Composite probe for cathode protection monitoring

Abstract

The utility model provides a composite probe for cathode protection monitoring, which comprises a sheath, a reference electrode, a test piece and a cable, a mounting cavity is formed in the sheath, and a hole is formed in the side wall of the sheath; the reference electrode is mounted in the mounting cavity, and a protective layer is arranged outside the reference electrode; the test pieces are arranged on the side wall or the end part of the sheath, are made of the same material as a protected component, and comprise a direct current test piece and a natural test piece, the direct current test piece and the natural test piece are respectively provided with a non-working surface and a working surface, and each non-working surface is provided with an insulating layer and is used for preventing the non-working surface from being in contact with soil; a cable is mounted at the top of the sheath, and leads respectively connected with the reference electrode, the natural test piece and the direct-current test piece are arranged in the cable. The composite probe for cathode protection monitoring integrates the natural corrosion potential function and the direct current density function, and is compact in structure, convenient to install, good in conductivity, high in detection precision and long in service life.

Description

Technical Field

[0001] The utility model relates to a cathode protection device, in particular to a composite probe for cathode protection monitoring. Background Art

[0002] With the development of infrastructure projects, pipeline corrosion is an unavoidable problem in engineering, and cathodic protection has been widely used as an economical and effective method to prevent corrosion of buried or underwater metal components. Cathodic protection mainly includes impressed current cathodic protection and sacrificial anode protection. Sacrificial anode cathodic protection is to connect a metal with a more negative potential to the protected metal and place them in the same electrolyte, so that the electrons on the metal are transferred to the protected metal, so that the entire protected metal is at a relatively negative potential; impressed current cathodic protection is to add a large amount of electrons to the metal through an external DC power supply and an auxiliary anode, so that the protected metal is in a state of excess electrons as a whole, so that each point on the metal surface reaches the same negative potential, and the potential of the protected metal structure is lower than the surrounding environment.

[0003] For the cathodic protection system, the degree of cathodic protection is mainly monitored by measuring the polarization potential. The polarization potential parameter is an important indicator for monitoring and controlling the effect of cathodic protection. At present, the indicators for evaluating the effectiveness of cathodic protection at home and abroad all use polarization potential or polarization value (the offset value of polarization potential relative to natural corrosion potential). Therefore, accurate measurement of polarization potential and natural corrosion potential is of great significance to ensure the effective implementation of cathodic protection technology.

[0004] When the cathodic protection system is activated for buried pipelines, the IR drop caused by the cathodic protection current on the soil resistance causes errors in the online measurement of the pipe-to-ground potential, and it is difficult to measure the initial natural corrosion potential. In order to eliminate this part of the IR drop and measure the real polarization potential of the protected component, the instantaneous power-off method and the test piece power-off method are generally used. The instantaneous power-off method is a method that uses special equipment to instantly disconnect the cathodic protection current to measure the polarization potential of the pipeline; the instantaneous power-off method requires that all connected grounding protection, sacrificial anodes, and multiple cathodic protection devices on the protected component must be disconnected, and there should be no interference from stray currents at the test points; due to these requirements, the instantaneous power-off method is often difficult to implement in actual projects due to many inconveniences, such as the situation where there are multiple protection circuits, it is difficult to interrupt multiple power supply devices at the same time, and when there is stray current interference, even if the instantaneous power-off method is used, it is difficult to measure the real cathodic protection polarization potential.

[0005] There are problems with cathodic protection testing of buried pipeline metal components. With the construction of underground infrastructure, the interference of DC stray current on metal components is becoming increasingly prominent. As an important parameter for evaluating DC stray current corrosion, DC current density data collection is particularly important. Therefore, collecting accurate polarization potential and DC current density is an urgent problem to be solved in the cathodic protection system of foundation engineering. Utility Model Content

[0006] Technical issues to be solved

[0007] The technical problem to be solved by the utility model is to provide a composite probe for cathode protection monitoring which has the advantages of compact structure, convenient installation, accurate measurement and long service life.

[0008] Technical solutions to the problem

[0009] The utility model provides a composite probe for cathodic protection monitoring, which comprises:

[0010] A sheath, serving as a support and mounting carrier, wherein a mounting cavity is formed in the sheath, and a hole 10 is formed on the side wall of the sheath, which is connected to the mounting cavity and allows soil to enter;

[0011] A reference electrode 6 is installed in the installation cavity, and a protective layer is provided outside the reference electrode 6 to prevent the reference electrode 6 from directly contacting the soil;

[0012] A test piece 7, installed on the side wall or end of the sheath, and made of the same material as the protected component, includes a DC test piece and a natural test piece, both of which are provided with a non-working surface and a working surface capable of contacting the soil, and an insulating layer is provided on the non-working surface to prevent the non-working surface from contacting the soil;

[0013] The cable 5 is installed on the top of the sheath, and the cable is provided with wires connected to the reference electrode 6, the natural test piece and the DC test piece respectively.

[0014] Furthermore, the test specimen 7 is cylindrical, the bottom surface of the cylinder is the working surface, the side wall of the cylinder is the non-working surface, and the non-working surface is coated with a coating or an insulating sleeve 72 is fixed by epoxy resin.

[0015] Furthermore, the test strip is arranged at one end close to the reference electrode.

[0016] Furthermore, the reference electrode 6 is a prepackaged reference electrode.

[0017] Furthermore, a cotton bag is provided in the installation cavity, the cotton bag is filled with a filling material, and the reference electrode is arranged in the filling material.

[0018] Furthermore, the sheath includes a sleeve 1 with open ends, the holes 10 are multiple and are opened on the side wall of the sleeve 1, the upper open end of the sleeve 1 is provided with an upper cover body 2, the cable is fixed on the upper cover body 2, and the lower open end of the sleeve 1 is provided with a circular base 3, and the test specimen is installed on the bottom surface of the base 3.

[0019] Furthermore, a hole is formed on the inner wall of the lower open end of the sleeve 1 to accommodate the axial insertion of the base 3 , and the end of the base 3 contacts the end surface of the hole to achieve axial limitation.

[0020] Furthermore, the top of the base 3 forms a support portion and can contact and support the lower end of the reference electrode 6 .

[0021] Furthermore, a mounting hole 31 is provided on the upper end surface of the base 3, an axial hole is penetrated through the bottom surface of the mounting hole 31, a mounting column 71 is provided on the top of the test specimen 7, and the mounting column 71 passes through the axial hole from bottom to top and is connected to and fixed with a locking nut 73 in the mounting hole 31, and the wire is connected to the mounting column 71.

[0022] Furthermore, a concave hole 311 coaxial with the axial hole is formed on the bottom surface of the base 3 , and the top surface of the test piece contacts the bottom surface of the concave hole.

[0023] Beneficial Effects

[0024] The utility model discloses a composite probe for monitoring cathodic protection, which adopts a sheath structure to protect the electrode and the test piece, and adopts a hollow design to allow soil to enter and ensure operation, so the probe is stable in use and has a long service life; a pre-packaged reference electrode is adopted to avoid direct contact with the soil, and the installation is convenient and the service life is long; a double test piece structure is arranged, and has a working surface and a non-working surface, so the detection accuracy is high and the reliability of use is good; the reference electrode is close to the test piece, so the potential measurement error can be effectively avoided and the detection accuracy is improved; the utility model discloses a composite probe for monitoring cathodic protection, which integrates the functions of natural corrosion potential and DC current density, has a compact structure, is easy to install, has good conductivity, has high detection accuracy and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the composite probe for cathodic protection monitoring of the utility model;

[0026] Figure 2 This is a schematic diagram of the structure of the composite probe for cathodic protection monitoring of the utility model from another angle;

[0027] Figure 3 This is a schematic diagram of the internal structure of the composite probe for cathodic protection monitoring of the utility model;

[0028] Figure 4 This is a schematic diagram of the internal structure of the composite probe for cathodic protection monitoring of the utility model from another angle;

[0029] Figure 5 It is a schematic diagram of the installation of the test piece of the composite probe for cathodic protection monitoring of the utility model;

[0030] Figure 6 It is a cross-sectional view of the composite probe for cathodic protection monitoring of the utility model;

[0031] Figure 7 for Figure 6 Enlarged view of part A in the middle. DETAILED DESCRIPTION

[0032] The following is a detailed description of the embodiments of the present utility model in conjunction with the accompanying drawings.

[0033] See also Figure 1-Figure 7 The utility model provides a composite probe for cathodic protection monitoring, including a sheath, a reference electrode 6, a test piece 7 and a cable 5.

[0034] The sheath is used as a support and installation carrier. It is made of non-metallic material. In this embodiment, it is made of PVC and is used to install the reference electrode 6 and the test specimen 7. A mounting cavity is formed in the sheath. At the same time, a hole 10 is opened on the side wall of the sheath. The hole 10 is multiple and connected to the mounting cavity, which can allow soil to enter the mounting cavity; the reference electrode 6 is installed in the mounting cavity, and a protective layer is provided outside the reference electrode 6. The protective layer is used to prevent the reference electrode 6 from directly contacting the soil; the test specimen 7 is installed on the side wall or end of the sheath. The test specimen is made of the same material as the protected component. A working surface and a non-working surface are provided on the test specimen, wherein the working surface serves as a working end and can contact the soil, and an insulating layer is provided on the non-working surface. The insulating layer is used to prevent the non-working surface from contacting the soil; in this embodiment, the test specimen 7 includes a DC specimen and a natural The test piece, the natural test piece and the DC test piece have the same structure, and are installed at one end close to the reference electrode to avoid potential measurement errors and improve detection accuracy; the cable 5 is installed on the top of the sheath through a sealing joint 4, and the sealing joint includes a nut, a spring gasket and a gasket, which can achieve quick connection and improve the connection strength to avoid loosening or disintegration during construction. Three wires are arranged in the cable, specifically, including a first wire 51, a second wire 52 and a third wire 53, wherein the first wire 51 is connected to the reference electrode 6, the second wire 52 is connected to the DC test piece, and the third wire is connected to the natural test piece; the operation status of the cathodic protection of the protected component and the interference status of the stray current are accurately measured through the DC and natural test pieces; and the reference electrode is set at a relatively close distance to the test piece, which can effectively avoid potential measurement errors.

[0035] In the present embodiment, the reference electrode 6 is a prepackaged reference electrode. Specifically, a cotton bag is provided in the installation cavity, and the cotton bag is filled with a filling material, which is mainly composed of gypsum powder, sodium sulfate and bentonite. The reference electrode is arranged in the filling material, that is, the filling material covers the reference electrode as a whole, and the external filler and the cotton bag form a protective layer to prevent the reference electrode from direct contact with the soil, thereby protecting the reference electrode and extending its service life.

[0036] In the present application, the sheath includes a sleeve 1, an upper cover body 2 and a base 3. The sleeve 1 is cylindrical with open ends. A hole 10 is provided on the side wall of the sleeve 1. In the present embodiment, there are multiple holes (groups) and the holes are circumferentially provided on the side wall of the sleeve 1 to form a hollow structure, which can allow soil to enter the installation cavity from all sides; the upper cover body 2 is fixed to the open end of the upper end of the sleeve 1, and the cable is fixed on the upper cover body 2. The base 3 is annular and is installed on the open end of the lower end of the sleeve 1. Specifically, a hole body is provided on the inner wall of the open end of the lower end of the sleeve 1. The hole body is coaxial with the sleeve 1 to form a stepped hole structure. The seat 3 is just sleeved in the hole body, and the upper end portion (edge ​​portion) of the base 3 contacts the end face of the hole body, thereby realizing axial limitation, and the lower end face of the base 3 is flush with the bottom of the sleeve 1; the top of the base 3 forms a support portion, which can contact the lower end of the reference electrode 6 (pre-packaged) to achieve support for the reference electrode (pre-packaged); the reference electrode is in a pre-packaged form, that is, it includes a cotton bag and filler, therefore, it is placed in the installation cavity, and its overall outer diameter is larger than the inner hole diameter of the base 3 (annular), therefore, the lower end of the reference electrode contacts the base 3; the test specimen is installed on the bottom surface of the base 3.

[0037] Specifically, a mounting hole 31 is provided on the upper end surface of the base 3. The mounting holes are two and evenly distributed in the circumference, respectively used to install the DC test piece and the natural test piece. An axial hole is passed through the center of the bottom surface of the mounting hole 31, and a stepped hole structure with a large upper end and a small lower end is formed as a whole. The test piece 7 is cylindrical, and a mounting column 71 is provided on the top of the cylinder. The end of the mounting column 71 is provided with a thread. The mounting column 71 passes through the axial hole from bottom to top. At the same time, a locking nut 73 is provided in the mounting hole 31. The locking nut 73 is threadedly connected to the mounting column 71, thereby realizing the fixed installation of the mounting column 71. The wire is (electrically) connected to the mounting column 71, specifically, it is connected by welding; the bottom surface of the cylinder (test piece) is the working surface, and its area is determined according to the relevant It is required to design that the cylindrical (arc-shaped) side wall is a non-working surface, and an insulating layer is arranged on the non-working surface. The insulating layer can be a coating (insulating coating) coated on the side wall, or an insulating sleeve (tube) 72 fixed to the side wall by epoxy resin. It can also be understood that an insulating sleeve is arranged on the outer sleeve of the test specimen, and epoxy resin is filled between the insulating sleeve and the outer wall of the test specimen, thereby realizing sealed insulation treatment. The insulating sleeve can be a PVC tube to realize closed insulation of the non-working surface. In this embodiment, a recessed hole 311 is opened on the bottom surface of the base 3, and the recessed hole 311 is coaxial with the axial hole and connected, and the top surface of the test specimen is in contact with the bottom surface of the recessed hole, so as to improve the installation reliability of the test specimen. Preferably, the side wall of the recessed hole 311 is a slope.

[0038] The utility model discloses a composite probe for monitoring cathodic protection, which adopts a sheath structure to protect the electrode and the test piece, and adopts a hollow design to allow soil to enter and ensure operation, so the probe is stable in use and has a long service life; a pre-packaged reference electrode is adopted to avoid direct contact with the soil, and the installation is convenient and the service life is long; a double test piece structure is arranged, and has a working surface and a non-working surface, so the detection accuracy is high and the reliability of use is good; the reference electrode is close to the test piece, so the potential measurement error can be effectively avoided and the detection accuracy is improved; the utility model discloses a composite probe for monitoring cathodic protection, which integrates the functions of natural corrosion potential and DC current density, has a compact structure, is easy to install, has good conductivity, has high detection accuracy and a long service life.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A composite probe for cathodic protection monitoring, characterized in that: include: A sheath, serving as a support and mounting carrier, wherein a mounting cavity is formed in the sheath, and a hole is formed on the side wall of the sheath to communicate with the mounting cavity and allow soil to enter; A reference electrode is installed in the installation cavity, and a protective layer is provided outside the reference electrode to prevent the reference electrode from directly contacting the soil; A test piece, installed on the side wall or end of the sheath, and made of the same material as the protected component, including a DC test piece and a natural test piece, both of which are provided with a non-working surface and a working surface capable of contacting the soil, and an insulating layer is provided on the non-working surface to prevent the non-working surface from contacting the soil; A cable is installed on the top of the sheath, and the cable is provided with wires connected to the reference electrode, the natural test piece and the DC test piece respectively.

2. The composite probe for cathodic protection monitoring according to claim 1, characterized in that: The test specimen is cylindrical, the bottom surface of the cylinder is a working surface, the side wall of the cylinder is a non-working surface, and the non-working surface is coated with a coating or fixed with an insulating sleeve by epoxy resin.

3. The composite probe for cathodic protection monitoring according to claim 1, characterized in that: The sheath is made of non-metallic material.

4. The composite probe for cathodic protection monitoring according to claim 1, characterized in that: The reference electrode is a prepackaged reference electrode.

5. The composite probe for cathodic protection monitoring according to claim 1 or 4, characterized in that: A cotton bag is arranged in the installation cavity, the cotton bag is filled with a packing material, and the reference electrode is arranged in the packing material.

6. The composite probe for cathodic protection monitoring according to claim 1, characterized in that: The sheath comprises a sleeve with open ends, the holes are multiple and are opened on the side wall of the sleeve, the upper open end of the sleeve is provided with an upper cover body, the cable is fixed on the upper cover body, the lower open end of the sleeve is provided with a circular base, and the test specimen is installed on the bottom surface of the base.

7. The composite probe for cathodic protection monitoring according to claim 6, characterized in that: The inner wall of the lower open end of the sleeve is provided with a hole body for accommodating the axial insertion of the base, and the end of the base contacts the end surface of the hole body to achieve axial limitation.

8. The composite probe for cathodic protection monitoring according to claim 6, characterized in that: The top of the base forms a supporting portion and can contact and support the lower end of the reference electrode.

9. The composite probe for cathodic protection monitoring according to claim 6, characterized in that: A mounting hole is provided on the upper end surface of the base, an axial hole passes through the bottom surface of the mounting hole, a mounting column is provided on the top of the test specimen, and the mounting column passes through the axial hole from bottom to top and is connected to and fixed with a locking nut in the mounting hole, and the wire is connected to the mounting column.

10. The composite probe for cathodic protection monitoring according to claim 9, characterized in that: The bottom surface of the base is provided with a concave hole coaxial with the axial hole, and the top surface of the test piece contacts the bottom surface of the concave hole.

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