CN102252168B - Accurate positioning and detecting method and device for damages of underground metal pipeline anticorrosive coating - Google Patents
Accurate positioning and detecting method and device for damages of underground metal pipeline anticorrosive coating Download PDFInfo
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- CN102252168B CN102252168B CN2011102009717A CN201110200971A CN102252168B CN 102252168 B CN102252168 B CN 102252168B CN 2011102009717 A CN2011102009717 A CN 2011102009717A CN 201110200971 A CN201110200971 A CN 201110200971A CN 102252168 B CN102252168 B CN 102252168B
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Abstract
The invention relates to an accurate positioning and detecting method and device for damages of an underground metal pipeline anticorrosive coating. The method comprises the following steps: a current interrupter periodically turns on or off a constant current source through the constant current source, and provides excitation signals for an underground pipeline; the ground voltages of two points along the underground pipeline route are measured by utilizing two saturation copper sulfate reference electrode detection canes which are connected with a signal measurement processor respectively; the signal measurement processor measures, records and displays the turn-on and turn-off of the pipe ground voltages; and the position of the damaged part of the underground pipeline can be determined according to the pipe ground turn-on and turn-off voltages. Through the method, the position of the damage point of the anticorrosive coating can be confirmed accurately, the detection accuracy of the damage for the underground pipeline anticorrosive coating is improved, and important guarantee is provided for mastering the normal operation situation of the pipeline, ensuring the safe operation of the pipeline and the convenience for pipeline maintenance and management.
Description
Technical field
The present invention relates to the damaged method and apparatus of the buried metallic conduit anticorrosive coat of accurate detection and localization.
Background technology
Buried metallic conduit transports various media and working pressure is high; It is big to pass through environmental change on the way; Mostly adopt external anti-corrosion layer to cover at present and carry out pipeline corrosion protection, influenced by various factors, anticorrosive coat can occur aging and damaged; How to confirm that aging, the damaged and infiltration position of anticorrosive coat is to reduce the corrosive pipeline risk with timely repairing, thereby guarantee one of necessary condition of buried metallic conduit safe operation.
Present buried metallic conduit operational management is mostly adopted the variation of observing flow, force value to wait to judge whether pipeline damaged the leakage taken place, and fails to play the effect of prevention piping failure, causes the way train medium to run off; And the leakage to small is insensitive, can not accurately learn pipe leakage point position, and the expense that the later stage excavation is changed pipeline is high, workload is big.Safe operation and convenient for maintaining management for guaranteeing pipeline need to be grasped the operation conditions of pipeline at ordinary times.Standard pipe earth potential (P/S) method of testing commonly used at present only obtains data at predetermined measuring point usually, can not accurately obtain damage location.
Summary of the invention
The purpose of this invention is to provide a kind of buried metallic conduit anticorrosive coat damaged accurately position finding and detection method and the device that can accurately locate anticorrosive coat breaking point position.
Technical solution of the present invention is:
The damaged accurately position finding and detection method of buried metallic conduit anticorrosive coat; Utilize constant current source periodically to turn on and off constant current source and pumping signal is provided to buried pipe through the current interruptions device; Utilize two copper/saturated copper sulphate contrast electrodes that link to each other with the signal measurement processor respectively to visit the cane measurement and move towards 2 ground voltage along buried pipe; The signal measurement processor is measured, is write down and show and turns on and off the pipe ground voltage, according to turning on and off the position that voltage can be judged the breakage of buried pipe with managing.
Use the device of said method to the damaged accurate detection and localization of buried metallic conduit anticorrosive coat:
It comprises pumping signal device and signal supervisory instrument; For buried pipe with cathodic protection system; The pumping signal device is made up of ground connection anode, cathodic protection rectifier, buried pipe detective pole and current interruptions device; Being embedded in the underground ground connection anode that is connected with the earth is connected with the positive pole of cathodic protection rectifier through lead; Inserting the buried pipe detective pole that underground and buried metallic conduit links to each other links to each other with an end of current interruptions device through lead; The other end of current interruptions device links to each other with the negative pole of cathodic protection rectifier, and buried pipe detective pole, current interruptions device, cathodic protection rectifier and ground connection anode are connected to form the pumping signal loop in order; For the buried pipe that does not have cathodic protection system; The pumping signal device is made up of ground connection anode, external constant current source, buried pipe detective pole and current interruptions device; The positive pole of external constant current source links to each other with an end of current interruptions device through lead; The other end of current interruptions device through lead be embedded in ground connection anode underground and that the earth is connected and link to each other; Insert the buried pipe detective pole that underground and buried metallic conduit links to each other and link to each other with the negative pole of constant current source through lead, buried pipe detective pole, constant current source, current interruptions device and ground connection anode are connected to form the pumping signal loop in order; Signal supervisory instrument visits cane by two copper/saturated copper sulphate contrast electrodes and the signal measurement processor constitutes, and two signal input parts of signal measurement processor are visited cane with two copper/saturated copper sulphate contrast electrodes respectively and linked to each other.
Technique effect of the present invention is: this method can accurately be located the position of anticorrosive coat breaking point; Improved the damaged accuracy in detection of buried pipe anticorrosive coat; For grasping the operation conditions of pipeline, guarantee that the safe operation of pipeline and convenient for maintaining management provide important assurance.The antijamming capability of this method is higher than prior standard pipe-to-soil potential method and Pearson came method.Use this method that buried metallic conduit is detected, can realize the complete detection of buried metallic conduit operation conditions, can avoid the generation of accidents such as booster effectively.This detection method is called as DC voltage gradient (DCVG; Direct Current Voltage Gradient) method; Current method or close spacing potential method are confirmed on the basis of the damaged pipeline section of buried pipe anticorrosive coat in adopting pipe; It calculates the defective equivalent diameter, realizes the maintenance to buried pipe with lower cost.It is low that pick-up unit has cost simple in structure, advantage easy for operation.
The beneficial effect of DC voltage gradient:
1) compare with classic method, the DC voltage gradient method is high to the damaged bearing accuracy of anticorrosive coat, and anti-interference is good, applied widely, can under different geological (comprising the desert, asphalt flooring etc.) situation, effectively detect.
2) method of employing equivalent circular can be carried out classified estimation to different damaged grades, confirms the damaged order of severity and service sequence.
Description of drawings
Fig. 1 is the system construction drawing that the embodiment of the invention one buried pipe detects;
Fig. 2 is the system construction drawing that the embodiment of the invention two buried pipes detect;
Fig. 3 is that embodiment of the invention signal processor and display cell structure are formed;
Fig. 4 visits the structure of cane for embodiment of the invention reference;
Fig. 5 is embodiment of the invention signal processor signal processing flow figure;
Fig. 6 is the damaged testing result synoptic diagram of embodiment of the invention buried pipe anticorrosive coat.
Embodiment
Like Fig. 1, shown in Figure 2, the concrete steps of the damaged accurately position finding and detection method of buried metallic conduit anticorrosive coat are following:
1), pumping signal inserts: if there is cathodic protection system in buried pipe; Then directly break off being connected of cathodic protection rectifier 2 negative poles and buried pipe detective pole 3; Insert current interruptions device 4 therebetween, make and form the pumping signal loop between ground connection anode 1, cathodic protection rectifier 2, current interruptions device 4, buried pipe detective pole 3 and the buried pipe; If there is not cathodic protection system in buried pipe; Then need external constant current source 5, ground connection anode 1 and buried pipe detective pole 3; Imbed ground connection anode 1 underground; Buried pipe detective pole 3 inserts and undergroundly well contacts with buried pipe, and ground connection anode 1, current interruptions device 4, external constant current source 5 and buried pipe detective pole 3 are connected into buried pipe pumping signal loop, and current interruptions device 4 is connected between external constant current source 5 positive poles and the ground connection anode 1;
2), signal supervisory instrument inserts: two copper/saturated copper sulphate contrast electrodes spy canes 6 are connected respectively on two measurement cables of signal measurement processor 7;
3), input, record and demonstration: open cathodic protection rectifier 2 or external constant current source 5 and current interruptions device 4, survey crew is held two copper/saturated copper sulphate contrast electrodes and is visited cane 6, and the signal access point is walked along pipeline dorsad; Visit cane directly over pipeline one in front and one in back at a distance of 1～2m; Cane point kiss the earth is parallel to pipeline traverse measurement face of land voltage gradient and changes, and takes place by the counter-rotating that just is biased to negative bias if find the high sensitivity millivolt voltage table of signal measurement processor; Then reduce to detect spacing; The registration that finds voltage table is zero A point, is that starting point is moved towards vertical direction with pipeline and carried out above-mentioned operation in the edge again with the A point then, and the registration that finds high sensitivity millivolt voltage table is zero B point; The B point promptly be positioned at the buried pipe breaking point directly over, the exact position that records piping failure thus is so that post-processed;
4), qualitative detection: the B point to record is the center, dwindles two distances of visiting cane and measures the attenuation rate of pipe-to-soil potential with two spy canes and signal measurement processor 7, confirms solution thereby can judge buried pipe at the damaged degree of this point.
Long fixed frequency work of time short with the time of connecting during current interruptions device 4 work, that turn-off is (as connecting 0.3 second; Turn-offed 0.7 second; The time that current interruptions device 4 is connected is less than the turn-off time), current interruptions device 4 asymmetrical period property break-makes can be eliminated in the testing process other direct current undesired signals to the influence of testing result.
Use said method to the damaged pinpoint device of buried metallic conduit anticorrosive coat:
Embodiment one; As shown in Figure 1; It comprises pumping signal device and signal supervisory instrument; For buried pipe with cathodic protection system; The pumping signal device is made up of ground connection anode 1, cathodic protection rectifier 2, buried pipe detective pole 3 and current interruptions device 4, is embedded in the underground ground connection anode 1 that is connected with the earth and is connected through the positive pole of lead with cathodic protection rectifier 2, inserts the buried pipe detective pole 3 that underground and buried metallic conduit links to each other and links to each other with an end of current interruptions device 4 through lead; The other end of current interruptions device 4 links to each other with the negative pole of cathodic protection rectifier 2, and buried pipe detective pole 3, current interruptions device 4, cathodic protection rectifier 2 and ground connection anode 1 are connected to form the pumping signal loop in order; Signal supervisory instrument is visited cane 6 by two copper/saturated copper sulphate contrast electrodes and is constituted with signal measurement processor 7, and two signal input parts of signal measurement processor 7 are visited cane 6 with two copper/saturated copper sulphate contrast electrodes respectively and linked to each other.
Like Fig. 3, shown in Figure 5; Signal measurement processor 7 is made up of sampling holder, central control processor, clock, DA converter and high sensitivity millivolt voltage table; Sampling holder, clock and DA converter link to each other with central control processor respectively, and the DA converter links to each other with high sensitivity millivolt voltage table.
As shown in Figure 4; The copper/saturated copper sulphate contrast electrode is visited the top of cane 6 for copper/saturated copper sulphate solution contrast electrode 61 is housed; The more sharp-pointed ferrule 62 that the bottom for the benefit of contacts with ground, ferrule 62 appearances are covered the copper layer, are electrically connected with copper conductor between contrast electrode 61 and ferrule 62 two parts.
Embodiment two; As shown in Figure 2; With the difference of embodiment one be; For the buried pipe that does not have cathodic protection system; The pumping signal device is made up of ground connection anode 1, external constant current source 5, buried pipe detective pole 3 and current interruptions device 4, and the positive pole of external constant current source 5 is connected with an end of current interruptions device 4 through lead, the other end of current interruptions device 4 through lead be embedded in ground connection anode 1 underground and that the earth is connected and link to each other; Insert the buried pipe detective pole 3 that underground and buried metallic conduit links to each other and link to each other with the negative pole of external constant current source 5 through lead, buried pipe detective pole 3, external constant current source 5, current interruptions device 4 and ground connection anode 1 are connected to form the pumping signal loop in order.
The pipeline electric current that DC voltage gradient (DCVG, Direct Current Voltage Gradient) method applies flows in the external agency that is in contact with it through damaged uncoated dot, thereby on the ground of breakage, forms an electric potential gradient field.Breakage is big more, and breakage loss electric current is big more; Zone apart from anticorrosive coat is damaged is near more, and voltage gradient will become greatly and be more concentrated.
Ultimate principle of the present invention and measurement implementation step: like Fig. 5, shown in Figure 6, the locality is buried ducted electric current and is flowed in the external agency soil that is in contact with it through damaged uncoated dot, thereby on the ground of breakage, forms a DC potential gradient fields.Breakage is big more, and breakage loss electric current is big more; Zone apart from anticorrosive coat is damaged is near more, and voltage gradient will become greatly and be more concentrated.Survey crew is Fig. 1, the direction of arrow shown in Figure 2 walking directly over the pipeline; Use two copper/saturated copper sulphate references to visit the cane kiss the earth and carry out the electric potential gradient detection; When survey crew during near breaking point; Be presented on the high sensitivity milivoltmeter through voltage between two contrast electrodes that amplify, the also needle deflection that responds of pulse electric current is split/is closed to milivoltmeter; In the place ahead of breakage, milivoltmeter pointer positive deflection is through after the breakage; Pointer is deflection in the opposite direction; Along with reducing gradually away from damaged deflection, then visit the cane distance to about 0.3 meter through dwindling, oppositely measure again; Can find pointer almost in the position at place at zero point, then damaged being positioned under the middle part of two electrodes.Be accurate location, on the direction vertical with primary detection direction of travel, do same detection, the intersection point of twice detection of straight lines is exactly the source of voltage gradient, this point be positioned at breakage directly over, realized accurate location to the anticorrosive coat defective.
Claims (2)
1. the damaged accurately position finding and detection method of buried metallic conduit anticorrosive coat; It is characterized in that: utilize constant current source periodically to turn on and off constant current source and pumping signal is provided to buried pipe through the current interruptions device; Utilize two copper/saturated copper sulphate contrast electrodes that link to each other with the signal measurement processor respectively to visit the cane measurement and move towards 2 ground voltage along buried pipe; The signal measurement processor is measured, is write down and show and turns on and off the pipe ground voltage; According to turning on and off the position that voltage can be judged the breakage of buried pipe, concrete steps are following with managing:
1), pumping signal inserts: if there is cathodic protection system in buried pipe; Then directly break off being connected of cathodic protection rectifier (2) negative pole and buried pipe detective pole (3); Insert current interruptions device (4) therebetween, make and form the pumping signal loop between ground connection anode (1), cathodic protection rectifier (2), current interruptions device (4), buried pipe detective pole (3) and the buried pipe; If there is not cathodic protection system in buried pipe; Then need external constant current source (5), ground connection anode (1) and buried pipe detective pole (3); Imbed ground connection anode (1) underground; Buried pipe detective pole (3) insertion is underground well to be contacted with buried pipe; Ground connection anode (1), current interruptions device (4), external constant current source (5) and buried pipe detective pole (3) are connected into buried pipe pumping signal loop, and current interruptions device (4) is connected between external constant current source (5) positive pole and the ground connection anode (1);
2), signal supervisory instrument inserts: two copper/saturated copper sulphate contrast electrodes spy canes (6) are connected respectively on two measurement cables of signal measurement processor (7);
3), input, record and demonstration: open cathodic protection rectifier (2) or external constant current source (5) and current interruptions device (4), survey crew is held two copper/saturated copper sulphate contrast electrodes and is visited cane (6), and the signal access point is walked along pipeline dorsad; Visit cane directly over pipeline one in front and one in back at a distance of 1～2m; Cane point kiss the earth is parallel to pipeline traverse measurement face of land voltage gradient and changes, and takes place by the counter-rotating that just is biased to negative bias if find the high sensitivity millivolt voltage table of signal measurement processor; Then reduce to detect spacing; The registration that finds voltage table is zero A point, is that starting point is moved towards vertical direction with pipeline and carried out above-mentioned operation in the edge again with the A point, and the registration that finds high sensitivity millivolt voltage table is zero B point; The B point promptly be positioned at the buried pipe breaking point directly over, the exact position that records piping failure thus is so that post-processed;
4), qualitative detection: the B point to record is the center, dwindles two distances of visiting cane and measures the attenuation rate of pipe-to-soil potential with two spy canes and signal measurement processor (7), confirms solution thereby can judge buried pipe at the damaged degree of this point.
2. the damaged accurately position finding and detection method of buried metallic conduit anticorrosive coat as claimed in claim 1 is characterized in that long fixed frequency work of time short with the time of connecting when said current interruptions device (4) is worked, that turn-off.
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