JPH02132011A - Granular material discharging device - Google Patents

Abstract

PURPOSE:To improve the discharge control precision by selecting the vibration frequency in response to the load change or a feeder based on the measured data of the load and flow speed for each vibration frequency so that the flow speed is made constant in a medicine quantitative discharging device using a vibration feeder. CONSTITUTION:A central processing unit 4 selects the relational data among the vibration frequency, load, and flow speed in response to the type of an inputted bulk material, e.g., D1. The optimum frequency corresponding to the present load is selected from the data D1 based on the load signal SL outputted from a weight measuring device 3, and the AC power source corresponding to the frequency signal is fed to an electromagnetic section 10 via a D/A converting circuit 6, an integrating circuit 7, a V/F converting circuit 8, and a power driving circuit 9. A vibration feeder 2 is operated at the preset frequency, and the flow speed is made nearly constant. The discharge control precision can be improved according to this constitution.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a powder discharge device using a vibrating feeder,
In particular, the present invention relates to a powder discharge device having a control device that can accurately control the discharge of powder and granules.

[Conventional technology]

For example, discharge (cut out) a certain amount of chemicals, pigments, etc.
In some cases, very precise cutting is required to the milligram level. In response to such demands, devices are in use that combine a load measuring device such as an electronic balance that can accurately measure loads with a vibrating feeder as a device for discharging powder and granular material. This device stops the vibrating feeder when the weight of the powder filled in the vibrating feeder drops to a preset discharge amount, and repeats this process to discharge each predetermined amount. It is designed to be cut out.

[Problem to be solved by the invention]

FIGS. 4 and 5 show the relationship between the amount of powder discharged in a vibrating feeder with a constant vibration frequency and the weight of powder filled in the vibrating feeder (hereinafter referred to as "load"). As is clear from this figure, when the frequency is kept constant, the amount of powder discharged per unit time (hereinafter referred to as "flow velocity") is small when the load on the vibrating feeder is large, but the discharge progresses. The flow rate increases rapidly as the load decreases.

For this reason,. When the load is large, relatively accurate cutting is possible by turning the vibrating feeder on and off, but when the load is small, the on/off control of the vibratory feeder cannot cope with the increased flow velocity, resulting in inaccurate cutting. turn into.

FIG. 5 shows the above state in terms of the relationship between flow velocity and time.

At first, the flow velocity increases relatively slowly because the load is large, but when the load decreases to a certain extent, the flow velocity increases dramatically. However, when the amount of powder and granules filled in the vibrating feeder falls below a certain amount, the flow rate will decrease rapidly.
This is the second cause of deterioration in cutting accuracy. Note that the reason why the flow rate suddenly decreases after increasing is that the fluidization of the entire powder and granule is maintained due to the vibration interaction of the powder and granule particles, which maintains a high flow rate. On the other hand, when the remaining amount decreases, such interaction between particles disappears, and the fluidity of the powder as a whole decreases, which is considered to be a major cause.

In any case, the large change in the flow velocity of the powder during the cutting process is a major obstacle to improving cutting accuracy. For this reason, a control method has been proposed in which the vibration frequency of the vibration feeder is controlled to prevent sudden changes in the flow velocity of the powder or granular material, but the frequency adjustment largely depends on the operator's discretion. The reality is that control is inaccurate and the desired effects cannot be achieved.

[Means for Solving the Problems] The present invention was constructed in view of the above technical problems, and the present invention accumulates as data the relationship between the load and flow velocity for each vibration frequency in a vibration feeder, and This is a control device that sequentially adjusts the frequency based on this data in response to changes (decrease) in load so as to maintain the flow velocity. Furthermore, by storing the relationship between the load and the flow velocity for each different vibration frequency for each type of powder or granule, it is possible to handle a plurality of types of powder or granule.

C action] By sequentially plotting the changing load and the frequency corresponding to the preset flow velocity at this changed load, setting the adjustment frequency, and controlling the vibration feeder based on this adjustment frequency, the powder in the vibration feeder can be controlled. The flow rate of the particles is kept almost constant and the particles are sequentially cut out in this state.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows the overall configuration of the powder discharge device, and FIG. 2 shows the relationship between the load and flow velocity at the vibration frequency of the vibrating feeder.

First, the control concept in this device will be explained with reference to FIG.

Each diagram in the figure shows the relationship between the load at each frequency '(l) to '(5) and the flow rate (mg/sec) which is the powder discharge rate from the vibratory feeder. Note that the relationship between frequency and flow velocity is such that below a certain frequency, the flow velocity increases as the frequency increases, but when the frequency is higher than that, the flow velocity decreases by increasing the frequency. The present invention is configured to perform control using a high frequency range in which the flow velocity decreases as the frequency increases.

First, a vibrating feeder is filled with granular material, its load is set to L1, and the flow rate to be kept constant regardless of a decrease in the load is set to Q (mg/sec). In this state, the frequency required to achieve the flow velocity Q is f(1), as is clear from the figure. However, if the load decreases as the granules are discharged, the frequency f(1) will become higher than the set flow rate Q. Therefore, in the load L2, the higher frequency r(2) is used to maintain the flow velocity at a value substantially close to the set flow velocity Q. In addition, from frequency f(1) to [ku2)
The frequency f (1) is used during the time when the flow rate changes to Q, and therefore, cutting is performed on the assumption that the flow rate gradually becomes higher than the set flow rate Q. Subsequently, when the load becomes L2, the frequency is set to higher f(2), the flow velocity is lowered, and the flow velocity is adjusted to the set flow velocity Q again. In this way, the loads L3, L4, L
5 and gradually decrease the frequency to a higher frequency f(
3) By switching to , r(4>, f(5)), it is possible to maintain the flow velocity at Q or a value close to this even if a change (decrease) in load occurs.

In this way, it is possible to maintain the flow velocity almost constant, so it is possible to precisely control the vibrating feeder, and high cutting accuracy can always be achieved regardless of the magnitude of the load L.

FIG. 3 shows the relationship between flow velocity and time in a state where the flow velocity is controlled by gradually adjusting the frequency in this manner. The flow velocity fluctuates up and down as time passes by switching to each vibration frequency, but this fluctuation is within the range (indicated by diagonal lines in the figure) in which the cutting amount can be precisely controlled, so there is no problem at all. The powder to be cut out is ceramic particles with a particle size of 1m+n to several tens of microns, and the set flow rate Q is 500μ/s.
ec, the load L1 when filling the vibration feeder is approximately 20
Assuming 0g, the frequency f(1) is approximately 9 7 Hz,
It has been experimentally determined that approximately 98 Hz is appropriate for f(2).

Note that the relationship between load and flow velocity in each frequency range shown in Figure 2 differs depending on the type of powder or granule, so the relationship between load and flow velocity can be determined by changing the frequency for each powder or granule. Investigate the relationship and manually store this data in the memory circuit of the control device.

Next, a configuration example of a control device configured based on the control concept described above will be explained using FIG. 1.

In the figure, reference numeral 1 indicates a control device, arrow 2 indicates a vibratory feeder controlled by this control device, and 3 indicates a weight measuring device for measuring the weight of powder and granular material discharged from the vibratory feeder. In the control device 1, 4 is a central processing unit, and 5 is a data base in which the relationship between the load at each vibration frequency and the powder flow velocity is input, and data is stored for each type of powder such as D1, D2, etc. The collected data has been entered. 6 is a D/A conversion circuit that converts the digital signal output from the central processing unit into analog; 7 is an integration circuit; 8 is a circuit that converts the output signal into a frequency; 9 is a power supply to the electromagnetic section 10 of the vibration feeder 2; A power supply circuit l1 is an I/O port for inputting a weight signal output from the weight measuring device 3 to the central processing unit 4.

In the apparatus having the above configuration, first, the vibrating feeder 20 hopper 2a is filled with powder to be cut out, and the type of the powder is input manually to the central processing unit 4 of the control device 1. The central processing unit 4 selects data corresponding to the type of powder or granular material, for example, DI, and controls the frequency based on the data to maintain the flow velocity of the powder or granular material approximately constant. More specifically, the optimal frequency corresponding to the current load is determined from the data D using the load signal SL output from the weight measuring device 3.
Select from I. The frequency signal is transmitted to the D/A conversion circuit 6,
It is supplied as an AC power source having a frequency corresponding to the frequency signal through an integrating circuit 7, a V/F conversion circuit 8, and a power supply driving circuit 9, and controls the vibrating feeder 2 to operate at a predetermined frequency.

In this way, by gradually adjusting the vibration frequency based on the data DI, the flow velocity of the powder or granular material is kept almost constant regardless of changes in the load L of the vibration feeder. In this state, a predetermined amount of cutting is performed one after another.

〔effect〕

As the configuration of the present invention has been specifically explained above, the relationship between the load and flow velocity for each different vibration frequency in a vibratory feeder is accumulated as data, and changes in the load (reduction) are performed to maintain a constant flow velocity. ), the frequency is sequentially adjusted based on this data, making it possible to perform cutting at a nearly constant flow velocity regardless of changes in the load on the vibratory feeder, improving cutting accuracy. can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a control system diagram of the powder discharge device of the present invention, Fig. 2 is a diagram showing the relationship between load and powder flow velocity for each vibration frequency, showing the control concept of the present invention, and Fig. 3 is A diagram showing the relationship between the flow velocity of powder and granular material and time in the device of the present invention, Fig. 4 is a diagram showing the relation between load and flow velocity when the frequency is constant, and Fig. 5 is a diagram showing the relationship between the powder and granular material flow velocity when the frequency is constant. It is a diagram showing the relationship between particle flow velocity and time. 1...Control device 2...Vibration feeder 3...Load measuring device 4...Central processing unit 5...Database DI, D2...Data for each powder type Fig. 2 Fig. 3 Ginkai (T) Figure 1 Figure 5 (T)

Claims (2)

[Claims] (1) A data section that inputs data measuring the relationship between load and flow velocity for each vibration frequency, and a processing section that selects a predetermined vibration frequency in response to changes in the load of the vibration feeder based on the data in this data section. By gradually selecting the vibration frequency corresponding to the set flow velocity at each load,
1. A powder discharge device characterized in that the flow velocity of the powder is always maintained substantially constant regardless of changes in the load of a vibrating feeder. (2) A patent claim characterized in that the data section is configured to store the relationship between load and flow velocity for each vibration frequency for each type of powder or granule, and to be able to handle multiple types of powder or granule. The powder discharge device according to the scope item (1).