JP3883466B2 - Filler detection method and filler detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a filling detection method and a filling detection apparatus for detecting a filling state of concrete into a mold made of, for example, precast concrete.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a method of filling a concrete with a reinforcing bar disposed inside a formwork made of precast concrete (hereinafter referred to as precast concrete formwork) has been adopted for a building structure.
In recent years, the shape of precast concrete formwork has become complex due to diversification of design, etc., and a method that can easily detect whether the concrete is properly filled up to the end of the complex shape by nondestructive inspection is desired. It is rare.
[0003]
Examples of methods currently commercialized include those disclosed in JP-A-7-269120, JP-A-10-197467, or Japanese Patent No. 2836799, both of which are precast concrete type. It arrange | positions in a frame and detects the electric potential which generate | occur | produces when concrete contacts the two electrodes, and it is made to detect that the concrete was filled.
[0004]
In addition, as a method different from the above three methods, a thermocouple is placed in a precast concrete formwork, and the concrete filling state is discriminated by temperature change using the difference in specific heat between air and concrete. There are also things.
[0005]
[Problems to be solved by the invention]
By the way, the conventional concrete filling detection method has the following problems.
In other words, the potential between the electrodes installed in the precast concrete formwork is not constant due to the hardness of the water contained in the concrete and the influence of the ambient temperature. .
[0006]
In addition, in a case where the concrete filling state is detected using the difference in specific heat between air and concrete using a thermocouple, the concrete filling state cannot be detected accurately if the temperature difference between the concrete and the temperature is small. In particular, in a building buried in the ocean, the interior is filled with seawater, so detection by a temperature difference is difficult.
[0007]
Also, the difference between mortar and aggregated concrete cannot be identified. This is because the systems currently commercialized both detect filling using the chemical properties of mortar, and the difference between concrete and mortar is the presence or absence of aggregate. This is because it is impossible to distinguish between concrete and mortar unless it can be recognized.
[0008]
The present invention has been made in view of such circumstances, and accurately describes the filling state of a filler such as concrete in a predetermined space such as a closed space and an open space where filling cannot be easily confirmed by visual observation or the like. An object of the present invention is to provide a filling detection method and a filling detection apparatus that can be easily detected.
[0009]
[Means for solving the problems]
According to a first aspect of the present invention, there is provided a method for detecting a filling in a closed space, wherein an electrical signal whose frequency continuously changes in a predetermined range is applied to a sensor element that converts electrical energy into mechanical energy. Changes in the position and magnitude of the peak voltage in the frequency-voltage characteristics of the electrical signal applied to the sensor element according to changes in the vibration frequency characteristics when contacting with the filling material filled in the space Thus, the filling state of the filler in the space is detected , and a difference in physical properties of the concrete or mortar serving as the filler is detected .
[0010]
According to this method, the concrete that becomes the filler in the space is utilized by changing the frequency characteristics of vibration of the sensor element when the filler is brought into contact with the sensor element and when the filler is not brought into contact with the sensor element. Alternatively, the filling state of mortar is detected. This makes it possible to accurately and easily detect the filling state of concrete or mortar regardless of changes in ambient temperature. For example, when the filling material is concrete, the filling state can be accurately detected without being affected by the temperature, the temperature of the concrete, the hardness of water used, and the like.
[0011]
In addition, since the inherent vibration frequency characteristic of the sensor element is known in advance, it is not necessary to perform special operations such as setting a special reference value at the site, and the filling status can be detected in a short time. Furthermore, since the vibration frequency characteristics of the sensor element change depending on the specific gravity and viscosity of the substance in contact with the sensor element, observing the amount of change identifies whether the filled substance is concrete or mortar. Is possible.
[0012]
According to a second aspect of the present invention, there is provided a method for detecting a filling in a closed space, wherein a plurality of sensor elements for converting electrical energy into mechanical energy are arranged apart from each other, and an electric signal whose frequency continuously changes in a predetermined range is applied to each of the sensor elements. The peak voltage in the frequency-voltage characteristic of the electric signal applied to the sensor according to the change in the vibration frequency characteristic when the sensor element is brought into contact with the filling material filled in a predetermined space. By detecting a change in position and size, the filling state of the constituent material of the filling is detected, a difference in physical properties of the concrete or mortar that becomes the filling is detected, and any one of the sensor elements When the change different from the vibration frequency characteristic change of other sensor elements is detected, the filling is made of concrete .
[0013]
According to this method, since the same electrical signal is applied to each of the plurality of sensor elements to detect each change in vibration frequency characteristics, it is possible to detect the filling state of the constituent material of the filling. For example, when the filling material is concrete, the constituent materials are mortar and aggregate, and a difference appears between the change in the vibration frequency characteristic of the sensor element in contact with the mortar and the change in the vibration frequency characteristic of the sensor element in contact with the aggregate. At this time, when any one of the sensor elements detects a change different from the vibration frequency characteristic change of the other sensor elements, it can be known that the concrete has been filled, assuming that mortar and aggregate are mixed .
[0014]
According to a third aspect of the present invention, there is provided a filling detection apparatus that repeatedly generates a sensor element that converts electrical energy into mechanical energy and an electrical signal whose frequency continuously changes within a predetermined range, and the generated electrical signal is the sensor. A signal generating / applying means to be applied to the element; a frequency characteristic detecting means for detecting a vibration frequency characteristic of the sensor element when the electrical signal generated by the signal generating / applying means is applied to the sensor element; The frequency characteristic detection means when nothing is brought into contact with the sensor element from the change in the position and magnitude of the peak voltage in the frequency-voltage characteristic corresponding to the vibration frequency characteristic change of the sensor element, which is the output of the frequency characteristic detection means based on the output of it and the detection object with determining contact and non-contact of the detection object in a given space relative to the sensor element Characterized by comprising determination means for determining the difference of the physical properties of the concrete or mortar.
[0015]
According to this configuration, a sensor element (for example, a piezoelectric speaker) that converts an electrical signal into a mechanical signal is vibrated by a sine wave, and the frequency characteristic of the sensor element is changed by changing the frequency of the sine wave in an arbitrary range. Since the change in the position and magnitude of the peak voltage in the frequency-voltage characteristic according to the frequency is detected, the vibration frequency characteristic changes when the concrete or mortar filling comes into contact with the sensor element. possible to detect the filling situation in the Do Ri, also it can easily determine the difference in physical properties of the concrete or mortar.
[0018]
According to a fourth aspect of the present invention, there is provided a filling detection apparatus that repeatedly generates a plurality of sensor elements that convert electric energy into mechanical energy and an electric signal whose frequency continuously changes within a predetermined range. Signal generation / application means applied to each sensor element, and frequency characteristics for detecting vibration frequency characteristics of each sensor element when an electrical signal generated by the signal generation / application means is applied to each sensor element From the change in the position and magnitude of the peak voltage in the frequency-voltage characteristic according to the change in the vibration frequency characteristic of each sensor element that is the output of the detection means and the frequency characteristic detection means, nothing is brought into contact with each sensor element based on the output of the frequency characteristic detecting means when, with judges contact and non-contact of the detection object in a given space relative to the respective sensor element Serial comprising determination means for determining the difference of the sense target to become concrete or mortar properties, the determining means, the vibration frequency characteristic changes and different changes in any one any other sensor element of the sensor element When detected, the detection object is determined to be concrete .
[0019]
According to this configuration, the same electrical signal is applied to each of the plurality of sensor elements, and the change in the position and magnitude of the peak voltage in the frequency-voltage characteristic corresponding to each change in the vibration frequency characteristic is detected. It is possible to detect the filling state of the constituent material of the object. For example, when the filling material is concrete, the constituent materials are mortar and aggregate, and a difference appears between the change in the vibration frequency characteristic of the sensor element in contact with the mortar and the change in the vibration frequency characteristic of the sensor element in contact with the aggregate. At this time, when any one of the sensor elements detects a change different from the vibration frequency characteristic change of the other sensor elements, it can be known that the concrete has been filled, assuming that mortar and aggregate are mixed .
[0022]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a filling detection apparatus according to an embodiment of the present invention.
[0023]
In this figure, the filling detector according to the present embodiment includes a synchronization signal generator 1, a variable frequency oscillator 2, an amplifier 3, a piezoelectric speaker (sensor element) 4, a resistor 5, and a differential amplifier 6. A quadrant multiplier 7, a low-pass filter 8, and a determination unit 9.
[0024]
The synchronization signal generator 1 generates a synchronization signal for repeatedly operating the variable frequency oscillator 2. The variable frequency oscillator 2 generates a sinusoidal electric signal whose frequency continuously changes in a predetermined frequency range (for example, 1 kHz to 20 kHz). In this case, every time a synchronization signal is output from the synchronization signal generator 1, a sine wave signal is repeatedly generated from an initial frequency (for example, 1 kHz). The amplifier 3 amplifies the sine wave signal from the variable frequency oscillator 2 to a level at which the piezoelectric speaker 4 can be driven, and outputs it as an excitation signal Vr. In the present embodiment, the synchronous signal generator 1, the variable frequency oscillator 2, and the amplifier 3 are collectively referred to as signal generation / application means.
[0025]
The piezoelectric speaker 4 uses a piezoelectric element, and converts an electrical signal into a mechanical signal and outputs it. The resistor 5 is inserted in series between the amplifier 3 and the piezoelectric speaker 4, and a voltage corresponding to the current flowing through the piezoelectric speaker 4 is generated at both ends thereof. Since the current flowing through the piezoelectric speaker 4 changes according to the change in frequency, the voltage appearing at both ends of the resistor 5 reflects the frequency characteristics of the piezoelectric speaker 4.
[0026]
The differential amplifier 6 amplifies the voltage across the resistor 5 and outputs a voltage Vi. The 4-quadrant multiplier 7 multiplies the excitation signal Vr and the voltage Vi to remove the influence of noise on these voltages. The low-pass filter 8 outputs a signal (output voltage Vo) obtained by removing cos (2ωt + α + β) described below from the output signal of the 4-quadrant multiplier 7. In this embodiment, the resistor 5, the differential amplifier 6, the four-quadrant multiplier 7, and the low-pass filter 8 are collectively referred to as frequency characteristic detecting means.
[0027]
The determination unit 9 includes a display such as a microcomputer or LCD (liquid crystal display) (not shown), and is output from the low-pass filter 8 on the basis of the characteristic vibration frequency characteristic when the concrete is not brought into contact with the piezoelectric speaker 4. The contact / non-contact of the concrete in the precast concrete mold with respect to the piezoelectric speaker 4 is determined from the signal, and the result (good or bad) is displayed on the display. In this case, once the unique vibration frequency characteristics of the piezoelectric speaker 4 are set, there is no need to reset them except during maintenance. The inherent vibration frequency characteristic of the piezoelectric speaker 4 is stored in the memory of the microcomputer.
[0028]
In such a configuration, the sine wave signal generated by the variable frequency oscillator 2 is amplified by the amplifier 3 and input to the piezoelectric speaker 4 as the excitation voltage Vr, and mechanical vibration is generated in the piezoelectric speaker 4. To do. The excitation voltage Vr is also input to the 4-quadrant multiplier 7. When mechanical vibration is generated in the piezoelectric speaker 4, a voltage corresponding to the current flowing through the piezoelectric speaker 4 is generated at both ends of the resistor 5. This voltage is amplified by the differential amplifier 6 to output the voltage Vi. The four-quadrant multiplier 7 multiplies the voltage Vi and the excitation voltage Vr from the amplifier 3. Then, the output is obtained as an output voltage Vo by removing the cos (2ωt + α + β) component by the low-pass filter 8.
[0029]
The output signal Vo is a signal reflecting the frequency characteristics (amplitude and phase) of the piezoelectric speaker 4 with respect to the frequency change of the excitation signal. At this time, if nothing is in contact with the surface of the piezoelectric speaker 4, a voltage having a peak at a frequency near the natural frequency of the piezoelectric speaker 4 appears as shown in FIG. When concrete is filled around the piezoelectric speaker 4, the vibration characteristics of the piezoelectric speaker 4 change, and the position and magnitude of the peak voltage change as shown in FIG. The determination unit 9 determines the concrete filling state from the change in the peak voltage, and displays the result on the display. Thereby, it is possible to easily determine whether the concrete is filled.
[0030]
The operation principle will be described using mathematical expressions as follows.
Here, it is assumed that Vr = Asin (ωt + α) and Vi = Bsin (ωt + β). However, A and B are amplitudes, ωt is a frequency, and α and β are phase shifts.
Vr × Vi = Asin (ωt + α) × Bsin (ωt + β)
= AB [cos (β-α) -cos (2ωt + α + β)] / 2 (1)
[0031]
The part of cos (β−α) in the equation (1) is a direct current component that changes in accordance with the phase difference, and includes the amplitude component of the voltage Vi. The portion of cos (2ωt + α + β) is a signal having a frequency twice that of the original excitation voltage Vr and voltage Vi. Since the necessary frequency characteristic information is the amplitude (magnitude) of the voltage Vi, only cos (β−α) in the equation (1) is sufficient. Therefore, the component of cos (2ωt + α + β) may be removed by passing through the low-pass filter 8. In this way, frequency characteristics appear in the form of voltage in the output voltage Vo.
[0032]
As shown in FIGS. 2 and 3, when concrete is filled in a space such as a precast concrete formwork, the situation can be detected by changing the peak frequency and level.
[0033]
As described above, according to the present embodiment, a sine wave electric signal whose frequency continuously changes within a predetermined range is generated, and this electric signal is applied to the piezoelectric speaker 4 to detect the vibration frequency characteristic. Based on this vibration frequency characteristic, since the change of the frequency characteristic when the piezoelectric speaker 4 is brought into contact with the concrete filled in the precast concrete mold is detected, the temperature, the concrete temperature, the water used It is possible to detect the filling state of the concrete in the precast concrete formwork without being affected by the hardness of the steel. That is, it becomes possible to accurately and easily detect the concrete filling state in the precast concrete formwork.
[0034]
By the way, in the case of ordinary concrete, mortar (comprising cement, sand and water) and coarse aggregate are sufficiently mixed with a concrete mixer and then filled into a precast concrete formwork. It is conceivable that the material is caught by the reinforcing bar and only the mortar is filled. In this case, since there is a concern about insufficient strength of the concrete, a method that can reliably recognize the presence or absence of coarse aggregate is desired.
[0035]
Normally, when the coarse aggregate is in contact with the piezoelectric speaker 4 that is a sensor element, a flat waveform having almost no peak voltage as shown in FIG. 3 is obtained, but when the coarse speaker is in contact with a mortar without coarse aggregate. As shown in FIG. 4, the peak voltage shifts to the low frequency region, and its value also decreases.
[0036]
The problem here is that, when the piezoelectric speaker 4 is downsized, when the piezoelectric speaker 4 is installed at a location where concrete filling is to be detected and the concrete is filled, the piezoelectric speaker 4 as shown in FIG. If the coarse aggregate 30 does not come into contact, the waveform as shown in FIG. 4 is obtained, and the filled one is recognized as the mortar 31. On the other hand, as shown in FIG. 6, if the coarse aggregate 30 is in contact with the piezoelectric element 4, the waveform is as shown in FIG. 3, and it can be recognized that the concrete is filled. 5 and 6, the member indicated by reference numeral 32 is a control panel.
[0037]
If the piezoelectric speaker 4 itself is made larger, the proportion of contact with the coarse aggregate 30 increases, but the mass of the piezoelectric speaker 4 also increases and it becomes difficult to vibrate. In this case, the sensitivity of the piezoelectric speaker 4 deteriorates. The speaker 4 cannot be enlarged. Therefore, even if the piezoelectric speakers 4 are reduced in size, increasing the number thereof can increase the probability of contact with the coarse aggregate 30 and can be expected to improve the determination accuracy. Below, embodiment which can detect a filling condition by detecting the presence or absence of the coarse aggregate 30 which is a constituent material of concrete is described.
[0038]
FIG. 7 is a block diagram showing a configuration of a filling material detection apparatus according to another embodiment of the present invention.
In this figure, the filling material detection apparatus according to the present embodiment includes an excitation signal generation / application unit 20, a plurality of frequency characteristic detection units 21, and a determination unit 22. The excitation signal generation / application unit 20 includes the same components as the frequency signal generator 1, variable frequency oscillator 2 and amplifier 3 of the filler detection apparatus according to the first embodiment, and the frequency is in a predetermined frequency range. A sine wave electric signal that continuously changes at a frequency (for example, 1 kHz to 20 kHz) is generated.
[0039]
Each of the plurality of frequency characteristic detection units 21 includes the same ones as the piezoelectric speaker 4, the resistor 5, the differential amplifier 6, the four quadrant multiplier 7, and the LPF 8 of the filling detection device according to the first embodiment. The vibration frequency characteristic of the speaker 4 is detected. The determination unit 22 detects mortar and coarse aggregate, which are constituent materials of concrete, from the detection results of the frequency characteristic detection units 21. As shown in FIG. 8, the piezoelectric speakers 4 of each frequency characteristic detection unit 21 are arranged adjacent to each other on the plate 23 at regular intervals. In this figure, nine piezoelectric speakers 4 are arranged. The plurality of piezoelectric speakers 4 and the plate 23 that fixes them are referred to as sensor portions.
[0040]
The determination unit 22 detects each vibration frequency characteristic change when the sensor unit is brought into contact with the concrete in the precast concrete mold, based on the output of each frequency characteristic detection unit 21 when nothing is brought into contact with the sensor unit. By doing so, it is determined whether the filling is concrete or mortar. That is, if the vibration frequency characteristic change of all the piezoelectric speakers 4 in the sensor section is as shown in FIG. 4, it is determined that the mortar has no coarse aggregate, and any one of all the piezoelectric speakers 4 has the vibration frequency characteristic change of FIG. If so, it is determined as concrete. When it is determined that the mortar is used even though the concrete is used as the filler, it can be determined that the coarse aggregate is caught by the reinforcing bar due to overfilling or the like and only the mortar is filled. Moreover, when it determines with concrete, it can be judged that concrete was filled correctly.
[0041]
Here, FIG. 9 is a diagram showing an example of a filling state when the sensor unit is used. Since the piezoelectric speaker 4-1 is in contact with the coarse aggregate 30, all the remaining piezoelectric speakers 30 are coarse. Even if it is not in contact with the aggregate 30, it can be seen that the concrete is filled. Note that the greater the number of piezoelectric speakers 4 and the smaller the interval, the higher the probability of contact with the coarse aggregate 30 in the concrete and the determination accuracy improves. However, since the size is actually limited, The number and spacing should be in accordance with the proportion of concrete coarse aggregate used. Generally used coarse aggregate has a maximum dimension of 20 or 25 mm, and the porosity (part not coarse aggregate ≒ mortar + fine aggregate) is generally 30-40%. It is good to make it a dimension.
[0042]
As described above, according to the present embodiment, the same electrical signal is applied to each of the plurality of piezoelectric speakers 4 to detect the respective vibration frequency characteristic changes. Therefore, the mortar and the coarse aggregate that are the constituent materials of the concrete are detected. The filling situation can be detected.
[0043]
In each of the above embodiments, a sine wave having a single frequency range is used. However, a frequency range switch (not shown) for switching the frequency range is provided, and a sine wave having a plurality of frequency ranges is alternatively selected. You may make it selectable. In this case, the variable frequency oscillator 2 has a function of repeatedly generating a sine wave signal in the frequency band in the range switched by the frequency range switch. In this way, by selecting sine waves in multiple frequency ranges, the optimum frequency range for measurement can be selected according to the physical characteristics such as the structure and material of the precast concrete formwork. This allows for more accurate measurements.
[0044]
In each of the above embodiments, the determination units 9 and 22 are provided. However, it is not always necessary to provide them, and the output waveform of the low-pass filter 8 may be observed using a waveform measurement device such as an oscilloscope. good. When there is a waveform measuring device such as an oscilloscope, the cost of the device can be reduced by the amount that the determination units 9 and 22 are unnecessary.
[0045]
In each of the above embodiments, detection of the state of filling in a closed space such as a precast concrete formwork of concrete has been described. However, the state of filling into a formwork made of other wooden formwork or steel material is described. Needless to say, it can be used for detection and the like.
[0046]
【The invention's effect】
According to the method for detecting a filling in a closed space according to the first aspect of the present invention, a sine wave electric signal whose frequency continuously changes within a predetermined range is generated, and this electric signal is converted into mechanical energy. Applied to the element to be converted to detect the frequency characteristic of the vibration of the element, and based on this frequency characteristic, the change of the frequency characteristic when the element is brought into contact with the filler filled in the space is detected. Therefore, the filling situation in the space of the filling can be detected accurately and easily.
[0047]
According to the method for detecting a filler in a closed space according to the second aspect of the present invention, the same electrical signal is applied to each of the plurality of sensor elements to detect each change in vibration frequency characteristics. The filling situation can be detected.
[0048]
According to the filling detector of the invention of claim 3, a sensor element (for example, a piezoelectric speaker) that converts an electrical signal into a mechanical signal is vibrated by a sine wave, and the frequency of the sine wave is changed within an arbitrary range. Since the vibration frequency characteristic of the sensor element is detected by this, the filling state in the space of the filler can be detected by the change of the vibration frequency characteristic when the filler such as concrete contacts the sensor element. .
[0049]
According to the filler detection device of the invention of claim 3 , it is possible to easily determine whether or not a filler such as concrete is in contact with the sensor element, based on the output of the determination means.
[0050]
According to the packing detection device of the invention according to claim 4 , since the same electrical signal is applied to each of the plurality of sensor elements to detect the change in the vibration frequency characteristics, the filling status of the constituent material of the packing is determined. Can be detected.
[0051]
According to the filler detection device of the invention of claim 5 , since the piezoelectric speaker is used as the sensor element, an inexpensive filler detection device can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a filling material detection apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of a measurement result obtained by the filling detection apparatus of FIG. 1, and is an output voltage waveform diagram when there is no concrete in a precast concrete formwork.
FIG. 3 is a diagram illustrating an example of a measurement result obtained by the filling detection apparatus of FIG. 1, and is an output voltage waveform diagram when concrete is present in a precast concrete formwork.
FIG. 4 is a diagram showing an example of a measurement result obtained by the filling detection apparatus of FIG. 1, and is an output voltage waveform diagram when mortar is present in a precast concrete formwork.
FIG. 5 is a diagram showing a concrete filling state in a precast concrete formwork, and is a diagram in a case where a coarse aggregate is not in contact with a piezoelectric speaker.
FIG. 6 is a diagram showing a concrete filling state in a precast concrete formwork, and is a diagram in a case where a coarse aggregate is in contact with a piezoelectric speaker.
FIG. 7 is a block diagram showing a configuration of a filling detection device according to another embodiment of the present invention.
FIG. 8 is a diagram showing a sensor unit of the filling material detection apparatus of FIG. 7;
FIG. 9 is a view showing a state of filling concrete in a precast concrete formwork, and is a view in a case where coarse aggregate is in contact with one piezoelectric speaker of a sensor unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Synchronous signal generator 2 Variable frequency oscillator 3 Amplifier 4, 4-1, 4-2, 4-3 Piezoelectric speaker 5 Resistance 6 Differential amplifier 7 4 Quadrant multiplier 8 Low pass filter 9, 22 Judgment part 20 Excitation signal Generation and application unit 21 Frequency characteristic detection unit 30 Coarse aggregate 31 Mortar 32 Control panel

Claims (4)

When an electric signal whose frequency continuously changes in a predetermined range is applied to a sensor element that converts electrical energy into mechanical energy, and the sensor element is brought into contact with a filler filled in a predetermined space, the vibration of the sensor element By detecting a change in the position and magnitude of the peak voltage in the frequency-voltage characteristic of the electrical signal applied to the sensor element according to the frequency characteristic change, the filling state of the filler in the space is detected. A filler detection method characterized by detecting a difference in physical properties of the concrete or mortar that is the filler. A plurality of sensor elements that convert electrical energy into mechanical energy are arranged apart from each other, and an electric signal whose frequency continuously changes in a predetermined range is applied to each sensor element, and each sensor element is filled in a predetermined space. By detecting the change in the position and magnitude of the peak voltage in the frequency-voltage characteristic of the electrical signal applied to the sensor according to the change in the vibration frequency characteristic when the object is brought into contact with the object, Detects the filling status of the constituent materials, detects the difference in the physical properties of the concrete or mortar that becomes the filler, and detects any change that differs from the vibration frequency characteristics of other sensor elements. When it does, the said filling material is made into concrete, The packing detection method characterized by the above-mentioned . A sensor element for converting electrical energy into mechanical energy;
A signal generating / applying means for repeatedly generating an electric signal whose frequency continuously changes in a predetermined range and applying the generated electric signal to the sensor element;
A frequency characteristic detecting means for detecting a vibration frequency characteristic of the sensor element when the electric signal generated by the signal generating / applying means is applied to the sensor element;
The frequency characteristic detection when nothing is brought into contact with the sensor element from the change in the position and magnitude of the peak voltage in the frequency-voltage characteristic corresponding to the vibration frequency characteristic change of the sensor element, which is the output of the frequency characteristic detection means And determining means for determining the contact / non-contact of the object to be detected in a predetermined space with respect to the sensor element and determining the difference in physical properties of the concrete or mortar serving as the object to be detected based on the output of the means. A filling detector. A plurality of sensor elements for converting electrical energy into mechanical energy;
A signal generating / applying means for repeatedly generating an electric signal whose frequency continuously changes in a predetermined range and applying the generated electric signal to each sensor element;
A frequency characteristic detecting means for detecting a vibration frequency characteristic of each sensor element when the electric signal generated by the signal generating / applying means is applied to each sensor element;
The frequency when nothing is brought into contact with each sensor element from the change in the position and magnitude of the peak voltage in the frequency-voltage characteristic corresponding to the change in the vibration frequency characteristic of each sensor element that is the output of the frequency characteristic detecting means Determination means for determining contact / non-contact of a detection object in a predetermined space with respect to each sensor element with reference to an output of the characteristic detection means and determining a difference in physical properties of the concrete or mortar serving as the detection object equipped with,
The determination unit determines that the detection object is concrete when any one of the sensor elements detects a change different from the change in vibration frequency characteristics of the other sensor elements. .

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