CN114636663A - High-flux multi-channel galvanic corrosion instrument - Google Patents
High-flux multi-channel galvanic corrosion instrument Download PDFInfo
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Abstract
The invention belongs to the technical field of galvanic corrosion test, and particularly relates to a multi-channel galvanic corrosion instrument which is used as a small-sized, light-weight, low-power-consumption, noise-resistant and anti-interference acquisition unit, has the function of continuous power-off test, can work for a long time in the field by configuring a battery with an ultra-long standby state, is based on the zero-resistance current and voltage follower principle, measures, records and rapidly uploads a large amount of galvanic potential and current test data in real time, and obtains the change rules of a plurality of groups of couple potentials and currents through an upper computer so as to rapidly compare and analyze the galvanic current change rules of different couple systems and realize the matching evaluation of a plurality of groups of metal couples; the galvanic corrosion tests of a large number of metal couple pairs under various indoor and outdoor different environmental conditions can be simultaneously carried out, the rapid evaluation of the galvanic corrosion performance of the large number of couple pairs is realized, and the manpower and the time are saved for the material selection of the structure.
Description
The technical field is as follows:
the invention belongs to the technical field of galvanic corrosion tests, and particularly relates to a multi-channel galvanic corrosion instrument which can measure and record galvanic corrosion potential and current among dissimilar metal materials, transmit electrochemical characteristic information in a large amount and quickly and draw a map.
Background art:
galvanic corrosion belongs to local corrosion, also called contact corrosion, and refers to a phenomenon that when two or more different metal materials are contacted with each other in a conductive medium, a corrosion cell is formed due to different electrode potentials, so that the dissolution rate of the metal with a lower potential is increased, and the dissolution rate of the metal with a higher potential is decreased. In order to effectively control galvanic corrosion, a large number of studies are carried out by domestic and foreign scholars, starting from testing electrode potentials of different metal materials, obtaining the galvanic sequence of various materials in a specific environment, exploring various factors influencing the galvanic corrosion behavior, including temperature, distance between couple pairs, cathode-anode area ratio and the like, and providing important basis for controlling galvanic corrosion. The method for testing the galvanic potential and the galvanic current reported in the last 70 th century combines a weight loss method and a polarization curve test, researches the galvanic corrosion behavior, can reflect the degree and the rule of galvanic corrosion from a dynamics perspective, can be used for evaluating the contact corrosion resistance of dissimilar metal materials when contacting in a certain corrosion medium, and plays an important role in material selection design. The galvanic current is initially measured by a zero resistance current meter as shown in fig. 1, and the potential difference between the two electrodes is made zero by adjusting the voltage or resistance, at this time, the current measured by the ammeter is the galvanic current. The disadvantage is that when the circuit is not balanced, the couple pair metal material is polarized, incorrect couple current value occurs or longer recovery time is required. In view of this, operational amplifiers are used to automatically adjust the loop resistance so that the measurement of the galvanic current is continuous, accurate and reliable. On the basis, the galvanic corrosion instrument is produced and used for measuring galvanic corrosion. The galvanic corrosion meter which is originally applied to a laboratory can detect zero resistance current (galvanic current) within the current range of 20 muA-200 mA, but the measuring range, the measured galvanic potential and the natural corrosion potential need to be manually or automatically switched according to the change of a measuring system, and data cannot be automatically recorded, so that great inconvenience is brought to measurement. In addition, the external dimension is 32X 30X 13cm, the net weight is 3Kg, and the method is not convenient for field test. With the development of electronic and computer skills, a galvanic corrosion instrument, even a multi-channel galvanic corrosion measuring device, capable of automatically switching ranges, collecting and drawing curves is available. For example, the multichannel galvanic corrosion measuring device disclosed in chinese patent 201110358680.0, based on the SOC processor, can independently perform programmable control of a galvanic corrosion test process of a metal material, acquisition and storage of galvanic corrosion data, and display and query of a measurement state, is used for measuring galvanic corrosion potentials and galvanic corrosion currents between dissimilar metal materials in different indoor and outdoor environments, and solves technical problems of a galvanic corrosion measuring device in aspects of a control method, signal conditioning, noise interference, and the like. However, the device has 20 channels, the power consumption is large, a power supply is required for field measurement, the device is inconvenient to move, the measurement accuracy of the current is not high, the minimum value is 10 muA, and the fastest sampling frequency is 100 Hz. Subsequently, a CST508 multi-channel galvanic corrosion tester developed by China university of science and technology corrosion and protection research institute adopts a voltage follower circuit and a zero resistance ammeter circuit with high input impedance, a high-reliability industrial control chip and a high-precision data converter ADS1211, and is internally provided with a second-order low-pass filter which can effectively eliminate high-frequency noise from entering a measuring unit and an EMI filter which can prevent surge voltage from causing impact damage; the 16 channels can simultaneously measure 8 electric potentials and 8 current signals (200 mA-200 nA), the current range (total 7 grades) is automatically switched, the data acquisition rate is 0.01 Hz-1 KHz, the data acquisition rate is set through upper computer software controlled by an isolated RS232 serial port, the reliability is improved by adopting firmware for watchdog control, and after a fault occurs, the program can automatically recover to run; the size is 36 multiplied by 26 multiplied by 14cm, and the weight is 7 Kg; the humidity of the working environment is not more than 80%. In addition, a galvanic corrosion/electrochemical noise measuring instrument and an electrochemical workstation can also realize continuous collection of galvanic potential and current, and the parameters are the same as above. However, the above instruments cannot work in an environment with humidity greater than 80%, have large power consumption, volume and weight, are not suitable for long-time field work, and cannot transmit data remotely or in large quantities quickly. Therefore, a high-flux multi-channel galvanic corrosion instrument with low power consumption, small volume and light weight is researched and designed, galvanic corrosion potentials and currents among multiple groups of dissimilar metal materials are rapidly measured and recorded, electrochemical characteristic information is transmitted in a large quantity and rapidly, a map is drawn, and the positive social benefits are achieved.
The invention content is as follows:
the invention aims to overcome the defects in the prior art, and seeks to design a high-throughput multi-channel galvanic corrosion instrument to realize the evaluation and research of the galvanic corrosion performance of dissimilar metal materials indoors and outdoors based on the matching evaluation of a plurality of groups of metal couple pairs.
In order to achieve the above purpose, the appearance structure of the high-flux multi-channel galvanic corrosion instrument (725-CT4 type multi-channel galvanic corrosion instrument) related by the invention is shown in FIG. 2, and the shell is made of aluminum alloy with the function of shielding electromagnetic signals of an electric field; the internal structure is as shown in fig. 3, and comprises 4 completely electrically isolated channels, each channel consists of an input electrode and a front-end analog signal processing part, and a central processing unit is respectively connected with the front-end analog signal processing part, a wireless communication module, a USB communication interface and a data storage module through signal wires; the power management module is respectively connected with the front-end analog signal processing part, the wireless communication module, the central processing unit and the data storage module; each channel independently carries out galvanic potential and current test or simultaneously carries out self-corrosion potential test on two samples, the sampling frequency is 0.01 Hz-10 KHz, wherein the input electrode is a three-electrode system and is respectively a working electrode WE, a counter electrode CE and a reference electrode RE; the lithium battery is a standby power supply.
The front-end analog signal processing part related to the invention is shown in fig. 4 and comprises a zero resistance current meter (ZRA) current-voltage circuit, a high-order low-pass filter 1, an ADC1 converter, an isolation power supply, a high-input impedance circuit, a high-order low-pass filter 2, an ADC2 converter, a communication isolation module and a synchronous control module, wherein the ZRA current-voltage circuit is a current-voltage conversion circuit, as shown in fig. 5, an amplifier A1 adopts a 500MHz ultralow bias current LTC6268 type operational amplifier model, has a voltage swing of 400V/mus, and has extremely low input capacitance, current noise, voltage noise and rail-to-rail output; the high-order low-pass filter 1 and the high-order low-pass filter 2 are both high-order low-pass activeFilter with input impedance greater than 1012Omega, the two are combined, can realize the high-speed large-gain measurement with the attenuation of the cut-off band above-100 dB and the sampling frequency of 10KHz, achieves the purpose of high attenuation amount or fast attenuation rise, effectively improves the signal-to-noise ratio, ensures the accuracy of small current, uses a high-order filter as a low-pass filter, and has high filter quality factor value (Q value) and high gating property; the ADC1 converter and the ADC2 converter are both analog-to-digital converters as shown in fig. 6, and have a synchronous conversion function, where the converted reference voltage is 2.5V, and the signal input is ± 2.5V; the isolation power supply outputs the power supply from one side to the other side in an electromagnetic mode, the input loop and the output loop are not directly electrically connected, the input loop and the output loop are insulated in a high-resistance state, and no current loop exists, so that channels are completely electrically isolated and do not interfere with each other; high input impedance circuit as shown in fig. 7, the LTC6268 type high input impedance is used to convert the electrode potential into a low impedance output circuit with an input resistance greater than 1012Omega, the input capacitance is less than 100fF, and the common mode rejection is greater than 72 dB; the communication isolation module is
The digital isolation integrated circuit adopts an SPI serial peripheral interface as a communication mode, a CS chip selection signal is a selection signal, SCK serial clock pulse is a synchronous clock signal, data is prepared at the rising edge of SCK, data is read at the falling edge, and the communication isolation module isolates the communication between the ADC2 converter and the synchronous control module, so that high-speed communication can be realized.
The MOSI (Master output slave input signal line) of the CPU related by the invention is that the master: the command of the central processing unit is input to the slave in a serial mode: the converter comprises an ADC1 converter and an ADC2 converter, and the MISO (master input and slave output signal) of the central processing unit transmits data of the ADC1 converter and the ADC2 converter of the slave to the central processing unit in a serial mode.
When the ADC1 converter and the ADC2 converter according to the present invention use frequencies, the high-order low-pass filter 1 and the high-order low-pass filter 2 cut frequencies at least 2 times higher than the frequencies, thereby avoiding aliasing of signals in the passband.
When the high-flux multichannel galvanic corrosion instrument related to the invention is used, as shown in figure 8, a plurality of multichannel galvanic corrosion instruments form a data acquisition part, each multichannel galvanic corrosion instrument is an acquisition unit and is connected with a data high-flux processing part through a data high-speed transmission part, the data high-flux processing part comprises an upper computer (a computer or a notebook computer) and software and a data transmission module thereof, the data transmission adopts wireless or wired multipoint collection and processing, including wireless network or Bluetooth connection, and wired multipoint expansion connection of USB (universal serial bus) of 3.0 or more in high-speed transmission, the upper computer can manage each acquisition unit, has the functions of parameter configuration, curve display, historical data query and data derivation, the software of the upper computer is convenient to expand, and can expand acquisition units with different models and specifications according to practical application, the data are uploaded to the upper computer in real time by the wireless communication module in the acquisition unit, the acquisition quantity is not limited, the acquisition unit independently sets acquisition intervals and acquisition modes, the acquisition unit is provided with a standby battery and a power management module, the power supply time of the standby battery is more than 2 hours, and the battery which is in an overlong standby state is connected during field work so as to work for a long time.
Compared with the prior art, the acquisition units have small volume, light weight, low power consumption, noise and interference resistance and continuous power-off test functions, a battery with an ultra-long standby state can work in the field for a long time, a plurality of acquisition units are based on the zero-resistance current and voltage follower principle, measure, record and upload a large amount of galvanic couple potential and current test data in real time and rapidly, and a plurality of groups of galvanic couple potential and current change rules are obtained through an upper computer, so that the galvanic couple current change rules of different galvanic couple systems can be compared and analyzed rapidly, and the matching evaluation of a plurality of groups of metal galvanic couple pairs can be realized; the galvanic corrosion tests of a large number of metal couple pairs under various indoor and outdoor different environmental conditions can be simultaneously carried out, the rapid evaluation of the galvanic corrosion performance of the large number of couple pairs is realized, and the manpower and the time are saved for the material selection of the structure.
Description of the drawings:
fig. 1 is a basic circuit diagram of a zero resistance current meter according to the background art of the present invention.
Fig. 2 is a schematic view of the appearance structure of the present invention.
Fig. 3 is a schematic diagram of the internal structure of the present invention.
Fig. 4 is a schematic view of the structural principle of the channel according to the present invention.
Fig. 5 is a schematic diagram of a ZRA current-voltage circuit according to the present invention.
Fig. 6 is a schematic diagram of an analog-to-digital converter according to the present invention.
Fig. 7 is a schematic diagram of a high input impedance circuit according to the present invention.
Fig. 8 is a schematic view of the usage state of the present invention.
Fig. 9 is a schematic view of a test site according to embodiment 2 of the present invention.
Fig. 10 is a schematic view of a use state of embodiment 3 of the present invention.
The specific implementation mode is as follows:
the invention is further described below by way of an embodiment example in conjunction with the accompanying drawings.
Example 1:
the high-throughput multi-channel galvanic corrosion instrument related to the embodiment has the advantages that the size of the shell is 20 multiplied by 12 multiplied by 5cm, the weight is 200g, the sealing and the water proofing are realized, the volume is small, the weight is light, and the carrying to field work is convenient; the signal input and processing part comprises 4 channels, each channel consists of an input electrode 1 and a front-end analog signal processing part 2, and the central processor 4 is respectively connected with the front-end analog signal processing part 2, the wireless communication module 3, the USB communication interface 5 and the data storage module 8 through a signal wire 9; the USB communication interface 5 is connected with a lithium battery 6 through a power line 10, the lithium battery 6 is connected with a power management module 7, and the power management module 7 is respectively connected with the front-end analog signal processing part 2, the wireless communication module 3, the central processing unit 4 and the data storage module 8; the front-end analog signal processing part 2 comprises a ZRA current-voltage loop, a high-order low-pass filter 1, an ADC1 converter, an isolation power supply, a high-input impedance circuit, a high-order low-pass filter 2, an ADC2 converter, a communication isolation module and a synchronous control module, wherein the ZRA current-voltage loop is connected with the high-order low-pass filter 1, the high-order low-pass filter 1 is connected with the ADC1 converter, the ADC1 converter is connected with the isolation power supply, the high-input impedance circuit is connected with the high-order low-pass filter 2, the high-order low-pass filter 2 is connected with the ADC2 converter and the ADC2 converter is connected with the communication isolation module, and the synchronous control module is respectively connected with the ADC1 converter and the ADC2 converter.
Example 2:
when the high-throughput multichannel galvanic corrosion instrument related to the embodiment is used, as shown in fig. 9, 5 multichannel galvanic corrosion instruments are connected to a computer by a 3.0USB concentrator in a wired connection manner, and 20 groups of couple-pair galvanic corrosion potentials and currents are independently and continuously acquired for 30 days, during which time, an acquisition unit uploads data to the computer in real time through a USB port, a curve is drawn, and power is supplied through a USB port; when the condition of sudden power failure occurs, the lithium battery in the acquisition unit is started to supply power, and data acquisition is ensured to be uninterrupted.
Example 3:
the embodiment relates to a high-flux multichannel galvanic corrosion instrument, as shown in fig. 10, a wireless router is adopted to connect 5 multichannel galvanic corrosion instruments located in a Qingdao laboratory, 3 multichannel galvanic corrosion instruments located in a third-generation testing station (field test) and 2 multichannel galvanic corrosion instruments located in a Qingdao laboratory on a computer in a wireless connection mode, and meanwhile, 40 groups of couple pair galvanic corrosion potentials and currents are independently and continuously acquired for 90 days, during the period, an acquisition unit uploads data to the computer in real time through a wireless network to draw a curve, an acquisition unit located in the Qingdao laboratory supplies power through a USB port, and acquisition units located in the third-generation testing station and the Qingdao laboratory supply power through a mobile power supply; when the condition of sudden power failure is met, the lithium battery in the acquisition unit is started to supply power, and data acquisition is guaranteed to be uninterrupted.
Claims (9)
1. A high-flux multi-channel galvanic corrosion instrument is characterized in that a shell is made of aluminum alloy; the internal structure comprises 4 completely electrically isolated channels, each channel consists of an input electrode and a front-end analog signal processing part, and the central processing unit is respectively connected with the front-end analog signal processing part, the wireless communication module, the USB communication interface and the data storage module through signal wires; through the power cord, USB communication interface is connected with the lithium cell, and the lithium cell is connected with power management module, and power management module is connected with front end analog signal processing part, wireless communication module, central processing unit and data storage module respectively.
2. The high-throughput multi-channel galvanic corrosion instrument according to claim 1, wherein each channel independently performs galvanic potential and current tests or self-corrosion potential tests of two samples at the same time, and the sampling frequency is 0.01Hz to 10 KHz.
3. The high-throughput multichannel galvanic corrosion meter according to claim 1 or 2, wherein the input electrode is a three-electrode system, i.e. a working electrode WE, a counter electrode CE and a reference electrode RE.
4. The high-throughput multichannel galvanic corrosion instrument as claimed in claim 1 or 2, wherein the front-end analog signal processing part is composed of a ZRA current-voltage circuit, a high-order low-pass filter 1, an ADC1 converter, an isolation power supply, a high-input impedance circuit, a high-order low-pass filter 2, an ADC2 converter, a communication isolation module and a synchronization control module, the ZRA current-voltage circuit is connected with the high-order low-pass filter 1, the high-order low-pass filter 1 is connected with the ADC1 converter, the ADC1 converter is connected with the isolation power supply, the high-input impedance circuit is connected with the high-order low-pass filter 2, the high-order low-pass filter 2 is connected with the ADC2 converter, the ADC2 converter is connected with the communication isolation module, and the synchronization control module is connected with the ADC1 converter and the ADC2 converter respectively; wherein, the ZRA current-voltage loop is a current-voltage conversion circuit, the amplifier A1 adopts a 500MHz ultralow bias current LTC6268 type operational amplifier model, and the voltage swing is 400V/mus; the high-order low-pass filter 1 and the high-order low-pass filter 2 are both high-order low-pass active filters, and the input impedance is more than 1012Omega, the two are combined to realize high-speed large gain measurement with more than-100 dB of cut-off band attenuation and 10KHz of sampling frequency; the ADC1 converter and the ADC2 converter are both analog-to-digital converters,the synchronous conversion function is realized, the converted reference voltage is 2.5V, and the signal input is +/-2.5V; the isolation power supply outputs the power supply from one side to the other side in an electromagnetic mode, the input loop and the output loop are not directly electrically connected, the isolation power supply is insulated in a high-resistance state, and a current loop is not provided, so that channels are completely electrically isolated; the high input impedance circuit utilizes LTC6268 type high input impedance to convert electrode potential into low impedance output circuit, and the input resistance is more than 1012Omega, the input capacitance is less than 100fF, and the common mode rejection is greater than 72 dB; the communication isolation module is
The digital isolation integrated circuit adopts an SPI serial peripheral interface as a communication mode, a CS chip selection signal is a selection signal, SCK serial clock pulse is a synchronous clock signal, data is prepared at the rising edge of SCK, data is read at the falling edge, and the communication isolation module isolates the communication between the ADC2 converter and the synchronous control module.
5. The high-throughput multichannel galvanic corrosion meter according to claim 1 or 2, wherein the lithium battery is a backup power supply.
6. The high throughput multi-channel galvanic corrosion instrument according to claim 4, wherein the MOSI of the CPU is configured to: the command of the central processing unit is input to the slave in a serial mode: ADC1 converter and ADC2 converter; the MISO of the central processor transmits the data of the slave ADC1 converter and ADC2 converter to the central processor in a serial manner.
7. The high-throughput multichannel galvanic corrosion meter according to claim 4, wherein the high-order low-pass filter 1 and the high-order low-pass filter 2 cut more than 2 times of the frequency when the ADC1 converter and the ADC2 converter adopt the frequency.
8. The high-throughput multichannel galvanic corrosion instrument according to claim 6, wherein when in use, a plurality of multichannel galvanic corrosion instruments form a data acquisition part, each multichannel galvanic corrosion instrument is an acquisition unit and is connected with a data high-throughput processing part through a data high-speed transmission part, the data high-throughput processing part comprises an upper computer, software thereof and a data transmission module, the data transmission adopts wireless or wired multipoint collection and processing, including wireless network or Bluetooth connection, and wired multipoint expansion connection of USB (universal serial bus) of 3.0 and above for high-speed transmission, the upper computer can manage each acquisition unit, and has the functions of parameter configuration, curve display, historical data query and data derivation, the software of the upper computer is convenient to expand, the acquisition units of different models and specifications can be expanded according to practical application, and data is uploaded to the upper computer in real time by a wireless communication module in the acquisition units, the collection quantity is not limited, the collection unit is independently provided with collection intervals and collection modes, the standby battery and the power management module are provided, the power supply time of the standby battery is more than 2 hours, and the battery which is in an overlong standby state can be connected to work for a long time in the field work.
9. The high throughput multichannel galvanic corrosion meter according to claim 7, wherein the housing has dimensions of 20 x 12 x 5cm, a weight of 200g, and is sealed and waterproof.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116990219A (en) * | 2023-09-22 | 2023-11-03 | 江苏德励达新材料股份有限公司 | Polyurethane panel stability sampling detection device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116990219A (en) * | 2023-09-22 | 2023-11-03 | 江苏德励达新材料股份有限公司 | Polyurethane panel stability sampling detection device |
| CN116990219B (en) * | 2023-09-22 | 2023-11-24 | 江苏德励达新材料股份有限公司 | Polyurethane panel stability sampling detection device |
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