JPH01247326A - Method and device for supplying fixed quantity of liquid or slurry - Google Patents

Abstract

PURPOSE:To enable a supply amount of liquid or slurry per unit time to be maintained to a fixed value by calculating a surface level of the liquid or the slurry in a storage tank by a control unit and simultaneously increasing the opening degree of an opening and closing valve in accordance with a decrease of the level. CONSTITUTION:A control unit 10, when it inputs a supply request from a mixer in a rear stage, outputs a control signal to an opening and closing valve 4, opening it. Then liquid or slurry in a storage tank 1 is supplied by its gravity to the mixer through a supply pipe 3. Here the control unit 10 calculates a surface level of the liquid or the slurry in the storage tank 1 by a detecting output from a weight detector 2, controlling the opening and closing valve 4 in its opening in accordance with the level. Accordingly, the level is lowered following a progress of supply of the liquid or the slurry, decreasing a supply pressure, but the opening and closing valve 4 increases its opening in accordance with the decrease of the supply pressure, maintaining a flow of supply to almost a fixed value. And in the point of time almost 95% the total supply amount is supplied, the control unit 10 controls the opening of the opening and closing valve 4 in accordance with the level.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for quantitatively supplying a liquid or slurry and a constant QIjL supply device.

(Prior art and its problems) When supplying a fixed amount of liquid or slurry stored in a storage tank to, for example, a mixing device using gravity, in order to achieve good mixing, the total amount supplied at one time must be adjusted to a predetermined amount. In some cases, it is absolutely necessary not only to keep the supply amount constant, but also to maintain the supply amount per unit time constant during supply.

However, while this requirement can be achieved relatively easily using rotary feeders, screw conveyors, etc. when supplying powder or granules in a fixed quantity, when supplying liquids or slurry in a fixed quantity, the storage tank needs to be filled as the supply progresses. There is a problem that the liquid level in the liquid or slurry gradually decreases and the supply pressure decreases, resulting in a decrease in the supply amount per unit time. There wasn't.

(Means for Solving the Problems) In order to solve the above problems, the method for quantitatively supplying liquid or slurry of the present invention provides a method for quantitatively supplying liquid or slurry stored in a storage tank by gravity through a supply channel. In this case, by detecting the liquid level of the liquid or slurry and increasing the cross-sectional area of the supply channel according to the decrease in the liquid level, the supply per unit time can be increased regardless of the decrease in the liquid level. The amount is kept constant.

Further, the liquid or slurry quantitative supply device of the present invention includes a storage tank for storing the liquid or slurry, a weight detector for detecting the weight of the storage tank, and a weight detector connected to the bottom of the storage tank to detect the amount of liquid in the storage tank. Alternatively, a supply pipe that supplies slurry to a predetermined location, an on-off valve that is interposed in the supply pipe and whose valve opening degree can be arbitrarily varied, and a valve of the on-off valve that opens based on a detection signal from the weight detector. When supplying liquid or slurry, the control device calculates the liquid level of the liquid or slurry in the storage tank, and at the same time, the opening/closing is performed according to the decrease in the liquid level. By increasing the opening degree of the valve, the supply amount per unit time is maintained constant.

(Function) According to the liquid or slurry quantitative supply method of the present invention,
The liquid or slurry level is detected and the cross-sectional area of the supply flow path is increased according to the drop in the liquid level, so even if the supply pressure decreases due to a drop in the liquid level, the Since the cross-sectional area of the flow path increases, the amount of supply per unit time is maintained constant.

Further, according to the liquid or slurry quantitative supply device of the present invention, when supplying the liquid or slurry, the control device:
The liquid level of the liquid or slurry in the storage tank is calculated, and at the same time the valve opening of the on-off valve is increased according to the drop in the liquid level, so even if the supply pressure decreases due to a drop in the liquid level, Since the cross-sectional area of the flow path of the on-off valve increases accordingly, the supply amount per unit time is maintained constant.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

FIG. 1 is a schematic diagram of a quantitative supply device for liquid or slurry according to an embodiment of the present invention. Reference numeral 1 denotes a storage tank for storing a liquid or slurry such as an additive, and this storage tank 1 has both upper and lower ends. It is closed and almost cylindrical. Storage W
A hole (not shown) for communicating the inside of the storage tank 1 with the atmosphere is provided at the upper end of the storage tank 1, and the lower end of the storage tank 1 is tapered into an inverted conical shape. The storage tank 1 is supported by a pedestal (not shown) via a weight detector 2 such as a load cell, and has a supply pipe 3 at its lower end for supplying the internal liquid or slurry to the next stage, such as a mixing device. is connected. An on-off valve 4 is interposed in the supply pipe 3 at a position near the lower end of the storage tank 1, and the opening degree of this on-off valve 4 can be freely varied by an electrical control signal. A stirring device 5 for stirring the liquid or slurry is attached to the storage tank 1, and the stirring device 5 includes an electric motor 6 with a speed reducer installed above the storage tank 1, and a storage tl! in the storage tel! y1
The rotating shaft 7 is located concentrically with the rotary shaft 7 and rotationally driven by an electric motor 6, and a plurality of stirring blades 8 are fixed to the rotating shaft 7. A charging pipe 9 for charging liquid or slurry into the storage tank 1 is connected to the upper end of the storage tank 1 . The weight detector 2 is electrically connected to an input end of a control device 10, and an output end of the control device 10 is electrically connected to a control signal input end of the on-off valve 4.

The control device 10 is constituted by, for example, a microcomputer, and calculates the liquid level of the liquid or slurry in the storage tank 1 based on the detection signal from the weight detector 2. In other words, the detection output from the weight detector 2 corresponds to the weight of the storage tank 1 containing the liquid or slurry inside.
Since the weight of the empty storage tank 1 itself is known in advance, the weight of the liquid or slurry can be easily calculated. Also, storage tank 1
Since the shape and dimensions of the liquid or slurry are known in advance, the specific gravity of the liquid or slurry can be determined in advance by Δl! By inputting a constant value into the control device 10, the liquid level can be easily calculated from the weight of the liquid or slurry. Note that the relationship between the weight of the liquid or slurry and its liquid level may be manually entered into the control device 10 as data in advance. Said on-off valve 4
Although not shown, the valve body is composed of, for example, a perforated valve body, a pneumatic cylinder device that rotationally drives the valve body, and a solenoid valve that controls compressed air to the pneumatic cylinder device. The solenoid valve is actuated by a control signal from the control device 10 to control the pneumatic cylinder device, which causes the valve body to rotate and change the cross-sectional area of the flow path formed by the hole in the valve body. .

FIG. 2 is an explanatory diagram of the relationship between the opening degree of the on-off valve 4 and the flow rate of liquid or slurry flowing through the supply pipe 3, where the horizontal axis represents the valve opening degree and the vertical axis represents the flow rate. Solid line A indicates when the liquid or slurry level in storage tank 1 is 700 mm, solid line B indicates when the liquid level is 350 mm, and solid line C indicates when the liquid level is 5 mm.
The case of 0 mm is shown in each case. From FIG. 2, it can be seen that if it is desired to maintain the supply flow rate at, for example, 25 cubic meters per hour, the opening degree of the on-off valve 4 can be controlled as indicated by the solid line in FIG. Also, if you want to maintain the supply flow rate at 3 cubic inches per hour, for example, as shown by the solid line E in Figure 3, the on-off valve 4
It can be seen that it is sufficient to control the valve opening degree of . In FIG. 3, the horizontal axis represents the opening degree of the on-off valve 4, and the vertical axis represents the liquid level of the liquid or slurry in the storage tank 1.

Next, the effect will be explained. The liquid or slurry introduced into the storage tank 1 through the input pipe 9 is stirred continuously or as appropriate by the stirring device 5. When a supply request is input to the control device 10 from, for example, a mixing device in a subsequent stage, the control device 10 outputs a control signal to the on-off valve 4 to open the on-off valve 4. Thereby, the liquid or slurry in the storage tank 1 is supplied to a subsequent stage, for example, a mixing device, through the supply pipe 3 under the action of gravity. At this time, the control device 10 calculates the liquid level of the liquid or slurry in the storage tank 1 based on the detection output from the weight detector 2, and according to the liquid level, opens and closes the valve as shown by the solid line in FIG. Controls the valve opening degree of 4.

Therefore, as the supply of liquid or slurry progresses, the liquid level decreases and the supply pressure decreases, but the opening degree of the on-off valve 4 increases accordingly and the cross-sectional area of the supply flow path increases. Therefore, the feed flow rate is maintained at approximately 25 cubic meters per hour. When, for example, approximately 95% of the total supply amount has been supplied, the control device 10 controls the on-off valve 4 according to the liquid level.
The valve opening degree is controlled as shown by the solid line E in FIG. As a result, the supply flow rate is maintained at approximately 3 cubic meters per hour. When a predetermined supply amount is supplied, the control device 10 closes the on-off valve 4. At this time, 95% of the total supply amount is supplied. Since the supply flow rate is reduced from 25 cubic meters per hour to 3 cubic meters per hour at this point, the error in the total supply amount due to errors in the closing timing of the on-off valve 4 is extremely small, and the predetermined supply amount can be accurately controlled. Can be supplied.

In this way, a constant supply flow rate can be maintained regardless of the drop in the liquid level, so that, for example, mixing in the subsequent mixer, which is the supply destination, can be performed extremely well.

Further, as in this embodiment, it is very preferable to reduce the supply flow rate at the final stage of supply, since it is possible to accurately supply a predetermined supply amount.

(Another Example) In the above example, a microcomputer was used as the control device 10, but the present invention is not limited to such a configuration. For example, the specific gravity of liquid or slurry, the supply flow; If there is no need to vary the supply amount or the like, the control device 10 can be easily configured using an analog electronic circuit.

Further, in the above embodiment, an example in which the stirring device 5 is provided in the storage tank 1 has been described, but the stirring device 5 may be provided only when it is necessary to stir the liquid or slurry.

Further, in the above embodiment, the liquid level of the liquid or slurry in the storage tank 1 was detected by determining the weight of the storage tank 1 by dl11, but the method for quantitatively supplying the liquid or slurry of the present invention is not limited to this. For example, instead of using a device that uses a level meter, it may be directly detected using a level meter or the like.

(Effects of the Invention) As explained above, according to the present invention, the cross-sectional area of the supply channel is increased in accordance with the decrease in the liquid level of the liquid or slurry, so that the unit regardless of the decrease in the liquid level The amount of supply per hour can be maintained constant. In addition, according to the liquid or slurry quantitative supply device of the present invention, the liquid level is detected using the weight detector necessary for determining the supply amount, so there is no need to provide a separate level meter, etc., and the cost is reduced. You can try to bring it down.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a quantitative supply device for liquid or slurry according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the relationship between the opening degree of an on-off valve and the flow rate of liquid or slurry flowing through a supply pipe. FIG. 3 is an explanatory diagram of the relationship between the opening degree of the on-off valve for keeping the flow rate constant and the liquid level of the liquid or slurry in the storage tank. 1...Storage tank, 2...Heavy Hi detector, 3...Supply pipe, 4...Opening/closing valve, 10...Control device patent applicant 1" Agent of Hon Aluminum Industry Co., Ltd.
Patent attorney Tadataka Hishin [-・5. (- 31 days after the 11th

Claims (1)

[Claims] (1) When supplying a fixed amount of liquid or slurry stored in a storage tank through a supply channel by gravity, the liquid level of the liquid or slurry is detected, and the supply channel is adjusted according to the decrease in the liquid level. A method for quantitatively supplying a liquid or slurry, characterized by increasing the cross-sectional area of the flow path to maintain a constant supply amount per unit time regardless of a drop in the liquid level. (2) A storage tank that stores liquid or slurry, a weight detector that detects the weight of this storage tank, and a supply that is connected to the bottom of the storage tank and supplies the liquid or slurry in the storage tank to a predetermined location. a pipe, an on-off valve that is interposed in the supply pipe and whose opening degree can be arbitrarily varied;
and a control device that controls the opening degree of the on-off valve based on the detection signal from the weight detector, and when supplying the liquid or slurry, the control device controls the level of the liquid or slurry in the storage tank. Quantitative supply of liquid or slurry, characterized in that the supply amount per unit time is maintained constant by calculating the level and simultaneously increasing the opening degree of the on-off valve according to the decrease in the liquid level. Device.