JPS63274438A - Liquid weighing and mixing apparatus - Google Patents

Abstract

PURPOSE:To perform a wide range of weighing within a short time with high accuracy, by a method wherein opening degree control valves are respectively provided to a plurality of supply containers while a liquid amount detector is provided to a liquid receiving container to control the opening degree control valves on the basis of an actually weighed value and a weighing set value. CONSTITUTION:For example, in a system for weighing and mixing two kinds of liquids, when a manufacturing condition is indicated to a weighing control apparatus 3, a weighing set value is set and valves 9, 19, 10 are changed over to a weighing system line. When a stopper valve 8 is opened and an opening degree control valve 7 is adjusted to a predetermined opening degree, the raw material of a tank 1 is transferred to a tank 2 and the wt. of the transferred raw material is detected by the load cell 4 of the tank 2 and the value thereof is fed back to the weighing control apparatus 3 through a load cell amplifier 5. The control apparatus 3 operates the deviation between the actual wt. value and the set value and the timewise change quantity of the deviation to issue a new opening degree order to the next control cycle. A tank 11 is also controlled in the same way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a liquid measuring and mixing device that prepares a new mixed liquid by measuring and mixing various types of raw material liquids.

(Prior art) Conventionally, as a measuring device applied to a liquid measuring and mixing device,
In order to achieve highly accurate metering, a metering device with a limited flow rate is used instead of one with a variable flow rate.

Furthermore, in conventional liquid measuring and mixing apparatuses, when liquid is supplied from a plurality of supply containers to one container, a measuring device is provided attached to each supply container.

For example, when using a volumetric measuring system, two measuring devices are used for two liquids, and a two-loop control function is used to predict and control the inflow amount, as shown in Figure 6. JP-A-56-74715 and JP-A-5111-163
Publication No. 426 discloses a "liquid preparation device" and a "liquid supply method," and although these publications sequentially measure the flow rate of each method using a common measuring device, a liquid preparation device is attached to each container. The liquid supply means for discharging the liquid are controlled by independent control loops.

That is, since the flow rate of the liquid varies depending on the amount of liquid in the supply container, the valve flow rate characteristics, the physical properties of the liquid, etc., highly accurate metering cannot be expected with the same control function.

This also applies to the tank metering system, and the shutoff valves of the actuators attached to each unit need to be controlled by independent loop control systems.

In addition, in order to achieve high-accuracy metering, there is a method of installing pulps with different flow rates in parallel and switching at a predetermined metering deviation, but even in this case, two-loop control is required as a control function. .

Here, we use the expression 2-loop control function because, for example, when using a distributed control device, weighing can be processed within one control device, and two control devices are required. This is because it cannot be said that it is. However, in terms of the number of input/output points and software, it can be said that there are two control devices.

(Problems to be Solved by the Invention) Conventional liquid metering and mixing devices have the following drawbacks because the metering control is based on a constant flow rate.

■ Weighing accuracy: Accuracy may not be guaranteed due to fluctuations in flow velocity due to disturbances or changes in liquid physical properties.

In other words, in the case of gravity transfer, the flow rate of the outflowing liquid varies depending on, for example, the amount of liquid remaining in the supply side container, but if the change in the remaining amount is large, the flow rate goes outside a certain condition range, resulting in poor accuracy.

In addition, this means that it is necessary to limit the amount of liquid in the supply side container to a certain level and ensure that the amount of liquid is always above a certain level.
This caused liquid loss and increased running costs.

■ Weighing range 2 The measuring range is narrow.

The reason for this is that even if the metering is stopped, there is still some inflow due to the response delay of the system, and this amount is determined by the flow velocity. Therefore, when the flow rate is constant, an acceptable inflow can be guaranteed by narrowing the measurement range. are doing. Therefore, even when measuring the same liquid, measuring devices each having an appropriate measuring range are required, and the number of devices increases.

■Measuring time: Measuring time is affected by the measurement settings.

If the metering setting value is small, the metering time will be short; if it is large, the metering time will be long. Therefore, a measuring device suitable for the manufacturing cycle is required depending on the measured value, and the number of devices increases.

Furthermore, in conventional liquid measuring and mixing apparatuses, for the reasons mentioned above, a large number of independently controlled measuring devices are installed for each supply container, and are installed at each optimum measuring time due to manufacturing capacity limitations. The system became complicated and a large number of measuring devices were installed.

The object of the present invention was achieved based on the above circumstances, and
A measurement control device that achieves high-precision measurement that is unaffected by flow rate fluctuations due to disturbances or changes in liquid physical properties, secures a wide measurement range, and realizes short-time measurement without being affected by the size of the measurement setting value. Using this, we can configure the system to simplify equipment, increase manufacturing capacity, and reduce raw material loss. ■ Reduce initial cost by reducing the number of devices ■ Reduce maintenance man-hours by reducing the number of devices ■! 7E Reducing failures by improving reliability by reducing the number of devices■ Our objective is to provide a liquid measuring and mixing device that is economically effective in reducing running costs by reducing raw material loss.

(Means for Solving the Problems) The above object of the present invention is to apply a metering control device that changes the flow rate from time to time by closed loop control when measuring a liquid to be measured, and to provide equipment for the metering control device. This is achieved by using liquid measuring and mixing devices that can reduce the number of devices. Therefore, the liquid measuring and mixing device of the present invention is constituted by the following components.

l) Supply container: container that stores the liquid to be metered.

The capacity of the container is determined by the scale suitable for manufacturing. Requires a tool.

In the present invention, the limit on the remaining amount of the container is Theoretically, the remaining amount can be weighed to 0. Also, the physical property values of the liquid (e.g. Possible to flow out without being affected by viscosity, etc.) If it has liquid physical property values, It is possible to measure even liquids up to the remaining amount O. Ru.

2) Opening adjustment valve: This is a flow rate control valve that has opening adjustment valves corresponding to the number of supply containers, and changes the flow rate by changing the opening of the valve.

As a drive, for example, AC servo There are motors etc.

3) Switching device: This is a device for controlling multiple opening adjustment valves with one drive control device. Although it is not necessary if each opening adjustment valve has a drive control device, it is used to reduce costs. It may be installed in

4) Metering control device! = It is a closed-loop controlled precision metering control device that changes the flow rate, and one metering device performs each method of metering.

One unit can handle multiple liquids in the same container. It can be measured with a weighing device, and The number of locations can be reduced.

5) Receiving container: A container with the capacity to pass through the manufacturing scale.

For miscible liquids, cumulative Measure by volume.

Mixing is possible by cleaning after each measured liquid transfer. Even if this is not possible, place them separately in the same container. It can be weighed by

Stirring and mixing can also be done in this container. It is possible.

The basic components of the present invention are as described above, but the basic component is the use of a closed-loop metering control device that varies the flow rate, and various auxiliary devices may be installed.

For example, a spray ball or the like is installed in each container for cleaning, and a switching valve is installed in the middle of the piping. Also, install a stirrer in each container for mixing. Additionally, hot water from a constant temperature bath, etc. will be circulated to maintain heat.

(Embodiment) Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

One embodiment of FIG. 1 shows a two-liquid metering and mixing system. In other words, this system transfers raw material liquid from two tanks serving as supply containers placed on the upstream side and supplies it to one tank serving as a liquid receiving container placed on the downstream side. Two liquids are cumulatively measured and mixed.

The two upstream tanks 1.11 are equipped with drain valves (D
RV) 9.19 and S)-/Phalbu (SPV) 8
．． 18 are connected to the piping lines 12 and 13, respectively, and the DRVs 9 and 19 each have an opening adjustment valve (
FCV)? , IT is attached and provided.

The piping lines 12 and 13 are connected to a common connecting pipe O placed at the end, and are connected to a cleaning/waste pulp (CVD) 10.
The liquids can be transferred to the tanks 2 on the downstream side via the respective tanks. Further, a cleaning start valve (CIV) 14 and an air vent valve (ADV) 15 are arranged on the upstream side of the connecting pipe 20, and the cleaning liquid passes through the CIV 14 to the connecting pipe J.
It is provided so that it can be introduced into O.

A load cell 4 as a detector for measuring the weight of the liquid to be measured is arranged in the tank 2 on the downstream side. The load cell 4 is connected to the weighing control device 3 through a load cell amplifier 5.

The metering control device 3 is connected to a switching device 16 via a servo driver 6.

The switching device 16 is connected to an opening adjustment valve 7.17 and a stopper valve 8.18 arranged in the two liquid supply systems, respectively, and is connected to the opening adjustment valve 7.17 and the stopper valve 8.18 arranged in the two liquid supply systems.
Switch between two systems.

The operation process of the liquid measuring and mixing device configured in this way will be explained.

Manufacturing conditions (conditions for measuring the liquid in tank 1, then measuring the liquid in tank 11, etc.) are specified to the metering control device 3.

The measurement setting value is set in the measurement control device 3, and DRV9.1
9. CDVIO is called out to the measurement system line. When the start of metering is instructed, PV 8 is opened, and a position command is transmitted from the metering control device 3 to the servo driver 6 so that the FCV 7 has a predetermined opening degree, and the servo motor is driven to receive the instruction. The valve port of FCV7 is set to the position shown in FIG.

The load cell of the tank 2 detects the weight of the transferred raw material and feeds back the value to the weighing control device 3 through the load cell amplifier 5.

The weighing control device 3 calculates the deviation from the set value and the time change amount of the deviation from this fed-back actual weight value, and performs the next control based on one of the control methods of fuzzy control, optimal control, and learning control. Calculate the opening command (position command) that will give an appropriate flow velocity in the cycle. Then, in the next control cycle, a new opening degree command (position command) is given to the FCV 7 to change the flow velocity.

As described above, based on the observed amount of the load cell 4, the opening degree of the FCV 7 is controlled in a closed loop at a predetermined control cycle, and as a result, the flow velocity is controlled.

When the metering deviation becomes smaller, the FCV 7 narrows its opening and becomes a minute flow velocity. When the weighing deviation and the amount of time change in the weighing deviation become smaller and the weighing deviation becomes less than a certain value, the weighing stops and the
PV8 is closed, and FCV7 moves in the fully closed direction. At this time, the flow velocity is minute and the amount of inflow is minute.

Therefore, the amount of flow after the metering decreases becomes smaller, and the metering accuracy improves regardless of flow velocity fluctuations. Furthermore, in the measurement range, the operation of the FCv7 changes depending on the measurement setting value and the process system, and the same measurement device can perform measurement regardless of the size of the measurement setting value, expanding the measurement range. However, it is within the static accuracy of the detection end. Also, during the measurement time, FCV7
The operation pattern changes, regardless of the size of the weighing set value.
It is possible to perform the same measurement in a short time.

Next, the process switches to measuring the liquid in the tank 11. Switching device 1
6 to FCV 17 on the tank 11 side. The measurement setting value is set in advance, and the same control as above is performed in accordance with the measurement start command to perform measurement. The control functions within the control device are the same, and only the output signals to the FCV 17 and 5PV 18 of the operating end are switched by the switching device 16.

The liquid is transferred to the tank 2 through the connecting pipe Q.

The meaning of this connecting pipe is to increase the diameter of the pipe and allow the remaining liquid in the pipe to fall naturally. Therefore, in order to improve measurement accuracy, it is necessary that the length of this connecting pipe be as short as possible. However, there is also a method of connecting to the tank 2 by piping each separately without using the main connecting pipe. In this case, since the size of the tank 2 is finite, the amount of liquid to be mixed is limited, and in addition, when receiving multiple liquids, there are equipment problems such as difficulty in piping configuration. This is advantageous for ultra-high precision metering where the amount remaining in the tube is a problem.

The present invention is an example of additive metering (method of storing and measuring liquid in a metering tank), and DRV9, 19 in the figure.
, CDVIOlCI V14 (cleaning start valve), ADV
15 (air bleed valve) is a valve for incidental cleaning, waste liquid, etc.

Therefore, for example, when measuring the liquid in tank 1, cleaning after that, and then measuring the liquid in tank 11, if only the connecting pipe is cleaned after measuring the liquid in tank 1, C.
Switch the DVIO to the waste liquid side and open the CIV14 for cleaning. At this time, ADV15 is closed, 5pvs and 5PV1B
Also closed. After cleaning for a certain predetermined time, CIV 14 is closed and ADV 15 is opened. After that, ADV15
is closed and the next tank 11 is weighed.

Next, the results of measurements carried out using the apparatus shown in FIG. 1 and based on the process described above will be shown.

The resulting weighing device can weigh up to 10 kg, and the accuracy of the load cell is 1/500. The position of the FCV (opening adjustment valve) is controlled by a servo motor, and a position command is output from a metering control device.

FIG. 4 shows the flow rate characteristics of two types of opening adjustment valves.These two types of opening adjustment valves were installed in the system shown in FIG. 1, and measurement was performed without changing the control method or the like.

Figure 5 shows the 1000 g weighing result at that time.
-a is the result of the opening adjustment valve having the flow rate characteristic of FIG. 4-a, and FIG. 5-b is the result of FIG. 4-b.

As is clear from FIG. 5, although the operation pattern of the opening degree of the opening adjustment valve changes, highly accurate measurement was obtained in approximately the same measurement time.

In experiments using this system, the same liquid was used, and the flow characteristics of the opening adjustment valve were varied to evaluate the effects of differences in liquid physical properties. Furthermore, experiments were also conducted with different liquid volumes in the upstream tank. As a result, we were able to confirm high accuracy, wide range, and short time metering by simply switching to the predetermined opening adjustment valve and stop valve using the same control device.

Furthermore, in this measuring system, as shown in FIG. 4, the flow rate, that is, the flow rate, differs depending on the remaining amount of liquid even if the opening is the same. However, although the remaining amount of liquid was measured at each level, although the operation pattern of the valve opening was different, the same results were obtained in terms of measuring time and measuring accuracy. Also, regarding the measurement range,
In the range of 1:1OO, ±1. Accuracy within 0g was guaranteed.

In the embodiment described above, a case was described in which two liquids were measured and mixed, but in the present invention, a large number of liquid types may be measured in the same liquid receiving container. However, in terms of the system, it is desirable that the number of opening adjustment valves controlled by the same metering device be about eight.

Next, the most general aspect of the invention will be described.

FIG. 2 is a control block diagram of a device applied to cumulative metering of multiple liquids, and this device has N opening adjustment valves and N shutoff valves attached to N supply containers. Each of the valves selected by the switching device is opened and closed by a drive motor driven by commands from the metering control section and the drive control section. For each cumulative weighing method, the actual weight value is measured by a load cell, and this value is fed back to the weighing control section.

As a modification of the present invention, it is also possible to combine the addition measurement method in which a detector is installed in the liquid receiving container to measure the liquid, and the subtraction measurement method in which a detector is installed in the supply container to measure the amount of liquid flowing out. .

FIG. 3 shows a control block diagram of the above modification. That is, in the figure, the measuring tank N indicates the supply container,
The outflow amount of the liquid filled in this container is measured by a load cell N, and the liquid is transferred to a liquid receiving container indicated by a measuring tank A, and cumulatively measured by a load cell A. The binary values obtained by the subtraction metric and cumulative metric are fed back to the respective metric control sections. The metering control section calculates a deviation and a time change amount of the deviation between the set metering setting values, and outputs an opening command based on fuzzy control or the like. The outputs of the two metering control sections are switched by a control method switching device to control the drive control section.

With the above configuration, for example, by performing minute measurements using subtraction weighing and weighing items with large measurement settings using additive weighing, it is possible to perform measurements over a wider measurement range.

Furthermore, in a solution-only manufacturing system, if a measuring tank is equipped with an agitator, a hot water circulation device, etc. as incidental equipment and positioned as a preparation tank, measuring, mixing, reaction, etc. can be performed in the same container.

In addition, in the above embodiment, a load cell was used as an example of a detection device for measurement, but other detectors can also be used.For example, pressure detectors such as differential pressure transmitters, various level meters, etc. There is. Note that here, the measurement range differs depending on the static accuracy of the detector.

Further, although a servo motor has been described as an example of a drive device for the opening adjustment valve, any device that can control the position may be used.

(Effects of the Invention) As described above, according to the liquid measuring and mixing device of the present invention, by applying a measuring device that is not affected by the measurement setting value, residual liquid amount, liquid physical properties, etc., ■ Reduction in the number of measuring devices ■ Since loss can be reduced, the following economic effects can be obtained.

■ Reducing initial costs by reducing the number of devices ■ Reducing maintenance errors by reducing the number of devices ■ Reducing failures by improving reliability by reducing the number of devices ■ Because of flow rate control, it is not affected by the remaining amount of raw material (head difference), etc. Reducing running costs by reducing raw material loss

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a two-liquid meter device according to an embodiment of the present invention, FIG. 2 is a control block diagram illustrating a multi-type ridge mixing device according to the present invention, and FIG. 3 is a control block diagram according to a modification of the invention. 4 are flow characteristic diagrams of the opening adjustment valve applied in the song metering experiment using the device shown in FIG. 1 based on the invention, (a) is the high flow velocity type, Figure 5 is a diagram showing the actual measurement results, and (a) and (mountain) are shown in the first diagram (corresponding to al and (bl), respectively, and the sixth diagram is the conventional one). It is a configuration diagram showing the device. 1.11... Upstream tank (supply container), 2... Downstream tank (liquid receiving container), 3... Metering control device, 4...
-Docell, 5... Load cell amplifier, 6... Servo motor, 7.17... Opening adjustment valve (FCV), 8
゜...Stopper valve, 9.19...Drain valve (RV'), 10...Washing/waste valve (CD)
v), 1213... Piping line, 14... Cleaning start valve (
CIV), 15...A release valve (ADV>, 16...
Switching device, CO...Connection Figure 4 (a) (b)? M (mm) Fig. 5 1τt II h+ Cstg ttf al U (sec)

Claims (1)

[Claims] 1) A liquid measuring and mixing device that cumulatively measures and mixes multiple liquids using a closed-loop liquid measuring method that changes the flow rate, comprising at least two or more supply containers and each supply container. a liquid receiving container for mixing the liquid transferred from the liquid receiving container; an opening adjustment valve disposed between the supply container and the liquid receiving container and attached to each supply container to control the flow rate; and an opening adjustment valve attached to at least the liquid receiving container. a detector that measures the amount of liquid; a metering control device that calculates a flow rate control amount based on the actual measured value measured by the detector and the metering setting value; and a metering control device that adjusts the output of the metering control device to the opening degree. A liquid measuring and mixing device characterized by comprising: a switching device that switches to each valve and outputs the output. 2) The metering control device shall calculate the amount of change in flow velocity using one of the following control methods: fuzzy control, learning control, or optimal control from the deviation between the arbitrarily set metering value and the actual metering value and the amount of deviation time change. A liquid measuring and mixing device according to claim 1, characterized in that: 3) The first claim is characterized in that the process from measurement to reaction is performed in the same container by installing ancillary equipment for preparation in the liquid receiving container so that it can also be used as a preparation container.
The liquid metering and mixing device described in Section.