JPH081391B2 - Loss-in-weight type constant flow rate supply device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loss-in-weight type of constant flow rate delivery device for delivering a raw material from a storage tank at a constant flow rate.

2. Description of the Related Art This type of loss-in-weight type constant flow rate supply device is
It is constructed as shown in the figure or FIG. The device shown in FIG. 3 is configured as follows. A vibration feeder 2 including a trough 2a and a vibration exciter 2b is attached to the bottom of the storage tank 1, and these are installed on a plate of a weighing device 3. The net net weight value G _S of the weighing device is input to the payout calculation unit 4. Here, the reduction weight ΔG of the weight value G _S per unit time is repeatedly calculated and integrated, and the accumulated weight G _{Tn of the} raw material actually discharged through the vibration feeder 2 by the current time T _n. Is required. The target weight calculation unit 5 integrates the set target flow rate value G _r to obtain the target integrated weight ∫G _{r of the} raw material that must be delivered by the current time T _n . Subtractor 6
Then, the deviation (∫G _r −G _Tn ) is obtained. The PI control unit 7
The intensity of the vibration generated by the vibration exciter 2b is controlled so that the deviation calculated by the subtractor 6 approaches zero.
The comparator 9 detects that the weight value G _S is between the lower limit weight value G _L and the upper limit weight value G _H , and supplies the raw material replenishment period designation signal A to the switching unit 10 and the memory 11. The switching unit 10 outputs the output signal of the PI control unit 7 until the specified signal A is detected.
When the specified signal A is detected, the output signal of the memory 11 is replaced by the output signal of the memory 11 instead of the output signal of the PI control unit 7 until then.
Supply to. The memory 11 reads and outputs the output signal of the PI control unit 7 when the designation signal A is inverted to the raw material replenishment state.

4A to 4C show the weight value G _S , the designation signal A, and the output signal to the vibration exciter 2b. As can be seen from this figure, during the period B until the raw material is replenished in the storage tank 1, the output signal of the PI control unit 7 is variably controlled. If the output signal of the PI control unit 7 immediately before the designated signal A is inverted to the raw material replenishment state is "V3", "V3" is read into the memory 11 and the output of the PI control unit 7 during the raw material replenishment period. Exciter 2b with "V3" read from memory 11 regardless of signal
To continue cutting the raw material by the vibration feeder 2 even during the raw material replenishment period. When the weight value G _S exceeds the upper limit weight value G _H , the vibration exciter 2b is again controlled by the output signal of the PI control unit 7.

In this way, the vibration feeder 2 is set to "V3" during the raw material replenishment period.
Although continuous cutting can be realized by locking and controlling with, the pressure density of the raw material near the raw material inlet of the vibrating feeder 2 is different immediately before the start of raw material replenishment and at the end of raw material replenishment. Has the disadvantage that the flow rate is less than the target value.

5 and 6 show another conventional example which has been improved in consideration of the compaction density of the raw material during filling. Here, components having the same functions as those in FIG. 3 will be described with the same reference numerals.

The control data storage unit 12 outputs the output signals V1 and V2 of the PI control unit 7 when the weight value G _S matches the specified weight values G1 and G2 during the period B.
Is read, and the total weight value G _S is the specified weight value G2 in period C.
When the output signal V2 is read in advance when the
2b is controlled, and the vibrator 2b is controlled by the output signal V1 which is read in advance when the total weight value G _S matches the specified weight value G1.

In this way, the vibrating feeder 2 can be used even during the raw material replenishment period.
You can change the operating state of the
The control cannot be performed when the control data storage unit 12 does not store necessary data. Specifically, the specified weight values G1 and G2
When starting from a state in which the raw material having a weight between 1 and 2 remains in the storage tank 1, the weight value G _S rises to G1 in the period C and there is no data to be read from the control data storage unit 12, so the vibration feeder is used. There is a problem that 2 cannot be controlled.

An object of the present invention is to provide a loss-in-weight type constant flow rate supply device capable of realizing flow rate control of a vibrating feeder in consideration of the pressure density of raw material even when data is not accumulated.

Means for Solving the Problem The loss-in-weight type constant flow rate supply device of the present invention supports a storage tank through a weighing device, and continuously discharges the raw material inside the storage tank by a vibration feeder attached to the storage tank,
The vibration feeder is controlled through a control system so that the decrease in the weight value of the weighing device approaches the target value, and when the raw material in the storage tank is detected to have decreased to the lower limit level, the raw material is replenished to the storage tank. In addition to the above, the increase detection unit detects that the weight value at each moment has increased by the specified weight during replenishment of raw material, and the vibration at the start of replenishment of raw material each time the increase detection unit detects an increase. A calculation unit for increasing the vibration of the feeder by a prescribed amount and a switching unit for supplying the output data of the calculation unit to the vibration feeder during the replenishment of raw materials without depending on the output data of the control system at that time are provided. Is provided.

Operation According to this configuration, the operating state of the vibrating feeder during the supply of raw materials changes according to the weight value at that time. The vibration of the vibration feeder increases as it approaches the end of replenishment.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. It should be noted that components having the same functions as those of FIGS.

FIG. 1 shows a loss-in-weight type constant flow rate supply device of the present invention. Control unit that operates the vibration feeder 2 while replenishing raw materials
13 is configured as follows. The increase detection unit 14 detects that the weight value at each time increases by the specified weight amount ΔG during the replenishment of the raw materials. The calculation unit 15 applies, via the switching unit 10, an output signal, which changes in a direction in which the vibration of the vibration feeder 2 at the time of starting replenishment of raw materials is increased by a specified amount, each time the increase detection unit 14 detects the increase. Output to machine 2b. Memory 16
Is the PI just before the designated signal A is reversed to the raw material replenishment state.
It reads the output signal "V _t" of the control unit 7.

The calculation unit 15 outputs the following signals as the weight value G _S increases and changes. Immediately after the designated signal A is inverted to the raw material replenishment state, the output signal "V _t " is output as in the relationship between the vibration intensity and the output signal of the vibration feeder 2 shown in FIG. 2 (C). After that, the total weight value G _S increases by the specified weight, and “G6” “G5” “G
The increase detection unit 14 supplies a signal to the calculation unit 15 each time the number increases by 4 ", and the output signal changes each time" ΔV "set in the change setting unit 17, resulting in" V _t + ΔV ". "V _t + 2ΔV""V _t +
The vibration of the vibration feeder 2 gradually increases as the supply of raw materials is further increased.

Then, when it is detected from the designation signal A that the period C is inverted to B, the control unit 13 is initialized.

As described above, the output signal of the PI control unit 7 immediately before being inverted in the period C is changed by the change amount set in the change amount setting unit 17 regardless of the data accumulated in the period B immediately before the period C. Since the output signal is an occasional output, even if the output signal of the PI control unit 7 is not collected over the entire range of the period B, the vibration of the vibration feeder 2 is controlled according to the pressure density of the raw material to replenish the raw material. The flow rate can be kept stable.

In the above-described embodiment, when the weight value G _S in the period C exceeds the upper limit weight value G _H , the replenishment of raw materials is completed, and the control signal of the vibration feeder 2 is PI controlled by the switching unit 10 from the output signal of the arithmetic unit 15. Although the output signal of the section 7 is simply switched to, the operation tends to become unstable at the time of shifting from the period C to the period B, so that the raw material replenishment is terminated when the total weight value G _S reaches the upper limit weight value G _H. , The vibration feeder 2 is not immediately returned to the control state by the output signal of the PI control unit 7, but the control state by the output signal of the calculation unit 15 is further extended for a specified time, and after the specified time has elapsed, the vibration feeder is The stability can be improved by returning 2 to the control state by the output signal of the PI control unit 7.

EFFECTS OF THE INVENTION As described above, according to the present invention, an increase detection unit that detects that the weight value at each time increases by the specified weight during replenishment of raw materials, and an increase detection unit detects an increase each time. And a calculation unit that increases the vibration of the vibration feeder at the start of replenishment of raw materials by a specified amount, and during the replenishment of raw materials, the output data of the calculation unit is supplied to the vibration feeder regardless of the output data of the control system at that time. Since the switching unit is provided, the vibration feeder can be operated with the cutout amount according to the pressure density of the raw material even when the raw material is slightly left in the storage tank, and the control accuracy of the flow rate control can be improved. Can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a loss-in-weight type constant flow rate supply device of the present invention, FIG. 2 is a signal waveform diagram of the main part of the device, and FIGS. FIG. 4 and FIG. 6 are schematic diagrams of the conventional constant flow rate supply device, and are waveform diagrams of the main part of the conventional example shown in FIG. 3 and FIG. 5, respectively. 1 ... Storage tank, 2 ... Vibration feeder, 3 ... Weighing device, 7
...... PI control unit, 10 ...... Switching unit, 13 ...... Control unit, 14 ...... Increase detection unit, 15 ...... Calculation unit, 16 ...... Memory, 17 ...... Change setting unit

Claims (1)

[Claims] 1. A storage tank is supported through a weighing device, and a raw material inside the storage tank is continuously discharged by a vibrating feeder attached to the storage tank, and the decrease in the weighing value of the weighing device approaches a target value. By controlling the vibration feeder through the control system as described above, the raw material in the storage tank is detected to have decreased to the lower limit level, and the raw material is replenished to the storage tank.
An increase detection unit that detects that the weight value has increased by a specified amount during raw material replenishment, and a vibration of the vibration feeder at the start of raw material replenishment is specified by the specified amount each time the increase detection unit detects an increase. Loss-in-weight type constant flow rate supply provided with a calculation unit for increasing the value of the calculation unit and a switching unit for supplying the output data of the calculation unit to the vibration feeder regardless of the output data of the control system at that time during the replenishment of raw materials. apparatus.