RU2225594C1 - Meter of corrosion parameters - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: invention refers to nondestructive inspection of objects and can be used to measure parameters of process of metal corrosion in conductive liquid media to diagnose condition of technological equipment and pipe-lines. Meter incorporates sensor-probe, unit of preliminary signal processing, multichannel analog-to-digital converter, microprocessor, energy-independent storage module, liquid-crystal display, keyboard, real time clock, heating element and temperature-sensitive element. Meter case housing functional units and elements is placed in sealed protective box. Energy-independent storage module is detachable and can be connected to meter from outside of case. EFFECT: widened functional potential of meter, expanded temperature range in which meter can operate. 4 cl, 3 dwg

Description

 The invention relates to non-destructive testing of objects and can be used to measure the parameters of the corrosion process of metals in electrically conductive liquid media in order to diagnose the condition of technological equipment and pipelines used for the processing and transportation of liquid electrically conductive media, for example oil.

 The prior art.

 From the patent literature there are known devices containing measuring electrodes connected by current leads to an information processing and control unit connected to an indicator unit, for example, “Device for quality control of anticorrosive coatings on the inner surface of pipelines” (a.s. SU 1509710 A1, 4 G 01 N 27/20, priority 29.06.87, publ. 23.09.89), "Device for non-destructive quality control of pipe walls" (patent RU 2037815 C1, 6 G 01 N 27/20, 27/00, priority 21.12.90, publ. 19.06 .95).

 One of the analogues of the claimed device is an "Electrochemical analyzer of the physical and chemical properties of materials" (patent RU 2112965 C1, 6 G 01 N 27/00, 27/20, priority 10.10.97, publ. 10.06.98), containing a power source, unit information processing and control with a remote control for entering research programs at the input and an indicator unit at the output, as well as measuring electrodes connected to the information processing and control unit.

 The analog device allows reducing analysis time, diagnosing the condition and the possibility of breakdowns, and predicting the operating life of the operated equipment.

 Another analogue of the claimed technical solution is a "Portable data acquisition device" (patent US 5526287, IPC 6 G 01 D 9/00, publ. 1996), containing a sensor - a primary transducer of a physical quantity into an electrical signal, connected by a cable to the electronic preliminary unit signal processing, including a power source, a multiplexer, an analog-to-digital converter and a microprocessor, including a controller, a real-time timer and a storage device.

 The electronic data processing unit is made in a separate housing and can operate independently of the signal processing system (computer). A power source in the form of one or more batteries provides the storage of the measured data in a storage device. The disadvantage of this analogue is the limited resource of continuous operation without replacing the batteries.

 The closest in technical essence, that is, the prototype, is the device described in the invention "Method for registering a mechanical quantity and a registrar for implementing the method" (patent RU 2189565 C2, IPC 7 G 01 D 9/00, priority 30.10.2000, publ. September 20, 2002).

 Common features of the prototype (mechanical quantity recorder) and the claimed device (corrosion parameter meter) is the presence of a sensor - a primary converter of the measured value into an electrical signal (in the inventive device, the sensor is a primary converter of informative values into electrical signals), and an electronic unit including an electrical connector, power source, temperature sensor, signal amplifiers (in the inventive device, the signal preprocessing unit), multiplexer, analog The digital converter (ADC), a microprocessor, a controller comprising, random access memory (RAM) and a real time clock; an electrically programmable non-volatile memory device (in the inventive meter non-volatile memory module), as well as a housing in which interconnected functional units are located. The output of the amplifier-driver is connected to the input of the multiplexer.

 The disadvantage of the prototype is limited functionality due to the fact that the registrar does not have functional completeness, since it pre-accumulates the measured data, namely the mechanical value, time of unregulated loads and temperature. Then, when connecting the recorder via the data acquisition console to the final signal processing system (computer), the transmitted measurement results are processed according to a special program and displayed on the display screen or printer as the final result. In addition, the information necessary for its operation (temperature dependence of the conversion coefficient, the moment of switching on the operating mode of the registrar, etc.) is recorded in the registrar from the final signal processing system through a portable data collection console, therefore the recorder must be operated together with the entire system.

 Another disadvantage of the prototype is the limited service life without replacing the batteries, although the increase in battery life due to power savings is achieved by reducing the frequency of writing data to RAM by initially analyzing and discarding non-informative signals that are considered mechanical noise and are not recorded by the recorder, as well as decreasing the sampling frequency of the ADC.

 In addition, EPEZU allows long-term storage of measured data without the consumption of electrical energy.

 SUMMARY OF THE INVENTION

The problem to be solved by the claimed device is aimed at:
a) expansion of functionality;
b) increase the battery life without replacing the batteries;
c) increasing the temperature range at which the device can operate.

The technical result achieved by the implementation of the invention is:
a) expansion of functionality due to the implementation of several measurement modes (manual and autonomous), indication of the measurement results, the ability to control the measurement process by quickly changing the installation coefficients ( _VA , _VK , K and S) characterizing the electrically conductive medium and measuring electrodes, by changing the time interval between the Tism measurements and changing the time pause before the start of the Tcm measurement, by ensuring continuous monitoring by overwriting the measurement results from RAM ikroprotsessora in a removable, non-volatile memory module and replace it with a new one;
b) increase the battery life without replacing the batteries by reducing power consumption due to power scheduling (distributed power system) and the introduction of a "sleep" mode, when the function blocks are active only during the next measurement interval, and are automatically turned off in the pauses between measurements, and through the use of non-volatile memory module;
c) an increase in the temperature range at which the device can operate due to thermostating and heating required for the operation of the liquid crystal display and placing the electronic part of the device in a sealed box to protect it from environmental influences.

 To achieve a technical result in a corrosion parameter meter containing a sensor - a primary converter of informative values into electrical signals, a non-volatile memory module and a power source, electrical connector, temperature sensor, signal preprocessing unit, the output of which is connected to the multi-channel analog-to-digital input a converter (MACP) including a multiplexer and an ADC; as well as a microprocessor including a controller, RAM and a real-time timer, according to the invention, the following is provided: a second electrical connector, a power controller, a keyboard, a liquid crystal display, a real-time clock and a heating element are additionally inserted into the housing, the microprocessor being connected by corresponding one-way connections with a signal preprocessing unit, a liquid crystal display, and corresponding two-way communications - with the MACP, keyboard, clock and real time, a temperature sensor, a power controller and the first electrical connector, which is connected in parallel to the digital outputs of the MACP with its information outputs, the second electrical connector is connected via two-way communications to the signal preprocessing unit, the power controller, with its three control outputs, is respectively connected to the first electrical connector, a heating element and a signal preprocessing unit together with a liquid crystal display, a source Itani connected to respective feed temperature sensor inputs, the real time clock, Matzpen, a microprocessor, and power controller; non-volatile memory module connected by two-way connections to the first electrical connector, and the housing with the functional blocks and elements housed in it are placed in a sealed protective box equipped with a third electrical connector, inputs connected via a cable to a sensor - a primary converter of informative values into electrical signals, and outputs - through a cable inside the box with a second electrical connector.

 The primary converter of informative values into electrical signals is made in the form of a probe comprising two sensor electrodes connected to a cable.

 The housing contains two electrical connectors mounted on its front side, and a front panel on which the keyboard field and the LCD panel are located, while the temperature sensor and the heating element are located near the display and have thermal connection with it.

 The sealed protective box is made of high-strength material, such as polystyrene, and consists of a lid and base with an electrical connector on its end side connected to a cable that connects to the second electrical connector of the housing, and has a filler made of a material with low thermal conductivity, such as polystyrene, heaton or isolon, while the cable is located between the base and the filler, and the box is equipped with brackets for installation in suspension.

 Non-volatile memory module is removable with the ability to connect to the first electrical connector on the outside of the housing.

 New distinctive functional blocks and elements of the claimed device: power controller, keyboard, liquid crystal display, real-time clock, heating element, two electrical connectors, sealed protective box.

New functional blocks and elements are connected by the corresponding inputs and outputs to other functional blocks and form new distinctive connections that allow the measurement of corrosion parameters as a function of time, namely: corrosion current I _cor , corrosion rate V _cor and real measurement time.

 The power controller distributes the energy from the power source between the functional units, cyclically applies power to them, and after processing the signal with the appropriate unit, it turns off its power, providing a "sleep" mode, which increases the battery life in the autonomous mode without replacing the battery. In addition, it controls the voltage drop in the batteries in order to prevent unreliable measurement results.

The keyboard is intended for manual control of the measurement process by the operator, for the installation of the programmable coefficients B _a and B _k , the conversion factors K and S, the variable parameters Tism and Tcm, as well as the current time and date, when the device is in stand-alone mode. When checking the performance, in the process of maintenance and calibration, use the keyboard to switch operating modes.

 The liquid crystal display is designed to reproduce the necessary commands and the results of the measurements, as well as the results of monitoring the battery. In the pauses between measurements, the display automatically turns off, which helps save battery power.

 A real-time clock is necessary for recording during the measurement of the current time and setting the time intervals characterizing the measurement process.

 The heating element is located near the liquid crystal display and, together with the temperature sensor, serves to create the necessary temperature regime for its functioning.

 The second and third electrical connectors connect the sensor - the primary converter of informative values into electrical signals to the measuring part of the device inside the case and protective box. In addition, the second electrical connector, when connecting cables or a calibration module to it, transfers the electronic power supply switch to the open state.

A sealed box protects the functional blocks of the device from environmental influences, providing an operating temperature range from -45 ^o С to +55 ^o С.

 The set of distinctive features of the claimed device is not found from the patent and scientific and technical information.

 The inventive device is illustrated by the description and drawings, where figure 1 shows a structural diagram of a meter of corrosion parameters; figure 2 - block diagram of the connection of the memory module with the data processing system (computer).

The photo (figure 3) presents the following:
a) modification of the device for work in the laboratory;
b) modification of the device for work in the field, when the corrosion parameter meter is placed in a sealed protective box;
c) an information reading unit connected to a memory module.

Figure 1 and 2 indicate the following:
1 - sensor-primary converter of informative values into an electrical signal (probe);
2 - probe cable;
3 - case;
4 - the first electrical connector;
5 - signal preprocessing unit;
6 - multichannel analog-to-digital Converter (MACP);
7 - multiplexer;
8 - analog-to-digital Converter (ADC);
9 - microprocessor;
10 - controller;
11 - random access memory (RAM);
12 - real-time timer;
13 - power source;
14 - real time clock;
15 - temperature sensor;
16 - power controller;
17 - keyboard;
18 is a liquid crystal display;
19 - heating element;
20 is a second electrical connector;
21 - non-volatile memory module;
22 - sealed protective box;
23 - the third electrical connector;
24 - cable in a protective box;
25 - block reading information (BSI);
26 - data processing system (computer);
27 is an interface connecting a memory module and BSI;
28 is an interface connecting the BSI and the computer.

 The sensor is a primary Converter of informative values into electrical signals (probe) 1 is connected by cable 2 to the inputs of the third electrical connector 23 and through cable 24 to the inputs of the second electrical connector 20, which is connected by two-way connections to the signal preprocessing unit 5, the output of which is connected to the corresponding input MATsP 6, including multiplexer 7 and ADC 8.

 The microprocessor 9 is connected by corresponding one-way connections to the signal preprocessing unit 5 and the liquid crystal display 18. The corresponding two-way connections are made by the microprocessor 9 with the MACP 6, the keyboard 17, the real-time clock 14, the temperature sensor 15, the power controller 16 and the first electrical connector 4, which information outputs connected in parallel to the digital outputs of the MACP 6.

 The power controller 16, with its three control outputs, is respectively connected to the first electrical connector 4, the heating element 19, and the signal preprocessing unit 5 together with the liquid crystal display 18.

 The power source 13 is connected to the corresponding power inputs of the temperature sensor 15, the real-time clock 14, the MAPC 6, the microprocessor 9, and the power controller 16.

 Non-volatile memory module 21 is connected by two-way connections to the first electrical connector 4 on the outside of the housing 3, which provides quick removal of the memory module 21 and replacing it with a new one.

 The microprocessor 9 includes a controller 10, RAM 11 and a real-time timer 12.

 RAM 11 is used to store intermediate results of indirect calculations. After their recalculation according to a given program, the final measurement results remain in RAM 11, and then are transferred to the memory module 21.

 Overwriting the recorded information from RAM 11 to the non-volatile memory module 21 allows you to permanently save and accumulate measurement data (data packets) without energy consumption and disconnect the memory module 21 from the power source 13 in the intervals between measurements.

 The real-time timer 12 generates clock pulses to synchronize the functional units of the microprocessor 9, control the ADC 8 with the multiplexer 7.

 The controller 10 includes an interface controller, a program memory, data EPEZU.

 The interface controller is designed to control the MACP 6 and the organization of the process of transmitting measurement results to the memory module 21.

 The program memory is used to store control programs that implement the specified algorithm: measurements, calculations, indications and recording of measurement results in the memory module.

 EPEZU data is intended for storing and storing the operator-defined coefficients Ba, Bk, K and S, time parameters Tcm and Tism, as well as the time and date of the start of measurements.

 The possibility of electrical programming of the data EPEZU allows you to control the measurement process by quickly changing the installation coefficients and time intervals characterizing the measurement mode, cleaning the data EPEZU and writing new information to it when changing measurement modes, which extends the functionality of the claimed device.

 The power source 13 contains two small batteries with a total rated voltage of 3V and provides autonomous power supply to the functional blocks.

 The power controller 16 determines the sequence of operation of the functional blocks, cyclically applies voltage to them and provides a sleep mode.

 The first electrical connector 4 is necessary for organizing communication of the microprocessor 9 with the memory module 21 and switching the power supply to the memory module 21 at the time of overwriting the information in it.

 The non-volatile memory module 21 accumulates all measurement results carried out both in manual mode, if it is connected to the device, and offline. Further, as the memory module 21 is filled, it is disconnected from the device and the measurement results (data packets) are copied to the computer, data processing system 26 for further analysis.

 All functional blocks and elements, except for the memory module 21 and the third electrical connector 23, are placed in the housing 3, on the front side of which there are two electrical connectors 4 and 20. On the front panel of the housing 3 are the keyboard field 17 and the LCD panel 18. Near the display 18, a temperature sensor 15 and a heating element 19 are placed to monitor and maintain the required temperature.

 In this modification, the inventive device is used for manual operation in laboratory conditions (photo, option a), while the sensor (probe) 1 is connected via cable 2 to the second electrical connector 20 of the housing 3.

 To work in stand-alone mode and in real conditions near the equipment being diagnosed, for example, a pipeline, the measuring device is placed in an airtight protective box 22 made of high-strength material, such as polystyrene. The protective box 22 consists of a lid and a base, on the front side of which an electrical connector 23 is installed. The base and lid of the box 22 are provided with a filler made of a material with low thermal conductivity, for example, foam, thermon or isolon. For installation in a suspended state, the protective box 22 has brackets fixed around the perimeter of the base.

 A memory module 21 is placed in the protective box 22, which is connected to the first electrical connector 4 located on the front side of the housing 3.

 The third electrical connector 23 through the cable 24, located between the base of the protective box 22 and the filler, is connected to the second electrical connector 20 of the housing 3.

 The sensor (probe) 1 through cable 2 is connected from the outside to the electrical connector 23 of the protective box 22.

 In this modification, the device can be operated around the clock offline with stops for maintenance (photo, option b).

 The inventive device is made on the known element base.

 The operation of the device.

 The principle of the device’s operation is based on the linear polarization method (a synonym for the method of “polarization resistance”).

Indirect measurements of the corrosion current I _cor and the corrosion rate V _{cor by} this method are carried out by measuring the resistance R _{mp of the} interelectrode gap of the probe when a small potential difference (usually not exceeding 20-30 mV) is applied to the electrodes and special computational procedures are implemented.

где В_а, В_к - задаваемые с клавиатуры 17 значения программируемых коэффициентов Тафеля.The value of the corrosion current I _{cor is} obtained as a result of a computational procedure implemented by the device according to the formula

where В _а , В _к are the values of programmable Taffel coefficients set from the keyboard 17.

где К и S - задаваемые с клавиатуры 17 значения пересчетных коэффициентов, учитывающих материал и площадь электродов датчика (зонда) соответственно.Further, the obtained corrosion current is converted by the device into the corrosion rate V _cor in accordance with the formula

where K and S are the values of translation factors specified from the keyboard 17, taking into account the material and the area of the electrodes of the sensor (probe), respectively.

 In practice, current measurement under the influence of a small potential difference on the electrodes is complicated by the fact that there is a double electric layer at the electrode-solution interface, i.e. electric capacity. The presence of capacitance leads to the fact that at the first moment after applying the potential difference to the electrodes, the current value significantly exceeds its value in the stationary mode.

The current value and, accordingly, the corrosion rate depend on the time interval T _cm elapsed since the potential difference was applied to the electrodes and the measurement started.

The capacity of the double electric layer is determined by the electrochemical properties of the electrode-solution system, the nature of the electrolyte, the presence of surface-active substances in the electrolyte, etc., and can vary within wide limits. Correspondingly, the time interval T _cm , which is necessary to obtain the correct values of the current I _cor from several seconds to tens of minutes, also varies widely. In this regard, the device provides for the possibility of programming from the keyboard the values of T _cm - the time interval for specific parameters of the electrode-solution system.

 In addition, the keyboard 17 provides the ability to set the time interval Tiz between adjacent measurements.

 Measurements are carried out as follows.

After turning on the device, the operator must use the keyboard 17 to set the current time and date of the start of measurements, the values of the coefficients В _а , В _к , К and S and the measurement parameters: T _cm - time interval between the voltage supply to the electrodes of sensor 1 and the beginning of measurements and T _meas - time interval between measurements.

 The device has two measurement modes: manual and standalone.

 In manual mode, the measurement result appears only after a command issued by the operator via the keyboard 17. At the same time, the display 18 and the functional blocks of the device are constantly active, only at the time of measurement the keyboard 17 is locked.

In stand-alone mode, measurements are carried out without operator intervention, automatically, at time intervals T _meas .

 In this mode, the display 18 together with the MACP 6, the signal preprocessing unit 5 are active only during the next measurement time interval, and are automatically turned off during the pauses between measurements (sleep mode), which ensures the most efficient use of the power source’s energy and increases battery life of the device.

After the measurement mode has been selected and started by the operator, a small voltage (20-30 mV) is supplied to the electrodes of the sensor 1 through electrical connectors 20 and 23. Then, after a time interval of T _{cm, the} MASP 6 makes measurements, according to the results of which the microprocessor 9 calculates R _mp , I _cor , V _cor and stores them in RAM 11, and the display 18 displays the obtained values. The measurement results from RAM 11 via the interface and through the electrical connector 4 are overwritten in the memory module 21, on which power appears during recording. At the end of the recording, the memory module 21 is again de-energized until the next recording. For each measurement, I _cor , V _cor , date and time of its implementation are remembered. The next measurement is carried out at a given time interval T _meas .

 The temperature sensor 15 is cyclically interrogated and its readings are entered into the microprocessor 9. If the temperature is lower than the set value, then the heating element 19 is turned on through the power controller 16. When the temperature reaches above the set value through the power controller 16, the heating element 19 is turned off.

Thus, the informative signals received from the sensor 1 are supplied via cables 2 and 24 through the electrical connectors 23 and 20 to the signal preprocessing unit 5, where they are amplified, and converted into digital form in the MACP 6. Entering the microprocessor 9, the signals are processed according to a given program, and when the final result is received, they are displayed on the display 18 and stored in the RAM 11. From the RAM 11, the information is overwritten by the corresponding interface that connects the microprocessor 9 and the first electrical connector 4 to the memory module 21. The values of the corrosion current I _cor , the corrosion rate V _cor , the date and time of the measurements (data packet) are recorded and accumulated in the non-volatile memory module 21.

 Upon filling the memory module with 21 data packets, the operator replaces it with a new module to continue the operation of the device.

 Subsequently, the information contained in the memory module 21 is read into the data processing system (computer) 26. For this, the memory module 21 is connected to the computer 26 through the interface 27, the information reading unit 25 through the interface 28. The obtained information is analyzed to determine the development trends of the corrosion process.

Thus, the expansion of the functionality of the device is achieved through
a) the introduction of two measurement modes: manual under the control of the operator and autonomous according to a given program;
b) the ability to control the measurement process by changing the coefficients and time intervals between measurements;
c) continuous monitoring of the corrosion process.

 An increase in the battery life of the device without replacing the battery is achieved by reducing power consumption by scheduling power, introducing a "sleep" mode and the use of non-volatile functional units.

The operation of the device at an ambient temperature of -45 ^o C to +55 ^o C is achieved by installing the electronic part of the device in a sealed protective box and creating the thermal regime necessary for the operation of the liquid crystal display.

 Industrial applicability.

 The inventive measuring instrument of corrosion parameters has passed the tests, which gave positive results. The device received a certificate of conformity.

 The corrosion parameter meter is designed to work with any two-electrode sensors, as well as sensors with flush disk electrodes. In this case, there is no rigid reference to the length of the probe cable (sensor) and its parameters.

 Basic technical data of the device.

1. The measurement range of Rmp - resistance of the interelectrode gap of the probe is from 0.5 to 9 • 10 ⁴ Ohms.

 2. The limit of the permissible value of the relative error of 5%.

3. The measurement range of I _cor - corrosion current is from 0.02 μA to 500 mA.

4. The measuring range of V _COR - corrosion rate is from 0.001 to 100 mm / year.

 5. The capacity of the memory module is at least 32,000 data packets.

The device provides 100 hours of continuous operation in laboratory conditions or 1.5 weeks of battery life in real conditions at T _ISM = 6 hours and T _cm <15 s.

Claims (5)

1. A corrosion parameter meter, comprising a sensor-converter of informative quantities into electrical signals, a non-volatile memory module and a power source located in the housing, an electrical connector, a temperature sensor, a signal preprocessing unit, the output of which is connected to the input of a multi-channel analog-to-digital converter (MACP) ), including a multiplexer and an ADC, as well as a microprocessor, including a controller, random access memory and a real-time timer, distinguishing the fact that a second electrical connector, a power controller, a keyboard, a liquid crystal display, a real-time clock and a heating element are inserted into the housing, the microprocessor is connected by corresponding one-way connections to the signal preprocessing unit, the liquid crystal display, and the corresponding two-way connections - with a MASP, keyboard, real-time clock, temperature sensor, power controller and the first electrical connector, which they are connected with the information outputs in parallel with the digital outputs of the MACP, the second electrical connector is connected by two-way connections to the signal preprocessing unit, the power controller with its three control outputs is respectively connected to the first electrical connector, the heating element and the signal preprocessing unit together with a liquid crystal display, the power supply is connected to corresponding power inputs of the temperature sensor, real-time clock, MACP, microprocess a quarrel, as well as a power controller, a non-volatile memory module connected by two-way connections to the first electrical connector, and the housing with the functional blocks and elements placed in it are placed in a sealed protective box equipped with a third electrical connector, the inputs connected through the cable to the sensor-sensor of informative values in electrical signals, and outputs through a cable inside the box with a second electrical connector. 2. The corrosion parameter meter according to claim 1, characterized in that the primary converter of informative values into electrical signals is made in the form of a probe comprising two sensor electrodes connected to a cable. 3. The corrosion parameter meter according to claim 1, characterized in that the housing contains two electrical connectors mounted on its end side, and a front panel on which the keyboard field and the LCD panel are located, while the temperature sensor and the heating element are located near the display and have a thermal connection with it. 4. The corrosion parameter meter according to claim 1, characterized in that the sealed protective box is made of high-strength material, such as polystyrene, and consists of a cover and a base with an electrical connector on its end side connected to a cable providing connection to a second electrical connector case, and has a filler from a material with low thermal conductivity, such as polystyrene, thermon or isolon, while the cable is located between the base and the filler, and the box is equipped with brackets for installation in a suspended state. 5. The corrosion parameter meter according to claim 1, characterized in that the non-volatile memory module is removable, with the ability to connect to the first electrical connector from the outside of the housing.

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