A method and device for calibrating the cathodic protection potential of pipelines under apron concrete

Abstract

A method and device for calibrating the cathodic protection potential of pipelines under apron concrete, belonging to the technical field of pipeline cathodic protection technology. The method includes: measuring and obtaining pipeline cathodic protection potential data under different temperature and soil moisture conditions; obtaining a potential correction formula based on the pipeline cathodic protection potential data under different temperature and soil moisture conditions; measuring and obtaining the pipeline cathodic protection measurement potential, temperature, and soil moisture content; and obtaining the pipeline cathodic protection true potential based on the pipeline cathodic protection measurement potential, temperature, soil moisture content, and the potential correction formula. The method comprehensively considers the effects of temperature and soil moisture content on the cathodic protection potential, ensuring the accuracy of potential measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline cathodic protection, and in particular to a method and device for calibrating the cathodic protection potential of a pipeline under apron concrete. Background Art

[0002] The measured data of cathodic protection potential has a linear relationship with temperature. Taking 25℃ as the benchmark, the potential value deviates by 0.9mV for every 1℃ increase or decrease. Conventional reference electrodes are generally buried more than 1 meter deep in the soil. The temperature change at a burial depth of 1 meter in the soil is relatively low, and the error in the measured data can be ignored.

[0003] The reference electrode for the apron pipeline is located in the test well, buried at the same depth as the pipeline, at the end of the test well threading pipe. Since the apron temperature exceeds 70°C in summer, the temperature of the test well directly connected to the apron can reach 50°C at its highest. The existing apron potential measurement method that ignores temperature factors will cause measurement errors of up to tens of mV, and can no longer accurately represent the true protection status of the pipeline.

[0004] In the prior art, for example, Chinese invention patent application No. 202210083417.3 discloses a buried pipeline cathodic protection potential detection system, comprising a processing module, a pipeline potential measurement module connected to the processing module, a copper sulfate reference electrode, and a temperature measurement module. The pipeline potential measurement module is used to measure the measuring end potential of the buried pipeline. The copper sulfate reference electrode is placed in the soil above the buried pipeline and is used to provide a reference end potential. The temperature measurement module is used to measure the ambient temperature of the soil. The processing module is used to obtain a potential compensation value of the copper sulfate reference electrode based on the ambient temperature. The processing module is also used to obtain the cathodic protection potential of the buried pipeline based on the measuring end potential, the reference end potential, and the potential compensation value. The potential compensation value of the copper sulfate reference electrode is obtained by measuring the ambient temperature of the soil, and the potential value measured by the copper sulfate reference electrode is then calibrated to achieve the purpose of accurately assessing the cathodic protection potential of the pipeline.

[0005] However, the high temperature in the test well will also cause rapid evaporation of water, which will have a significant impact on the soil moisture content. Considering only the impact of temperature on the pipeline cathodic protection potential, it is obviously impossible to guarantee the accuracy of the potential measurement. Summary of the Invention

[0006] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and provide a method and device for calibrating the cathodic protection potential of pipelines under apron concrete, which can comprehensively consider the influence of temperature and soil moisture content on the cathodic protection potential and ensure the accuracy of potential measurement.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A method for calibrating the cathodic protection potential of pipelines under apron concrete, comprising:

[0009] Measure and obtain pipeline cathodic protection potential data under different temperatures and soil moisture conditions;

[0010] Obtaining a potential correction formula based on the pipeline cathodic protection potential data under the conditions of different temperatures and different soil moisture contents;

[0011] Measure and obtain pipeline cathodic protection measurement potential, temperature and soil moisture content;

[0012] The real potential of the pipeline cathodic protection is obtained according to the pipeline cathodic protection measurement potential, temperature, soil moisture content and potential correction formula.

[0013] As a preferred embodiment of the present invention, the potential correction formula is specifically:

[0014] U=ɑFa+0.009(T-25)+K(T≥25,0 <a<1,7%<F<40%)

[0015] U=ɑFa+0.009(25-T)+K(T<25,0 <a<1,7%<F<40%)

[0016] Where U is the true potential, F is the soil moisture content, T is the temperature, K is the measured potential, and ɑ and a are the measured coefficients.

[0017] As a preferred embodiment of the present invention, when the pipeline cathodic protection measurement potential, temperature and soil moisture content are measured, if the soil moisture content is lower than a set value, the soil moisture content near the potential measurement probe is adjusted by dripping water, and the pipeline cathodic protection potential after the soil moisture content is adjusted is measured, and the measured potential is converted into the pipeline cathodic protection measurement potential before the soil moisture content is adjusted.

[0018] The present invention also provides a device for calibrating the cathodic protection potential of pipelines under apron concrete, comprising:

[0019] Potential test probe, used to measure the cathodic protection potential of pipelines;

[0020] Temperature probe, used to measure soil temperature;

[0021] Soil moisture probe, used to measure soil moisture;

[0022] A data acquisition module is used to collect and store the measurement data of the potential test probe, the temperature probe and the soil moisture probe;

[0023] The potential calibration module is used to obtain a potential correction formula based on the data from the data acquisition module, and to correct the pipeline cathodic protection measurement potential based on the potential correction formula.

[0024] As a preferred embodiment of the present invention, the potential correction formula is specifically:

[0025] U=ɑFa+0.009(T-25)+K(T≥25,0 <a<1,7%<F<40%)

[0026] U=ɑFa+0.009(25-T)+K(T<25,0 <a<1,7%<F<40%)

[0027] Where U is the true potential, F is the soil moisture content, T is the temperature, K is the measured potential, and ɑ and a are the measured coefficients.

[0028] As the present invention preferably, comprising:

[0029] The water addition control device is used to drip water into the soil to adjust the soil moisture content when the soil moisture content is lower than the set value; the data acquisition device obtains the pipeline cathodic protection potential after the soil moisture content is adjusted, and converts it into the pipeline cathodic protection measurement potential before the soil moisture content is adjusted.

[0030] As a preferred embodiment of the present invention, it further includes a fixing buckle, and the potential test probe, temperature probe, soil moisture probe and water addition control device are all arranged in the fixing buckle.

[0031] As a preferred embodiment of the present invention, the soil moisture probe and the water addition control device are arranged adjacent to each other.

[0032] As a preferred embodiment of the present invention, a tightening screw is provided on the side of the fixing buckle.

[0033] As a preferred embodiment of the present invention, the fixing buckle is specifically made of polytetrafluoroethylene material.

[0034] The advantages of the present invention are:

[0035] 1. Comprehensively consider the influence of temperature and soil moisture on cathodic protection potential to ensure the accuracy of potential measurement;

[0036] 2. Avoid the problem of poor contact of the reference electrode by dripping water on the soil, and use the correction formula to restore the true potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flow chart of a method for calibrating the cathodic protection potential of pipelines under apron concrete provided in this embodiment:

[0038] Figure 2 A schematic diagram of the structure of a cathodic protection potential calibration device for pipelines under apron concrete provided in this embodiment:

[0039] Figure 3A schematic diagram of the structure of the fixing buckle provided in this embodiment;

[0040] In the figure: 1-potential test probe; 2-temperature sensor; 3-soil moisture probe; 4-data acquisition module; 5-potential correction module; 6-water addition control device; 7-fixing buckle; 71-tightening screw. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 1 As shown, this embodiment provides a method for calibrating the cathodic protection potential of pipelines under apron concrete, including:

[0043] Step s1: Measure and obtain pipeline cathodic protection potential data under different temperature and soil moisture conditions. Temperature is generally measured using a temperature probe, soil moisture using a soil moisture probe, and pipeline cathodic protection potential data using a potential test probe. The potential test probe includes a reference electrode, a test piece, and a conductor. The reference electrode includes a glass housing and a saturated copper sulfate solution. The test piece is made of the same material as the pipeline. The temperature probe, soil moisture probe, and potential test probe simultaneously measure data from the same area. To ensure the reliability of the measured data, multiple measurements can be performed, with measurement times set to 1 hour, 6 hours, 12 hours, 24 hours, and 48 hours, respectively.

[0044] Step s2: derive a potential correction formula based on the pipeline cathodic protection potential data under the conditions of different temperatures and different soil moisture contents. Specifically, the data measured in step 1 are analyzed: The effect of temperature on potential is as mentioned in the background art. Taking 25°C as the reference, the potential value deviates by 0.9 mV for every 1°C increase or decrease. Therefore, the correction formula for potential changes with ambient temperature T is:

[0045] U=V+0.009 (T-25) (T≥25)

[0046] U=V+0.009(25-T)(T<25)

[0047] Among them, U is the true potential and V is the measured potential (including the influence of soil moisture content).

[0048] Then, after correcting the measured data using the above correction formula, we can obtain potential data that is only affected by the soil moisture content. Through analysis methods such as establishing a coordinate system, it can be concluded that when the soil moisture content is between 7% and 40%, the potential changes with the moisture content as a power function. When the soil moisture content is greater than 40%, the potential does not change with the moisture content. The correction formula for the potential changing with the soil moisture content F is:

[0049] V=ɑFa+K(0 <a<1,7%<F<40%)

[0050] Where K is the measured potential, and ɑ and a are the measured coefficients.

[0051] In summary, the correction formula for potential changes with ambient temperature T and soil moisture content F can be obtained as follows:

[0052] U=ɑFa+0.009(T-25)+K(T≥25,0 <a<1,7%<F<40%)

[0053] U=ɑFa+0.009(25-T)+K(T<25,0 <a<1,7%<F<40%)。

[0054] Where U is the true potential, F is the soil moisture content, T is the temperature, K is the measured potential, and ɑ and a are the measured coefficients.

[0055] Step s3: During actual measurement, the pipeline cathodic protection measurement potential, temperature and soil moisture content are measured and obtained.

[0056] Step s4, obtaining the pipeline cathodic protection real potential based on the pipeline cathodic protection measured potential, temperature, soil moisture content and potential correction formula.

[0057] Specifically, in step s3, during the actual potential measurement process, due to the high apron temperature, the soil moisture can easily evaporate rapidly. Once the soil moisture content is lower than 15%, the reference electrode and the soil may lose contact, affecting the normal acquisition of the potential data. Therefore, we need to drip water on the soil near the reference electrode to adjust the soil moisture content to 15% or above, and then measure the potential data normally. However, the potential data measured by dripping water is not the actual measured potential data, so it is necessary to convert the potential after the soil moisture content is adjusted to the measured potential before the soil moisture content is adjusted according to the correction formula for the change of potential with soil moisture content. Finally, in step s4, the converted measured potential is overall corrected to obtain the true potential.

[0058] In addition, since the soil moisture near the reference electrode and the moisture content measured by the soil moisture probe do not necessarily remain synchronized after water dripping, in order to ensure data accuracy, the measured potential data and soil moisture content must not change significantly within the set time, or the rate of change is less than the set value, before the measured data is considered accurate and usable. Generally speaking, the longer the above set time, the more stable and accurate the data. However, since water dripping only affects the soil near the reference electrode, the moisture in this part of the soil will gradually penetrate into other parts of the soil after the dripping, causing the soil moisture content to drop again. Therefore, the above set time also needs to take this issue into consideration and should not be set too long.

[0059] like Figure 2 As shown, this embodiment also provides a cathodic protection potential calibration device for pipelines under apron concrete, comprising:

[0060] Potential test probe 1, used to measure the cathodic protection potential of the pipeline; includes a reference electrode, a test piece and a wire. The reference electrode includes a glass shell and a saturated copper sulfate solution. The test piece is made of the same material as the pipeline.

[0061] Temperature probe 2, used to measure soil temperature;

[0062] Soil moisture probe 3, used to measure soil moisture;

[0063] The data acquisition module 4 is connected to the potential test probe 1, the temperature probe 2 and the soil moisture probe 3, and is used to collect and store the measurement data of the potential test probe, the temperature probe and the soil moisture probe;

[0064] The potential calibration module 5 is used to obtain a potential correction formula based on the data from the data acquisition module 4, and to correct the measured potential of the pipeline cathodic protection according to the potential correction formula. The process of deriving the potential correction formula is as follows: the effect of temperature on potential is as mentioned in the background technology. Taking 25°C as the reference, the potential value is biased by 0.9mV for every 1°C increase or decrease. Therefore, the correction formula for the potential when the ambient temperature T changes is:

[0065] U=V+0.009 (T-25) (T≥25)

[0066] U=V+0.009(25-T)(T<25)

[0067] Among them, U is the true potential and V is the measured potential (including the influence of soil moisture content).

[0068] Then, after correcting the measured data using the above correction formula, we can obtain potential data that is only affected by the soil moisture content. Through analysis methods such as establishing a coordinate system, it can be concluded that when the soil moisture content is between 7% and 40%, the potential changes with the moisture content as a power function. When the soil moisture content is greater than 40%, the potential does not change with the moisture content. The correction formula for the potential changing with the soil moisture content F is:

[0069] V=ɑFa+K(0 <a<1,7%<F<40%)

[0070] Where K is the measured potential, and ɑ and a are the measured coefficients.

[0071] In summary, the correction formula for potential changes with ambient temperature T and soil moisture content F can be obtained as follows:

[0072] U=ɑFa+0.009(T-25)+K(T≥25,0 <a<1,7%<F<40%)

[0073] U=ɑFa+0.009(25-T)+K(T<25,0 <a<1,7%<F<40%)。

[0074] Where U is the true potential, F is the soil moisture content, T is the temperature, K is the measured potential, and ɑ and a are the measured coefficients.

[0075] In addition, the device also includes:

[0076] The water addition control device 6 is used to drip water into the soil to adjust the soil moisture content when the soil moisture content is lower than a set value. The data acquisition device obtains the pipeline cathodic protection potential after the soil moisture content is adjusted and converts it into the pipeline cathodic protection measurement potential before the soil moisture content is adjusted. Specifically, during the actual potential measurement process, due to the high apron temperature, soil moisture can easily evaporate rapidly. Once the soil moisture content is lower than 15%, the reference electrode may lose contact with the soil, affecting the normal acquisition of potential data. Therefore, it is necessary to drip water into the soil near the reference electrode to adjust the soil moisture content to 15% or above, and then measure the potential data normally. However, the potential data measured by dripping water is not the actual measured potential data. Therefore, it is necessary to convert the potential after the soil moisture content is adjusted to the measured potential before the soil moisture content is adjusted according to the correction formula for potential change with soil moisture content. Finally, the converted measured potential is corrected as a whole using the potential correction formula to obtain the true potential.

[0077] In addition, since the soil moisture near the reference electrode and the moisture content measured by the soil moisture probe do not necessarily remain synchronized after water dripping, in order to ensure data accuracy, the measured potential data and soil moisture content must not change significantly within the set time, or the rate of change is less than the set value, before the measured data is considered accurate and usable. Generally speaking, the longer the above set time, the more stable and accurate the data. However, since water dripping only affects the soil near the reference electrode, the moisture in this part of the soil will gradually penetrate into other parts of the soil after the dripping, causing the soil moisture content to drop again. Therefore, the above set time also needs to take this issue into consideration and should not be set too long.

[0078] like Figure 3 As shown, the potential test probe 1, temperature probe 2, soil moisture probe 3, and water addition control device 6 are all housed within a fixing clip 7, allowing them to be simultaneously inserted into the same area of ​​the soil, ensuring the reliability of the measured data. To facilitate assembly and disassembly, a tightening screw 71 is provided on the side of the fixing clip 7 to tighten the measuring components. The fixing clip 7 is specifically made of polytetrafluoroethylene, which is not only strong and stable, but also has a low friction coefficient, making it easy to insert into the soil while also being insulated and not affecting potential measurement.

[0079] In order to enable the soil moisture probe to timely sense the change in soil moisture after water is added, the soil moisture probe 3 and the water addition control device 6 are arranged adjacent to each other.

[0080] The above description is merely a preferred embodiment of the present invention, which is one implementation method based on the overall concept of the present invention. The scope of protection of the present invention is not limited to this embodiment. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for calibrating the cathodic protection potential of pipelines under apron concrete, characterized in that: include: Measure and obtain pipeline cathodic protection potential data under different temperatures and soil moisture conditions; According to the pipeline cathodic protection potential data under different temperatures and soil moisture conditions, the potential correction formula is obtained: U=ɑF a +0.009(T-25)+K, where T≥25, 0 <a<1,7%<F<40%; U=ɑF a +0.009(25-T)+K, where T<25, 0 <a<1,7%<F<40%; Where U is the true potential, F is the soil moisture content, T is the temperature, K is the measured potential, and ɑ and a are the measured coefficients; Measure and obtain pipeline cathodic protection measurement potential, temperature and soil moisture content; If the soil moisture content is lower than the set value, the soil moisture content near the potential measurement probe is adjusted by dripping water, the pipeline cathodic protection potential after the soil moisture content adjustment is measured, and it is converted into the pipeline cathodic protection measurement potential before the soil moisture content adjustment; The real potential of the pipeline cathodic protection is obtained according to the pipeline cathodic protection measurement potential, temperature, soil moisture content and potential correction formula.

2. A device for calibrating the cathodic protection potential of pipelines under apron concrete, characterized in that: include: Potential test probe, used to measure the cathodic protection potential of pipelines; Temperature probe, used to measure soil temperature; Soil moisture probe, used to measure soil moisture; A data acquisition module is used to collect and store the measurement data of the potential test probe, the temperature probe and the soil moisture probe; A potential calibration module is used to obtain a potential correction formula based on the data from the data acquisition module, and to correct the measured potential of the pipeline cathodic protection according to the potential correction formula; The potential correction formula is specifically: U=ɑF a +0.009(T-25)+K, where T≥25, 0 <a<1,7%<F<40%; U=ɑF a +0.009(25-T)+K, where T<25, 0 <a<1,7%<F<40%; Where U is the true potential, F is the soil moisture content, T is the temperature, K is the measured potential, and ɑ and a are the measured coefficients; The water addition control device is used to drip water into the soil to adjust the soil moisture content when the soil moisture content is lower than the set value; the data acquisition module obtains the pipeline cathodic protection potential after the soil moisture content is adjusted, and converts it into the pipeline cathodic protection measurement potential before the soil moisture content is adjusted.

3. The cathodic protection potential calibration device for pipelines under apron concrete according to claim 2 is characterized in that: It also includes a fixing buckle, and the potential test probe, temperature sensor, soil moisture probe and water addition control device are all arranged in the fixing buckle.

4. The cathodic protection potential calibration device for pipelines under apron concrete according to claim 3 is characterized in that: The soil moisture probe and the water adding control device are arranged adjacent to each other.

5. The cathodic protection potential calibration device for pipelines under apron concrete according to claim 3 is characterized in that: A tightening screw is provided on the side surface of the fixing buckle.

6. The cathodic protection potential calibration device for pipelines under apron concrete according to claim 3 is characterized in that: The fixing buckle is specifically made of polytetrafluoroethylene material.

Images