CN103644955A - Differential-motion strain fiber Bragg grating suspension-type belt weigher - Google Patents

Abstract

The invention discloses a differential-motion strain fiber Bragg grating suspension-type belt weigher and relates to the technical field of weighing devices of a continuous flow material during flowing. The belt weigher includes a static beam, a weighing carrier roller, fiber Bragg gratings, cantilever beams of equal strength, dynamic beams, belt conveyor longitudinal beams and a signal processing device. The static beam is fixed between the two belt conveyor longitudinal beams. Load-carrying ends of the cantilever beams of equal strength are fixedly connected with the dynamic beams. Fixing ends of the cantilever beams of equal strength are fixed on the static beam between the conveyor longitudinal beams. The dynamic beams are fixed on a fixing base of the weighing carrier roller. A fiber Bragg grating is fixed at the center line of each of the upper and lower surfaces of the cantilever beams of equal strength. The fiber Bragg gratings are connected with the signal processing device through signal wires. The belt weigher is capable of measuring temperature and pressure at the same time and is high in electromagnetic interference resistant capability so that real-time accurate measurement of the belt weigher is realized.

Description

Differential strain type optical fiber Bragg raster-suspended belt scale

Technical field

The present invention relates to the device technique field that continuous flow material is weighed when flowing, relate in particular to a kind of differential strain type optical fiber Bragg raster-suspended belt scale.

Background technology

The belted electronic balance crane span structure of weighing is installed on and carries in frame, and when material is through out-of-date, metering carrying roller detects the weight of material on belt feeder, by leverage, in LOAD CELLS, produces a voltage signal that is proportional to belt load.On belt conveyer scale, having a LOAD CELLS to be contained in weighs on crane span structure, during work, the weight of material detecting on belt is sent into weighing instrument, by the rate signal of tachogenerator band conveyor, also send into weighing instrument simultaneously, instrument is carried out Integral Processing by rate signal and weighing-up wave, obtains instantaneous delivery and cumulative amount.Speed pickup is directly connected on major diameter speed measuring drum, and a series of pulses are provided, and each pulse represents a belt movement unit, and the frequency of pulse is proportional to belt speed.Weighing instrument receives signal from LOAD CELLS and speed pickup, draws an instantaneous delivery value and accumulating weight value, and show respectively by integral operation.

Belt conveyer scale mainly contains mechanical type and the large class of electronic type two.There is afterwards TTS type belt conveyer scale, TTS Novel series belted electronic balance product has adopted modelling measuring principle, belt claims multiparameter information fusion technology to make up the intrinsic defect of use " single-sensor ", many sensor locations, on the different characteristic point of band conveyor, have been formed to multi-sensor information sensory perceptual system from region angle; Utilize database technology from the state of the quantitative reflection weighing system of time domain angle.TTS type belted electronic balance has thoroughly solved the long-term and ubiquitous problems such as accuracy of belt scale, stability, expensive maintenance from the metering performance of belt conveyer scale own and belt conveyer scale ambient adaptability two aspects.Because the inverting element of suspended belt scale adopts resistance strain gage mostly, measuring accuracy is subject to the impact of electromagnetic interference (EMI).

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of differential strain type optical fiber Bragg raster-suspended belt scale, described belt conveyer scale can to temperature and pressure, measure simultaneously and anti-electromagnetic interference capability strong, realized the real-time Measurement accuracy of belt conveyer scale.

For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of differential strain type optical fiber Bragg raster-suspended belt scale, it is characterized in that: comprise static beam, weighing carrier roller, optical fiber Bragg raster, equi intensity cantilever, dynamic beam, band conveyor longeron and signal processing apparatus, described static beam is fixed between two band conveyor longerons, the force side of equi intensity cantilever is fixedly connected with dynamic beam, the stiff end of equi intensity cantilever is fixed on the static beam between conveyor longeron, dynamically the firm banking of beam and weighing carrier roller is fixed, upper along equi intensity cantilever, each fixes an optical fiber Bragg raster lower surface center line, optical fiber Bragg raster is connected with signal processing apparatus by signal wire.

Preferably, the both sides, front and back of described equi intensity cantilever are provided with parallel leaf spring, and one end of parallel leaf spring is fixedly connected with static beam, and the other end of parallel leaf spring is fixedly connected with dynamic beam, parallel leaf spring, static beam and dynamic beam form framed structure, and described equi intensity cantilever is positioned at described framework.

The beneficial effect that adopts technique scheme to produce is: described belt conveyer scale is separately fixed at the stiff end of equi intensity cantilever and free end on static beam and dynamic beam, optical fiber Bragg raster is fixed on equi intensity cantilever, by the amount of deflection of equi intensity cantilever being changed to the measurement converting to the centre wavelength displacement of optical fiber Bragg raster, realizes weighing in real time of belt conveyer scale.Utilization is pasted on the otherness of the Double fiber Bragg gratings pressure and temperature response on the upper and lower surface of equi intensity cantilever, when can realize temperature and pressure, measures.Because optical fiber Bragg raster is electrically insulating material, therefore have advantages of that anti-electromagnetic interference capability is strong, optical fiber Bragg grating sensor is applicable to the belt balance weighing in electromagnetic interference (EMI) situation, can realize Measurement accuracy.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.

Fig. 1 is the main TV structure schematic diagram of dismounting belt of the present invention;

Fig. 2 is the plan structure schematic diagram of dismounting belt of the present invention and weighing carrier roller;

Wherein: 1, static beam 2, weighing carrier roller 3, bolt 4, optical fiber Bragg raster 5, equi intensity cantilever 6, dynamic beam 7, parallel leaf spring 8, conveyor longeron 9, signal processing apparatus.

Embodiment

As shown in Figure 1-2, a kind of differential strain type optical fiber Bragg raster-suspended belt scale, dynamically beam 6 is connected with the firm banking of weighing carrier roller 2, the force side of equi intensity cantilever 5 is fixedly linked with dynamic beam 6, the stiff end of equi intensity cantilever 5 is fixed on static beam 1, along the upper and lower surface of equi intensity cantilever 5, each fixes an optical fiber Bragg raster 4, and optical fiber Bragg raster 4 use signal wires are connected with signal processing apparatus 9.

The fixing optical fiber Bragg raster 4 in upper and lower surface of described equi intensity cantilever 5 is positioned at position of center line, and equi intensity cantilever 5 two ends are with bolts to be fixed with static beam 1 and dynamic beam 6 respectively.During convey materials, material passes to dynamic beam 6 to the pressure of belt by weighing carrier roller 2, and dynamically beam 6 passes to power again equi intensity cantilever 5, and equi intensity cantilever 5 produces amount of deflection (deformation quantity) to be changed, thereby causes that optical fiber Bragg raster wavelength shift changes.

The principle that described belt conveyer scale is measured quality of material is: during mass transport, material passes to dynamic beam to the pressure of belt by weighing carrier roller, dynamically beam passes to equi intensity cantilever by pressure again, according to power, transmit known, during mass transport quality of material M and equi intensity cantilever free end the pass of stressed F be:

F=Mg 1）

Wherein g is acceleration of gravity.

Belt conveyer scale load causes equi intensity cantilever 5 free ends displacements, and optical fiber Bragg raster 4 is with equi intensity cantilever 5 deformation, if in measuring process temperature variation △ T, the wavelength-shift amount Δ λ B of the optical fiber Bragg raster 4 that load and temperature cause is:

△λ _B=(S _ε△ε+S _T△T)λ _B 2）

S wherein _εfor strain sensitive coefficient; S _Τfor temperature-sensitivity coefficient; △ ε is the displacement of equi intensity cantilever free end; △ T is temperature variation; λ _bcentered by wavelength.

The wavelength-shift of two optical fiber Bragg rasters that the upper and lower surface of equi intensity cantilever is pasted subtracts each other, and eliminates the impact of environment temperature:

△λ _B1,2=△λ _B1-△λ _B2=2S _ε△ελ _B 3）

Δ λ wherein _b1,2wavelength-shift difference for upper and lower surperficial two optical fiber Bragg rasters of pasting of equi intensity cantilever; Δ λ _b1with Δ λ _b2be respectively the wavelength-shift of two optical fiber Bragg rasters of pasting on the upper and lower surface of equi intensity cantilever.

The pass of equi intensity cantilever free end displacement △ ε and the suffered stress F of equi intensity cantilever free end is:

$\mathrm{\Δ\ϵ}=\frac{6\·F\·L}{E\·b_0\·h^2}---4)$

Wherein L, h are respectively length and the thickness of equi intensity cantilever; E is the Young modulus of equi intensity cantilever material; b ₀width for equi intensity cantilever stiff end.

By formula 4) substitution formula 3), the pass of the Bragg wavelength-shift of optical fiber Bragg raster and the suffered stress F of equi intensity cantilever free end is:

${\mathrm{\&Delta;\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="HDA0000428721570000011.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="B"\; filenames="HDA0000428721570000011.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}\mathrm{1,2}}=\frac{{12S}_{\mathrm{\&epsiv;}}{\mathrm{FL\&lambda;}}_B}{{\mathrm{Eb}}_0{h}^2}---5)$

By formula 1) substitution formula 5), the pass of quality of material M is when the Bragg wavelength-shift of optical fiber Bragg raster and mass transport:

${\mathrm{\&Delta;\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="HDA0000428721570000011.png"\; state="\{\{state\}\}">\; <figure-callout\; id="2"\; label="B"\; filenames="HDA0000428721570000011.png"\; state="\{\{state\}\}">B</figure-callout>\; </figure-callout>}\mathrm{1,2}}=\frac{12S_{\mathrm{\&epsiv;}}\mathrm{Mg}{\mathrm{L\&lambda;}}_B}{{\mathrm{Eb}}_0{h}^2}---6)$

Mathematical model while formula 6) having shown mass transport between quality of material M and optical fiber Bragg raster wavelength-shift, the quality of material in the time of just can calculating mass transport by the displacement of measuring optical fiber Bragg grating wavelength.

The equi intensity cantilever that the present embodiment adopts stainless steel material to make.

1, equi intensity cantilever, dimensional parameters is: L=250mm, h=5mm, b0=200mm;

2, equi intensity cantilever, material parameter is: Young ' the s modulus of 45# steel is E=200GPa;

3, the technical parameter of optical fiber Bragg raster is: centre wavelength B=1550.000nm, strain sensitive coefficient S _ε=0.78;

4, acceleration of gravity is: g=9.8N/Kg;

5, press accompanying drawing 2 configuration experiments;

6, with fiber grating analyser, obtain the Bragg wavelength of optical fiber Bragg raster;

7, according to formula 6), the Bragg wavelength-shift of optical fiber Bragg raster during to mass transport the response sensitivity of quality of material be:

$\frac{{\mathrm{\&Delta;\&lambda;}}_{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="HDA0000428721570000011.png"\; state="\{\{state\}\}">B</figure-callout>}\mathrm{1,2}}}{M}=\frac{{12S}_{\mathrm{\&epsiv;}}{\mathrm{gL\&lambda;}}_B}{{\mathrm{Eb}}_0{h}^2}---7)$

By known quantity substitution formula 7), theory is calculated and is shown, and the sensitivity of the optical fiber Bragg raster LOAD CELLS in this belt conveyer scale is 35.54pm/Kg.Therefore,, when the wavelength resolution of optical fiber Bragg raster (FBG) demodulator is 1pm, the resolution of this sensor is 0.028Kg.Comparative analysis result shows, the advantage such as this kind of differential strain type optical fiber Bragg raster-suspended belt weighing-appliance has high measurement resolution, and measuring error is little, reproducible.

Described belt conveyer scale is separately fixed at the stiff end of equi intensity cantilever and free end on static beam and dynamic beam, optical fiber Bragg raster is fixed on equi intensity cantilever, by the amount of deflection of equi intensity cantilever being changed to the measurement converting to the centre wavelength displacement of optical fiber Bragg raster, realizes weighing in real time of belt conveyer scale.Utilization is pasted on the otherness of the Double fiber Bragg gratings pressure and temperature response on the upper and lower surface of equi intensity cantilever, when can realize temperature and pressure, measures.Because optical fiber Bragg raster is electrically insulating material, therefore have advantages of that anti-electromagnetic interference capability is strong, optical fiber Bragg grating sensor is applicable to the belt balance weighing in electromagnetic interference (EMI) situation, can realize Measurement accuracy.

Applied specific case herein principle of the present invention and embodiment thereof are set forth, the explanation of above embodiment is just with helping understand method of the present invention and core concept thereof.It should be pointed out that for the person of ordinary skill of the art, can also carry out some improvement and modification to the present invention under the premise without departing from the principles of the invention, these improvement and modification also fall in the protection domain of the claims in the present invention.

Claims (2)

1. a differential strain type optical fiber Bragg raster-suspended belt scale, it is characterized in that: comprise static beam (1), weighing carrier roller (2), optical fiber Bragg raster (4), equi intensity cantilever (5), dynamic beam (6), band conveyor longeron (8) and signal processing apparatus (9), described static beam (1) is fixed between two band conveyor longerons (8), the force side of equi intensity cantilever (5) is fixedly connected with dynamic beam (6), the stiff end of equi intensity cantilever (5) is fixed on the static beam (1) between conveyor longeron (8), dynamically beam (6) is fixed with the firm banking of weighing carrier roller (2), upper along equi intensity cantilever (5), each fixes an optical fiber Bragg raster (4) lower surface center line, optical fiber Bragg raster (4) is connected with signal processing apparatus (9) by signal wire.

2. differential strain type optical fiber Bragg raster-suspended belt scale according to claim 1, it is characterized in that: the both sides, front and back of described equi intensity cantilever (5) are provided with parallel leaf spring (7), one end of parallel leaf spring (7) is fixedly connected with static beam (1), the other end of parallel leaf spring (7) is fixedly connected with dynamic beam (6), parallel leaf spring (7), static beam (1) and dynamic beam (6) form framed structure, and described equi intensity cantilever (5) is positioned at described framework.

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