Companion salt fog deposition rate automatic monitoring apparatus and method

Abstract

Provided are a companion salt fog deposition rate automatic monitoring apparatus and method. The automatic monitoring apparatus comprises a wet candle method-based salt fog deposition rate acquisition unit (3), a single-chip microcomputer, a D / A conversion circuit, and a data acquisition module (18). The data acquisition module (18) acquires a current value and a height change of a solution in a catch basin (7) of the wet candle method-based salt fog deposition rate acquisition unit (3), and then the single-chip microcomputer calculates a salt fog deposition rate, thereby implementing real-time online monitoring of the salt fog deposition rate.

Description

A device and method for automatically monitoring salt spray deposition rate

[0001] The present invention claims priority to a Chinese patent application filed with the Patent Office of China on June 29, 2023, with application number 202310779024.0 and entitled “A device and method for automatically monitoring the deposition rate of accompanying salt mist”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present invention relates to the technical field of environmental monitoring, and in particular to a device and method for automatically monitoring the deposition rate of accompanying salt mist. Background Art

[0003] In atmospheric environments, especially marine atmospheric environments, salt spray is the main factor that causes material corrosion. How to quickly and in real time monitor the salt spray deposition rate in atmospheric environments is a prerequisite for the corrosion protection of metal materials.

[0004] Existing methods for sampling salt spray deposition rates combine dry-slice gauze sampling with laboratory analysis. The sampled gauze is exposed to the atmosphere for a 30-60 day chlorine test cycle. After collecting a sufficient amount of chloride ion deposition, gas chromatography or chemical analysis is used to determine the chloride ion content in the gauze, from which the chloride ion deposition rate is calculated. However, these methods suffer from long test cycles, the inability to achieve real-time online monitoring, and the difficulty in correlating the natural environment with salt spray deposition rates. This poses certain limitations for research on the corrosion mechanisms of metal materials.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide a companion type salt spray deposition rate automatic monitoring device and method to achieve real-time online monitoring of the salt spray deposition rate.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The present invention provides a companion type salt spray deposition rate automatic monitoring device, which comprises: a wet candle method salt spray deposition rate acquisition unit, a single chip microcomputer, a D / A conversion circuit and a data acquisition module;

[0009] The single-chip microcomputer is connected to the D / A conversion circuit, and the D / A conversion circuit is connected to the control electrode of the wet candle method salt spray deposition rate acquisition unit. The single-chip microcomputer is used to send digital signal instructions; the D / A conversion circuit is used to convert the digital signal instructions into analog signal instructions and send them to the wet candle method salt spray deposition rate acquisition unit;

[0010] The data acquisition module is respectively connected to the chloride ion selective electrode of the wet candle method salt spray deposition rate acquisition unit and the single chip microcomputer. The data acquisition module is used to collect the current value and height change output by the wet candle method salt spray deposition rate acquisition unit. The single chip microcomputer is used to calculate the salt spray deposition rate based on the current value and height change.

[0011] Optionally, the data acquisition module includes an I / V conversion circuit, a secondary amplification circuit and an A / D conversion circuit connected in sequence.

[0012] Optionally, the automatic monitoring device further comprises: a device base, a device cover, a temperature and humidity sensor, a lithium battery pack, a switch, an aviation plug and an OLED display module;

[0013] The wet candle method salt mist deposition rate collection unit is fixed on the base of the device, and the gauze used for depositing salt mist in the environment into the solution in the wet candle method salt mist deposition rate collection unit is exposed to the environment through a through hole provided on the upper cover of the device and covered by a metal mesh cover;

[0014] The temperature and humidity sensor is arranged on the upper cover of the device;

[0015] The lithium battery pack is arranged in the base of the device and is connected to the wet candle method salt spray deposition rate acquisition unit and the data acquisition module;

[0016] The switch and the aviation plug are both arranged on the side wall of the device base. The switch is connected to the power output terminal of the lithium battery pack. The aviation plug is connected to the single-chip microcomputer via an RS422 serial port module. The aviation plug is used to connect to external devices.

[0017] The OLED display module is arranged on the upper cover of the device, and the OLED display module is connected to the single chip microcomputer.

[0018] Optionally, the wet candle method salt spray deposition rate collection unit includes: a wet candle, gauze, a capture tank, a chloride ion selective electrode and a liquid level detection module;

[0019] One end of the gauze is wound around the wet candle, and the other end of the gauze is deposited in the solution in the collection tank, and the gauze is used to deposit the salt mist in the environment into the solution;

[0020] One end of the chloride ion selective electrode is inserted into the solution of the capture tank, and the chloride ion selective electrode is used to sense the current value of the solution in the capture tank.

[0021] The liquid level detection module is arranged outside the capture tank, and the liquid level detection module is used to sense the height change of the solution in the capture tank;

[0022] The current value and the height change are used to calculate the salt spray deposition rate.

[0023] Optionally, the capture tank includes a capture tank body and a capture tank cover;

[0024] A sealing ring is provided between the collecting tank body and the collecting tank upper cover;

[0025] The upper cover of the collecting tank is provided with a tapered hole, and the other end of the gauze passes through the tapered hole and is deposited in the solution in the collecting tank body.

[0026] Optionally, the upper cover of the collection tank is further provided with a liquid injection hole, and the liquid injection hole is sealed by a sealing plug.

[0027] Optionally, the formula for calculating the salt spray deposition rate is:

[0028] Among them, S d is the salt spray deposition rate, m t is the mass of chloride ions in the solution in the capture tank at time t, m0 is the initial mass of chloride ions in the solution in the capture tank, A is the exposed surface area of ​​the gauze, I Cl is the current value of the solution in the capture tank, and Δh is the height change of the solution in the capture tank.

[0029] A method for automatically monitoring salt spray deposition rate, comprising the following steps:

[0030] Place the wet candle method salt spray deposition rate acquisition unit in the environment to be tested;

[0031] Real-time acquisition of the current value and height change of the solution in the collection tank of the wet candle method salt spray deposition rate acquisition unit;

[0032] Calculating the logarithm of the chloride ion concentration of the solution in the capture tank according to the current value using a calibration relationship, wherein the calibration relationship is used to characterize the relationship between the current and the logarithm of the chloride ion concentration;

[0033] The salt spray deposition rate is calculated based on the logarithm of the chloride ion concentration and the height change of the solution in the collection tank.

[0034] Optionally, the calibration relationship is: I Cl =0.02848C+0.19822;

[0035] Among them, I Cl is the current value of the solution in the capture tank, and C is the logarithm of the chloride ion concentration.

[0036] Optionally, the formula for calculating the salt spray deposition rate is:

[0037] Among them, S dis the salt spray deposition rate, m t is the mass of chloride ions in the solution in the capture tank at time t, m0 is the initial mass of chloride ions in the solution in the capture tank, A is the exposed surface area of ​​the gauze, I Cl is the current value of the solution in the capture tank, and Δh is the height change of the solution in the capture tank.

[0038] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0039] The present invention discloses a companion-type automatic monitoring device and method for salt spray deposition rate. The automatic monitoring device includes: a wet candle method salt spray deposition rate acquisition unit, a single-chip microcomputer, a D / A conversion circuit, and a data acquisition module. The single-chip microcomputer is connected to the D / A conversion circuit, which is connected to a control electrode of the wet candle method salt spray deposition rate acquisition unit. The single-chip microcomputer is configured to send digital signal instructions. The D / A conversion circuit is configured to convert the digital signal instructions into analog signal instructions and send them to the wet candle method salt spray deposition rate acquisition unit. The data acquisition module is connected to the chloride ion selective electrode of the wet candle method salt spray deposition rate acquisition unit. The data acquisition module is configured to collect the current value and height change output by the wet candle method salt spray deposition rate acquisition unit. The single-chip microcomputer is configured to calculate the salt spray deposition rate based on the current value and height change. The present invention uses the data acquisition module to collect the current value and height change of the solution in the capture tank of the wet candle method salt spray deposition rate acquisition unit, and then calculates the salt spray deposition rate based on the single-chip microcomputer, thereby achieving real-time online monitoring of the salt spray deposition rate.

[0040] Figures in the specification

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] FIG1 is a schematic structural diagram of an accompanying salt spray deposition rate automatic monitoring device provided by an embodiment of the present invention;

[0043] FIG2 is a schematic structural diagram of a salt spray deposition rate acquisition unit using a wet candle method according to an embodiment of the present invention;

[0044] FIG3 is an overall block diagram of an accompanying salt spray deposition rate automatic monitoring device provided by an embodiment of the present invention;

[0045] FIG4 is a functional block diagram of a data acquisition module provided by an embodiment of the present invention;

[0046] 5 is a schematic diagram of a D / A conversion circuit according to an embodiment of the present invention;

[0047] FIG6 is a schematic diagram of an I / V conversion circuit according to an embodiment of the present invention;

[0048] FIG7 is a schematic diagram of a secondary amplifier circuit according to an embodiment of the present invention;

[0049] FIG8 is a schematic diagram of an A / D conversion circuit according to an embodiment of the present invention;

[0050] FIG9 is a schematic diagram of a calibration result provided by an embodiment of the present invention.

[0051] Explanation of the accompanying drawings: 1 device cover, 2 temperature and humidity sensor, 3 wet candle, 4 sealing plug, 5 capture tank cover, 6 sealing ring, 7 capture tank, 8 chloride ion selective electrode, 9 liquid level monitoring module, 10M3×6 screw, 11 washer, 12 lithium battery module, 13 device base, 14M4×15 screw, 15 gauze, 16 switch, 17 aviation plug, 18 data acquisition module, 19M2.5×5 pan head screw, 20OLED display module. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0053] The purpose of the present invention is to provide a companion type salt spray deposition rate automatic monitoring device and method to achieve real-time online monitoring of the salt spray deposition rate.

[0054] The embodiments of the present invention are described in further detail below with reference to the accompanying drawings.

[0055] The accompanying salt spray deposition rate automatic monitoring device of the present invention, as shown in Figure 1, comprises a device cover 1, a temperature and humidity sensor 2, a wet candle method salt spray deposition rate acquisition unit 3, an OLED display module 20, a data acquisition module 18, a lithium battery pack 12, a device base 13, a switch 16, and an air plug 17. The wet candle method salt spray deposition rate acquisition unit 3 is fixed to the device base 13 using M3×M3×6 screws 10. The wet candle 3 is wrapped with gauze and passed through the exposed acquisition portion of the device cover 1, which is then covered by a metal mesh cover. The temperature and humidity sensor 2 is fixed to the device cover 1 to monitor the temperature and humidity of the wet candle portion in real time. The OLED display module 20 is connected to the device cover 1 and sealed with epoxy resin. The data acquisition module 18 is connected to the device base 13 and secures the lithium battery pack 12 to the device base 13 via fixing pins. The air plug 17 and switch 16 are fixed to the device base 13 via threaded connections.

[0056] Referring to Figure 2, the wet candle method salt spray deposition rate collection system includes: a wet candle 3, gauze 15, a collection tank cover 5, a sealing ring 6, a collection tank 7, a chloride ion selective electrode 8, and a liquid level detection module 9. The gauze is wrapped around the wet candle, with one end fixed and the other free. The free end is deposited in the solution in the collection tank. The gauze deposits salt spray into the solution, and the electrode senses changes in the current value in the solution in real time. The collection tank cover has a tapered hole to facilitate the free fall of the gauze and the deposition of salt spray. The collection tank is filled with sodium chloride solution (a mixture of sodium chloride and glycerol with a sodium chloride concentration of 0.3 to 0.5 mg / ml). When salt spray is deposited into the collection tank, the current value in the collection tank changes. The liquid level detection module is directly installed outside the collection tank, enabling contactless monitoring. By monitoring the volatilization state of the solution in the collection tank in real time, an alarm is issued when the solution content falls below a set threshold. Solution can be added through the small hole in the collection tank cover.

[0057] Referring to FIG3 , the data acquisition and processing analysis portion of the accompanying salt spray deposition rate automatic monitoring device of the present invention (i.e., the data acquisition circuit in FIG3 ) mainly includes an analog / digital conversion portion (i.e., a D / A conversion circuit), a single-chip microcomputer portion (i.e., a single-chip microcomputer), a signal acquisition and upload portion (i.e., a data acquisition module), a clock unit, a data storage unit, and a power supply system. As shown in FIG4 , the detection method is to generate an excitation voltage signal required by the electrode system through the single-chip microcomputer and the D / A conversion circuit (corresponding to the D / A module in FIG4 ), apply the voltage signal to the electrode module, and then the chloride ion selective electrode generates a corresponding detection signal. After the signal generated by the electrode is collected by the signal processing module, it is converted into a digital signal by the A / D conversion circuit (corresponding to the A / D module in FIG4 ), collected by the single-chip microcomputer system, and saved in the Flash module. When uploading is required, it is uploaded to the computer via the RS422 interface. The OLED display module only displays necessary information during the system operation.

[0058] Referring to the D / A conversion circuit shown in FIG5 , after the DAC8831 communicates with the microcontroller via SPI, the microcontroller sends a digital signal instruction, which is converted into an analog signal by the DAC, and then outputted through the DAC_out of the OP277 and applied to the electrode.

[0059] Referring to the I / V conversion circuit described in Figure 6, the working electrode is connected to the left side of the resistor R41. After I / V conversion, the output voltage is V0=I0*R40. After using the resistor R40 for I / V conversion, R40 will introduce stray capacitance. Therefore, a second-order low-pass filter is designed to eliminate the influence of detection signal noise and output voltage VIN+.

[0060] Referring to the two-stage amplifier circuit described in Figure 7, INA114 is used for design, and its gain multiple is A=1+50KΩ / R44. After testing, the output current after salt spray deposition is generally in the uA level. After the previous stage I / V conversion, the output voltage VIN+ is in the mV level. The gain in the second-stage amplifier circuit is designed to be A=10, and R44=5.6KΩ.

[0061] Referring to the AD7705 analog-to-digital conversion circuit shown in Figure 8, the converted digital signal is transmitted to the microcontroller via SPI communication. The microcontroller converts the received digital signal to obtain the corresponding current value. By calibrating sodium chloride mixed solutions with various concentrations, a salt spray deposition rate model curve is obtained. By programming the model into the microcontroller system, real-time online monitoring of the salt spray deposition rate can be achieved.

[0062] In the circuit, R38, R39, R40, R41, R42, and R44 need to be low-temperature drift resistors with a temperature coefficient below 1 ppm and an accuracy of more than 1%, which can improve the accuracy of the analog acquisition circuit.

[0063] The device was calibrated using 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 The calibration was performed with a sodium chloride solution having a concentration of mol / L. The calibration data is shown in FIG9 , and the calibration result is 1 Cl =0.02848C+0.19822, where C is the logarithm of the chloride ion concentration, i.e. C=lg(chloride ion concentration).

[0064] The volume of the solution in the capture tank is V=36cm 3 , area S = 12 cm 2 , height h = 3 cm, the diameter of the wet candle is 1.5 cm, and the height of the exposed surface is 2 cm. The area of ​​the exposed surface can be calculated to be A = 3π.

[0065] The change in liquid level measured by the liquid level detection module is Δh, and the mass of chloride ions at a certain moment can be calculated. The calculated deposition rate is: Where t is time (days), m0 is the mass of chloride ions in the prefabricated sodium chloride and glycerol mixed solution in the capture tank (mg),

[0066] The real-time online monitoring method of the accompanying salt spray deposition rate automatic monitoring and detection device has the following specific steps:

[0067] Place the wet candle method salt spray deposition rate acquisition unit in the environment to be tested;

[0068] Real-time acquisition of the current value and height change of the solution in the collection tank of the wet candle method salt spray deposition rate acquisition unit;

[0069] Calculating the logarithm of the chloride ion concentration of the solution in the capture tank according to the current value using a calibration relationship, wherein the calibration relationship is used to characterize the relationship between the current and the logarithm of the chloride ion concentration;

[0070] The salt spray deposition rate is calculated based on the logarithm of the chloride ion concentration and the height change of the solution in the collection tank.

[0071] The wet candle method salt spray deposition rate acquisition unit is placed in the test environment, specifically including:

[0072] (1) Install the prepared wet candle method salt spray deposition rate acquisition unit on the device base and fix it with M4×15 screws 14;

[0073] (2) Install the aviation plug and switch to the base of the device;

[0074] (3) Install the lithium battery and circuit board on the base of the device and fix the circuit board and lithium battery with M2.5×5 pan head screws 19;

[0075] (4) Install the OLED display module and the temperature and humidity sensor module on the device cover and seal them;

[0076] (5) Connect the connectors of all modules to the circuit board according to the design, and use M4 screws to fix the device cover and base.

[0077] Among them, key information such as real-time chloride ion concentration, battery power and mixed solution capacity can be seen on the OLED display module; through the RS422 data line connecting the transmission interface of the device, instructions are issued through the host computer software to upload the data stored in the Flash to the computer in .txt format. The data information includes: time, chloride ion deposition amount, concentration, temperature, humidity and other key information.

[0078] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0079] 1. This invention utilizes a wet candle method salt spray deposition rate acquisition module and a data acquisition and upload module to enable real-time online monitoring of atmospheric salt spray concentration. It can record the salt spray deposition rate in real time, providing long-term data for structural corrosion studies.

[0080] 2. The present invention adopts a chloride ion selective electrode, and the chloride ion deposition amount is directly obtained by measuring the change in the electrode current value, thereby calculating the chloride ion deposition rate. No human intervention is required in the measurement of the entire cycle, and efficient, high-precision and fast measurement can be achieved. The long-term recorded data can be transmitted to a computer through the RS422 serial port for specific analysis.

[0081] 3. The real-time monitoring device for salt spray deposition rate of the present invention can perform long-term real-time online monitoring without human intervention in the detection process. The device is small in size and can realize salt spray concentration monitoring in a small space. The device of the present invention is significantly ahead of traditional detection methods and current large-scale monitoring devices that can realize real-time monitoring.

[0082] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all protected by the present invention.

Claims

1. An accompanying salt spray deposition rate automatic monitoring device, characterized in that: The automatic monitoring device comprises: a wet candle method salt spray deposition rate acquisition unit, a single chip microcomputer, a D / A conversion circuit and a data acquisition module; The single-chip microcomputer is connected to the D / A conversion circuit, and the D / A conversion circuit is connected to the control electrode of the wet candle method salt spray deposition rate acquisition unit. The single-chip microcomputer is used to send digital signal instructions; the D / A conversion circuit is used to convert the digital signal instructions into analog signal instructions and send them to the wet candle method salt spray deposition rate acquisition unit; The data acquisition module is respectively connected to the chloride ion selective electrode of the wet candle method salt spray deposition rate acquisition unit and the single chip microcomputer, the data acquisition module is used to collect the current value and height change output by the wet candle method salt spray deposition rate acquisition unit, and the single chip microcomputer is used to calculate the salt spray deposition rate based on the current value and height change.

2. The accompanying salt spray deposition rate automatic monitoring device according to claim 1 is characterized in that: The data acquisition module comprises an I / V conversion circuit, a secondary amplification circuit and an A / D conversion circuit which are connected in sequence.

3. The accompanying salt spray deposition rate automatic monitoring device according to claim 1 is characterized in that: The automatic monitoring device also includes: a device base, a device cover, a temperature and humidity sensor, a lithium battery pack, a switch, an air plug and an OLED display module; The wet candle method salt mist deposition rate collection unit is fixed on the base of the device, and the gauze used for depositing the salt mist in the environment into the solution in the wet candle method salt mist deposition rate collection unit is exposed to the environment through the through hole provided on the upper cover of the device and covered by a metal mesh cover; The temperature and humidity sensor is arranged on the upper cover of the device; The lithium battery pack is arranged in the base of the device and is connected with the wet candle method salt spray deposition rate acquisition unit, the temperature and humidity sensor, the single chip microcomputer, the D / A conversion circuit, the data acquisition module and the OLED display module; The switch and the aviation plug are both arranged on the side wall of the device base, the switch is connected to the power output end of the lithium battery pack, the aviation plug is connected to the single-chip microcomputer via an RS422 serial port module, and the aviation plug is used to connect an external device; The OLED display module is arranged on the upper cover of the device. Connected with the single chip microcomputer.

4. The accompanying salt spray deposition rate automatic monitoring device according to claim 1 is characterized in that: The wet candle method salt spray deposition rate collection unit comprises: a wet candle, gauze, a capture tank, a chloride ion selective electrode and a liquid level detection module; One end of the gauze is wound around the wet candle, and the other end of the gauze is deposited in the solution in the collection tank, and the gauze is used to deposit the salt mist in the environment into the solution; One end of the chloride ion selective electrode is inserted into the solution of the capture tank, and the chloride ion selective electrode is used to sense the current value of the solution in the capture tank; The liquid level detection module is arranged outside the capture tank, and the liquid level detection module is used to sense the height change of the solution in the capture tank; The current value and the height change are used to calculate the salt spray deposition rate.

5. The accompanying salt spray deposition rate automatic monitoring device according to claim 4 is characterized in that: The capture tank comprises a capture tank body and a capture tank upper cover; A sealing ring is provided between the collection tank body and the collection tank upper cover; The upper cover of the collecting tank is provided with a conical hole, and the other end of the gauze passes through the conical hole and is deposited in the solution in the collecting tank body.

6. The accompanying salt spray deposition rate automatic monitoring device according to claim 5 is characterized in that: The upper cover of the collection tank is also provided with a liquid injection hole, and the liquid injection hole is sealed by a sealing plug.

7. The accompanying salt spray deposition rate automatic monitoring device according to claim 1 is characterized in that: The formula for calculating the salt spray deposition rate is: Among them, S d is the salt spray deposition rate, m t is the mass of chloride ions in the solution in the capture tank at time t, m0 is the initial mass of chloride ions in the solution in the capture tank, A is the exposed surface area of ​​the gauze, I Cl To sense the current value of the solution in the capture tank, Δh is the height change of the solution in the capture tank.

8. A method for automatically monitoring the salt spray deposition rate, characterized in that: The automatic monitoring method comprises the following steps: Place the wet candle method salt spray deposition rate acquisition unit in the environment to be tested; Real-time acquisition of the current value and height change of the solution in the collection tank of the wet candle method salt spray deposition rate acquisition unit; According to the current value, the logarithm of the chloride ion concentration of the solution in the capture tank is calculated using a calibration relationship, wherein the calibration relationship is used to characterize the relationship between the current and the logarithm of the chloride ion concentration; The salt spray deposition rate is calculated based on the logarithm of the chloride ion concentration and the height change of the solution in the collection tank.

9. The accompanying salt spray deposition rate automatic monitoring method according to claim 8 is characterized in that: The calibration relationship is: Cl =0.02848C+0.19822; Among them, I Cl is the current value of the solution in the capture cell, and C is the logarithm of the chloride ion concentration.

10. The accompanying salt spray deposition rate automatic monitoring method according to claim 8, characterized in that: The formula for calculating the salt spray deposition rate is: Among them, S d is the salt spray deposition rate, m t is the mass of chloride ions in the solution in the capture tank at time t, m0 is the initial mass of chloride ions in the solution in the capture tank, A is the exposed surface area of ​​the gauze, I Cl To sense the current value of the solution in the capture tank, Δh is the height change of the solution in the capture tank.

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