JPH01263524A - Powder substance weighing method - Google Patents

Abstract

PURPOSE:To enable the dropping charge of an aimed weight reliability into a weighing hopper, by stopping the dropping charge of a powder substance from a charging port at the time point when a load cell measures the weight of the powder substance obtained by subtracting a head weight from the aimed weight. CONSTITUTION:The weight of a powder substance in a weighting hopper 12 in the course of the dropping charge thereof is measured a plurality of times at each unit time and also measured values at each unit time are averaged, whereby a flow rate X of the powder substance charged by dropping is detected. Besides, a head weight Y in the air is determined from the product tX of the amount X charged by dropping and a drop time (t) of the powder substance. At the time point when a load cell 13 of the weighing hopper 12 measures a difference W-Y between an aimed weight W and the head weight Y as the weight of the powder substance, the dropping charge of the powder substance from charging ports 6, 7 and 8 are stopped. Thereby a timing of blocking of the charging ports 6, 7 and 8 can be detected automatically while the powder substance is charged by dropping, and the powder substance can be charged by dropping into the weighing hopper 12 and weighed therein as much as the aimed weight reliably even when the kind of the powder substance and the flow rate of the substance charged by dropping are varied.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for measuring powder and granular materials.

<Conventional technology> FIGS. 4 and 5 are diagrams showing conventional examples of the present invention.

The method of measuring the powder 1 when the powder 1 is continuously dropped into the weighing hopper 3 from the input port 2 located at a certain height is to drop the powder 1 into the weighing hopper 3 while it is being dropped by the measuring means of the weighing hopper 3. The weight of the powder and granular material 1 is continuously measured, and the weighing pump 3
The measuring means detects the target type 1w of the powder or granular material 1, and at time t1
The inlet 2 is closed to stop the powder and granular material 1 from falling from the inlet 2.

<Problems to be Solved by the Invention> However, in such a conventional method for weighing powder or granular material, at the time t1 when the measuring means of the weighing hopper 3 detects the target weight W of the powder or granular material l, the input port is closed. 2, even after closing the input port 2, the powder 1 in the air that has not reached the weighing hopper 3 (to be exact, the top surface of the powder 1 that has been dropped and fed) Weighing hopper 3 as head weight Y
W+ is placed in the weighing hopper.
It was supposed that Y amount of powder and granular material 1 would be added in excess. This fall error Y becomes larger as the height position of the input port 2 is higher.

In order to avoid such overloading with drop error Y, it is conceivable to measure the weight after drop load during a test in advance, artificially predict the drop error Y in advance, and close the input port 2. It is troublesome to have to determine the predicted blockage point through repeated trial and error, and it is also a hassle (even if the predicted blockage point is determined, if the type of powder or granular material to be weighed changes, the head type i1Y will also change, so it cannot be applied) It was insufficient in terms of versatility and reliability.

This invention was made by focusing on such conventional technology, and it is possible to automatically detect the timing of blockage of the input port while dropping powder and granular material, and to detect the type of powder and granular material and the falling It is an object of the present invention to provide a method for weighing powder or granular material that can reliably drop and throw only a target amount into a weighing hopper even if the charging flow rate changes.

<Means for Solving the Problems> As a result of extensive research to achieve the above object, the inventors have discovered that the amount of powder and granules falling in per unit time (i.e., the falling flow rate) of the powder and granules increases. be constant for each type,
Focusing on the fact that the falling time of powder and granular material from the input port to the weighing hopper is approximately constant depending on the height regardless of the type of powder and granular material, it is possible to The weight of the head in the air is determined from the product of the input flow rate and the falling time of the powder, and the inlet is closed in front by the amount of the head.

Specifically, the weight in the weighing hopper is measured multiple times per unit time while the powder is being dropped into the weighing hopper, and
The falling input flow rate X of the powder and granular material is detected by averaging the measured values for each unit time, and the falling input flow rate and the falling time t of the powder and granular material are calculated.
The head weight Y in the air is determined from the product tX of It is.

<Embodiment> FIGS. 1 to 3 are diagrams showing a preferred embodiment of the present invention.

First, the structure of the weighing device according to this embodiment will be explained using FIGS. 1 and 2. 4 is a cut gate serving as an input mechanism, through which rice is supplied from above as powder and granules 5, and three input ports 6, 7, large, medium and small are provided below.
8 are provided respectively. And these three input ports 6
．． 7.8 are each equipped with opening/closing lids 9, 10, 11, and by rotating these opening/closing lids 9.10, 11,
First, from the large input port 6, then from the medium input lower, and finally from the smallest dispensing input port 8.
The powder and granular materials 5 can be dropped into the weighing hoppers 12 below.

The weighing hopper 12 is for receiving the powder or granular material 5 therein and measuring the weight of the powder or granular material 5.The weighing hopper 12 is for receiving the powder or granular material 5 inside and measuring the weight of the powder or granular material 5.
attached to. That is, the other end 15 of the load cell 13 is fixed to the frame 14, and one end 16 is fixed to the weighing hopper 12, and the total weight of the weighing hopper 12 distorts the load cell 13, so that the weight is measured. This load cell 13 is connected to a computer (not shown), so that data storage and arithmetic processing of the weight measured by the load cell 13 can be freely performed.

There is an outlet 17 at the lower end of this weighing hopper 12, and the
The outlet 17 can be opened and closed by an opening/closing lid 19 which is rotated by a protrusion 23 pushed by a motor-driven rotating shaft 18. A bag (not shown) is arranged below the outlet 17, so that the powder or granular material 5 weighed by the target weight can be directly packed into a bag. Further, near the side surface 20 of the weighing hopper 12, a receiving portion 21 is provided for receiving and stopping the powder and granular material 5 from the dispensing inlet 8. This receiving portion 21 can receive and stop the powder or granular material 5 by coming into contact with the side surface 20 of the weighing hopper 12.
It rotates by being interlocked with each other via the side surface portion 20, and the powder and granular material 5 that is separated from the side surface portion 20 and accumulated inside can be discharged into the weighing hopper 12.

Hereinafter, using this measuring device, 2 pieces of rice as powder and granules 5 will be measured.
The operation when weighing in kilograms will be explained.

First of all, it is necessary to shorten the overall time for dropping and introducing the powder and granular material 5 (open the largest input port 6 of the cut gate 4, and drop a certain amount of the powder and granular material 5 from there into the weighing hopper 12. Next, switch from the large input port 6 to the medium input lower, and further drop the powder and granular material 5 into the weighing hopper 12, and when it reaches around 2 kg, which is the target type 1w, the medium input Stop the dropping of the powder and granular material 5 from the lower.The dropping of the powder and granular material 5 through the input port 6.7 up to this point can be done roughly to some extent, and the powder and granular material 5 should be dropped and introduced until it reaches 2 kg, which is the target weight W. Good.

Finally, the powder or granular material 5 is dropped little by little from the dispensing inlet 8 into the receiving part 21 in the weighing hopper 12 with a constant falling input flow 31X. By dropping the powder and granular material 5 through the dispensing inlet 8, the powder and granular material 5 is accurately dropped and the target ZW of 2 kg is to be accurately weighed.

First of all, a few seconds after the start of dropping the powder and granular material 5 from the dispensing inlet 8, the dropping of the powder and granular material 5 becomes stable. 4-1-g falling input amount per unit time, that is, the falling input flow rate X is detected.

Here, using FIG. 3, a method of determining the falling input flow lx of the powder and granular material 5 will be explained. Approximately 0.5 seconds have passed since the start of dropping from the dispensing inlet 8, and 3 sampling times (1 sampling time = 33.33 n+5
ec) is 1 unit, and for each unit 10 times (to-t
9) Weight Wl of powder and granular material 5 in the bottom weighing hopper 12
- Measure W9. Then, from the measured weights W1 to W9 of each unit, weight change values SO to S4 of 5 units are once determined as follows.

W9-W4 = 34 W8-W3 = 33 W7-W2 =, 52 W6-Wl = 5l W5-WO=S.

Then, to ensure accuracy, the remaining three weight change values excluding the minimum and maximum among SO to S4 are averaged, and the weight change of the powder or granular material 5 per unit time is calculated, that is, the dispensing input port 8
The falling input flow rate X of the powder or granular material 5 can be instantaneously calculated and obtained by a computer. Once the falling input flow rate X is known, the remaining amount is determined by the following equation (1). The head weight Y, which is the amount of the granular material 5, can be easily determined.

y = tx+α ・−・・−・−・−(1) Y:
Head weight t; Time from when the powder leaves the inlet until it reaches the weighing hopper (the top surface of the dropped powder) Delay/Time lag due to sampling data processing) Here, t and α are values unique to the measuring device, so the data are input into the computer in advance.

Therefore, as soon as the falling input flow 1x is obtained, the head weight Y
can also be obtained simultaneously through arithmetic processing.

Therefore, the computer calculates the last weight measurement value W9, the drop input flow rate X, the head weight Y, the target weight W, and the target weight W9.
- The head weight Y is calculated, and the dispensing inlet 8 is closed at the timing T when the target weight W - the head weight Y is detected. By doing so, the dispensing slot 8
After blocking the granules 5, the powder 5 in the air with a falling error Y is dropped into the weighing hopper 12 and just falls into the 2nd part of the target mold 1w.
This means that only kg can be weighed.

After measuring the target weight W according to the above procedure, rotate shirt) 1B
, rotates the receiving part 21 that receives the powder and granules 5 from the dispensing inlet 8, and transfers the powder and granules 5 to the weighing hopper 12.
At the same time, open the opening/closing lid 19 to remove the weighing hopper 1.
Accurately measured powder or granular material 5 can be discharged from the outlet 17 at the lower end of the bag 2 into a bag (not shown) and packed into a bag.

The powder and granular material 5 according to this example was repeatedly weighed 50 times, and the error was within ±1 g.

<Effects> Since the method for measuring powder and granular material according to the present invention has the contents as explained above, it is possible to automatically detect the timing of blockage of the input port while dropping the powder and granular material into the powder. Even if the type of granules or the flow rate for dropping them changes, it is possible to reliably drop and weigh only the target amount into the weighing hopper. Therefore, there is no need for preliminary adjustment or test weighing to perform accurate dropping, and accurate weighing can be performed simply by dropping the powder or granules to be weighed from the outlet into the weighing hopper, making weighing work easier. It is extremely simple and accurate.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a measuring device according to an embodiment of the present invention, Fig. 2 is a side view seen from the direction indicated by the arrow in Fig. 1, and Fig. 3 is a change in weight of powder and granular material per unit time. FIG. 4 is a graph corresponding to FIG. 3 showing a conventional example of this invention.
FIG. 5 is an enlarged view showing a falling and charging state of powder and granular material according to a conventional example of the present invention. 5 - Powder 6.7.8 - Inlet 12 - Weighing hopper 13 - Load cell (measuring means) W - - Target weight Y - Head weight Fig. 2 Fig. 3 Fig. 4 N Samurai - 11

Claims (1)

[Claims] Powder and granular material is continuously dropped into a weighing hopper from an input port at a constant height, and the weight of the dropped granular material is measured by a measuring means of the weighing hopper. In addition, in a method for weighing powder and granular material that weighs powder and granular material having a target weight W, the weight in the weighing hopper while the powder and granular material is being dropped and fed is measured multiple times per unit time, and Average the measured values to detect the falling flow rate X of powder and granular material,
The weight of the head in the air Y is determined from the product tX of the falling input flow rate and the falling time t of the powder, and when the measuring means of the weighing hopper measures W-Y as the weight of the powder, the powder from the input port is A method for measuring powder or granular material characterized by stopping the dropping of granular material.