JPH11183242A - Weight measuring method and powder fractioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required for a filling process by measuring the time τ required for an object to be measured from starting to fall toward a base till reaching the base estimating the weight of the object to be measured before reaching the base in the middle of falling, and adding it to the weight of objects to be measured already present on the base. SOLUTION: This device is provided with a filling head 21, a measuring hopper 24, and a filling control device 20. The filling control device 20 is provided with a coefficient setting part and a control part. The coefficient setting part calculates and records the time τ between the timing of opening a shutter 23 and the first detection of the impact above a threshold value at the load cell of a measuring device 5. The control part closes the shutter 23 at the time when a weight W1 detected by the load cell = W-Q.ατ(W: the target value of fractioning. Q: the amount of increase in weight in a unit of time, α: a correction value). In addition, the control part continues the state of a large amount of throwing-in with the shutter 23 at the maximum opening and controls the shutter 23 so as to limit the opening of the shutter 23 from the timing of closing the shutter 23 with the passage of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for measuring the weight of an object to be measured. The present invention is suitable for use in a factory production line. The present invention relates to a technique for stably measuring the weight of an object to be measured in an environment where vibration is generated on a table on which the object to be measured is placed for weight measurement. The present invention relates to powders (including powders)
Or, it was developed to fill a container with a prescribed amount of liquid in a short time, but can be widely used in other applications.

[0002]

2. Description of the Related Art When a product, such as a detergent, is a powder (including a granular material) or a liquid, the container is filled with a predetermined amount of the product powder or a liquid, and the product is filled. Sell. Therefore, this filling step is an important step in the production line. Hereinafter, a description will be given of a powder detergent as an example.

In the process of filling a container with a prescribed amount of powdered detergent, first, an amount of the powdered detergent in about 8 minutes is charged into the container (this is referred to as large input). Due to this large input, the weighing table on which the container is placed vibrates violently. Wait until the vibration converges and the measured value of the balance stabilizes, and then gently pour the remaining powder detergent so that the vibration of the weighing table does not occur again (this is called small pour).

Here, the reason why the powder detergent of about 8 minutes in the container is initially charged is that if more weight is added, the vibration of the balance becomes more severe and the time required for the vibration to converge is reduced. Because it becomes long. Further, at the time of this large loading, the balance vibrates, and it is difficult for the balance to measure the weight due to the vibration. Therefore, even if the balance is overloaded, it cannot be detected. Therefore, it is appropriate to set the maximum of about 8 minutes as the maximum value of the large input in consideration of avoiding excessive insertion.

FIG. 8 is a view for explaining a conventional filling method. The horizontal axis indicates time (sec), and the vertical axis indicates the filling amount (g). T as a stabilizing wait time scale in the example of FIG. 8 ₃
It takes -t _2. The time from the start of the large injection to the end of the small injection takes t ₄ −t ₁ . The shutter controlling the supply of the powder detergent is opened and closed twice for large supply and small supply.

[0006]

In order to improve the production efficiency, it is essential to shorten the time required for the production process, and there is a demand to shorten the time required for filling the powder detergent into the container. However, as described above, if the container is initially charged with a powder detergent having a weight close to the maximum weight in order to quickly fill the container, this will result in more vibrating vibrations on the scale, and the vibrations will take longer to converge. If you do not wait, you will not be able to measure weight accurately. In addition, the probability of an increase in the number of products that are overloaded and fail the inspection increases.

Further, in the conventional method, the shutter is closed after the large input, and the shutter is opened and closed twice in one process in order to wait for the balance to stabilize. Takes several seconds.

FIG. 9 is a diagram showing a collision noise and a natural vibration of the load cell. The natural vibration is a regular vibration generated when a certain instantaneous force is applied to the load cell, and the collision noise is an irregular vibration generated when the measured object collides with the load cell. Techniques for removing a natural vibration of a load cell by smoothing a signal by using a low-pass filter or a Kalman filter are known (JP-A-5-256687 and JP-A-7-25621).
6, JP-A-7-333045, Japanese Patent Publication No. 5-69175,
JP-A-2-22703). However, there is no disclosure of a technique for removing collision noise, which is irregular vibration caused by a collision of an object to be measured.

In order to solve this problem, the applicant of the present application has measured the weight of the object to be measured without waiting for the vibration of the balance to stabilize by a prior application (Japanese Patent Application No. 8-256773, not disclosed at the time of filing the application). Proposed technology that can be.

According to this prior application, the weight of the object to be measured that satisfies certain physical characteristics can be accurately measured without waiting for the vibration of the balance to stabilize. Further, there is no need to provide equipment having a complicated mechanism. However, the document does not mention measurement in a case where physical characteristics of an object to be measured are not constant.

In order to accurately measure the weights of the DUTs having different physical characteristics, it is necessary to appropriately change various measurement parameters. The procedure for changing the measurement parameters is automated. Accordingly, there is a demand for the development of a technique capable of accurately measuring the weight of an object to be measured even when the objects to be measured having different physical characteristics are mixed.

Japanese Patent Laid-Open Publication No. Sho 59-210325 discloses a technique for predicting the weight of contents discharged from a hopper and falling in the middle of a drop, and adding this to the weight of the contents to supplement the weight. However, there is no disclosure of a technique for coping with a change in the physical characteristics of an object to be measured. That is, in the case of a powder detergent or the like, the physical characteristics of an object to be measured change due to a change in manufacturing conditions. Therefore, in the method of estimating the weight of the contents during dropping based on the preset value, even if the physical characteristics change during the work and the flow rate and other values of the measured object change, the filling process is performed. And the weight value error increases.

The present invention has been made in view of such a background, and an object of the present invention is to provide a weight measuring method and apparatus capable of shortening a time required for a filling step. SUMMARY OF THE INVENTION It is an object of the present invention to provide a weight measuring method and apparatus capable of measuring the weight of an object to be measured without waiting for the convergence of the vibration of the scale. SUMMARY OF THE INVENTION It is an object of the present invention to provide a weight measuring method and apparatus capable of measuring the weight of an object to be measured regardless of the presence or absence of vibration of a scale on which the object is placed. An object of the present invention is to provide a weight measuring method and an apparatus capable of accurately measuring the weight of an object to be measured even when the objects to be measured having different physical characteristics are mixed. SUMMARY OF THE INVENTION An object of the present invention is to provide a weight measuring method and an apparatus capable of reducing the cost for uniforming the physical properties of a granular material in a powder detergent filling step.

[0014]

The time from when the shutter of the hopper storing the measured object is opened until the load cell actually starts detecting the weight of the measured object is defined as the falling time. This fall time varies with changes in the physical properties of the measured object. For example, in the case of a powder detergent, the bulk specific gravity differs between a case where each one is composed of independent particles and a case where it is composed of a large lump of a large number of particles, and the resistance value received from air during the fall time is different. Therefore,
The fall time varies depending on the physical characteristics of the device under test.

The most important feature of the present invention is to measure the fall time at the beginning of the filling step and reflect the measurement result in the step to perform accurate weight measurement. Further, the present invention is characterized in that a quick and accurate filling step can be realized by correctly detecting the timing when one filling step is completed and shifting to the next filling step and resetting the measurement system.

That is, a first aspect of the present invention is a weight measuring method, in which an object to be measured is continuously dropped on a table supported by a load cell to increase the weight of the object on the table. This is a weight measuring method for measuring the weight of the load cell by an electric signal corresponding to the displacement of the load cell. The feature of the present invention is to measure the time τ from when the object to be measured starts falling toward the table and reaches the table, and is in the process of falling toward the table and still reaches the table. Where the weight of the DUT that has not been measured is estimated based on the time τ and the increase per unit time of the DUT that has reached the table, and is added to the weight of the DUT already on the table. is there.

Thus, the physical characteristics of the object to be measured can be detected in the first part of the filling step and reflected in the subsequent steps, so that accurate measurement of the weight of the object to be measured can be performed. Note that τ is preferably measured every time, but the object of the present invention can be achieved if the measurement is performed once within about 5 to 10 times or about 10 minutes.

A second aspect of the present invention is a method of cutting out powder, which continuously drops powder on a table supported by a load cell to increase the weight of the powder on the table. In this method, the weight is measured by an electric signal corresponding to the displacement of the load cell, and the falling of the powder is stopped when the weight reaches a target value.
The feature of the present invention is that the time from when the powder starts falling toward the table to when the powder reaches the table is measured, and the powder is in the process of falling toward the table and is still on the table. Where the weight of the powder that has not arrived is estimated based on the time τ and the increase per unit time of the DUT arriving at the table, and is added to the weight of the DUT already on the table. It is in.

At this time, the powder is stored in a hopper,
It is desirable to measure the time τ as the time from when the shutter provided at the discharge port of the hopper is opened to when an impact exceeding the first threshold is detected in the load cell.

Further, a time τ from when a shutter provided at the discharge port of the hopper in which the powder is stored is opened to when an impact exceeding the first threshold is detected in the load cell is measured, and the shutter is operated. The closing timing is determined by the detected weight of the load cell. W ₁ = W−Q · ατ where W is a target value of cutout Q is an increase in weight per unit time (flow rate of powder) α is a correction value (shutter and powder) (Depends on the characteristics of the above). It is preferable that the powder is dropped so that the shutter is kept in a large throw-in state with the maximum opening, and the shutter opening is controlled to be narrowed with time from the closing timing.

According to a third aspect of the present invention, there is provided an apparatus for cutting out powder, in which a hopper for storing powder, a shutter provided at a discharge port of the hopper, and a continuous drop from the discharge port. A powder cutting device comprising: a table supported by a load cell for measuring powder; and control means for controlling timing of opening and closing the shutter. A feature of the present invention is that the control means measures and records a time τ from when the shutter is opened to when an impact exceeding a first threshold is detected in the load cell, and W ₁ = W −Q · ατ where W is the target value for cutting out Q is the increase in weight per unit time (flow rate of powder) α is the correction value (depends on the characteristics of the shutter and the powder) and the shutter is closed And means for doing so.

It is preferable that the correction value α is provided with means for automatically calculating α = τ ′ / τ when an average value of the time τ measured a plurality of times is τ ′.
This makes it possible to cope with the case where the physical characteristics of the device under test change every moment.

[0023] The means for closing includes means for controlling the shutter to be closed with a maximum opening degree, and controlling the shutter opening degree to be reduced with the passage of time from the timing of closing the shutter. Is desirable.

According to a fourth aspect of the present invention, there is provided a machine-readable recording medium on which software related to the control means is recorded.

A fifth aspect of the present invention is a method for measuring powder, wherein a shutter provided below a measuring device for measuring the weight of powder by a load cell is opened to drop the powder, After the shutter is opened, the weight of the object to be measured in the weighing device becomes zero after a lapse of a predetermined time after the detected weight of the weighing device has become zero a predetermined number of times, and the next weighing is started. And

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of a main part of a filling control device according to an embodiment of the present invention. FIG. 2 is a diagram showing the overall configuration of the embodiment of the present invention.

The present invention relates to a powder cutting device shown in FIG. 2, which is a filling head 21 serving as a hopper for storing powder.
A shutter 23 provided at a discharge port of the filling head 21, and a weighing hopper 24 which is a table supported by a weighing device 15 including a load cell 2 for measuring powder continuously falling from the discharge port; This is a powder cutting device including a filling control device 20 which is a control means for controlling the opening / closing timing of the shutter 23.

Here, a feature of the present invention is that the filling control device 20 determines the time τ from the timing when the shutter 23 is opened to the time when the load cell 2 of the weighing device 15 detects an impact exceeding the first threshold value. A coefficient setting unit 11 which is a means for measuring and recording; W ₁ = W−Q · ατ, where W is a target value for cutting out, Q is an increase in weight per unit time (flow rate of powder) α is a correction value (shutter And depending on the characteristics of the powder). The coefficient setting unit 11
Then, when the average value of the time τ measured a plurality of times is τ ′, the correction value α is automatically calculated as α = τ ′ / τ.

The controller 12 controls the shutter 23 to keep its large opening state at the maximum opening degree, and controls the shutter opening degree to be reduced with the passage of time from the closing timing of the shutter 23.

Also, a machine readable recording medium on which software related to the control section 12 is recorded is inserted into a software reading device of a personal computer device, and the software is read to control the personal computer device. It can be used as the unit 12. Similarly, the entire filling control device 20 can be realized by a personal computer device.

Further, the coefficient setting unit 11 includes parameters modeling the repulsive force k and the resistance c generated when the measuring device 15 is pressed, and the filter unit 7 calculates the displacement of the load cell 2 that changes with time t. Assuming that x (t), the collision speed of the measured object with the weighing hopper 24 is U ₀ , and the gravitational acceleration is G, the weight value m (t) is m (t) = [(− k × x (t) − c · dx / dt) /
(((Dx / dt−U ₀ ) · d / dt) + (d ² x / d
t ² ) −G)].

The collision velocity U ₀ is obtained by measuring the collision velocity of an object having a specific physical property as an object to be measured when the object is dropped from a predetermined height, and held in the coefficient setting unit 11. .

The control unit 12 generates an output signal when the weight value calculated by the filter unit 7 reaches a predetermined weight value, and automatically adjusts the supply of the powder detergent based on the output signal. Is controlled.

The coefficient setting section 11 stores in advance the vibration pattern of the weighing hopper 24 generated when the powder detergent is removed from the weighing hopper 24,
2 detects this pattern and resets a value obtained by an electric signal corresponding to the displacement of the load cell 2 to zero.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The operation of the embodiment of the present invention will be described. The present invention is embodied in a powder cutting device shown in FIG. 2 for filling a container with a prescribed amount of powder detergent. A powder detergent is stored in the filling head 21. This powder detergent is used for the shutter 23.
The specified amount is transferred to the weighing hopper 24 by opening and closing, and further transferred to the container 26 by opening and closing the input shutter 27. At this time, the weight of the powder detergent in the measuring hopper 24 is measured by the measuring device 15 supporting the measuring hopper 24.

As shown in FIG. 1, the load cell of the measuring device 15 is pushed down by the weight of the powder detergent, and generates a voltage proportional to the displacement. This voltage is amplified by the signal amplifier 3 and input to the low-pass filter 4. The output of the low-pass filter 4 is converted into a digital signal by an AD converter 5 that samples at 1 kHz. The conversion unit 6 converts the output of the AD converter 5 as the output weight value of the load cell 2. The filter unit 7 inputs the output weight value of the load cell 2 and outputs the weight value of the powder detergent.

In the embodiment of the present invention, the output weight value vibrates violently due to a large input impact, and increases as the number of objects to be measured increases. The filter unit 7 logically absorbs the vibration by performing an operation using the coefficient set by the coefficient setting unit 11. This weight value is displayed on the display 9
Is displayed as a number. Further, a control signal can be sent to the automatic control device of the production line by the output device 8.

The present invention is characterized in that the weight can be measured accurately even if the physical properties of the powder detergent as the object to be measured change. In the production of powders, it is difficult to make the particle size completely uniform. By using the present invention, the cost of uniformizing the particle size can be reduced.

In the embodiment of the present invention, the shutter 2 shown in FIG.
3 to detect a change in physical characteristics by measuring the difference between the time when the load cell 3 is opened and the time when the load cell 2 detects the weight.
This is reflected in the filling process. The change in physical properties can also be detected from the fact that the rate of increase in weight differs for each measurement.

Here, the modeling of the load cell will be described with reference to FIGS. FIG. 3 is a diagram showing a modeled load cell. FIG. 4 is a flowchart showing a coefficient setting algorithm. Figure 3 shows load cell 2
Is modeled by the repulsive force k and the resistance c as shown in FIG. An object having a known weight W ₀ is placed on the load cell 2, and an instantaneous force is applied to generate a natural vibration of the load cell 2. As shown in FIG. 4, first, a known weight W ₀ and the number of times of sampling N are set (S1). Initialization (j
= 0) (S2), and the load cell output weight value is sampled (S3). The first derivative dw _j / dt relating to time and the second derivative d ² w _j / dt ² relating to time are determined (S4). Then, (1 / (w _j −w ₀ )) · (w ₀ / G) · (d ² w _j /
dt ² ) and (1 / (w _j −w ₀ )) · (dw _j / dt) to form a data set (S 5). The above procedure is repeated up to a preset number of sampling times N (S
6). Repulsion k by the method of least squares using a set of N data
And the resistance c are determined (S7). The repulsive force k and the resistance c can be determined by the least squares method because of a linear relationship between these data sets. When the repulsive force k and the resistance c are k <0 or c <0, the measurement is performed again. Otherwise (S8), the flow ends. The coefficient of the filter unit 7 is set using the load cell 2 modeled in this way.

In the embodiment of the present invention, the repulsive force k and the resistance c are obtained by the method shown in FIG. 4, the collision speed U ₀ of the powder detergent is separately measured, and the filling process in the powder detergent production line is controlled. FIG. 5 is a flowchart showing the operation of the filling process in the powder detergent production line. The start switch is turned on, the charging time measurement timer is started, and a signal is taken from the load cell 2 to start weight measurement. At this time, the filter output weight value is sequentially received as weight measurement data (S11). The shutter 23 is moved to the large insertion position to perform the large insertion (S12). At this time, the time from when the shutter 23 of the filling head 21, which is a hopper storing the powder detergent, is opened until the load cell 2 actually starts to detect the weight of the powder detergent is defined as the drop time, and the coefficient setting is performed. The unit 11 measures the falling time (S13). The coefficient setting unit 11 corrects the fall time according to the measurement result (S14).

Further, a signal is fetched from the load cell 2 (S15), and the voltage value of the load cell 2 is converted into a weight value by the conversion unit 6 via the signal amplifier 3, the low-pass filter 4, and the AD converter 5. When this weight value passes through the filter unit 7 (S16), a weight value output W is obtained (S1).
7). The flow rate is calculated in accordance with the weight value output W, and a flow value output Q is obtained (S18).

At this time, the filter unit 7 performs sampling to take in the weight value, and outputs the weight value output W and the flow value output Q.
Get. The number of sampling buffer points is the number of data storage addresses of the sampling buffer. If the number of data exceeds the number of storage addresses, the oldest data is discarded and the latest data is fetched. This sampling buffer is provided in the filter unit 7.

Here, the correction of the drop time is to set the drop time used in the current filling step without directly using the drop time measured in the previous filling step.
By doing this, it is possible to perform calculations corresponding to changes in the physical properties of the powder detergent.

More specifically, ΔW is a value obtained by subtracting the weight w already output from the filter unit 7 when the shutter 23 moves to the large loading position from the final filling amount, and τ is the previous drop time, τ ′ Is the current drop time, τ ′ = ΔW / Q, and α = τ ′ / τ, that is, correction is performed as τ ′ = α × τ. If the current filling step is not the first filling step from the start of operation and there are falling times measured before that, the average value of these and the current falling time is set to τ ′.

Further, a large input predicted amount can be obtained as Q · τ ′ + W (S19). This means that a value obtained by multiplying the weight value output W by the flow value output Q and the drop time τ ′ is added. Here, Q · τ ′ indicates that the filling head 21 is moved before the shutter 23 moves to the small insertion position. And the weight value of the falling powder detergent that has not yet reached the weighing hopper 24. If the predicted large insertion amount is equal to or larger than the large insertion target amount (S20), the shutter 23 is moved to the small insertion position to start small insertion (S21). At this time, it is obvious that the flow value output Q changes according to the physical characteristics of the powder detergent.

The signal from the load cell 2 is fetched (S2
2) The filter unit 7 obtains the weight value output W at each time point from the weight values sampled as described above (S2).
3, S24). Further, the flow rate is calculated every moment according to the weight value output W, and the flow rate value q at this time is obtained (S25).

Here, the amount of head ΔW is predicted according to the relational expression ΔW = f (q) between the flow rate q and the amount of head ΔW obtained before filling (S2).
6). Here, the drop amount ΔW is a weight that increases after the shutter 23 is fully closed. This relational expression is obtained by measuring the flow rate q _i (i is a natural number) and the head fall amount ΔW _i at the opening degrees of the plurality of shutters 23, respectively, and obtaining the least square method. When the filling amount becomes equal to or less than the amount obtained by subtracting the drop amount from the target filling amount by this prediction (S27), the shutter 23 is closed and the weighing is completed (S28).

Subsequently, the closing shutter 2 of the weighing hopper 24
7 is opened to start charging the container 26 (S2).
9). The completion of the charging is confirmed (S30). Since the confirmation of the completion of the charging is not directly related to the present invention and thus will not be described in detail, it can be confirmed by measuring the weight of the container 26 or measuring the capacitance. If the container is transparent, it may be confirmed by a photoelectric switch.

Next, the vibration pattern of the load cell 2 is detected (S31), and when the signal level becomes zero a predetermined number of times (S32), it is considered that the loading is completed. That is, when the powder detergent is transferred from the measuring hopper 24 to the container 26, the powder detergent drops into the container 26 when the input shutter 27 is opened. At this time, a vibration is generated, but is stabilized after zero is repeated several times (FIG. 6). Since this number is determined by the dynamic characteristics of the weighing device 15 and the load cell, it is determined that this is a predetermined number and that the stability has been achieved. The output of the load cell when stabilized has a value different from the value corresponding to zero weight. This is because some powder has adhered to the hopper. In order to correct this deviation, the correction value used for the processing in the filter is changed so that this value is set to zero and the next weight measurement is started (S3).
3).

FIG. 6 is a diagram showing measured data of the embodiment of the present invention, in which the horizontal axis represents time and the vertical axis represents weight. FIG.
FIG. 6A shows the output of the load cell, and FIG. 6B shows the value of which the vibration has been removed by the filter unit and zero-corrected. At time t0, filling is started with the opening of the shutter 23 set to the large opening. The period from time t0 to time t1 corresponds to the previous falling time τ. At time t2, the opening degree of the shutter 23 is set to the small opening degree.
Is controlled at time t2 + τ ′, which is obtained by adding the above, so as to reach the large input target amount. At time t3, the shutter 23 is closed. At this time, the shutter 23 is closed so as to reach the target filling amount at time t4 from the relational expression between the flow rate q and the drop amount ΔW. At time t4, the charging shutter 27 of the measuring hopper 24 is opened, and the powder detergent is charged into the container 26. When the powdered detergent is transferred from the weighing hopper 24 to the container 26, when the input shutter 27 is opened, the powdered detergent falls on the container 26 along the inner wall of the input shutter 27. Vibration as shown in FIG. 6 occurs when connecting the inner wall. At time t5, the completion of feeding is confirmed, and at time t6
Since the output of the load cell has become zero three times, which is the predetermined number of times of this device, a time interval from time t7
The output of the load cell 2 is changed to zero according to the procedure described above. Since the above method is used, when filling 1500 g of the powder detergent into the container, the filling step can be completed in about one fifth of the conventional time.

FIG. 7 is a flowchart showing the operation of the filter unit 7. First, initialization is performed with i = 0 and m ₀ = 0.0 (S41). Subsequently, the sampling of the load cell output weight values (w _i) is performed (S42). A first-order differential dw _i / dt with respect to time, determining the second derivative d ² w _i / dt ² with respect to time (S43). Subsequently, [(1 / k · dw / dt) −U ₀ ] dm / dt + [(1
^{/ K · d 2 w / dt} 2) -G ] · m (t) = - w -c / k
Solve dw / dt using data collected sequentially. As the difference solution here, I m _i = _{[(- w i -c / k ·} dw i / dt) / (1 / k
_{· Dw i / dt-U 0} ) ] Delta] t - [[(1 / k · d ²
w _i / dt ² -G) / (1 / k · dw _i / dt-
U ₀ )]-1] m _i-1 was used (S44). Thus performing the output WT _i = m _i × G of the weight WT _i at the sampling timing T _i (S45).

Although the embodiment of the present invention has been described by taking a powder detergent as an example, the present invention can be similarly applied to a powder or a granular material or a liquid.

[0054]

As described above, according to the present invention,
The time required for the filling step can be reduced. That is, the weight of the object can be measured without waiting for the vibration of the balance to converge. Further, even in a situation where objects to be measured having different physical characteristics are mixed, the weight of those objects can be accurately measured. Further, the cost required for dehumidification in the step of filling the powder detergent can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a main part of a filling control device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the overall configuration of an embodiment of the present invention.

FIG. 3 is a diagram showing a modeled load cell.

FIG. 4 is a flowchart showing a coefficient setting algorithm.

FIG. 5 is a flowchart showing an operation of a filling step in a powder detergent production line.

FIG. 6 is a view showing actual measurement data of the example of the present invention.

FIG. 7 is a flowchart showing the operation of the filter unit.

FIG. 8 is a view for explaining a conventional filling method.

FIG. 9 is a diagram showing collision noise and natural vibration of a load cell.

[Explanation of symbols]

 Reference Signs List 2 Load cell 3 Signal amplifier 4 Low-pass filter 5 AD converter 6 Conversion unit 7 Filter unit 8 Output device 9 Display device 10 Calibration device 11 Coefficient setting unit 12 Control unit 15 Meter 20 Filling control device 21 Filling head 22 Shutter driving device 23 Shutter 24 Weighing hopper 25 Closing shutter drive 26 Container 27 Closing shutter

Claims (7)

[Claims] 1. An object to be measured is continuously dropped on a table supported by a load cell to increase the weight of the object to be measured on the table, and the weight of the object is increased by an electric signal corresponding to the displacement of the load cell. A weight measurement method for measuring, in which the time τ from when an object to be measured starts falling toward the table to reach the table is measured, and the object is in the process of falling toward the table and still reaches the table. Estimate the weight of the unmeasured object based on the time τ and the increase per unit time of the measured object arriving at the table, and add the weight to the weight of the measured object already on the table. Characteristic weight measurement method. 2. The method according to claim 1, wherein the powder is continuously dropped on a table supported by the load cell to increase the weight of the powder on the table, and the weight is measured by an electric signal corresponding to the displacement of the load cell. , A method of cutting out a powder that stops falling of the powder when its weight reaches a target value, from when the powder starts falling toward the table until it reaches the table. The time τ is measured, and the weight of the powder that is falling toward the table and has not yet reached the table is calculated based on the time τ and the increase per unit time of the measured object that has reached the table. A method for cutting out a powder, comprising estimating and adding to a weight of an object to be measured already on the table. 3. The powder is stored in a hopper, and the time τ is defined as a time from when a shutter provided at a discharge port of the hopper is opened to when an impact exceeding a first threshold is detected in the load cell. 3. The method for cutting out a powder according to claim 2, wherein the measurement is performed as: 4. A method for continuously dropping powder on a table supported by a load cell and increasing the weight of the powder on the table while measuring the weight of the powder by an electric signal corresponding to the displacement of the load cell. A method for cutting out the powder when the weight reaches a target value, wherein the powder is stopped from falling when a shutter provided at a discharge port of a hopper in which the powder is stored is opened. The time τ until an impact exceeding the first threshold is detected in the load cell is measured, and the timing for closing the shutter is determined by the detected weight of the load cell W ₁ = W−Q · ατ where W is the target value Q for cutting out. A method for cutting out powder that is set when the increase in weight per unit time (flow rate of powder) α becomes a correction value (depending on the characteristics of the shutter and the powder). 5. A hopper for storing powder, a shutter provided at a discharge port of the hopper, a table supported by a load cell for measuring powder continuously falling from the discharge port, and the shutter. Control means for controlling the opening / closing timing of the powder, wherein the control means controls a time τ from when the shutter is opened to when an impact exceeding a first threshold value is detected in the load cell. Where W ₁ = W−Q · ατ, where W is the target value of cutout Q is the increase in weight per unit time (flow rate of powder) α is the correction value (characteristics of shutter and powder) Means for closing the shutter when the following condition is satisfied. 6. A machine-readable recording medium in which software according to claim 5 is recorded. 7. A shutter provided below a measuring device for measuring the weight of the powder by a load cell is opened, the powder is dropped, and after the shutter is opened, the detected weight of the measuring device becomes zero for a predetermined number of times. A method for weighing powder, characterized in that, after a lapse of a predetermined time, the next weighing is started assuming that the weight of the measured object in the weighing device has become zero.