JPH0325321A - Loss-in-weight type constant flow-rate supplier - Google Patents

Abstract

PURPOSE:To improve control accuracy by providing an increase detection part which detects a weighed value increasing by prescribed weight, and an arithmetic part which increases the vibration of a vibration feeder by a prescribed quantity every time the increase detection part detects the increase. CONSTITUTION:The increase detection part 14 detects the current weighed value increasing by the prescribed weight G during raw material supplementation. The arithmetic part 15 outputs an output signal which varies the vibration of a vibration feeder 2 by the prescribed quantity at the time of starting the raw material supplementation to an exciting machine 2b through a switching part 10 every time the increase detection part 14 detects the increase. Then the output signal of a PI control part 7 right before it is inverted in a period C is given variation set in a variation setting part 17 irrelevantly to the data stored in a period right before the period C to obtain the current signal, so the flow rate during the raw material supplementation can be held stable by controlling the vibration of the vibration feeder 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a loss-in-weight type device among constant flow dispensing devices for dispensing raw materials at a constant flow rate from a storage tank.

2. Description of the Related Art This type of loss-in-weight constant flow rate supply device is constructed as shown in FIG. 3 or FIG. 5.

The apparatus shown in FIG. 3 is constructed as follows. A vibrating feeder 2 consisting of a trough 2a and a vibrator 2b is attached to the bottom of the storage tank 1, and these are installed on a tray of a weighing device 3.

The occasional net weighing value Gs of the weighing device is input to the payout calculation section 4. Here, the reduced weight ΔG of the weighed value Gs per unit time is repeatedly calculated and integrated, and the cumulative weight G1 of the raw material actually delivered through the vibrating feeder 2 up to the current time T1 is calculated. It is being The target weight calculating section 5 integrates the set target flow rate value G1 to obtain the deviation (.fG, -Ga.) at the current time T. The PI control unit 7 controls the intensity of the vibration generated by the vibrator 2b so that the deviation calculated by the subtractor 6 approaches zero. The comparator 9 detects that the weight value Gs is between the lower limit weight value GL and the upper limit weight value G4, and supplies a raw material replenishment period designation signal A to the switching unit 10 and the memory H. The switching unit 10 supplies the output signal of the PI control unit 7 to the vibrator 2b until the specified signal A is detected, and when the specified signal A is detected, the switching unit 10 supplies the output signal of the PI control unit 7 to the vibrator 2b in place of the previous output signal of the PI control unit 7. The output signal of the memo Ull is supplied to the vibrator 2b. The memory 11 reads and outputs the output signal of the PI control section 7 when the designation signal A is inverted to the raw material replenishment state.

Figures 4(a) to (C) show weight values G. shows the designated signal A and the output signal to the vibrator 2b. As can be seen from this figure, during the period B until the storage tank 1 is replenished with the raw material, the control is variably controlled by the output signal of the PI control section 7 at each time. Assuming that the output signal of the PI control unit 7 immediately before the designation signal A is inverted to the raw material replenishment state is "v3", the memory 11
During the raw material replenishment period, the vibrator 2b is operated with "v3" read from the memory 11 regardless of the output signal of the PI control unit 7, and the vibration feeder 2 is operated during the raw material replenishment period. Continue cutting out raw materials. When the weighed value G1 exceeds the upper limit weight value GH, the vibrator 2b is activated again to PI.
It is controlled by the output signal of the control section 7.

During the raw material replenishment period, the vibration feeder 2 is set to “v3”.
Continuous cutting can be achieved by locking and controlling with has the disadvantage that the flow rate is less than the target value.

FIGS. 5 and 8 show another conventional example which has been improved by taking into account the degree of compaction of the raw material during filling. Components having the same functions as those in FIG. 3 will be described with the same reference numerals.

The control data storage unit l2 determines that during period B, the weight value G1 is equal to the specified weight value Gl. The output signals Vl and V2 of the PI control unit 7 when they match G2 are read, and the weighted value G is determined in period C.
．． When the weighed value G3 matches the specified weight value G2, the vibrator 2b is controlled by the preloaded output signal v2, and when the weighed value G3 matches the specified weight value G1, the preloaded output signal ■1 controls the vibrator 2b. 2b.

Problem to be Solved by the Invention In this way, the operating state of the vibrating feeder 2 can be varied even during the raw material replenishment period, and accuracy can be improved. In such cases, it cannot be controlled. Specifically, when starting from a state in which raw materials weighing between the specified weight values G1 and 62 remain in the storage tank 1, the weighed value Gs rises to G1 during the period C and the control data storage section l2 There is a problem in that the vibrating feeder 2 cannot be controlled because there is no data to be read from the vibrating feeder 2.

SUMMARY OF THE INVENTION An object of the present invention is to provide a loss-in-weight constant flow rate supply device that can realize flow rate control of a vibratory feeder in consideration of the compaction density of raw materials even when no data is accumulated.

Means for Solving the Problems The loss-in-weight constant flow supply device of the present invention supports a storage tank via a weighing device, continuously dispenses the raw material inside the storage tank by a vibrating feeder attached to the storage tank, and The vibration feeder is controlled via the control system so that the decrease in the weight value of the weighing device approaches the target value, and when it is detected that the raw material in the storage tank has decreased to the lower limit level, the raw material is replenished into the storage tank. In addition, there is an increase detection section that detects that the weight value at each time increases by a specified weight during replenishment of raw materials, and a vibration feeder that detects when the increase detection section detects that the weight value has increased by a specified amount. and a switching unit that supplies the output data of the calculation unit to the vibration feeder without depending on the output data of the control system at that time during replenishment of raw materials. It is characterized by having been established.

Effect: According to this configuration, the operating state of the vibratory feeder during material replenishment changes depending on the weight value at that time.

The vibration of the vibrating feeder increases as the end of replenishment approaches.

EXAMPLE Hereinafter, an example of the present invention will be explained based on FIGS. 1 and 2. Components having the same functions as those shown in FIGS. 3 to 6 showing the conventional example will be described with the same reference numerals.

FIG. 1 shows a loss-in-weight constant flow supply device of the present invention. Control unit l that operates the vibrating feeder 2 during raw material replenishment
3 is configured as follows.

The increase detection section 14 detects that the weight value at each time increases by a specified weight amount ΔG during replenishment of raw materials. The calculation unit 15 applies an output signal that changes in a direction to increase the vibration of the vibrating feeder 2 by a specified amount at the start of raw material replenishment every time the increase detection unit l4 detects an increase, via the switching unit 10. Output to machine 2b. The memory lJlG reads the output signal "Vt" I of the PI control section 7 immediately before the designation signal A is inverted to the raw material replenishment state.

The calculation unit 15 outputs the following signal as the weight value G1 increases. Immediately after the designation signal A is reversed to the raw material replenishment state, an output signal "Vt" is outputted as shown in the relationship between the vibration intensity of the vibrating feeder 2 and the output signal shown in FIG. 2(C). After that, the weight value G. increases by the specified weight and becomes “G6”
65''"G4" Each time it increases, the increase detection section l4 supplies a signal to the calculation section l5, and the output signal changes each time by "ΔV" set in the change setting section l7. Then, “Vt+ΔV”Vt+2ΔV”■,+3ΔV”...
..., and the vibration of the vibrating feeder 2 becomes stronger little by little as the replenishment of raw materials progresses.

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

In this way, the output signal of the PI control section 7 immediately before being inverted in the period C is changed by the amount of change set in the change amount setting section l7, regardless of the data accumulated in the period B immediately before the period C. Since the output signal is output from time to time, even if the output signal of the PI control unit 7 is not collected over the entire range of period B, the vibration of the vibrating feeder 2 is controlled according to the degree of consolidation of the raw material, and the replenishment of the raw material is performed. can maintain a stable flow rate.

In the above embodiment, when the weight value G in the period C exceeds the upper limit weight value Gu, the replenishment of the raw material is terminated, and the control signal for the vibration feeder 2 is changed to the calculation unit l5 by the switching unit 10.
The output signal was simply switched from the output signal of the PI controller 7 to the output signal of the PI control unit 7, but since the operation tends to become unstable when transitioning from period C to period B, when the weighed value Gs becomes less than the upper limit weight value Gt, Finish replenishing the raw material and immediately turn the vibrating feeder 2 to P.
Without returning to the control state based on the output signal of the I' control unit 7, the control state based on 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 2 is controlled by the PI control unit. The stability can be improved by returning to the control state by the output signal of No. 7.

Effects of the Invention As described above, according to the present invention, there is an increase detection section that detects that the weight value at each time increases by a specified weight during replenishment of raw materials, and an increase detection section that detects that the weight value increases by a specified weight at each time during replenishment of raw materials. a calculation unit that increases the vibration of the vibration feeder by a predetermined amount at the time of starting replenishment of raw materials; and during replenishment of raw materials, output data of the calculation unit is supplied to the vibration feeder without depending on the output data of the control system at that time. Even when starting with a small amount of raw material remaining in the storage tank, the vibration feeder can be operated with the amount of cutout according to the degree of consolidation of the raw material, improving control accuracy of flow rate control. can be improved.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the loss-in weight type constant flow supply device of the present invention, Fig. 2 is a signal waveform diagram of the main part of the same device, and Figs. 3 and 5 are the conventional loss-in weight type constant flow supply device. 4 and 6 are waveform diagrams of essential parts of the conventional example shown in FIGS. 3 and 5, respectively. DESCRIPTION OF SYMBOLS 1... Storage tank, 2... Vibration feeder, 3... Weighing device, 7... PI control part, 1O... Switching part, 13...
・Control unit! 4... Increase detection section, 15... Calculation section,
IG...Memo IJ, 17...Change setting section. Figure tFigure 8Figure 2Figure 4Figure SFigure B

Claims (1)

[Claims] 1. The storage tank is supported via a weighing device, and the raw material inside the storage tank is continuously discharged by a vibrating feeder attached to the storage tank, and controlled so that the decrease in the weight value of the weighing device approaches the target value. controlling the vibratory feeder via a system;
an increase detection section configured to detect that the raw material in the storage tank has decreased to a lower limit level and replenish the raw material to the storage tank, and to detect that the weight value at each time increases by a specified weight while replenishing the raw material; and a calculation unit that increases the vibration of the vibration feeder at the start of raw material replenishment by a specified amount each time the increase detection unit detects an increase, and during raw material replenishment, output data of the control system at that time is sent to the vibration feeder. a loss-in-weight type constant flow supply device, comprising a switching section that supplies output data of the arithmetic section without depending on the output data of the arithmetic section.