JPH04297908A - Concentration controller for wash solution - Google Patents

Abstract

PURPOSE:To simultaneously control the concentration and liquid level of a wash solution obtained by supplying a stock solution for washing and water. CONSTITUTION:The undiluted solution is supplied through an undiluted solution supply valve 8 to a vessel and water is supplied through a water supply valve 5 to the vessel. In this vessel, the concentration of the wash solution is detected by a concentration detector 3, and the liquid level is detected by a level detector 6. A concentration control part 4 calculates an undiluted solution supply amount FDA and a water supply amount FDW per unit time having a ratio so that deviation between a detected concentration value PV1 and a set concentration value SV1 of the wash solution can be close to zero. A level control part 7 calculates a total supply amount FL per unit time adding the amounts of the undiluted solution and water so that deviation between a detected level value PV2 and a set level value SV2 of the level can be close to zero. An undiluted solution/water mixing amount calculation part 11 calculates mixing amounts FA and FW of the total supply amount FL so as to maintain the concentration of the wash solution at the set concentration value SV1 based on the undiluted solution supply amount FDA, water supply amount FDW, total supply amount FL and set concentration value SV1 and according to these mixing amounts, the undiluted solution supply valve 8 and the water supply valve 5 are controlled.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention controls the opening degrees of a stock solution supply valve that supplies a stock solution for cleaning and a water supply valve that supplies water to control the concentration and liquid level of a cleaning solution in a container. The present invention relates to a device for controlling the concentration of a cleaning solution.

0002

2. Description of the Related Art There is a pickling equipment for cleaning metal plates, which simultaneously cleans the front and back surfaces of a metal plate by immersing the metal plate in a pickling solution stored in a container. When plates are continuously passed through this pickling equipment, the concentration and liquid level of the pickling solution naturally change. Therefore, a concentration control device is provided to control the concentration and liquid level of the pickling solution in the container by controlling the opening degrees of the stock solution supply valve that supplies the stock solution and the water supply valve that supplies water.

FIG. 2 is a schematic diagram of a conventional concentration control device of this type. In the figure, a metal plate 1 is immersed in a pickling solution 2 stored in a container and passed through it continuously. In this case, the stock solution is supplied into the container through the stock solution supply valve 8, and the water is supplied into the container through the water supply valve 5. Among these, the flow rate of the stock solution per unit time (hereinafter simply referred to as flow rate) is detected by the flow rate detector 22, and the detected flow rate value PV3 is applied to the flow rate adjustment section 23. The flow rate adjustment unit 23 uses this flow rate detection value PV3 and the flow rate set value SV3.
A manipulated variable is calculated such that the deviation from the undiluted solution supply valve 8 becomes zero, and the opening degree of the stock solution supply valve 8 is controlled by an adjustment signal corresponding to this manipulated variable. Therefore, a constant amount of stock solution is always supplied.

On the other hand, the concentration of the pickling solution 2 is detected by a concentration detector 3, and a detected concentration value PV1 is applied to a concentration adjusting section 4. In the concentration adjustment section 4, the concentration detection value PV1
The operation amount of the water supply valve 5 that brings the deviation between the concentration setting value SV1 and the concentration setting value SV1 closer to zero is calculated, and an adjustment signal corresponding to this operation amount is given to the signal selection section 21. Further, the level of the pickling solution 2 is detected by a level detector 6, and a detected level value PV2 is applied to a level adjusting section 7. The level adjustment section 7 compares the level detection value PV2 and the level set value SV2, calculates the amount of operation of the water supply valve 5 that brings the deviation closer to zero, and sends an adjustment signal corresponding to this amount of operation to the signal selection section. Give to 21. Therefore, the signal selection section 21 compares the magnitudes of the adjustment signals from the concentration adjustment section 4 and the level adjustment section 7, and controls the opening degree of the water supply valve 5 according to the larger adjustment signal.

[0005]

[Problem to be Solved by the Invention] The rate of decrease in concentration and level of the pickling solution 2 in the container varies depending on the amount of plate passing (the area of plate passing per unit time), the temperature of the pickling solution, the ambient temperature, etc. Change. However, the conventional concentration control device shown in Fig. 2 does not take into account changes in the concentration or the rate of decrease in level, and does not take into account changes in the rate of decrease in concentration or level. The flow rate was set.

For this reason, when the rate of decrease in the concentration or level of the pickling solution 2 is small, the amount of the stock solution supplied becomes excessive, and since a large amount of water is supplied to adjust the concentration, there is a surplus in the pickling solution 2. This excess solution was discarded outside the container. Furthermore, when the rate of decrease in the concentration or level of the pickling solution 2 is extremely large, the accuracy of concentration control is sacrificed in order to ensure that the plate 1 is immersed in the pickling solution 2 to maintain the level.

However, when the rate of decrease in the concentration or level of the pickling solution 2 is small, the pickling solution is wasted and the product cost increases; When the ratio is extremely large, there is a problem in that the accuracy of controlling the concentration decreases and the quality of the products deteriorates.

The present invention was made to solve the above problems, and even if the cleaning conditions change, the concentration and level of the pickling solution can be maintained within a predetermined range without creating a surplus in the cleaning solution. An object of the present invention is to obtain a device for controlling the concentration of a cleaning solution that can maintain the concentration of the cleaning solution.

[0009]

[Means for Solving the Problems] The present invention controls the opening degrees of a stock solution supply valve that supplies a stock solution for cleaning and a water supply valve that supplies water to control the concentration and liquid level of a cleaning solution in a container. In a cleaning solution concentration control device that controls the level, the concentration is calculated to calculate the raw solution supply amount and water supply amount per unit time having a ratio that brings the deviation between the detected concentration value and the concentration setting value of the cleaning solution close to zero. an adjusting means, a level adjusting means for calculating the total supply amount of the undiluted solution and water per unit time so that the deviation between the detected level value of the liquid level of the cleaning solution and the level setting value approaches zero; an allocation amount for calculating an allocation amount between the stock solution and water of the total supply amount to maintain the concentration of the cleaning solution at the concentration setting value based on the supply amount of the stock solution, the water supply amount, the total supply amount, and the concentration setting value; and a calculation means, and controls the stock solution supply valve and the water supply valve according to the distribution amount.

0010

[Operation] In this invention, the amount of raw solution supplied and the amount of water supplied per unit time are calculated at a ratio that maintains the change in the concentration of the cleaning solution, while at the same time maintaining the change in the level of the cleaning solution. Calculate the total supply amount of the undiluted solution and water per unit time, and calculate the distribution amount of the undiluted solution and water for the total supply amount to maintain the concentration of the cleaning solution at the set value based on these calculation results and the concentration setting value. Since it is calculated, simultaneous control of concentration and level is possible.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram of an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 1 indicate the same elements. Here, water is supplied to the container through the water supply valve 5, and stock solution is supplied to the container through the stock solution supply valve 8. Further, the concentration of the pickling solution 2 in the container is detected by a concentration detector 3, and a detected concentration value PV1 is added to the concentration adjusting section 4, and the level of the pickling solution 2 is detected by a level detector 6, and a detected level value PV2 is added to the concentration adjusting section 4. is added to the level adjustment section 7. In this case, the concentration adjustment unit 4 compares the detected concentration value PV1 and the concentration set value SV1, and adjusts the raw solution supply amount FDA and water supply amount FDW to have a ratio that brings the difference close to zero.
is calculated and added to the stock solution/water distribution amount calculation section 11. Also,
The level adjustment section 7 calculates the total supply amount FL of the stock solution and water so that the deviation between the level detection value PV2 and the level setting value SV2 approaches zero, and also adds it to the stock solution/water distribution calculation section 11. The stock solution/water distribution amount calculation unit 11 calculates the stock solution distribution amount FA and the water distribution amount FW according to a predetermined relational expression based on the raw solution supply amount FDA, the water supply amount FDW, the total supply amount FL and the detected concentration value PV1. , and is configured to apply adjustment signals corresponding to these distribution amounts to the water supply valve 5 and the stock solution supply valve 8.

The operation of this embodiment configured as described above will be explained below.

First, the density adjustment section 4 adjusts the detected density value PV1.
and the concentration setting value SV1, and determine the stock solution supply amount FDA and the water supply amount F, which have a ratio that brings the difference close to zero.
Calculate DW. In this case, if the concentration of pickling solution 2 becomes lower, the raw solution supply amount FDA increases and the water supply amount FD
A value that decreases W is calculated. In addition, the level adjustment section 7
is the total supply amount F of stock solution and water to bring the deviation between level detection value PV2 and level set value SV2 close to zero.
Calculate L.

Next, the stock solution/water distribution amount calculation section 11 executes the following calculation based on the calculated stock solution supply amount FDA, water supply amount FDW, total supply amount FL and concentration setting value PV1. FA = (FL - FDA - FDW) x SV1 /10
0 ÷ β/100 + FDA = (FL −
FDA-FDW)×SV1/β+FDA
...(1) FW = FL -FA
=FL-(FL-FDA-FDW)×
SV1/β-FDA = (FL-FDA
-FDW)・(1-SV1/β)+FDW
...(2) where β is the acid concentration [%] of the stock solution.

The distribution amount F of the stock solution calculated in this way
A and the water distribution amount FW are nothing but what maintains the concentration of the pickling solution at the concentration setting value PV1, and the water supply valve 5 and the stock solution supply valve 8 are controlled according to these distribution amounts.

Thus, according to this embodiment, the stock solution supply amount F is corrected according to the change in the detected concentration value PV1.
While calculating DA and water supply amount FDW, total supply amount FL is corrected according to changes in level detection value PV2.
Further, from these calculation results, the distribution amount FA of the stock solution to maintain the concentration of the pickling solution 2 at the concentration setting value PV1 is calculated.
Since we are calculating the distribution amount of water FW, the pickling solution 2
The concentration and level of can be controlled simultaneously.

[0017] In the above embodiments, the most frequently used pickling solution was explained, but the present invention is not limited thereto, and most cleaning solutions that supply the undiluted solution and water for cleaning can be used. Needless to say, it can be applied to

[0018]

Effects of the Invention As is clear from the above explanation, according to the present invention, even if the rate of decrease in concentration or level changes due to changes in cleaning conditions, the pickling solution can be improved without creating a surplus in the cleaning solution. The concentration and level can be maintained within a predetermined range, thereby preventing an increase in product costs due to wasted cleaning solution and a decrease in product quality due to a decrease in concentration control accuracy.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a schematic diagram of a conventional cleaning solution concentration control device.

[Explanation of symbols]

2 Pickling solution 3 Concentration detector 4 Density adjustment section 5 Water supply valve 6 Level detector 7 Level adjustment section 8 Stock solution supply valve 11 Stock solution/water distribution amount calculation section

Claims (1)

[Claims] [Claim 1] A cleaning solution concentration that controls the concentration and liquid level of the cleaning solution in a container by controlling the opening degrees of a stock solution supply valve that supplies a stock solution for cleaning and a water supply valve that supplies water. In the control device, a concentration adjusting means for calculating an amount of raw solution supplied and an amount of water supplied per unit time having a ratio such that a deviation between a detected concentration value and a set concentration value of the cleaning solution approaches zero; Level adjustment means for calculating the total supply amount of the raw solution and water per unit time so that the deviation between the detected level value of the liquid level and the level set value approaches zero, and the calculated raw solution supply amount and water supply. a distribution amount calculation means for calculating an amount to be distributed between the undiluted solution and water in the total supply amount to maintain the concentration of the cleaning solution at the concentration setting value based on the total supply amount and the concentration setting value; A cleaning solution concentration control device characterized by controlling the stock solution supply valve and the water supply valve according to the amount.