JPH034091B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a weighing method using a plurality of loss-in-weight type feeders.

For example, when blending raw materials A and B, 2
Two loss-in-weight constant feeders are used, but in the conventional weighing method, no weighing signals are exchanged between the two feeders. In other words, when mixing A raw material and B raw material at a ratio of 1:2, conventionally, the flow rate per unit time is set to Fo in the first feeder that handles A raw material, and B
The second feeder that handles raw materials is set at 2.Fo as the flow rate per unit time, and the first and second feeders individually control the flow rates to reach the target flow rates of Fo and 2.Fo while feeding raw material A and raw material. is cut out.

However, with such a mixing method, no problems will occur if both the first and second feeders are operated correctly, but if the operation of one of the feeders is disturbed, the above-mentioned 1:2 mixing ratio will be disrupted. This has the disadvantage that a stable amount cannot be obtained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a blending method using a loss-in-weight type feeder that is capable of blending at a stable ratio over a long period of time.

The mixing method using the loss-in-weight type feeder of the present invention is such that when raw materials are simultaneously cut out and proportioned by the loss-in-weight type feeder with a double feeder, the master feeder among the plurality of units performs cutting by controlling the set flow rate. The target flow rate of the slave feeder is changed according to the actual flow rate of the master feeder, and the average control voltage of the slave feeder before the material replenishment is changed during the material replenishment to the slave feeder. The feature is that cutting is continued while being corrected by the flow rate change rate of the master feeder.

Hereinafter, specific embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an apparatus for mixing and weighing raw materials A and B. 1 is the raw material cutting shelf, A raw material container 2
1st and 2nd to measure the weight of A and B raw material containers 2B
Weighing machines 3A and 3B are provided. Note that the first and second weighing machines 3a and 3B are provided with discharge passages 4 on their upper surfaces corresponding to the discharge ports of the raw material containers 2A and 2B, respectively. 5A and 5B are feeders that are supported from the top surface of 3A and 3B by the first and second weighing machines, respectively, and the raw material receiving ports are the first and second weighing machines, respectively.
It communicates with the respective discharge passages 4 of the second weighing machines 3A and 3B. 6 is a filling machine that receives and dispenses raw materials A and B from feeders 5A and 5B; 7A is a master control device that controls the feeder 5A based on changes in the measured value W _A of the first weighing machine 3A; 7B is a slave control device that controls the feeder 5B based on changes in the measured weight W _B of the second weighing machine 3B.

Here, the configurations of the master control device 7A and the slave control device 7B will be explained together with their operations, taking as an example a case where raw materials A and B are mixed and measured at a ratio of 1:2.

In the master control device 7A, the target flow rate Fo per unit time is set in the comparator 8 as shown in FIG _. W _K+N , the sampling interval of the weight value from the first weighing machine 3A is N [seconds], N [seconds]
When _the weight value W _{A of} the first weighing machine 3A _in front of
−W _K+N )/N and the comparator 8
is compared with the target flow rate Fo. The flow rate error detected by the comparator 8 is input to the rotation speed determining means 10, and the feeder 5 necessary to bring this flow rate error close to zero is inputted to the rotation speed determining means 10.
The rotation speed of A is determined, and a control voltage V _M corresponding to the determined rotation speed is output. This control voltage V _M serves as an input signal to the power variable control section 12 that executes power control to the drive motor 11 of the feeder 5A. In this way, the rotation speed of the feeder 5A is controlled so that the actual flow rate of the feeder 5A matches the target flow rate Fo.

On the other hand, the slave control device 7B has a mixing ratio α
= 2 and the latest instantaneous flow rate Ft calculated by the master control device 7 are input, and the discharge cumulative target weight calculation unit 13 calculates the current value from the start of cutting by calculating ∫ ^t _p (F _t・α) dt. feeder 5B until time t of
Calculate the cumulative discharge target weight W _Bp by
Then, the actual discharge cumulative target weight W Bt of the B raw material determined from the weight value W _B of the second weighing machine _3B (weight of the raw material cut out from the second weighing machine 3B from the start of cutting to the current time t) is compared with the discharge cumulative target weight W _Bp , and the drive motor 17 of the feeder 5B is further controlled via the rotation speed determining means 15 and the power variable control unit 16 so that the discharge cumulative target weight W _Bt approaches W _Bp .

Note that during the period of replenishing raw materials to the feeder 5B, the actual cumulative discharge weight W _Bt cannot be calculated from the measured weight W _B , so continuous cutting is achieved by the following processing.

First, the fluctuation calculation unit 18 calculates the fluctuation rate β of the actual flow rate of the feeder 5A at time t by comparing it with the past flow rate, and calculates the fluctuation rate β of the actual flow rate of the feeder 5A at the time t, and calculates the rate of fluctuation β of the actual flow rate of the feeder 5A at the time t, and calculates the fluctuation rate β of the actual flow rate of the feeder 5A at the time t, and calculates the fluctuation rate β of the actual flow rate of the feeder 5A at the time t, and calculates the fluctuation rate β of the actual flow rate of the feeder 5A at time t, The average calculation unit 19 calculates the average from the end of replenishment to just before the start of the current raw material replenishment, and the calculated average control voltage
The multiplier 20 multiplies V _SA by the flow rate fluctuation rate β of the feeder 5A to correct it, and when replenishing raw materials to the feeder 5B, the switch 21 is connected to the multiplier 20 side and the power variable control unit 16 (V _SA・Controlled by β). Switch 21 is activated after the weight value W _B has stabilized.
Returned to Vs side.

Furthermore, in the above embodiment, a case has been explained in which the instantaneous flow rate Ft is calculated to control the feeder 5B on the slave side, but this is calculated from the average flow rate F _A determined by the moving average of the instantaneous flow rate Ft to ∫ ^t _p (F _A The same effect can be obtained even if the feeder 5B is controlled by calculating the cumulative discharge target flow rate of the B raw material using α) dt.

In the above embodiment, the instantaneous flow rate F _t or average flow rate F _A calculated by the master control device 7A is integrated by the slave control device 7B to calculate the cumulative target weight of B raw material discharged.
Since feeder 5B is controlled to obtain W _Bp ,
Once the control of feeder 5A is disrupted, feeder 5A
The feeder 5B will not return to a stable state until a considerable amount of time has passed after the control of the feeder 5B returns to a stable state.
However, this problem occurs when the weight value of the first weighing machine 3A is sent from the master control device 7A to the slave control device 7B.
Actual cumulative discharge weight of raw material A determined from W _A W _Ap
and in the slave control device 7B, (W _Ap・α)
By controlling the feeder 5B so that W _Bp approaches W Bp, stable ratio control of the feeder 5B can be realized. In this case, the specific calculation of the flow rate fluctuation rate β is performed as follows.

As shown in FIG. 3, the supply of raw materials to the feeder 5B is started from time t ₀ , and the cumulative weight discharged from the feeder 5A from time t ₀ to t _k is determined as W ₁₀ , W ₁₁ , W ₁₂ ,
When W _1k , at time t ₀ to t ₁ , the above V _SA
From time t ₁ to _{t 2} , W ₁₁ −W ₁₀ /(W ₁₀ /t ₀ )・T
The control voltage is the V _SA corrected by = β, and the time t ₂ to _{t 3}
is W ₁₂ −W ₁₁ /(W ₁₀ /t ₀ )・T=β, or W ₁₂ −W ₁₀ /W
The control voltage is created by correcting V _SA by ₁₀ /t ₀ · 2T = β. Below, β is calculated from time to time in the same way, and V _SA
is corrected.

As explained above, according to the weight distribution method using the loss-in-weight type feeder of the present invention, the slave feeder is controlled according to the actual cumulative discharge weight of the master feeder, so even if the flow rate of the master feeder is disturbed, the slave feeder is The flow rate changes accordingly, allowing a stable ratio of blending to be achieved. Furthermore, in the present invention, even while the raw material is being supplied to the slave feeder, the amount of raw material to be cut out can be controlled in accordance with changes in the flow rate of the master feeder, so that a stable blend can be achieved over a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing a specific embodiment of the mixing method of the present invention and a configuration diagram of the control device, FIG. 2 is a configuration diagram of the control device immediately after startup, and FIG.
The figure is an explanatory diagram during the slave feeder material replenishment. 2A...A raw material container, 2B...B raw material container, 3A...first weighing machine, 3B...second weighing machine, 5A, 5B...feeder, 7A...master control device, 7B...slave Control device, F _p ...
Target flow rate, F _t ... Instantaneous flow rate, α ... Mixing ratio.

Claims (1)

[Claims] 1 When raw materials are simultaneously cut out and proportioned using a plurality of loss-in weight type feeders, the master feeder among the plurality of units executes cutting by controlling the set flow rate, and the target flow rate of the slave feeder is adjusted to the target flow rate of the master feeder. The loss is changed according to the actual flow rate, and during material replenishment to the slave feeder, the average control voltage of the slave feeder before material replenishment is corrected by the flow rate change rate of the master feeder during material replenishment while cutting continues. A method of distributing amounts using an in-weight feeder.