RU1040836C - Apparatus for electrochemical protection extended underground construction from corrosion - Google Patents

Description

The invention relates to the field of corrosion protection, in particular to devices for electrochemical protection of pipelines. A device is known for electrochemical corrosion protection of long underground structures, for example pipelines, containing a direct current source, the negative pole of which is connected to the protected structure, anode grounding, electrically connected to the positive pole of the mentioned source and an additional cathode (or screen) grounding, located between the building and the inland anode; grounding and electrically connected to the structure at the point of connection to the last of the negative pole (cathode) UPO; m NUTR1O for one source; all the time. ; This device provides protection for: however, protection (due to the introduction of up to a complete e-fuse) is earthed and, 4To: crv6cp6cTBiyeT reduce unnecessary potential difference between the pipeline And: the environment in the point of connection of a constant source of source ..; The disadvantage of the known device in /. is that it requires additional ;; the cost of the shielding of the earth screen. ,,:;. ;; -;, -: / ./ Y ... i (,; A well-known device for electrochemical corrosion protection of extended D) earth containing AC source, the middle and extreme points of which are connected through the valve elements / are connected to the electrodes to be protected. The conductor and the anode are grounded, respectively, when they are polarized, they are stably negative and positive in the same way; discretely placed in the environment near the structure so that it can be electrically identified with a linear electrode, and on the protected structure there is only one point, current collector from the current source ..; This device provides the creation of an electric field of protection current, providing a cyclically exponentially more uniform distribution of the protective potential difference along the structure. The device is the closest to the proposed technical essence and the achieved result. However, optimization of the operating protection parameters according to the known device requires a double adjustment of the protection current in each discrete element of the anode gap: in communication. with a temporary change in the electrical parameters of the sections of the protected structure and in connection with a change in the spreading resistance of the discrete anode ground elements when they are triggered. This complicates the system, which reduces its reliability. In addition, the superimposed potential of the structure at the current collection point, which is directly proportional to the total current of the source protection, is unreasonably large, which reduces the protection efficiency and reduces the length of the protection zone. The purpose of this invention is to increase the efficiency of the ison of protection while increasing the reliability of the device by making anode grounding in the form of a point electrode. . v The goal is achieved by the fact that in the device for electrochemical corrosion protection of an extended underground structure containing an alternating current source connected to conductors and with a protected structure and: anode ground, the anode ground is connected by the midpoint of the current source, and the points of the pickup are distributed discretely along the protective structure of each structure, and each is connected to the extreme points of the current source by means of two parallel chains including a variable resistor and a valve element, and valve are elements that are connected to the same point of the current collector, cathode connected to said source of extreme points in; prtivofaze,: In order to increase the regulated range. At least two separate insulating inserts shunted by the regulation resistance may be connected between every two adjacent points of current survey at the protected structure. In FIG. 1.2 shows two variants of the circuit design of the device and the distribution diagram of the protective potential distribution. The device contains an alternating current source, for example, a transformer 1. The midpoint 2 of the transformer 1 is connected by electrical conductors 3 to the anode ground 4. The extreme points 5. and 6 of the transformer 1 are connected by electrical conductors each through the control resistance 7 and valve element 8 to the points 9 current collector, spaced along the protected structure 10. In this case, the valve elements 8 connected to the point 9 of the current collector are connected to the extreme points 5 and 6 of the source in antiphase. Similarly, the other extreme points of the transformer 1 are connected to the corresponding current collection point. An insulating insert 11 (for example, a flange) is connected between adjacent points of the current collection point in the structure 10, which is shunted by the regulating resistance 12. Similar inserts can be connected between each pair of adjacent current collection points in the event of the presence of three or more torques. The device operates as follows ... .. An alternating current source, for example, transformer 1, is connected to the mains and the building - medium-anode grounding system begins to circulate a protective-: outlet. In this case, a positive electric field appears on the anode ground 4, which is constant, since the circuit closure of the anodic ground medium occurs from the midpoint 2 of the transformer 1. When the current direction of the network is cycled, parallel circuits alternately operate connecting the extreme points 5 and 6 of the transformer 1 Each of the current collector jars 9 and the protected structure, for example, pipeline 10. Moreover, in each pair of the indicated parallel circuits connected to the same current collector point, alternately opposite ofaze are opened ventilg nye elements 8, resulting in a current collector 9 is imposed a constant cathode field. -. . . An electric current flowing from the anode ground 4 flows along the pipeline 10, shifting the potential of the medium around it in a positive direction. In this case, the uniform distribution of the potentials of the medium (soil) increases due to the power of the collector points discretely distributed at the structure, in which the protective current is collected to return to the current source ... The potential of the cathodic field of the structure increases as it approaches the collector point, reaching maximum value at this point ..: The indicated potential distribution of the pipeline and soil provides increased protection efficiency by increasing the uniformity of the distribution of the potential difference of the pipeline-soil. In this case, the uniformity of the distribution of the potential difference increases with the separation of the anode grounding and current collection points, since in areas of the construction-environment system where the absolute value of the negative potentials of the pipeline decreases. The value of the positive potentials of the soil increases, and vice versa. For this, the anode ground 4 is placed at such a distance from the pipeline 10. that its anode electric field biases the ground potential around the pipeline in a positive direction. The distance between adjacent current collection points should be such that the gradient of the potential of the structure is compensated by the gradient of the potential of the medium (soil). Electrical characteristics (longitudinal and transitional resistance) of individual sections of the pipeline vary along its length, which usually leads to a decrease in the uniformity of the distribution of the protective potential difference. In the proposed system, equalization of the protective potential difference is carried out by sectioning the pipeline in the indicated sections by sequentially connecting insulating inserts 11, for example flanges, shunted by each regulating resistance 12. The shunted inserts 11 compensate for the differentiation of the input resistance of the pipeline. Additional equalization of the protective potential difference is also carried out through adjusting resistances 7, connecting the extreme points of the current source with the points of current collection at the building. Additional equalization of potentials contributes to an additional increase in protection efficiency. The device can also be used to protect cables. Since the proposed device has one powerful metal-intensive grounding; a change in its parameters during operation (ectrds does not affect significantly the distance along the protected structure and the reliable operation of the system is adjusted only to compensate for changes in the electrical characteristics of individual sections of the pipeline or cable, if there is high voltage at the output of transformer 1 that is dangerous to human life, a standard automatic protection system (not shown) is included in the power circuit, which turns off the power when the protective current is reduced The proposed device allows to reduce the number of cathodic protection installations by 3-4 times in comparison with the cathodic protection system used on the CPTO-Center gas pipeline, which is the basic object. protection by 20-30%, and the length of the protective zone is increased by 3-4 times.

The economic effect of the implementation of the proposed device is approximately 2140 rubles / km per year,

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tp o rmula and 3

1. DEVICE FOR ELECTRONIC TROCHEMICAL PROTECTION AGAINST CORROSION OF AN EXTENDED UNDERGROUND STRUCTURE, containing an alternating current source connected by conductors to the protected structure and anode grounding, distinguished by the fact that, in order to increase the efficiency and protection zone while improving the reliability: a point electrode electrode anode ground is connected to the midpoint of the current source and the current collection point; distributed discreetly YODOL shielding (56) Copyright certificate of the USSR Ne 250978, cl. C 23 F 13/00. 1965.

USSR author's certificate N 790847, cl. C 23 F 13/00. 1979.

At the same time, each structure is connected to the extreme points of the current source by means of two parallel circuits, including n6 variable resistor and the valve element, the valve elements connected to the same current collector point being connected by cathodes to the said extreme points of the source in antiphase. 2.; - The device according to claim 1, characterized in that at least one insulating insert shunted by the regulation resistance is connected between each two adjacent current collection points on the protected structure.

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