JPH04305280A - Device for measuring size of solid - Google Patents

Abstract

PURPOSE:To accurately measure the size by enlarging a processing ability per hour and to more accurately measure the size of the solids in various shapes. CONSTITUTION:The solid is brought into a measuring electrode 1 comprised of a first electrode 1A and a interlaced electrode 1B, and by measuring changes in the capacitance of the measuring electrode 1, the size of the solid is measured. The first electrode 1A and the interlaced electrode 1B are arranged in the posture crossing an electrode plate 4.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates primarily to a device for measuring the size of solid objects such as fruits such as chestnuts, vegetables, or fish, and in particular, the present invention relates to a device for measuring the size of solid objects such as fruits such as chestnuts, vegetables, or fish, and in particular, measures the size using changes in capacitance. related to a device for

0002

2. Description of the Related Art Apparatuses for sorting solids such as chestnuts by size have already been developed. Conventional devices for achieving this include weight sensors. This device measures the weight of a solid object by placing it on a weight sensor. The weight sensor can use a piezo effect or a mechanism that detects the amount of spring extension.

0003

[Problems to be Solved by the Invention] Weight sensors can accurately measure weight if processing capacity is not an issue. However, as the time for measuring one weight is shortened, the measurement error increases significantly. This is because the inertial force affects the gravity of the solid material when it is transported. As long as a solid object is placed on a weight sensor and measured, inertial force cannot be completely eliminated. The inertial force increases in proportion to the height at which the solid object is dropped onto the weight sensor and the speed at which the solid object is supplied to the weight sensor. Placing the solid object on the weight sensor slowly and quietly can reduce measurement errors due to inertial force. However, weight sensors cannot increase the processing capacity per hour. For this reason, a device that continuously measures the weight of solids requires about 3 seconds to measure one piece, and its processing capacity is limited to about 1000 pieces per hour.

[0004] The present invention was developed with the aim of solving this drawback of conventional devices, and an important purpose of the present invention is to increase the processing capacity per hour and accurately measure the size. The goal is to provide a device that can perform measurements. Another important object of the present invention is to provide an apparatus that can more accurately measure the size of solid objects of various shapes.

[0005]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the apparatus for measuring the size of a solid substance according to the present invention has the following configuration. (a) The device for measuring the size of a solid object consists of a measuring electrode 1 that uses the principle of a capacitor to detect changes in capacitance when a solid object passes between electrode plates, and a capacitance of the measuring electrode 1. The measuring device is equipped with a calculating means 2 for detecting a change in the solid material and calculating the size of the solid material, and a conveying means 3 for transporting the solid material between the measuring electrodes 1. (b) When the measurement electrode 1 passes a solid object,
Two electrode plates 4 are provided so as to sandwich the solid material transfer path so that the capacitance changes. (c) The measurement electrode 1 includes a first electrode 1A and a crossed electrode 1B in order to more accurately measure the size of solid objects of various shapes. (d) The first electrode 1A and the crossed electrode 1B are the electrode plate 4
are arranged in such a way that they intersect with each other. (e) The calculation means 2 has a first electrode 1A and a crossed electrode 1B.
By measuring the change in capacitance when a solid object passes through,
It is configured to calculate the size of solid objects.

[0006]

[Function] The apparatus for measuring the size of a solid substance according to the present invention measures the size of a solid substance by the following function. Two electrode plates 4 arranged apart from each other form a capacitor. The capacitance of the capacitor is proportional to the area of the electrode plates 4, inversely proportional to the distance, and further proportional to the dielectric constant of the material between the electrode plates 4. The capacitance changes when a solid object is carried between the two electrode plates 4 and when there is no solid object. This is because the dielectric constant of solid matter is different from that of air. Therefore, the change in capacitance between the two electrode plates 4 becomes larger as the solid material becomes larger.

By the way, in a device that measures the size of a solid object based on a change in capacitance, the shape of the solid object causes errors. This is because the capacitance of the electrode plate 4 changes depending on the posture even if solid objects of the same size are carried in. The capacitance is different when the same solid substance is carried in between the electrode plates 4 in the attitude shown in FIG. 4 and when it is carried in in the attitude shown in FIG. Since the solid object carried in in the attitude shown in FIG. 5 approaches the electrode plate 4, the capacitance becomes larger compared to the attitude shown in FIG. Therefore, when a change in capacitance of the electrode plate 4 is detected and its size is measured, an error occurs depending on the posture.

The device of the present invention is equipped with a mechanism for reducing errors due to posture. Intersecting electrode 1B and first electrode 1A
The capacitance of a solid object is measured using the 3D and 3D sensors to reduce errors due to posture. That is, a solid object is introduced into the measuring electrodes 1 that intersect with each other, and the size of the solid object is measured from a change in the capacitance of both electrode plates 4.

FIG. 6 shows the change in capacitance of the first electrode in which the electrode plates are arranged horizontally and the cross electrodes in which the electrode plates are arranged vertically, and the weight of the chestnut. Moreover, FIG. 7 is a graph showing the average value of the capacitance of the first electrode and the crossed electrode, and the weight of the chestnut. The measurement results in this figure show that the average value of the capacitance of the first electrode and the crossed electrode has a considerably small measurement error with respect to the weight of the chestnut. In other words, by measuring the size of the chestnut from the capacitance of the first electrode and the crossed electrode, it is possible to measure it more accurately.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. However, the embodiments shown below are illustrative of a measuring device for embodying the technical idea of the present invention,
The measuring device of this invention is characterized by the material, shape, structure,
The arrangement is not limited to the following structure. The measuring device of this invention can be modified in various ways within the scope of the claims.

[0011]Furthermore, in order to make the claims easier to understand, this specification uses numbers corresponding to members shown in the examples as "claims" and "means for solving the problem." It is added to the members shown in the "Column". However, the members shown in the claims are by no means limited to the members of the embodiments.

The apparatus for continuously measuring the size of solid objects shown in FIG.
It is equipped with

The measuring electrode 1 includes two electrode plates 4 forming a capacitor. When a solid object is introduced between the two electrode plates 4, the capacitance changes depending on the size of the solid object. Therefore, the electrode plates 4 are arranged to sandwich the solid material transfer path.

The measurement electrode 1 includes a first electrode 1A and a crossed electrode 1.
It is equipped with B. The first electrode 1A and the intersecting electrode 1B are arranged so as to intersect with each other. In the measuring device of FIG. 1, the electrode plate 4 of the first electrode 1A is arranged horizontally, and the electrode plate 4 of the crossed electrode 1B is arranged vertically. That is, the measuring device shown in the figure has a first electrode 1A and a crossed electrode 1B disposed orthogonally to each other. When the measurement electrodes 1 are disposed horizontally and vertically in this way, the two sets of measurement electrodes 1 have the advantage of reducing measurement errors due to the shape of solid objects. Another reason is that by narrowing the interval between the electrode plates of the first electrode 1A, the amount of change in capacitance can be increased.

However, in the measuring device of the present invention, the first electrode 1A and the intersecting electrode 1B do not necessarily need to be disposed orthogonally. By arranging the first electrode 1A and the intersecting electrode 1B so as to intersect with each other, the size of the solid object can be measured more accurately than with one set of measurement electrodes 1. therefore,
Preferably, the angle formed by the electrode plate 4 of the first electrode 1A and the crossed electrode 1B is adjusted to be in the range of 30 degrees to 150 degrees. Furthermore, although not shown, by using a plurality of intersecting electrodes 1B, the size of the solid object can be measured more accurately.

Furthermore, as shown by the chain lines in FIG. 1, it is also possible to provide two sets of first electrodes 1A. A mechanism for rotating the solid object by 90 degrees in a horizontal plane is provided between the two sets of first electrodes 1A. In this way, solid objects can be carried into the two sets of first electrodes 1A in different postures. That is, the measurement electrode 1 having this structure can measure the capacitance of a solid object by arranging the electrode plate 4 in the directions of the XYZ axes that are orthogonal to each other. Therefore, the measuring device having this structure can measure the size more accurately than calculating the size by measuring the amount of change in capacitance in two directions. The simplest mechanism for rotating solids in a horizontal plane is a rod 5 suspended vertically in the solids transport path. The rod 5 is rotated in a horizontal plane by collision with a portion of the solid material to be transferred.

The calculating means 2 calculates the size of the solid object from the capacitance of the measuring electrode 1. Therefore, the measurement electrode 1 is connected to the calculation means 2 via the lead wire. A block diagram of the calculation means 2 is shown in FIG. The calculation means 2 includes an oscillation circuit 6, an inverting amplifier circuit 7, a non-inverting amplifier circuit 8, a rectifier circuit 9, an integrating circuit 10, an A/D converter 11, and a digital calculation circuit 12. .

The oscillation circuit 6 preferably has a frequency of 100kHz.
It oscillates an AC signal of ~300MHz. Inverting amplifier circuit 7
amplifies the alternating current of the oscillation circuit 6 to a constant amplitude and inverts the phase. The non-inverting amplifier circuit 8 amplifies the oscillation circuit 6 to a constant amplitude without changing its phase. The output waveforms of the inverting amplifier circuit 7 and the non-inverting amplifier circuit 8 are adjusted to have opposite phases and the same amplitude.

The output of the inverting amplifier circuit 7 is connected to the input side of the rectifier circuit 9 via a series circuit of an electrode plate 4 and a resistor 13. The output side of the non-inverting amplifier circuit 8 is connected to the input side of a rectifier circuit 9 via a series circuit of a reference capacitor 14 and a resistor 13.

The rectifying circuit 9 of the reference capacitor 14 is adjusted to the capacitance of the measuring electrode 1 without introducing solid matter. Furthermore, both resistors 13 are adjusted to the same value. In this way, the capacitance of the reference capacitor 14 and the measurement electrode 1 are made the same,
Furthermore, if both resistance values are the same, the input signal to the rectifier circuit 9 will be zero when no solid matter is introduced into the measurement electrode 1. This is because the signal input from the inverting amplifier circuit 7 through the measurement electrode 1 and input into the rectifier circuit 9 and the signal input from the non-inverting amplifier circuit 8 through the reference capacitor 14 and input into the rectifier circuit 9 are in opposite phase. This is because they are at the same level. In this circuit, when a solid substance is introduced into the measuring electrode 1 and the capacitance of the measuring electrode 1 changes, the phase and amplitude of the signal passing through the measuring electrode 1 and input to the rectifying circuit 9 change. A signal corresponding to the amount of change is input to the rectifier circuit 9. Therefore, this circuit has the advantage of being able to measure changes in capacitance of the measurement electrode 1 by converting them into voltage.

The rectifier circuit 9 rectifies the input AC signal and inputs its output to the integrating circuit 10. FIG. 3 shows the output waveform of the rectifier circuit 9 when a solid substance passes through the measurement electrode 1. As shown in this figure, as solid matter is fed into the measurement electrode 1, the change in capacitance of the measurement electrode 1 increases, and the output of the rectifier circuit 9 increases. The change in capacitance is maximum when the solid material is completely fed into the measurement electrode 1, and thereafter, as the solid material is fed out, the change in capacitance becomes smaller.

Integrating circuit 10 integrates the output waveform of rectifying circuit 9. That is, the integrating circuit 10 integrates the change in capacitance from when the solid substance is introduced into the measurement electrode 1 until it is sent out. The integral value of the integrating circuit 10 corresponds to the size of the solid object. In this way, by integrating the change in capacitance from when a solid object is fed until it is sent out, and calculating the size of the solid object from this integrated value, the size can be measured more accurately. be. This is because changes in capacitance due to solid objects can be measured in many postures with one set of measurement electrodes.

However, according to the present invention, it is also possible to measure the size from the change in capacitance when a solid object is brought into a specific position of the measurement electrode, without depending on the integral value of the change in capacitance. Needless to say. In this case, it is preferable to measure the change in capacitance when the solid material is introduced into the center of the measurement electrode.

The output of the integrating circuit 10 is a function indicating the size of the solid object. The function between the output value of the integrating circuit 10 and the size of the solid object is calculated in advance by transporting a specially weighed solid object and stored in the memory 15. The output of the integrating circuit 10 is converted into a digital quantity by an A/D converter 11 and then input to a digital arithmetic circuit 12 . The digital arithmetic circuit 12 stores in the memory 15 a function for calculating the size of the solid object from the main force of the integrating circuit 10, and based on this function, calculates the size of the solid object from the output of the A/D converter 11. That is, calculate the weight.

The digital arithmetic circuit 12 calculates the signals input from the plurality of A/D converters 11 and stores them in the memory 15.
Calculate the size of the solid object based on the stored and memorized function. The conveyance means 3 is a belt conveyor that conveys the solids. The belt conveyor carries a solid object onto a synthetic resin belt 16 between the measurement electrodes 1 . The belt conveyor carries the solids into the measurement electrode 1 at regular intervals. The speed at which the belt conveyor conveys the solids to the measuring electrode 1 is preferably about 1 piece every 0.1 to 0.3 seconds.

The positions of the belt 16 and the electrode plate 4 are shown in FIGS. 8 and 9.
It is shown in As shown in this figure, the solid matter carried on the belt 16 passes between the measuring electrodes 1.

The belt 16 of the belt conveyor is an endless belt, and a portion thereof is cleaned by sprinkling water on it. Spraying water onto the belt 16 from the nozzle 18 in this manner has the advantage of increasing measurement accuracy. This is because foreign matter adhering to the belt can be removed and causes of errors can be reduced. Also,
When measuring the size of a solid object with water attached, belt 1
If water adheres to a part of the belt 6, it will cause an error, but by sprinkling water from a nozzle and applying water to the entire surface of the belt, errors caused by partial adhesion of water can be prevented.

In the passage of the belt conveyor, solid matter passage sensors 17 are provided on the inlet side and the outlet side of the measuring electrode 1. The passage sensor 17 detects that solid matter has passed, detects that the solid matter has been carried into the measurement electrode 1, and also detects that the solid matter has been discharged. Passing sensor 17
The signal resets the integration circuit 10 and is also input to the digital arithmetic circuit 12 to identify the solids to be transferred. Since the belt conveyor transports the belt at a constant speed, the calculation means 2 uses the signal from the passing sensor 17 to
The size of the solid matter is calculated by detecting that the solid matter that has passed through the electrode 1A is carried into the intersecting electrode 1B. A passage sensor 17 provided on the discharge side of the measurement electrode 1 resets the integration circuit 10. Therefore, the integrating circuit 10 integrates and outputs the amount of change in capacitance each time one solid object passes through the measurement electrode 1. The calculation means 2 includes a passage sensor 17 and an A/
The solid object is identified using the output signal of the D converter 11, and its size is calculated.

By the way, the measuring device of the present invention measures the size of a solid object from a change in capacitance. The weight of a solid is the product of its size and specific gravity, so if you know the specific gravity of a solid, you can calculate its weight from its size. Therefore, in this specification, size refers to volume, weight, or both.

[0030]

[Effects of the Invention] The device for measuring the size of a solid object according to the present invention carries a solid object between the electrode plates that constitute a capacitor, and
The size is measured from the amount of change in capacitance. Devices that can measure sizes in this state have extremely high throughput and are capable of accurate continuous measurements. This is because the inertial force of the solid object does not cause measurement errors.

Furthermore, the measuring device of the present invention measures the amount of change in capacitance using both the first electrode and the crossed electrodes. Therefore, the device of the present invention has the advantage of being able to more accurately measure the size of solid objects of various shapes with complex shapes.

[Brief explanation of drawings]

[Fig. 1] A perspective view of a solid object size measuring device showing an embodiment of the present invention.

[Figure 2] Block diagram showing an example of calculation means

[Figure 3
] Graph showing the input signal of the integrating circuit

[Figure 4] Plan view showing solid matter being carried into the measurement electrode

[Figure 5] Plan view showing solid matter being carried into the measurement electrode

[Figure 6] Graph showing the weight of solid matter versus the amount of change in capacitance

[Figure 7] Graph showing the weight of solids versus the average value of change in capacitance

[Figure 8] Cross-sectional view showing the positional relationship between the measurement electrode and the belt conveyor

[Figure 9] Cross-sectional view showing the positional relationship between the measurement electrode and the belt conveyor

[Explanation of symbols]

1...Measuring electrode 1A...First electrode 1B...Cross electrode 2...Calculating means 3...Transporting means 4...Electrode plate 5...Rod 6...Oscillating circuit 7...Inverting amplifier circuit 8...Non-inverting amplifier circuit 9...Rectifier circuit
10... Integrating circuit 11... A/D converter 12... Digital calculation circuit 13... Resistor 14... Reference capacitor 15... Memory
16... Belt 17... Passage sensor

Claims (1)

[Claims] 1. An apparatus for measuring the size of solid matter having the following configurations (a) to (e). (a) The device for measuring the size of a solid object includes a measuring electrode (1) between which the solid object passes, and a calculating means (2) that detects the capacitance of the measuring electrode (1) and calculates the size. and a conveyance means (3) for conveying solid matter between the measurement electrodes (1). (b) The measurement electrode (1) includes two electrode plates (4) arranged to sandwich the solid material transfer path. (c) The measurement electrode (1) includes a first electrode (1A) and a crossed electrode (1B). (d) The first electrode (1A) and crossed electrode (1B) are
The electrode plates (4) are arranged so as to cross each other. (e) The calculating means (2) measures the change in capacitance when the solid object passes through the first electrode (1A) and the crossed electrode (1B), and calculates the size of the solid object. It is composed of