JP2723945B2 - Solution quantitative preparation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for quantitatively preparing a solution.

<Conventional technology> For example, when a slurry or suspension solution is blended at a fixed ratio for a plurality of brands, usually, the solution is cut out individually into tanks using a metering pump such as a plunger pump or a diaphragm pump and blended. A method is used.

As an example, as shown in FIG. 3, from the five tanks 11 to 15 storing the solutions A, B, C, D and E having different specific gravities and viscosities, the respective cutoff valves 21 to 25 are sequentially opened. Meanwhile, the metering pump 1, such as a plunger pump, connected to the pipes 31 to 35, for example, is operated to cut out the required amount into the mixing tank 2 and rotate the stirrer 3 to mix and mix.

At this time, the order of cutting out each solution from each of the tanks 11 to 15 is performed by a cutting program set in advance in the mixing control device 4, and selection of a brand and setting of the cutout amount are performed by the operator each time. It is performed manually via the control device 4.

Now, cut amount per stroke using a metering pump 1 is V ₀ (l), for example, a solution from the tank 11, 13, 15 A, C, 3 issues a V _A of E (l), V _C ( l) and V _E (l) are cut out and blended by the following procedure.

First, after opening the cut valve 21 performs extraction of the solution A to start the metering pump 1, valve cut to stop the metering pump 1 at the timing when the number of strokes has reached V _A / V ₀ of the metering pump 1 Close 21. This means that the solution A has been cut out by V _A (l).

Next, after opening the cut-out valve 23, the metering pump 1 is started to cut out the solution C, and the number of strokes is reduced.
When V _C / V ₀ is reached, the metering pump 1 is stopped, the cutout valve 23 is closed, and the solution C is cut out by V _C (l).

Next, open the cut-out valve 25, and then
Is started to cut out the solution E, and at the timing when the stroke number of the metering pump 1 reaches V _E / V ₀ , the metering pump 1 is stopped, the cut-out valve 25 is closed, and the solution E is transferred to V _E (l).
Just cut out.

Then, the stirrer 3 attached to the mixing tank 2
Is operated to stir the solution in the preparation tank 2 for a certain period of time to prepare a preparation liquid.

<Problems to be Solved by the Invention> However, in the conventional dispensing equipment as described above, since the dispensing accuracy of the solution depends only on the cut-out amount per stroke of the dispensing pump 1, the dispensing pump 1 may change over time such as wear. Therefore, if the cutout amount per stroke changes, the compounding accuracy cannot be maintained.

The dispensing accuracy also depends on the case where the composition or specific gravity of the solution to be cut out changes due to mixing of the solution remaining in the pipes 31 to 35 or a change in the properties of the solution itself.

Therefore, it is necessary for the operator to measure the specific gravity and the like of the preparation liquid to check the preparation accuracy every time the preparation is performed, which poses a problem in labor saving.

An object of the present invention is to provide a method for quantitatively preparing a solution, which has been made to solve the above problems.

<Means for Solving the Problems> In the present invention, when two or more kinds of solutions having different specific gravities and viscosities are collectively cut out and mixed by one metering pump through a pipe, a predetermined cut-out volume is used. Calculating each set weight value; measuring the weight of the solution cut out from the metering pump; comparing each of the measured weight and the set weight value; and setting the measured weight value to the set weight value. A step of dispensing the cut out solution to the preparation tank in the next process when it is within a tolerance set in advance around the center, and temporarily stopping the dispensing when the solution is out of the tolerance, and a next step based on the result of this comparison. Correcting each cut-out volume.

<Action> According to the present invention, the weight of the solution cut out from the metering pump is measured and compared with a set weight value converted from a predetermined solution cut-out volume to correct the next cut-out volume. As a result, it is possible to prevent the effects of the change over time of the metering pump, the mixing of the residual solution in the pipe, or the change in the properties of the solution itself, and the compounding can be performed with high accuracy.

<Example> Hereinafter, an example of the method of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram schematically showing one embodiment of a blending facility according to the method of the present invention. In the figure, the same members as those of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

As shown in the figure, the mixing equipment of the present invention is provided with a measuring tank 5 equipped with a weight detector 6 such as a load cell on the output side of the metering pump 1. A cut-out valve 7 is attached to the bottom of the weighing tank 5, and a weight signal from the weight detector 6 is transmitted via a weight measuring device 8 to a mixing control device 4.
Is input to

Next, steps in the case where three brands of, for example, solutions A, C, and E are blended using the blending equipment of the present invention thus configured will be described.

First, the operator sends the metering pump 4
And per stroke of the cut volume V ₀ (l), the solution A, C, stocks and their E specific gravity _{ρ 1 (kg / l),} ρ 3
(Kg / l), ρ ₅ (kg / l), and cut-out capacity V
₁ (l), V ₃ (l), V ₅ (l) are manually input and a start command is given.

Therefore, the compounding control unit 4, sets the weight value W _1S (k when each solution A, C, E are cut by V _1, V _3, V ₅ respectively
g), W _3S (kg), and W _5S (kg) are calculated by the following formulas.

W _1S = ρ ₁ · V ₁ (1) W _3S = ρ ₃ · V ₃ (2) W _5S = ρ ₅ · V ₅ (3) The mixing control device 4 opened the cut-out valve 21. after performs clipping of the solution a to start the metering pump 1, counts the number of strokes metering pump 1, the number of counts N _1,
(4) below the application to learning coefficient k _n the N ₁ values in excised stop metering pump 1 at the timing when reaching valve 21, which is determined as 1.00 to closing time in the equation.

_{N 1 = (V 1 / V} 0) × (1 / k n) ...... (4) In this case, measuring the weight W ₁ (kg) of cut solution A into the measuring tank 5 by weight detector 6 Then, it is input to the compounding control device 4 via the weight measuring device 8, and the allowable upper limit value W _1U and the allowable lower limit value W _1L are calculated by the following equations (5) and (6).

W _1U = W _1S (1 + α) (5) W _1L = W _1S (1-α) (6) where α; a constant (where 0 <α ≦ 0.05) and
The upper limit value W _1U and the lower limit value W _1L are compared with the measured weight value W _{1 according} to the following equation. If the following equation (7) is satisfied, the cut-out capacity V ₁ is determined to be acceptable, and The cutout valve 6 is opened and the solution A is transferred to the preparation tank 2.

W _1L ≦ W ₁ ≦ W _1U (7) If the above formula is not satisfied, the preparation control device 4 determines that the cutout is abnormal, outputs an alarm to the operator, and outputs the next solution C And temporarily waits until the operator's action ends.

Next, the measured weight values W _1, the current learning coefficient actual value k of clipping volume V ₁ of the 1 stroke per metering pump 1 is calculated using the following equation (8).

k = W ₁ / W _1S = W ₁ / (ρ ₁ · V ₁ ) (8) Using the learning coefficient actual value k, a learning coefficient kn _{+ 1} to be applied next time is determined by the following equation (9). I do.

k _{n + 1} = k _n + β (k−k _n ) (9) where β: constant (however, 0 ≦ β ≦ 1).
After opening 23, the metering pump 1 is started to cut out the solution C, and calculations and determinations are performed using the equations (2) and (4) to (9) in the same manner as in the above steps (1) to (4).

Next, open the cut-out valve 25, and then
Is started to cut out the solution E, and the above steps ~
Calculation and determination are performed using the equations (3) to (9) in the same manner as in the above.

At the timing when the cutting-out of the solutions of all brands is completed, the preparation control device 4 operates the stirrer 3 to stir the solution in the preparation tank 2 for a certain period of time to complete the preparation of the preparation liquid.

The steps described above are summarized in FIG. In this figure, i = 1 to 5 corresponding to tanks 11 to 15 and i = 5
This shows a procedure of cutting out the solution from i to 5 in order from 1 and leading to stirring and mixing.

Although the above-described embodiment describes the preparation of five brand solutions, it goes without saying that the present invention is not limited to this, and can be applied regardless of the number of brands.

<Effects of the Invention> As described above, the present invention has the following advantages as compared with the conventional method.

(1) Each time a solution is cut out, its weight is measured, and it is confirmed that the measured weight value is equal to the set weight value. Then, mixing is performed, so that occurrence of abnormal mixing can be prevented beforehand. At the same time, labor saving can be achieved because no operator's check is required.

(2) Further, since the ratio between the set weight value of the solution and the cut-out measured weight value is learned and the temporal change of the metering pump is automatically corrected, the solution can always be accurately prepared.

[Brief description of the drawings]

FIG. 1 is a schematic diagram schematically showing an embodiment of the blending equipment according to the method of the present invention, FIG. 2 is a flowchart showing the procedure of the present invention, and FIG. 3 is an explanatory diagram showing a conventional example. . 1 ... Measuring pump, 2 ... Mixing tank, 3 ... Stirrer, 4 ...
Mixing control device, 5… Measuring tank, 6… Weight detector, 7 ……
Cut-out valve, 8… Weight measuring device, 11 ～ 15 …… Tank, 21 ～
25 ... cut-off valve, 31-35 ... piping, A, B, C, D, E ... solution.

Claims (1)

(57) [Claims] 1. When two or more solutions having different specific gravities and viscosities are collectively cut out and mixed by a single metering pump via a pipe, each set weight value is calculated from each cut-out volume set in advance. A step of measuring the weight of the solution cut out from the metering pump; a step of comparing the measured weight value with the set weight value; and the measured weight value is set in advance around the set weight value. If the amount is within the allowable range, the extracted solution is discharged to the blending tank for the next process, and if the value is out of the allowable range, the dispensing is temporarily stopped.Based on the result of the comparison, the next extraction volume is corrected. A method for quantitatively preparing a solution.