2005-03-01 | British Nuclear Fuels Plc | Investigating corrosion |
US6888359B2 (en) | 2000-03-14 | 2005-05-03 | British Nuclear Fuels Plc | Investigating current |
US6982563B2 (en) | 2000-11-09 | 2006-01-03 | British Nuclear Fuels Plc | Monitoring of corrosion induced loss of material by means of a plurality of electrical resistance measurements (field signature method, electrical resistance tomography) |
CN101788521A (zh) * | 2010-03-19 | 2010-07-28 | 南京工业大学 | 金属腐蚀状况在线检测方法及其检测仪器 |
Also Published As
Publication number | Publication date |
---|---|
GB2203549A (en) | 1988-10-19 |
GB2203549B (en) | 1991-05-01 |
GB8709033D0 (en) | 1987-05-20 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
AU595748B2 (en) | Magnetic flux leakage probe with radially offset coils for use in nondestructives testing of pipes and tubes | |
KR0151726B1 (ko) | 지하도체의 위치 및 방향을 결정하는 방법 및 장치 | |
US5914596A (en) | Coiled tubing inspection system | |
IE49312B1 (en) | Casing inspection with magnetic permeability correction | |
EP0787980A3 (fr) | Mesure de la charge dans une pièce et surveillance de l'intégrité de cette pièce | |
ES8702657A1 (es) | Procedimiento para detectar, por corrientes de foucault, de-fectos superficiales de semi-productos metalurgicos | |
US6854336B2 (en) | Measurement of stress in a ferromagnetic material | |
WO1990004779A1 (fr) | Detection de la corrosion du metal | |
CA1166696A (fr) | Controle non destructif d'articles ferromagnetiques | |
WO1982000718A1 (fr) | Procede de detection, de preference en continu, de la presence de fissures, de la formation de fissures et du developpement de fissures dans des constructions | |
CN1208617C (zh) | 奥氏体不锈钢管内氧化物的磁性无损检测方法及装置 | |
WO1998016842A1 (fr) | Dispositif d'examen de materiel tubulaire enroule | |
US20030034776A1 (en) | Method and facility for storing and indexing web browsing data | |
US4130791A (en) | Automatic pipe depth locator | |
EP0441074A3 (fr) | Capteur inductif et dispositifs de mesure du déplacement d'un organ mobile | |
KR20060070004A (ko) | 다수개의 센서가 구비된 지하매설물 탐지기 | |
EP0274450A2 (fr) | Dispositif pour mesurer la proximité d'un objet métallique | |
EP0602039B1 (fr) | Procede de mesure des contraintes mecaniques et des conditions de fatigue dans l'acier | |
KR20000036977A (ko) | 자기장을 이용한 매설 배관 위치 측정 시스템 | |
JPH0750144B2 (ja) | 部分放電位置標定方法 | |
GB2200216A (en) | Measuring proximity of a metal object | |
SU1562837A1 (ru) | Магнитный дефектоскоп | |
SU1659942A1 (ru) | Способ обнаружени неоднородности магнитного пол и устройство дл его осуществлени | |
JP2519501Y2 (ja) | 磁気探傷器 | |
JP3521157B2 (ja) | 二重管の近接距離測定方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AU US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE FR GB IT LU NL SE |