CN101363750B - Correcting method of weigh without counter poise for large tonnage material level electronic scale - Google Patents

Abstract

The invention relates to a large-tonnage level electronic scale and a non-weight weighing correction method. The electronic scale body is provided with a charging barrel bin, and four or more uniformly distributed support bearing lug seats. A weighing sensor with a cylindrical structure is installed below each support bearing lug seat; the weighing sensor is installed on a base; a spherical surface is formed on the upper end of the weighing sensor and connected with a pressure with an end surface being an concave spherical surfaced; an upper press plate and a lower press plate are connected with the scale body and the base; an adjusting shim is placed on the upper loaded press plate so as to adjust the installation height of each sensor. The non-weight weighing connection method is suitable for the weighing correction of a plurality of resistance strain sheet type weighing sensors in parallel connection, and comprises the steps of calculating an output signal value of a weighing sensor, figuring out a consistent correction coefficient of a weighing instrument and working out the correction efficient of the weighing instrument. The invention has the advantages of simple structure, convenient installation, high weighing precision, great cost performance and convenient weighing correction.

Description

The correcting method of weigh without counter poise of large tonnage material level electronic scale

Technical field

The present invention relates to a kind of electronic scales, relate in particular to a kind of large-tonnage feed bin formula material level electronic scale and correction of weighing method.

Background technology

The iron and steel metallurgy enterprise of China, particularly large-scale steel plant have all taked superseded small furnace, primary converter, the conversion of newly-built large blast furnace and converter, the scale effect can reach energy-saving and emission-reduction, enhances productivity, and promotes the purpose of product quality.Current newly-built blast furnace is all at 2000m³More than, supporting with it raw material storage, batching feed bin all maximize.The large-tonnage feed bin that in chemical industry, food and thermal power generation industry, needs raw material storage, batching equally.Along with the raising of enterprise to product quality, consumption of raw materials, cost management, measuring requirement to this large-tonnage feed bin is more and more higher, we are not only the height that will understand material level in the feed bin, also will finish the batching of material according to manufacturing technique requirent, this just needs a kind of device that can accurately measure weight of material in the feed bin.

In the past the large-tonnage feed bin was only carried out the online detection of material level in the feed bin, so very low to Testing requirement, whether people can overflow when feeding in raw material in feed bin as long as understand the height of material level in the feed bin, whether material is empty in the feed bin, whether needs to replenish information such as material.The most frequently used material level detection mode has ultrasound wave material level measuring method and radar type level gauging mode, and the principle of work and the mounting means of these two kinds of measuring methods are basic identical, and their principal feature is as follows:

The material level measuring method of these two kinds of metering systems is to be issued to the height that the time of returning draws material in the feed bin by measuring ultrasound wave or radar wave, thereby determines the height of material level.As calculating the weight of measuring material, then come calculated weight by volume and proportion.The measuring error of material level is very big, and measured material level is uneven by material and the influence of angle of rest (repose), is difficult to record correct material level, and the volume that therefore calculates gained thus is also incorrect, influenced by material moisture, granularity etc., and last gained weight error will be bigger.The installation site of ultrasonic material level detection unit must be at the top of feed bin, and installation, difficult in maintenance adds the charging aperture that feeding bin top is material, for charging aperture design has increased difficulty like this.Therefore these measuring methods can only detect the material level situation in the feed bin, can not be according to carrying out Charge Mixture Control with the measurement data.

Summary of the invention

The objective of the invention is: a kind of dependable performance is provided, and the accuracy of detection height can satisfy and measure the bin-level situation and control the large tonnage material level electronic scale that the batching operation requires;

Another object of the present invention is: a kind of correcting method of weigh without counter poise of proofreading and correct conveniently, satisfying the accuracy requirement of control batch weighing is provided.

Above-mentioned technical matters of the present invention is mainly solved by following technical proposals:

Large tonnage material level electronic scale

Technical scheme of the present invention is that the employing gravimetric method detects the weight of material in the control feed bin, so just can also regard feed bin as the bunker scale of a super large-scale, and the scale body is regarded as in the barrel storehouse.On same surface level more than the center of gravity of barrel storehouse, be provided with four or more equally distributed support pad seat, be separately installed with LOAD CELLS below each support pad seat, described LOAD CELLS is installed on the pedestal, and base height is higher than distance between support pad seat and the discharging opening; There is sphere the upper surface of described LOAD CELLS, and the center of described sphere and the center of LOAD CELLS are same center.Form electronic scales with the LOAD CELLS more than 4 or 4, can alleviate the local pressure of feed bin bases such as floors.

As preferably, described LOAD CELLS is the resistance-strain chip LOAD CELLS of pole structure.

As preferably, fixedlying connected with pedestal below by lower platen of described LOAD CELLS joined by top board and support pad seat above.

As preferably, it is the pressure head of spill sphere that the lower end is arranged between described LOAD CELLS and the top board, and the spherical diameter of pressure head is greater than the spherical diameter of sensor upper surface, and described pressure head is connected with top board.Pressure head is a concave spherical surface, just in time be buckled on the upper end sphere of LOAD CELLS, and certain small rocking arranged, when guaranteeing that outside multiple factor is exerted oneself slightly deflection, small rocking can take place by outer forced direction in sensor on sphere, make the sphere summit center line of alignment sensor all the time.

As preferably, be provided with the adjustment pad between described support pad seat and the top board, adjust the setting height(from bottom) of each sensor, make it after the installation on same surface level.

Correcting method of weigh without counter poise

The correction of weighing of large-tonnage feed bin formula electronic scales is a more scabrous problem, calculate by less feed bin, as range of weighing is 0～100t, for the precision that guarantees to proofread and correct generally need load standard test weight (FS is a full scale) more than the 50%FS, will on feed bin, load the 50t standard test weight equably like this, feed bin is not a platform scale, it is impossible loading so many counterweights on feed bin, and the scale of 100t range is belong to minimum a kind of in the large-tonnage feed bin, and the hundreds of ton is generally all arranged.

Large-tonnage feed bin formula electronic scales all is the technology scale in the production run, and it is just passable to reach 0.1%FS to the requirement of weighing precision, just might adopt correcting method of weigh without counter poise to proofread and correct this electronic scales according to this condition.

The output signal value of LOAD CELLS when loading rated load can be by calculating, in weighing instrument when design, is behind selected A/D converter, the A/D conversion value of exporting under specified input signal also is known, can obtain correction coefficient according to these parameters by suitable calculating, correction coefficient is changed into and LOAD CELLS quantity by formula, the sensor input sensitivity, as long as the corresponding relation of the specified range of sensor is in use input pickup quantity, transducer range, sensor average sensitivity and the weighing instrument displayed value under rated load just can be finished no counterweight correction of weighing.

No counterweight correction of weighing condition, all LOAD CELLS require to adopt the method that is connected in parallel, and LOAD CELLS is a resistance strain-gauge transducer.

According to the principle of work of strain gauge load cell, the output signal value when sensor loads is directly proportional with the output sensitivity of sensor and the driving voltage of sensor.The quantity of the resistance-strain chip LOAD CELLS that connects when electronic scales is many, and sensor adopts when being connected in parallel, and the sensor output sensitivity should be the average output sensitivity of many sensors, and the specified output signal value of sensor is calculated as follows:

A, LOAD CELLS output signal Vcfs:

Vcfs＝S×V ·················(1)

$S=\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn}/n\·\·\·\·\·\·\·\·\·\left(2\right)$

Wherein: Vcfs-sensor output signal, the mV of unit

The average output sensitivity of S-sensor, the mV/V of unit

The V-transducer excitation voltage, the V of unit

Each sensor output sensitivity of Sn-, the mV/V of unit

The n-number of sensors

With (2) formula substitution (1) formula, then

$\mathrm{Vcfs}=(\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn}/n)\×V\·\·\·\·\·\·\·\·\·\left(3\right);$

B, weighing instrument consistance correction coefficient DJNc:

Increase an input signal consistance correction link during weighing instrument design, when dispatching from the factory weighing instrument is carried out proofreading and correct in the factory, promptly under identical input signal, weighing instrument converts input signal to identical A/D conversion yardage, and the error of each instrument cubicle is less than 0.01%FS.For specific weighing instrument after determining A/D converter, A/D conversion value output under the identical input signal situation is consistent relatively, but because of the discreteness of device, certain difference is arranged still, eliminate this difference and will carry out the consistance correction the A/D conversion value.

Be calculated as follows:

M＝AD×DJNc ·················(4)

AD＝Vifs×C ·················(5)

Wherein: the M-consistance is proofreaied and correct the A/D conversion yardage of back output, unitary code

The A/D conversion value of AD-A/D converter under specified input signal, unitary code

Correction coefficient in the DJNc-factory

The specified input signal of Vifs-, the mV of unit

Every millivolt of input signal A/D converter of C-value, unitary code/mV

With (5) formula substitution (4) formula and arrangement, then

DJNc＝M/(Vifs×C) ···············(6)；

The correction coefficient DJN of c, weighing instrument:

No counterweight correction of weighing is the correction coefficient that will calculate weighing instrument according to known parameters, a known parameter of electronic scales is the specified range (W) of scale, LOAD CELLS quantity (n), the output sensitivity of each LOAD CELLS (Sn), the specified range (Wcfs) of sensor and the weighing instrument displayed value (Dfs) under rated load.

The correction factor calculation of weighing instrument is as follows:

DJN＝Dfs/M1 ···············(7)

M1＝(Vi/Vifs)×M ···············(8)

Vi＝[W/(Wcfs×n)]×Vcfs ··········(9)

Wherein: the correction of weighing coefficient of DJN-instrument

The displayed value yardage of Dfs-weighing instrument under rated load is 1000t as specified range, and displayed value requires to be promptly to differentiate 0.1t by 1000.0t, and then the value of Dfs is 10000.

The M1-sensor loads the A/D conversion yardage under the rated load, unitary code

Vi-is the sensor output signal value when loading specified range, the mV of unit

The specified range of W-scale, the t of unit

The specified range of Wcfs-sensor, the t of unit

With (9) formula substitution (8) formula and arrangement, then

M1＝(W×M×Vcfs)/(Wcfs×n×Vifs)·······(10)

With (10) formula substitution (7) formula and arrangement, then

DJN＝(Dfs×Wcfs×n×Vifs)/(W×M×Vcfs)·····(11)

Again with (3) formula substitution (11) formula and arrangement, then

$\mathrm{DJN}=(\mathrm{Dfs}\×\mathrm{Wcfs}\×n\×\mathrm{Vifs}\×n)/(W\×M\×V\×\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn})\·\·\left(12\right).$

Weighing instrument calculates correction of weighing coefficient DJN automatically according to known conditions, just can realize no counterweight correction of weighing.It is easy, simple to operate that this bearing calibration user grasps, and can solve the correction of weighing problem of large-tonnage feed bin.

Therefore, the invention has the beneficial effects as follows: large tonnage material level electronic scale, have simple in structure, easy for installation, maintenance is convenient, weighing precision height, long service life, and have the fabulous ratio of performance to price.

Adopt correcting method of weigh without counter poise, overcome prior art large-tonnage electronic scales and need carry out the deficiency of correction of weighing, and proofreaied and correct very convenient with a large amount of standard test weights.

Description of drawings

Accompanying drawing 1 is a kind of structural front view of the present invention;

Accompanying drawing 2 is storehouse material vertical views of Fig. 1;

Accompanying drawing 3 is that LOAD CELLS is installed front view;

Accompanying drawing 4 is pressing plate planimetric maps;

Accompanying drawing 5 is resistance-strain chip LOAD CELLS and method of attachment figure.

Embodiment

Below by embodiment also in conjunction with the accompanying drawings, technical scheme of the present invention is further described in detail.

Embodiment:

The large tonnage material level electronic scale example

Material level electronic scale scale structure as shown in Figure 1 and Figure 2,barrel storehouse 3 directly is shelved on theLOAD CELLS 1 by loadingsupport pad seat 5,support pad seat 5 status requirements are chosen relative higher position, in barrel storehouse center of gravity with the upper part.Because the specification of feed bin is bigger, the present invention adopts 4 important actor formula LOAD CELLS to form electronic scales, alleviates the local pressure of feed bin to the basis.Among the figure, 4 is discharge mechanism, and 2 is pedestal.

LOAD CELLS installation diagram as shown in Figure 3, Figure 4,LOAD CELLS 1 upper end is asphere 11, link to each other withpressure head 7, be a concave spherical surface below the pressure head, spherical radius is greater than the sphere ofLOAD CELLS 1 upper end, and the two just in time is buckled together, and certain small rocking arranged, when guaranteeing that outside multiple factor is exerted oneself slightly deflection, small rocking can take place by outer forced direction insensor 1 on sphere, make the sphere summit center line of alignment sensor all the time.Upper and lowerpressing plate 8,6 links to each other withpedestal 2 withscale body 1 respectively, and the adjustment pad of placing on thetop board 8 ofloading 9 is adjusted the setting height(from bottom) of each sensor, makes it after the installation on same surface level.

No counterweight correction of weighing

As shown in Figure 5, the applicable elements of no counterweight correction of weighing is to have many resistance-strain chip LOAD CELLS, and LOAD CELLS adopts and is connected in parallel, and many table scales retransmit sensor and weigh instrument with a table scale.1 is the LOAD CELLS of resistance-strain chip among the figure.

No counterweight correction of weighing will calculate correction coefficient DJN by known conditions.The key of problem is the proportionate relationship that will know between input signal and the AD conversion yardage.When weighing instrument designs, concerning the deviser, input signal and AD conversion yardage are known conditions, but because of the parameter discrete of components and parts, all certain difference can be arranged, the AD converter difference of this species diversity because of selecting for use to each instrument, the difference size all can be different, as select integrated AD converter for use, then difference can be a little bit smaller, and is just bigger as the AD converter difference of forming with the apportion element.The unification calibration function that will to increase a functional module when designing be weighing instrument for this reason produces the input signal of standard with standard signal generator before instrument is dispatched from the factory, correcting mode carries out unification and proofreaies and correct automatically then.

This standard procedure is as follows:

Suppose that the AD that every millivolt of input signal of this instrument converts to changes yardage between 20500～21000 yards, then generally every millivolt of input signal consistance can be proofreaied and correct is the M1=20000 sign indicating number, and input reference signal is 0～30mV.

Return Z-operation when 1, importing 0mV, make to be shown as 0, the AD conversion yardage AD0=1000 when instrument writes down 0mV automatically.

2, input 30mV standard signal, the AD conversion yardage AD1=618900 when instrument writes down 30mV automatically.

4, carry out the consistance correct operation, instrument is calculated the consistance correction coefficient automatically.The AD conversion yardage of answering standard to arrive when knowing input 30mV input signal because of the deviser, this example is M=20000 * 30=600000 sign indicating number.

The instrument computing formula is as follows:

M＝(AD1-AD0)×DJNc

DJNc=M/ (AD1-AD0)=300000/ (618923-1000)=0.9709948 (single precision floating datum computing)

Checking:

(618923-1000)×0.9709948＝600000.0198004

Data are 600000 after doing the computing that rounds up behind the radix point.

Just finished the consistance correction for weighing instrument like this, between AD conversion yardage and the input signal a fixing proportionate relationship has just been arranged, this example is M1=20000 sign indicating number/mV.

Data in required calculating of next step person's of being to use practical operation and the input instrument.

For a fixed electronic scales, LOAD CELLS quantity and correlation parameter all are known number, and the weight that weighing instrument need show also is known parameters, and transducer excitation voltage also is a fixing known parameters, as V=10V, need go out the correction of weighing coefficient by these calculation of parameter now.

The first step is by the average output sensitivity of operator's hand computation sensor, each sensor all has a certificate, there is one to be output sensitivity mV/V in the certificate, i.e. the magnitude of voltage of per 1 volt of transducer excitation voltage sensor output when sensor loads specified range.

$S=\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn}/n$

As: four sensors are arranged, and output sensitivity is respectively 1.512mV/V (S1), 1.514mV/V (S2), 1.493mV/V (S3), 1.498mV/V (S4), then

S＝(1.512+1.514+1.493+1.498)/4＝1.50425

The second step weighing instrument calculates the sensor input signal under the specified range automatically

As the specified range of each sensor is W=500t, and instrument is shown as Dfs=1000.0t, and the transducer excitation voltage of weighing instrument is V=10V.Number of sensors is the n=4 platform.

Vi＝S×V×(Dfs/(W×n))＝1.50425×10×(1000/(500×4))＝7.52125mV

The automatic calculation correction coefficient of the 3rd step weighing instrument

Dfs＝M1×Vi×DJN

DJN＝Dfs/(M1×Vi)＝10000/(20000×7.52125)＝0.06647831

Checking:

Dfs＝20000×7.52125×0.06647831＝9999.99978175

Data are 10000 after doing the computing that rounds up behind the radix point.Computing shows 1000.0t after adding 1 radix point.

Calculated examples:

The specified input signal of weighing instrument is 30mV (Vcfs), it is 600 that A/D conversion output valve will be sought unification when dispatching from the factory, 000 yard (M), but because the discreteness of components and parts, actual every millivolt of input signal A/D converter value is 20100 yards (C), when weighing instrument dispatches from the factory weighing instrument is carried out consistance and proofreaies and correct, and making the output valve when specified input signal is 600,000 yard, try to achieve correction coefficient in the factory by (6) formula.

DJNc＝M/(Vifs×C)＝600000/(30×20100)＝0.99502

The specified range of material level electronic scale is 1000t (W), weighing instrument shows 1000.0t when loading 1000t, then Dfs is 10000, selecting 4 (n) specified ranges for use is the LOAD CELLS of 500t (Wcfs), the sensor output sensitivity is respectively 1.512mV/V (S1), 1.514mV/V (S2), 1.493mV/V (S3), 1.498mV/V (S4), and the transducer excitation voltage of weighing instrument is 10V (V).By (12) formula calculation correction coefficient.

$\mathrm{DJN}=(\mathrm{Dfs}\×\mathrm{Wcfs}\×n\×\mathrm{Vifs}\×n)/(W\×M\×V\×\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn})$

＝(10000×500×4×30×4)/[1000×600000×10×(1.512+1.514+1.493+1.498)]＝0.0664783。

The operator need import following parameter to weighing instrument during practical operation:

1, the average output sensitivity S=1.50425 that calculates;

2, the specified range Wcfs=500 of sensor

3, number of sensors n=4

4, the specified range Dfs=1000.0 of electronic scales.

Other parameter is intrinsic in the formula in the formula, does not need input.

The present invention is applicable to the electronic scales installation and the correction of weighing of large-sized silos such as metallurgy, chemical industry, food.

Claims (1)

1. the correcting method of weigh without counter poise of a large tonnage material level electronic scale, has barrel storehouse (3), on same surface level more than the center of gravity of barrel storehouse, be provided with four or more equally distributed support pad seat (5), be separately installed with resistance-strain chip LOAD CELLS (1) below each support pad seat, described resistance-strain chip LOAD CELLS is installed on the pedestal (2), and base height is higher than distance between barrel storehouse support pad seat and the discharging opening; There is sphere (11) upper surface of described resistance-strain chip LOAD CELLS (1), and the center of described sphere and the center of LOAD CELLS are same center; Described resistance-strain chip LOAD CELLS (1) electrically connects with weighing instrument;

It is characterized in that: adopt between the resistance-strain chip LOAD CELLS to be connected in parallel, concrete bearing calibration is:

A, LOAD CELLS output signal Vcfs calculate:

Vcfs＝S×V ………………(1)

$S=\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn}/n\·\·\·\left(2\right)$

Wherein: Vcfs-sensor output signal, the mV of unit

The average output sensitivity of S-sensor, the mV/V of unit

The V-transducer excitation voltage, the V of unit

Each sensor output sensitivity of Sn-, the mV/V of unit

The n-number of sensors

With (2) formula substitution (1) formula, then

$\mathrm{Vcfs}=(\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn}/n)\×V\·\·\·\left(3\right);$

B, weighing instrument consistance correction coefficient DJNc calculate:

M＝AD×DJNc ………………(4)

AD＝Vifs×C ………………(5)

Wherein: the M-consistance is proofreaied and correct the A/D conversion yardage of back output, unitary code

The A/D conversion value of AD-A/D converter under specified input signal, unitary code

Correction coefficient in the DJNc-factory

The specified input signal of Vifs-, the mV of unit

Every millivolt of input signal A/D converter of C-value, unitary code/mV

With (5) formula substitution (4) formula and arrangement, then

DJNc＝M/(Vifs×C)………………(6)；

The correction coefficient DJN of c, weighing instrument calculates:

DJN＝Dfs/M1 ………………(7)

M1＝(Vi/Vifs)×M?………………(8)

Vi＝[W/(Wcfs×n)]×Vcfs………(9)

Wherein: the correction of weighing coefficient of DJN-instrument

The displayed value yardage of Dfs-weighing instrument under rated load is 1000t as specified range, and displayed value requires to be promptly to differentiate 0.1t by 1000.0t, and then the value of Dfs is 10000

The M1-sensor loads the A/D conversion yardage under the rated load, unitary code

Vi-is the sensor output signal value when loading specified range, the mV of unit

The specified range of W-scale, the t of unit

The specified range of Wcfs-sensor, the t of unit

With (9) formula substitution (8) formula and arrangement, then

M1＝(W×M×Vcfs)/(Wcfs×n×Vifs)………(10)

With (10) formula substitution (7) formula and arrangement, then

DJN＝(Dfs×Wcfs×n×Vifs)/(W×M×Vcfs)……(11)

Again with (3) formula substitution (11) formula and arrangement, then

$\mathrm{DJN}=(\mathrm{Dfs}\×\mathrm{Wcfs}\×n\×\mathrm{Vifs}\×n)/(W\×M\×V\×\underset{n=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sn})\·\·\left(12\right).$

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