JPH01148916A - Quantitative weighing apparatus - Google Patents

Abstract

PURPOSE:To perform quantitative weighing with high accuracy, by operating the increase and decrease of the supply quantity corresponding to a set objective value and controlling the supply quantity of an article to be weighed. CONSTITUTION:An objective value input apparatus 3 sets the weighing objective value of a weighing apparatus 1 and the weighing data thereof is inputted to a control apparatus 4. A laser reflecting type detection apparatus 8 detects the variation in the thickness of the layer of the article S to be weighed transferred toward a weighing container 2 on a trough 6 to input the same to the control apparatus 4 which in turn controls the driving of an electromagnetic feeder 5 on the basis of the increase amount of the weighed value from the weighing apparatus 1 and an elapse time and operates a necessary increase/ decrease possible range corresponding to the difference between the weighing objective value and the weighed value at the present point of time. As a result, since the fine adjustment of the supply quantity is performed every time along with the adjustment of the required flow rate of the article S to be weighed, highly accurate quantitative weighing becomes always possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to measuring the layer thickness of an object to be weighed, such as powder or granular material, using a detection means such as a laser or an infrared reflection device in advance, when weighing a certain amount of the object to be weighed. The present invention relates to a novel quantitative measuring device that predicts the amount of an object to be weighed to be supplied to the measuring device by detecting fluctuations before the measuring device weighs it, thereby achieving highly accurate weighing.

BACKGROUND OF THE INVENTION In conventional devices for weighing a fixed amount of an object to be weighed such as powder or granular material, if the target weight of the object to be weighed is 100%, a trough etc. The supply device is driven at high speed to supply the object to be weighed, and when the weighing value of the scale reaches this value, the supply device is switched to low speed and continues supplying until the weight reaches 99%.
When it reaches the vicinity, the supply device is stopped, and the remaining 1
% is the correction amount, that is, the weight of the object that was still falling between the tip of the feeding device and the weighing device when the device stopped, the energy of the falling object that the weighing device is experiencing at that point, and the device. The oversupply generated due to the inertia of the drive system is measured as a head correction amount.

In this way, the amount of objects to be weighed to be supplied to the weighing device can be reduced to 80%.
%, 98%, for example, it is necessary to consider not only the performance at low speed driving, the unique properties of various objects to be weighed, and the target weighing time, etc., but also the The prerequisite is that the flow of the object to be measured is rectified.

Problems to be Solved by the Invention However, even if the objects to be weighed are of the same type, environmental conditions such as humidity levels, loading conditions in storage hoppers, storage time, etc.
It changes depending on the condition of the object to be measured when the arching brake force is activated. Therefore, when quantitatively weighing the object to be weighed accurately and in a short time, the speed setting value of the above-mentioned feeding device and the values of the shift point or stop point at the time of 80% and 88% feeding should be set to the target object. This poses a problem in that changes need to be made at any time depending on the object to be weighed, making the operation complicated.

For this reason, for example, "Unexamined Japanese Patent Publication No. 59-58118"
, "Unexamined Japanese Patent Publication No. 59-210325", "Unexamined Japanese Patent Publication No. 1983
-135727 Publication”, “Japanese Unexamined Patent Publication No. 80-228925
In Japanese Patent Laid-open Publication No. 80-238723j, attempts have been made to solve the problems in the above-mentioned conventional devices.

However, in the above-mentioned prior art, since the supply of the object to be weighed is controlled based on the result of the increase in weight after the object is fed to the weighing device, not only is the response at the time of supply delayed, but also the supply It is completely impossible to respond to unpredictable fluctuations in the object to be measured on the device.

Therefore, in order to solve the above-mentioned conventional problems, the present invention detects in advance a change in the state of the object to be weighed in the feeding device using a detection device, for example, a reflection detection device such as a laser or infrared ray. The purpose of the present invention is to provide a novel quantitative measuring device that can understand the behavior of objects to be weighed before they are weighed, and that can perform highly accurate quantitative weighing using its control functions.

Means for Solving the Problems In order to achieve the above object, the present invention provides a supply device for supplying an object to be weighed, a control device for controlling the supply amount to a set target value, and a supplying device for supplying the object to be weighed to a set target value; It consists of a weighing device that weighs the object to be weighed and inputs the measured value to a control device, and a detection device that is located near the feeding device and detects the object to be weighed. The behavior of the object is detected and inputted to the control device, and the control device calculates an increase or decrease in the supply amount corresponding to a set target value, thereby controlling the amount of the object to be measured by the supply device. It is.

Note that the detection device described above can be a device equipped with a laser or infrared reflection function.

A supply device that supplies the object to be weighed to the weighing device is driven by a control device, and supplies a target amount of the object to be weighed into the weighing device.

At this time, the behavior associated with the flow rate of the object to be fed is detected in advance by a detection device located near the feeding device, and the amount to be fed to the weighing device is predicted by inputting this information to the control device. At the same time, the supply of the object to be weighed is controlled in accordance with the difference between the target setting value input to the control device and the measured value. Therefore, the required flow rate of the object to be measured can be adjusted, and the supply amount can be finely adjusted each time, so that highly accurate quantitative measurement can be carried out at all times.

Example An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is an explanatory diagram showing the basic configuration and operation of the device according to the present invention. In the device shown in FIG. 1, 1 is a measuring device on which a measuring container 2 is placed, and this measuring device M1 is A measurement target value is set by the target value input device 3, and the calculated value data is input to the control device 4.

5 is an electromagnetic feeder drive coil, 6 is a trough driven by the output of this feeder 5, and 7 is a hopper that accommodates the object to be weighed S on this trough 6. ? This constitutes a supply device 1o.

Reference numeral 8 denotes a reflective detection device equipped with a laser or infrared rays for measuring variations in the layer thickness H of the object to be weighed S transferred onto the weighing container 2 on the trough 6; By inputting the measured layer thickness of the object S to the control device 4, changes in the thickness of the object S to be weighed during transportation on the trough 6 are detected and input to the control device 4. The supply flow rate of the object to be weighed S relative to the drive output of the feeder 5 in the device system is controlled based on the amount of increase in the measured value from the device 1 and the elapsed time, and the measurement target value set by the target value input device 3 is controlled. The amount of the object to be weighed S to be supplied is controlled by calculating the range in which the object to be weighed S can be increased or decreased in accordance with the difference between the measured value and the current measured value.

Next, using the above-mentioned apparatus, an unknown object S, for example, a powder-like object S! A case will be described in which the target weight value WF is measured with an allowable error of ±Ws. Before the start of measurement, the inside of the weighing container 2 is blank, so the input from the weighing device 1 to the control device 4 is O, and the weighing operation is started under this state. That is, by energizing and driving the electromagnetic feeder 5, the particulate weighing material S1 stored in the hopper 7 is transported forward in the direction of the arrow in the figure, and is stored in the weighing container 2 from the tip of the trough 6.

The measured value w1 at this time is stored in the control device 4, and the measured value w2 after an elapsed time of 11 seconds from this point is stored, and at the same time, the supply of the drive current I to the electromagnetic feeder 5 is cut off.

On the other hand, the detection device 8 detects the layer thickness of the powdery weighing material St on the trough 6 during the elapsed time t1 seconds, inputs the detected value to the control device 4, and calculates the average layer thickness HA from this measured value.

From this, the measured value stored in the control device 4, that is, (W2-11)÷tl=Q is calculated. Therefore,
This calculated value Q is calculated by applying the drive current I to the powder or granular weighing object S.
This is the flow rate of the particulate material to be measured per unit time when 1 is moved forward and the layer thickness is HA.

Next, the total weight w3 of the powder-like weighed object S1 is measured at the time when the measured value due to the feeding operation hardly changes. From this, the total weight w3-J2=Wa.

This Wa is the weight of the particulate matter Sl fed during the delay time to from when the stop signal to the feeder 5 is sent to when the drive current is cut off, that is, the flow rate Q
X to = the total amount including Wb and the collapse amount We of the weighed object Sl that fell from the tip of the trough 6 due to its own weight after the current I was cut off and the feeder 5 was stopped, and the above Wa = wb + Wc and Naru.

Therefore, the collapse angle of the object S1 on the trough 6 shown in FIG.
In the case of a powdery object to be measured S1, it is almost constant due to its properties, so the amount of collapse Wc is proportional to the square of its layer thickness H, and the flow rate Q is also a function n (powder Furthermore, when the current flow rate is constant, the layer thickness H of the powder-like object to be measured St and its flow rate Q are proportional.

The relationship between the driving current I and the layer thickness H of the powdery and granular material S1 is determined by the properties of the powdery and granular material S1 to be weighed and the storage hopper 7.
It is affected by the state of outflow from the powder to the trough 6, so it is not necessarily proportional, but it increases or decreases with a delay time due to the flow action inherent to the powdery weighed object S1, so it is roughly averaged. The trends of increase and decrease are almost the same. Here, the amount of collapse Wc is compared with the allowable error Ws, and the layer thickness Hs required to establish the desired relationship Ws>We is calculated and set as a temporary layer thickness.

Then, IXH';/HA=Ig is calculated from the correlation between the drive current value and the average layer thickness H, and is used as a temporary current value.

This Ig is regarded as the driving current when supplying the particulate material to be measured S1 with the target layer thickness Hs at the end of the measurement.

Next, the supply device M10 is restarted to start driving the feeder 5 with a current value of 1ss smaller than this Is, and at the same time start the metering operation.

Then, the time t2 until the time when the average layer thickness (IA) changes and becomes the temporary layer thickness Ha is determined, and the average flow rate QA during this time is calculated. Further, the object to be measured S1 is continued to be supplied while increasing/decreasing the current so as to maintain the temporary layer thickness Hs, and the current value at this time is stored in the control device 4, and the flow rate Qs during this time is also changed in the same manner as described above. The amount of collapse We is also measured in the same manner.

In other words, if the amount of collapse ≦l1lS, the above-mentioned temporary Ha, 1''eQa is obtained by using the layer thickness H and current I at this time as actual measured values.
Update and store the value.

At this time, if wc≦US, it goes without saying that the current I is changed again and the same operation is repeated until We≦l1ls is reached. The ratio to the amount of change in layer thickness is approximately proportional when the powder is smooth, for example, but is not necessarily proportional when it is sticky and crumbles irregularly, such as when it has a lot of moisture. Since these data are unique to the powder or granular material, these data are multiplied by the number of threads K of 1 or more in order to prevent over-weighing, as will be described later.

Then, subtract the current weight -N from the target value -F.

After calculating the weight to be supplied -〇, subtract the collapse amount at the final layer thickness Hs and the delayed supply Qs
Add 1llDD to the remaining weight after subtracting AXK. After that, while monitoring the ever-increasing WN and the changing 8% and constantly calculating the WDD, as long as ZengDD is an integer, I will be increased appropriately and Q will be increased to continue the supply. At the moment when DD becomes 0, change I to Ig, and then l becomes WF.
When the value becomes equal to -l1ls -(Q s

Ha, Is, Q! in the above explanation! Since this becomes known when the same powder or granular material is weighed after the next weighing, the weighing control operation is performed in the same manner as the operation after calculating the weight WDD, and the previous control operation is unnecessary.

In the event that a measured value is found to be defective, please correct K, Hs, and Is at the next time of measurement according to the content of the problem, or adjust the maximum value of layer thickness H if there are variations in measured value or measuring time. It goes without saying that automatic correction control, such as limiting the amount of time and reducing the variation in layer thickness reduction time, should be added.

2 to 5 show another configuration according to the present invention, in which the second UgJ supplies a constant weight of the object to be weighed S1 per unit time into the hopper 7, and this object to be weighed S1 is placed on the trough 8. A device 8 detects the amount of emissions flowing out to the supply destination and being supplied to the supply destination.
The third V! J has a configuration in which a conveyor 9 is attached to the above-mentioned apparatus, and a detection device 8 detects the variation in the layer thickness of the flow rate when the object to be weighed S1 is supplied onto the conveyor 10, and the amount of the supply is controlled. Figure 4 shows the above trough 6.
For the object to be weighed St above, a plurality of detection devices M8, 8 are provided to detect the layer thickness of the object to be weighed S1 to be fed at a plurality of positions, and the supply amount is controlled based on the difference in the change. FIG. 5 shows that a plurality of the above-mentioned detection devices 8 are installed at small intervals in the direction of the tip of the trough 6, and the amount of layer thickness variation with respect to the object to be measured 91 is detected depending on the installation position of each, This figure shows a configuration that further increases detection accuracy.

Effects of the Invention The quantitative measuring device of the present invention includes a supply device that supplies an object to be measured, a control device that controls the supply amount to a set target value,
The detection device consists of a weighing device that weighs a certain amount of the object to be weighed and inputs the measured value to a control device, and a detection device that detects the object to be weighed from the open surface of the supply device. This makes it possible to detect changes in the layer thickness of the object to be weighed before it is weighed, and from this, it becomes possible to predict and control the amount of the object to be weighed to be supplied to the weighing device.

Therefore, by inputting only the measurement target value into the control device, highly accurate quantitative measurement can be performed automatically in the shortest possible time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic configuration diagram thereof, and FIGS. 2 to 5 are schematic configuration diagrams showing different embodiments. l...Measuring device, 2...Measuring container, 3...Target value input device, 4...Control device, 5...Electromagnetic feeder, 6...Trough, 7...Hopper, 8...Detection device, 9... - Conveyor, 10... Supply device, Sl... Object to be weighed.

Claims (1)

[Claims] (1) A supply device that supplies the object to be weighed, a control device that controls the supply amount to a set target value, and a weighing device that weighs a certain amount of the object to be weighed and inputs the measured value to the control device. , a detection device located near the supply device to detect the object to be weighed; the detection device detects the behavior of the object to be weighed to be fed and inputs it to the control device; A quantitative measuring device characterized in that it is configured to calculate an increase/decrease in a supply amount corresponding to a set target value to control the supply amount of an object to be weighed by the supply device.