KR102088358B1 - Method for controlling frequency of scale-removal apparatus and scale-removal apparatus thereof - Google Patents

Abstract

The present invention relates to a method of controlling an apparatus for removing scale by using a cavitation generated by the ultrasonic wave, wherein the apparatus comprises: an oscillator unit which outputs an electric signal; and an ultrasonic wave generation unit which changes an output signal of the oscillator unit into a physical vibration to generate an ultrasonic wave. According to the present invention, the controlling method may comprise the steps of: dividing a concerned frequency area, which is a frequency area where a frequency sweep is performed, into a plurality of subareas; performing, in each of the divided subareas, the frequency sweep at a first sweep interval which is greater than the minimum sweep interval and thus acquiring amplitude sizes of the ultrasonic wave generated by the ultrasonic wave generation unit; determining the ranking of an average amplitude size between the subareas based on the amplitude sizes of the acquired ultrasonic wave; determining the ranking in maintaining a high point in accordance with the result of adding the average amplitude size of each of the plurality of subareas and the average amplitude size of at least one subarea adjacent to each of a plurality of subsections, for each of the plurality of subareas; and determining the frequency sweep sequence among the plurality of subsections based on the determined ranking of the average amplitude size and the determined ranking in maintaining a high point.

Description

Method for controlling frequency of scale removing device and scale removing device using same {Method for controlling frequency of scale-removal apparatus and scale-removal apparatus thereof}

The present disclosure relates to a method for adjusting the frequency of a scale removing device and a scale removing device using the same, more specifically, by converting an electrical signal into ultrasonic energy and adjusting the frequency of a device for removing the scale using sound pressure of ultrasonic waves. The invention relates to a method for removing a scale and an apparatus using the same.

In a boiler or a heat exchange system, debris or various organic substances may be deposited inside the pipe through which the fluid flows. At this time, it is possible to remove the organic material deposited by using a chemical substance, but there is a problem that a substance harmful to the human body may be generated due to the chemical substance.

Therefore, as an alternative to chemical treatment, a physical scale removal method using ultrasound is required. At this time, when the frequency of the ultrasonic wave coincides with the resonant frequency of the target object to remove the scale, high energy ultrasonic waves are generated to effectively remove the scale.

Even if the output signal frequency of the oscillation unit included in the descaling unit is adjusted once to generate resonance, the resonance frequency may be changed after the scale is deposited or the object to remove the scale is aged. Accordingly, there is a need for a method of efficiently adjusting the frequency of the oscillation unit in order to generate ultrasonic waves matching the resonance frequency.

It is to provide a method for adjusting the frequency of a scale removing device and a scale removing device using the same. The technical problems to be achieved by the present embodiment are not limited to the technical problems as described above, and other technical problems may be inferred from the following embodiments.

According to an aspect, an oscillation unit for outputting an electrical signal and an ultrasonic generator for generating ultrasonic waves by changing the output signal of the oscillation unit into physical vibrations, and removing scale by using cavitation generated by ultrasonic waves The control method of the apparatus includes dividing a frequency region of interest, which is a frequency domain in which frequency-sweep is performed, into a plurality of sub-regions, and in each of the divided sub-regions, between adjacent frequencies distinguished by the apparatus. Acquiring amplitude magnitudes and frequencies of the ultrasonic waves generated by the ultrasonic generator as the frequency-sweep is performed at a first sweep interval greater than the minimum sweep interval, which is the minimum frequency interval, based on the amplitude amplitudes of the obtained ultrasonic waves Thus, determining the rank of the average amplitude size between the sub-regions, the average true of each of the plurality of sub-regions Determining, for each of the plurality of sub-regions, a high-point maintenance ranking determined according to a sum of the magnitude and the average amplitude magnitude of at least one sub-region adjacent to each of the plurality of sub-regions, and Determining a frequency-swept order between a plurality of sub-regions, based on the weighted sum of the ranking and the determined high-potential maintenance ranking, in a sequence of any randomly determined first sweep interval within the sub-region of the highest ranking The three sweep frequencies are called f1, f2, and f3 (where f1 <f2 <f3), and the amplitudes of ultrasonic waves at each of the three sweep frequencies are called I_u1, I_u2, and I_u3, and each of the three sweep frequencies When the frequencies of the ultrasonic waves are called f_u1, f_u2, and f_u3, determining whether they satisfy a condition including a resonance frequency satisfying Equation 1 below, and

-Equation 1-

Upon determining that the conditions for resonant frequency inclusion are met, the step of performing frequency-swept with a minimum sweep interval for the frequency domains f1 to f3 may be included.

According to another aspect, the scale removing device includes an oscillation unit that outputs an electrical signal, an ultrasonic generator that generates ultrasonic waves by changing the output signal of the oscillation unit into physical vibration, and includes amplitude and frequency information of ultrasonic waves sensed by detecting ultrasonic waves. An ultrasonic sensing unit for outputting an electrical signal, and a processor for performing frequency-sweeping on the output signal of the oscillation unit by using the output signal of the ultrasonic sensing unit, the processor is a frequency domain of interest, which is a frequency domain in which frequency-sweeping is performed. Is divided into a plurality of sub-regions, and in each of the divided sub-regions, amplitude magnitudes of ultrasonic waves generated by the ultrasonic generator are obtained by performing frequency-swept with a first sweep interval greater than a minimum sweep interval, Based on the amplitude amplitudes of the acquired ultrasound waves, rank the average amplitude magnitudes among the sub-regions. A high-point maintenance rank determined according to a sum result of the average amplitude size of each of the plurality of sub-regions and the average amplitude size of at least one sub-region adjacent to each of the plurality of sub-regions, to each of the plurality of sub-regions The frequency-swept order between the plurality of sub-regions, and based on the determined order, based on the determined average amplitude magnitude ranking and the determined high-spotness ranking, at a first sweep interval in the best-ranked sub-region. The determined consecutive three sweep frequencies are called f1, f2, and f3 (where f1 <f2 <f3), and the amplitudes of ultrasonic waves at each of the three sweep frequencies are called I_u1, I_u2, and I_u3, and 3 When the frequencies of the ultrasonic waves at each of the sweep frequencies are f_u1, f_u2, and f_u3, it is determined whether or not a condition including a resonance frequency satisfying Equation 2 is satisfied.

-Equation 2-

As it is determined that the conditions for resonant frequency inclusion are met, frequency-swept may be performed in a frequency range from f1 to f3 with a minimum sweep interval.

1 is a diagram schematically illustrating a method for removing scale according to an embodiment.
2 is a view for explaining the relationship between the frequency and the amplitude of the output signal of the oscillation unit, the ultrasonic generation unit, and ultrasonic waves according to an embodiment.
3 is a flowchart illustrating a scale removing method performed by an apparatus for removing scale according to an embodiment.
4 is a block diagram of an apparatus for removing a scale according to an embodiment.
5 and 6 are diagrams for describing an algorithm for determining a sweep order of sub-regions.
7 is a view for explaining a method of adjusting the sweep interval within each sub-region.
8 is a flowchart of a frequency sweep method performed by a scale removing device according to another embodiment.

The terminology used in the present embodiments has been selected from the general terms that are currently widely used as possible while considering the functions in the present embodiments, but this may vary depending on the intention or precedent of a person skilled in the art or the appearance of new technology. Also, in certain cases, some terms are arbitrarily selected by the applicant, and in this case, their meanings will be described in detail in the corresponding parts. Therefore, the terms used in the present embodiments should be defined based on the meanings of the terms and the contents of the present embodiments, not simply the names of the terms.

Throughout the specification, when a part is connected to another part, this includes not only the case of being directly connected, but also the case of being electrically connected with another element in between. Also, when a part includes a certain component, this means that other components may be further included rather than excluding other components unless otherwise specified. In addition, the terms of the components described in the present exemplary embodiments mean a unit for processing at least one function or operation, which may be implemented in hardware or software, or a combination of hardware and software.

1 is a diagram schematically illustrating a method for removing scale according to an embodiment.

The oscillation unit may output an electrical signal. At this time, the oscillation unit may output an electrical signal having a frequency determined based on the target ultrasound frequency.

For example, the oscillation unit may output a pulse wave signal in a pulse width modulation (PWM) method, and at this time, the frequency of the output signal may be output for 1 second to indicate the number of transmitted pulses.

At this time, the ultrasonic generator and the oscillation unit may be connected by a connection unit having a predetermined physical structure. Through the connection portion, the oscillation portion can be protected by allowing only the ultrasonic generator to vibrate in a fixed state.

The electrical signal output from the oscillation unit may be applied to the ultrasonic generator. The ultrasonic generator may convert, for example, an electrical signal applied from the oscillation unit into a physical signal. For example, the ultrasonic generator may be physically deformed upon receiving an electrical signal. At this time, the physical deformation pattern of the ultrasonic generator may be determined according to the frequency and amplitude of the applied electrical signal. For example, the ultrasonic generator may physically vibrate to correspond to the frequency and amplitude of the applied electrical signal. Also, as the ultrasonic generator physically vibrates, ultrasonic pressure may be generated by changing the pressure of the surrounding air.

At this time, the electrical signal output from the oscillation unit is amplified through an amplifier, and the amplified electrical signal can be applied to the ultrasonic generator.

For example, the ultrasonic generator may include a magnetostrictive element. The magnetostrictive element may physically vibrate due to a change in magnetic properties caused by the application of an electrical signal, for example, a pulse wave signal or an alternating current signal.

The ultrasonic generator may include a guide for transmitting the physical vibration of the magnetostrictive element to an external heat treatment tube. For example, one end of the guide may be combined by a magnetostrictive element and a brazing method such as brazing. In addition, the other end of the guide is welded to the outside of the heat treatment tube or the like to be cleaned, and the physical vibration generated from the magnetostrictive element is transmitted to the heat treatment tube through the guide, so that ultrasonic waves proceeding to the inside and outside of the heat treatment tube can be generated. have.

The ultrasonic sensing unit may be physically deformed due to sound pressure of ultrasonic waves. At this time, the deformation pattern of the ultrasonic sensor may be determined according to the ultrasonic frequency and the intensity of ultrasonic waves. Also, the ultrasonic sensing unit may output an electrical signal corresponding to physical deformation. For example, the ultrasonic sensing unit may output an electrical signal including frequency information of the ultrasonic sensing unit and intensity information of the ultrasonic. For example, the ultrasonic sensor may be implemented as a thin film piezoelectric element, but is not limited thereto.

Ultrasound passes through the liquid medium in the boiler tube and causes a local change in the temperature and pressure of the liquid medium. As a result, the liquid medium is disturbed and a cavity, ie, cavitation, is created inside the liquid.

At this time, debris (scale) attached to the boiler tube is removed due to pressure and heat generated as the generated cavitation collapses.

2 is a view for explaining the relationship between the frequency and the amplitude of the output signal of the oscillation unit, the ultrasonic generation unit, and ultrasonic waves according to an embodiment.

Referring to FIG. 2, the output signal of the oscillation unit, the vibration of the ultrasonic generation unit, and the time waveform of the ultrasonic waves are sequentially shown from the top.

The output signal of the oscillation unit is a pulse wave signal, the period is Te, and the frequency is represented by fe (= 1 / Te). In actual implementation, it may represent a part of a distorted signal, not a perfect pulse wave, and various other signals may be generated.

Further, referring to the time waveform for the vibration of the ultrasonic generator, the period is Tm, and the frequency is fm (= 1 / Tm) as a sinusoidal wave. At this time, the vibration period (frequency) of the ultrasonic generator may be determined based on the period (frequency) of the pulse wave signal. For example, it may be the same as the vibration period (frequency) of the ultrasonic generator.

Similarly, referring to the time waveform for the vibration of the ultrasonic generator, the period is Tu as a sinusoidal wave, and the frequency is represented by fu (= 1 / Tu). The period (frequency) of the ultrasonic wave may be the same as the period (frequency) of the signal of the pulse wave or the vibration period (frequency) of the ultrasonic generator or the vibration period (frequency) of the ultrasonic generator.

In FIG. 2, the time waveform of the ultrasonic vibration unit and the time waveform of the ultrasonic wave are shown as sinusoidal waves, but may have various forms according to noise or frequency characteristics. The sinusoidal wave illustrated in FIG. 2 represents a sinusoidal wave having a maximum amplitude frequency having a maximum frequency component, and the frequencies of the three waveforms illustrated in FIG. 2 may be theoretically the same, but a difference may occur due to various factors.

In addition, a time delay may be generated at each conversion in the process in which the pulse wave is converted into vibration of the ultrasonic generator and ultrasonic waves are generated therefrom.

3 is a flowchart illustrating a scale removing method performed by an apparatus for removing scale according to an embodiment.

The method described with reference to FIG. 3 includes an oscillation unit that outputs an electrical signal and an ultrasonic generation unit that generates ultrasonic waves by changing the output signal of the oscillation unit into physical vibration, and removes the scale using cavitation generated by ultrasonic waves. Can be performed by.

The characteristics such as the amplitude and / or the frequency of the ultrasonic wave generated by converting the electrical signal output from the oscillating portion into physical vibration are referred to as "frequency response characteristics" with respect to the frequency of the output signal of the oscillating portion or the input signal applied from the oscillating portion.

Frequency-sweep refers to changing the frequency to a predetermined frequency difference and analyzing the frequency response to it. At this time, a plurality of sweep frequencies may be defined. Through frequency-sweep, analysis of the frequency response for each of the sweep frequencies is performed.

At this time, the frequency difference between adjacent sweep frequencies is called a sweep interval. The narrower the sweep interval, the more frequency-swept can be obtained to obtain a highly reliable frequency response analysis result, but the time spent on it increases.

The frequency range (region) or the frequency-swept region of interest is the entire region in which the sweep is performed, and may be preset according to the purpose of the frequency-swept. For example, when analyzing the amplitude and frequency of ultrasound generated from an electrical signal, considering the correlation between the frequency of the ultrasound and the electrical signal,

As the frequency band of interest and the sweep interval are determined, a plurality of sweep frequencies at which frequency-sweep is performed may be determined. In this case, if the relationship between two different sweep frequencies is defined, a relatively small frequency of the two sweep frequencies is defined as a leading frequency for another frequency, whereas a relatively large frequency is a trailing frequency for another frequency. Define.

Also, a frequency adjacent to a sweep frequency represents a frequency that is greater or less than the sweep frequency by a sweep interval. In addition, m adjacent frequencies represent m different frequencies determined in the order in which the difference from the corresponding sweep frequency is small.

In operation 310, the apparatus may divide a frequency region of interest, which is a frequency region in which frequency-sweeping is performed on the output signal of the oscillation unit, into a plurality of sub-regions.

As described above, the frequency domain of interest represents a frequency domain defined by a predetermined lower limit frequency and an upper limit frequency in performing frequency-sweeping on the output signal of the oscillation unit. The frequency region of interest may be, for example, a frequency section in which the lower limit is 15 kHz and the upper limit is 28 kHz, but is not limited thereto, and may be determined in various ranges according to the structure and type of the scale removal target.

The apparatus may divide the determined frequency region of interest into a plurality of sub-regions. For example, the device may divide the frequency region of interest into a plurality of sub-regions having the same section length. The number of sub-regions can be variously determined. For example, as the number of sub-regions increases, the reliability of the sweep order between sub-regions may increase as described below, but the time spent on this may increase.

For example, the section length of each of the sub-regions may be determined by a predetermined multiple of the predicted value of the bandwidth of the resonant frequency according to the amplitude characteristic of the ultrasound according to the frequency. At this time, as the number of frequency domains increases, that is, as the interval length of each of the sub-regions decreases, the weight for the rank of the average amplitude magnitude increases as described below, and the The weight can be reduced.

In step 320, the device acquires amplitude amplitudes of the ultrasonic waves generated by the ultrasonic generator at each sweep frequency, while performing frequency-swept in each of the divided sub-regions at a first sweep interval greater than a minimum sweep interval. can do.

The device may sweep the frequency of the output signal of the oscillation unit in a plurality of sub-regions, at a first sweep interval greater than a minimum sweep interval.

In addition, as the device sweeps the frequency, the amplitude of the ultrasonic wave corresponding to the frequency of the output signal can be obtained. Accordingly, the apparatus may acquire each of amplitude amplitudes of ultrasonic waves generated from the output signal, for each of the plurality of sweep frequencies determined by sweeping the frequency at the first sweep interval in the sub-region.

The first sweep interval may correspond to a predetermined multiple of the minimum sweep interval. In determining the characteristics of each of the plurality of sub-regions within the frequency domain of interest, the first sweep interval determines precision. The first sweep interval may be determined based on a previously performed sample experiment result or simulation result.

In operation 330, the apparatus may determine a ranking of the average amplitude magnitude between sub-regions based on the amplitude magnitudes of the acquired ultrasound waves.

The device may acquire the magnitude of the average amplitude of ultrasonic waves for each sub-region. At this time, the apparatus may calculate the magnitude of the average amplitude of the ultrasound using only amplitude magnitudes of the ultrasound having a magnitude equal to or greater than a predetermined threshold amplitude. At this time, the amplitude of the ultrasound may indicate the amplitude of the ultrasound corresponding to the maximum frequency component constituting the ultrasound obtained through frequency domain analysis. Alternatively, the amplitude size of the ultrasound may indicate the frequency of the oscillation unit, that is, the amplitude of the ultrasound corresponding to the frequency component of each sweep frequency. However, in addition to this, the amplitude of the ultrasonic waves for calculating the average amplitude size of the ultrasonic waves may be processed in various ways.

The apparatus may determine the rank of the average amplitude size by comparing the average amplitude size calculated for each of the plurality of sub-regions. At this time, in order to determine the rank of the average amplitude size, the device may quantize the average amplitude size according to a predetermined quantization interval. This is to reduce the effect of small differences caused by noise or errors on the results.

In step 340, the apparatus determines a high-point maintenance ranking determined according to the size of a sum result of the average amplitude size of each of the plurality of sub-regions and the average amplitude size of at least one sub-region adjacent to each of the plurality of sub-regions, the plurality of It can be determined for each of the sub-regions.

At this time, the fact that the two sub-regions are adjacent may indicate that the upper limit of one sub-region of the two sub-regions is the same as the lower limit of the other sub-regions. Alternatively, k adjacent sub-regions adjacent to one sub-region indicate k sub-interesting frequency regions determined in a small order of distance from one sub-region among sub-regions other than one sub-region.

The high-maintenance ranking may be determined based on the average amplitude size of each of the plurality of sub-regions and the average amplitude size of at least one adjacent sub-region. The high-maintenance ranking of one sub-region is the average amplitude size of the sub-frequency region adjacent to the lower limit of the day sub-swept-frequency, the average amplitude magnitude of the day sub-region, and the average amplitude of the sub-region adjacent to the upper limit of the day sub-region. It can be determined based on the average of the sizes. At this time, the rank of the average amplitude size may be used instead of the average amplitude size. If the lower limit or upper limit of the sub-area is equal to the lower or upper limit of the entire frequency domain of interest, respectively, if it is the first sub-region containing the smallest sweep-frequency or the last sub-region containing the largest sweep-frequency, the corresponding interval, respectively The high-maintenance ranking may be determined using an average amplitude size or a rank of the average amplitude size of at least one sub-region adjacent to the upper or lower limit of.

In operation 350, the apparatus may determine a frequency-swept order between the plurality of sub-intervals based on the determined rank of the average amplitude magnitude and the determined rank of the highest peak retention.

The device may determine weights for each of the determined average amplitude magnitude ranking and the determined high peak maintenance ranking. For example, the weight of the rank of the average amplitude size may decrease as the number of the plurality of sub-regions is small. In addition, the weight of the high-point maintenance rank may decrease as the number of the plurality of sub-regions is small. At this time, the rank may be inversely proportional to the magnitude of the amplitude of the corresponding sweep-frequency sub-section and / or adjacent sweep-frequency sub-section, and reducing the weight may indicate an increase in the importance of the rank of the corresponding average amplitude magnitude. have. In addition, at this time, the frequency-sweep order may be determined in the order of the smallest sum of the weights of the rank of the average amplitude magnitude and the determined high-spotness rank.

In addition, the device may perform frequency sweeps at a second sweep interval from a sub-region having a higher rank according to the determined frequency sweep rank. At this time, the second sweep interval may be variable even within one sub-region.

For example, the device may determine the best-ranked sub-interval according to the determined frequency-sweep order. In addition, the apparatus calculates slopes representing the amplitude change of the ultrasound compared to the frequency change of the corresponding ultrasound between two adjacent sweep frequencies at the first sweep interval among the plurality of sweep frequencies according to the first sweep interval in the sub-section of the highest priority. can do. In addition, the apparatus may determine, based on the calculated slopes, a peak sweep frequency that is greater than a slope between an adjacent preceding sweep frequency and a slope adjacent to the adjacent trailing sweep frequency by a first sweep interval among a plurality of sweep frequencies. In this case, the apparatus may perform frequency sweep in a second sweep interval smaller than the first sweep interval, in a region from a preceding sweep frequency adjacent to the determined peak sweep frequency to a trailing sweep frequency adjacent to the peak sweep frequency. At this time, the second sweep interval may be the minimum sweep interval.

For example, in the above-described step 320, for each of the plurality of sweep frequencies determined at the first sweep interval, a region including the resonance frequency may be determined using the obtained frequency and amplitude information of ultrasonic waves. Specifically, according to the determined order, any three consecutive sweep frequencies determined by the first sweep interval in the sub-rank of the highest rank are referred to as f1, f2, and f3 (where f1 <f2 <f3), and three When the amplitudes of ultrasonic waves at each of the sweep frequencies are called I_u1, I_u2, and I_u3, and the frequencies of ultrasonic waves at each of the three sweep frequencies are f_u1, f_u2, and f_u3, the device satisfies Equation 1 below. Can be determined to meet the conditions including the resonance frequency.

As it is determined that the conditions for resonant frequency inclusion are met, frequency-swept may be performed in a frequency range from f1 to f3 with a minimum sweep interval.

At this time, it is possible to determine whether the sub-regions of the next rank, such as sub-regions of the next highest rank, also meet the above-described resonance frequency inclusion conditions, and when a plurality of regions meet the resonance-frequency inclusion conditions In a plurality of regions, a sweep frequency at which the amplitude value of ultrasonic waves is maximum may be determined as a resonance frequency.

4 is a block diagram of an apparatus for removing a scale according to an embodiment.

Referring to FIG. 4, the device 400 may include a processor 410, an oscillation unit 420, an ultrasonic generation unit 430, and an ultrasonic sensing unit 440.

In the apparatus 400 illustrated in FIG. 4, only components related to the present exemplary embodiments are illustrated. Accordingly, it will be apparent to those skilled in the art that the device 400 may further include other general-purpose components in addition to those shown in FIG. 4. The apparatus 400 illustrated in FIG. 4 may perform the embodiment described with reference to FIG. 3 as well as other drawings.

The processor 410 may be implemented as a central processing unit (CPU), graphics processing unit (GPU), or application processor (AP), but is not limited thereto.

The oscillator 420 may output an electrical signal determined by the processor. For example, as frequency-sweep is performed by the processor, the oscillator 420 may generate a pulse wave having a corresponding sweep frequency at each sweep point, but is not limited thereto. At this time, the pulse wave may have various duty cycles, and may have a 50% duty cycle, but is not limited thereto.

The ultrasonic generator 430 may physically vibrate as an electrical signal is applied. At this time, the ultrasonic generator 430 may generate ultrasonic waves by changing the ambient pressure. The ultrasonic generator 430 may receive an electrical signal output from the oscillator 420 as an input signal. At this time, the output signal of the oscillation unit 420 may be amplified through an amplifier and then input to the ultrasonic generator 430. As described above, the ultrasonic generator 430 may be physically deformed by magnetic properties being deformed by an electrical signal. For example, the ultrasonic generator 430 may include a magnetostrictive element. At this time, the magnetostrictive element may convert an electrical signal into physical vibration energy.

Also, the ultrasonic generator 430 may include a guide. The frequency may transmit physical vibration energy through the guide 430 to a scale removal object contacting the guide. For example, when the object to be descaled is a heat transfer tube, it contacts the heat transfer tube through a guide, and the physical vibration energy generated by the ultrasonic generator 430 is transferred to the heat transfer tube, thereby allowing the heat transfer tube to be external and internal. Propagating ultrasound waves may be generated.

At this time, when the physical vibration frequency of the ultrasonic generator 430 is the same as the natural frequency of the heat transfer tube, resonance may occur and vibration having a larger amplitude may occur. In addition, when resonating, cavitation can be effectively generated because the sound pressure of ultrasonic waves affects the fluid flowing inside the tube. At this time, the scale inside the tube may be removed through pressure and heat generated as the generated cavitation collapses.

The ultrasonic sensing unit 440 may detect the generated ultrasonic waves. For example, the ultrasonic sensing unit 440 may be physically deformed by sound pressure of ultrasonic waves, and convert them into electrical signals. As described above with reference to FIG. 1, the ultrasonic sensing unit 440 may be a piezoelectric element, and may have, for example, a thin film shape.

The electrical signal converted by the ultrasonic sensor 440 may include amplitude information and frequency information of ultrasonic waves. The ultrasonic sensing unit 440 may transmit the converted electrical signal to the processor 410.

The processor 410 may adjust the frequency of the output signal of the oscillation unit 420 using the electrical signal received from the ultrasonic sensing unit 440 as a feedback signal. For example, the processor 410 may change the frequency of the oscillator 420 while performing frequency-sweep. In addition, the processor 410 may acquire amplitude information of ultrasonic waves based on an electrical signal received from the ultrasonic sensor 440. In addition, the processor 420 may acquire frequency information of ultrasonic waves from the received electrical signal by performing frequency analysis, for example, Fast Fourier Transform (FFT). For example, the processor 420 may acquire a frequency having a maximum amplitude component and a maximum amplitude component at that time.

The processor 410 may divide a frequency domain of interest, which is a frequency domain in which frequency-swept is performed on the output signal of the oscillator 420, into a plurality of sub-regions.

As described above, the frequency domain of interest represents a frequency domain defined by a predetermined lower frequency and upper frequency in performing frequency-sweeping on the output signal of the oscillator 420. The frequency region of interest may be, for example, a frequency section in which the lower limit is 15 kHz and the upper limit is 28 kHz, but is not limited thereto, and may be determined in various ranges according to the structure and type of the scale removal target.

The processor 410 may divide the determined frequency region of interest into a plurality of sub-regions. For example, the processor 410 may divide the frequency region of interest into a plurality of sub-regions having the same section length. The number of sub-regions can be variously determined. For example, as the number of sub-regions increases, the reliability of the sweep order between sub-regions may increase as described below, but the time spent on this may increase.

For example, the section length of each of the sub-regions may be determined by a predetermined multiple of the predicted value of the bandwidth of the resonant frequency according to the amplitude characteristic of the ultrasound according to the frequency. At this time, as the number of frequency domains increases, that is, as the interval length of each of the sub-regions decreases, the weight for the rank of the average amplitude magnitude increases as described below, and the The weight can be reduced.

The processor 410 performs frequency-sweeping at a first sweep interval greater than a minimum sweep interval in each of the divided sub-regions, and at each sweep frequency, the amplitude amplitude of the ultrasound waves generated by the ultrasound generator 430 Can be obtained.

The processor 410 may sweep the frequency of the output signal of the oscillation unit 420 at a first sweep interval greater than a minimum sweep interval in a plurality of sub-regions.

Also, as the processor 410 sweeps the frequency, the amplitude of the ultrasound corresponding to the frequency of the output signal may be obtained. Accordingly, the processor 410 may acquire each of amplitude amplitudes of ultrasonic waves generated from the output signal, for each of the plurality of sweep frequencies determined by sweeping the frequency at the first sweep interval in the sub-region. As described above, the processor 410 analyzes the electrical signal received from the ultrasonic sensor 440 to obtain each of the amplitudes of the ultrasonic waves.

The first sweep interval may correspond to a predetermined multiple of the minimum sweep interval. In determining the characteristics of each of the plurality of sub-regions within the frequency domain of interest, the first sweep interval determines precision. The first sweep interval may be determined based on a previously performed sample experiment result or simulation result.

The processor 410 may determine the rank of the average amplitude size between sub-regions based on the amplitude sizes of the acquired ultrasound waves.

The processor 410 may acquire the magnitude of the average amplitude of ultrasound for each sub-region. At this time, the processor 410 may calculate the average amplitude size of the ultrasound waves using only amplitude sizes of the ultrasound waves having a size equal to or greater than a predetermined threshold amplitude. At this time, the amplitude of the ultrasound may indicate the amplitude of the ultrasound corresponding to the maximum frequency component constituting the ultrasound obtained through frequency domain analysis. Alternatively, the amplitude size of the ultrasound may indicate the frequency of the oscillation unit 420, that is, the amplitude of the ultrasound corresponding to the frequency component of each sweep frequency. However, in addition to this, the amplitude of the ultrasonic waves for calculating the average amplitude size of the ultrasonic waves may be processed in various ways.

The processor 410 may compare the average amplitude magnitude calculated for each of the plurality of sub-regions to determine the rank of the average amplitude magnitude. At this time, in order to determine the rank of the average amplitude size, the processor 410 may quantize the average amplitude size according to a predetermined quantization interval. This is to reduce the effect of small differences caused by noise or errors on the results.

The processor 410 ranks the high-end retention ranking determined according to the size of the sum of the average amplitude size of each of the plurality of sub-regions and the average amplitude size of at least one sub-region adjacent to each of the plurality of sub-regions, It can be determined for each of the sub-regions.

At this time, the fact that the two sub-regions are adjacent may indicate that the upper limit of one sub-region of the two sub-regions is the same as the lower limit of the other sub-regions. Alternatively, k adjacent sub-regions adjacent to one sub-region indicate k sub-interesting frequency regions determined in a small order of distance from one sub-region among sub-regions other than one sub-region.

The high-maintenance ranking may be determined based on the average amplitude size of each of the plurality of sub-regions and the average amplitude size of at least one adjacent sub-region. The high-maintenance ranking of one sub-region is the average amplitude size of the sub-frequency region adjacent to the lower limit of the day sub-swept-frequency, the average amplitude magnitude of the day sub-region, and the average amplitude of the sub-region adjacent to the upper limit of the day sub-region. It can be determined based on the average of the sizes. At this time, the rank of the average amplitude size may be used instead of the average amplitude size. If the lower limit or upper limit of the sub-area is equal to the lower or upper limit of the entire frequency domain of interest, respectively, if it is the first sub-region containing the smallest sweep-frequency or the last sub-region containing the largest sweep-frequency, the corresponding interval, respectively The high-maintenance ranking may be determined using an average amplitude size or a rank of the average amplitude size of at least one sub-region adjacent to the upper or lower limit of.

The processor 410 may determine a frequency-swept order between a plurality of sub-intervals based on the determined rank of the average amplitude magnitude and the determined rank of the high peak retention.

The processor 410 may determine weights for each of the determined average amplitude magnitude ranking and the determined high peak maintenance ranking. For example, the weight of the rank of the average amplitude size may decrease as the number of the plurality of sub-regions is small. In addition, the weight of the high-point maintenance rank may decrease as the number of the plurality of sub-regions is small. At this time, the rank may be inversely proportional to the magnitude of the amplitude of the corresponding sweep-frequency sub-section and / or adjacent sweep-frequency sub-section, and reducing the weight may indicate an increase in the importance of the rank of the corresponding average amplitude magnitude. have. In addition, at this time, the frequency-sweep order may be determined in the order of the smallest sum of the weights of the rank of the average amplitude magnitude and the determined high-spotness rank.

5 and 6 are diagrams for describing an algorithm for determining a sweep order of sub-regions.

In step 505, the device may set the amplitude threshold value I_th. At this time, the amplitude threshold value is a reference value for excluding if the amplitude of the ultrasonic wave cannot be accurately measured due to noise or the like.

In addition, the device may set the first sweep interval f_sw, sub. In determining the sweep order of a plurality of sub-regions as described above, by performing frequency-swept with a sweep interval greater than the minimum sweep interval, time spent than sweeping the entire frequency domain of interest with the minimum sweep interval can be reduced. .

Also, the device may set an initial value of the identification index n of each of the N sub-regions. For example, the device may set n to 1. At this time, n represents an integer from 1 to N, but in addition, an index may be assigned to each of the plurality of sub-regions in various ways to distinguish the plurality of sub-regions.

In operation 510, a lower limit frequency f_l, n and an upper limit frequency f_u, n of the nth sub-region, which is the current sub-region, may be obtained. At this time, the frequency domain from the limit frequency f_l, n to the upper limit frequency f_u, n corresponds to the nth sub-region.

Hereinafter, step 515 to step 540 represents an algorithm for performing frequency-swept on a sub-region.

In step 515, the apparatus may set the oscillation frequency fo, which is the frequency of the signal output from the oscillation unit, to the lower limit frequency f_l, n of the nth sub-region. This is an example of setting an initial sweep frequency in a bottom-up frequency-sweep method, and various other methods may be used.

In step 520, the device may acquire amplitude fu and amplitude Iu of the ultrasonic wave corresponding to the oscillation frequency fo.

At this time, the frequency and amplitude of the ultrasonic wave corresponding to the oscillation frequency indicate the frequency and amplitude of the ultrasonic wave generated by the ultrasonic wave generator by setting the frequency of the output signal of the oscillator to the corresponding oscillation frequency (or sweep frequency).

For example, ultrasonic waves may have a plurality of continuous or discrete frequency components in addition to the frequency components of the oscillation frequency fo due to fluctuations in frequency characteristics during energy conversion. Therefore, the frequency fu of the ultrasonic wave is a center frequency representing the maximum frequency component, and the amplitude Iu of the ultrasonic wave can represent the amplitude at the center frequency. At this time, the frequency fu of ultrasonic waves may be the same or the same frequency as the oscillation frequency fo, but is not limited thereto.

In step 525, the apparatus may determine whether the amplitude Iu of the obtained ultrasound wave is greater than the amplitude threshold value I_th. As described above, when the amplitude Iu of the ultrasound is less than or equal to the threshold I_th due to noise or the like, the corresponding amplitude is excluded when calculating the average amplitude within the sub-section.

If it is determined in step 525 that the amplitude Iu of the ultrasound is greater than the amplitude threshold value I_th, the amplitude Iu of the acquired ultrasound may be added to List_Iu, which is a list of amplitudes acquired in the nth sub-region. The amplitude list List_Iu can be reset before sweeping the frequency-swing for the next sub-region.

In step 535, the device may sweep the oscillation frequency into the first sweep interval f_sw, sub. That is, the current oscillation frequency can be changed by f_sw, sub (fo = fo + f_sw, sub).

In operation 540, the apparatus may determine whether the changed oscillation frequency fo is smaller than the upper limit frequency f_un of the nth sub-region.

In step 540, as the device determines that fo is less than f_un, it may return to step 520 and perform frequency-swept repeatedly.

In step 540, the device may perform step 545 as it determines that fo is not less than f_un.

In step 545, the device may obtain an average amplitude of the nth sub-region. For example, the apparatus may acquire the average amplitude I_n, avg of ultrasonic waves in the n-th sub-region by using the amplitude list List_Iu obtained by performing frequency-swept in the n-th sub-region.

In addition, in step 550, the apparatus may determine whether the number of sub-regions N equal to the sub-region index n is equal to determine whether the current n-th sub-region is the last sub-region.

In step 550, as the device determines that n is not equal to N, in step 555 the index n of the sub-region is updated to n + 1 in order to perform a frequency-sweep on the next sub-region, and the process returns to step 510. Can perform the steps of

In step 550, the device may perform step 560 as it determines that n is equal to N.

In step 560, the apparatus may determine the sweep order of each of the N sub-regions. This will be described with reference to FIG. 6.

In FIG. 6, in step 605, the device sets the index n to identify the sub-region to 0 to determine the sweep order of the N sub-regions, and in step 610 the device updates n to n + 1 to first sub The subsequent steps are performed on the region.

In step 615, the device may determine whether n is 1 to determine whether the nth sub-region is the first sub-region. At this time, as the device determines that n is 1, in step 625, the average amplitude I_n, cont of the adjacent section for calculating the high-point retention is the average value of I_n + 1, avg and I_n, avg, that is, (I_2, It can be determined as avg + I_1, avg) / 2. This is to use only the average amplitude of the second sub-region because there is no sub-region of a lower band than the first sub-region. However, in addition to this, the average amplitude of adjacent sections of the first sub-region can be calculated in various ways.

As it is determined in step 625 that n is not 1, in step 620 the device may determine whether n is N to determine whether the current nth sub-region is the last sub-region. In step 620, as n is determined to be N, in step 635, the device sets the average amplitudes I_n, cont of adjacent sections to the average values of I_n-1, avg and I_n, avg, that is, (I_N-1, avg + I_N, avg) / 2. Similar to the first sub-region, since there is no sub-region of a higher band than the N-th sub-region, the average amplitude of the adjacent region is calculated using only the average amplitude of the N-1 sub-region and the N + 1 sub-region. In addition to this, the average amplitude of the adjacent regions can be calculated in various ways.

As determining in step 620 that n is not N, in step 635, the device sets the neighbor region average amplitude I_n, cont of the n-th sub-region to the average of the preceding adjacent sub-region, the current sub-region, the trailing adjacent sub-region, i.e., I_n, It can be determined as cont = (I_n-1, avg + I_n, avg + I_n + 1, avg) / 3.

After performing steps 620 and 630, the process returns to step 610 to calculate the average amplitude of the adjacent region for the next sub-region, and updates the sub-region index n to n + 1, and then performs the subsequent steps.

As n is determined to be N in step 620, since the current nth sub-region is the last sub-region, the apparatus may perform step 635 after performing step 635.

In operation 640, the apparatus may determine the sweep order Rank_n of each of the N sub-regions. The apparatus may use the result of summing the weights w1 and w2 to the rank rank1_n of the average amplitude size according to the magnitude order of the average amplitude of each of the sub-regions, and the high-ranking rank rank2_n according to the average amplitude size of the adjacent sections, respectively. As described above, the ranking importance of the average amplitude size may increase as the number of sub-regions increases, and the importance of the high-maintenance ranking may decrease. At this time, as the sweep order Rank_n is smaller, it indicates a sub-region of priority, so as the importance of the amplitude magnitude increases, w1 becomes smaller, and w2 can also be inversely proportional to the importance of the high-point maintenance ranking. .

7 is a view for explaining a method of adjusting the sweep interval within each sub-region.

In the graph shown in FIG. 7, the horizontal axis represents frequency and the vertical axis represents the amplitude of ultrasonic waves corresponding to the frequency. At this time, the frequency domain from fs to fe is the frequency domain of interest, and in FIG. 5, five sub-regions of sub-regions of the frequency domain of interest are illustrated, but the number of sub-regions is not limited thereto.

According to the frequency-swept order determined based on the ranking of the minimum amplitude magnitude obtained by performing the frequency-sweep with the first sweep interval greater than the minimum sweep interval in FIG. 7 and the peak retention rank, the fourth sub-region It has the highest priority.

At this time, f1 represents the lower limit frequency of the fourth sub-region, and f2 and f3 are frequencies having a first sweep interval sequentially from f1. f1, f2, and f3 all correspond to the sweep frequencies determined in the step of performing frequency-swept at a first sweep interval to determine the frequency-sweep order of sub-projections. This is the case where the horizontal axis represents the frequency of the output signal of the oscillation unit.

In performing the frequency-sweep in the fourth priority sub-area with higher priority than the first sweep interval, the sweep interval may be adjusted.

At this time, in order to increase the efficiency of the frequency-sweep, it is possible to determine the frequency domain to perform the frequency-sweep in a minimum unit. This may be performed using the amplitude and / or frequency information of ultrasonic waves obtained through the frequency-sweep of the first sweep interval described above.

For example, the frequency of the ultrasonic wave obtained when the oscillation frequency is f1 is represented by f_u1, the amplitude of the ultrasonic wave is I_u1, the frequency of the ultrasonic wave obtained when the oscillation frequency is f2, f_u2, the amplitude of the ultrasonic wave is represented by I_u2, and the oscillation frequency When f3 is f_u3, the frequency of the acquired ultrasonic wave is represented by f_u3, and the amplitude of the ultrasonic wave is I_u3.

At this time, when the following equation (2) is satisfied, it can be determined that there is a resonance frequency between f1 and f3.

In addition, the device determines that there is a resonance frequency between f1 and f3, and performs frequency sweep with a minimum sweep interval from f1 to f3 to determine the frequency of the output signal of the oscillation unit at the sweep frequency when the amplitude of ultrasonic waves is the maximum. It can be set, and the frequency of the ultrasonic wave generated at this time corresponds to the resonance frequency.

As described above, since the amplitudes I_u1 to I_u3 of the ultrasound waves and the frequencies f_u1 to f_u3 of the ultrasound waves can all use the values obtained in the frequency-sweep step of the first sweep interval described above, some of the sub-regions in which the resonance frequency exists Since a separate frequency-sweep is not required to determine the area, that is, the area from f2 to f3 in FIG. 7, it is possible to reduce the time required for frequency-sweep to match the resonance frequency. It is apparent to those skilled in the art that f1, f2, and f3 in FIG. 7 are three frequencies of an arbitrary first sweep interval set for explanation, and f1 may not be the lower limit frequency of the fourth sub-region. In addition, the sweep frequency f1, f2, f3 may be used instead of the frequency of ultrasonic waves.

8 is a flowchart of a frequency sweep method performed by a scale removing device according to another embodiment.

The method of FIG. 8 may be performed by the apparatus of FIG. 4 (400 of FIG. 4).

In step 810, the device generates ultrasonic waves at each of the sweep frequencies, which are frequencies of the selected output signal, as the apparatus performs frequency-swept with a third sweep interval greater than a minimum sweep interval in a frequency domain of interest, which is a frequency domain in which frequency-sweep is performed. It is possible to obtain the amplitude of the ultrasonic wave generated by the unit and the frequency of the ultrasonic wave.

In step 820, the device acquires a first slope that is a ratio of amplitude change to frequency change of ultrasonic waves between a first sweep frequency and a second sweep frequency that is greater than the first sweep frequency among the three sweep frequencies consecutive at the third sweep interval. You can. That is, when the oscillation frequency is the first sweep frequency, the frequency of the ultrasonic wave generated by the corresponding output signal and the amplitude and the oscillation frequency of the ultrasonic wave is the second sweep frequency, the frequency of the ultrasonic wave and the ultrasonic wave generated by the corresponding output signal Using the amplitude, the first slope of the ratio of the amplitude difference of the ultrasound to the frequency difference of the ultrasound can be obtained.

In operation 830, the device may acquire a second slope that is a ratio of amplitude change to frequency change of ultrasonic waves between the second sweep frequency and the third sweep frequency.

In operation 840, the device may determine whether the obtained second slope is smaller than the obtained first slope.

In operation 850, the device may perform frequency-swept at a fourth sweep interval from a first sweep frequency to a third sweep frequency period as it determines that the first gradient is less than the second gradient. At this time, the fourth sweep interval may be the minimum sweep interval.

As the apparatus performs frequency-sweeping at a fourth sweep interval, the sweep frequency at which the amplitude of the generated ultrasonic waves is maximum can be determined as the frequency of the oscillation unit. That is, it indicates that the frequency of the ultrasonic wave generated at this time is the resonance frequency.

The above description of the present invention is for illustration only, and a person having ordinary knowledge in the technical field to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the present invention is indicated by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted to be included in the scope of the present invention. .

Claims (5)

An oscillation unit for outputting an electrical signal and an ultrasonic generator for generating ultrasonic waves by changing the output signal of the oscillation unit into physical vibrations, and controlling a device for removing scale by using cavitation generated by the ultrasonic waves In the way,
Dividing a frequency domain of interest, which is a frequency domain in which frequency-sweep is performed, into a plurality of sub-regions;
In each of the divided sub-regions, as the frequency-swept is performed at a first sweep interval greater than a minimum sweep interval, which is a minimum frequency interval between adjacent frequencies distinguished by the device, ultrasound generated by the ultrasound generator Obtaining amplitude magnitudes and frequencies of;
Determining a rank of an average amplitude magnitude between the sub-regions based on the amplitude magnitudes of the acquired ultrasound waves;
Each of the plurality of sub-regions may have a high-point maintenance ranking determined according to a sum result of an average amplitude size of each of the plurality of sub-regions and an average amplitude size of at least one sub-region adjacent to each of the plurality of sub-regions, respectively. Determining against; And
Determining a frequency-swept order between the plurality of sub-regions based on the weighted sum of the determined average amplitude magnitude and the determined high point maintenance ranking;
According to the determined order, three consecutive sweep frequencies determined by the first sweep interval in the highest priority sub-area are referred to as f1, f2, and f3 (where f1 <f2 <f3), and the three When the amplitudes of ultrasonic waves at each of the sweep frequencies are referred to as I_u1, I_u2, and I_u3, and the frequencies of ultrasonic waves at each of the three sweep frequencies are f_u1, f_u2, and f_u3, a condition including a resonance frequency satisfying Equation 1 below Determining whether or not to meet; And
-Equation 1-

And determining that the resonant frequency inclusion condition is met, performing frequency-swept with a minimum sweep interval for the frequency domains from f1 to f3. According to claim 1,
Acquiring an amplitude of ultrasonic waves by performing frequency-swept at a minimum sweep interval from f1 to f3; And
And determining a sweep frequency at which the amplitude of the obtained ultrasonic wave is the maximum as a resonance frequency. In the descaling device,
An oscillation unit for outputting an electrical signal;
An ultrasonic generator that generates ultrasonic waves by changing the output signal of the oscillator into physical vibration;
An ultrasonic sensing unit that senses ultrasonic waves and outputs electrical signals including amplitude and frequency information of the detected ultrasonic waves; And
It includes a processor for performing a frequency-sweep on the output signal of the oscillation unit using the output signal of the ultrasonic sensor,
The processor,
The frequency domain of interest, which is a frequency domain in which frequency sweep is performed, is divided into a plurality of sub-regions,
In each of the divided sub-regions, amplitude amplitudes of ultrasonic waves generated by the ultrasonic generator are obtained by performing frequency-swept with a first sweep interval greater than a minimum sweep interval,
Based on the amplitude amplitudes of the acquired ultrasound waves, a ranking of the average amplitude size between the sub-regions is determined,
Each of the plurality of sub-regions may have a high-point maintenance ranking determined according to a sum result of an average amplitude size of each of the plurality of sub-regions and an average amplitude size of at least one sub-region adjacent to each of the plurality of sub-regions, respectively. Decide on,
The frequency-swept order between the plurality of sub-regions is determined based on the determined rank of the average amplitude magnitude and the determined rank of high point retention,
According to the determined order, three consecutive sweep frequencies determined by the first sweep interval in the highest priority sub-area are referred to as f1, f2, and f3 (where f1 <f2 <f3), and the three When the amplitudes of the ultrasonic waves at each of the sweep frequencies are called I_u1, I_u2, and I_u3, and the frequencies of the ultrasonic waves at each of the three sweep frequencies are f_u1, f_u2, and f_u3, a condition including a resonance frequency satisfying Equation 2 below To determine if
-Equation 2-

Upon determining that the resonant frequency inclusion condition is met, the apparatus performs frequency-swept with a minimum sweep interval for the frequency domains from f1 to f3. The method of claim 3,
The ultrasonic generator includes a magnetostrictive element that physically vibrates by changing magnetic characteristics when the output signal of the oscillation unit is applied. The method of claim 4,
The ultrasonic sensing unit outputs an electrical signal including information on the amplitude and frequency of the ultrasonic wave as it is physically deformed by the sound pressure of the ultrasonic wave.

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