RU2484448C1 - Method and device to realise contact of electrochemical protection parameters monitoring unit with pipe with applied weighting concrete coating - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method includes creation of tight contact of a unit of electrochemical protection parameters monitoring with a pipe having a weighting concrete coating. The device for realisation of the method creates a tight contact with application of a capsule that expands when exposed. The electrochemical protection parameters monitoring unit within the device for contact realisation comprises a weighting agent, where two comparison electrodes are installed with potential sensors and two indicators of corrosion speed. In a particular case the electrochemical protection parameters monitoring unit may be arranged in a layer of the weighting coating and have a screen for display of electrochemical protection parameters.

EFFECT: improved accuracy of pipe steel corrosion characteristics detection, assessment of pipe protection against corrosion and efficiency of electrochemical protection at the same time.

6 cl, 9 dwg

Description

The invention relates to a system for monitoring corrosion processes in steel underground and underwater structures located under a layer of concrete, to determine the danger of steel corrosion and control the effectiveness of electrochemical protection.

Closest to this technical solution is the "method of monitoring the state of the reinforcement of the underground part of the reinforced concrete supports of the contact network" (see RF patent No. 2323220, IPC G01N 17/00 dated 06/26/2006). The essence of the invention lies in the fact that monitoring the state of the reinforcement of the underground part of reinforced concrete supports is carried out by an indicator sample. The indicator sample is made of the same material as the support armature. The assessment of the condition of the reinforcement is determined by the thickness of the indicator sample and the period of time until its destruction. An indicator sample is placed around the reinforcement and create contact with it at one point. Insulated conductors are connected to the ends of the indicator sample, the ends of which are brought to the surface of the support above the burial level. The moment of destruction of the indicator sample is determined by periodically measuring its resistance.

The disadvantages of this method are:

- unreliability of contact of the indicator sample with the reinforcement;

- the difficulty of determining the moment of destruction of the indicator sample;

- the lack of data on the corrosion state of the reinforcement, in particular the inability to determine the time dependence of the corrosion rate in time.

The technical problem to be solved by the claimed invention is directed is the creation of a method and a device for contacting a control unit for parameters of electrochemical protection with a pipe coated with a weighting concrete coating, providing increased reliability of contact of a control unit for controlling parameters of electrochemical protection with a pipe with a weighting concrete coating, increasing the accuracy of determination corrosion characteristics of pipe steel, which is a model element of the pipe, and the assessment is protected pipe corrosion and the effectiveness of electrochemical protection at the same time.

The problem is solved as follows.

On the outer surface of the pipe using synthetic clamps, clamps, a steel fixing pad is attached. A mortgage nut is installed in it, into which a special bolt-screw is screwed with the cutting part of the drill for drilling a weighting coating. Rotating the knob, drill a weight coating with an insulating coating until the cutting part of the drill contacts the pipe metal. Take the drill out of the hole and replace the mortgage nut with a second mortgage nut, with another screw. A capsule is installed in the hole with the cable facing out. A metal washer is placed on top of the capsule. The capsule is made of rubber in the form of a cylinder, inside of which a contact assembly with a conical and cylindrical threaded part is placed. The conical part is designed to make contact with the tube when compressing the capsule with a screw. The bare part of the cable is attached to the threaded part. The capsule is made in such a way that the entire contact assembly is located inside the rubber cylinder and is completely isolated from the external environment.

After installing the capsule in the hole in the weighting coating, the capsule is compressed by rotation of the screw until stable contact of the cable with the pipe is achieved. Contact tightness is ensured by placing all parts of the contact assembly inside the rubber cylinder and displacing the fluid from the space surrounding the contact.

The cubic-shaped electrochemical protection parameters control unit consists of a weighting material made of the same material as the weighting material on the pipe, inside of which are placed elements that control the protection parameters: two indicators for monitoring the corrosion rate and two electrodes for comparison with potential sensors. One indicator of control of the corrosion rate and one sensor of the potential of the reference electrode are connected to the pipeline via a cable, which is removed from the capsule contact to the control unit for the parameters of electrochemical protection. The second indicator of the corrosion rate control and the second potential sensor of the second reference electrode are not connected to the pipeline.

Thanks to this connection, defects in the insulation coating are modeled with bare metal of the pipe surrounded by the weighting coating.

On these simulated defects, using the sensors of the potential of the reference electrodes and sensors of the corrosion rate, the stationary (natural) and polarization potentials, as well as the corrosion rate without and in the presence of electrochemical protection, are measured.

By subsequent calculations, the effectiveness of the electrochemical method of protection and corrosion protection are determined.

The technical result can be achieved using the present invention by creating a tight contact between the metal of the pipe and cable connected to the control unit for the parameters of electrochemical protection, as well as by using a special set of sensors (two electrodes for comparison with potential sensors and two indicators of corrosion rate), which determine the assessment pipe protection against corrosion and the effectiveness of electrochemical protection at the same time.

The claimed invention is illustrated by drawings.

Figure 1 shows the appearance of the pipe with a steel fixing pad fixed with synthetic clamps.

Figure 2 presents the mortgage nut with a bolt-screw in the fixing area.

Figure 3 presents the second embedded nut with a bolt, a blind hole and a capsule.

Figure 4 shows a top view of the second gate, the capsule and cable.

Figure 5 shows the capsule before (left) and after exposure.

Figure 6 shows a pipe, a nut with a second winch and a weighting agent.

In Fig.7 shows a control unit for the parameters of electrochemical protection.

On Fig shows a pipe with a connected unit for monitoring the parameters of electrochemical protection.

Figure 9 shows the screen and power elements.

The installation depicted in figure 1, consists of a pipe 1, synthetic clamps-clamps 2, a steel fixing pad 3, having a slot 4 and grooves 5.

The embedded nut with a bolt-screw, shown in Fig.2, consists of a mortgage nut 6 with ledges 7 included in the grooves 5 of the steel fixing pad 3, the bolt-collar 8 with the cutting part of the drill 9. The bolt-screw contacts three layers: coating 10, insulation coating 11 and metal pipe 12.

Figure 3 shows a blind hole 13, the second nut 14, the second bolt - the screw 15, the capsule 16 and the cutting part of the drill 17 of the second bolt-screw 15.

Figure 4 shows the slot 4, the visible part of the second nut 14, the second knob 15, the capsule 16, cable 18 and the washer 19.

Figure 5 presents the capsule 16 in the form of a rubber cylinder 20, a metal washer 19, a contact node 21, consisting of a conical part 22 and a cylindrical threaded part 23, the bare part 24 of the cable 18. On the right is an additional metal contact 25 of the conical part 22 and the pipe metal 12.

Figure 6 presents the pipe 1, synthetic clamps-clamps 2, steel fixing pad 3, cable 18 and weighting agent 26.

The control unit for the parameters of electrochemical protection, shown in Fig. 7, consists of a weighting agent 26, corrosion rate indicators 27 and 28, two comparison electrodes 29 and 30 with potential sensors 31, 32, leads from corrosion rate indicators 33, 34, leads from comparison electrodes 35-39, voltmeters 40, 41, ammeter 42.

On Fig presents a pipe 1 with a layer of a weighting coating 10, in which with the help of a cable 18 is attached a control unit for the parameters of electrochemical protection 26 with a screen 43.

Figure 9 presents the screen 43 and the power elements 44.

The method of making contact and the device that allows you to create contact can be described as follows.

On the outer surface of the pipe 1, using synthetic clamps-clamps 2, a steel fixing pad 3 is fastened. A slot 4 is made to the middle of the fixing pad 4 with dovetail grooves 5 made on both sides of the groove. A mortise nut 6 is installed in the slot with a groove 6 with ledges 7, which are inserted into the grooves 5 of the steel fixing pad 3 as far as the stop at the end of the slot 4. A special bolt 8 is screwed into the nut 6, in the lower part of which the cutting part of the drill is fixed by welding 9. Cutting part of the drill 9 is designed for drilling a weighting coating 10. Rotating the bolt-screw 8, drill a weighting coating 10 with an insulating coating 11 until the cutting part of the drill 9 comes into contact with the metal of the pipe 12. After the blind hole 13 is made in weighting coating 10, rotating the drill 8 in the opposite direction from the drilling, lead the drill 9 out of the hole and replace the nut 6 with the second nut 14, with another screw 15. Before installing the second nut 14, clean the hole 13 made of residual drilling products and install in him capsule 16. The capsule is installed so that the cable 18 goes out. A metal washer 19 is placed on top of the capsule, the diameter of which is equal to the diameter of the hole 13 made in the weighting coating 10. The washer 19 is designed to prevent squeezing a part of the rubber cylinder 20 outward when it deforms during (and after) its compression by the screw 17.

The capsule 16 is made of rubber in the form of a cylinder 20, inside of which the contact node 21. The contact node 21 has a conical part 22 and a cylindrical threaded part 23. The conical part 22 is designed to contact the pipe 1 when the capsule 16 is compressed by the screw 17. On the threaded part 23 fasten the bare part 24 of the cable 18. The capsule 16 is made in such a way that the entire contact node 21 (with the bare part 24 of the cable 18) is inside the rubber cylinder 20 and is completely isolated from the external environment.

After installing the capsule 16 in the hole 13 made in the weighting coating 10, installing the nut 14 with the screw 17 and the washer 19, rotating the screw 17 compress the capsule 16 until the cable 18 is in steady contact with the pipe 1. The control of the contact of the cable 18 with the pipe 1 is controlled by resistance, which (minus the resistance of cable 18 and pipe 1) should be equal to not more than 0.1 Ohm (the measurement of resistance is not shown in the figure).

When the capsule 16 is compressed by the screw 17, at the initial moment, the diameter of the capsule 16 increases and the outer surface of the capsule 16 becomes denser to the walls of the opening 13. In this case, liquid is displaced from the cavity between the wall of the opening 13 in the weighting coating 10 and the outer surface of the capsule 16. With an increase in the axial the compressive forces of the capsule 16 increases the radial compaction force. In addition, the conical part of the contact 22, under the action of increasing axial force from the collar 15, is forced out of the inner part of the capsule 16 to the outside and makes contact with the outer part of the pipe wall 12.

The tightness of the contact is ensured by placing all parts of the contact node 21 inside the rubber cylinder 20 and displacing the liquid from the space surrounding the contact 25.

Thus, create a tight contact of the pipe metal with the cable, which is then connected to the control unit of the parameters of electrochemical protection.

The control unit for the parameters of electrochemical protection is designed to control the operation of electrochemical protection on pipes coated with a weighting coating. The device is installed in close proximity to the pipe and is a set of elements designed to control the cathodic protection parameters.

The cubic-shaped block consists of a weighting material 26 made of the same material as weighting material 10 on the pipe 1, inside of which are placed elements that control the protection parameters: two indicators for monitoring the corrosion rate 27 and 28, two reference electrodes 29, 30 with potential sensors 31 and 32. One indicator of corrosion rate control 27 through terminal 33 and one potential sensor 32 of reference electrode 30 through terminal 39 are connected to pipe 1 via cable 18. Second corrosion rate indicator 28 and second potentiometer iala 31 of the second reference electrode 29 to the pipe 1 is not connected.

Due to this connection, defects in the insulation coating 11 are simulated with the metal of the pipe 12 surrounded by the weighting coating 10 exposed. Potential sensors 31, 32 and corrosion control indicators 27 and 28 become model defects in the insulation coating 11, i.e. acquire the properties of the metal pipe 12.

Thus, the weighting agent 26 models the weighting agent 10.

Using indicators of corrosion rate control 27 and 28, the corrosion rate of metal 12 of the outer wall of the pipe 1 is monitored under the weighting coating 10 when exposed to cathodic protection (corrosion rate indicator 27) and without it (corrosion rate indicator 28).

Using the reference electrode 29 with the potential sensor 31, the stationary potential of the pipe 1 is monitored in a corrosive pipeline environment, i.e. under the weighting coating 26, which simulates the coating 10. The measurement of the stationary potential is as follows. A high-resistance voltmeter 40 is connected between the terminals 35 and 36 from the reference electrode (not shown in the figure) and the potential sensor 31.

Using a reference electrode 30 with a potential sensor 32, the polarization potential of the pipe 1 is monitored in a corrosive pipeline environment, i.e. under the weighting coating 26, which simulates the coating 10. The measurement of the polarization potential is as follows. A high-resistance voltmeter 41 is connected between the terminals 37 and 38 from the reference electrode (not shown in the figure) and the potential sensor 32. The cathode current density is measured by connecting an ammeter 42 to the open circuit of the 32-terminal 39 potential sensor.

In a particular case, the control unit for the parameters of the electrochemical protection 26 can be located in the layer of the weighting concrete coating 10 on the pipe 1. In this case, the cable 18 from the contact 25 can also be located in the layer of the weighting concrete coating 10. The appearance of the pipe 1 does not change. But at the same time, elements appearing in the weighting coating 10 make it possible to evaluate corrosion protection. Voltmeters, corrosion gauges (not shown in the figure) may have a screen 43 with an indication of the parameters and the effectiveness of the electrochemical protection and supplying the screen 43 with photosensitive elements 44, activated in the presence of light. For example, a robot approaches the pipe 1 (not shown in the figure), illuminates the screen 43 and the photosensitive elements 44, and data on the polarization, stationary potentials, corrosion rate during protection and in the absence of protection, and also the level of protection against corrosion appear on it. In a particular case, the screen can be powered by chemical sources of current, such as batteries, batteries. In a particular case, the screen can be powered by an EMF generated between the steel fixing pad and the tread with a potential more negative than the potential of the steel fixing pad.

The effectiveness of the electrochemical method of protection is characterized by the degree of protection P,% [Krasnoyarsky V.V. Electrochemical method of protecting metals from corrosion. M .: Mashgiz, 1961, 56 pp.]

$$P=\frac{{\mathrm{TO}}_{\mathrm{to}\mathrm{about}R}+{\mathrm{TO}}_{\mathrm{to}}}{{\mathrm{TO}}_{\mathrm{to}\mathrm{about}R}}\cdot \mathrm{one\; hundred}\left(\mathrm{one}\right)$$

where K _cor - corrosion rate at a stationary potential, mm / year;

To _to - the corrosion rate at cathodic protection, mm / year.

In our case, K _cor is the corrosion rate shown by the corrosion rate indicator 28 not connected to the cathodic protection system, and K _k is the corrosion rate indicated by the indicator 27 connected to the cathodic protection system.

Using formula 2, with the potential difference ΔЕ between the cathodic polarization potential (polarization potential) and the stationary potential of more than 100 mV, the degree of protection is at the level of 99% and does not depend on the further potential shift to the negative [Krasnoyarsky V.V. Electrochemical method of protecting metals from corrosion. M .: Mashgiz, 1961.56 p.].

$$\Delta E=E_{P\mathrm{about}l\mathrm{I\; am}R}-E_{\mathrm{from}t\mathrm{but}c}\left(2\right)$$

In our case, E _polar is the potential of the potential sensor 32 connected to the cathodic protection system, and E _stats is the potential of the corrosion sensor 31 not connected to the cathodic protection system.

For the necessary and sufficient corrosion protection it is necessary to achieve 99% corrosion protection. The latter can be determined using two corrosion indicators or two reference electrodes. If two pairs show a degree of protection of at least 99%, the pipe can be considered protected against corrosion.

As reference electrodes with potential sensors, it is preferable to use reference electrodes that directly measure the polarization potential, using a conventional high-resistance voltmeter, without the use of special measuring instruments.

As indicators of the corrosion rate, it is preferable to use discrete intelligent indicators of the corrosion rate, consisting of the nth number of plates and showing the change in the corrosion rate over time and the total depth of corrosion. It is possible to use corrosion rate sensors operating on the principle of linear polarization resistance.

The method of making contact using a steel fixing pad is preferable when making contact under water, for example, at pipeline crossings through water barriers (rivers, swamps) or in sea water.

In this case, the contact can be made on a pipe having the following structure (from the outside to the inside): weighting concrete coating, insulation coating, metal pipe.

In a particular case, contact can be made on a pipe having the following structure: a metal-polymer shell (for example, galvanized steel shell with an insulating coating), a weighting concrete coating, an insulating coating, and a metal pipe.

A contact method in which the electrochemical protection parameter monitoring unit is flush with the concrete surface is preferred at the pipe manufacturer.

Improving the reliability of the contact of the control unit parameters of electrochemical protection with a pipe with a weighting concrete coating is achieved by creating a sealed contact using expanding when exposed to a capsule.

Improving the accuracy of determining the corrosion characteristics of pipe steel, which is a model element of the pipe, as well as assessing the protection of the pipe against corrosion and the effectiveness of electrochemical protection is achieved by the simultaneous use of two reference electrodes with potential sensors and two indicators of corrosion rate.

Claims (6)

1. A method for contacting a control unit for parameters of electrochemical protection with a pipe coated with a weighting concrete coating, in which a contact is made for a control unit for controlling parameters of electrochemical protection with a pipe having a weighting concrete coating, characterized in that clamps are fastened to the pipe with a weighting concrete coating steel fixing pad having a slot and grooves for fastening a nut with a screw-bolt having a cutting part of the drill, which when the bolt rotates The layer of weighting concrete coating passes successively, the insulation coating exposing the metal of the pipe, then the bolt is removed, a capsule with a cable is inserted into the blind hole, at the end of which there is an electrochemical protection control unit, a washer is placed on the capsule, a second mortgage insert is inserted into the fixing pad a nut with a second screw-bolt with a cutting part of the drill; when the second screw-bolt rotates, the capsule is compressed until the capsule cable contacts the pipe. 2. The method according to claim 1, characterized in that the cutting part of the drill rotates a layer of metal-polymer shell, a layer of a weighting concrete coating, an insulation coating, exposing the metal of the pipe. 3. A device for making contact of the control unit of the parameters of electrochemical protection with a pipe coated with a weighting concrete coating, containing a steel fixing pad having a slot and grooves and secured to the pipe with clamps, characterized in that the slot and grooves of the steel fixing pad are installed mortgage nut with a screw-bolt, consisting of a mortgage nut with ledges included in the grooves of the steel fixing pad, a bolt-screw with a cutting part of the drill, capsule with washer and cable, hair capsule is represented as a cylinder and consists of a contact assembly with a tapered portion in contact with the pipe and a cylindrical threaded portion in which the bare portion of the cable that goes to the power control parameters of electrochemical protection. 4. The device according to claim 3, characterized in that it is flush with the surface of the weighting concrete pavement and has a screen with an indication of the parameters, which is powered by photosensitive elements. 5. The device according to claim 3, characterized in that it is flush with the surface of the weighting concrete pavement and has a screen with an indication of the parameters, which is powered by chemical current sources. 6. The control unit of the parameters of electrochemical protection as part of a device for making contact of the control unit of parameters of electrochemical protection with a pipe coated with a weighting coating, comprising a weighting material connected via a cable to the pipe, characterized in that two weighting electrodes are located in the weighting compound, each with a potential sensor, and two indicators of corrosion rate, and one of the potential sensors of one reference electrode and one indicator of corrosion rate are connected via a cable to the pipe, m A voltmeter is connected between the output from the comparison electrode and the output from the potential electrode of the comparison electrode with potential sensor No. 1, a voltmeter is connected between the output from the comparison electrode and one of the two conclusions from the potential electrode of the comparison electrode and potential sensor No. 2, the sensor of the comparison electrode is open with potential sensor number 2-cable connected ammeter.

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