JPS6326036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling a cut gate that opens and closes an outlet of a storage tank storing materials such as aggregates.

As shown in FIG. 1, a storage tank (storage bin) 1 for materials such as aggregates is provided with a cut gate 3 operated by an air cylinder 2 at an outlet 1a.
Conventionally, in order to take out a predetermined weight of material, a comparator 6 is connected via an amplifier 5 to the weighing device 4a of the weighing hopper 4 provided below the take-out port 1, and the material falling from the take-out port 1 is connected to the weighing hopper 4. The comparator 6 compares the weight value of the material M with a predetermined weight value input into the comparator 6 in advance, and when these weight values become the same value, the air cylinder 2 connected to the comparator 6 A method has been used in which the control solenoid valve 7 is closed by the comparator 6 and the outlet 1a is closed by the cut gate 3.

However, if the cut gate 3 is closed when the measured value of the scale 4 becomes equal to the predetermined weight value as described above, the weight will come out from the outlet 1a and the weighing hopper 4.
This means that the material falling toward the target is ignored, and the weighing hopper 4 ends up containing material whose weight greatly exceeds the predetermined weight.

Conventionally, in order to eliminate such weighing errors, a set value S obtained by subtracting an error that is predicted to occur in advance from a predetermined weight value is input to the comparator 6, and this set value S is used by the cut gate 3. The measurement accuracy is improved by closing the outlet 1a.

However, the falling speed of the material falling from the outlet 1a varies greatly depending on changes in the amount of material stored in the storage tank, the particle size of the material, etc.
Even with this method, highly accurate measurements were not possible. In addition, the amount of material falling from the outlet 1a due to the delay in the operation of the air cylinder 2 or the solenoid valve 7 cannot be corrected by the conventional method described above, and micrometering less than this amount of falling is impossible with the conventional method. It was hot.

This invention opens and closes a cut gate provided at the outlet of a storage tank using an electromagnetic device for opening/closing control controlled by an arithmetic unit, and charges less material than a set value from the storage tank into a weighing hopper. The input amount is measured with a scale, and the calculation device calculates the input amount of material per unit time from the actual input amount and the opening/closing time of the cut gate, and based on the difference between the set value and the actual input amount and the above calculation result. To provide a control method for a cut gate which can accurately take out a predetermined weight of material from a storage tank, by opening and closing the cut gate again and putting the missing amount of material into a weighing hopper.

The present invention will be explained below with reference to the drawings.

FIG. 2 shows an example of a cutgate control device used in carrying out the present invention, and the same parts as those of the conventional device shown in FIG. Omitted.

In the figure, 1 is a storage tank (storage bin) for storing materials such as aggregates used in asphalt plants, and below this storage tank 1 is a weighing hopper 4 equipped with a measuring device 4a using a load cell or the like. It is being 7 is a solenoid valve (electromagnetic device for opening and closing control) for controlling the opening and closing of the air cylinder 2, 8 is a display device, and S is a set value input to the comparator 6 as in the conventional device shown in FIG. There is.

In the figure, numeral 10 indicates an arithmetic device whose input side is connected to the comparator 6 and into which the set value S is input, and whose output side is connected to the solenoid valve 7.
It is connected to the.

In addition, Fig. 3 shows the relationship between the energization time _T
This is a diagram shown in . In FIG. 3, T _φ indicates the delay time of the operation of the solenoid valve 7 and the air cylinder 2,
The slope of straight line A (fall amount per unit time) a is Δ
Q/ΔT, and the fall amount Q is expressed by the relational expression (T _x −T _φ )×a. In addition, in tests actually conducted by the present inventor, Q
It has been confirmed that the calculated relationship is as follows: =(T _x −T _φ )×a.

By the way, the arithmetic unit 10 has the above relational expression Q=
_{( T} The electromagnetic valve 7 is operated in terms of the energization time to 7, and the cut gate 3 opens and closes the outlet 1a.

Next, a case in which the method of the present invention is implemented using the apparatus shown in FIG. 2 will be described.

To take out the material of the set value S from the storage tank 1, first, the solenoid valve 7 is energized by the arithmetic unit 10 so that the material weighing 70 to 90% of the set value S is discharged from the takeout port 1a. . Here, the arithmetic unit 10 calculates the time to energize the solenoid valve 7 based on the input relational expression Q=(T _x -T _φ )×a, and energizes the solenoid valve 7 during this calculated time. Then, the solenoid valve 7 operates the air cylinder 2 to open the cut gate 3, and discharges the material weighing 70 to 90% of the predetermined amount from the port 1a. When the electromagnetic valve 7 is no longer energized, the air cylinder 2 closes the outlet 1a with the cut gate 3.

Next, the weight of the material put into the weighing hopper 4 is measured by the weighing device 4a, and this weighed value is input to the calculation device 10 by the comparator 6. Then, the calculation device 10
calculates the energization time to the solenoid valve 7 from the above relational expression based on the difference between the set value S and the above measured value, energizes the solenoid valve 7 for the calculated time, and then opens the outlet 1a again by the cut gate 3. Weigh the ingredients using the hopper 1
4.

After inputting the material, the weight of the material in the weighing hopper 4 is measured again using the weighing device 4a, and this measured value is again input into the calculation device 10, and if there is a difference with the set value S, the above relational expression is again calculated. Then, the solenoid valve 7 is energized.

The above operations are automatically performed by the comparator 6 and the arithmetic unit 10 until the difference between the measured value of the measuring device 4a and the set value S falls within the allowable range, thereby completing the measurement.

When weighing materials by controlling the cut gate 3 as described above, the actual weight of the material fed into the weighing hopper 4 is weighed, and the shortfall between the set value S and the material is fed later for final feeding. Since the amount is controlled by feedforward control, there is no measurement error caused by falling material. Therefore, it is possible to accurately take out a predetermined weight of material from the storage tank 1. Further, since it has been confirmed as above that the above-mentioned relational expression is correct in the micromeasuring section, the method of the present invention allows any minute amount of material to be taken out from the storage tank 1 accurately. Note that if the set value S is large,
Weighed using the conventional method with an error of about 50 kg,
Thereafter, the method of the present invention may be applied to weigh.

By the way, with the conventional method, the weighing error was around ±15 kg, but with the method of this invention, it is +0 ~
It is possible to weigh with an error accuracy of about -3 kg.

In addition, in the above-mentioned device, the cut gate 3
Although the cut gate 13 is operated by an air cylinder 12, the device for operating the cut gate 13 may be a mechanical device using a motor, gears, or the like.

As explained above, in the cutgate control method according to the present invention, the cutgate provided at the outlet of the storage tank is opened and closed by an electromagnetic device for opening/closing control controlled by an arithmetic unit so that the cutgate is lower than a set value. Pour the material from the storage tank into the measuring hopper,
The actual input amount is measured with a scale, and the calculation device calculates the input amount of material per unit time from the actual input amount and the opening/closing time of the cut gate, and calculates the difference between the set value and the actual input amount and the above calculation result. Based on the weight of the material actually taken out from the storage tank, the cut gate is opened and closed again to put the missing amount of material into the weighing hopper. A predetermined weight of material can be accurately taken out from the storage tank regardless of variations in the falling speed of the material falling from the tank to the weighing hopper or delays in the operation of electromagnetic equipment.

[Brief explanation of the drawing]

Fig. 1 is a block diagram for explaining the conventional cut gate control method, Fig. 2 is a block diagram for explaining the method of the present invention, and Fig. 3 shows the amount of material falling from the outlet of the storage tank and the cut gate. FIG. 3 is an explanatory diagram showing the relationship between the current supply time to the electromagnetic equipment for opening/closing control; 1... Storage tank (storage bottle), 1a... Outlet, 3... Cut gate, 4... Weighing hopper, 4
a...Measuring instrument, 7...Solenoid valve (electromagnetic equipment), 10
...Arithmetic device, M...Material.

Claims (1)

[Scope of Claims] 1. A cut gate provided at the outlet of the storage tank is opened and closed by an electromagnetic device for opening/closing control controlled by a computing device, and material less than a set value is introduced from the storage tank into the weighing hopper. Then, the actual input amount is measured with a measuring device, and the calculation device calculates the input amount of material per unit time from the actual input amount and the opening/closing time of the cut gate, and the difference between the set value and the actual input amount is calculated.
and a method for controlling a cut gate, characterized in that the cut gate is opened and closed again based on the above-mentioned calculation result, and the missing amount of material is put into a weighing hopper.