JPS6179120A - Device for supplying fixed quantity - Google Patents

Abstract

PURPOSE:To improve precision of the flow rate control by providing a measuring tank to the lower part of a storage tank provided with a device supplying and discharging goods and calculating the discharge flow rate with a calculating means and controlling the discharge flow rate with a controlling means based on the discharge flow rate and the reference flow rate. CONSTITUTION:When the goods are supplied into the storage tank 2 by a supply feeder 4 and weight attains a ceiling value, the supply is stopped and a supply feeder 6 is operated to supply the goods into the measuring tank 8. Then, when the weight attains the ceiling value, the supply feeders 4, 6 are stopped and a discharge feeder 10 is operated to discharge the goods from the measuring tank 8. Then, a measuring signal of a measuring instrument 11 is used to calculate the flow rate of the discharge feeder 10 by a calculator 20 and based on this calculation, the quantity of the discharge feeder 10 is controlled by a controller 14 and a feeder controller 16. Hereby, since the flow rate or the discharge feeder 10 can be calculated while the goods are supplied from the storage tank 2 to the measuring tank 8, the flow rate can be controlled with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a quantitative feeding device for feeding articles such as lumps, powders, granules, or liquids at a constant flow rate.

<Prior Art> Conventionally, the above-mentioned fixed-quantity feeding apparatus has been shown in FIG. 3. In the figure, 2 is a storage tank, into which goods are supplied by a supply feeder 4. The articles in the storage tank 2 are supplied by a supply feeder 6 to a measuring tank 8 provided below the storage tank 2 up to an upper limit (WE). After this supply is completed, the supply feeder 6 is stopped, and the article is discharged from the weighing tank 8 by the discharge feeder 10. At this time, the calculator 12 calculates the flow rate based on the change in the metering signal from the metering device 11 provided in the metering tank 8 . This flow rate is compared with the set flow rate in the controller 14, and both
” is multiplied by appropriate proportional (P) and integral (I) constants. This multiplied value is calculated by the feeder controller 16.
The controller 16 controls the feeder 1o to control the flow rate of the articles discharged from the measuring tank 8 to a constant value. Such control is based on the weight 11 of the articles in the weighing tank 8.
This process is continued until 1M reaches the lower limit value (Wr, ). When the weight WM reaches the lower limit value WL, the feeder controller 16
The supply feeder 6
Accordingly, the weight WM from the storage tank 2 to the measuring tank 8 reaches the upper limit value WH.
supply goods until When the weight WM reaches the upper limit value 1H, the supply feeder 6 is cleaned up, and the flow rate of the articles supplied from the measuring tank 10 is controlled to be constant again in the same manner as described above. This is repeated sequentially.

<Problems to be Solved by the Invention> In the above-mentioned quantitative feeding device, the weight vl of the article in the measuring tank 8
While the goods are being supplied from the storage tank 2 to the measuring tank 8 so that IM becomes the lower limit value W+- and the weight WM becomes the upper limit value WH, the flow rate control is not performed and the flow rate control accuracy deteriorates. there were. This problem is caused by the fact that the weighing device IO cannot accurately measure the weight WM due to the impact force generated when the article falls from the supply feeder 6 while the article is being supplied from the supply feeder 6 to the weighing tank.

Means for Solving the Problems> The solution to the above problems is to add a metering device to the storage tank in the conventional metering device described above.
Based on the measurement signal from this weighing device, the measurement signal from the weighing device of the weighing tank, and the falling height of the product supplied from the storage tank, the weight WM of the product in the weighing tank that has reached the lower limit value WL
The computing unit is provided with a function of computing the flow rate of the article being supplied from the measuring tank until it reaches the upper limit value W■.

According to the above means, since the arithmetic unit is provided with the above-mentioned functions, the weight of the article in the weighing tank reaches the lower limit value 'RL and reaches the upper limit value WH again. The flow rate can also be calculated, and the flow rate of the article supplied from the metering tank can be controlled based on this flow rate and the set flow rate.

Embodiment Example This embodiment, as shown in FIG. 1, has almost the same structure as the conventional one shown in FIG. , is different from the conventional one in that the configuration of the arithmetic unit 20 is different.

When the supply feeder 6 is stopped, the computing unit 20 determines the flow rate of the articles being discharged from the discharge feeder 10 based on the weighing signal W1 of the weighing device 11, that is, a signal corresponding to the article weight WM in the weighing tank 8. It is configured to calculate Q5+. That is, the arithmetic unit 20 converts Q51 into q s + = d w/ .
...(1) Calculate by dt. This is the same function as the conventional arithmetic unit 12 shown in FIG.

Further, when the supply feeder 6 is operated, the computing unit 20 calculates the flow rate Q52 of the article being supplied from the supply feeder 10 based on the measurement signal W of the measurement device 11 and the measurement signal W8 of the measurement device 18. is configured to perform calculations. That is, the computing unit 20 computes Q32 as follows. However, H is the falling height g of the article and is the gravitational acceleration. The reason why the flow rate Q52 is determined by equation (2) will be explained below.

When the supply feeder 6 is in operation, the force acting on the weighing tank 8, that is, the weighing signal W of the weighing device 11, is as follows: W=WM+Fs...River...River...
- (Represented by 31. Fs is the impact force generated when the article falls from the supply feeder 6° into the weighing tank 8. This impact force FB is expressed as follows, where O is the initial falling speed of the article. However, Q2 is the flow rate of the article supplied from the supply feeder 6. Also, Q2 is Q2/'tit...
・・・・・・・・・・River・・・(51, so F
s is (41, (based on formula 51). Also, the weight change dwM/d of the article in the weighing tank 8 is /d, = qs2・Q2...
It is expressed as (7). Therefore, Q52 is (51, (71
Expression si”””dt” dτ・・・・・・・・・
・Hit: Self: +81. Therefore, Q32 is +8h
(From formula 91, Q32=dvl/dt-pressure Xcur1.;
+dZ and f), the flow rate Q52 can be calculated from equation C2).

In addition, in formula (2), it is necessary to measure the falling height H of the article, but this can be measured, for example, by providing a level meter or a phototube in the measuring device N8. Further, by utilizing the fact that there is a correlation between W and H, it is possible to know H without using a level meter or the like. In other words, if W is large, it means that many articles are stored in the weighing tank 8.
This means that H is small. Conversely, if W is small, it means that a small number of articles are accommodated in the weighing tank 8, which means that H is large. Therefore, the weighing signals of the weighing device 18 from the time when the number of articles IIIL is stored in the weighing tank 8 until the time when the number of articles WH is stored in the weighing tank 8 are measured in advance for an appropriate number of articles, and the falling height of the articles corresponding to each of these is measured in advance. (2) The flow rate Q32 can be calculated by substituting it into the equation. However, in this case, the calculation of the flow rate Q52 becomes intermittent.

Note that the flow rate Q2 of the supply feeder 6 is the same as that of the supply feeder 10.
must be larger than the maximum flow rate Q5max. Otherwise, the metering tank 8 will be empty quickly. Also, the capacity C of storage M2 is C= (wFl・WL) Q2/ (Q2・q!ma
x)...Must be 101 or more. That is, the time T2 during which the supply feeder 6 operates is 1. 2=(WtWL)/(Q2・Q5.,ax)・Misaki...
It is expressed as sleep (II). Therefore, even if the supply feeder 6 operates for 72 hours at least at the flow rate Q2, the storage tank 2
Since it is necessary to be able to supply goods to the supply feeder 6, its capacity C is: C=Q2 T2 = (WH-Wb) Q2/(Q2-
Q5rnax) or higher. Moreover, the flow rate Q1 of the supply feeder 4 is as follows: 1 :Q2・Qsmax/(Q2・qsmax)・
(It must be 12 or more. In other words, 3 is the time required for the article in the weighing tank 8 to change from WH to WL.
s = (WH・WII)/Q3max・・・・・・・・・
・Represented by 0 (branch). Therefore, the flow rate Q1 of the supply feeder 4 is =Q2·Q3max/(Q2−Q5max).

In the quantitative feeding apparatus configured as described above, first, the supply feeder 4 supplies the article to the storage tank 2, and when the weight reaches the upper limit value WsH, the supply feeder 4 is stopped. Then, the supply feeder 6 is operated to co-feed the articles to the weighing tank 8, and when the weight reaches WH, the feeder 6 is operated to start discharging the articles from the weighing tank 8.

At this time, using the measurement signal of the measurement device 11, the calculation unit 2
At 0, the flow rate of discharge feeder 0 is Q! using the 0+ formula. +
Calculate. Based on this flow rate q3j, the discharge feeder 10 is controlled by the controller 14 and the feeder controller 16.
Flow rate Q31 is controlled.

During this control, when the weight of the stored N2 becomes less than WsH, the supply feeder 4 is operated and the article is placed in the storage tank 2 when the weight of the N2 becomes less than WsH.
Supply it so that it becomes H. Note that at this time, the supply feeder 6 maintains a stopped state.

Further, during the above control, when the weight of the article in the weighing tank 8 reaches the lower limit value WT-, the supply feeder 6 also starts operating.

At this time, the computing unit 20 uses the measurement signal of the measurement device 11.18 to calculate the flow rate Q of the discharge feeder 10 according to equation (2).
52 is calculated. Based on this flow rate Q32, the controller 1
4 and feeder controller 16 to control the flow rate qS2 of the discharge feeder 10.

When the weight of the article in the weighing tank 8 returns to the upper limit value WH, the supply feeder 6 is stopped, and the computing unit 20 again computes the flow rate QS+ of the discharge feeder 10 based on the weighing signal from the weighing device 11. Based on this, the controller 14 and feeder controller 16 control the flow rate Q5j of the discharge feeder IO.

In the above embodiment, the arithmetic unit 20, the controller 14, the feeder controller 16, etc. are used, but a microcomputer may be used instead of these.

A flowchart in that case is shown in FIG.

Effects> As described above, according to the present invention, even while supplies are being supplied from the storage tank to the measuring tank, the goods can be discharged from the measuring tank in response to measurement signals from the measuring devices of the storage tank and the measuring tank. The flow rate of the discharge feeder can be calculated and the flow rate of this discharge feeder can be controlled. Therefore, the flow rate can be controlled with higher precision.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of a metering supply apparatus according to the present invention, FIG. 2 is a flowchart of the second embodiment, and FIG. 3 is a block diagram of a conventional metering supply apparatus. 2... Storage tank, 6... Supply feeder (supply device), 8
...Measuring tank, 10...Discharge feeder (discharge device),
11.18...Measuring device, 2o...Calculating unit (calculating means), 1- - Patent applicant Yamato Seiko Co., Ltd.

Claims (1)

[Claims] (1) A storage tank containing an article therein, a measuring tank provided below the storage tank, a supply device for supplying the article from the storage tank to the measuring tank, and a supply device provided in the measuring tank for discharging the article. Based on the discharge device, a measuring device provided in the storage tank and the measuring tank, and signals from both measuring devices in the operating state of the feeding device and the discharging device, and the head of the article flowing from the feeding device into the measuring tank. A quantitative supply device comprising: calculation means for calculating the discharge flow rate of the discharge device; and control means for controlling the discharge flow rate of the discharge device based on the discharge flow rate and a reference flow rate.