JP4791302B2 - Weight measurement method - Google Patents

Description

  The present invention relates to a weight measuring method for measuring the weight of an object, and more particularly to a weight measuring method for measuring a weight in an environment in which a shaking occurs on a ship or the like.

On the ground, there are methods described in Patent Document 1 (Flexible Bag Packaging Device) and Patent Document 2 (Powder Automatic Filling Device) as a weight measurement method when filling a flexible container bag with powder particles. . A flexible container bag is a large bag used to carry cargo such as food, feed, fertilizer, chemical industrial products, synthetic resin, cement, etc. Or a cylindrical shape.
JP 2004-299798 A JP-A-2005-75424

  In Patent Document 1, as described in FIG. 3 and paragraph [0023], a plurality of load cells are hung on an upper part of a support frame of a packaging cart, a flat support is attached to the load cell, and the flat support is provided. The flexible container bag is connected to the flexible container bag via the hoisting machine, the flexible container bag is lifted by the hoisting machine, the granular material is supplied from the upper filling device to the flexible container bag, and the weight can be measured by the load cell. A weight measurement method is disclosed.

  Further, in Patent Document 2, as described in FIG. 3 and paragraph [0022], an air cylinder is provided at the lower part of the frame of the automatic filling device, a load cell is attached between the air cylinder and the floor surface, and the air There is disclosed a weight measuring method in which a flexible container bag (or drum can) is lifted by a cylinder, powder particles are supplied from an upper filling device to the flexible container bag, and the weight can be measured by the load cell.

  Thus, when measuring the filling weight of a flexible container bag on the ground, a load cell or a spring balance is often used in a state where the flexible container bag is suspended or lifted. However, when such a measurement method is used in an environment where a shake occurs on a ship or the like, an acceleration due to the shake is applied to the object, and an accurate weight cannot be measured. In particular, when the flexible container bag is suspended or lifted together with the support frame or the frame of the automatic filling device, the weight applied to the measuring device is large, and the measurement error due to shaking increases.

Here, Patent Document 3 (weight measurement device including a motion correction device) discloses a weight measurement device capable of precise weight measurement in an environment where there is a motion such as a ship. In Patent Document 3, as described in FIG. 1, [Means for Solving the Problems], etc., it is a shake correction device used for an electronic balance, which is a measured weight F _x of an electronic balance and a measured weight F of a dummy balance. A weight measurement method is disclosed in which an unknown mass m _x is calculated from the values of ₀ and dummy mass m ₀ by a calculation formula of m _x = (F _x / F ₀ ) · m ₀ .
JP-A-11-132936

  However, the weight measuring device described in Patent Document 3 described above is suitable for measuring a precise weight with a small measurement value using an electronic balance, but is described in Patent Document 1 and Patent Document 2. It is not suitable for the case where the weight of the granular material in the flexible container bag is measured. This is because the weight measurement methods described in Patent Document 1 and Patent Document 2 have large measured values of several hundred kg and several thousand kg, and do not require precise measurement.

For example, when the weight of the granular material filled in the flexible container bag is 1000 kg and the weight of the weighing platform is 4000 kg, when the vertical acceleration due to shaking is 1.68 m / s ² , the error is 857 kg and the vertical acceleration due to shaking is Is 0.45 m / s ² , the error is 230 kg. If this error can be suppressed to within ± 0.01 g (g: gravitational acceleration) in the vertical direction, for example, within ± about 5 kg (about 1% when expressed as a percentage) in terms of weight in the above example. Good.

  Therefore, an object of the present invention is to provide a weight measurement method capable of reducing a weight measurement error by a simple method when acceleration generated in a measurement object fluctuates.

  According to the present invention, there is provided a weight measurement method used when measuring the weight of a measurement object in a place where the acceleration generated in the measurement object fluctuates, and a true weight is previously obtained in a place where the same acceleration as that of the measurement object occurs. A preparatory step for arranging a dummy weight that measures the weight of the dummy weight and a weighing scale for measuring the weight of the dummy weight, a weighing step for simultaneously measuring the weight of the measurement object and the dummy weight, and a measured weight of the dummy weight The comparison step of comparing the measured weight with the true mass, and the measured weight of the measurement object measured simultaneously when the difference between the measured weight of the dummy weight and the true mass is within a predetermined range are adopted as normal measured values. A weight measuring method comprising the steps of:

  The place where the acceleration generated in the measurement object fluctuates may be a place on a floating structure that is shaken by a wave. Further, when the measurement object is a powder, a fluid, or a solid-liquid mixture filled in the bag, the measurement value of the measurement object adopted in the determination step is a predetermined set weight. In this case, if the measurement value is not determined to be a normal measurement value in the determination step, the measurement value may be set to the set weight. Even if it has reached, the filling of the measurement object into the bag may not be stopped.

  In the weight measuring method of the present invention, when the acceleration a applied to the gravitational acceleration g varies, particularly when the acceleration a periodically varies between the plus side and the minus side, the point where the acceleration a does not always occur (a = 0 point). The dummy weight is installed in the same environment as the measurement object, and the change in the measured value of the dummy weight is observed while simultaneously measuring the weight of the measurement object and the dummy weight. The measured weight of the measurement object when the measured value of the dummy weight is close to the true weight is adopted as the normal measured value. Therefore, although the exact weight of the measurement object cannot be measured, the weight suppressed within a certain error range can be measured by a simple method. It is particularly suitable for measuring weight on a floating structure that is shaken by waves. In addition, when the measurement object is a powder, fluid, or solid-liquid mixture filled in the bag, the bag is filled with powder or the like too little or excessively due to the changing acceleration a. Can be prevented.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS. Here, FIG. 1 is a conceptual diagram of a system configuration used in the weight measuring method of the present invention, FIG. 2 is a flowchart showing the steps of the weight measuring method of the present invention, and FIG. 3 is the process of the weight measuring method of the present invention. FIG. 4 is a graph showing the measurement result of the measurement object by the weight measurement method of the present invention.

  FIG. 1 shows an example of how to fill waste mud when filling a flexible container bag (bag) with earth and sand (solid-liquid mixture) generated by, for example, seabed excavation by an automatic filling device (not shown) installed on the ship. It is a system configuration conceptual diagram for measuring weight. As shown in FIG. 1, the flexible container bag 1 is placed on the weighing platform 2, and the inlet of the flexible container bag 1 is connected to the supply port 3 of the automatic filling device. The weighing platform 2 is installed on the hull structure 5 via a plurality of load cells (weigh scales) 4, and by measuring the weight of the flexible container bag 1 including the weight of the weighing platform 2, the filling (earth and sand) The weight of 6 is measured. That is, the weight of the filler (sediment) 6 can be obtained by subtracting the weight of the known weighing platform 2 from the measured value. At this time, the weight of the empty flexible container bag 1 may be subtracted. However, it is not always necessary to calculate the weight of the filler (earth and sand) 6.

  Hereinafter, for convenience of explanation, the “measurement object A” represents an object measured by the load cell 4, that is, the flexible container bag 1, the weighing platform 2, and the filling material 6 filled in the flexible container bag 1. To do. Note that the weighing device for the filling 6 is not limited to the one described in FIG. 1, and may be one described in Patent Literature 1 or Patent Literature 2. In this case, the measurement object A is a flexible container bag and It represents the filling filled in the flexible container bag.

  In the present invention, a dummy weight 8 is installed via a load cell (weighing scale) 7 on the hull structure 5 that generates the same acceleration as that of the measurement object A, and the load cell 4 and the load cell 7 are measured simultaneously. The measurement value is transmitted to the control device 9, and the measurement result is displayed on the display 10 such as a display screen. By configuring such a system, a preparation step of disposing a dummy weight 8 whose mass is measured in advance and a load cell (weighing scale) 7 for measuring the weight of the dummy weight 8 at a place where the same acceleration as that of the measurement object A occurs. Is completed. As a matter of course, a weight scale may be used instead of the load cell.

  According to the weight measurement system shown in FIG. 1, the weighing step in which the load cell 4 and the load cell 7 simultaneously measure the weight of the measurement object A and the dummy weight 8 is compared with the measured weight of the dummy weight 8 with the true weight mt. A comparison step, and a determination step of adopting the measured weight of the measurement object A measured simultaneously when the difference between the measured weight of the dummy weight 8 and the true weight mt is within a predetermined setting range as a normal measured value; A weight measuring method is provided that includes a stopping step of stopping filling of the filling material (earth and sand) 6 into the flexible container bag 1 when the measured value of the adopted measurement object A reaches a predetermined set weight Ms. be able to. Therefore, the control device 9 shown in FIG. 1 is responsible for at least the comparison step and the determination step.

  Next, functions of the control device 9 will be described with reference to FIG. When filling of the filling material (earth and sand) 6 into the flexible container bag 1 is started (S1), the load cell 4 and the load cell 7 simultaneously measure the weight of the measurement object A and the dummy weight 8 at a predetermined timing (S2). The measurement result is transmitted to the control device 9. The control device 9 compares whether or not the measured weight of the dummy weight 8 is within the set range (S3). The setting range can be determined so that the true mass mt ± 1% of the dummy weight 8 or the acceleration of the dummy weight 8 is within a range of ± 0.01 g (g: gravitational acceleration). For example, when the dummy weight 8 is 10 kg, the setting range is 9.9 kg to 10.1 kg. When the measured weight of the dummy weight 8 does not exist within this set range, it is processed as an abnormal measured value with a large error due to shaking, and the measured weight of the measurement object A is ignored and handled as an invalid measured value (S6). Filling is continued (S7).

  If the measured weight of the dummy weight 8 exists within the set range, it is next determined whether or not the measured weight of the measurement object A has reached the set weight Ms (S4). Here, when the measured weight of the measuring object A has reached the set weight Ms, the filling is stopped (S5), and when it has not reached the set weight Ms, the filling is continued (S7). Here, in the operations of filling stop (S5) and filling continuation (S6), the control device 9 and the automatic filling device are electrically connected, and the filling is automatically stopped or continued according to the determination result of the control device 9. Alternatively, the determination result of the determination step (S4) is displayed on the display 10, the operator checks the screen of the display 10, and the automatic filling device is manually stopped or continued. Also good.

  Further, the order of the comparison step (S3) and the determination step (S4) can be changed as shown in FIG. When the determination step (S4) is performed prior to the comparison step (S3), if the measured weight of the measurement object A has not reached the set weight Ms, the filling is continued (S7). If the measured weight has reached the set weight Ms, the process proceeds to the comparison step (S3). In a comparison step (S3), it is compared whether or not the measured weight of the dummy weight 8 is within the set range. If the measured weight of the dummy weight 8 is within the set range, the filling is stopped as a normal measured value. (S5). If the measured weight of the dummy weight 8 is out of the set range, the measured weight of the measurement object A is ignored and treated as an invalid measured value because it is an abnormal measured value (S6), and filling is continued (S7). .

  According to the flow shown in FIG. 2 and FIG. 3, in any flow, not only the measured weight of the measurement object A but also the measured weight of the dummy weight 8 is referred to, and acceleration due to shaking occurs. It is possible to determine whether or not it occurs, and even when the measured weight of the measuring object A reaches the set weight Ms, the filling of the filler (sediment) 6 is performed in an excessively small state. It can be continued without stopping. Similarly, the filling material (earth and sand) 6 is not excessively filled. In particular, the present invention was created by paying attention to the fact that in a floating structure such as a ship that is shaken by waves, the shake is periodic and always passes through a point where acceleration due to the shake does not occur. This method allows the weight to be measured almost accurately. Note that the “substantially accurate weight” means a weight suppressed within a certain error range.

  FIG. 4 is a graph showing measurement results obtained by the weight measurement method of the present invention, in which (A) shows the measurement object A and (B) shows the measurement results of the dummy weight 8. 4A and 4B, the vertical axis represents weight (kg) and the horizontal axis represents time (seconds).

  The true weight mt of the dummy weight 8 is constant regardless of the passage of time, as shown by a one-dot chain line in FIG. Further, the setting range is a range sandwiched by solid lines in FIG. 4B, and by setting the upper limit setting weight mu and the lower limit setting weight md, the lower limit setting weight md to the upper limit setting. A range of weight mu is set. The upper limit set weight mu and the lower limit set weight md of this setting range depend on the size of the flexible container bag 1, the state of shaking (waves), the nature of the filling (fluidity, contamination degree, specific gravity, etc.), filling speed, etc. It can be arbitrarily set, and it is preferable that the touch panel type display 10 can be set. When the filling of the flexible container bag 1 is started, the weight of the dummy weight 8 is continuously measured by the load cell 7, and the measurement result is displayed as shown by a solid broken line in FIG. In addition, although an accurate measurement result shows a waveform close to a sine wave, it is simplified and displayed as a broken line here.

  Since the dummy weight 8 is now connected to the hull structure 5 on the ship, the result is that the measured weight rises and falls at a substantially constant cycle as shown in FIG. In addition, since the generated fluctuation is due to waves, it always passes through a point where the acceleration a applied to the gravitational acceleration g is zero. Accordingly, as shown in FIG. 4B, the measured weight of the dummy weight 8 periodically crosses the set range. In the present invention, the measured weight of the measuring object A corresponding to the time zone (t1 to t2, t3 to t4, t5 to t6, t7 to t8, t9 to t10) within the set range is a normal measured value. Process as.

  As shown by a solid broken line in FIG. 4A, the measurement weight of the measurement object A periodically rises and falls due to shaking, and rises to the right as the filling amount increases. At this time, there is always a true weight (weight when acceleration a other than gravitational acceleration g is not generated), and for example, it can be displayed as a one-dot chain line. Further, the trigger for stopping the filling of the flexible container bag 1 is set as a set weight Ms indicated by a solid line in FIG. In this figure, the accurate measurement result shows a waveform in which the sine wave rises to the right, but here it is simplified and displayed as a broken line.

  Here, for example, assuming that the dummy weight 8 is not installed, the measured weight of the measurement object A reaches the set weight Ms at T1, and the filling into the flexible container bag 1 is stopped. However, in this case, since the acceleration due to the shaking occurs, the error e1 with the true weight M1 becomes large. At the timing of T1, since the filling was stopped with a measured weight larger than the true weight M1, the filling amount into the flexible container bag 1 becomes too small, and the flexible container bag 1 is unnecessary and flexible. The container bag 1 is frequently replaced, resulting in inefficient operation. However, in the present invention, since the measured weight at the timing of T1 is out of the set range by the dummy weight 8, it is processed as an abnormal measured value, and can be continued without stopping the filling. Can be implemented.

  And if the flexible container bag 1 is filled with the filling (sediment) 6 using the weight measuring method of this invention, the time slot | zone t1-t2, t3-t4, t5-t6, t7-t8 within a setting range. Then, the measured weight of the measuring object A does not reach the set weight Ms, and reaches the set weight Ms at the timing T2 in the time period t9 to t10. In this case, since the measured weight of the dummy weight 8 is within the set range and the measured weight of the measurement object A has reached the set weight Ms, the filling of the filling material (earth and sand) 6 into the flexible container bag 1 is stopped. It will be. Although the timing of T2 is shorter than the time Ts when the true weight reaches the set weight Ms, the error e2 from the true weight M2 at the timing of T2 is small. In FIG. 4A, it is obvious when the magnitudes of the error e1 and the error e2 are compared.

  Therefore, according to the present invention, the error from the true weight can be suppressed within a certain range, and the flexible container bag 1 is unnecessarily flexible without causing the filling amount of the flexible container bag 1 to be too small or excessive. The flexible container bag 1 is not unnecessarily replaced frequently, and an efficient operation can be performed.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

It is a system structure conceptual diagram used with the weight measuring method of this invention. It is a flowchart which shows the process of the weight measuring method of this invention. It is a flowchart of other embodiment which shows the process of the weight measuring method of this invention. It is a graph which shows the measurement result by the weight measurement method of this invention, (A) has shown the measurement object, (B) has shown the measurement result of the dummy weight.

Explanation of symbols

1 Flexible container bag
2 Weighing base 3 Supply port 4 Load cell (Weigh scale)
5 Hull structure 6 Filling (earth and sand)
7 Load cell (Weigh scale)
8 Dummy weight 9 Control device 10 Display

Claims (5)

A weight measurement method used when measuring the weight of a measurement object in a place where acceleration generated in the measurement object fluctuates,
A preparatory step of arranging a dummy weight that has measured a true weight in advance in a place where the same acceleration as that of the object to be measured occurs and a weight scale that measures the weight of the dummy weight;
A weighing step for simultaneously measuring the weight of the measurement object and the dummy weight;
A comparison step of comparing the measured weight of the dummy weight with the true weight;
A determination step of adopting, as a normal measurement value, the measurement weight of the measurement object measured simultaneously when the difference between the measurement weight of the dummy weight and the true weight is within a predetermined range;
The weight measuring method characterized by having.   The weight measurement method according to claim 1, wherein the place where the acceleration generated in the measurement object fluctuates is a place on a floating structure that is shaken by a wave.   The weight measurement method according to claim 1, wherein the measurement object is a powder, a fluid, or a solid-liquid mixture filled in a bag.   4. The filling of the measurement object into the bag body is stopped when the measurement value of the measurement object adopted in the determination step reaches a predetermined set weight. Weight measurement method. In the determination step, if it is not determined that the measurement value is normal, the filling of the measurement object into the bag body is not stopped even if the measurement value has reached the set weight. The weight measuring method according to claim 4, wherein