CN112557420A - Probe of microwave moisture meter - Google Patents
Probe of microwave moisture meter Download PDFInfo
- Publication number
- CN112557420A CN112557420A CN201910919906.6A CN201910919906A CN112557420A CN 112557420 A CN112557420 A CN 112557420A CN 201910919906 A CN201910919906 A CN 201910919906A CN 112557420 A CN112557420 A CN 112557420A
- Authority
- CN
- China
- Prior art keywords
- moisture content
- moisture
- frequency
- signal
- value
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more
- G01N22/04—Investigating moisture content
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Control Of Conveyors (AREA)
Abstract
And (3) measuring the moisture by microwave, wherein the probe transmits a microwave signal, and an echo signal is obtained after the microwave signal is reflected by a measured material. And detecting the instantaneous difference between the echo and the transmitted signal, and calibrating to obtain the moisture content of the detected medium. In the environment where the conveyor is transporting material, the height of the material and the speed of the conveyor can greatly interfere with the measurement of the moisture value. By means of the doppler effect, two radar modules are used to transmit signals of the same frequency, maintaining a slight angle, which results in 2 doppler signals F1/F2, whose frequency spectra have a common overlap region on the frequency domain diagram and an intersection frequency Fk in the overlap region. The difference between the average powers of F1 and F2 and Fk was taken as the amount of change in moisture content. Taking the signal energy difference of F1/F2 as the height value of the material, and taking the height value as the compensation of the moisture content; by using Fk as the speed value of the conveyor belt and also as the compensation of the moisture content, a stable moisture value can be obtained.
Description
Technical Field
The invention relates to a detection device, in particular to a probe of a microwave moisture meter.
Background
There are two difficulties in measuring the moisture content of the material being conveyed on the conveyor, 1 being the constant change in the height of the material being conveyed, which results in a change in the reflected energy of the microwaves, and 2 being the change in the speed of the conveyor which also results in a change in the reflected energy of the microwaves. Without compensation for changes in height and velocity, accurate material moisture values are not possible.
Disclosure of Invention
The water content in any solid material can be used for determining the water content in the medium according to the action and electromagnetic wave signal reflection or secondary scattering propagation information.
And (3) microwave moisture measurement, namely transmitting a specifically modulated frequency signal through an antenna, and reflecting the signal by a measured material to generate an echo signal. Comparing the energy loss of the two signals, because the energy of the echo signal changes under the influence of the moisture content of the medium, the instantaneous difference between the echo signal and the emission signal is detected, and the moisture content of the detected medium can be obtained through the standard moisture calibration table scale.
In the context of a conveyor belt conveying material, the measurement needs to account for variations in the frequency and energy of the doppler effect caused by material uniformity and material movement.
Based on the consideration, the method and the device for measuring the Doppler effect adopt 2 radar modules to transmit signals with the same frequency, and the signals are reflected back to be received again after being transmitted to a target.
The two radar modules transmit at the same signal frequency, and the two signals are transmitted along the direction of belt travel or in opposite directions and are maintained at a slight angle, such as 10 degrees.
This results in 2 doppler signals F1/F2, whose spectra have a common overlap region on the frequency domain plot and an intersection frequency Fk (the magnitude of which can be measured and confirmed by a frequency identifier) within the overlap region.
The difference between the average powers of F1 and F2 and Fk was taken as the amount of change in moisture content.
And taking the signal energy difference of F1/F2 as the height variation of the material conveying belt as the compensation of the moisture content.
Fk is used as the speed value of the conveyor belt and also as compensation for the moisture content.
The beneficial effect of this patent does: by adopting the mode to obtain the probe of the microwave moisture meter, the influence of the height of materials on the conveying belt and the speed of the conveying belt can be synchronously compensated while moisture signals are obtained, the detection precision is greatly improved, and the cost is not increased.
Drawings
FIG. 1 is a frequency domain plot of a microwave moisture meter probe signal.
Fig. 2 is a schematic view of a radar module installation.
1 radar module A, 2 are radar module B, 3 are the conveyer belt, 4 are the material.
Detailed Description
Referring to fig. 2, a radar module A1 and a radar module B2 are installed side by side and fixed above a conveyor belt 3, and form a slight angle. The 2 radar modules are fixed above the conveyor belt 3 and emit signals of the same frequency, and the signals are reflected back to be received again after being emitted to the material 4.
Referring to fig. 1, radar module A1 generates doppler signal F1, and radar module B2 generates doppler signal F2, the frequency spectrums of which have a common overlapping region on the frequency domain map and an intersection frequency Fk in the overlapping region (the size of the intersection frequency can be measured and confirmed by a frequency identifier).
And taking the difference between the average power of F1 and F2 and Fk as the variation of the moisture content, and taking the difference between the signal energy of F1/F2 as the variation of the height of the material conveying belt as the compensation of the moisture content. Fk is used as the speed value of the conveyor belt and also as compensation for the moisture content.
The specific embodiments are illustrative of the invention and are not intended to limit the scope of the invention. Various changes and modifications can be made by one skilled in the art without departing from the spirit and scope of the invention, and all equivalent technical solutions are within the scope of the invention, which is defined by the claims.
Claims (1)
1. A microwave moisture meter probe is characterized in that: 2 radar modules are adopted to transmit signals with the same frequency, the 2 radar modules keep a tiny angle, such as an angle of 10 degrees, and the signals are reflected back to be received again after being transmitted to a target; this results in 2 doppler signals F1/F2, whose spectra have a common overlap region on the frequency domain plot and an intersection frequency Fk in the overlap region; taking the difference between the average power of F1 and F2 and Fk as the change amount of the moisture content; taking the difference of the signal energy of F1/F2 as the height variation of the material conveying belt and the compensation of the moisture content; taking Fk as the speed value of the conveyor belt and also as the compensation of the moisture content; a stable moisture value can be obtained.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910919906.6A CN112557420A (en) | 2019-09-26 | 2019-09-26 | Probe of microwave moisture meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910919906.6A CN112557420A (en) | 2019-09-26 | 2019-09-26 | Probe of microwave moisture meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112557420A true CN112557420A (en) | 2021-03-26 |
Family
ID=75030227
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910919906.6A Pending CN112557420A (en) | 2019-09-26 | 2019-09-26 | Probe of microwave moisture meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112557420A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101975783A (en) * | 2010-08-30 | 2011-02-16 | 清华大学 | Measurement device for simultaneously measuring ash content and water content |
| CN102401896A (en) * | 2011-08-26 | 2012-04-04 | 湖南湘依铁路机车电器股份有限公司 | Method for calculating Doppler signal spectrum |
| CN105372649A (en) * | 2015-11-03 | 2016-03-02 | 黄中瑞 | Railroad locomotive speed measurement method based on adaptive double-path sampling filtering |
| CN106872490A (en) * | 2017-03-10 | 2017-06-20 | 四川莱源科技有限公司 | Moisture content tester based on radar |
| CN108459032A (en) * | 2018-05-25 | 2018-08-28 | 吉林农业大学 | A kind of device and measurement method of dual probe difference type micro-wave on-line measurement moisture content |
-
2019
- 2019-09-26 CN CN201910919906.6A patent/CN112557420A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101975783A (en) * | 2010-08-30 | 2011-02-16 | 清华大学 | Measurement device for simultaneously measuring ash content and water content |
| CN102401896A (en) * | 2011-08-26 | 2012-04-04 | 湖南湘依铁路机车电器股份有限公司 | Method for calculating Doppler signal spectrum |
| CN105372649A (en) * | 2015-11-03 | 2016-03-02 | 黄中瑞 | Railroad locomotive speed measurement method based on adaptive double-path sampling filtering |
| CN106872490A (en) * | 2017-03-10 | 2017-06-20 | 四川莱源科技有限公司 | Moisture content tester based on radar |
| CN108459032A (en) * | 2018-05-25 | 2018-08-28 | 吉林农业大学 | A kind of device and measurement method of dual probe difference type micro-wave on-line measurement moisture content |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP2902799B1 (en) | Doppler radar test system | |
| US6470734B2 (en) | Method and arrangement for measuring fluid | |
| US7889119B2 (en) | Radial gap measurement on turbines | |
| US7861600B2 (en) | Apparatus for ascertaining and/or monitoring fill level and/or flow of a medium | |
| AU2002304283B2 (en) | Apparatus and method for microwave determination of at least one physical parameter of a substance | |
| US7586435B1 (en) | Radar level gauge system using a waveguiding structure with periodically arranged reference impedance transitions | |
| US5969666A (en) | Radar-based method of measuring the level of a material in a container | |
| US9551606B2 (en) | Determining a level and flow speed of a medium | |
| US6466168B1 (en) | Differential time of flight measurement system | |
| CN106338317B (en) | System and method for measuring signal propagation velocity in liquid or gaseous medium | |
| US4161731A (en) | Thickness measurement system | |
| US20100000314A1 (en) | Arrangement for fill level measurement | |
| US10295393B2 (en) | Guided wave radar level gauge system with dual transmission line probes for dielectric constant compensation | |
| US20150103628A1 (en) | Movable system for measuring a content of a bin | |
| US10816385B2 (en) | Radar level gauge | |
| EP3264073B1 (en) | Measuring device | |
| CN104345308A (en) | Vehicle detector and method for measuring vehicle distance and vehicle speed | |
| CN104199019A (en) | Continuous wave detector testing system | |
| US4659982A (en) | Microwave apparatus and method of operation to determine position and/or speed of a movable body or discontinuity or change in a material | |
| Yusupov et al. | Analysis of common errors and methods of calibration of ultrasonic level meter | |
| KR20150034091A (en) | Bimaterial interface position measurement system | |
| WO1994017373A1 (en) | Procedure for determining material flow rate | |
| CN112557420A (en) | Probe of microwave moisture meter | |
| CN102055536A (en) | Reflector antenna delay measurement method | |
| RU2504740C1 (en) | Method of measurement of fluid level in container |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20210326 |
|
| WD01 | Invention patent application deemed withdrawn after publication |