JP2009213988A - System and method for controlling concentration of coating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating material concentration control system and method which can carry out concentration control of a coating material while controlling the level and the temperature in tanks. <P>SOLUTION: A mixing tank mixes a raw solution and a diluting solution, and stores the resulting solution and discharges out of or feeds the solution to the next stage, and a supply tank mixes the solution from the mixing tank and the diluting solution, and stores the resulting solution, and feed the solution to a storage line or feed back the solution to the mixing tank. The sugar concentration, level, and temperature are measured individually and the supply, discharge, and feed-back are adjusted based on these measured values. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a paint concentration control system and method for controlling the paint concentration by measuring the sugar content when the paint is diluted.

  There is a method of changing the coating amount with a constant coating concentration to adjust the coating amount at the time of painting. However, this has the problem of reducing the range of the coating amount control, and the coating concentration is changed at the time of painting. There is a case. Therefore, it is necessary to know the concentration of the paint when painting on a continuous line.

  On the other hand, conventionally, when the liquid concentration is changed, the liquid is often sampled offline to measure the concentration. As a concentration measuring method, a method of performing chemical analysis of a sampled liquid from a relatively simple method such as liquid specific gravity and viscosity is performed.

  However, in the case of liquid specific gravity, if there are many substances such as a state where they are dispersed without being dissolved, the change in specific gravity is small, so that it is difficult to detect the difference when the concentration changes. In addition, in the case of viscosity, there are problems such as errors due to temperature and large variations among drug lots.

  Furthermore, in chemical analysis, it is necessary to change the element to be measured each time the drug is changed. In offline measurement, it takes time, and the measurement becomes discontinuous, resulting in insufficient accuracy and subsequent feedback delay. There was a problem. On the other hand, for the on-line measurement in the chemical measurement, there is a problem that the equipment cost is increased in order to make the equipment capable of measuring a plurality of elements according to the paint.

As a method for automatically controlling the sugar content, for example, there is a technique disclosed in Patent Document 1. In this technique, the control means is configured to reduce the difference based on the difference between the detected sugar content value of the continuous sugar content meter that continuously detects the sugar content of the product delivered from the mixing means and the set target sugar content value. The rotational speed adjusting means of the positive displacement pump that feeds the stock solution and water separately to the mixing means is automatically controlled. Because of this, it is said that there is an effect that a product having the target sugar content can be produced extremely efficiently, easily and accurately as compared with a mixing apparatus that adjusts the sugar content by a conventional batch method.
Japanese Patent Laid-Open No. 6-98728

  However, in the technique disclosed in Patent Document 1, control to the target sugar content is ensured, but level control of the tank to be mixed is not performed. For this reason, when it is in a full state, it is necessary to wait until the level decreases, and if the target sugar content and the current value are separated during that time, there is a possibility that control becomes impossible. Furthermore, there is a problem that it is not possible to adjust the temperature of the mixed liquid when it is necessary.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paint concentration control system and method capable of performing paint concentration control while performing tank level control and temperature control.

  The present inventors have intensively studied an on-line concentration meter for paint that can be analyzed on-line and are relatively inexpensive, and have come up with the idea of using a saccharimeter, and devised the present invention. In other words, the saccharimeter is a general-purpose device that uses the refractive index, is available at low cost, and the refractive index changes depending on the components contained in the paint, so it can be used to manage the concentration of drugs with a fixed component ratio. I thought it might be. And as a result of examination, it was found that it can be sufficiently used for measuring the dilution rate of the paint.

  The invention according to claim 1 of the present invention is a chemical concentration control system that mixes a stock solution and a thin solution and adjusts to a predetermined sugar content, and stores a stock solution tank that stores the stock solution, a thin solution, a thermometer A thin solution tank having a liquid and a solution sent from the thin solution tank and the stock solution tank via a pump are mixed and stored, and the stored solution is discharged out of the system via a discharge valve or sent to a subsequent stage. A mixing tank, a solution fed from the mixing tank and the thin liquid tank via a pump, respectively, and stored, and the stored chemical solution is supplied to a line or fed back to the mixing tank via a pump A tank and a general control device, and the mixing tank and the supply tank each have a sugar meter, a level meter, and a thermometer, and these measured values The overall control device is a chemical concentration control system that controls the sugar content of a chemical solution while performing level control and temperature control of the mixing tank and supply tank by adjusting the pump and discharge valve. is there.

  According to a second aspect of the present invention, in the chemical concentration control system according to the first aspect, in adjusting the pump and the discharge valve, either the operation / stop of the pump or the opening / closing of the discharge valve is performed. This is a chemical concentration control system.

  The invention according to claim 3 of the present invention is a chemical concentration control method for mixing a stock solution and a thin solution to adjust the sugar content to a predetermined sugar content, and mixing and storing the stock solution and the thin solution and discharging them outside the system. Alternatively, the sugar content, level, and temperature are measured in a mixing tank that is supplied to the subsequent stage, and a supply tank that mixes and stores the solution from the mixing tank and the diluted solution and supplies the mixed liquid to the line or feeds back to the mixing tank. Then, the chemical solution concentration control method is characterized in that the sugar content of the chemical solution is controlled while performing level control and temperature control by adjusting the supply / discharge / feedback based on these measured values.

  In the present invention, the sugar content, level, and temperature are measured in each of the mixing tank and the supply tank, and the supply / discharge / feedback to / from the system is adjusted based on these measured values. While performing the control, the concentration control of the paint can be accurately performed.

  FIG. 1 is a diagram showing a configuration example of a paint concentration control system according to the present invention. In the figure, 1 is a stock solution tank, 2 is a thin solution tank, 3 is a mixing tank, 4 is a supply tank, 5 is a stock solution supply pump, 6 is a thin solution supply pump (1), 7 is a mixed solution supply pump, and 8 is a thin solution. Liquid supply pump (2), 9 is a mixing tank return pump, 10 is a sugar meter (1), 11 is a level meter (1), 12 is a thermometer (1), 13 is a sugar meter (2), 14 is a level meter (2) and 15 are a thermometer (2), 16 is a thermometer (3), and 17 is an overall control device and a discharge valve 18, respectively.

  There are a stock solution tank 1 and a thin solution tank 2 for storing a stock solution and a thin solution, respectively. These two solutions are mixed in a mixing tank 3 for mixing by a stock solution supply pump 5 and a thin solution supply pump (1) 6, respectively. The liquid is sent. The thin liquid tank 2 is provided with a thermometer (3) 16. In the mixing tank 3, a sugar content meter (1) 10, a level meter (1) 11, and a thermometer (1) 12 are installed, and these physical quantity data are monitored by an overall control device 17.

  Next, the solution mixed in the mixing tank 3 is sent to the supply tank 4 by the mixed liquid supply pump 7. At the same time, the diluted solution is supplied from the diluted solution tank 2 to the supply tank 4 by the diluted solution and diluted solution supply pump (2) 8. The supply tank 4 is provided with a sugar content meter (2) 13, a level meter (2) 14, and a thermometer (2) 15. These physical quantity data are transmitted to the overall control device 17 and approach the target value. So that it is automatically controlled. From the supply tank 4, there is a route for returning to the mixing tank 3 by the mixing tank return pump 9 in addition to the liquid feeding to the line. This will be described in detail later.

  Next, a control flow in which the sugar content, the liquid level and the temperature of the supply tank are kept constant by the above system configuration will be described with reference to FIGS. The target values of sugar content, level, and temperature controlled in the supply tank are Ct, Tt, and Lt, respectively.

  In the mixing tank 3, level control is performed so that the level falls within a certain range. When the lower control level is divided, the liquid is supplied from the stock solution tank 5 and the thin solution tank 6 to the upper control limit by operating the thin solution supply pump (1) 6 and the stock solution supply pump 5 until the control upper limit is reached. When the control upper limit of the level is reached, the operation of the thin solution supply pump (1) 6 and the stock solution supply pump 5 is stopped (FIG. 2 (a)).

  About a mixing ratio, it supplies with a fixed ratio. As the pump, it is desirable to use a metering pump that sends a constant flow rate. When the pump is not used, it is conceivable to control the flow rate by using a flow meter (not shown). In addition, at the time of supply, it supplies slowly so that the value Cm of the sugar content meter of the mixing tank 3 may not change rapidly.

  If the control upper limit of the level of the mixing tank 3 is exceeded, the dilute solution supply pump (1) 6, the stock solution supply pump 5 and the mixing tank return pump 9 are stopped, and if the level emergency upper limit is reached. Then, the discharge valve 18 is opened, and the liquid is discharged until the upper limit of the level control is reached (FIG. 2 (b)).

  In the mixing tank 3, the value Cm of the sugar content meter must not be smaller than the sugar content Ct controlled by the supply tank, and an alarm is issued when Cm / Ct is out of the predetermined value range (FIG. 2 ( c)). Although this predetermined value changes with subjects, it is generally desirable to set it as 1.2-1.5.

Next, control in the supply tank 4 will be described with reference to FIG. In the supply tank 4, automatic control of sugar content, liquid level, and temperature is performed. The measured values of the sugar content meter, the level meter, and the thermometer in the supply tank 4 are Cs, Ls, and Ts. In the automatic concentration control, the sugar content measurement value Cs and the target value Ct are compared. If Ct is larger, the pump 7 is operated and the liquid is fed from the mixing tank 1. On the contrary, if Cs is larger, the pump 8 is operated and the liquid is fed from the thin liquid tank 2. Assuming that the amounts of liquid to be fed are F _7C and F _8C , respectively, F _7C and F _8C are as follows (the front stage in FIG. 3B).

When Ct> Cs
F _7C = (Ct−Cs) / Cm × α
When Cs> Ct
F _8C = (Cs−Ct) × β
Here, α and β are constants preset in the overall control apparatus.

For the automatic liquid level control, the supply tank 4 is provided with a control lower limit, and when it falls below the control lower limit, replenishment is performed from the mixing tank 3 and the diluted liquid tank 2. For replenishment, the replenishment amount F _7L from the mixing tank 3 is fixed (a constant set in the overall control device), and the replenishment amount 2F _8L from the thin liquid tank is calculated from the following formula using the sugar content Cm and the target sugar content Ct of the mixing tank. To derive.

_F8L = _F7L * (Cm-Ct) / Ct
Accordingly, the totals F7 and F8 of the liquid feeding amount from the mixing tank and the liquid feeding amount from the thin liquid are obtained as follows (middle stage in FIG. 3B).

F7 = _F7C + _F7L
F8 = _F8C + _F8L
However, when the supply tank 4 is full, no more liquid can be fed and control becomes impossible. To prevent this, when the liquid level of the supply tank exceeds a certain upper limit, the mixing tank return pump 9 Is fed back to the mixing tank 3 (FIG. 3A).

  The supply tank 4 performs temperature control. A pipe (not shown) is passed through the side surface of the supply tank 4, hot water or cold water is passed through the pipe, and heat exchange is performed to control the temperature of the solution in the supply tank to be constant. Specifically, control is performed by adjusting the flow rate of hot and cold water. In the present invention, a control valve (not shown) is installed, and the flow rate is controlled by the valve opening. When the amount F7, F8 of the mixing tank and the dilute solution is generated, the valve opening B is preliminarily determined using the following formula in consideration of the amount of heat brought in, because it is affected by the amount of the solution to be fed and the tank temperature. The temperature change is decreased (the latter stage in FIG. 3B).

B = ξ × F7 × Tm + ζ × F8 × Tk
Here, Tk is the temperature of the diluted liquid tank.

  By using the present invention as described above, the concentration control of the paint can be realized with high accuracy while performing the level control and the temperature control.

It is a figure which shows the structural example of the concentration control system of the coating material which concerns on this invention. It is a figure which shows the example of a control flow in a mixing tank. It is a figure which shows the example of a control flow in a supply tank.

Explanation of symbols

1 Stock Solution Tank 2 Dilution Solution Tank 3 Mixing Tank 4 Supply Tank 5 Concentration Supply Pump 6 Dilution Solution Supply Pump (1)
7 Mixing liquid supply pump 8 Diluting liquid supply pump (2)
9 Mixing tank return pump 10 Sugar meter (1)
11 Level meter (1)
12 Thermometer (1)
13 Sugar meter (2)
14 Level meter (2)
15 Thermometer (2)
16 Thermometer (3)
17 General control device 18 Discharge valve

Claims (3)

A chemical solution concentration control system that mixes a stock solution and a diluted solution to adjust to a predetermined sugar content,
A stock solution tank for storing the stock solution;
A thin solution tank for storing thin solution and having a thermometer;
A mixture tank that mixes and stores solutions sent from the thin solution tank and the stock solution tank via pumps, and discharges the stored solution out of the system via a discharge valve or sends it to the subsequent stage; and
A supply tank that mixes and stores solutions sent from the mixing tank and the thin liquid tank via pumps respectively, and supplies the stored chemicals to a line or feeds back to the mixing tank via a pump;
With overall control device,
Each of the mixing tank and the supply tank has a sugar meter, a level meter, and a thermometer, and based on these measured values, the overall control device adjusts the pump and the discharge valve to adjust the mixing tank and the supply tank. A chemical concentration control system that controls the sugar content of a chemical while performing level control and temperature control. In the chemical | medical solution concentration control system of Claim 1,
In adjusting the pump and the discharge valve,
A chemical concentration control system that performs either operation or stop of a pump and opening / closing of a discharge valve. A method for controlling the concentration of a chemical solution by mixing a stock solution and a thin solution and adjusting to a predetermined sugar content,
A mixing tank that mixes and stores the stock solution and the diluted solution and discharges it to the outside of the system or supplies it to the subsequent stage; a solution from the mixing tank and the diluted solution that are mixed and stored; Measure sugar content, level, and temperature with the supply tank, and adjust the supply / discharge / feedback based on these measured values to control the sugar content of the chemical while performing level control and temperature control. The chemical | medical solution concentration control method characterized by these.

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