Steel Pipeline Anti-Corrosion Coating Detection Device and Detection Method

Abstract

The present invention discloses an anti-corrosion layer detection device and a detection method for steel pipelines. The detection device includes: a flexible conductive contact network, an anti-corrosion layer leakage current detector, a metal test piece, an anti-corrosion layer detector transmitter, and a grounding rod; wherein, the flexible conductive contact network is connected to both the anti-corrosion layer leakage current detector and the steel pipeline to be detected, and the anti-corrosion layer leakage current detector is also connected to the metal test piece; the anti-corrosion layer detector transmitter is connected to the steel pipeline to be detected, and the anti-corrosion layer detector transmitter is also connected to the grounding rod, and the grounding rod is grounded.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline detection, and in particular, to a steel pipeline anticorrosion layer detection device and a detection method. Background Art

[0002] At present, for non-excavation positioning detection of buried steel pipeline anticorrosion layer breakpoints, generally, a leakage detection signal is added to the pipeline through an anticorrosion layer detector, and the leakage detection signal is received on the ground by using an A-frame or the human body capacitance method. If the detector is directly above the anticorrosion layer breakpoint, the receiver will generate an obvious signal change, and non-excavation detection and positioning of suspected non-excavation breakpoints of the anticorrosion layer are carried out according to this signal change. If it is necessary to detect the breakpoint of the steel pipeline anticorrosion layer after excavation (except for those visible to the naked eye), generally, an electric spark detector is used. A certain voltage is applied to the surface of the anticorrosion layer through a detection probe. If there is a breakpoint with exposed iron, an electric spark breakdown will occur between the probe and the metal body, and the detector will alarm. It uses the principle of discharging voltage to steel.

[0003] For the excavation verification of suspected breakpoints of buried steel pipeline anticorrosion layers, the prior art generally uses ground detection and electric spark detection after excavation. However, the anticorrosion layer detector used for ground detection cannot detect the anticorrosion layer breakpoints on the excavated pipeline and must be backfilled before detection; the electric spark detector can only detect the anticorrosion layer breakpoints in the radial direction of the anticorrosion layer. In fact, some anticorrosion layer breakpoints are covered by a relatively large area of newly added repair materials on the outer layer. Although the anticorrosion layer breakpoint is far from the edge of the repair materials, due to various reasons, there are voids in the newly added repair materials, allowing groundwater to penetrate into the voids and reach the anticorrosion layer breakpoint, resulting in a leakage situation. The leakage path of this leakage phenomenon is lengthened, and the leakage path is in the axial direction. According to the current technology and instruments, this kind of leakage situation cannot be detected. Summary of the Invention

[0004] An embodiment of the present invention provides a steel pipeline anticorrosion layer detection device and a detection method, which solve the problems that the electric spark detector cannot completely detect the leakage position and the damage degree of the anticorrosion layer.

[0005] To achieve the above object, an embodiment of the present invention provides a steel pipeline anticorrosion layer detection device, including: a flexible conductive contact network, an anticorrosion layer leakage current detector, a metal test piece, an anticorrosion layer detector transmitter, and a grounding rod;

[0006] Wherein, the flexible conductive contact network is connected to both the anticorrosion layer leakage current detector and the steel pipeline to be measured, and the anticorrosion layer leakage current detector is also connected to the metal test piece; the anticorrosion layer detector transmitter is connected to the steel pipeline to be measured, and the anticorrosion layer detector transmitter is also connected to the grounding rod, and the grounding rod is grounded;

[0007] The flexible conductive catenary is used to adhere to the surface of the anti-corrosion layer of the steel pipeline to be tested after absorbing water and move circumferentially and axially to find the suspected break points on the anti-corrosion layer of the steel pipeline to be tested; the transmitter of the anti-corrosion layer detector is used to transmit a leakage detection signal current, and in the case of leakage of the suspected break point on the anti-corrosion layer of the steel pipeline to be tested, the flexible conductive catenary, the anti-corrosion layer leakage current detector, the metal test piece and the grounding rod form a current path; the anti-corrosion layer leakage current detector is used to measure the leakage current passing through the metal test piece, and then evaluate the degree of anti-corrosion layer breakage and leakage of the steel pipeline to be tested according to the magnitude of the leakage current;

[0008] Evaluating the degree of anti-corrosion layer breakage and leakage of the steel pipeline to be tested according to the magnitude of the leakage current specifically includes:

[0009] If the value of the leakage current is greater than the first breakage threshold, there is a break in the anti-corrosion layer of the steel pipeline to be tested at the suspected break point;

[0010] If the value of the leakage current is greater than the second breakage threshold, there is a break in the anti-corrosion layer of the steel pipeline to be tested at the suspected break point that exposes the metal body of the steel pipeline to be tested; the second breakage threshold is greater than the first breakage threshold.

[0011] As an improvement of the above solution, the steel pipeline anti-corrosion layer detection device further includes a surface potential gradient detector, and two electrodes of the surface potential gradient detector are connected to the surrounding soil of the metal test piece, and the two electrodes and the metal test piece are on the same straight line;

[0012] The surface potential gradient detector is used to detect the potential gradient of the soil around the metal test piece, and then evaluate the degree of anti-corrosion layer breakage and leakage of the steel pipeline to be tested according to the potential gradient.

[0013] As an improvement of the above solution, the metal test piece is a steel test piece, which is used to guide the leakage current of the anti-corrosion layer of the steel pipeline to be tested into the ground, so that a potential gradient is formed between the steel test piece and the surrounding soil centered on the steel test piece.

[0014] As an improvement of the above solution, the surface area of the steel test piece is 10mm 2 .

[0015] An embodiment of the present invention further provides a method for detecting the anti-corrosion layer of a steel pipeline, which is applied to the steel pipeline anti-corrosion layer detection device described in the above embodiment, and the method includes:

[0016] Move circumferentially and axially on the surface of the anti-corrosion layer of the steel pipeline to be tested to find the suspected damaged points on the anti-corrosion layer of the steel pipeline to be tested;

[0017] Emit a leakage detection signal current. In the case of leakage of the suspected damaged point on the anti-corrosion layer of the steel pipeline to be tested, form a current path among the flexible conductive contact network, the anti-corrosion layer leakage current detector, the metal test piece and the grounding rod;

[0018] Measure the leakage current passing through the metal test piece;

[0019] If the value of the leakage current is greater than the first damage threshold, there is damage at the suspected damaged point on the anti-corrosion layer of the steel pipeline to be tested;

[0020] If the value of the leakage current is greater than the second damage threshold, there is damage exposing the metal body of the steel pipeline to be tested at the suspected damaged point on the anti-corrosion layer of the steel pipeline to be tested; the second damage threshold is greater than the first damage threshold.

[0021] As an improvement of the above solution, after "If the value of the leakage current is greater than the second damage threshold, there is damage exposing the metal body of the steel pipeline to be tested at the suspected damaged point on the anti-corrosion layer of the steel pipeline to be tested", it further includes:

[0022] Detect the potential gradient of the soil around the metal test piece;

[0023] Evaluate the degree of leakage of the anti-corrosion layer of the steel pipeline to be tested according to the potential gradient.

[0024] As an improvement of the above solution, before "Move circumferentially and axially on the surface of the anti-corrosion layer of the steel pipeline to be tested to find the suspected damaged points on the anti-corrosion layer of the steel pipeline to be tested", it further includes:

[0025] Clean the surface of the steel pipeline to be tested and retain moisture on the surface of the steel pipeline to be tested;

[0026] Make the flexible conductive contact network absorb water and adhere to the surface of the steel pipeline to be tested.

[0027] The steel pipeline anticorrosion layer detection device and detection method provided by the present invention move circumferentially and axially on the surface of the anticorrosion layer of the steel pipeline to be detected through a flexible conductive contact network to find suspected damage points on the anticorrosion layer of the steel pipeline to be detected; a leakage detection signal current is emitted. If the suspected damage point on the anticorrosion layer of the steel pipeline to be detected is damaged and leaks electricity, then an electric current path will be formed between the flexible conductive contact network, the anticorrosion layer leakage current detector, the metal test piece and the grounding rod. Then, the anticorrosion layer leakage current detector measures the leakage current passing through the metal test piece, and then evaluates the degree of damage and leakage of the anticorrosion layer of the steel pipeline to be detected according to the magnitude of the leakage current.

[0028] As can be seen from the above, the above detection device is used to directly detect the damage position and degree of the anticorrosion layer of the excavated steel buried pipeline, and there is no need to backfill again, which reduces the excavation volume while improving the detection speed and accuracy; this device can also perform leakage detection on pipelines using the light-curing strengthening protection method or the anticorrosion layer with a complete overall repaired appearance, avoiding the situation where the quality of the anticorrosion layer cannot be detected and evaluated by using the spark detection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a steel pipeline anticorrosion layer detection device. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Please refer to Figure 1 , an embodiment of the present invention provides a steel pipeline anticorrosion layer detection device, including: a flexible conductive contact network 1, an anticorrosion layer leakage current detector 2, a metal test piece 3, an anticorrosion layer detector transmitter 6 and a grounding rod 7.

[0032] Among them, the flexible conductive contact network 1 is connected to the anticorrosion layer leakage current detector 2 and the steel pipeline to be detected, and the anticorrosion layer leakage current detector 2 is also connected to the metal test piece 3; the anticorrosion layer detector transmitter 6 is connected to the steel pipeline to be detected, and the anticorrosion layer detector transmitter 6 is also connected to the grounding rod 7, and the grounding rod 7 is grounded.

[0033] It should be noted that the flexible conductive catenary 5 is composed of a cotton fabric mixed with a metal conductive network. During detection, the flexible conductive catenary needs to be fully watered. In actual operation, the surface of the anti-corrosion layer 5 of the steel pipeline to be tested also needs to be fully watered and penetrated.

[0034] The flexible conductive catenary 1 is used to adhere to the surface of the anti-corrosion layer 5 of the steel pipeline to be tested after absorbing water and move circumferentially and axially to find the suspected damaged points on the anti-corrosion layer 5 of the steel pipeline to be tested; the transmitter 6 of the anti-corrosion layer detector is used to transmit a leakage detection signal current. When there is a leakage of electricity at the suspected damaged points on the anti-corrosion layer of the steel pipeline to be tested, the flexible conductive catenary 1, the anti-corrosion layer leakage current detector 2, the metal test piece 3 and the grounding rod form a current path; the anti-corrosion layer leakage current detector is used to measure the leakage current passing through the metal test piece 3, and then evaluate the degree of leakage and damage of the anti-corrosion layer 5 of the steel pipeline to be tested according to the magnitude of the leakage current;

[0035] The evaluation of the degree of leakage and damage of the anti-corrosion layer of the steel pipeline to be tested according to the magnitude of the leakage current specifically includes:

[0036] If the value of the leakage current is greater than the first damage threshold, there is damage to the anti-corrosion layer of the steel pipeline to be tested at the suspected damaged point;

[0037] If the value of the leakage current is greater than the second damage threshold, there is damage to the anti-corrosion layer of the steel pipeline to be tested at the suspected damaged point where the metal body of the steel pipeline to be tested is exposed; the second damage threshold is greater than the first damage threshold.

[0038] It should be noted that when the anti-corrosion layer 5 is damaged, the pipeline current in the steel pipeline to be tested will form a current path through the moisture on the surface of the anti-corrosion layer 5, the flexible conductive catenary 1, the metal test piece 3 and the ground. The larger the damaged area of the anti-corrosion layer or the larger the exposed metal of the damaged pipeline, the larger the current flowing through this current path. The anti-corrosion layer leakage current detector 2 is internally provided with a galvanometer resistance, and the magnitude of the current flowing through is calculated by detecting the voltage of this resistance.

[0039] In actual use, the first damage threshold and the second damage threshold can be set to 30 dBuA and 60 dBuA respectively. If the leakage current value is less than 30 dBuA, it is regarded as background noise and there is no damage to the anti-corrosion layer at this detection point; if the leakage current is greater than 30 dBuA, there is damage to the anti-corrosion layer at this detection point; if the leakage current is greater than 60 dBuA, there is damage to the anti-corrosion layer at this detection point where the metal body of the pipeline is exposed.

[0040] The device provided by the embodiment of the present invention can directly detect the position and size of the damaged anti-corrosion layer of the excavated steel buried pipeline, without the need for re-backfilling, reducing the excavation volume and improving the detection speed and accuracy. If it is for the weld joint repair of the steel buried pipeline, the device can perform leakage detection on the suspected damaged points to evaluate the anti-corrosion effect.

[0041] Generally speaking, the device directly detects the position and size of the damaged anti-corrosion layer of the excavated steel buried pipeline, and without the need for re-backfilling, it reduces the excavation volume while improving the detection speed and accuracy; the device can also perform leakage detection on the pipeline with a light-curing enhanced protection method or the anti-corrosion layer of the overall repair, avoiding the situation where the quality of the anti-corrosion layer cannot be detected and evaluated by the spark detection method, and it is an effective supplement to the existing spark detection and evaluation acceptance method for the quality of the anti-corrosion layer.

[0042] Exemplarily, the steel pipeline anti-corrosion layer detection device further includes a surface potential gradient detector 4. Two electrodes of the surface potential gradient detector 4 are connected to the surrounding soil of the metal test piece 3, and the two electrodes and the metal test piece 3 are on the same straight line.

[0043] The surface potential gradient detector 4 is used to detect the potential gradient between the metal test piece 3 and the surrounding soil, and then evaluate the degree of damaged leakage of the anti-corrosion layer of the steel pipeline to be tested according to the potential gradient.

[0044] The surface potential gradient detector mainly detects the IR drop of the soil around the test piece, also called the potential gradient, and evaluates the severity of the damaged anti-corrosion layer by detecting the potential gradient of the soil. In this embodiment, the size of the leakage current of the anti-corrosion layer of the steel buried pipeline is jointly and comprehensively evaluated according to the measurement results of the anti-corrosion layer leakage current flowing out of the anti-corrosion layer and the measurement results of the surface potential gradient, and then the degree of damage of the anti-corrosion layer is evaluated.

[0045] Exemplarily, the metal test piece 3 is a steel test piece, which is used to guide the leakage current of the anti-corrosion layer of the steel pipeline to be tested into the ground, so that the leakage current forms a potential gradient between the steel test piece and the surrounding soil centered on the steel test piece.

[0046] Exemplarily, the surface area of the steel test piece is 10mm 2 .

[0047] The embodiment of the present invention also provides a method for detecting the anti-corrosion layer of a steel pipeline, which is applied to the steel pipeline anti-corrosion layer detection device described in the above embodiment. The method includes:

[0048] S20. Move circumferentially and axially on the surface of the anti-corrosion layer of the steel pipeline to be tested to find the suspected damaged points on the anti-corrosion layer of the steel pipeline to be tested.

[0049] S21. Transmit a leakage detection signal current. When there is a suspected break and leakage at a suspected break point on the anti-corrosion layer of the steel pipeline to be tested, form a current path between the flexible conductive contact network, the anti-corrosion layer leakage current detector, the metal test piece and the grounding rod.

[0050] S22. Measure the leakage current passing through the metal test piece.

[0051] S23. If the value of the leakage current is greater than the first break threshold, there is a break in the anti-corrosion layer of the steel pipeline to be tested at the suspected break point.

[0052] S24. If the value of the leakage current is greater than the second break threshold, there is a break in the anti-corrosion layer of the steel pipeline to be tested at the suspected break point that exposes the metal body of the steel pipeline to be tested; the second break threshold is greater than the first break threshold.

[0053] As an improvement of the above solution, after S24, it further includes:

[0054] S25. Detect the potential gradient of the soil around the metal test piece.

[0055] S26. Evaluate the degree of breakage and leakage of the anti-corrosion layer of the steel pipeline to be tested according to the potential gradient.

[0056] Exemplarily, before moving circumferentially and axially on the surface of the anti-corrosion layer of the steel pipeline to be tested to find the suspected break point on the anti-corrosion layer of the steel pipeline to be tested, it further includes:

[0057] S18. Clean the surface of the steel pipeline to be tested and retain moisture on the surface of the steel pipeline to be tested.

[0058] S19. Make the flexible conductive contact network absorb water and adhere to the surface of the steel pipeline to be tested.

[0059] The steel pipeline anti-corrosion layer detection method provided by the embodiments of the present invention moves circumferentially and axially on the surface of the anti-corrosion layer of the steel pipeline to be tested through a flexible conductive contact network to find the suspected break point on the anti-corrosion layer of the steel pipeline to be tested; transmit a leakage detection signal current. If there is a break and leakage at the suspected break point on the anti-corrosion layer of the steel pipeline to be tested, then a current path will be formed between the flexible conductive contact network, the anti-corrosion layer leakage current detector, the metal test piece and the grounding rod. Then, the anti-corrosion layer leakage current detector measures the leakage current passing through the metal test piece, and then evaluates the degree of breakage and leakage of the anti-corrosion layer of the steel pipeline to be tested according to the magnitude of the leakage current.

[0060] As can be seen from the above, the above detection device is used to directly detect the damaged position and degree of the anti-corrosion layer of the excavated steel buried pipeline, and there is no need to backfill again, which reduces the excavation volume while improving the detection speed and accuracy.

[0061] The above-disclosed are only some preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Those of ordinary skill in the art can understand all or part of the processes of implementing the above embodiments, and the equivalent changes made according to the claims of the present invention still fall within the scope covered by the invention.

Claims

1. An anti-corrosion layer detection device for steel pipelines, characterized in that, Comprising: A flexible conductive catenary, an anticorrosion layer leakage current detector, a metal test piece, an anticorrosion layer detector transmitter, and a grounding rod; Wherein, the flexible conductive catenary is connected to both the anticorrosion layer leakage current detector and the steel pipeline to be measured. The anticorrosion layer leakage current detector is also connected to the metal test piece. The anticorrosion layer detector transmitter is connected to the steel pipeline to be measured, and the anticorrosion layer detector transmitter is also connected to the grounding rod, and the grounding rod is grounded; The flexible conductive catenary is used to adhere to the surface of the anticorrosion layer of the steel pipeline to be measured after absorbing water and move circumferentially and axially to find the suspected damage points on the anticorrosion layer of the steel pipeline to be measured. The anticorrosion layer detector transmitter is used to emit a leakage detection signal current. When there is leakage due to damage at the suspected damage points on the anticorrosion layer of the steel pipeline to be measured, it forms a current path among the flexible conductive catenary, the anticorrosion layer leakage current detector, the metal test piece, and the grounding rod. The anticorrosion layer leakage current detector is used to measure the leakage current passing through the metal test piece, and then evaluate the degree of leakage due to damage of the anticorrosion layer of the steel pipeline to be measured according to the magnitude of the leakage current; The evaluation of the degree of leakage due to damage of the anticorrosion layer of the steel pipeline to be measured according to the magnitude of the leakage current specifically includes: If the value of the leakage current is greater than the first damage threshold, there is damage at the suspected damage point of the anticorrosion layer of the steel pipeline to be measured; If the value of the leakage current is greater than the second damage threshold, there is damage exposing the metal body of the steel pipeline to be measured at the suspected damage point of the anticorrosion layer of the steel pipeline to be measured. The second damage threshold is greater than the first damage threshold.

2. The steel pipeline anticorrosion layer detection device according to claim 1, wherein It further includes a surface potential gradient detector. Two electrodes of the surface potential gradient detector are connected to the surrounding soil of the metal test piece, and the two electrodes are on the same straight line as the metal test piece; The surface potential gradient detector is used to detect the potential gradient of the soil around the metal test piece, and then evaluate the degree of leakage due to damage of the anticorrosion layer of the steel pipeline to be measured according to the potential gradient.

3. The steel pipeline anticorrosion layer detection device according to claim 1 or 2, characterized in that, The metal test piece is a steel test piece, which is used to guide the leakage current of the anticorrosion layer of the steel pipeline to be measured into the ground, so that a potential gradient is formed between the steel test piece and the surrounding soil centered on the steel test piece.

4. The steel pipeline anticorrosion layer detection device according to claim 3, characterized in that The surface area of the steel specimen is 10 mm 2 .

5. A method for detecting the anti-corrosion coating of a steel pipeline, characterized in that, Applied to the steel pipeline anticorrosion layer detection device according to any one of claims 1 to 4, including: Moving circumferentially and axially on the surface of the anticorrosion layer of the steel pipeline to be measured to find the suspected damage points on the anticorrosion layer of the steel pipeline to be measured; Emitting a leakage detection signal current, and when there is leakage due to damage at the suspected damage points on the anticorrosion layer of the steel pipeline to be measured, forming a current path among the flexible conductive catenary, the anticorrosion layer leakage current detector, the metal test piece, and the grounding rod; Measuring the leakage current passing through the metal test piece; If the value of the leakage current is greater than the first damage threshold, there is damage at the suspected damage point of the anticorrosion layer of the steel pipeline to be measured; If the value of the leakage current is greater than the second breakage threshold, there is a break in the anti-corrosion layer of the steel pipeline to be tested, exposing the metal body of the steel pipeline to be tested at the suspected break point; the second breakage threshold is greater than the first breakage threshold.

6. The steel pipeline anticorrosion layer detection method according to claim 5, characterized in that, After the step of if the value of the leakage current is greater than the second breakage threshold, there is a break in the anti-corrosion layer of the steel pipeline to be tested, exposing the metal body of the steel pipeline to be tested at the suspected break point, the method further includes: Detecting the potential gradient of the soil around the metal test piece; Evaluating the degree of leakage of the anti-corrosion layer of the steel pipeline to be tested according to the potential gradient.

7. The steel pipeline anticorrosion layer detection method according to claim 5 or 6, characterized in that, Before the step of moving circumferentially and axially on the surface of the anti-corrosion layer of the steel pipeline to be tested to find the suspected break point on the anti-corrosion layer of the steel pipeline to be tested, the method further includes: Cleaning the surface of the steel pipeline to be tested and retaining moisture on the surface of the steel pipeline to be tested; Making the flexible conductive contact network absorb water and adhere to the surface of the steel pipeline to be tested.

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