CN212894991U

CN212894991U - Steel member potential measurement system

Info

Publication number: CN212894991U
Application number: CN202021995370.0U
Authority: CN
Inventors: 张兴莉
Original assignee: Individual
Current assignee: Li Tao
Priority date: 2020-09-11
Filing date: 2020-09-11
Publication date: 2021-04-06
Anticipated expiration: 2030-09-11

Abstract

The utility model relates to an electrochemistry technical field, more specifically relates to a steel member potential measurement system. The method is used for solving the problem that the potential measurement value deviation of the steel member is large when various electromagnetic interferences exist in the electrolyte environment. The steel member potential measuring system comprises a steel member, a Faraday cage, a direct current potential difference meter, a reference electrode, a temperature and pH probe and a temperature and pH meter; the steel component is arranged outside the Faraday cage, and the reference electrode is arranged inside the Faraday cage; the steel member, the direct current potential difference meter and the reference electrode are connected through a lead; the Faraday cage is also internally provided with a temperature and pH probe which is connected with a temperature and pH meter through a lead; the Faraday cage is used for shielding electromagnetic interference outside the cage and preventing a reference electrode and a temperature and pH probe in the cage from being subjected to the electromagnetic interference. The technical effect of accurately measuring the potential of the steel member can be achieved by shielding the influence of various electromagnetic interferences existing in the electrolyte environment on the potential measurement work through the technical scheme.

Description

Steel member potential measurement system

Technical Field

The utility model relates to an electrochemistry technical field, more specifically relates to a steel member potential measurement system.

Background

As cities develop, various power cables increase greatly, and these devices inevitably generate stray currents flowing through the ground in operation. This part is strayThe current (or called labyrinth current) can not only generate serious electrochemical corrosion action on the exposed surfaces of steel materials such as underground pipelines, measuring signal lines, reinforcing steel bars and the like, but also greatly accelerate the corrosion speed, so that the working effect of the cathode protection system is not good enough, even the cathode protection system fails; these stray currents also have a severe influence on the electrical potential E of the steel component_SteelThe measurement of (2).

Measuring polarization potential E of certain steel member in electrolyte environment_SteelIt is the basic condition for the application of cathodic protection technology. To measure the polarization potential E_SteelOn the basis of the polarization circuit, another measurement circuit is introduced, in which there is a reference electrode whose polarization potential E is required_{Ginseng radix (Panax ginseng C.A. Meyer)}Known and stable. At present, in the field environment, a direct current voltmeter is generally adopted to measure the potential difference E between the steel member and the reference electrode_Steel－E_{Ginseng radix (Panax ginseng C.A. Meyer)}. As shown in detail in fig. 2.

The direct-current voltmeter is used as a potential difference measuring instrument, is only suitable for a polarization loop without being put into operation, and the instrument is only used for measuring the natural corrosion potential E of the metal material_{1 steel}The error is smaller (as described in detail in the other application, a faraday cage for use in an electrolyte environment). When the polarization loop is put into operation, however, a polarization loop is formed between the anode and the polarized steel component, and a polarization current I exists in the polarization loop_Pole(s). So as to polarize the current I_Pole(s)And measuring the current I_MeasuringThe solution flows through the ion circuit section between the steel component and the reference electrode together, and the solution resistance on the ion circuit section is R_uSo that the value of the ohmic drop of the solution is changed to IR_u＝(I_Pole(s)+I_Measuring)×R_u(ii) a This value is directly superimposed on the reading of the measuring voltmeter, which causes a large measuring error.

Polarization current I_Pole(s)Changing the potential of the steel member from E before polarization_{1 steel}Changed into polarized E_{1 steel}+E_{2 steel}(ii) a The reference electrode is also subjected to a polarization current I_Pole(s)Has an influence of_{1 Ginseng radix}Become E_{1 Ginseng radix}+E_{2 Ginseng radix}. Note: above E_{2 steel}Subjecting the steel member to a polarization current I_Pole(s)The influence of (2), a value that causes a change in self potential; e_{2 Ginseng radix}The reference electrode is subjected to a polarization current I_Pole(s)The influence of (c) results in a value of change in self potential.

To E_{2 Ginseng radix}Then, the analysis is carried out, and it is known that it comprises two parts, E_{2 Ginseng radix}＝E_{2 ginseng-anode}+E_{2 ginseng-cathode}。E_{2 ginseng-anode}Is a polarization current I emitted from the anode_Pole(s)A value that polarizes the reference electrode when reaching the reference electrode through the ion path, resulting in a change in the potential of the reference electrode; e_{2 ginseng-cathode}Is the potential of the steel member generates E_{2 steel}This potential change, in turn, affects the potential of the reference electrode through the electronic channels in the measurement circuit, resulting in a value of change in the potential of the reference electrode.

At this time, the meter reading expected by the measurer is V_{Voltage meter}＝(E_{1 steel}+E_{2 steel}－E_{1 Ginseng radix}) But actually V_{Voltage meter}＝[(E_{1 steel}+E_{2 steel})－(E_{1 Ginseng radix}+E_{2 Ginseng radix})]－(I_Pole(s)+I_Measuring)×R_u. Wherein (I)_Pole(s)+I_Measuring)×R_uAnd E_{2 Ginseng radix}Are the interference factors that should be eliminated, these influence factors now being V_{Voltage meter}The value of (A) is about 0.2 v-0.5 v, so it is completely non-negligible in engineering practice and must be eliminated by taking measures. At present, most of the methods of using the polarization test piece to cut off the power instantly have the problems of slow measuring speed, multiple restriction conditions, poor precision and poor repeatability, and especially the method only eliminates (I)_Pole(s)+I_Measuring)×R_uTo E, for_{2 Ginseng radix}The force is completely ineffective. In addition, there is a polarized probe method improved on the basis of polarized test piece instantaneous power-off method, which can partially eliminate E_{2 Ginseng radix}However, the influence of (A) cannot be completely eliminated, and it is unclear how much E is eliminated_{2 Ginseng radix}The influence of (c).

If in the electrolyte environment, direct or alternating current is also presentStray current I of current_{Hetero compound}Disturbance, stray current I under such conditions_{Hetero compound}Also flows through the solution section between the cathode and the reference electrode through the ion path, so that the ohmic drop value of the solution is changed into IR_u＝(I_Measuring +I_Pole(s)+I_{Hetero compound})×R_uThis value is also superimposed on the reading of the measuring voltmeter. While stray current I_{Hetero compound}Also changes E_SteelAnd E_{Ginseng radix (Panax ginseng C.A. Meyer)}Numerical value of (E)_{1 steel}+E_{2 steel}To become E_{1 steel}+E_{2 steel}+E_{3 steel}，E_{1 Ginseng radix}+E_{2 Ginseng radix}To become E_{1 Ginseng radix}+E_{2 Ginseng radix}+E_{3 Ginseng radix}. Wherein E_{3 steel}Is a stray current I_{Hetero compound}A value that causes a change in the potential of the steel structure when flowing through the steel structure; e_{3 Ginseng radix}The reference electrode is subjected to a stray current I_{Hetero compound}The influence of (c), a value that causes a change in the potential of the reference electrode.

To E_{3 Ginseng radix}Then, the analysis is carried out, and it is known that it comprises two parts, E_{3 Ginseng radix}＝E_{3 Ginseng and stray}+E_{3 ginseng-cathode}。E_{3 Ginseng and stray}Is stray current I emitted by interference source_{Hetero compound}A value that interferes with the reference electrode after reaching the reference electrode to cause a change in the potential of the reference electrode; e_{3 ginseng-cathode}Is the stray current I of the steel member_{Hetero compound}After the disturbance, its potential changes E_{3 steel}And this change, in turn, through the electronic channel in the measurement loop, interferes with the reference electrode, resulting in a value of change in the potential of the reference electrode.

Therefore, the measurement loop is subjected to stray current I_{Hetero compound}In the influence of (2), the meter reading V expected by the measurer_{Voltage meter}＝(E_{1 steel}+E_{2 steel}+E_{3 steel}－E_{1 Ginseng radix}) But actually becomes V_{Voltage meter}＝[(E_{1 steel}+E_{2 steel}+E_{3 steel})－(E_{1 Ginseng radix}+E_{2 Ginseng radix}+E_{3 Ginseng radix})]－(I_Pole(s)+I_Measuring +I_{Hetero compound})×R_uWherein (I)_Pole(s)+I_Measuring+I_{Hetero compound})×R_uAnd E_{2 Ginseng radix}+E_{3 Ginseng radix}Is the interference factor that should be eliminatedElements, these influencing factors being represented by V_{Voltage meter}The numerical value in the test strip can be as high as several volts or even dozens of volts, and is far away from the normal value or the accurate value, but no effective measure or method is available at present to eliminate the interference factors, and the accurate data can not be measured by the existing polarization test strip instantaneous power-off method and the polarization probe method.

Second, direct current potential difference meter based on adjustable balance principle design

A dc potentiometer is an instrument constructed using the compensation principle. The compensation method is characterized in that current is not taken from a measuring object, so that the measured value is not interfered, and the measuring result is accurate and reliable. When no current flows, the potential difference between the positive and negative electrodes of the battery is equal to the electromotive force of the battery. If current flows, there is a certain voltage drop in the internal resistance of the battery (as is the case when the voltage between the two poles of the battery is measured by a voltmeter), and the voltage measured at this time is no longer the electromotive force of the battery, but only the terminal voltage. If the measurement can be performed when no current flows, the electromotive force can be directly measured. One such method is the compensation method.

The direct current potential difference meter is matched with appliances such as a standard battery and a standard resistor, so that the direct current potential difference meter can measure electrical quantities such as electromotive force, potential difference (voltage), current, resistance and the like with high accuracy; and various transducers are matched, and the device can also be used for measuring and controlling non-electric quantities such as temperature, displacement and the like. The potentiometer is divided into a direct current potentiometer and an alternating current potentiometer. With the continuous development and perfection of the theory and technology of the direct current comparator, a direct current comparator type direct current potentiometer with high accuracy appears, and the measurement error of the direct current comparator type direct current potentiometer is about one millionth order of magnitude. The AC potentiometer is used for measuring the sine AC voltage from power frequency to audio frequency, but only products for power frequency exist in the market, and the AC potentiometers with other frequencies are required to be designed and manufactured by themselves.

The traditional direct current potential difference meter is generally mechanical, is complex to use, slow in measurement speed, high in price and multiple in influencing factors of the measurement process, so that the direct current potential difference meter is generally only used in occasions such as laboratories or instrument correction, and is rarely used in field environments. However, with the continuous progress of electrical and electronic technology, many commercial digital dc potentiometers have appeared, which basically solve the disadvantages of the mechanical dc potentiometers. The digital DC potentiometer adopts advanced digitization and intelligent technology to combine with the traditional technology, completely covers the novel product of the original DC potentiometer in use function, and can precisely detect millivolt signals output by primary instruments such as thermocouples, sensors, transmitters and the like.

Thirdly, the natural corrosion potential E of the metal material under the environment of the electrolyte_{1 steel}Measurement of

When a metal material (such as a steel member) is in an electrolyte environment, an electric double layer interface is formed on the contact surface of the steel material surface and the electrolyte, and atoms of the metal chemically react with the electrolyte at the electric double layer interface to generate a polarization potential E_SteelThis polarization potential is referred to as the natural corrosion potential, referred to herein as E_{1 steel}. Measuring the natural corrosion potential E of a steel member in an electrolyte environment_{1 steel}It is one of the basic conditions for the application of cathodic protection technology. To measure E_{1 steel}Another reference electrode is introduced, the polarization potential E of which is required_{Ginseng radix (Panax ginseng C.A. Meyer)}Known and stable. Measuring the DC potential difference E between a steel component and a reference electrode with a meter_{1 steel}－E_{Ginseng radix (Panax ginseng C.A. Meyer)}The natural corrosion potential E can be calculated_{1 steel}Numerical values. As shown in detail in fig. 2.

In current practice, a voltmeter is generally used as a measuring instrument. The positive electrode of the voltmeter is required to be electrically connected with the steel component, the negative electrode of the voltmeter is electrically connected with the reference electrode, a closed measuring loop with an electronic circuit and an ionic circuit is formed, and a measuring current I is formed in the loop_Measuring. Reading V of the voltmeter at this time_{Voltage meter}Actually, the voltage at the end of the line is analyzed to obtain V_{Voltage meter}＝I_Measuring×R_{Voltage meter}＝(E_{1 steel}－E_{Ginseng radix (Panax ginseng C.A. Meyer)})－I_Measuring×R_uThe reading is not intended by the measurer (E)_{1 steel}－E_{Ginseng radix (Panax ginseng C.A. Meyer)}) The inside also contains an influencing factor I_Measuring×R_u. V in the above formula_{Voltage meter}Is a voltageA reading of the meter; e_{1 steel}The steel member is in the electrolyte environment, and the natural corrosion potential is generated due to natural corrosion; e_{Ginseng radix (Panax ginseng C.A. Meyer)}The reference electrode is a natural corrosion potential generated by the natural corrosion action in the electrolyte environment; i is_MeasuringIs the current flowing in the measurement circuit; r_uIs the ionic circuit resistance between the measured electrode and the reference electrode; r_{Voltage meter}To measure the internal resistance of the voltmeter.

In practical application, if the internal resistance R of the voltmeter is_{Voltage meter}Higher, up to R_{Voltage meter}＞R_uAt x 1000, I_Measuring×R_uCan be ignored and considered as the voltage meter measured value V_{Voltage meter}≈(E_{1 steel}－E_{Ginseng radix (Panax ginseng C.A. Meyer)}). At the current electronic industry level, the resistance of the digital voltmeter reaches 10 basically⁷～10⁹Is much larger than R_{Voltage meter}＞R_uRequirement for x 1000 (R)_uTypically hundreds or thousands of ohms) so that the measurement needs can be satisfied by using a digital voltmeter with high internal resistance under a two-electrode system.

When a balance-adjustable DC potentiometer is selected to replace a voltmeter as a measuring instrument, the internal resistance of the DC potentiometer tends to infinity, a measuring circuit forms a virtual break condition, and the measuring current I can be considered to be measured_MeasuringIs not present at this time, resulting in I_Measuring×R_uAt the same time, it does not exist, so that the reading E of the direct current potential difference meter_{DC potentiometer}＝(E_{1 steel}－E_{Ginseng radix (Panax ginseng C.A. Meyer)})。

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at overcoming above-mentioned prior art's at least one defect (not enough), provide a steel member potentiometric measurement system for when solving the various electromagnetic interference that exist in the electrolyte environment, seriously influence the problem of steel member potentiometric measurement accuracy, with the realization to the electromagnetic shielding of carrying on of the various electromagnetism that exist in the electrolyte environment, the technological effect of accurate measurement steel member potential.

The utility model adopts the technical proposal that a steel component potential measuring system comprises a steel component, a Faraday cage, a direct current potential difference meter, a reference electrode, a temperature and pH probe and a temperature and pH meter; the steel member is arranged outside the Faraday cage, the reference electrode is arranged inside the Faraday cage, and the steel member, the direct current potential difference meter and the reference electrode are connected through a lead to form a closed loop circuit; the Faraday cage is also internally provided with a temperature and pH probe which is connected with a temperature and pH meter through a lead; the Faraday cage is used for shielding electromagnetic interference outside the cage and preventing a reference electrode and a temperature and pH probe in the cage from being subjected to the electromagnetic interference.

Further, the Faraday cage comprises an outer metal gauze, a cage body and an inner metal gauze three-layer structure; the outer metal gauze is arranged on the outer wall of the cage body, and the inner metal gauze is arranged on the inner wall of the cage body; the cage body is made of non-conductive non-metal materials, and the inner metal gauze and the outer metal gauze are made of metal materials with strong conductivity.

Furthermore, the inner metal gauze and the outer metal gauze are separated by the cage body and are not contacted with each other; the inner and outer metal screens are also free from contact with other conductive materials.

Furthermore, holes are formed in the cage body, and yarn holes are formed in the inner metal gauze and the outer metal gauze and can ensure that electrolyte freely enters or flows out of the Faraday cage.

Furthermore, a protective layer is arranged on the inner side of the inner metal gauze and the outer side of the outer metal gauze; the protective layer is made of non-conductive materials and is provided with holes.

Furthermore, the inner metal gauze and the outer metal gauze are provided with more than two layers. Both the inner and outer metal screens are in fact grounded.

Further, the steel member potential measuring system is constructed based on a Faraday cage operating in an electrolyte environment, a DC potentiometer and a reference electrode.

Furthermore, the reference electrode, the temperature and pH probe are arranged in the inner space of the Faraday cage, and the measurement components are selected according to the requirements of relevant regulations; the steel member to be measured is located in the outer space of the faraday cage.

Further, a switch K2 and a dc potentiometer were arranged between the steel member and the reference electrode. The temperature & pH probe is also connected with the temperature & pH meter through a circuit.

Furthermore, the direct current potential difference meter is designed based on an adjustable balance principle, and the measurement precision of the direct current potential difference meter is required to be within 1 mv.

Further, according to DC potential difference meter and temperature&The measured result of the pH meter can be calculated to obtain the accurate steel material potential E according to the relevant electrochemical formula_Steel。

Further, the steel member, faraday cage, reference electrode and temperature & pH probe are completely immersed in an electrolyte environment.

Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses a design a Faraday cage of being applied to in the electrolyte environment to place the steel member in the outside of Faraday cage, reference electrode and temperature & pH probe are placed in the inside of Faraday cage, and measure the potential difference data in the closed circuit that steel member and reference electrode formed through the direct current potential difference meter, cooperate temperature & pH probe and temperature & pH meter to measure simultaneously; the Faraday cage can play a role in shielding electromagnetic interference outside the cage during measurement, and the potential of the steel member can be accurately calculated by combining the measurement data of the temperature and pH meter.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

FIG. 2 is a schematic circuit diagram of a three-electrode system.

Description of reference numerals: faraday cage 1, cage body 2, hole 3, inner metal gauze 4, outer metal gauze 5, steel component 6, underground water line 7, switch 21, direct current potentiometer 22, reference electrode 23, temperature & pH meter 32, temperature & pH probe 33.

Detailed Description

The drawings of the present invention are for illustration purposes only and are not to be construed as limiting the invention. For a better understanding of the following embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

Example 1

As shown in fig. 1, the steel member potential measuring system of the present embodiment is characterized by comprising a steel member 6, a faraday cage 1, a direct current potentiometer 22, a reference electrode 23, a temperature & pH probe 33, and a temperature & pH meter 32; the steel component 5 is arranged outside the Faraday cage 1, and the reference electrode 23 is arranged inside the Faraday cage 1; the steel component 6, the direct current potential difference meter 22 and the reference electrode 23 are connected through leads to form a closed loop circuit; a temperature and pH probe 33 is further arranged inside the Faraday cage 1, and the temperature and pH probe 33 is connected with a temperature and pH meter 32 through a lead; the steel member 6, the Faraday cage 1, the reference electrode 23 and the temperature and pH probe 33 are completely immersed in an electrolyte environment; the Faraday cage 1 is used for shielding electromagnetic interference outside the cage from entering the cage, and the reference electrode 23 and the temperature and pH probe 33 in the cage are prevented from being subjected to electromagnetic interference.

More specifically, the faraday cage 1 comprises a three-layer structure of an outer metal gauze 5, a cage body 2 and an inner metal gauze 4; the outer metal gauze 5 is arranged on the outer wall of the cage body 2, and the inner metal gauze 4 is arranged on the inner wall of the cage body 2; the cage body 2 is made of a non-conductive non-metal material, and the inner metal gauze 4 and the outer metal gauze 5 are made of metal materials with strong conductivity.

The inner metal gauze 4 and the outer metal gauze 5 are separated by the cage body 2 and are not contacted with each other; the inner and

outer metal screens

4, 5 are also not in contact with other conductive materials.

The Faraday cage is characterized in that holes 3 are formed in the cage body 2, yarn holes are formed in the inner metal gauze 4 and the outer metal gauze 5, and the holes 3 and the yarn holes can ensure that electrolyte freely enters or flows out of the Faraday cage 1.

The inner side of the inner metal gauze 4 and the outer side of the outer metal gauze 5 are provided with protective layers; the protective layer is made of non-conductive material and is provided with a hole 3.

The inner metal gauze 4 and the outer metal gauze 5 are provided with more than two layers. Both the inner 4 and outer 5 metal screens are in fact grounded.

The direct current potentiometer 22 is designed based on an adjustable balance principle, and the measurement precision of the direct current potentiometer is required to be within 1 mv.

When the switch k2 in the present system is turned on, the dc potentiometer 22 starts to operate and obtain a reading.

Since the working principle of the DC potentiometer 22 is different from that of a voltmeter, a measuring loop cannot be formed, and therefore the measuring current I is measured_MeasuringIs absent; with the result of a polarization current I_Pole(s)Formed of_Pole(s)×R_uFrom stray currents I_{Hetero compound}Formed of_{Hetero compound}×R_uNone of the values can enter E_{DC potentiometer}In the reading of (A), therefore_Pole(s)+I_Measuring+I_{Hetero compound})×R_uThe effect of (2) is eliminated.

Due to the internal resistance R of the DC potentiometer 22_{DC potentiometer}Tending to infinity, resulting in a "virtual break" in the measurement loop. At this time, E occurs in the potential of the cathode_{2 steel}、E_{3 steel}The change can not cause the potential of the reference electrode 23 to appear E any more due to the blocking effect of the DC potentiometer 22_{2 ginseng-cathode}、E_{3 ginseng-cathode}A change of (i), i.e. E_{2 Ginseng radix}E in (A)_{2 ginseng-cathode}、E_{3 Ginseng radix}E in (A)_{3 ginseng-cathode}Cannot be formed in the present measurement system.

Or because of the internal resistance R of the dc potentiometer 22_{DC potentiometer}The approach to infinity causes the measurement loop to form a virtual break, so that the reference electrode is actually separated from the three-electrode system and becomes a single electrode, and the reference electrode 23 which becomes the single electrode is installed in the faraday cage 1 with electromagnetic shielding function, and the faraday cage can block the polarization current I in the electrolyte environment_Pole(s)And stray current I_{Hetero compound}Enters the inner space of the cage through the electrolyte passage, so that polarized current existsI_Pole(s)Formation of E_{2 ginseng-anode}From stray currents I_{Hetero compound}Formation of E_{3 Ginseng and stray}Nor in the present measurement system.

From the above analysis, it can be seen that (I) is obtained by combining the DC potentiometer 22 and the Faraday cage 1_Pole(s)+I_Measuring+I_{Hetero compound}) ×R_u、E_{2 ginseng-cathode}、E_{3 ginseng-cathode}、E_{2 ginseng-anode}、E_{3 Ginseng and stray}Seven interference factors which can appear when the direct current voltmeter is used cannot appear in the measurement reading of the direct current potential difference meter 22 of the novel measurement system, and the measurement value of the direct current potential difference meter 22 is E_{1 steel}+E_{2 steel}+E_{3 steel}－E_{1 Ginseng radix}。

Temperature inside a Faraday cage&The pH probe 33 is not influenced by various stray currents I in the environment_{Hetero compound}And a polarization current I_Pole(s)The interference and the measurement accuracy are ensured, and the measurement result is corrected and calculated according to the relevant electrochemical formula by combining the measurement results of the interference and the measurement accuracy, so that the real potential value E on the steel member 6 can be obtained_Steel＝E_{1 steel}+E_{2 steel}+E_{3 steel}. Thus according to the DC potentiometer 22 and temperature&The measured result of the pH meter 32 can be calculated to obtain the accurate steel material potential E according to the relevant electrochemical formula_Steel。

The utility model discloses a design one kind and be applied to the Faraday cage of electrolyte environment to place steel member 6 in the outside of Faraday cage 1, reference electrode 23 and temperature & pH probe 33 are placed in the inside of Faraday cage 1, and measure the potential difference data in the closed circuit that steel member 6 and reference electrode 23 formed through direct current potential difference meter 22, cooperate temperature & pH probe 33 and temperature & pH meter 32 to measure simultaneously; therefore, the Faraday cage 1 can play a role in shielding electromagnetic interference outside the cage during measurement, and the potential of the steel member 6 can be accurately calculated by combining measurement data.

Obviously, the above embodiments of the present invention are only examples for clearly illustrating the technical solution of the present invention, and are not limitations to the specific embodiments of the present invention, such as the system is also suitable for cathodic protection of steel materials in electrolyte environment, and can even be extended to cathodic protection of other metal materials in electrolyte or electrolyte environment. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A steel member potential measurement system is characterized by comprising a steel member (6), a Faraday cage (1), a direct current potential difference meter (22), a reference electrode (23), a temperature and pH probe (33) and a temperature and pH meter (32); the steel component (6) is arranged outside the Faraday cage (1), and the reference electrode (23) is arranged inside the Faraday cage (1); the steel component (6), the direct current potential difference meter (22) and the reference electrode (23) are connected through leads to form a closed loop circuit; a temperature and pH probe (33) is further arranged inside the Faraday cage (1), and the temperature and pH probe (33) is connected with a temperature and pH meter (32) through a lead; the Faraday cage (1) is used for shielding electromagnetism outside the cage from interfering a reference electrode (23) and a temperature and pH probe (33) in the cage.

2. A steel member potential measuring system as claimed in claim 1, wherein the faraday cage (1) comprises a three layer structure of an outer metal gauze (5), a cage body (2) and an inner metal gauze (4); the outer metal gauze (5) is arranged on the outer wall of the cage body (2), and the inner metal gauze (4) is arranged on the inner wall of the cage body (2); the cage body (2) is made of non-conductive non-metal materials, and the inner metal gauze (4) and the outer metal gauze (5) are made of metal materials with strong conductivity.

3. A steel member potential measuring system according to claim 2, characterised in that the inner (4) and outer (5) metallic screens are separated by a cage (2) and do not touch each other; the inner metal gauze (4) and the outer metal gauze (5) are not contacted with other conductive materials.

4. A steel member potential measuring system as claimed in claim 3, wherein holes (3) are provided in the cage body (2), and apertures are provided in the inner (4) and outer (5) metal screens, the holes (3) and apertures ensuring free ingress or egress of electrolyte into or out of the Faraday cage (1).

5. A steel member potential measuring system according to claim 4, characterized in that the inner side of the inner metal gauze (4), the outer side of the outer metal gauze (5), is provided with a protective layer; the protective layer is made of non-conductive materials and is provided with holes.

6. A steel member potential measuring system according to claim 5, characterized in that said inner metal gauze (4) and outer metal gauze (5) are provided with more than two layers.

7. A steel member potential measuring system according to any of claims 2-6, characterized in that both the inner (4) and outer (5) metal screens are in fact grounded.

8. A steel member potential measuring system according to any of claims 1-6, characterized in that the DC potentiometer (22) is designed on the principle of adjustable balance with a measuring accuracy below 1 mV.

9. A steel member potential measuring system according to any of claims 1-6, characterized in that the steel member (6), Faraday cage (1), reference electrode (23) and temperature & pH probe (33) are completely immersed in an electrolyte environment.