Intelligent sensing system for flotation liquid level measurement

Abstract

The invention discloses an intelligent sensing system for flotation liquid level measurement. The intelligent sensing system comprises a sensing unit, an alternating current excitation unit, a signal acquisition unit, a data processing unit (also called as a system control and data processing unit) and an upper computer unit of a PC (Personal Computer) end, the sensing unit is arranged in the flotation tank and is connected with the alternating current excitation unit and the signal acquisition unit through wires; the alternating current excitation unit and the signal acquisition unit are connected with the data processing unit; the data processing unit is connected with the PC end upper computer; the whole sensing unit is in a rod shape, the sensing unit adopts an annular electrode array composed of a plurality of annular electrodes which are arranged at equal intervals in the axial direction, and an isolating ring is arranged between every two adjacent annular electrodes. The intelligent sensing system for measuring the flotation liquid level is easy to implement, and accurate measurement of the flotation liquid level height can be achieved.

Description

Technical Field

[0001] The invention relates to an intelligent sensing system for flotation liquid level measurement. Background Art

[0002] Flotation is the abbreviation of flotation beneficiation, which is one of the important industrial methods for selecting non-ferrous metals. Since the late 19th century, the froth flotation beneficiation production process has developed rapidly in the beneficiation industry and has gradually become one of the most important beneficiation methods in the world. The flotation machine has the characteristics of simple structure, energy saving and high efficiency, and excellent separation performance for fine and difficult-to-select ores. With the increasing scarcity of mineral resources and the increasingly serious global energy crisis, the flotation machine is widely used in the beneficiation industry. The working principle of the flotation machine is as follows: the slurry is added from the top of the flotation machine after being distributed by the feeder, and the air source generated by the air compressor is injected from the bottom of the flotation machine. In the machine body, the rising bubbles collide with the descending ore particles in the countercurrent, and the useful minerals are scraped out with the bubbles, forming a foam layer above the liquid surface. Under the action of various chemical agents, the desired concentrate is finally formed, and then overflows out of the slot as a concentrate product, while other components sink to the bottom and are discharged from the flotation machine in the form of tailings. The entire flotation process involves changes in solid, liquid and gas phases. During the production process, ensuring that the slurry level in the flotation machine is highly stable and controllable can not only ensure long-term effective operation and reduce costs, but also help improve flotation indicators such as mineral utilization and concentrate grade. The development of flotation equipment in my country started late. Since the 1960s, some mines have begun to introduce flotation equipment and gradually realized the localization of flotation machines. As more and more large-scale flotation machines are developed and put into use, manual control can no longer meet the needs of industrial production. Research on liquid level detection and control of large-scale flotation equipment in my country is becoming more and more important.

[0003] Existing foam layer thickness detection methods include float detection method, pressure detection method, capacitance detection method, visual image detection method, etc. However, due to the difficulties in cleaning, large steady-state errors, complex processes, and time-consuming nature of these methods, the accuracy and reliability of existing foam layer thickness detection are relatively low.

[0004] As for the froth layer thickness detection control circuit in the flotation process, some larger flotation machines have been promoted and used abroad and are equipped with corresponding automatic control systems. However, there is still a lack of long-term and reliable use examples in the automatic control of slurry flotation in China, and there are no standardized products suitable for slurry froth thickness measurement and automatic control. The flotation machines used in flotation in many mines lack automatic control systems and still generally use inefficient manual control. This method has the problems of high labor intensity and low flotation efficiency.

[0005] Therefore, it is necessary to design an intelligent sensing system for flotation level measurement (i.e., foam thickness measurement). Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an intelligent sensing system for flotation liquid level measurement, which can realize rapid measurement and is easy to implement.

[0007] The technical solution of the invention is as follows:

[0008] An intelligent sensing system for flotation level measurement, comprising a sensing unit, an AC excitation unit, a signal acquisition unit, a data processing unit (also called a system control and data processing unit), and a host computer unit on a PC side;

[0009] The sensor unit is arranged in the flotation tank and connected to the AC excitation unit and the signal acquisition unit through a wire;

[0010] The AC excitation unit, the signal acquisition unit and the data processing unit are connected;

[0011] The data processing unit is connected to the PC host computer;

[0012] The sensing unit is rod-shaped or tubular as a whole. The sensing unit adopts an annular electrode array composed of a plurality of annular electrodes arranged equidistantly along the axial direction, and an isolation ring is arranged between adjacent annular electrodes.

[0013] The middle of the sensing unit is filled with epoxy resin for sealing and insulation.

[0014] The thickness of the annular electrode is 10 mm and the outer diameter is 60 mm, and the thickness and outer diameter of the isolation ring are both 60 mm. A reinforcing tube is provided inside the sensing unit.

[0015] The AC excitation unit includes a digital isolation circuit, a signal generator circuit, a filter circuit, a voltage-controlled current source circuit, and an analog multi-way switch circuit connected in sequence; the signal generator circuit generates a voltage signal with adjustable frequency and amplitude, and after filtering out high-frequency clutter signals through the filter circuit, it is converted into a current signal through the voltage-controlled current source circuit. The voltage signal has an amplitude of 0-5V, a frequency of 0-10kHz, and a current signal amplitude of 0-20mA.

[0016] 6. The intelligent sensing system for flotation level measurement according to claim 1 is characterized in that the signal acquisition unit comprises a digital isolation circuit, an A / D converter, a filter circuit, a differential amplifier, and a sampling circuit connected in sequence. The slurry voltage of different annular electrodes is collected by the sampling circuit, and the voltage signal is amplified and filtered by the differential amplifier and the filter circuit, and then converted into a digital signal by the A / D converter and transmitted to the data processing unit after isolation. The filter circuit adopts a Butterworth low-pass filter to filter out high-frequency clutter signals and ensure that the frequency response curve in the passband is as flat as possible.

[0017] In the AC excitation unit, two multiplexing chips are used for gating control; the two multiplexing chips are a first multiplexing chip and a second multiplexing chip;

[0018] The sensing unit comprises n uniformly arranged electrodes arranged in the object to be measured; the electrodes are ring electrodes;

[0019] The voltage-controlled current source circuit includes a first excitation current output module and a second excitation current output module;

[0020] The first excitation current output module is connected to the input terminal D of the first multiplexing chip, and the n output terminals S1-Sn of the first multiplexing chip are respectively connected to n electrodes; the control terminals A0-Ai of the first multiplexing chip are respectively connected to the i+1 IO ports of the controller in the control system; the relationship between i and n is: 2^i≤n≤2^

[0021] (i+1);

[0022] The second excitation current output module is connected to the input terminal D of the second multiplexing chip, and the n output terminals S1-Sn of the second multiplexing chip are respectively connected to n electrodes; the control terminals A0-Ai of the second multiplexing chip are respectively connected to the i+1 IO ports of the controller in the control system; the relationship between i and n is: 2^i≤n≤

[0023] 2^(i+1);

[0024] The controller controls the kth electrode to be connected to the first excitation current through the control terminal A0-Ai, and controls the k+1th electrode to be connected to the second excitation current, and obtains the current conductivity data from the kth electrode or the k+1th electrode; k takes values ​​from 1 to n-1 in sequence; and finally obtains n-1 groups of conductivity data.

[0025] n is 12 or 16, and i is 3.

[0026] The electrode is an electrode type conductivity sensor, including: a cylindrical substrate, multiple metal electrode rings and multiple isolation rings; the multiple isolation rings are mounted on the cylindrical substrate and are coaxial with the cylindrical substrate; the multiple metal electrode rings are embedded in the gaps of the isolation rings and are coaxial with the cylindrical substrate; each metal electrode ring has a lead wire.

[0027] The excitation voltage signal has an amplitude of 0-5V, a frequency of 0-10kHz, and a current signal amplitude of 0-20mA. Beneficial effects:

[0028] The intelligent sensing system for flotation level measurement of the present invention comprises a sensing electrode unit, an AC excitation unit, a signal acquisition unit, a system control and data processing unit and a PC-end host computer; the sensing electrode unit is arranged in a pulp flotation tank and is connected to the AC excitation unit and the signal acquisition unit through a wire; the AC excitation unit and the signal acquisition unit are connected to the system control and data processing unit, and the system control and data processing unit is connected to the PC-end host computer. The electrical impedance parameters of the pulp in the flotation tank are collected by the sensing electrode, and the data are transmitted to the system control and data processing unit through the signal acquisition unit. The system control and data processing unit converts the electrical impedance into liquid level height and foam layer thickness, and then transmits it to the PC-end host computer; the PC-end host computer performs real-time display of the liquid level height and storage of historical data, thereby realizing accurate measurement of the flotation liquid level height. The present invention measures the conductivity (or resistivity) distribution inside the slurry by using a multi-channel selective electrode array; the method has a simple structure, is easy to implement, has high measurement accuracy, and has a fast calculation speed. The detection method is convenient for fast real-time detection and processing of signals and implementation of embedded systems, and can continuously and long-term detect the measured signal. The method can realize fast real-time detection and calculation of conductivity parameters, and provide a scientific basis for studying the thickness of slurry flotation foam, liquid level, and ore dressing accuracy.

[0029] The conductivity detection method adopted by the present invention is to use the conductive properties of the slurry to determine the interface between the slurry and the foam, and to calculate the thickness of the foam layer during flotation. He Shengchun et al. proposed a conductivity probe structure in which multiple electrode spirals are evenly arranged and four common electrodes form a measurement loop, which realizes the conductivity measurement of different positions in the flotation machine, but does not define the slurry layer and the foam layer. The present invention uses a single probe annular electrode for measurement, which has a simple structure and improves efficiency. The annular electrode can adapt to slurry and corrosive substances, thereby avoiding errors caused by solid sedimentation on the electrode surface, and can define the slurry layer and the foam layer according to the measurement curve, effectively solving the problems of adapting to slurry corrosion and low accuracy in the flotation foam layer thickness measurement process (the foam layer thickness is further calculated by conductivity or resistivity (obtained through data analysis, not within the scope of the present invention, and is an existing mature technology, because the conductivity of the foam layer and the liquid layer is completely different). BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of a multi-channel selection module according to an embodiment of the present invention.

[0031] Figure 2 It is a schematic front view of the sensor detection device.

[0032] Figure 3 It is a longitudinal (along the electrode axis) cross-sectional view of the sensor detection device.

[0033] Figure 4 It is a display of the test data (curve) of a small flotation machine.

[0034] Figure 5 It is the overall system principle block diagram of the present invention;

[0035] Figure 6 It is a schematic diagram of a three-dimensional view of the needle-shaped sensor in the present invention.

[0036] Description of labels:

[0037] In the figure: 1-1-control system, 1-2-multiplexing switch chip, 1-3-detection module, 2-1-conducting wire, 2-2-annular metal ring electrode monomer, 2-3-isolation ring, 2-4-process hole, 2-5-isolation ring cover, 2-6-isolation ring bottom, 2-7-flotation tank, 2-8-fixed bracket, 3-1-reinforcement tube. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0039] Example 1: Figure 1-3 ,like Figure 1 As shown, it is a schematic diagram of a multi-channel selection module of an embodiment of the present invention. There are two multiplex switch chips 1-2, and the control system 1-1 is respectively connected to the input terminal D, address terminals A0, A1, A2, and A3 of the corresponding chip. The 12 single channels of each chip are respectively connected to the annular array electrodes 2-3 in the detection module 1-3 in sequence.

[0040] Among them, the annular array electrode 2-3 in the detection module 1-3 is divided into odd-numbered annular metal ring electrode monomers and even-numbered annular metal ring electrode monomers, and the multiplex switch chip 1-2 realizes the conversion of the measuring electrode pair by changing the address bit. The specific implementation example is as follows: Assume that the multi-channel detection device for slurry level starts detection in the first detection cycle, the 12 single-channel outputs of the multiplex switch chip a are connected to the odd-numbered electrodes, and the 12 single-channel outputs of the multiplex switch chip b are connected to the even-numbered electrodes. When the first detection cycle arrives, the control system controls the two multiplex switch chips to simultaneously select electrode 1 and electrode 2 , at this time, electrode 1 and electrode 2 constitute a liquid level detection electrode pair; when the second detection cycle arrives, the control system inputs the address bit of the multiplexing switch chip a plus one, while the address bit input to the multiplexing switch chip b remains unchanged, so that electrode 2 and electrode 3 are selected and constitute a liquid level detection electrode pair; when the third detection cycle arrives, the control system inputs the address bit of the multiplexing switch chip b plus one, while the address bit input to the multiplexing switch chip a remains unchanged, thereby selecting the next pair of electrodes, and so on, until the last electrode is selected, and a measurement cycle ends. The scanning frequency in the embodiment of the present invention is 400ms

[0041] like Figure 2 , which is a schematic front view of the sensor detection device, Figure 3 It is a schematic cross-sectional view of a sensor detection device, wherein the detection module is an electrode-type conductivity sensor, comprising a wire 2-1 with an outer skin, an annular metal ring electrode monomer (also called a metal electrode ring body) 2-2, an isolation ring (also called an isolation ring body) 2-3, a process hole 2-4, an isolation ring cover 2-5, an isolation ring bottom 2-6, and a reinforcing tube 3-1; the isolation ring cover, the annular metal ring electrode monomer, the isolation ring, the process hole, and the isolation ring bottom are sequentially connected; the annular metal ring electrode monomer and the isolation ring are equidistantly and staggeredly inlaid in the sensor probe; the detection module is located in a liquid pool 2-7 composed of multiphase flows of different conductivities to realize conductivity detection, and the detection sensor is fixed by a fixed bracket 2-8;

[0042] The overall length of the probe electrode in this embodiment is set to 1200mm, with connecting screws, a reinforcing tube 3-1 inserted inside, the wire 2-1 passes through the reinforcing tube, and is connected to the bottom of the isolation ring by threads and connected to the connecting seat by pins. The reinforcing tube is insulated and isolated by epoxy resin glue filled through process holes, and the process holes on the outside of the parts are sealed with epoxy resin glue, and the surface is smooth, neat and not deformed.

[0043] The isolation ring cover 2-5 and the isolation ring bottom 2-6 are respectively located at the top and bottom of the sensor probe, and are made of POM plastic, black in color, with a smooth surface without burrs, an inner diameter of 50mm, an outer diameter of 60mm, and a ring height of 27mm.

[0044] The annular metal ring electrode monomers 2-2 and the isolation rings 2-3 are staggered and equidistantly inlaid on the surface of the sensor probe, wherein the number of the annular metal ring electrode monomers is 24, the material is stainless steel, the surface is smooth and burr-free, the inner diameter of the ring is 50mm, the outer diameter of the ring is 60mm, the height of the ring is 10mm, and each ring electrode has a wire for signal transmission; the number of the isolation rings is 23, the material is POM plastic, the color is black, the surface is smooth and burr-free, the inner diameter of the ring is 50mm, the outer diameter of the ring is 60mm, and the height of the ring is 43mm, and the isolation ring is connected to the upper and lower annular metal ring electrode monomers; the metal ring electrodes are grouped in pairs to form a liquid level detection electrode pair, and the control system controls the multi-channel selection module to realize the detection switching of each pair of electrodes.

[0045] The process holes 2-4 are located in the center of the 23 isolation rings, isolation cup covers and isolation cup bottoms, and are process holes generated during the processing of the probe electrodes, and epoxy resin is injected through the process holes.

[0046] The number of wires 2-1 is 24, and the wire diameter is 0.5mm 2, the outer diameter is not more than 1mm, and the whole product wire is led out through the aviation plug; the detection module is located in the flotation cell 2-7 composed of fluids with different electrical conductivities to realize detection. The flotation cell contains the pulp layer and the foam layer of the mining and metallurgical flotation process. Due to the action of reagents and mechanical stirring, the foam layer is located at the upper part of the flotation cell and the pulp layer is located at the lower part of the flotation layer. The probe electrode must pass through the foam layer and be placed in the pulp layer.

[0047] The sensor detection device is an electrode-type conductivity sensor, which has n annular electrodes. Under the control of the multi-channel selection module, an excitation current in the range of 0.1mA-20mA is applied to the flotation cell and the measured voltage values ​​of (n-1) groups of fluids with different conductivity are obtained. According to Ohm's law and the inverse relationship between conductivity and resistivity, the relationship between the conductivity σ of the object being measured and the excitation current I, the measurement voltage U, the length l of the conductor being measured, and the cross-sectional area A of the conductor being measured is:

[0048]

[0049] like Figure 4 As shown in the figure, it is the test data of a small flotation machine. The horizontal axis is the 23-channel electrode pair, and the vertical axis is the measured voltage value. From the measured voltage curve, the measured voltage value of the AB segment, i.e. the 1st to 4th electrode group, is small and stable, which is the pulp layer. This is because the pulp contains some target minerals. Under the influence of excitation, it has stronger conductivity and has little effect on the stability of the conductivity of the part in contact with the pulp near the sensor unit. The measured voltage value of the CD segment, i.e. the 12th to 23rd electrode group, is large and stable, which is the air layer. This is because the electrode is almost open in the air layer. Due to the hardware characteristics, the measured voltage value is close to 4.038v. The conductivity between the foam layers changes significantly, which is shown in the measured voltage value of the BC segment, i.e. the 4th to 12th electrode group. As the bubbles in the foam layer gradually increase as they float up, the obstruction to the current increases, reducing the conductivity of the foam layer. The thicker the foam layer, the slower the change trend. Point B is the interface between the slurry layer and the foam layer, and point C is the interface between the foam layer and the air layer. Based on the above analysis, the measurement voltage result curve of the present invention can simply and intuitively define the slurry layer and the foam layer, thereby determining the position of the interface (interface) and thus determining the thickness of the foam layer; the scanning frequency is 400ms per cycle, realizing a highly efficient, accurate, simple and intuitive multi-channel selective electrode array conductivity measurement device and method, on this basis, the thickness of the foam layer can be further calculated or determined.

[0050] like Figure 5 As shown, an intelligent sensing system for flotation liquid level measurement includes a sensing electrode unit, an AC excitation unit, a signal acquisition unit, a data processing unit and a host computer;

[0051] The sensing electrode unit is arranged in the flotation tank and connected to the AC excitation unit and the signal acquisition unit through a wire;

[0052] The AC excitation unit, the signal acquisition unit and the data processing unit are connected;

[0053] The data processing unit is connected to the PC host computer.

[0054] like Figure 6 As shown, the sensing electrode unit is a ring electrode array, which uses multiple ring electrodes with a height of 10 mm and an outer diameter of 60 mm, which are arranged equidistantly along the axial direction, with an isolation ring with an outer diameter of 60 mm nested in the middle, and epoxy resin is poured inside for sealing and insulation. The ring electrode and the isolation ring are nested in a stainless steel connecting seat and connected to the stainless steel extension rod through the connecting seat.

[0055] The annular electrode is made of stainless steel 316;

[0056] The isolation ring is made of polytetrafluoroethylene;

[0057] In order to ensure the overall structural strength, a reinforcement tube is added inside the sensor unit ring to improve and meet the strength requirements of the rod body.

[0058] Epoxy resin glue is poured into the electrode ring to ensure the overall sealing of the electrode ring assembly.

[0059] When the sensor is working, the electrode is placed in the ore pulp as a whole, the AC excitation unit applies AC current to adjacent annular electrodes in turn, and the ore pulp impedance is collected through the signal acquisition unit.

[0060] The AC excitation unit includes a digital isolation circuit, a signal generator circuit, a filter circuit, a voltage-controlled current source circuit, and an analog multi-way switch circuit.

[0061] Among them, a voltage signal with adjustable frequency and amplitude is generated by a signal generator circuit. After the high-frequency clutter signal is filtered out by a filter circuit, it is converted into a current signal by a voltage-controlled current source circuit and applied to different annular electrodes through an analog multi-way switch. The slurry is in direct contact with the annular electrode and will generate a voltage value after being excited by the current. The impedance value can be calculated based on this voltage value.

[0062] The signal acquisition unit includes a digital isolation circuit, an A / D converter, a filter circuit, a differential amplifier, and a sampling circuit.

[0063] Among them, the slurry voltage of different annular electrodes is collected through the sampling circuit, the voltage signal is amplified and filtered through the differential amplifier and filter circuit, and then converted into a digital signal through the A / D converter and transmitted to the system control and data processing unit.

[0064] The system control and data processing unit is a high-performance MCU, which is responsible for controlling the AC excitation unit and the signal acquisition unit, and digitally demodulating and converting the obtained data. Finally, the liquid level and the thickness of the foam layer are obtained, the foam layer is imaged, and it communicates with the host computer.

[0065] The whole lower computer program adopts the lightweight FreeRTOS real-time operating system, and creates four subtasks: communication mode initialization, excitation source frequency and amplitude initialization, sampling channel initialization, and AD sampling and data processing initialization. After the FreeRTOS task scheduling is turned on, the whole lower computer program starts to run, detects the subtask change state, and modifies the corresponding subtask when the received control instruction changes, otherwise the default setting is used. After the setting is completed, the AD sampling part collects data from 24 channels. The collection method is to collect the voltage data between two adjacent electrodes in sequence. 24 electrode channels can obtain 23 sets of voltage data. The channel switching method is controlled by the channel control part program (the default is to collect adjacent channels in sequence, and other collection methods can be set to adapt to different algorithms). The collected channel data is first pre-processed in the lower computer. 250 data points are collected between every two adjacent channels to form a group, and the middle 100 data (4 periodic waveforms) are taken to avoid interference at both ends caused by waveform establishment time and channel switching. Then, the processed data is subjected to FFT transformation to obtain the frequency and amplitude characteristics of the measurement signal. The obtained amplitude-frequency characteristics are used to calculate the liquid level and the thickness of the foam layer. The measured data and the calculated results are transmitted to the host computer through communication for storage and display. The default communication method is LAN port UDP communication. Different subtasks can be called by sending selection information to the slave computer or changing the "communication selection" hardware IO port status (used to select the communication method), thereby selecting different communication methods: DMA+RS232 serial communication, USB communication, TCP communication, etc. The frequency and amplitude changes of the excitation source of the test system and the channel switching method can be modified by the host computer, so as to achieve the purpose of multi-frequency, adjustable amplitude and diverse excitation methods.

[0066] The host computer software is a software written by QT software and can run on different platforms. The main functions of the host computer in the present invention are to complete communication with the slave computer, display data in real time, provide users with an interactive interface for modifying the parameters of the slave computer, and store data.

[0067] When the host computer starts running, it will complete the initialization of controls such as the waveform and timer, and wait for the confirmation communication button to be clicked before continuing to run. After the host computer detects that the confirmation communication button is pressed, it sets the configured serial port parameters and calls the function to open the serial port. After successful communication with the lower computer, the host computer software starts the waveform refresh timer and keeps running the data acquisition subroutine, data storage subroutine, and data display subroutine until the host computer software stops running.

[0068] The host computer software is a software written by QT software and can run on different platforms. The main functions of the host computer in the present invention are to complete communication with the slave computer, display data in real time, provide users with an interactive interface for modifying the parameters of the slave computer, and store data.

Claims

1. An intelligent sensing system for flotation level measurement, characterized in that: It includes a sensor unit, an AC excitation unit, a signal acquisition unit, a data processing unit (also called a system control and data processing unit), and a host computer unit on the PC side; The sensor unit is arranged in the flotation tank and connected to the AC excitation unit and the signal acquisition unit through a wire; The AC excitation unit, the signal acquisition unit and the data processing unit are connected; The data processing unit is connected to the PC host computer; The sensing unit is rod-shaped or tubular as a whole. The sensing unit adopts an annular electrode array composed of a plurality of annular electrodes arranged equidistantly along the axial direction, and an isolation ring is arranged between adjacent annular electrodes.

2. The intelligent sensing system for flotation level measurement according to claim 1 is characterized in that: The middle of the sensing unit is filled with epoxy resin for sealing and insulation.

3. The intelligent sensing system for flotation level measurement according to claim 1 is characterized in that: The thickness of the annular electrode is 10 mm and the outer diameter is 60 mm, and the thickness and outer diameter of the isolation ring are both 60 mm.

4. The intelligent sensing system for flotation level measurement according to claim 1 is characterized in that: A reinforcement tube is provided inside the sensor unit.

5. The intelligent sensing system for flotation level measurement according to claim 1 is characterized in that: The AC excitation unit includes a digital isolation circuit, a signal generator circuit, a filter circuit, a voltage-controlled current source circuit, and an analog multi-way switch circuit which are connected in sequence; a voltage signal with adjustable frequency and amplitude is generated by the signal generator circuit, and after the high-frequency clutter signal is filtered out by the filter circuit, it is converted into a current signal by the voltage-controlled current source circuit.

6. The intelligent sensing system for flotation level measurement according to claim 1 is characterized in that: The signal acquisition unit includes a digital isolation circuit, an A / D converter, a filter circuit, a differential amplifier, and a sampling circuit connected in sequence. The slurry voltage of different annular electrodes is collected through the sampling circuit, and the voltage signal is amplified and filtered through the differential amplifier and the filter circuit, and then converted into a digital signal through the A / D converter and transmitted to the data processing unit after isolation.

7. The intelligent sensing system for flotation level measurement according to claim 5, characterized in that: In the AC excitation unit, two multiplexing chips are used for gating control; the two multiplexing chips are a first multiplexing chip and a second multiplexing chip; The sensing unit comprises n uniformly arranged electrodes arranged in the object to be measured; the electrodes are ring electrodes; The voltage-controlled current source circuit includes a first excitation current output module and a second excitation current output module; The first excitation current output module is connected to the input terminal D of the first multiplexing chip, and the n output terminals S1-Sn of the first multiplexing chip are respectively connected to n electrodes; the control terminals A0-Ai of the first multiplexing chip are respectively connected to i+1 IO ports of the controller in the control system; the relationship between i and n is: 2^i≤n≤2^(i+1); The second excitation current output module is connected to the input terminal D of the second multiplexing chip, and the n output terminals S1-Sn of the second multiplexing chip are respectively connected to n electrodes; the control terminals A0-Ai of the second multiplexing chip are respectively connected to i+1 IO ports of the controller in the control system; the relationship between i and n is: 2^i≤n≤2^(i+1); The controller controls the kth electrode to be connected to the first excitation current through the control terminal A0-Ai, and controls the k+1th electrode to be connected to the second excitation current, and obtains the current conductivity data from the kth electrode or the k+1th electrode; k takes values ​​from 1 to n-1 in sequence; and finally obtains n-1 groups of conductivity data.

8. The intelligent sensing system for flotation level measurement according to claim 7 is characterized in that: n is 12 or 16, and i is 3.

Images