WO2019080292A1 - Microwave solid flowmeter detection system and device - Google Patents

Abstract

A microwave solid flowmeter detection system, comprising a Doppler echo collection module, a sensing plate, a conversion plate and an upper computer, wherein the sensing plate includes an A/D analog-to-digital conversion module, a filter downsampling module and an FPGA signal processing system; and the conversion plate is used for converting a digital signal into a current signal so as to output a current acting as a signal source of the display device. The detection system is used to process signals of a microwave solid flowmeter, and the functions of each module are completely designed. The signals are subjected to smoothing and constant false alarm processing multiple times by means of an FPGA, thereby overcoming the disadvantages of a traditional flowmeter and realizing accurate measurement and monitoring of flow information. The system is highly sensitive, has a strong anti-interference ability and is easy to control.

Description

Microwave solid flowmeter detection system and device Technical field

The invention belongs to the technical field of solid flow meters, and particularly relates to a microwave solid flow detection system and device, which can be used for mobile solids monitoring in many industries such as metallurgy, environmental protection, pulp and paper, ore, nuclear power, and chemical industry.

Background technique

Online accurate measurement of flow rate has always been a difficult point in the development of flowmeters, and one of the difficulties in industrial measurement parameters. Traditional flowmeter detection methods have problems such as demanding inspection scenarios, high manufacturing costs, and difficult to evaluate real-time measurement accuracy. With the development of the economy and the improvement of the industrial level, the dosing and dosing of materials such as solids, granules and powders has become the key to industrial process control. In recent years, with the rapid development of microprocessors, the online measurement technology of smart meters has emerged as the times require. The online flow test method is a trend in the field of modern fluid measurement.

The microwave solid flow meter uses a 24 GHz high frequency microwave to generate a measurement field through the coupling of the electromagnetic field between the sensor and the pipe. As the detected medium passes from the microwave detection field, the sensor transmits low power microwaves and receives the energy reflected back by the object. The received microwave reflection frequency and the transmission frequency produce a frequency difference, thereby generating a low frequency AC voltage at the output, that is, the number and flow rate of the moving medium detected by the microwave sensor. The microwave energy of the measurement field is reflected back by the solid particles and received by the receiver. According to the Doppler principle, only the flowing particles of the microwave solid flow meter can be measured, and the flow rate (mass) can be calculated in combination with the number and state of the recorded particles. The microwave solid flow meter receiving data processor is adjusted by the Doppler effect. The speed of material transfer speed only changes the speed of the signal received by the probe, media visualization, and process automation.

In the prior art, CN205785360U discloses a solid flow meter comprising a base (1), a motor (2), a solar cell (3), a rotating blade (4), a feed port (5), a rotating shaft (6), and charging. Port (7), controller (8), display (9), button (10), discharge port (11), pressure sensor (12), metering chamber (13), outside a casing (14), the base (1) is provided with a motor (2), a solar battery (3) and a controller (8), and a display screen and a button (10) are arranged on the controller (8). The rotating shaft (6) is connected to the rotating blade (4), and the feeding port (5) is arranged at the upper end of the flow meter, and the discharging port (11) is arranged at the lower end, and the two pressure sensors (12) are oppositely arranged to form the discharging port. (11) The metering chamber (13) is connected to the outer casing (14). It has a complicated structure and poor online maneuverability.

CN105865546A is designed to solve the problem of pressure and dust leakage caused by the rupture of the ceramic tube of the existing solid flowmeter. The solid flowmeter installation structure is a metal casing provided on the conveying pipe and an electrical box connected with the metal casing, and the metal casing is inside. A solid flow meter is arranged, a ceramic tube of the solid flow meter forms a seal with the metal casing, a measuring electrode of the solid flow meter is connected with a circuit board in the electrical box, and a sealing spacer is arranged between the solid flow meter and the electrical box, and the measurement is performed. The electrode is connected to the circuit board via a sealing spacer, and the sealing spacer is used to isolate the solid flow meter from the electrical box. However, it does not solve the problem of online real-time monitoring and regulation.

Therefore, the existing flowmeter has the defects of low on-line measurement data, lag of signal feedback, low computational efficiency, and strict requirements for on-line monitoring conditions, especially the detection of high-speed solid fluids. When the flow rate is greater than a certain flow rate, the operation efficiency is low, and the signal is delayed. Can not truly reflect the change in solid flow rate.

Summary of the invention

The object of the invention is to overcome the defects of inaccurate detection, low sensitivity, poor real-time performance and poor operability of the solid flow meter, and to provide a microwave solid flowmeter detection system and device, which realizes flow information by setting FPGA and phase-locked loop. Accurate measurement, monitoring, high sensitivity, strong anti-interference ability, easy to control, real-time monitoring of solid transport.

According to an aspect of the present invention, a microwave solid flowmeter detection system is provided, including a Doppler echo acquisition module, a sensor board, a conversion board, and a host computer, wherein the sensor board includes an A/D analog-to-digital conversion module. The filter downsampling module and the FPGA signal processing system; the conversion board is used for converting the digital signal into a current signal and performing current output as a signal source of the display device. The FPGA signal The system is used for time domain and frequency domain signal conversion, speed smoothing, constant false alarm processing, and flow value statistics. The I and Q analog signals containing Doppler information collected by the high-precision chip are converted into digital signals, which are used as signal sources of the FPGA digital signal processing system.

Preferably, the Doppler echo acquisition module is a radio frequency transceiver integrated structure for transmitting and receiving signals, specifically adopting a transceiver integrated chip for transmitting and receiving signals; and a phase locked loop inside the voltage control chip Generate a stable carrier signal, transmit it through the waveguide, and then receive the echo signal containing the carrier and Doppler frequency. After orthogonal processing by the LNA and the mixer, the carrier signal is filtered out to generate only Doppler. The I and Q quadrature signals of the information are used for subsequent processing.

Preferably, the Doppler echo acquisition module comprises a crystal oscillator, a phase locked loop, a CPLD, a transceiver integrated chip, and a microwave probe. The phase-locked loop circuit is used, and the transmission power and frequency of the microwave head can be changed by software without being affected by temperature.

Preferably, the system includes an anti-aliasing filter for filtering and downsampling.

Preferably, the upper computer controls the working mechanism of the conversion board and the sensing board by communicating with the conversion board and the sensing board.

Preferably, the host computer is configured to send instructions and parameters to the FPGA to control its working mechanism while receiving data for display.

According to another aspect of the present invention, a microwave solid flowmeter detecting device includes a sensor body, an electrical box, and a host computer, wherein the electrical box includes a conversion board, the sensor body is connected to the probe, and the flow meter probe is fixed to the solid to be tested. On the wall of the flow line, the angle between the probe and the solid flow direction is 15°<θ<90° or 90°<θ<165°, and the upper computer is connected to the conversion plate.

Preferably, the probe is at an angle of 30° < ≦ θ ≦ < 60°, further preferably 45° to the solid flow direction. By adjusting the angle between the probe and the solid flow direction, the microwave field is controlled to maximize the effective collection area of the solid fluid and the microwave field, reduce the interference of the echo reflection signal to the phase-locked loop, and improve the Doppler echo. Acquisition accuracy.

Preferably, the multi-probes are arranged in a horizontal ring array, a vertical line array, and a circular vertical array.

Preferably, the multi-probe structure, the probe separately collects Doppler echo signals, does not interfere with each other, each probe corresponds to an independent signal processor, and the processed signals are collected in the same conversion board for digital-to-analog conversion of signals.

Preferably, the FPGA is configured in an active serial mode, a passive serial mode, and a JTAG mode.

Preferably, it also contains a 4-20 mA circuit loop.

Preferably, the sensor body has a columnar structure, and comprises a microwave transmitting device, a microwave receiving device, an A/D analog-to-digital conversion device, a filter downsampling device, an FFT transform and an amplitude spectrum calculating device.

Preferably, the microwave transmitting device is a variable frequency adjustable power microwave transmitting device.

Preferably, the phase inversion chip is included in the microwave emitting device.

Preferably, the microwave transmitting device comprises a waveguide, a frequency sweep signal generator and a point frequency signal generator.

Preferably, the microwave transmitting device and the microwave receiving device are integrated into a radio frequency transceiver integrated structure for transmitting and receiving microwave signals.

Preferably, the FT transform and the amplitude spectrum calculation are implemented by an FPGA digital signal processor, and the microwave signal received by the microwave digital receiving device passes through the digital-to-analog conversion device and enters the FPGA digital signal processor.

According to another aspect of the present invention, a method for solid flow detection is provided, comprising the steps of: collecting a Doppler echo; performing an A/D analog-to-digital conversion on the echo; filtering and downsampling the digital signal; The signal processing system performs fast Fourier FFT calculation, calculates the amplitude spectrum; obtains the solid flow velocity and flow value parameters through the velocity spectrum; calibration processing, calibrates the relationship between the solid flow value and the velocity, and converts the obtained value into corresponding The current signal is output for data display.

Compared with the prior art, the present invention has the following beneficial effects:

The invention adopts a microwave solid flow meter to detect the velocity and flow rate of the fluid. The device and the system comprise an FPGA digital signal processing system, a transceiver integrated Doppler echo acquisition system, a phase locked loop circuit, and a plurality of signals are filtered and smoothed. Processing, accurate measurement and monitoring of flow information, high sensitivity, strong anti-interference ability, easy to control, real-time monitoring of solid transport. Especially for the detection of high-speed solid fluids, when the flow rate is higher than a certain flow rate, the high calculation efficiency can ensure the true reflection of the solid flow rate change. For example, when the flow rate is greater than 1.5t/h, the detection system can reflect the change of the solid flow rate in real time.

The microwave solid flowmeter adopts advanced sensing and microwave technology, and the closed-loop control is carried out online through the control system, which ensures real-time and accurate monitoring of the flow in the feed pipe, optimizes the conveying system and combustion conditions. FPGA is used, and high-speed AD acquisition chip is used at the same time. The signal from the microwave head is collected at high speed, and complex algorithms are used to process the signal. The flow of materials can be measured and stored online, and the transportation rules can be established according to the needs. The phase-locked loop circuit is used to change the transmit power and frequency of the microwave head through software without being affected by temperature. Microwave emission is realized by variable frequency adjustable power microwave transmitting device. Under the changes of material environment, reaction substance polarity, specific gravity, solid flow rate and other parameters, the overshoot phenomenon is overcome, and the microwave transmitting power and frequency are adjusted according to the feedback of the flow rate. To accurately detect real-time traffic of materials. According to the working conditions, the power and frequency are adjusted in real time to achieve the desired control and detection results. The radio frequency transceiver integrated structure is used for transmitting and receiving microwave signals, and has excellent performance, few peripheral components, low power consumption, and easy control and operation. And according to the real-time flow of materials, the amount of additives can be controlled, the quality of the products can be stabilized, and the cost can be reduced. By adjusting the angle between the probe and the solid flow direction, the microwave field is controlled to maximize the effective collection area of the solid fluid and the microwave field, and the accuracy of the Doppler echo acquisition is improved. The on-line measurement is carried out by using a microwave solid flow meter, and the material conveying amount becomes clear and transparent, and the ratio can be adjusted at will, thereby achieving continuous operation of the system.

DRAWINGS

Figure 1 is a schematic diagram of a microwave solid flowmeter detection system

Figure 2 is a schematic diagram of the signal processing system

Figure 3 shows the installation of the probe and flow channel.

4 is an external view of a microwave solid flow meter of a specific embodiment

Detailed ways

The content of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Figure 1 is a schematic diagram of a microwave solid flow meter detection system.

The invention relates to a microwave solid flowmeter detecting system, which comprises a Doppler echo acquisition module, a sensing plate, a conversion board and a host computer, wherein the sensing board comprises an A/D analog-to-digital conversion module, a filter downsampling module, The FFT transform and the amplitude spectrum calculation module are used for converting a digital signal into a current signal and performing current output as a signal source of the display device. The schematic diagram of the system is shown in Figure 1. It includes microwave head, A/D analog-to-digital conversion, filter downsampling, fast Fourier FFT calculation, amplitude spectrum calculation, flow, velocity, concentration and other parameters calculation.

Example 1

A microwave solid flowmeter detection system comprises three independent Doppler echo acquisition modules, a sensing plate, a conversion board and a host computer, and the sensing board comprises an A/D analog-to-digital conversion module, a filter downsampling module, and three FPGA signal processing system, RS485 communication module.

The FPGA signal processing system is used for time domain and frequency domain signal conversion, speed smoothing processing, constant false alarm processing, and flow value statistics. The I and Q analog signals containing Doppler information collected by the high-precision chip are converted into digital signals, which are used as signal sources of the FPGA digital signal processing system. The conversion board is used to convert a digital signal into a current signal for current output as a signal source for the display device. The three FPGA signal processing modules are connected to the conversion board through the RS485 bus, and the logic operation module supplies the operation result to the conversion module for digital-to-analog conversion, and the conversion module is connected with the control module to enter the parameter display. On The bit machine is used to send instructions and parameters to the FPGA to control its working mechanism, while receiving data for display. Filtering and downsampling are performed using an anti-aliasing filter.

The Doppler echo acquisition module is an integrated structure for RF transceiver, used for signal transmission and reception, and specifically uses transceiver integrated chip for signal transmission and reception; including crystal oscillator, phase-locked loop, CPLD, transceiver integration Chip, microwave probe. The phase-locked loop circuit is used, and the transmission power and frequency of the microwave head can be changed by software without being affected by temperature. The phase-locked loop inside the voltage control chip generates a stable carrier signal, which is transmitted through the waveguide, and then receives the echo signal containing the carrier and the Doppler frequency, and after orthogonal processing by the LNA and the mixer, the carrier is filtered out. The signal produces an I, Q quadrature signal containing only Doppler information for subsequent processing.

Example 2

A microwave solid flowmeter detecting device comprises: a sensor body, an electrical box, and a host computer, wherein the electrical box contains a conversion board, and the sensor body is connected with three probes, arranged by a horizontal ring array, and the flowmeter probe is fixed. The wall of the solid flow pipe is measured and installed obliquely. The angle between the probe and the solid flow direction is 45°. By adjusting the angle between the probe and the solid flow direction, the microwave field is controlled to maximize the effective collection area of the solid fluid and the microwave field. The interference of the wave reflection signal to the phase-locked loop improves the accuracy of the Doppler echo acquisition. The probe separately collects the Doppler echo signals without mutual interference. Each probe corresponds to an independent signal processor, and the processed signals are collected. Digital-to-analog conversion of signals on the same converter board. The upper computer is connected to the conversion board. The converter board is connected to the 4-20 mA circuit loop at the same time. The AD converted digital signal is processed by the FPGA, and the data is stored and locked through the EEPROM, including preamplification, AD sampling, waveform transformation, and then the signal is transmitted to the conversion board for signal conversion, and the FPGA is configured in an active serial mode.

Example 3

A microwave solid flow meter, the appearance of which is shown in FIG. The end of the detecting rod 1 is a measuring end face 4, and the microwave transceiver module inside the detecting rod 1 emits microwaves and receives reflections into the material tube through the measuring end face 4. Echo; a data processing module is included on the circuit board 3 inside the casing 2. The microwave transceiver module comprises a phase lock chip, a waveguide, a frequency sweep signal generator and a point frequency signal generator, wherein the frequency and power of the microwave transmission are adjustable. The data processing module includes an A/D analog-to-digital conversion chip, a filter downsampling chip, an FEPG chip, and an output chip, wherein the FEPG chip has built-in FFT transform and amplitude spectrum calculation functions.

Comparative example

The flow rate of alumina powder was measured in a temporary set up standpipe, and the flow rate of alumina powder was uniformly injected at a speed of 1 ton / hr in the upper part, using an electronic scale, a commercially available product MUTEC MF3000 and a SWR Solidflow microwave solid flow meter, and the microwave solid flow of the present invention. The flow measurement is performed, and the reading is performed at a fixed time interval. The results are as follows:

	30 minutes	60 minutes	90 minutes	120 minutes
Electronic scale	503kg	1002kg	1498kg	2007kg
MF3000	435kg	628kg	900kg	1048kg
Solidflow	473kg	790kg	1233kg	1356kg
This product	490kg	989kg	1505kg	1992kg

As can be seen from the above table, the precision of the product of the present invention is much higher than that of the existing microwave solid flowmeter.

The microwave solid flowmeter of the invention adopts an FPGA digital signal processing system, can measure and store the flow of materials online, and can establish a transport rule according to requirements. And according to the real-time flow of materials, the amount of additives can be controlled, the quality of the products can be stabilized, and the cost can be reduced. The on-line measurement is carried out by using a microwave solid flow meter, and the material conveying amount becomes clear and transparent, and the ratio can be adjusted at will, thereby achieving continuous operation of the system.

The specific embodiments herein are only a few typical embodiments of the present invention, but such description is not intended to limit the invention in any way, the microwave solid flow meter protected by the present claim. Both the signal processing method and the system are within the scope of the invention.

Claims (25)

1. A microwave solid flowmeter detection system comprises a Doppler echo acquisition module, a sensing plate, a conversion board and a host computer, wherein the sensing board comprises an A/D analog-to-digital conversion module, a filter downsampling module, and a signal Processing system; the conversion board is used to convert the digital signal into a current signal, and output current as a signal source of the display device.
2. The system of claim 1 wherein said signal processing system is an FPGA for time domain and frequency domain signal conversion, speed smoothing, constant false alarm processing, and flow value statistics.
3. The system of claim 2, wherein the I, Q analog signals containing the Doppler information collected by the high-precision chip are converted into digital signals as a signal source of the FPGA digital signal processing system.
4. The system of claim 1, wherein the Doppler echo acquisition module comprises a crystal oscillator, a phase locked loop, a CPLD, a transceiver integrated chip, and a microwave probe.
5. The system of claim 2, wherein the Doppler echo acquisition module is a radio frequency transceiver integrated structure, adopting an integrated transceiver chip for transmitting and receiving signals; and a phase locked loop inside the voltage control chip is stable. The carrier signal is transmitted through the waveguide, receives an echo signal containing a carrier wave and a Doppler frequency, and is orthogonally processed by the LNA and the mixer to filter out the carrier signal to generate an I and Q quadrature signal containing only Doppler information. For subsequent processing.
6. The system of claim 1 including an anti-aliasing filter for filtering and downsampling.
7. The system of claim 1, wherein the upper computer is coupled to the conversion board and the sensing board to control a working mechanism corresponding to the conversion board and the sensing board.
8. The system of claim 7 wherein the host computer sends instructions and parameters to control the signal processing system operating mechanism while receiving data for display.
9. A device for operating a microwave solid flowmeter detecting system according to claim 1, comprising a sensor body, an electrical box, and a host computer, wherein the electrical box contains a conversion board, the sensor body is connected to the probe, and the flow meter probe is fixed to be tested. The direction of the probe and solid flow on the wall of the solid flow line The angle is 15°<θ<90° or 90°<θ<165°, and the upper computer is connected to the conversion board.
10. The apparatus according to claim 9, wherein said probe is at an angle of 30 ° ≦ θ ≦ 60 °, more preferably 45 ° to the solid flow direction.
11. The apparatus of claim 9 wherein said probe is a multi-probe set, the number of probes being n, wherein n = 2, 3, 4, 5, 6, 7, ..., n, wherein n is an integer.
12. The apparatus according to claim 11, wherein said plurality of probes are arranged in a horizontal ring array, a vertical line array, and a circular vertical array.
13. The apparatus according to claim 11, wherein the probe separately collects Doppler echo signals without mutual interference, each probe corresponds to an independent signal processor, and the processed signals are collected on the same conversion board for signal. Digital to analog conversion.
14. The apparatus according to claim 9, wherein said sensor body has a columnar structure and internally includes a microwave transmitting device, a microwave receiving device, an A/D analog to digital conversion device, a filter downsampling device, an FFT transform, and an amplitude spectrum calculating device.
15. The apparatus of claim 14 wherein the microwave transmitting device is a variable frequency adjustable power microwave transmitting device.
16. The apparatus of claim 14 wherein the microwave emitting device comprises a phase locked chip.
17. The apparatus of claim 14 wherein the microwave transmitting means comprises a waveguide, a frequency sweep signal generator and a point frequency signal generator.
18. The apparatus according to claim 14, wherein said microwave transmitting means and microwave receiving means are integrated into a radio frequency transmitting and receiving integrated structure for transmitting and receiving microwave signals.
19. The apparatus of claim 9 further comprising a 4-20 mA circuit loop.
20. The apparatus according to claim 14, wherein the FFT transform and the amplitude spectrum calculation are implemented by an FPGA digital signal processor, and the FPGA digital signal processor and the microwave receiving device are connected The received microwave signal enters the FPGA digital signal processor through a digital to analog conversion device.
21. The apparatus of claim 9 further comprising an anti-aliasing filter for filtering and downsampling.
22. The apparatus of claim 21 wherein the FPGA is configured in an active serial mode, a passive serial mode, a JTAG mode.
23. A method for detecting solid flow by using a microwave solid flowmeter detection system according to claim 1, comprising the steps of: collecting Doppler echo; performing echo/A/D analog-to-digital conversion; and filtering the digital signal Downsampling; fast Fourier FFT calculation by digital signal processing system, calculation of amplitude spectrum; solid flow velocity and flow value parameters obtained by velocity spectrum; calibration processing, calibration of the relationship between solid flow value and velocity, will be obtained The value is converted to the corresponding current signal output for data display.
24. The method of claim 23 wherein said signal processing system is an FPGA.
25. The method according to claim 24, wherein the FPGA is used for time domain and frequency domain signal conversion, speed smoothing processing, constant false alarm processing, and flow value statistics.

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