CN101590994A - Method for controlling liquid quantitative filling - Google Patents

Abstract

The present invention relates to liquid quantitative filling control technology field, particularly a kind of non-constant method for controlling liquid quantitative filling of flow velocity that can be used for can be guaranteed the accuracy rate of the liquid quantitative filling that flow velocity is non-constant dynamically according to current flow velocity automatic compensation lead; Method for controlling liquid quantitative filling of the present invention comprises the steps: 1) the startup can; 2) interior mean flow rate v of time period behind the calculating valve wide open; 3) calculate from starting the trickle weight Q that valve closes to the complete down periods of valve according to mean flow rate v ₁Can amount Q when 4) calculating should start valve closing ₀5) judge whether current can amount reaches Q ₀, in this way, then execution in step 6); 6) start valve closing.

Description

Method for controlling liquid quantitative filling

Technical field

The present invention relates to liquid quantitative filling control technology field, particularly a kind of non-constant method for controlling liquid quantitative filling of flow velocity that can be used for.

Background technology

The accuracy control of liquid quantitative filling is extensively to need in the production process of industrial products, medical product, daily living article product.In the mode that fills by gravity by the power of pump, can not ignore to the latter greatly with respect to being irritated container when the liquid source container, in pouring process, liquid level decline is extremely slow, and the flow velocity of liquid is constant in the time of then can thinking can.The quantitative control of this class can reach enough accurate effect with existing different control methods.The volume difference of irritating container when liquid source container and quilt reaches aforementioned degree far away, and comparatively obvious by the liquid level High variation in the liquid source container in the part pouring process, then the can flow velocity must correspondingly change, and it is non-constant that this kind situation promptly is called flow velocity.

At present, the non-constant quantitative filling of flow velocity adopts the mode of weighing to control, and its accuracy rate is generally on the low side.For example, during than the centrifugal casting of small dimension cylinder sleeve of engine blank, wish that iron water amount approaches the aequum of a workpiece as far as possible, but in the actual process process, limit by existing weight control method, iron water amount often deviation is bigger.Iron water amount is on the low side, and then blank is a waste product, and 1. on the high side then the causing of iron water amount waste molten iron; 2. waste energy; 3. the blank stock left for machining is excessive.Obviously, needing new control method makes the can amount enough accurate.

Existing liquid quantitative filling adopts the mode of weighing to carry out usually, existing liquid quantitative filling system comprises the liquid source container, irritated container and control setup, described liquid source container is by the solenoid control valve opening and closing, also being provided with the gravity sensing device is gathered irritating container, weight sensor all is connected with control setup with electromagnetic valve, by an amount of lead is set, the a certain setting value that the liquid weight of promptly ought packing into reaches before the aequum is promptly sent the shut the gate action, the expectation influx of blocking during the filling exit of closing the door equals lead just, to reach the accuracy control purpose of can amount.This control method lacks adaptive ability, still can guarantee sufficient accuracy in the occasion of constant flow rate, if flow velocity is non-constant, then can not control accurately.

Summary of the invention

In view of this,, the invention provides a kind of method for controlling liquid quantitative filling, can guarantee the accuracy rate of the liquid quantitative filling that flow velocity is non-constant dynamically according to current flow velocity automatic compensation lead in order to address the above problem.

The object of the present invention is achieved like this: method for controlling liquid quantitative filling comprises the steps:

1) starts can;

2) interior mean flow rate v of time period behind the calculating valve wide open;

3) calculate from starting the trickle weight Q that valve closes to the complete down periods of valve according to mean flow rate v ₁

Can amount Q when 4) calculating should start valve closing ₀

5) judge whether current can amount reaches Q ₀, in this way, then execution in step 6);

6) start valve closing.

Further, described step 2) specifically comprise the steps:

21) start can after, judge whether standard-sized sheet of can valve, as if standard-sized sheet, then execution in step 22)

22) gather the current weight M that is irritated container ₁, and start timing;

23) judge whether can reaches x%Q, wherein Q is required can amount, and the value of x makes the remaining filling time be enough to carry out remaining controlled step;

24) gather the current weight M that is irritated container ₂And time T;

25) the mean flow rate v=(M behind the calculating valve wide open ₂-M ₁)/T;

Further, in the step 3), calculate Q according to following formula ₁:

$Q_1=\frac{1}{2}v\×L;$

In the formula, L is the required time of valve-off;

Further, calculate according to following formula in the step 4):

$Q_0=Q-Q_1-\frac{1}{2}\mathrm{\&Delta;Q}-{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2;$

In the formula, Δ Q is the departure of last can; Q ₂Be constant, the product that its value equals exit area, exports and begins to close the door and irritated distance between vessel level constantly, irritated the liquid specific gravity three; Also comprise step 7) after the step 6), write down the departure of this can.

Method for controlling liquid quantitative filling of the present invention according to current flow velocity, carries out the self adaptation adjustment to lead, can guarantee the accuracy rate of the liquid quantitative filling that flow velocity is non-constant, saves can raw material and subsequent handling, improves yields.

Other advantages of the present invention, target, to set forth in the following description to a certain extent with feature, and to a certain extent,, perhaps can obtain instruction from the practice of the present invention based on being conspicuous to those skilled in the art to investigating hereinafter.Target of the present invention and other advantages can be passed through following specification sheets, claims, and the specifically noted structure realizes and obtains in the accompanying drawing.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with accompanying drawing:

Fig. 1 shows the schematic flow sheet of method for controlling liquid quantitative filling;

Fig. 2 is a liquid source container round exit valve closing process scheme drawing.

The specific embodiment

Hereinafter with reference to accompanying drawing, the preferred embodiments of the present invention are described in detail.

Referring to Fig. 1, the method for controlling liquid quantitative filling of present embodiment comprises the steps:

1) starts can;

2) interior mean flow rate v of time period behind the calculating valve wide open specifically comprises the steps:

21) start can after, judge whether standard-sized sheet of can valve, as if standard-sized sheet, then execution in step 22)

22) gather the current weight M that is irritated container ₁, and start timing;

23) judge whether can reaches x%Q, wherein Q is required can amount, the span of x is 1-100, the x value is big more, and final quantitative filling is accurate more, but the value of x must make the remaining filling time be enough to carry out remaining calculating, controlled step, usually be advisable with 70-80, as, when can reach required can amount 70% the time, carry out following steps;

24) gather the current weight M that is irritated container ₂And time T;

25) the mean flow rate v=(M behind the calculating valve wide open ₂-M ₁)/T;

3) calculate from starting the trickle weight Q that valve closes to the complete down periods of valve by following formula ₁:

$Q_1=\frac{1}{2}v\&times;L;$

In the formula, L is the required time of valve-off;

Can amount Q when 4) calculating should start valve closing ₀:

$Q_0=Q-Q_1-\frac{1}{2}\mathrm{\&Delta;Q}-{\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2;$

In the formula, Δ Q is the departure of last can, during can for the first time, and can be default according to historical data; Q ₂Be constant, the product that its value equals exit area, exports and begins to close the door and irritated distance between vessel level constantly, is irritated the liquid specific gravity three, its physical significance is to begin to close the door to be suspended from liquid between outlet and quilt filling vessel level constantly;

5) judge whether current can amount reaches Q ₀, in this way, then execution in step 6);

6) start valve closing;

7) write down the departure of this can.

About $Q_1=\frac{1}{2}v\&times;L$ Theory push away card

Referring to Fig. 2, wherein dash area is represented the valve shield portions.As seen from the figure, valve is by opening to the process of closing fully fully, puts u exactly and moves to the process of R by-R.Getting unit of length is m, and thinks that valve at the uniform velocity closes.

In the valve closing process, the area of liquid source container outlet changes with the variation of a u, can be determined by following formula:

$A\left(u\right)=2{\&Integral;}_u^R\sqrt{R^2-x^2}\mathrm{dx}$

$=x\sqrt{R^2-x^2}+R^2\arcsin \frac{x}{R}{|}_U^R$

$=\frac{\mathrm{\&pi;r}}{2}{R}^2-u\sqrt{R^2-u^2}-{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">R</figure-callout>}}^2\sin \frac{u}{R}(-R\&le;u\&le;R)$

If shape exit, garden is L from the beginning closing valve to closing outlet fully the used time, promptly when 0≤t≤L ,-R≤u≤R, replace:

$t=\frac{L}{2R}(u+R)$ Or $u=\frac{2R}{L}t-R$

Then liquid source container exit area with the rule that lockup t changes is:

$A\left(t\right)=\frac{\mathrm{\&pi;}}{2}{R}^2-R^2(\frac{2}{L}t-1)\sqrt{1-{(\frac{2}{L}t-1)}^2}-{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">R</figure-callout>}}^2\sin (\frac{2}{L}t-1)$

If the container exit flow rate of liquid is v=am/s

Flow infinitesimal on time interval [t, t+dt]:

$\mathrm{dQ}=\mathrm{aA}\left(t\right)\mathrm{dt}=a[\frac{\mathrm{\&pi;}}{2}{R}^2-R^2(\frac{2}{L}t-1)\sqrt{1-{(\frac{2}{L}t-1)}^2}-{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">R</figure-callout>}}^2\sin (\frac{2}{L}t-1)]\mathrm{dt}$

From starting the flow that closing valve is passed through to the time course [0, L] of complete closing containers outlet:

$Q_1=a{\&Integral;}_0^L[\frac{\mathrm{\&pi;}}{2}{R}^2-R^2(\frac{2}{L}t-1)\sqrt{1-{(\frac{2}{L}t-1)}^2}-{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">R</figure-callout>}}^2\sin (\frac{2}{L}t-1)]\mathrm{dt}$

$=a{[\frac{\mathrm{\&pi;}}{2}{R}^{2}t+\frac{R^2\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">L</figure-callout>}}{2}\cos (\frac{2}{L}t-1)]}_0^L-{\mathrm{<figure-callout\; id="2"\; label="aR"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">aR</figure-callout>}}^2\underset{0}{\overset{L}{\&Integral;}}(\frac{2}{L}t-1)\sqrt{1-{(\frac{2}{L}t-1)}^2}\mathrm{dt}$

$=\frac{1}{2}\mathrm{a\&pi;}{R}^{2}L\left(m^3\right)$

Integration in the following formula is through substitution of variable $z=\frac{2}{L}t-1,$ Can get:

$a{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">R</figure-callout>}}^2\&Integral;(\frac{2}{L}t-1)\sqrt{1-{(\frac{2}{L}t-1)}^2}\mathrm{dt}=\frac{L}{2}a{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">R</figure-callout>}}^2\underset{-1}{\overset{1}{\&Integral;}}z\sqrt{1-{\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">z</figure-callout>}}^2}\mathrm{dz}=0$ (integration of odd function on symmetric interval)

If be not activated closing valve, promptly under the state of container outlet standard-sized sheet, the flow that will pass through in [0, the L] time period is:

${\mathrm{<figure-callout\; id="2"\; label="Q"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">Q</figure-callout>}}_2=a\underset{0}{\overset{L}{\&Integral;}}\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="A2009101041730010H1.png"\; state="\{\{state\}\}">R</figure-callout>}}^2\mathrm{dt}=\mathrm{a\&pi;}{R}^{2}L\left(m^3\right)$

Can get: Q ₂=2Q ₁.

Promptly pushing away card shows: at the uniform velocity close in the closed procedure flow by container outlet, half of the flow that is passed through during just for the container outlet standard-sized sheet at valve in the identical time.This conclusion has proved $Q_1=\frac{1}{2}v\&times;L$ Be correct.

The above is the preferred embodiments of the present invention only, is not limited to the present invention, and obviously, those skilled in the art can carry out various changes and modification and not break away from technological thought of the present invention and scheme scope the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (4)

1. method for controlling liquid quantitative filling is characterized in that: comprise the steps:

1) starts can;

2) interior mean flow rate v of time period behind the calculating valve wide open;

3) calculate from starting the trickle weight Q that valve closes to the complete down periods of valve according to mean flow rate v ₁

Can amount Q when 4) calculating should start valve closing ₀

5) judge whether current can amount reaches Q ₀, in this way, then execution in step 6);

6) start valve closing.

2. method for controlling liquid quantitative filling as claimed in claim 1 is characterized in that: described step 2) specifically comprise the steps:

21) start can after, judge whether standard-sized sheet of can valve, as if standard-sized sheet, then execution in step 22)

22) gather the current weight M that is irritated container ₁, and start timing;

23) judge whether can reaches x%Q, wherein Q is required can amount, and the value of x makes the remaining filling time be enough to carry out remaining controlled step;

24) gather the current weight M that is irritated container ₂And time T;

25) the mean flow rate v=(M behind the calculating valve wide open ₂-M ₁)/T.

3. method for controlling liquid quantitative filling as claimed in claim 2 is characterized in that: in the step 3), calculate Q according to following formula ₁:

$Q_1=\frac{1}{2}v\&times;L;$

In the formula, L is the required time of valve-off.

4. method for controlling liquid quantitative filling as claimed in claim 3 is characterized in that: calculate according to following formula in the step 4):

$Q_0=Q-Q_1-\frac{1}{2}\mathrm{\&Delta;Q}-Q_2;$

In the formula, Δ Q is the departure of last can; Q ₂Be constant, the product that its value equals exit area, exports and begins to close the door and irritated distance between vessel level constantly, irritated the liquid specific gravity three; Also comprise step 7) after the step 6), write down the departure of this can.

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