CN1439870A - Resonant densimeter with longitudinal vibration mode - Google Patents
Resonant densimeter with longitudinal vibration mode Download PDFInfo
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- CN1439870A CN1439870A CN 03111234 CN03111234A CN1439870A CN 1439870 A CN1439870 A CN 1439870A CN 03111234 CN03111234 CN 03111234 CN 03111234 A CN03111234 A CN 03111234A CN 1439870 A CN1439870 A CN 1439870A
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- longitudinal vibration
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Abstract
A resonance density meter using longitudinal vibration mode is composed of slender resonator, fixing plate, permanent magnet whose magnetic field has same direction as that resonator axis, resonance exciter which is a coil wound on resonator, vibration pick-up, and signal processing circuit. It can be used for powdered solid in high pressure condition. Its advantage is small size.
Description
Technical field: the resonant mode densitometer that the present invention relates to a kind of resonant type densitometer, particularly a kind of longitudinal vibration mode.
Background technology: the resonant mode densitometer is a kind of novel density measuring instrument, the densitometric resonant mode sensitive element of resonant mode in the past mostly adopts resonatron, responant diaphragm or tuning fork to make, utilize electronic feedback system to replenish resonant energy, resonator is maintained resonant condition, when measured medium contact resonator, because the effect of near the dielectric surface tension force this resonator, absorption affinity etc. makes measured medium also produce vibration, this quality that is equivalent to resonator increases, and causes its natural resonance frequency to change.Density of medium difference, the size that its resonance frequency changes are also different.Utilize the corresponding relation of Media density and resonator resonance frequency, can obtain the density of measured medium.Its advantage is: (1) can be installed on the pipeline, and fluid density is carried out online continuous coverage; (2) measuring accuracy height, good resolution; (3) the output frequency signal antijamming capability is strong, but the distant signal transmission; (4) good stability, repeatability is good.Yet also there are some weakness in present existing vibration tube formula densitometer, flows through in resonatron inside as liquid, resonatron is thicker, and resonatron adopts the transverse bending vibration pattern, and vibrator must be produced on the both sides of vibrating tube, make the volume of instrument become big, can't use at small space; Resonatron must be connected as a single entity with fluid pipeline, and check is each time demarcated and must be dismantled pipeline; The tube wall of resonatron is thinner in the prior art, its stiff end must adopt the damping fixed sturcture with certain rigidity and quality, prevent leaking and the reduction of Q value (quality factor) of resonant energy, therefore, the influence of resonatron liquid body pressure and viscosity is bigger, therefore it can't use for high viscosity liquid or under big pressure environment, and it can only be used for liquids and gases usually, can't be used for the density measure of powdered object.In sum, mainly there is following problem in existing resonant mode densitometer: 1, the resonatron of prior art use must be connected as a single entity with fluid pipeline, and resonatron is thicker, and check is each time demarcated and must be dismantled pipeline; 2, prior art all adopts the lateral vibration mode of resonatron, and vibrator must be produced on the both sides of resonatron, makes the volume of instrument become big, can't use at little annular space.3, the influence of the resonatron liquid body pressure of prior art is bigger, can't use under big pressure environment; 4, prior art can not be used for powdered object; 5, prior art can not be used for level gauging.
Summary of the invention: for solve the volume that existing resonant mode densitometer exists big, under big pressure environment, can't use, can not be used for powdered object and measure, can not be used for problems such as level gauging, the invention provides a kind of resonant mode densitometer that adopts longitudinal vibration mode.Resonant mode densitometer of the present invention comprises resonator 1, clamped plate 2, permanent magnet 3, vibrator 4, vibro-pickup 5, signal processing circuit 7, the middle part of longilineal resonator 1 length direction is fixed in the through hole 2-1 of clamped plate 2, permanent magnet 3, vibrator 4, vibro-pickup 5 and signal processing circuit 7 are installed in the top of clamped plate 2, the magnetic direction of permanent magnet 3 is identical with the axis K direction of resonator 1, vibrator 4 is one group of coil that are wrapped on the resonator 1, the gap 4-1 of guaranteed resonator 1 free vibration between vibrator 4 and the resonator 1.In use the bottom of resonator 1 is inserted in the measured medium and can carry out density measure; This device can also laterally be installed on the sidewall of the container that material is housed, and just can carry out the measurement of material level.The natural frequency of resonator 1 of the present invention is
In the formula: k is the rigidity of vibrational system, and m is the quality of vibrational system.The natural frequency that should be pointed out that resonator 1 is a learning concept, and the resonance frequency of system is always different with natural frequency, and difference depends on the damping of system.Be not difficult to find out that by following formula any physical change that can change the rigidity k or the quality m of vibrational system all will make resonator 1 Natural Frequency of Vibration change.When being full of measured medium, variation has all taken place in the rigidity of resonatron and quality and damping, and the natural frequency of resonator 1 is changed when resonator 1 outside (perhaps outside and inner), measures this and changes, and can obtain the density of measured matter.After the amplifier of natural frequency variable signal in signal processing circuit 7 that vibro-pickup 5 picks up enough amplifies, again relevant voltage is fed back to vibrator 4, transfer exciting force to balance damping force (comprising viscous damping and other damping), like this, just, can keep resonator 1 and near its natural frequency, make continuous vibration.Though the viscosity of fluid also has certain influence to the resonance frequency of resonatron, the increase of fluid viscosity, resonance frequency f can slightly descend.This is because the cause that the apparent density of resonator increases along with viscosity.In the Newtonian fluid mechanics, the increment Delta ρ of this apparent density
xAnd satisfy following formula between the increment Delta C of vibration damping ratio: Δ C ∝ f Δ ρ
x, therefore, can try to achieve Δ C according to the variable quantity of vibration amplitude.So along with the increase of viscosity, the apparent density increment that is produced can compensate with following formula, principle of work of the present invention that Here it is.Specifically be summarized as follows: the density of measured object is adjusted the natural frequency of resonator 1, and the vibration of resonator 1 is kept by frequency modulation amplifier in the signal processing circuit 7, thereby the amount of densities of measured object is changed into frequency output.Constitute a closed loop frequency modulation autovibration system as for frequency modulation amplifier in frequency amplifier, resonator 1, vibro-pickup 5, vibrator 4 and the signal processing circuit 7, the frequency signal corresponding with density exported in the two-wire system mode by the leading-out terminal 8 of socket 9.This densitometer is having purposes widely aspect the production run control.Can be used for the output in the gas production and the control of quality, in food and medicine industry, the production run that can be used for syrup, yogurt, milk, cheese, vegetable oil product is carried out density control.In chemical industry, can be used for the waste liquid of protein, starch, metabisulfite solution, sodium silicate, coal tar and discharging etc.In petroleum industry, in the transportation of crude oil production and petroleum products, be used for the test of petroleum products and down-hole oil density.Therefore densitometer of the present invention becomes plug in construction owing to have the resonator 1 of slim-lined construction, has characteristics such as volume is little, high pressure resistant, can carry out the two-wire system long-distance transmissions.Resonant mode densitometer of the present invention is specially adapted to the online density measuring of crawl space, and this densitometer has that volume is little, high pressure resistant, the advantage of anti-vibration; Resonant mode densitometer of the present invention is the resonant mode densitometer that adopts longitudinal vibration mode, and resonance frequency has very high resolution up to tens KHz; Densitometer vibration tube of the present invention more tiny (diameter is several millimeters), convection cell does not have resistance in flowing liquid, can not produce the pressure loss; Modified of the present invention can be used for the density measure of pressed powder; Modified of the present invention can be used for the density measure of gas; The present invention can be made into portable densimeter, is used for the on-the-spot density measurement to some liquid; The present invention can be used for the level gauging of granular solids material.
Description of drawings: Fig. 1 is the structural representation of embodiment one, Fig. 2 is the mounting structure synoptic diagram of densitometer in pipeline of embodiment two, Fig. 3 is the structural representation of embodiment three, Fig. 4 is the densitometric mounting structure synoptic diagram of embodiment four, Fig. 5 is the structural representation of embodiment five, and Fig. 6 is the mounting structure synoptic diagram of embodiment six.
Embodiment one: consult Fig. 1, present embodiment is made up of resonator 1, clamped plate 2, permanent magnet 3, vibrator 4, vibro-pickup 5, shell 6, signal processing circuit 7, leading-out terminal 8, socket 9.Shell 6 be fixed on clamped plate 2 above, resonator 1 is the thin-wall circular tube of the hollow of being made by elastic alloy, for the fluid to be measured sealing, the lower end of pipe is designed to enclosed construction.The middle part of resonator 1 is fixed in the through hole 2-1 of clamped plate 2.Resonator 1 and clamped plate 2 are connected as one by vacuum brazing.Permanent magnet 3, vibrator 4, vibro-pickup 5 and signal processing circuit 7 are installed in the inside of shell 6.Vibrator 4 is one group of coil that are wrapped on the resonator 1, the gap 4-1 of guaranteed resonator 1 free vibration between vibrator 4 and the resonator 1.Vibro-pickup 5 is another group coils that are wrapped on the resonator 1, the gap 5-1 of guaranteed resonator 1 free vibration between vibro-pickup 5 and the resonator 1.Permanent magnet 3 is hollow-core constructions and is set in vibro-pickup 5 and the outside of vibrator 4 that the magnetic direction of permanent magnet 3 is identical with the axis K direction of resonator 1.Socket 9 is installed in the top of shell 6, and leading-out terminal 8 is installed in the socket 9, and leading-out terminal 8 connects signal processing circuit 7 through lead, and signal processing circuit 7 connects vibrator 4 and vibro-pickup 5 through lead respectively.
Embodiment two: consult Fig. 2, what present embodiment and embodiment one were different is that the through hole 11 that connects before and after having on the tube wall of resonator 1 lower end is provided with dividing plate 10 at the inside and the clamped plate 2 sustained height places of resonator 1.The effect of through hole 11 is used for eliminating fluid to be measured pressure, avoids the static pressure of resonator liquid body to produce strain.Dividing plate 10 is used for isolating fluid to be measured, it separates the upper and lower part of resonator, though it can be subjected to the static pressure of liquid and produce strain, because it is to be on the node of resonator vibrates with clamped plate 2, so can the vibration of resonatron not exerted an influence.In use this densitometer is installed on the pipeline 12, pipeline 12 inside are inserted in the bottom of resonator 1.Other composition is identical with embodiment one with annexation.
Embodiment three: consult Fig. 3, what present embodiment and embodiment one were different is, resonator 1 is the solid body of rod, and the lower end of body of rod formula resonator 1 can be taper.This densitometer can be used for inserting in the powder, measures the density of pressed powder.Other composition is identical with embodiment one with annexation.
Embodiment four: consult Fig. 4, what present embodiment and embodiment one were different is, the outside surface of tubular resonator 1 bottom is connected with damping sheet 13, so that in measuring casing 14 during gas density, is used to improve the sensitivity of the resolution gas density of resonator 1.Other composition and annexation and
Embodiment one is identical.
Embodiment five: consult Fig. 5, what present embodiment and embodiment one, two, three, four were different is, vibro-pickup 5 is accelerometers, and vibro-pickup 5 is installed in the top of resonator 1.Other composition is identical with embodiment one, two, three, four with annexation.
Embodiment six: consult Fig. 6, what present embodiment and embodiment one were different is, densitometer is installed on the bulkhead of material bin 15, and resonator 1 lower end is stretched in the material bin 15, can be used for like this measuring whether material reaches height in the storehouse, this densitometer can be used as level-sensing device and uses.
Claims (8)
1, a kind of resonant mode densitometer that adopts longitudinal vibration mode, it comprises resonator (1), clamped plate (2), permanent magnet (3), vibrator (4), vibro-pickup (5), signal processing circuit (7), the middle part that it is characterized in that longilineal resonator (1) length direction is fixed in the through hole (2-1) of clamped plate (2), permanent magnet (3), vibrator (4), vibro-pickup (5) and signal processing circuit (7) are installed in the top of clamped plate (2), the magnetic direction of permanent magnet (3) is identical with the axis K direction of resonator (1), vibrator (4) is one group of coil that is wrapped on the resonator (1), the gap (4-1) of guaranteed resonator (1) free vibration between vibrator (4) and the resonator (1).
2, a kind of resonant mode densitometer that adopts longitudinal vibration mode according to claim 1 is characterized in that resonator (1) is the thin-wall circular tube by the hollow of elastic alloy making.
3, a kind of resonant mode densitometer that adopts longitudinal vibration mode according to claim 2, the through hole (11) that connects before and after it is characterized in that having on the tube wall of resonator (1) lower end is provided with dividing plate (10) at the inside and clamped plate (2) the sustained height place of resonator (1).
4, a kind of resonant mode densitometer that adopts longitudinal vibration mode according to claim 2 is characterized in that the outside surface of tubular resonator (1) bottom is connected with damping sheet (13).
5, a kind of resonant mode densitometer that adopts longitudinal vibration mode according to claim 1 is characterized in that resonator (1) is the solid body of rod.
6, according to claim 1,2,3,4 or 5 described a kind of resonant mode densitometers that adopt longitudinal vibration mode, it is characterized in that vibro-pickup (5) is another group coil that is wrapped on the resonator (1), the gap (5-1) of guaranteed resonator (1) free vibration between vibro-pickup (5) and the resonator (1).
7, a kind of resonant mode densitometer that adopts longitudinal vibration mode according to claim 6 is characterized in that permanent magnet (3) is hollow-core construction and is set in vibro-pickup (5) and the outside of vibrator (4).
8, according to claim 1,2,3,4 or 5 described a kind of resonant mode densitometers that adopt longitudinal vibration mode, it is characterized in that vibro-pickup (5) is an accelerometer, vibro-pickup (5) is installed in the top of resonator (1).
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CN 03111234 CN1439870A (en) | 2003-03-19 | 2003-03-19 | Resonant densimeter with longitudinal vibration mode |
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CN 03111234 CN1439870A (en) | 2003-03-19 | 2003-03-19 | Resonant densimeter with longitudinal vibration mode |
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Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100386606C (en) * | 2005-07-18 | 2008-05-07 | 杨尚明 | Electromagnetic type bin level meter |
CN102749266A (en) * | 2012-07-19 | 2012-10-24 | 青岛澳邦量器有限责任公司 | Fluid property measuring device and fluid density measuring method |
CN104101556A (en) * | 2014-08-11 | 2014-10-15 | 范明军 | Resonant liquid densimeter structure |
CN104155209A (en) * | 2014-08-11 | 2014-11-19 | 范明军 | Resonant liquid densitometer driver |
CN104181079A (en) * | 2014-09-04 | 2014-12-03 | 北京天辰博锐科技有限公司 | Density sensor |
WO2014201710A1 (en) * | 2013-06-18 | 2014-12-24 | 广州天禾自动化实业有限公司 | Sensor for detecting property of fluid |
CN109115653A (en) * | 2018-09-26 | 2019-01-01 | 重庆科技学院 | A kind of tuning fork resonance crude oil water content measuring device and its measurement method |
CN109444617A (en) * | 2018-12-27 | 2019-03-08 | 国网河南省电力公司洛阳供电公司 | A kind of voltage transformer harmonic elimination apparatus tester with quick detection mounting structure |
CN114062192A (en) * | 2021-11-11 | 2022-02-18 | 四川泛华航空仪表电器有限公司 | Frequency-selecting gain conversion circuit and working method thereof |
-
2003
- 2003-03-19 CN CN 03111234 patent/CN1439870A/en active Pending
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100386606C (en) * | 2005-07-18 | 2008-05-07 | 杨尚明 | Electromagnetic type bin level meter |
CN102749266A (en) * | 2012-07-19 | 2012-10-24 | 青岛澳邦量器有限责任公司 | Fluid property measuring device and fluid density measuring method |
WO2014201710A1 (en) * | 2013-06-18 | 2014-12-24 | 广州天禾自动化实业有限公司 | Sensor for detecting property of fluid |
CN104101556A (en) * | 2014-08-11 | 2014-10-15 | 范明军 | Resonant liquid densimeter structure |
CN104155209A (en) * | 2014-08-11 | 2014-11-19 | 范明军 | Resonant liquid densitometer driver |
CN104181079A (en) * | 2014-09-04 | 2014-12-03 | 北京天辰博锐科技有限公司 | Density sensor |
CN109115653A (en) * | 2018-09-26 | 2019-01-01 | 重庆科技学院 | A kind of tuning fork resonance crude oil water content measuring device and its measurement method |
CN109444617A (en) * | 2018-12-27 | 2019-03-08 | 国网河南省电力公司洛阳供电公司 | A kind of voltage transformer harmonic elimination apparatus tester with quick detection mounting structure |
CN109444617B (en) * | 2018-12-27 | 2023-08-25 | 国网河南省电力公司洛阳供电公司 | Voltage transformer harmonic elimination device tester with rapid detection and installation structure |
CN114062192A (en) * | 2021-11-11 | 2022-02-18 | 四川泛华航空仪表电器有限公司 | Frequency-selecting gain conversion circuit and working method thereof |
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