JP2000258325A - Density-judging apparatus by acoustic volumeter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for automatically generating a sorting judgment output to avoid sorting errors and a poor working efficiency caused when a density is simply measured and digitally displayed to sort fruits or the like with use of a density meter obtained by integrating an acoustic volumeter and an electronic balance in one system. SOLUTION: An object 3 to be measured is placed on a pan of an electronic balance 10 and a mass of the object is measured. The object on the pan is covered with a measurement container 2 of an acoustic volumeter and a volume of the object is measured. A density of the object is calculated from a ratio of the mass and volume. The calculated density and a preliminarily supplied density class boundary value are compared with each other by a comparing device. A judgment output is generated from a relationship, i.e., large or small of the density and the class boundary value. Whether the object is good or not is displayed by a lamp or a class is displayed in characters according to the output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acoustic volumetric meter and an electronic balance for measuring the density of a solid object having a complicated shape or a liquid contained in a container by using alternating pressure change of gas, that is, sound. The present invention relates to a density determination device based on an acoustic volume meter that generates a determination output such as the quality of an object to be measured according to a value of a measured density in a densitometer in which the density is integrated into one system.

[0002]

2. Description of the Related Art Although the sugar content of fruits and the fat percentage of meat have a strong correlation with their density, the measurement of the volume required for calculating the density has conventionally been based solely on the weight-in-water method using the law of buoyancy. Has been used. However, this method has drawbacks such as wetting and damaging the object to be measured and time and labor, and is not always widely used.

On the other hand, the applicant has disclosed Japanese Patent Application Laid-Open No.
In No. 16, etc., an alternating volume change is differentially given to both the reference container and the measurement container, and the ratio of the magnitude of the pressure change of the gas in these vessels at that time, that is, the magnitude of the sound pressure From the ratio, independent of the magnitude of the alternating volume change and unaffected by the static pressure of the gas in the vessel,
An acoustic volume meter for measuring the volume of an object placed in a measurement container in a dry state is shown.

In Japanese Patent Application Laid-Open No. 9-79965 (hereinafter referred to as the prior invention), the applicant has integrated the acoustic volume meter and the electronic scale as one system,
This shows a density meter that puts the object to be measured into the measuring tank of the acoustic volume meter on the tray of the electronic scale and immediately calculates the density of the object from the output of the volume meter and the output of the electronic scale. Was. The applicant further discloses in Japanese Unexamined Patent Publication No. Hei 10-170499, a food fat percentage measuring device for determining the fat percentage of meat using the measurement formula given in advance from the density of meat thus measured. Disclosed.

[0005]

In the density meter of the invention of the prior application, the measured density is substituted into a regression equation which is previously obtained experimentally to estimate the sugar content of the fruit. In the field, if the density of fruits is compared with a certain boundary value and classified into acceptable products and rejected products, or if it is sufficient to be able to classify into first, second, and third grades according to the density There are many.

In such a case, simply by measuring and displaying the density of the object as in the densitometer of the prior application, the measurer himself has to perform the comparison and comparison between the measured density and the boundary value of the class. There is a lot of mistakes and work efficiency is not improved.

An object of the present invention is to provide the density meter of the prior application with a function of automatically generating a judgment output indicating to which class a measured density value belongs, and to perform the above-described sorting. An object of the present invention is to provide a device for improving work efficiency.

[0008]

According to one aspect of the apparatus of the present invention, a reference container, a measurement container, a speaker for providing an alternating volume change to these two containers differentially, and a pressure inside each of these two containers. A volumetric measuring head composed of a microphone for detecting a change is placed over an object to be measured placed on a pan of an electronic balance. Then, the output of the microphone is taken into the signal processing device, and the volume of the object is measured from the ratio of the sizes thereof, and the output signal of the electronic balance representing the mass of the object is also taken into the signal processing device. The density of the object is calculated from the value of the volume, but further, by a comparing device coupled to the signal processing device, comparing the calculated value of the density with a class boundary value of the density given in advance. , A determination output indicating which class the calculated density belongs to is generated.

[0009]

According to the above, once the object to be measured is placed on the pan of the electronic scale, whether the object passes or rejects or belongs to which class is determined by a lamp, alarm sound, In addition, since it is indicated by letters such as first grade, second grade, and third grade, the number of errors in the object sorting work based on the density can be reduced and the work can be reduced compared to the prior invention which digitally displays the numerical value of the density of the measured object. Efficiency also increases. In the following,
The structure, operation principle, operation, and the like of the device of the present invention will be described with reference to an embodiment in which the object to be measured is a fruit.

[0010]

The [First Embodiment] In FIG 10 in an electronic scale, its volume V ₃ on top of the pan _8, the mass is placed is an object to be measured 3 M _3. Gravity applied to the tray 8 is transmitted to the electronic balance 10 by the support 9, converted into an electric signal E, and
Is sent to the signal processing device 15 through.

[0011] 2 volume when the air is in a cup-shaped measuring container V _0, but are overmolded on the object to be measured 3, coproduct V ₂ In this case,

[0012]

(Equation 1)

## EQU1 ## A reference container 1 having a volume V ₁ is provided on the measurement container 2, and a communication pipe 5 is provided on a partition wall 19 between these two containers, and the communication between the containers 1 and 2 is established. I have. A speaker 6 of a sound source is provided on this partition.
Is also attached. Reference numeral 7 denotes a speaker diaphragm.
A speaker 18 is connected to a conductor 18 through terminals 17 and 17 '.
And 18 'are connected, and an alternating drive signal is supplied from the signal generator 16 through these conductors, and an alternating volume change is differentially applied to the measuring container 2 and the reference container 1 by the front and back of the diaphragm 7. .

Reference numeral 11 denotes a microphone of a pressure transducer for detecting a change in pressure inside the reference container 1, and an output e ₁ of the microphone is sent to a signal processing device 15 through a conductor 20. 12 is a microphone of a pressure transducer for detecting the internal pressure change in the measuring vessel 2, and its output e ₂ is terminal 13 is sent to the signal processor 15 through a conductor 20 '. As described above, the reference container 1, the measurement container 2, the speaker 6, and the microphones 11 and 12 constitute a volumetric measurement head.

The signal processor 15 converts e ₁ and e ₂ from analog to digital and takes them in, measures their sizes, determines the volume V _{3 of the} object 3 from the ratio of the sizes, and obtains the volume V ₃ from the electronic balance 10. Of the object 3 by taking the signal E of
₃ , the density D = M ₃ / V ₃ of the object ₃ is calculated and displayed. Reference numeral 27 denotes a conductor which supplies a synchronizing pulse for the analog-to-digital conversion of e ₁ and e ₂ to the signal processing unit 15. The analog-to-digital conversion is performed independently of the drive signal of the sound source by signal processing. It may be performed in synchronization with the clock inside the device, in which case the conducting wire 27 is unnecessary.

[0016] Now, a speaker 6 by a signal from the signal generator 16 is driven and as a result the diaphragm 7 is pushed by the coproduct V ₂ of the measuring vessel 2 shall be compressed by a small volume comprising [Delta] V _S, volume _{V 1} of the reference container 1 is expanded by [Delta] V _S. Further, Δ is inserted into the measurement container 2 through the communication pipe 5.
Assuming that a small volume of gas of V _P flows in, a gas of ΔV _P volume flows out of the reference container 1 through the communication pipe 5. At this time, the pressure changes occurring inside the reference container 1 and the measurement container 2 are -ΔP ₁ and ΔP ₂ , respectively.

[0017]

(Equation 2)

In other words, from the relational expression of adiabatic compression of gas,

[0019]

(Equation 3)

[0020]

(Equation 4)

## EQU1 ## Here P ₀ is the average hydrostatic pressure of the container 1 and 2 inside the gas, gamma (gamma) is the specific heat ratio of gas. From the above two equations

[0022]

(Equation 5)

Or

[0024]

(Equation 6)

The following relationship is obtained. Since V ₁ is a constant value in the above equation, the ratio of the magnitude of the pressure change (ΔP ₁ / ΔP ₂ )
It is possible to know the coproduct V ₂ by measuring. Since the empty volume V ₀ of the measurement container is also a constant value, the volume V ₃ of the measured object ₃ is

[0026]

(Equation 7)

It is obtained by the following relational expression.

In the above description, the communicating pipe 5 functions to balance the static pressures inside the reference vessel 1 and the measuring vessel 2 and to equalize the gas components in both vessels. However, components such as humidity are hardly different between the two. Thus instead of the communicating pipe 5, can be used only capillary for balancing the static pressure, in this case, the volume [Delta] V _P of the gas passing through it is negligible very small. In an actual apparatus, the static pressure inside the container 1 is usually equal to the outside atmospheric pressure through a gap when the apparatus is assembled. Therefore, it is usually necessary to further provide a communication pipe or a capillary. Is not required.

FIG. 2 shows an example of the configuration of the signal processing device 15. The output signals e _{1 of the} microphones 11 and 12
And e ₂ are amplified in amplifiers 21 and 22, respectively, and then converted into analog / digital converters 23 and 2 respectively.
4 is converted into a digital quantity by the digital computer 2
It is taken in by 5. Reference numeral 26 denotes a frequency multiplier, which frequency-multiplies a synchronizing pulse supplied from the signal generator 16 through the conducting wire 27 to obtain a sampling pulse, which is sent to analog-to-digital converters 23 and 24. Perform the conversion.
However, this part is, as described above, the signal processing device 1.
5, a clock pulse generator may be provided, and the analog-to-digital conversion may be performed by the clock pulse independently of the signal generator 16. The start of analog-to-digital conversion is controlled by a start pulse sent from digital computer 25 to lines 23 and 24 through leads 29 and 30.

When the alternating signal for driving the speaker 6 is a sine wave, the output signals e ₁ and e ₂ of the microphones 11 and 12 also become sine wave signals. The data is Fourier transformed to precisely measure the amplitudes E ₁ and E ₂ of e ₁ and e ₂ , which represent the magnitude of the pressure changes ΔP ₁ and ΔP ₂ . That is, in the digital computer 25, according to the equation (7),

[0031]

(Equation 8)

A measurement formula is created, and the volume V _{3 of the} measured object 3 is determined by the formula. The drive signal of the speaker 6 is not limited to a sine wave, but a rectangular wave or an irregular signal may be used. In these cases, the amount representing the magnitude of the pressure change ΔP ₁ or ΔP ₂ is an average effective value rather than an amplitude. It is more appropriate to use such as. Note that the constants of V ₀ and V ₁ in Expression (8) can also be experimentally determined by calibration using a standard object whose volume is known.

The analog-to-digital converter 28 converts the output signal E from the electronic balance 10 into a digital quantity and takes it into the digital computer 25. The start of the conversion is started by the digital computer 25 and given to the lead 28 through the conductor 31. This is done by a pulse. The internal digital computer, a mass M ₃ of the object to be measured 3 by dividing the volume V ₃ obtained as described above was calculated density D of the object 3 to display represented by E. Some electronic balances output serial or parallel digital signals. In this case, 28 is unnecessary, and the output of the electronic balance is directly connected to the input interface circuit of the digital computer.

In the above description, it is assumed that the volume and the mass of 3 are measured with the object 3 and the volumetric measuring head placed on the pan 8. At this time, the mass of the volume measuring head is removed in advance by using the reset function of the electronic scale so that only the mass of the object 3 is displayed and output. However, since the conductors 18, 18 'to the speaker 6 and the conductors 20, 20' for the microphone output are connected to the volumetric measuring head, if the suspended state of these conductors changes from measurement to measurement, the mass measurement by the electronic scale will take place. Causes an error. Effect of the mass of the conductor, is remarkable particularly when small mass M ₃ of the object to be measured. To avoid this effect, measure its mass M ₃ put only first object to be measured 3 on the receiving tray 8, the digital computer the value of the mass 15
After the measurement, the measurement object 2 is covered with the measuring container 2 of the volumetric measuring head, and the volume V _{3 of the} object ₃ is measured.
The value of M ₃ which is stored so as to calculate the density D is divided by V _3.

In FIG. 1, reference numeral 33 denotes a comparison device. The calculated density D of the object 3 is transmitted through the conductor 32 to the comparison device 3.
3 is input. Q ₁ and Q ₂ are class boundary values of the density, and are introduced into the comparison device 33 through conductors 36 and 35, respectively. In the comparison device 33, D and Q ₁ , Q ₂
And Q ₁ <Q ₂ , D <Q ₁ ,
According to the three cases of Q ₁ <D <Q ₂ and Q ₂ <D, three types of determination outputs are output from the lead wire 34, and are displayed by the lamps, alarm sounds, characters, and the like for each color as described above.
The determination output may be output from one of a plurality of output lines corresponding to the determination result. When an object to be measured is divided into a pass product and a reject product according to the density, the above-described class boundary value is one value that separates both. When the class boundary value is 3 or more, the operation of the comparison device 33 is the same. The class boundary values Q ₁ and Q ₂ are the conductor 3
6 and 35, not only serially but also, for example, by a dial switch attached to the comparison device 33. In such a case, the conductors 36, 3
5 is unnecessary.

Although the above-described comparison operation can be easily performed by a digital computer, in this embodiment, since the signal processing device 15 includes the digital computer 25 for measuring the volume and calculating the density, The above comparison device 3
3 can be performed by this digital computer. At this time, as shown in FIG. 2, the comparison device 33 is incorporated therein as a part of the function of the digital computer 25, and does not exist as an apparently independent device. In this case, the class boundary values Q ₁ , Q ₂ are
Is a numerical value stored inside. The calculated object density D is also stored inside the digital computer 25. Therefore, the conducting wires 36, 35 and 32 are unnecessary.

[Brief description of the drawings]

FIG. 1 is a density determination apparatus according to a first embodiment of the present invention.

FIG. 2 is an example of a configuration of a signal processing device in FIG. 1;

[Explanation of symbols]

1 Reference container with volume V ₁ 2 Measurement container with volume V ₀ when empty ₃ Measurement object with volume V ₃ 5 Communication pipe 6 Speaker 7 Speaker 6 diaphragm 8 Receiving tray 9 Column 10 Electronic balance 11, 12 Microphone 13 Terminal 14 Conductor 15 Signal processor 16 Signal generator 17, 17 'Terminal 18, 18' Conductor 19 Partition 20, 20 'Conductor 21, 22 Amplifier 23, 24 Analog-to-Digital converter 25 Digital computer 26 Frequency multiplier 27 Conductor 28 Analog Digital converter 29, 30, 31, 32, 34, 35, 36 Conductor 33 Comparison device

Claims (1)

[Claims] 1. A measuring container containing an object to be measured, a reference container, means for differentially applying an alternating volume change to these two containers, and detecting a pressure change inside each of the two containers. A volumetric measuring head consisting of a means for performing the above is placed on a tray of an electronic scale, and an output signal of the means for detecting the pressure change and an output signal of the electronic scale are taken into a signal processing device,
In this signal processing device, the mass of the measured object represented by the output signal of the electronic balance is divided by the volume of the measured object obtained from the ratio of the magnitude of the output signal of the means for detecting a change in pressure to the measured object. The density of the measured object belongs to any class by comparing the value of the calculated density of the measured object with the class boundary value given in advance by the comparing device. A density judging device using an acoustic volume meter that generates a judgment output indicating whether the density is high or low.