RU89116U1 - ELECTRODE FOR CATHODE PROTECTION (OPTIONS) AND DEVICE FOR CATHODE PROTECTION OF INTERNAL SURFACES OF METAL AND / OR REINFORCED CONCRETE PRODUCTS OR STRUCTURES - Google Patents

Abstract

1. An electrode for the cathodic protection of the internal surfaces of metal and reinforced concrete products or structures, including a sparingly soluble anode of electrically conductive material, mounted in a perforated insulating sheath and electrically connected to a current lead configured to connect to one of the poles of the cathodic protection station, characterized in that the perforated the insulating shell is made in the form of fragments of measured length with elasticity less than the total elasticity of the sparingly soluble anode and then coprovoda and placed on the anode with the possibility of free movement along it. ! 2. The electrode of claim 1, characterized in that as an electrically conductive poorly soluble material of the anode, an elastomeric mixture is used, at least on the basis of synthetic butadiene-nitrile rubber, or chloroprene, or ethylene-propylene diene, or a mixture thereof having a range of volumetric electrical resistivity 0.5-2500 Ohm.m ! 3. The electrode according to claim 1, characterized in that a copper multi-wire core is used as a current lead. ! 4. The electrode according to claim 1, characterized in that the perforations in the insulating shell are made in the form of holes or grooves, the total area of which is not less than 50% of the working area of the anode. ! 5. An electrode for cathodic protection of the inner surfaces of metal and reinforced concrete products or structures, including a sparingly soluble anode of electrically conductive material, provided with an insulating sheath and electrically connected to a current lead configured to connect to one of the poles of the cathodic protection station, characterized in that

Description

Utility models relate to the field of protection of metal objects from corrosion and can be used in various sectors of economic activity to effectively protect the internal surfaces of metal and / or reinforced concrete products or structures from electrochemical corrosion.

Known electrode for cathodic protection against corrosion of the inner surface of the reservoirs of the oil and gas industry, which is part of a corresponding device containing a source of protective current and an anode in a perforated dielectric screen, which is closed, and perforation holes of the screen are placed above the anode location zone [Description of the invention to the USSR copyright certificate No. 1271141 dated 02.20.1985, IPC ⁶ C23F 13/02, published 02/10/1996]. The special design of the anode (electrode) provides increased explosion safety of the device.

The disadvantage of this electrode, as well as the device based on it, is its specialization, since it can be used with high efficiency only to protect against corrosion of tanks, and when used on long pipelines or broken structures, it is not applicable, because it does not have the necessary for this spatial flexibility.

Known electrode for cathodic protection against corrosion of the inner surface of the tank, which is part of a corresponding device containing a source of protective current, the positive pole of which is connected to the anode placed in a closed perforated dielectric screen, which ends at the opposite hatches of the tank, with holes of the dielectric screen placed above of the anode location zone and above them a protective screen is installed, while the negative pole of the protective current source is connected to reservoir of, and the anode is integrally tokoprovodnika on which are arranged evenly along the contact connections, each of which is connected to the positive pole of the protection current [Disclosure of the invention to the patent of Russian Federation №2183696 17.03.2000, MPK7 C23F 13/02, publ. 06/20/2002].

An improved variant of the above invention is a device and, accordingly, an electrode for cathodic protection, the dielectric and protective shields of which are installed at an angle to the horizon [Description of the invention to RF patent No. 2280711 of 12/27/2004, IPC C23F 13/06, publ. July 27, 2006].

Both inventions provide an increase in the efficiency of protecting tanks against corrosion, an increase in the degree of explosion safety, a decrease in the laboriousness when replacing the electrodes in the anode, the most complete collection and removal of gases emitted during the operation of the electrode outside the tank, an increase in the utilization of electrodes when using non-specialized, slightly soluble electrodes by improving the design features of the anode.

These solutions have the same drawbacks as the decision on USSR copyright certificate No. 1271141 - they cannot be applied, for example, on long sections of pipelines and broken structures.

A technical solution is known for the cathodic protection of the inner surface of pipelines against corrosion [Description of the invention to the patent of the Russian Federation No. 1713978 from 09/13/1989, IPC ⁵ C23F 13/00, publ. 02/23/1992]. Poorly soluble anodes are placed in the pipeline with a certain step, connected to an extended current lead, a channel with one or two open ends with a dielectric wall is formed around each anode, communicating at the ends with the environment, and the anodes are offset relative to the channel's communication with the medium. As a result, the uniformity of the drainage of the protective current from the anodes along the length of the pipeline is increased, which allows avoiding "overload" or "underprotection" of individual sections of the pipeline.

The disadvantage of this device is that the electrode, as a working element of cathodic protection, is a set of many separate structures of the same type, containing many contact nodes, which are the most unreliable element of the device, and the wear of individual electrodes is uneven. Thus, a contradiction arises between satisfactory protection of the inner surface of pipelines against corrosion and the need for costly electrode replacement in conditions where only one of the anodes of the electric circuit undergoes more intense wear.

Closest to the set of essential features, the claimed technical solutions of electrodes for cathodic protection of the internal surfaces of various products or structures is a cathodic protection device for the inner surface of pipelines, including a sparingly soluble anode installed in a perforated insulating sheath and electrically connected to an extended current lead connected to the cathodic protection station, this, as an anode using an electrically conductive polymer material deposited over ny conductive and insulating shell is provided with protection rings [Description of a utility model patent for RF №2816 from 08.08.1994, MPK6 C23F 13/08, publ. September 16, 1996]. The anode has the necessary flexibility for bending and can be used even on bent pipe sections. Thus, the device provides effective protection against corrosion of the inner surface of the pipelines and reduce capital and operating costs.

The disadvantages of this technical solution include the fact that the mechanical protection of the anode is carried out only when it is dragged inside the pipe. It is known that the working medium inside the pipeline has certain physical characteristics, such as, for example, density, speed and flow regime, and others, i.e. there is a noticeable mechanical impact on the electrode, leading to its erosion in local areas, to the uneven distribution of the protection current, etc. This significantly reduces the standard life of the electrode and, accordingly, the pipeline, and leads to significant capital costs for its repair and restoration of cathodic protection.

The problem to be solved by the first and second useful model of the group and the technical result achieved are to create elastomeric electrodes for the cathodic protection of the internal surfaces of metal and reinforced concrete products or structures, which are distinguished by an extended scope of application in terms of resistance to aggressive environments and mechanical stresses, a wide range of self-resistance, providing uniform distribution of protective current, low coefficient of anodic dissolution, ease of execution and reliability spine operation.

To solve the problem and achieve the claimed technical result in the design of the first electrode for the cathodic protection of the inner surfaces of metal and reinforced concrete products or structures, including a sparingly soluble anode of electrically conductive material, mounted in a perforated insulating sheath and electrically connected to the current lead, configured to connect to one of poles of the cathodic protection station, the perforated insulation shell is made in the form of fragments of a measured lengths with elasticity less than the total elasticity of the sparingly soluble anode and current lead and is placed on the anode with the possibility of free movement along it.

Besides:

- as an electrically conductive poorly soluble material of the anode, an elastomeric mixture is used, at least on the basis of synthetic butadiene-nitrile rubber, or chloroprene, or ethylene-propylene diene, or a mixture thereof, having a specific electric resistance range of 0.5-2500 Ohm · m;

- a copper multi-wire core is used as a current lead;

- perforations in the insulating shell are made in the form of holes or grooves, the total area of which is not less than 50% of the working area of the anode.

In the design of the second electrode for cathodic protection of the inner surfaces of metal and reinforced concrete products or structures, including a sparingly soluble anode of electrically conductive material, provided with an insulating sheath and electrically connected to a current lead configured to connect to one of the poles of the cathodic protection station, the insulating sheath is made in the form at least one spiral cord or insulating solid cord arranged on a spiral surface of the anode, preferably of circular cross-section, and disposed along the length of the anode top is uniformly distributed circumferentially additional insulating tows, or filaments, wherein the insulating harnesses or cables are fixed to the outer surface of the anode, at least, with a pitch equal to or a multiple step helical winding of insulating harness.

Besides:

- insulating harnesses or cords are made with total elasticity greater than the total elasticity of the sparingly soluble anode and conductor;

- as an electrically conductive poorly soluble material of the anode, an elastomeric mixture is used, at least on the basis of synthetic butadiene-nitrile or chloroprene or ethylene-propylene diene rubber, or a mixture thereof having a specific electric resistance range of 0.5-2500 Ohm · m;

- a copper multi-wire core is used as a current lead;

- insulating harnesses or cords are fixed to the outer surface of the anode using fixing dielectric rings having wear resistance superior to the wear resistance of harnesses or cords;

- dielectric rubber is used as the material of the insulating tourniquet or insulating solid cord.

The above information from the prior art is applicable to the third utility model of the group - the cathodic protection device of the inner surfaces of metal and reinforced concrete products or structures. A typical cathodic protection device contains a direct current source connected by a negative pole to the product or structure, and positive through the input device to the anode, electrically isolated from the product or structure and made in the form of a single electric current conductor.

The problem to be solved by the third useful model of the group and the technical result achieved is to create a cathodic protection device for the internal surfaces of metal and reinforced concrete products or structures equipped with appropriate electrodes, which are distinguished by an extended scope of application for resistance to aggressive environments and mechanical stresses, a wide range of self-resistance, providing uniform distribution of protective current, low coefficient of anodic dissolution, simplicity Design Nominal and reliability in operation.

To solve the problem and achieve the claimed technical result in the cathodic protection device of the inner surfaces of metal and reinforced concrete products or structures containing a direct current source connected by a negative pole to the product or structure, and positive through the input device to the anode electrically isolated from the product or structure and made in the form of a single electric current conductor, the electric current conductor is made in the form of an electrode according to any one of the following above technical solutions. Additionally, the input device includes a tubular body with a seat for a seal and a threaded section for a threaded sleeve, and the seat includes a thrust step, while the seal is made in the form of a set of at least one thrust washer and at least one elastic element made with the possibility of interaction with the end face of the threaded sleeve and the stop step.

Utility models are illustrated by drawings, where:

- figure 1 shows a General view of the first variant of the electrode for cathodic protection of the internal surfaces of metal and reinforced concrete products or structures - execution with perforations in the insulating shell made in the form of holes - axonometric projection;

- figure 2 also shows a General view of the first variant of the electrode - execution with perforations in the insulating shell, made in the form of grooves - axonometric projection;

- figure 3 shows an arbitrary cross-section of the electrode of figure 1 or figure 2 with arbitrary perforations;

- figure 4 shows a General view of a second variant of the electrode for cathodic protection;

- figure 5 shows an arbitrary cross-section of the electrode of figure 4;

- figure 6 shows a scan of the insulating shell of the electrode of figure 4;

- Fig.7 shows one of the possible designs of the fixing dielectric ring of Fig.4 - a fragment of the scan in axonometric projection;

- Fig. 8 shows a device for introducing an electrode of Fig. 1 or Fig. 2, or Fig. 4 (conventionally shown) into a protected product or structure.

In the General case, the electrode 1 for the cathodic protection of the inner surfaces 2 of metal and reinforced concrete products or structures 3 includes a sparingly soluble anode 4 of an electrically conductive material mounted in a perforated insulating sheath 5 and electrically connected to a conductive 6 configured to connect to one of the poles of the cathodic protection station (conditionally not shown). As an electrically conductive poorly soluble material of the anode 4, an elastomeric mixture is used, at least based on synthetic butadiene-nitrile rubber, or chloroprene, or ethylene propylene diene, or a mixture thereof, having a specific electric resistance range of 0.5-2500 Ohm · m, and as conductor 6 use a copper multi-wire core.

In the first embodiment of the electrode 1, the perforated insulating sheath 5 is made in the form of fragments of measured length with elasticity less than the total elasticity of the sparingly soluble anode 4 and current lead 6 and is placed on the anode 4 with free movement along it, and the perforations in the insulating sheath 5 are made in the form of holes 7 or grooves 8, the total area of which is not less than 50% of the working area of the anode 4.

In the second embodiment of the electrode 1, the insulating sheath 5 is made in the form of at least one, located on the surface of the anode 4 in a spiral insulating harness or insulating solid cord 9, mainly of circular cross section, and located on top along the length of the anode 4 additionally insulating uniformly distributed around the circumference harnesses or cords 10, while the insulating harnesses or cords 9 and 10 are fixed on the outer surface of the anode 4, at least with a step t equal to or a multiple of step t _{1 of} winding the spiral insulating harness 9. And insulating harnesses or insulating solid cords 9 and 10 are made with total elasticity greater than the total elasticity of the sparingly soluble anode 4 and conductor 6, and dielectric rubber is used as the material of the insulating harnesses or cords 9 and 10, while the harnesses and cords 9 and 10 are fixed to the outer surface of the anode 4 by means of fixing dielectric rings 11 having wear resistance superior to the wear resistance of bundles and cords 9 and 10.

The cathodic protection device of the inner surfaces 2 of metal and reinforced concrete products or structures 3 traditionally contains a direct current source (not shown conventionally) connected by a negative pole to the product or structure 3, and positive through an input device 12 to the anode 4, electrically isolated from the product or structure 3 and made in the form of a single electric current conductor, while the electric current conductor is made in the form of an electrode 1 according to any of the above options, and the input device 12 covers a tubular body 13 with a seat 14 for a seal and a threaded section 15 for a threaded sleeve 16, and the seat 14 includes a stop step 17, the seal being made in the form of a set of at least one elastic element 18 and at least , one thrust washer 19, made with the possibility of simultaneous interaction with the end face 20 of the threaded sleeve 16 and the thrust step 17.

Let us analyze the materiality of features of utility models and the possibility of implementing technical solutions.

The implementation of the perforated insulating shell 5 according to the first embodiment of the utility model — in the form of fragments of measured length (see FIGS. 1 and 2) placed on the anode 4 with the possibility of free movement along it, provides the necessary flexibility of the assembled electrode 1, making it possible to repeat any form of spatial geometry of the inner surface 2 of the protected product or structure 3 and at the same time maintain the increased strength characteristics of the shell 5, providing protection from almost any possible unauthorized mechanical effects.

The parameter ensuring the operability of such a structure is the ratio of the total elasticity of the sparingly soluble anode 4 and the current lead 6 and the perforated insulating sheath 5. When encircling the inner surfaces of 2 steeply curved sections of the protected products and structures 3, fragments of the insulating sheath make the anode 4 bend smoother, which avoids its kink , for example, at low operating temperatures. In addition, less elasticity implies increased strength characteristics of the parts. When pulling a low-elastic anode 4 inside, for example, a bent pipe, there is a high probability of "collecting" fragments of the insulating shell 5 if it will have greater elasticity than the elasticity of the anode 4.

It should be noted that the necessary condition for the poorly soluble anode 4 to perform its function is the total perforation area — periodically located holes 7 or grooves 8 — that is at least 50% of the working area of the anode 4. Otherwise, an anode and an accelerated consumption (wear) of the anode will be observed 4 - what will inform about the presence of undissolved anode 4 over the "closed" sections of the insulating shell and, conversely, premature exposure of the conductor 6.

Similarly to the first embodiment, the implementation of the insulating shell of the second embodiment of the electrode 1 (see Fig. 4) in the form of a circular insulating cord or insulating solid cord 9 of circular cross section placed on the surface of the anode 4, and located on top along the length of the anode 4 are additionally insulating evenly distributed around the circumference bundles or cords 10 allows you to create an "active" design of the electrode 1 for cathodic protection, which can also be used not only in the straight sections of the protected products or structures 3, but also on curved. When dragging such an electrode 1 inside long straight or conditionally straight pipes, it does not matter what the elasticity of the insulating ropes or cords 9 and 10 is - it requires resistance to mechanical stresses arising during installation and from periodic mechanical stresses of the working medium during operation, however, on bent the sections require sufficient flexibility and extensibility of the bundles or cords 9 and 10, which will allow the anode 4 to freely reproduce the spatial geometry of the internal 2 erhnosti protected articles or structures 3. For this reason, the insulating strands and cords 9 and 10 are made with the total elasticity greater overall elasticity sparingly anode current distributor 4 and 6.

It is recommended to use dielectric rubber based on butadiene-nitrile, chloroprene or ethylene-propylene rubbers, which has stable, predictable, and required properties as the material of insulating ropes or insulating solid cords 9 and 10.

The fastening of insulating ropes or cords 9 and 10 on the outer surface of the anode 4 with a step t equal to or a multiple of t _{1 of the} winding of a spiral insulating bundle or an insulating solid cord 9 provides predictability of the physical characteristics of electrode 1 and the manufacturability of its manufacture using various means of mechanization. Such fastening of the bundles or cords 9 and 10 by means of fixing dielectric rings 11 with special grooves 21 on their inner surface, which have wear resistance superior to the wear resistance of the bundles or cords 9 and 10, allows the electrode 1 to be dragged inside, for example, concrete water conduits known for their highly abrasive properties surfaces without a visible violation of the mechanical integrity of the insulating sheath 5. For ease of assembly, the dielectric rings 11 may, for example, be detachable. Their fixation on the anode 4 can be carried out, for example, using standard clamps 22.

Otherwise, in the design of both versions of the electrode 1, an elastomeric mixture, at least based on synthetic butadiene-nitrile rubber, or chloroprene, or ethylene-propylene diene, or a mixture thereof, is used as an electrically conductive poorly soluble material of the anode 4. Today, these are the most suitable polymer compositions in terms of physicochemical characteristics and are suitable for the manufacture of sparingly soluble anodes (see, for example, the description of the invention to RF patent No. 2225420 of June 19, 2003, IPC ⁷ C08L 9/02, C08L 9/06, C08L 11 / 00, C23F 13/00, C23F 13/16, published March 10, 2004; application No. 2008139201 dated October 2, 2008, IPC C08L 9/00, Н01В 1/00 for the invention “Rubber compound and electric current conductor”, etc. ) The main feature of these elastomers is their pronounced resistance to aggressive environments, which allows them to be used on almost any national economic objects. This allows you to ensure the life of the cathodic protection in accordance with the requirements of GOST 9.602-2005 and GOST R 51164-98 - at least 15 years.

The proposed range of volumetric electrical resistivity of elastomeric mixtures in the range from 0.5 to 2500 Ohm · m ensures uniform distribution of the protective potential on the inner surface of 2 metal and reinforced concrete products or structures 3 and a sharp increase in protection efficiency. This is achieved by introducing into the composition of elastomeric mixtures compositions of carbon materials (carbon black - carbon black, various modifications of graphite, etc.) in a certain mass ratio.

The choice of the value of the specific volumetric electrical resistance of the elastomeric material of the anode 4 is determined by the specific electrical characteristics (longitudinal, transitional electrical resistance, insulation resistance) of the object of protection, the characteristics of the transported product, the size and configuration of the object, etc. The following source of information can be recommended as a universal publication that allows making all the necessary calculations of the electrochemical protection of the inner surfaces of 2 metal and reinforced concrete products or structures 3: Sinko V.F. Integrated electrochemical protection against corrosion of structures and equipment in soils and liquid media. Monograph. Kolomna: FGOU KIPP. 2009.292 s.

The use of a copper multi-wire core as a current lead 6 ensures the flow of electric current over the increased (from station to station) length of the anode 4 and its necessary flexibility and strength. A case is possible when the electrode 1 can be fixed on the product or structure 3 with just one point with the placement, for example, downstream of the liquid flow, and, accordingly, the supply of the positive potential will also be carried out to the current lead 6 at just one point.

As for the design of the cathodic protection devices of the inner surfaces 2 of metal and reinforced concrete products or structures 3, their feature is the special design of the options for electrode 1 - a single conductor of electric current, which allows to expand the scope of cathodic protection and extend it to such products or structures, such as, for example , oil and gas field networks and equipment, equipment and engineering networks of oil refineries and oil storage facilities, urban utilities networks water supply and sewerage, oil-producing platforms, concrete water conduits, including extended versions, etc. This ensures uniform distribution of the protective potential, low dissolution of the anodes 4, and, therefore, a higher efficiency of the corrosion protection system.

The most problematic part of the cathodic protection device is the input device 12 of electrode 1. Its universal design has been developed, which ensures the manufacturability of connecting various products or structures 3 to the housings, the convenience and simplicity of mounting and dismounting, and the necessary sealing of the obtained compounds. Despite the possible relief profile of the surface of the anode 4, deformable elastic elements 18 provide reliable sealing of the connection. In addition, this design of the input 12 is applicable, if necessary, and for supplying an intermediate conductor from the positive pole of the DC source (not shown conventionally). In the prior art there is no information about the application of such a design of the input device 12 for protected from corrosion products.

In the rest, the implementation of utility models is carried out by traditional, long-established methods widely represented in patent and technical literature.

As a result of the solution of the set tasks, electrode versions were created for the cathodic protection of the internal surfaces of metal and reinforced concrete products or structures and a cathodic protection device based on them, characterized by an expanded field of application for resistance to aggressive environments and mechanical stresses, a wide range of intrinsic resistance, ensuring uniform distribution of protective current, low coefficient of anodic dissolution, ease of execution and reliability in operation.

Claims (12)

1. An electrode for the cathodic protection of the internal surfaces of metal and reinforced concrete products or structures, including a sparingly soluble anode of electrically conductive material, mounted in a perforated insulating sheath and electrically connected to a current lead configured to connect to one of the poles of the cathodic protection station, characterized in that the perforated the insulating shell is made in the form of fragments of measured length with elasticity less than the total elasticity of the sparingly soluble anode and then coprovoda and placed on the anode with the possibility of free movement along it. 2. The electrode of claim 1, characterized in that as an electrically conductive poorly soluble material of the anode, an elastomeric mixture is used, at least on the basis of synthetic butadiene-nitrile rubber, or chloroprene, or ethylene-propylene diene, or a mixture thereof having a range of volumetric electrical resistivity 0.5-2500 Ohm.m 3. The electrode according to claim 1, characterized in that a copper multi-wire core is used as a current lead. 4. The electrode according to claim 1, characterized in that the perforations in the insulating shell are made in the form of holes or grooves, the total area of which is not less than 50% of the working area of the anode. 5. An electrode for the cathodic protection of the internal surfaces of metal and reinforced concrete products or structures, including a sparingly soluble anode of electrically conductive material, provided with an insulating sheath and electrically connected to a current lead configured to connect to one of the poles of the cathodic protection station, characterized in that the insulating sheath is made in the form of at least one, placed on the surface of the anode in a spiral insulating harness or insulating solid cord, mainly of circular cross-section, and disposed along the length of the anode top is uniformly distributed circumferentially additional insulating tows, or filaments, wherein the insulating harnesses or cables are fixed to the outer surface of the anode, at least, with a pitch equal to or a multiple step helical winding of insulating harness. 6. The electrode of claim 5, characterized in that the insulating ropes or cords are made with total elasticity greater than the total elasticity of the sparingly soluble anode and conductor. 7. The electrode of claim 5, characterized in that as an electrically conductive poorly soluble material of the anode, an elastomeric mixture is used, at least on the basis of synthetic butadiene-nitrile or chloroprene, or ethylene-propylene diene rubber, or a mixture thereof having a specific volume resistivity range of 0 5-2500 Ohm.m 8. The electrode according to claim 5, characterized in that a copper multi-wire core is used as a current lead. 9. The electrode according to claim 5, characterized in that the insulating harnesses or cords are fixed to the outer surface of the anode using fixing dielectric rings having wear resistance superior to the wear resistance of the harnesses or cords. 10. The electrode according to claim 5, characterized in that the dielectric rubber is used as the material of the insulating bundle or insulating solid cord. 11. A cathodic protection device for the inner surfaces of metal and reinforced concrete products or structures, containing a direct current source connected by a negative pole to the product or structure, and positive through an input device to the anode electrically isolated from the product or structure and made in the form of a single electric current conductor characterized in that the electric current conductor is made in the form of an electrode according to any one of claims 1 to 4 or 5-10. 12. The device according to claim 11, characterized in that the input device includes a tubular body with a seat for a seal and a threaded section for a threaded sleeve, and the seat includes a thrust step, while the seal is made in the form of a set of at least one thrust washer and at least one elastic element, made with the possibility of interaction with the end of the threaded sleeve and thrust step.