CN205484139U - A cylindrical nuclear magnetic resonance sensor for detecting moisture in soil - Google Patents
A cylindrical nuclear magnetic resonance sensor for detecting moisture in soil Download PDFInfo
- Publication number
- CN205484139U CN205484139U CN201620019151.6U CN201620019151U CN205484139U CN 205484139 U CN205484139 U CN 205484139U CN 201620019151 U CN201620019151 U CN 201620019151U CN 205484139 U CN205484139 U CN 205484139U
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- magnet
- magnetic resonance
- radio
- soil moisture
- cylindrical core
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Abstract
The utility model discloses a cylindrical nuclear magnetic resonance sensor for detecting moisture in soil, include and produce along the main magnet of axial static magnetic field 10, matching circuit 8 and the RF coil 5 of production along radial spurious radiation's radio frequency field in the space, matching circuit is connected with the RF coil electricity, the magnetic field that main magnet produced and the magnetic field quadrature of RF coil production. The utility model discloses small, portable can reduce simultaneously the work load of boring, only need the very little hole in aperture alright measure in order realizing.
Description
Technical field
This utility model relates to a kind of sensor detecting moisture, is specifically related to a kind of cylindrical nuclear-magnetism for detecting soil moisture
Resonance sensor.
Background technology
Soil moisture is the important parameter in the fields such as agricultural sciences, Meteorological Science and hydrological science.Agriculturally, soil is agricultural
The basic document produced, shallow table soil moisture plays vital effect to the growth of crops, is the most also to judge agricultural ring
The important indicator in border.Meteorological with in water conservancy, shallow table soil moisture measure the distribution for earth surface effective energy, latent heat and
The exchange of sensible heat and air and runoff and the distribution research aspect infiltrated play an important role.
At present, detect both at home and abroad the method for shallow table soil moisture and mainly have following several big class: soil outward appearance digital palpation for examination of trauma, weighting method after dried,
Tonometry, neutron diffusion method, time domain reflectometry, frequency domain bounce technique, standing wave ratio method, remote sensing method, nuclear magnetic resonance method etc..
(1) soil outward appearance digital palpation for examination of trauma is according to outward appearance, quality and the perception of soil, by soil and the contrast of given chart, rule of thumb
The water content of soil is judged.The method needs certain experience accumulation, practice have shown that, the soil water judged by digital palpation for examination of trauma
Content water content actual with soil is divided to differ about ± (10%～15%).
(2) weighting method after dried is to survey mass water content of soil, common are calorstat oven drying method, infrared baking method and ethanol combustion
Burning method etc..In the world, oven drying method is considered as to measure the standard method of soil water content.But the shortcoming of the method is the brightest
Aobvious: to dry and need the longer time, it is a kind of metering system damaging to soil, it is impossible to fixed point long term monitoring.
(3) tonometry tonometer formula soil moisture sensor measures some soil water content.Tension force is in respect of a water-filling
Pipeline, one is the ceramic head of hollow, and other end is vacuum instrumentation.Ceramic head is in close contact with soil, in tonometer closed conduct
Water by ceramic head enter soil, produce tension force.The Tensity size that the drying and watering cycle of soil produces can be read by vacuum meter, enters
And indirectly determine soil moisture content.Its measurement scope is affected relatively big by soil property, and is easily affected by multiple soil physico-chemical characteristic, this
The measuring speed of outer the method is the fastest.
(4) neutron diffusion method utilizes neutron soil moisture tester to measure the water content in soil.Its principle is: fast neutron and thing
Matter effect can change direction and off-energy, forms decay and becomes slow neutron, the decay of generation because of in measured object water content different and different.
This method is not suitable for the moisture measurement for little scope soil sample, and equipment price is expensive, and disposable input is big, if shielding is not simultaneously
Put in place, radiation hazradial bundle can be caused.
(5) time domain reflectometry measures the dielectric constant of aqueous soil, thus determines the water content of soil.Its disadvantage is to set
Standby expensive and circuit is complicated, measured value also suffers from being affected by temperature, unit weight, soil property.
(6) frequency domain bounce technique is also a kind of to utilize the dielectric property of soil to the method determining soil water content.The method is uncomfortable
For measuring containing powder, the grains of sand and the soil of cosmid.
(7) high-frequency signal that standing wave ratio method utilizes HF signal generator to send travels to soil probe along transmission line, due to probe
Impedance is not mated with transmission line impedance, and incidence wave superposes formation standing wave with echo on the transmission line, by measuring transmission line outfan
Standing-wave ratio reflect the moisture content of soil.Standing wave ratio method is easily affected by soil salt, and certainty of measurement is the highest.
(8) remote sensing method utilizes the electromagnetic characteristics of object, by the electromagnetic wave of observed objects, thus identifies the ring of object and existence thereof
Border condition.This is a kind of large-range measuring method of macroscopic view, and its fine degree can not measure soil moisture content with other far away
Method is compared.
(9) nuclear magnetic resonance method is a kind of by detecting the content of Hydrogen Proton, thus indirectly can to contain the moisture in soil
Amount carries out detecting a kind of method.The equipment of existing Nuclear Magnetic Resonance Measurement soil moisture has a shortcoming the biggest to be exactly the most stupid
Weight, does not use machinery to be difficult to operate.
Utility model content
In view of this, the purpose of this utility model is to provide a kind of cylindrical core magnetic resonance sensors for detecting soil moisture.
The purpose of this utility model is realized by such technical scheme, a kind of cylindrical nuclear-magnetism for detecting soil moisture
Resonance sensor, is included in space and produces the main magnet 10 of static magnetic field vertically, match circuit 8 and produce radially
The radio-frequency coil 5 of the radio-frequency field of radiation, described match circuit electrically connects with radio-frequency coil；The magnetic field of described main magnet generation and radio frequency
The magnetic field orthotropic that coil produces.
Further, described main magnet includes upper magnet, center magnet and lower magnet three part, and the magnet of each part can be by single
Or the magnet composition of multiple formed objects, three part magnets stack successively, and the direction of magnetization is axially.
Further, the radius of described center magnet is less than upper magnet, and the radius of center magnet is less than lower magnet simultaneously.
Further, the radius of described upper magnet is equal to the radius of lower magnet.
Further, described radio-frequency coil 5 is arranged at around center magnet.
Further, described radio-frequency coil includes that multiple subcoil is in series.
Further, described subcoil is formed around to identical coils connected in series by two-layer.
Further, described sensor also includes the magnet bore 2 for placing main magnet.
Further, described sensor also includes that insulation spacer 4, described insulation spacer are arranged between radio-frequency coil and center magnet.
Owing to have employed technique scheme, this utility model has the advantage that
This utility model volume is little, it is simple to carry, and simultaneously can reduce the workload burrowed, it is only necessary to the least hole, aperture is the most permissible
Realize measuring.
Accompanying drawing explanation
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with accompanying drawing this utility model made into
The detailed description of one step, wherein:
Fig. 1 provides sensor and the 3D schematic diagram of target area for this utility model；
Fig. 2 provides sensor internal structural representation for this utility model；
Fig. 3 provides sensor internal structure disassembly diagram for this utility model；
Fig. 4 provides the profile of sensor internal structure for this utility model；
Fig. 5 provides sensor main magnet schematic diagram for this utility model；
Fig. 6 provides the main magnetic field distribution in the XOY plane of target area for this utility model；
Fig. 7 provides the tiling figure of radio-frequency coil for this utility model；
Fig. 8 provides coil relative signal-to-noise ratio curve on a circumference in the XOY plane of target area for this utility model.
Detailed description of the invention
Below with reference to accompanying drawing, preferred embodiment of the present utility model is described in detail；Should be appreciated that preferred embodiment is only
In order to this utility model being described rather than in order to limit protection domain of the present utility model.
Fig. 1 provides sensor and the 3D schematic diagram of target area for this utility model, in Fig. 2 provides sensor for this utility model
Portion's structural representation, Fig. 3 provides sensor internal structure disassembly diagram for this utility model, and Fig. 4 provides sensor for this utility model
The profile of internal structure, Fig. 5 provides sensor main magnet schematic diagram for this utility model, and Fig. 6 provides target for this utility model
Main magnetic field distribution in the XOY plane of region, Fig. 7 provides the tiling figure of radio-frequency coil for this utility model, and Fig. 8 is that this practicality is new
Type provides coil relative signal-to-noise ratio curve on a circumference in the XOY plane of target area.
As it can be seen, this utility model provides a kind of cylindrical core magnetic resonance sensors for detecting soil moisture, this sensing
Device can detect the moisture in outside soil.
Cylindrical core magnetic resonance sensors that this utility model embodiment provided is explained in detail below.
Fig. 1 is the 3D schematic diagram of sensor and target area, and in figure, 11 is the sensor being wrapped in water-proof jacket, and 12 is target
Region, 7 is the joint of connecting coaxial cable.Sensor can measure the moisture in sensor periphery certain area soil, during measurement
Need to burrow in soil, measure in then sensor being penetrated into hole.
Fig. 2 is sensor internal structural representation, and Fig. 3 is sensor internal structure disassembly diagram, and Fig. 4 is sensor internal structure
XOZ profile, each label one_to_one corresponding in Fig. 2, Fig. 3 and Fig. 4, in order to the structure of clearer display sensor internal.Figure
In, 1 is upper cover plate, and 2 is magnet bore, and 3 is wire casing, and 4 is insulation spacer, and 5 is radio-frequency coil, and 6 is lower cover, and 7 is same
Shaft cable joint, 8 is match circuit, and 9 is water-proof jacket, and 10 is main magnet.
A kind of cylindrical core magnetic resonance sensors for detecting soil moisture include main magnet, magnet bore, upper cover plate, lower cover,
Match circuit, insulation spacer, radio-frequency coil and waterproofing guaranteeding jacket.
The main magnet of described nmr sensor produces static magnetic field vertically in space, and radio-frequency coil is by three sub-coils connected in series
Forming, produce the radio-frequency field radially radiated, radio-frequency field is orthogonal with static magnetic field, to realize the measurement of NMR signal.
Fig. 5 is main magnet structure, is made up of the samarium cobalt permanent magnet body of three pieces of cylindrical low-temperature coefficients, three pieces of magnets (i.e. upper magnet,
Center magnet, lower magnet) direction of magnetization is axially, and the most coaxially puts, two pieces of magnets being relatively large in diameter at upper and lower two ends,
A diameter of 20mm, height is 15mm；The less magnet in one footpath is placed in centre, a diameter of 12mm, and height is 20mm.
Magnet bore, is used for placing main magnet, and its external shape is similar with the External Characters of main magnet part, approximates dumbbell shaped, middle
The part (i.e. middle magnet portion) of depression places insulation spacer, and insulation spacer is outside places radio-frequency coil.The magnetic at upper magnet place
Body cavity part is longer than lower magnet place magnet bore section, is used for placing match circuit.
Described match circuit is circular PCB, is arranged on the inner side of upper cover plate, faces inside magnet bore, externally
Less than match circuit.
Upper cover plate, lower cover and magnet bore form airtight cavity.Upper cover plate installs match circuit in the face of the one side (inner side) of magnet bore
And be encapsulated in magnet bore, in the face of extraneous one side (outside) installs coaxial fitting to be connected with external equipment, lower cover
Plate is used in one end of lower magnet and acts the effect closing magnet；Coaxial fitting is installed outside upper cover plate, connects with coaxial cable and pass
Sensor and instrument；Coaxial cable connects sensor and measuring instrument；Described upper cover plate, lower cover are cylindrical Ti Alloy Cover Plate,
Equivalently-sized, Ti Alloy Cover Plate can make sensor keep certain mechanical strength to be enclosed in by match circuit simultaneously and interior shield the external world
The interference of environment electromagnetics signal.
Insulation spacer thickness 4mm, its effect is spaced apart to radio-frequency coil and magnet bore, weakens eddy current effect to radio-frequency field
Impact.
Fig. 6 is the main magnetic field distribution in the XOY plane of target area, it can be seen that main field equipotential line is concentric circular distribution, target
Region internal diameter is 20mm, and external diameter is 25mm.
Fig. 7 is the tiling figure of radio-frequency coil, and coil is formed by arc length spaced series such as three subcoils, each subcoil by two-layer around
Forming to identical coils connected in series, live width is 0.8mm, and the overall size of radio-frequency coil is 122.2mm*18.5mm, and radio-frequency coil is used
Flexible print circuit is made, and bending in the form of a ring, is attached to outside insulation spacer.Radio-frequency coil is made up of several subcoils, often
The structural parameters of individual subcoil are identical, and circumferentially etc. arc length is spacedly distributed, and is serially connected, sends between each subcoil
Radio-frequency (RF) magnetic field direction identical.
Its effect of described waterproofing guaranteeding jacket is to prevent the moisture penetration in soil to sensor internal, shortens the life-span of sensor, or
Person causes sensor internal short circuit, initiating failure, damages sensor or measuring instrument.
Fig. 8 be radio-frequency coil be the relative signal-to-noise ratio curve on 25mm circumference at target area XOY plane inside radius, on curve
The excitation area of smooth part correspondence coil.
The foregoing is only preferred embodiment of the present utility model, be not limited to this utility model, it is clear that the technology of this area
Personnel can carry out various change and modification without deviating from spirit and scope of the present utility model to this utility model.So, if originally
These amendments of utility model and modification belong within the scope of this utility model and equivalent technologies thereof, then this utility model is also intended to bag
Change and including modification containing these.
Claims (9)
1. the cylindrical core magnetic resonance sensors being used for detecting soil moisture, it is characterised in that: it is included in space and produces vertically
The main magnet (10) of static magnetic field, match circuit (8) and produce the radio-frequency coil (5) of radio-frequency field radially radiated,
Described match circuit electrically connects with radio-frequency coil；The magnetic field orthotropic that the magnetic field that described main magnet produces produces with radio-frequency coil.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 1, it is characterised in that: described
Main magnet includes upper magnet, center magnet and lower magnet three part, and the magnet of each part can be by single or multiple formed objects
Magnet forms, and three part magnets stack successively, and the direction of magnetization is axially.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 2, it is characterised in that: described
The radius of center magnet is less than upper magnet, and the radius of center magnet is less than lower magnet simultaneously.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 3, it is characterised in that: described
The radius of upper magnet is equal to the radius of lower magnet.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 3, it is characterised in that: described
Radio-frequency coil (5) be arranged at around center magnet.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 5, it is characterised in that: described
Radio-frequency coil includes that multiple subcoil is in series.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 6, it is characterised in that: described
Subcoil is formed around to identical coils connected in series by two-layer.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 1, it is characterised in that: described
Sensor also includes the magnet bore (2) for placing main magnet.
Cylindrical core magnetic resonance sensors for detecting soil moisture the most according to claim 5, it is characterised in that: described
Sensor also includes insulation spacer (4), and described insulation spacer is arranged between radio-frequency coil and center magnet.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620019151.6U CN205484139U (en) | 2016-01-08 | 2016-01-08 | A cylindrical nuclear magnetic resonance sensor for detecting moisture in soil |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620019151.6U CN205484139U (en) | 2016-01-08 | 2016-01-08 | A cylindrical nuclear magnetic resonance sensor for detecting moisture in soil |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205484139U true CN205484139U (en) | 2016-08-17 |
Family
ID=56665600
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620019151.6U Expired - Fee Related CN205484139U (en) | 2016-01-08 | 2016-01-08 | A cylindrical nuclear magnetic resonance sensor for detecting moisture in soil |
Country Status (1)
| Country | Link |
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| CN (1) | CN205484139U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106645253A (en) * | 2016-12-22 | 2017-05-10 | 重庆大学 | Unilateral nuclear magnetic resonance sensor and nuclear magnetic resonance method for measuring soil moisture |
| CN106770417A (en) * | 2017-01-05 | 2017-05-31 | 浙江大学 | Rape drought diagnosis method and device based on nuclear magnetic resonance machine people |
| CN108459041A (en) * | 2018-03-26 | 2018-08-28 | 重庆大学 | A kind of nmr sensor for multi-region domain measurement |
| CN108776317A (en) * | 2018-06-12 | 2018-11-09 | 重庆大学 | A kind of cylindrical core magnetic resonance probe |
-
2016
- 2016-01-08 CN CN201620019151.6U patent/CN205484139U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106645253A (en) * | 2016-12-22 | 2017-05-10 | 重庆大学 | Unilateral nuclear magnetic resonance sensor and nuclear magnetic resonance method for measuring soil moisture |
| CN106645253B (en) * | 2016-12-22 | 2018-03-02 | 重庆大学 | Unilateral nmr sensor and magnetic nuclear resonance method for soil moisture measurement |
| CN106770417A (en) * | 2017-01-05 | 2017-05-31 | 浙江大学 | Rape drought diagnosis method and device based on nuclear magnetic resonance machine people |
| CN108459041A (en) * | 2018-03-26 | 2018-08-28 | 重庆大学 | A kind of nmr sensor for multi-region domain measurement |
| CN108776317A (en) * | 2018-06-12 | 2018-11-09 | 重庆大学 | A kind of cylindrical core magnetic resonance probe |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20160817 Termination date: 20170108 |