CN103994896B - A kind of computational methods of asphalt mixing vibrosieve efficiency - Google Patents

Abstract

The present invention relates to the computational methods of a kind of screening efficiency, it is specifically related to the computational methods of a kind of asphalt mixing vibrosieve efficiency, purpose is in that to consider to mix the situation of grain class distribution, reflection indeed vibrations riddler makes truth, carry out the calculating of the screening efficiency of multilayer screen cloth, the technical scheme adopted is: the productivity of counting yield and the granularmetric composition of total pan feeding and product, obtain each screen layer oversize material, the particle size fraction content of siftage material, the screening process that can reflect vibrosieve really is calculated according to total efficiency formula, calculate respectively particle size fraction in each layer pan feeding be smaller in size than the material of this layer of screen mesh size account for pan feeding at the corresponding levels percentage ratio and, in each layer screen cloth siftage particle size fraction be smaller in size than the material of this layer of screen mesh size account for pan feeding at the corresponding levels percentage ratio and, and particle size fraction is smaller in size than the material of this layer of screen mesh size and accounts for the percentage ratio sum of pan feeding at the corresponding levels in each layer screen cloth oversize.

Description

A kind of computational methods of asphalt mixing vibrosieve efficiency

Technical field

The present invention relates to the computational methods of a kind of screening efficiency, be specifically related to the computational methods of a kind of asphalt mixing vibrosieve efficiency.

Background technology

In construction of the highway, asphalt mixing plant vibrosieve directly controls to enter the hot doses in each thermal material storehouse and material grating, is the important step affecting asphalt mixture gradation precision, and the height of its screening efficiency directly affects the quality of whole highway. The weight of undersized product that screening efficiency actually obtains when being screening with enter to sieve the contained grade weight ratio less than screen size in material. The computational methods of the asphalt mixing Vibration Screen component efficiency adopted at present are mainly by following two:

Method (one): the computational methods that national standard " JT/T270-2002 forces batch (-type) Colophonium lavatory to close material mixing plant " adopts: the computing formula of screening efficiency is:

${\mathrm{\η}}_s=\frac{g_1}{g_0}\×100\%$

In formula: η_sScreening efficiency, %;

g₀Sample gross mass, g;

g₁By measuring, g.

According to method (), Multilayer vibrating screen measures sample by measuring the ratio with sample gross mass after sieving certain period, be the screening efficiency of vibrosieve. Adopt and there is problems in that in this way

[1] the method is inconsistent about the learning concept of screening efficiency with sieving machine, it is impossible to quote further in other Theoretical Calculation;

[2] situation that in vibrosieve, each layer compass screen surface oversize and siftage raw meal particle size level mix is not accounted for.

Method (two): site test computational methods:

The fine particle stage material first measured in the percentage ratio a% of fine fraction weight in original fines and oversize accounts for the percentage by weight c% of oversize typically by test method for laboratory and factory, now fine accounts for the b% of undersize, then calculates the actual screening efficiency of screen(ing) machine with aggregate efficiency formula (2).

${\mathrm{\η}}_s=\frac{(b-a)(a-c)\×100}{a(b-c)(1-a)}\×100\%$

Calculate the screening efficiency of screen cloth, it is necessary to obtain a, b, c these three parameter value by the actual method weighed, namely must obtain quality and the grade composition of each screen layer material accurately. In reality produces, the method Problems existing is adopted to have:

[1] under the continuous large-tonnage condition of production of reality, it is impossible to obtain each compass screen surface oversize material, the weight of siftage material and particle size fraction percentage ratio by weighing;

[2], when quantitative test, when screen cloth exceedes three layers, siftage weight of material and particle size fraction percentage ratio are difficult to measure;

[3] quantitative test condition and reality have produced difference continuously, and its screening efficiency calculated can not reflect the truth that vibrosieve works.

Summary of the invention

In order to solve the problems of the prior art, the present invention proposes a kind of situation considering that screen cloth mixes grain class distribution, continuously big yield production is obtained in that each oversize material, the quality of siftage material and grain class distribution ratio, reflection indeed vibrations riddler makes truth, it is possible to carry out the computational methods of the asphalt mixing vibrosieve efficiency of the screening efficiency mensuration of multilayer screen cloth.

In order to realize above goal of the invention, the technical solution adopted in the present invention comprises the following steps:

1) the productivity γ of the M kind product obtained after calculating M-1 layer bolting_i(i=1,2 ..., M), namely account for the percentage ratio of total pan feeding, and obtain total pan feeding and the granularmetric composition of M kind product;

2) calculate j-th stage particle size fraction material in i-th layer of pan feeding and account for the percentage ratio of total pan feedingCalculate i-th layer of pan feeding total amount and account for the percentage ratio of total pan feedingAnd the particle size fraction composition of each layer, wherein N is grain size category number, G in screening product_i,jIt is the percentage ratio that in i-th layer of product, j-th stage particle size fraction accounts for this layer of product;

3) calculate j-th stage particle size fraction material in i-th layer of pan feeding and account for the percentage ratio Y of this layer of pan feeding_i,j, the percentage ratio that namely in i-th layer of pan feeding, each particle size fraction material accounts for total pan feeding is respectively divided by each layer pan feeding total amount and accounts for the percentage ratio of total pan feeding, $Y_{i,j}=\frac{X_{i,j}}{X_i}=\frac{\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}}{\underset{j=1}{\overset{N}{\Σ}}\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}};$

4) calculate particle size fraction in i-th layer of pan feeding and account for the percentage ratio sum of this particle size fraction pan feeding less than the material of i-th layer of screen mesh sizeWherein p is the particle size fraction granularity progression less than screen mesh size;

5) calculate particle size fraction in i-th layer of siftage and account for this particle size fraction pan feeding percentage ratio sum less than the material of i-th layer of screen mesh sizeWherein p is the particle size fraction granularity progression less than screen mesh size;

6) calculate particle size fraction in i-th layer of oversize and account for this particle size fraction pan feeding percentage ratio sum less than the material of i-th layer of screen mesh sizeWherein p is the particle size fraction granularity progression less than screen mesh size;

7) according to step 4), 5), 6) in the α that draws_i、β_iAnd θ_i, i-th layer of sieved through sieve efficiency is calculated as follows:

${\mathrm{\η}}_i=\frac{({\mathrm{\α}}_i-{\mathrm{\θ}}_i)({\mathrm{\β}}_i-{\mathrm{\α}}_i)100}{{\mathrm{\α}}_i({\mathrm{\β}}_i-{\mathrm{\θ}}_i)(100-{\mathrm{\α}}_i)}\×100\%$

Thus obtaining asphalt mixing to vibrate the screening efficiency of each layer.

Described step 1) the middle productivity γ calculating M kind product_i(i=1,2 ..., M), comprise the following steps:

1.1) majorized function of screening product yield is set up:

Object function: $\underset{j=1}{\overset{N}{\Σ}}{(G_j-\underset{i=1}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{ij}/100)}^2=Min;$

Constraints: $\underset{i=1}{\overset{M}{\Σ}}{\mathrm{\γ}}_i=100;$

Wherein, N is grain size category number in screening product; M is screening product number; G_jThe percentage ratio of total pan feeding is accounted for for j-th stage particle size fraction in total pan feeding;G_i,jIt is the percentage ratio that in i-th layer of product, j-th stage particle size fraction accounts for this layer of product;

1.2) to step 1.1) in function adopt linear programming method to be optimized, thus the productivity γ of the M kind product obtained after drawing M-1 layer bolting_i。

Described step 1) in product serial number particle size fraction arrange from large to small, i=1 represents the 1st layer of product that particle size fraction is maximum, and i=M represents the M shell product that particle size fraction is minimum.

Described step 1) according to Vibration Screen hole dimension, select the square hole standard screen of same screen size, material carried out sieve test, it is thus achieved that the granularmetric composition of total pan feeding and M kind product, obtain j-th stage particle size fraction in total pan feeding and account for the percentage ratio G of total pan feeding_j; In i-th layer of product, j-th stage particle size fraction accounts for the percentage ratio G of this layer of product_i,j。

Described vibrosieve is multilayer linear vibration screen.

Compared with prior art, the present invention is directed to the multiple product of asphalt mixing Multilayer vibrating screen and the complex working condition of multiple particle size fraction, under the continuous large-tonnage condition of production of reality, the particle size fraction content of each screen layer oversize material, siftage material is obtained by testing sample, and calculate productivity thus obtaining screening efficiency, the present invention is when quantitative test, and no matter screen cloth level is how many, can calculate acquisition siftage raw meal particle size level content, the present invention calculates the screening process that can reflect vibrosieve really according to total efficiency formula, calculate respectively particle size fraction in each layer pan feeding be smaller in size than the material of this layer of screen mesh size account for pan feeding at the corresponding levels percentage ratio and, in each layer screen cloth siftage particle size fraction be smaller in size than the material of this layer of screen mesh size account for pan feeding at the corresponding levels percentage ratio and, and particle size fraction is smaller in size than the material of this layer of screen mesh size and accounts for the percentage ratio sum of pan feeding at the corresponding levels in each layer screen cloth oversize, take into full account the situation that the fine grained of saturating sieve is stayed in oversize, have also contemplated that the situation of the loss that coarse grain sieves thoroughly simultaneously, solve traditional asphalt mixing bolting efficiency calculations and produce the actual problem greatly differed from each other.

Accompanying drawing explanation

Fig. 1 is the asphalt mixing plant linear vibrating screen schematic diagram that the present invention uses.

Detailed description of the invention

Below in conjunction with embodiment, the present invention will be further described.

The computational methods of asphalt mixing multilayer linear vibration screen screening efficiency, comprise the following steps:

1) M-1 layer vibrosieve M kind product yield γ is calculated_i(i=1,2 ..., M), namely account for the percentage ratio of total pan feeding, and obtain total pan feeding and the granularmetric composition of M kind product. Product is the material before discharge from screening plant, further process or recirculation; Product yield is each product obtained after screening accounting in total pan feeding, and the screen cloth of the vibrosieve the superiors is defined as ground floor, and orlop screen cloth is defined as last layer.

1.1) majorized function of the problem of screening product yield is set up, namely

Object function: $\underset{j=1}{\overset{N}{\Σ}}{(G_j-\underset{i=1}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{ij}/100)}^2=Min---\left(1\right)$

Constraints: $\underset{i=1}{\overset{M}{\Σ}}{\mathrm{\γ}}_i=100---\left(2\right)$

In formula:

N sieves grain size category number in product;

M sieves product number;

G_jIn actual pan feeding, j-th stage particle size fraction accounts for the percentage ratio of total pan feeding;

G_i,jIn i-th layer of product, j-th stage particle size fraction accounts for the percentage ratio of this layer of product, and wherein product serial number particle size fraction arranges from large to small, and i=1 represents the 1st kind of product that particle size fraction is maximum, and i=M represents the M kind product that particle size fraction is minimum; γ_iThe productivity of i-th layer of product.

1.2) to 1.1) in function adopt linear programming method be optimized, draw the productivity γ of sorted product_i(i=1,2 ..., M).

2) calculate j-th stage particle size fraction material in i-th layer of pan feeding and account for the percentage ratio of total pan feeding, calculate i-th layer of pan feeding total amount and account for the percentage ratio of total pan feeding and the particle size fraction composition of each layer;

Making screen cloth layering rule keep consistent with product serial number, namely ground floor screen cloth oversize is the first product ..., M-1 layer screen cloth oversize M-1 kind product, M-1 layer screen cloth siftage is M kind product.

I-th layer of screen cloth pan feeding is the productivity sum of the productivity of i-th layer of oversize and i-th layer of siftage, and i-th layer of siftage is i+1 layer pan feeding. I-th layer of oversize productivity is multiplied by the percentage ratio of each grade in i-th layer of oversize and i-th layer of siftage productivity is multiplied by the percentage ratio summation of each grade in i-th layer of siftage.

In i-th layer of pan feeding (i.e. the i-th-1 layer siftage), j-th stage particle size fraction material accounts for the percentage ratio of total pan feeding and is formulated as:

$X_{i,j}=\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}---\left(3\right)$

Note 1: when formula (3) calculates, the meaning of i=M is M kind product, is M-1 layer siftage, and in formula calculated below, implication during i=M is identical.

I-th layer of pan feeding (the i-th-1 layer siftage) accounts for the percentage ratio X of total pan feeding_iIt is expressed as with formula:

$X_i=\underset{j=1}{\overset{N}{\Σ}}{X}_{i,j}=\underset{j=1}{\overset{N}{\Σ}}\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}---\left(4\right)$

3) calculate jth particle size fraction material in i-th layer of pan feeding (the i-th-1 layer siftage) and account for the percentage ratio Y of this layer of pan feeding_i,j:

$Y_{i,j}=\frac{X_{i,j}}{X_i}=\frac{\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}}{\underset{j=1}{\overset{N}{\Σ}}\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}}---\left(5\right)$

4) particle size fraction is calculated in i-th layer of pan feeding (the i-th-1 layer siftage) less than i-th layer of screen mesh size l_iMaterial account for the percentage ratio sum α of this particle size fraction pan feeding_i:

${\mathrm{\α}}_i=\underset{j=1}{\overset{p}{\Σ}}{Y}_{i,j}---\left(6\right)$

5) particle size fraction is calculated in i-th layer of siftage less than i-th layer of screen mesh size l_iMaterial account for this particle size fraction pan feeding percentage ratio sum β_i:

${\mathrm{\β}}_i=\underset{j=1}{\overset{p}{\Σ}}{Y}_{i-1,j}---\left(7\right)$

6) particle size fraction is calculated in i-th layer of oversize less than i-th layer of screen mesh size l_iMaterial account for this particle size fraction pan feeding percentage ratio sum θ_i:

${\mathrm{\θ}}_i=\underset{j=1}{\overset{p}{\Σ}}{G}_{i,j}---\left(8\right)$

Wherein, formula (6), (7), p means particle size fraction less than screen mesh size l in (8)_iGranularity progression;

7) according to step 4), 5), 6) in the α that draws_i、β_iAnd θ_i, i-th layer of sieved through sieve efficiency is calculated as follows:

${\mathrm{\η}}_i=\frac{({\mathrm{\α}}_i-{\mathrm{\θ}}_i)({\mathrm{\β}}_i-{\mathrm{\α}}_i)100}{{\mathrm{\α}}_i({\mathrm{\β}}_i-{\mathrm{\θ}}_i)(100-{\mathrm{\α}}_i)}\×100\%---\left(9\right)$

Wherein: η_iI-th layer of sieved through sieve efficiency;

α_iLess than i-th layer of screen mesh size l in i-th layer of pan feeding_iGranularity content;

β_iIn i-th layer of siftage, particle size fraction is less than i-th layer of screen mesh size l_iGranularity content;

θ_iIn i-th layer of oversize, particle size fraction is less than i-th layer of screen mesh size l_iGranularity content.

Referring to Fig. 1, the present invention is with four layers of linear vibrating screen screening efficiency computational methods of asphalt mixing plant for specific embodiment:

1) the 1st layer of oversize in 4 layers of vibrosieve, the 2nd layer of oversize, the 3rd layer of oversize, the 4th layer of oversize and 5 kinds of product yields in the 4th layer of sieve afternoon are calculated:

1.1) determine the partition size of Vibration Screen according to operating mode, in this example, the partition size of 4 layers of screen cloth is respectively as follows: λ₁=21.5mm, λ₂=15mm, λ₃=11mm, λ₄=3mm. Sampling box direct sample is used: pan feeding, the oversize of the 1st layer of compass screen surface, the 2nd layer of compass screen surface oversize, the oversize of the 3rd layer of compass screen surface, the oversize of the 4th layer of compass screen surface and siftage under each material bin. According to Vibration Screen hole dimension, select the square hole standard screen of same screen size, manually material is carried out sieve test, obtain the granularmetric composition of pan feeding, the oversize of the 1st layer of compass screen surface, the 2nd layer of compass screen surface oversize, the oversize of the 3rd layer of compass screen surface, the oversize of the 4th layer of compass screen surface and 5 kinds of product materials of siftage, referring to table 1.

Table 1 product granularity composition (%)

1.2) majorized function formed according to formula (1), (2) adopts linear programming method to be optimized, it is thus achieved that the productivity of 5 kinds of products. The productivity of the 1st layer of oversize is 7.16%; The productivity of second layer oversize is 20.85%; The productivity of third layer oversize is 14.67%; The productivity of the 4th layer of oversize is 22.96%, and the productivity of the 4th layer of siftage is 34.37%.

2) productivity of each particle size fraction material in the 4th layer of pan feeding (the 3rd layer of siftage) is calculated according to formula (3), (4): the 4th layer of oversize and the 4th layer of each particle size fraction of siftage account for ratio at the corresponding levels and be multiplied by the productivity addition of the 4th layer of oversize and the 4th layer of siftage respectively; Calculate the productivity of each particle size fraction material in the 3rd layer of pan feeding (the 2nd layer of siftage): the 3rd layer of oversize and the 3rd layer of each particle size fraction of siftage account for ratio at the corresponding levels and be multiplied by the productivity addition of the 3rd layer of oversize and the 3rd layer of siftage respectively; Calculate the productivity of each particle size fraction material in the 2nd layer of pan feeding (the 1st layer of siftage): the 2nd layer of oversize and the 2nd layer of each particle size fraction of siftage account for ratio at the corresponding levels and be multiplied by the productivity addition of the 2nd layer of oversize and the 2nd layer of siftage respectively; Calculate the productivity of each particle size fraction material in the 1st layer of pan feeding: the 1st layer of oversize and the 1st layer of each particle size fraction of siftage account for ratio at the corresponding levels and be multiplied by the productivity addition of the 1st layer of oversize and the 1st layer of siftage respectively. Result is referring to table 2:

2 each layers of screen cloth siftage of table account for percentage ratio and each particle size fraction composition of total pan feeding

3) calculate each particle size fraction material in each layer pan feeding according to formula (5) and account for the percentage ratio of this layer of pan feeding total amount: the percentage ratio that each particle size fraction material accounts for total pan feeding is respectively divided by each layer pan feeding total amount and accounts for the percentage ratio of total pan feeding, referring to table 3:

In 3 each layers of pan feeding of table, each particle size fraction material accounts for the percentage ratio of this layer of pan feeding total amount

4) calculate particle size fraction in each layer pan feeding respectively according to formula (6) to be smaller in size than the material of this layer of screen mesh size and account for the percentage ratio sum of pan feeding at the corresponding levels:

Fine particle content a in 1st layer of compass screen surface pan feeding₁=93.70%;

Fine particle content a in 2nd layer of compass screen surface pan feeding₂=79.94%;

Fine particle content a in 3rd layer of compass screen surface pan feeding₃=81.62%;

Fine particle content a in 4th layer of compass screen surface pan feeding₄=48.61%.

5) calculate particle size fraction in each layer screen cloth siftage respectively according to formula (7) to be smaller in size than the material of this layer of screen mesh size and account for the percentage ratio sum of pan feeding at the corresponding levels:

Fine particle content β in 1st layer of screen cloth siftage₁=97.53%;

Fine particle content β in 2nd layer of screen cloth siftage₂=98.75%;

Fine particle content β in 3rd layer of screen cloth siftage₃=98.16%;

Fine particle content β in 4th layer of screen cloth siftage₄=78.0%.

6) calculate particle size fraction in each layer screen cloth oversize respectively according to formula (8) to be smaller in size than the material of this layer of screen mesh size and account for the percentage ratio sum of pan feeding at the corresponding levels:

Fine particle content θ in 1st layer of screen cloth oversize₁=44.0%;

Fine particle content θ in 2nd layer of screen cloth oversize₂=15.0%;

Fine particle content θ in 3rd layer of screen cloth oversize₃=17.0%;

Fine particle content θ in 4th layer of screen cloth oversize₄=4.60%.

7) screening efficiency of each layer screen cloth of vibrosieve is calculated respectively according to formula (9).

1st layer of sieved through sieve efficiency is η_s1=60.24%;

2nd layer of sieved through sieve efficiency is η_s2=90.96%;

3rd layer of sieved through sieve efficiency is η_s3=87.78%;

4th layer of sieved through sieve efficiency is η_s4=70.55%;

Thus completing the calculating of Vibration Screen component efficiency.

The present invention is directed to the multiple product of asphalt mixing Multilayer vibrating screen and the complex working condition of multiple particle size fraction, under the continuous large-tonnage condition of production of reality, the particle size fraction content of each screen layer oversize material, siftage material is obtained by testing sample, and calculate productivity thus obtaining screening efficiency, the present invention is when quantitative test, no matter screen cloth level is how many, can calculate acquisition siftage raw meal particle size level content;The present invention calculates the screening process that can reflect vibrosieve really according to total efficiency formula, calculate respectively particle size fraction in each layer pan feeding be smaller in size than the material of this layer of screen mesh size account for pan feeding at the corresponding levels percentage ratio and, in each layer screen cloth siftage particle size fraction be smaller in size than the material of this layer of screen mesh size account for pan feeding at the corresponding levels percentage ratio and, and particle size fraction is smaller in size than the material of this layer of screen mesh size and accounts for the percentage ratio sum of pan feeding at the corresponding levels in each layer screen cloth oversize, take into full account the situation that the fine grained of saturating sieve is stayed in oversize, have also contemplated that the situation of the loss that coarse grain sieves thoroughly simultaneously, solve traditional asphalt mixing bolting efficiency calculations and produce the actual problem greatly differed from each other.

The computational methods of the present invention can realize programming automatic calculation on experimental data basis, and ratio traditional computational methods more operability, artificial amount of calculation is greatly reduced.

Claims (5)

1. the computational methods of an asphalt mixing vibrosieve efficiency, it is characterised in that: comprise the following steps:

1) the productivity γ of the M kind product obtained after calculating M-1 layer bolting_i(i=1,2 ..., M), namely account for the percentage ratio of total pan feeding, and obtain total pan feeding and the granularmetric composition of M kind product;

2) calculate j-th stage particle size fraction material in i-th layer of pan feeding and account for the percentage ratio of total pan feedingCalculate i-th layer of pan feeding total amount and account for the percentage ratio of total pan feedingAnd the particle size fraction composition of each layer, wherein N is grain size category number, G in screening product_i,jIt is the percentage ratio that in i-th layer of product, j-th stage particle size fraction accounts for this layer of product;

3) calculate j-th stage particle size fraction material in i-th layer of pan feeding and account for the percentage ratio Y of this layer of pan feeding_i,j, the percentage ratio that namely in i-th layer of pan feeding, each particle size fraction material accounts for total pan feeding is respectively divided by each layer pan feeding total amount and accounts for the percentage ratio of total pan feeding $Y_{i,j}=\frac{X_{i,j}}{X_i}=\frac{\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}}{\underset{j=1}{\overset{N}{\Σ}}\underset{i}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{i,j}};$

4) calculate particle size fraction in i-th layer of pan feeding and account for the percentage ratio sum of this particle size fraction pan feeding less than the material of i-th layer of screen mesh sizeWherein p is the particle size fraction granularity progression less than screen mesh size;

5) calculate particle size fraction in i-th layer of siftage and account for this particle size fraction pan feeding percentage ratio sum less than the material of i-th layer of screen mesh size ${\mathrm{\β}}_i=\underset{j=1}{\overset{p}{\Σ}}{Y}_{i-1,j};$

6) calculate particle size fraction in i-th layer of oversize and account for this particle size fraction pan feeding percentage ratio sum less than the material of i-th layer of screen mesh size ${\mathrm{\θ}}_i=\underset{j=1}{\overset{p}{\Σ}}{G}_{i,j};$

7) according to step 4), 5), 6) in the α that draws_i、β_iAnd θ_i, i-th layer of sieved through sieve efficiency is calculated as follows:

${\mathrm{\η}}_i=\frac{({\mathrm{\α}}_i-{\mathrm{\θ}}_i)({\mathrm{\β}}_i-{\mathrm{\α}}_i)100}{{\mathrm{\α}}_i({\mathrm{\β}}_i-{\mathrm{\θ}}_i)(100-{\mathrm{\α}}_i)}\×100\%$

Thus obtaining the screening efficiency of each layer of asphalt mixing vibrosieve.

2. the computational methods of asphalt mixing vibrosieve efficiency according to claim 1, it is characterised in that: described step 1) the middle productivity γ calculating M kind product_i(i=1,2 ..., M), comprise the following steps:

1.1) majorized function of screening product yield is set up:

Object function: $\underset{j=1}{\overset{N}{\Σ}}{(G_j-\underset{i=1}{\overset{M}{\Σ}}{\mathrm{\γ}}_i{G}_{ij}/100)}^2=Min;$

Constraints: $\underset{i=1}{\overset{M}{\Σ}}{\mathrm{\γ}}_i=100;$

Wherein, N is grain size category number in screening product; M is screening product number; G_jThe percentage ratio of total pan feeding is accounted for for j-th stage particle size fraction in total pan feeding; G_i,jIt is the percentage ratio that in i-th layer of product, j-th stage particle size fraction accounts for this layer of product;

1.2) to step 1.1) in function adopt linear programming method to be optimized, thus the productivity γ of the M kind product obtained after drawing M-1 layer bolting_i。

3. the computational methods of asphalt mixing vibrosieve efficiency according to claim 2, it is characterized in that: described step 1) in product serial number particle size fraction arrange from large to small, i=1 represents the 1st layer of product that particle size fraction is maximum, and i=M represents the M shell product that particle size fraction is minimum.

4. the computational methods of asphalt mixing vibrosieve efficiency according to claim 3, it is characterized in that: described step 1) according to Vibration Screen hole dimension, select the square hole standard screen of same screen size, material is carried out sieve test, obtain total pan feeding and the granularmetric composition of M kind product, obtain j-th stage particle size fraction in total pan feeding and account for the percentage ratio G of total pan feeding_j;In i-th layer of product, j-th stage particle size fraction accounts for the percentage ratio G of this layer of product_i,j。

5. the computational methods of asphalt mixing vibrosieve efficiency according to claim 1, it is characterised in that: described vibrosieve is multilayer linear vibration screen.