Technical field [0001]The present invention relates to an ultrasonic cleaning apparatus and an ultrasonic cleaning method. BACKGROUND [0002]Generally, in the manufacturing process of various metal bodies such as steel sheets and steel pipes, in order to remove scale produced on the surface of the metal body or the like, washing the metal body immersed sequentially in the cleaning tank chemical solution or rinsing, and the like are held performing, cleaning method has been widely adopted. Such cleaning method the cleaning apparatus for carrying out, for example, cleaning apparatus or using a high pressure air stream injection nozzle, there is an ultrasonic cleaning device or the like that utilizes ultrasonic waves. [0003]As ultrasonic cleaning method using such an ultrasonic, for example, Patent Document 1 below, the ultrasonic cleaning tank, the transducer face λ / 4 · (2n-1) [λ: Wavelength, n: any integer a position, a method of installing an ultrasonic reflector parallel to the transducer surface has been proposed. [0004]Further, Patent Document 2 below, by applying with the addition of microbubbles in the cleaning liquid, the ultrasonic waves having two different frequencies contained within the following frequency 28.0kHz above 1.0 MHz, super further techniques to improve the cleaning effect using sound waves have been proposed. CITATION Patent Document [0005]Patent Document 1: JP-A-6-343933 JP Patent Document 2: WO 2011/067955 Summary of the Invention Problems that the Invention is to Solve [0006]However, the method is to install a reflecting plate parallel to the transducer surface, since it is a method for reflecting the ultrasonic waves by such reflection plate, or a surface of the reflector is curved proposed in Patent Document 1 If the projection is or are present effectively it is difficult to reflect the ultrasonic cleaning efficiency decreases. The reflection plate is proposed in Patent Document 1, a flat plate, in this case occurs standing wave by ultrasonic, small area intensity of the ultrasound occurs. As a result, cleaning unevenness will occur can not be uniform cleaning. Furthermore, in such a way, the portion to be shaded from the transducer surface can not be cleaned by ultrasound, it is difficult to perform cleaning with efficient ultrasound throughout treatment tank. [0007] 　In the technique proposed in Patent Document 2, 2 The type of uses ultrasonic waves having a frequency, difficult matching of the two ultrasonic waves of different frequencies, is washable object and cleaning area thus limited to. [0008] 　The present invention has been made in view of the above problems, it is an object of the present invention, it is possible to more efficiently propagates ultrasonic throughout treatment tank, regardless of the object to be cleaned, capable of more efficiently cleaning the cleaning object is to provide an ultrasonic cleaning apparatus and an ultrasonic cleaning method. Means for Solving the Problems [0009] 　The present inventor has conducted extensive studies in order to solve the above problems, a curved member having a predetermined shape, by installing in place inside of the processing tank which is held in the cleaning liquid, the entire treatment tank over ultrasound can more efficiently propagate, regardless of the object to be cleaned, with the knowledge that it is possible to more efficiently clean the object to be cleaned, the present invention detailed below completed. 　Summary of the completed invention based on this finding is as follows. [0010] [1] containing a cleaning liquid for cleaning the object to be cleaned, said the treatment tank to be washed is immersed, and ultrasonic wave application mechanism for applying ultrasonic waves to the cleaning liquid held in the interior of the processing bath the relative vibration surface of the ultrasonic wave application mechanism, located within the range defined by a predetermined inclination angle outward from the normal direction at the end of the vibrating surface, the wall and / or bottom surface of the processing bath comprising a curved member held, wherein the curved member is present the convex curve portion at least having a spherical or aspherical surface shape, the convex curved portion, the vibration surface than portions other than the convex curved portion has a convex curved surface in a state of projecting to the side, the irradiated from the ultrasonic application mechanism, and the convex at least a portion of the first acoustic wave is a sound wave generating no reflection the convex curved surface to reach the curved portion, the convex curved surface is the vibrating It is held in a state facing the ultrasonic cleaning device. [2] the maximum height H of the convex curved portion of the convex curved surface, the wavelength of the ultrasonic wave is taken as lambda, satisfies the relationship of lambda / 2 　The processing tank 10, and the washing liquid 3 to be used for washing the object to be cleaned, the object to be cleaned is accommodated. The type of cleaning liquid 3 held in the processing tank 10, is not particularly limited, depending on the processing performed on the object to be cleaned, it is possible to use a known cleaning liquid. Further, the washing liquid 3, the purpose of further improvement of the cleanability, such as a known particle may be further added. [0021] 　Here, material used to form the processing tank 10 according to the present embodiment is not limited in particular, iron, steel, it may be a variety of metal materials such as stainless steel or the like, fiber-reinforced plastic may be a variety of plastic resins such as (FRP), polypropylene (PP) or the like, may be various types of bricks, such as acid brick. That is, as the processing tank 10 constituting the ultrasonic cleaning device 1 according to the present embodiment, it is also possible to prepare new processing vessel formed of a material as described above, existing in the various production line it is also possible to use a processing tank. [0022] 　Also, there are no particular limitation on the size of the processing tank 10, even when a large treatment tank having various shapes, such as about liquid level depth 1 ~ 2m approximately × total length 3 ~ 25 m, the present embodiment it is available as a processing bath 10 of the ultrasonic cleaning device 1 according to the. [0023] 　Further, walls and / or bottom curved member 30 which will be described later in the cleaning tank 10 is arranged, preferably it has no recess. Thereby, ultrasonic waves are focused by concave, part of the ultrasonic wave can be prevented from being unavailable. [0024] 　ultrasonic application mechanism 20, to the washing liquid 3 and the object to be cleaned which are accommodated in the processing tank 10, applies an ultrasonic wave of a predetermined frequency. Ultrasonic application mechanism 20 is not limited in particular, such as ultrasonic transducers connected to the ultrasonic oscillator not shown, it is possible to use a known. Further, in FIG. 1A ~ FIG 1D, are illustrated for the case of providing the ultrasonic application mechanism 20 on the wall surface of the processing tank 10, which is particular limitation on the installation position of the processing tank 10 of the ultrasound applying mechanism 20 rather, with respect to the wall surface and the bottom surface of the processing tank 10, one or a plurality of ultrasonic transducers may be appropriately installed. Incidentally, if a condition such as uniformly ultrasound throughout the processing bath 10 is propagated, the balance of the oscillating load of the individual ultrasonic transducers becomes uniform, the number of ultrasonic transducers had a plurality even, interference does not occur between the ultrasonic waves generated. [0025] 　Frequency of the ultrasonic wave output from the ultrasonic application mechanism 20 is preferably, for example, a 20 kHz ~ 200kHz. By frequency of the ultrasonic wave is within the above range, it is possible to suitably remove scale present in the metal body, for example, steel surfaces. When the frequency of the ultrasound is less than 20kHz is ultrasonic propagation is hindered by large bubble size generated from the surface of the object to be cleaned, there is a case where the cleaning improving effect by the ultrasonic wave is lowered. Further, when the frequency of the ultrasonic wave is higher than 200kHz is too strong straightness of the ultrasound when cleaning the object to be cleaned, the uniformity of cleaning may be reduced. Furthermore, depending on device configuration of the ultrasonic cleaning device 1, there is a case where removal of the scale is difficult. Frequency of the ultrasonic wave output from the ultrasonic application mechanism 20 is preferably 20 kHz ~ 150 kHz, more preferably 25 kHz ~ 100kHz. [0026] 　Incidentally, the ultrasonic frequency to be applied, it is preferable to select an appropriate value within the above range according to the object to be cleaned, depending on the type of object to be cleaned, by applying ultrasonic waves of two or more frequency it may be. [0027] 　The ultrasonic application mechanism 20 is capable of applying ultrasonic waves while sweeping the frequency range of ± 0.1 kHz ~ ± 10 kHz around the frequencies of a selected ultrasound has a frequency sweep function it is preferred that. The reason why it is preferable that the ultrasonic wave application mechanism 20 has a frequency sweep function, anew described below. [0028] 　curved member 30, as described in detail below, a member having a convex curved surface toward the plane of vibration of ultrasonic wave application mechanism 20, the ultrasonic wave having reached the curved member 30 to multidirectional it is a member for reflecting and. Such curved member 30 by providing the at least one of the walls and bottom of the treatment tank 10, and the ultrasonic waves generated from the vibration surface of the ultrasonic applying mechanism 20, be propagated throughout in the processing bath 10 It can become. [0029] 　More specifically, the curved member 30 of the present embodiment, there convexly curved portion having a spherical or aspherical surface shape at least, such a convex curved portion, than the portion other than the convex curve portion, ultrasonic It has a convex curved surface in a state of being protruded to the vibration surface of the applying mechanism 20. [0030] 　2, enumerating an example of curved member 30 of the present embodiment. Incidentally, FIG. 2, the curved member 30 of the present embodiment, illustrates the shape when viewed from the z-axis above the coordinate axes shown in FIGS. 1A ~ FIG 1D. [0031] 　As shown in FIGS. 2, curved member 30 according to this embodiment, the convex surface 31 and having at least, to such convex curved surface 31 is convex curved portion 33 having a spherical or aspherical surface shape It is at least there. In the ultrasonic cleaning device 1 according to the present embodiment, among the curved member 30, a state where the convex curved surface 31 having such a convex curved portion 33 protrudes to the vibration surface of the ultrasonic wave application mechanism 20 and toward the take vibration surface in are held. [0032] 　Further, the curved member 30 according to this embodiment, as shown in FIG. 2 upper, may have a non-convex curve portion 35 is no part convexly curved portion 33, the middle of FIG. 2 and the lower as shown, it may be composed of only the convex surface 31. [0033] 　Furthermore, the curved member 30 according to this embodiment, as shown in FIG. 2 upper and middle, may be a solid columnar member, as shown in FIG. 2 lower part, a hollow tubular member it may be. Further, when the curved member 30 is hollow, the voids of the state of the curved member 30 mounted on the treatment tank 10, to various gases such as air may be present, it is held in the processing bath 10 various liquid cleaning solution 3 and the like may also be present. [0034] 　By curved member 30 has a convex curved surface 31 as described above, ultrasonic waves are reflected into multiple directions, unpolarized uniform ultrasonic propagation is realized, it is possible to suppress interference between ultrasound. As a result, ultrasound diffuse in all directions of the three-dimensional cleaning tank 10, it is possible to uniform cleaning without unevenness. That is, for the object to be cleaned, ultrasonic waves arrived from all angles, the object to be cleaned surface is uniformly cleaned. Here, if the curved member 30 includes a recess, ultrasonic ends up focused by reflection by the recess, can not be reflected effectively ultrasound throughout the processing tank 10. Further, even when including the convex portion, when the convex portion is a flat rather than a curved surface can not be reflected only ultrasonic waves to one direction, effectively ultrasound throughout the processing bath 10 It can not be reflected. [0035] 　The shape of the curved member 30 shown in FIG. 2 are merely examples, the shape of the curved surface member 30 of this embodiment is not limited to the shape shown in FIG. However, a member having a wavy uneven, since the recess is thus focuses the ultrasound, can be difficult to uniformly spread the ultrasound, not included in the curved member 30 according to this embodiment . [0036] 　Here, as shown in each of FIGS. 2, the maximum height H of the convex curved portion 33 in the convex curved surface 31, when the curved member 30 has a convex curve portion 33 and the non-projecting curved portion 35 is a height defined the position of the connection portion of the convex curve portion 33 and the non-projecting curved portion 35 as a reference. Further, when the curved member 30 has only convexly curved portion 33, the radius of the curved surface member 30, the major diameter of 1/2 of the length, corresponding to half the minor axis length ... etc. to the height. Maximum height H of such convex curved portion 33, the wavelength of the ultrasonic waves applied by the ultrasonic wave application mechanism 20 when the lambda, it is preferable that a height that satisfies the relationship of lambda / 2 　Subsequently, again back to FIG. 1B and FIG. 1D, the it is preferred dissolved gas control mechanism 40 ultrasonic cleaning device 1 according to the present embodiment has will be described in detail. 　Dissolved gas control mechanism 40, the dissolved gas content in the washing liquid 3 inside is held in the processing tank 10, and controls within an appropriate range. [0055] 　In the ultrasonic cleaning device 1 according to this embodiment, in order to achieve both more uniform ultrasound propagation and high cleanability, it is preferred to control the dissolved gas content in the washing liquid 3 to an appropriate value. Such suitable dissolved gas volume of the cleaning solution 3 is preferably 50% or less than 1% of the dissolved saturation amount in the washing liquid 3. If the dissolved amount of gas is less than 1% of the dissolved saturated amount, it does not occur cavitation by ultrasonic waves is not preferable because the cleaning improving capability by ultrasound (surface treatment improving capacity) can not be exhibited. On the other hand, when the dissolved gas amount exceeds 50% of the dissolved saturated amount, since the dissolved with gas in the ultrasonic wave propagation is inhibited, a uniform ultrasonic wave propagation to the entire treatment tank 10 is inhibited, which is undesirable. Dissolved gas content in the washing liquid 3 is preferably, 5% to 40% of the dissolved saturated amount in the washing liquid 3. [0056] 　Here, if the temperature of the washing liquid 3 is varied, the dissolved amount of saturation of the washing liquid 3 is varied. Further, due to temperature changes of the washing liquid 3, molecular momentum of the liquid constituting the washing liquid 3 (e.g., water molecules momentum) difference affects the propagation properties. Specifically, if low temperature, the molecular motion of liquid constituting the washing liquid 3 is small, easily propagates ultrasonic waves, dissolved saturation volume of the cleaning solution 3 is also increased. Thus, as can be achieve the desired dissolved gas amount such that within the above range, it is preferable to appropriately control the temperature of the washing liquid 3. Temperature of the washing liquid 3, depending on the specific processing contents carried out using washing liquid 3, for example, is preferably from 20 ° C. ~ 85 ° C. of about. [0057] 　Specifically, dissolved gas content in the washing liquid 3 is, for example, is preferably 0.1ppm or more 11.6ppm less, and more preferably less than 1.0ppm 11.0ppm. Therefore, the dissolved gas control mechanism 40, as dissolved gas content in the washing liquid 3 held in the processing bath 10 has a value of the above range, the dissolved amount of gas temperature and the washing liquid 3 in the cleaning solution 3 Control. [0058] 　The method of controlling a dissolved gas content, vacuum degassing, etc. degassing by chemicals, there are various methods, it is possible to select as appropriate. Further, the dissolved amount of gas in the cleaning liquid 3, such as a diaphragm electrode method and optical dissolved oxygen meter, can be measured by known devices. [0059] 　Here, the gas dissolved in the aqueous solution, primarily, oxygen, nitrogen, carbon dioxide, helium, and argon, although affected by the temperature and composition of the aqueous solution, oxygen and nitrogen accounted for the majority. [0060] 　Subsequently, again back to FIG. 1C and FIG. 1D, the ultrasonic it is preferable that the cleaning device 1 has the fine bubble supply mechanism 50 according to the present embodiment will be described in detail. 　Fine bubble supply mechanism 50, washing liquid fine bubbles having a bubble diameter corresponding to the frequency of the ultrasonic wave applied from the ultrasonic application mechanism 20 (average cell diameter), via a supply tube, which is held in the processing tank 10 and supplies to the 3. The fine bubbles, the average bubble size is fine bubbles is 100μm or less. Among such fine bubbles, fine bubbles having an average bubble diameter of μm size, sometimes referred to as microbubbles, which may average cell diameter of the fine bubble nm size, referred to as nanobubbles. Fine bubbles, to improve the propagation efficiency of the ultrasonic against the object to be cleaned, and improves the cleaning properties as nuclei for ultrasonic cavitation. [0061] 　The average cell diameter of the fine bubbles to be fed into the washing solution is preferably a 0.01 [mu] m ~ 100 [mu] m. Here, the average cell diameter and, in the number distribution about the diameter of fine bubbles, the diameter of the number of samples is maximized. If the average cell diameter is less than 0.01 [mu] m, fine bubble supply mechanism 50 becomes large, there is a case where supply of the fine bubble established a cell diameter becomes difficult. Further, when the average cell diameter exceeds 100μm, the life of the fine bubbles in the cleaning liquid becomes short by ascent rate of fine bubbles increases, practical cleaning may become impossible. Further, if the bubble diameter is too large, the ultrasonic propagation is hindered by the fine bubbles, detergency improving effect possessed by the ultrasound in some cases lowered. [0062] 　The concentration of fine bubbles in the cleaning liquid 3 (density) 10 3 cells / mL ~ 10 10 is preferably cells / mL. The concentration of fine bubbles 10 3 When less than cells / mL, there is a case where the ultrasonic propagation improving effect by the fine bubbles not sufficiently obtained, also become nuclei of ultrasonic cavitation require less cleaning sister, is not preferable. The concentration of fine bubbles 10 10 If it is greater cells / mL are or become large bubble generating device, and or become increasing the number of bubble generator, the practical feeding fine bubbles There is a case where there is no, which is not preferable. [0063] 　Further, the fine bubble supply mechanism 50, during the washing liquid 3, the whole fine bubbles ratio of the number of fine bubbles having a bubble size under frequency resonant diameter or a diameter that resonates with the frequency of the ultrasonic wave is present in the cleaning solution 3 as the number of 70% or more, it is preferable to supply the fine bubbles. The reason for this will be described below. [0064] 　Natural frequency of the various air bubbles containing the fine bubbles, also called Minnaert resonance frequency is given by Equation 101 below. [0065] [Number 1] [0066] 　Here, in the above formula 　　101, f 0 : natural frequency of the bubble (Minnaert resonance 　　frequency) R 0 : the average bubble radius 　　p ∞ : average pressure near the liquid 　　gamma: adiabatic ratio (gamma = 1.4 for air) 　　[rho : liquid density 　is. [0067] 　Now, when the air inside the interest bubbles are present, a near liquid water bubbles, as the pressure to be atmospheric pressure, the product f and the average radius of the natural frequencies and the bubble of the bubble 0 R 0 the value of is about 3 kHz · mm about the above equation 101. Than this, if the ultrasonic wave frequency is 20kHz the applied radius R of bubbles resonate with such ultrasound 0 , since approximately 150 [mu] m, the frequency resonance is bubble diameter resonates with ultrasonic frequency 20kHz diameter 2R 0 is about 300 [mu] m. Similarly, if the ultrasonic wave frequency is 100kHz applied thereto according ultrasonic radius R of the bubble which resonates to 0 , since approximately 30 [mu] m, the frequency resonance is bubble diameter resonates with ultrasonic frequency 100kHz diameter 2R 0 is approximately 60 [mu] m. [0068] 　At this time, the resonant radius R 0 bubbles having a larger radius than is the inhibitor. This is because, when the resonant bubble containing fine bubbles, the bubbles are briefly repeats expansion and contraction and will ultimately crushed, size of the bubbles at the time the first acoustic wave passes through the bubble frequency resonance diameter 2R 0 is greater than, ultrasound is because diffuses bubbles surface. Conversely, the size of the bubbles at the time the first acoustic wave passes through the bubble frequency resonant diameter 2R 0 is smaller than, ultrasound can pass through the bubble without diffusing bubbles surface. [0069] 　From this point of view, in a wash solution 3, the frequency resonant diameter 2R 0 the ratio of the number of fine bubbles having a bubble size of less, it is preferable that 70% or more of fine bubbles whole number present in the washing liquid 3. Frequency resonant diameter 2R 0 by the ratio of the number of fine bubbles having a bubble diameter of less than 70%, it is possible to further improve the propagation efficiency of the ultrasonic wave. Also, by propagating the first acoustic wave to the wall / bottom of the processing tank 10, the diffusion and the reflection of ultrasonic waves to the entire treatment tank 10 is repeated, it is possible to achieve uniform ultrasonic bath sonicator . The frequency resonant diameter 2R 0 can bubbles were below also crushed by repeated expansion and contraction and exceeds a predetermined ultrasonic irradiation time, contribute to the cavitation cleaning. [0070] 　The frequency resonant diameter 2R 0 ratio of the number of fine bubbles having a bubble diameter of less, considering that no small bubbles to expand immediately after the fine bubble is preferably 98% or less. Frequency resonant diameter 2R 0 ratio of the number of fine bubbles having a bubble diameter of less, more preferably 98% or less than 80%. [0071] 　Here, the basic mechanism of fine bubble, shearing of the bubbles, micropores passage of air bubbles, cavitation by reduced pressure (vaporization), pressure dissolution of gas, ultrasound, electrolysis, various mechanisms such as chemical reaction or the like is present and, it is possible to select as appropriate. In fine bubble supply mechanism 50 according to the present embodiment, capable of easily controlling the cell diameter and density of fine bubbles, it is preferable to use the fine bubble generation method. The fine bubble generation method, for example, after generating the fine bubble shearing method, by passing a cleaning liquid to a filter having fine pores of a predetermined size, a method of controlling the bubble diameter of the fine bubbles. [0072] 　Here, the average bubble size and density of fine bubbles (density), such in-liquid particle counter and bubble size distribution measuring apparatus or the like, can be measured by known devices. For example, a laser diffraction scattering method scattered light and Shimadzu SALD-7100H can measure a wide range of bubble size distribution (number nm ~ several hundred [mu] m) calculated from the distribution of, the electricity during the opening passage of the electric resistance method Beckman Coulter Multisizer4 can measure the number and density of μm size from the resistance change, Malvern Ltd. NanoSightLM10 capable of measuring the number and density of nm size from the speed by using the particle Brownian motion observed video in laser beam irradiation in the Brownian motion observation method and the like. [0073] 　Fine bubbles were generated as described above, in the liquid under the conditions of a general cleaning solution 3, it is often the surface potential is negatively charged. On the other hand, the washing object is present on the surface of the object to be cleaned (e.g., scale in steel, smut, oil, etc.), because they often are positively charged, to the vicinity of the fine bubbles cleaned object if reached, by such charging of difference, so that the fine bubbles adsorbed with the object to be cleaned. If ultrasonic cleaning device 1 according to this embodiment has a fine bubble supply mechanism 50, can be further cleaned cleaning objects by generating cavitation by ultrasonic waves fine bubbles is applied, the more efficiently cleaned It can be carried out to become. [0074] 　Note that the wall surface and the bottom surface of the cleaning liquid side of the processing tank 10, it is preferable that the reflecting plate for reflecting the ultrasonic waves are provided. By providing such a reflecting plate, ultrasonic wave having reached the wall surface and the bottom surface of the processing tank 10 is reflected by the reflecting plate, so that the propagates again to towards the washing liquid 3. This makes it possible to efficiently utilize the applied ultrasonic waves in the cleaning liquid 3. In the present embodiment, by a curved member 30 is disposed in the processing tank 10, even when placing the reflective plate, the occurrence of standing waves are prevented. [0075] 　In particular, for example, as schematically shown in FIG. 6, the curved member 30, the wall surface or bottom surface of the processing tank 10 according curved member 30 is held, during, a reflector 60 for reflecting the ultrasonic waves by providing, it is possible to use a more efficient ultrasound. [0076] 　Also, the site where the curved member 30 of the wall surface and the bottom surface of the processing tank 10 is not disposed, the reflection plate may be disposed. By thus reflecting plate is present, the ultrasonic waves are absorbed in the walls and bottom of the processing tank 10 is prevented, and reflected. This makes it possible to efficiently utilize the applied ultrasonic waves in the cleaning liquid 3. Further, in this case, the area of ​​the reflection plate to the site where the curved member 30 of the wall surface and the bottom surface in contact with the cleaning liquid of the processing tank 10 is not disposed may larger, not particularly limited, for example, 80% or more, preferably 90% or more. [0077] 　Above with reference to FIGS. 1A ~ 6, the overall configuration of the ultrasonic cleaning device 1 according to the present embodiment has been described in detail. [0078] (Frequency sweep processing) 　Next, the sweeping process of the frequency in the ultrasonic application mechanism 20 will be briefly described. 　As prior mentioned ultrasonic application mechanism 20 according to this embodiment, be applied to ultrasonic waves while sweeping the frequency range of ± 0.1 kHz ~ ± 10 kHz around the frequencies of a selected ultrasound possible, it is preferable to have a frequency sweep function. Such frequency sweep function, it is possible to realize the two additional advantages described below. [0079] 　Are present in the liquid, the case of applying ultrasonic waves to microbubbles containing fine bubbles, with respect to the microbubbles, and a force called Bjerknes force, microbubbles resonant bubble radius that depends on the frequency R 0 depending on, so that the drawn in position of the ultrasonic belly or section. Here, the frequency sweep function ultrasound applying mechanism 20 has, if the frequency of the ultrasonic wave is changed, the resonant bubble radius R depends on the frequency 0 becomes the spread in accordance with a change in frequency. As a result, it becomes possible to bubble diameter of cavitation spreads, it is possible to use a number of microbubbles (e.g., fine bubbles) as cavitation nuclei. Thus, the frequency sweep function ultrasound applying mechanism 20 has, cleaning efficiency of ultrasonic cleaning device 1 is further improved according to the present embodiment. [0080] 　On the other hand, as a general property of ultrasound, "when the wavelength of the ultrasonic wave becomes a quarter of the wavelength corresponding to the thickness of the irradiated object, ultrasonic waves are transmitted through the irradiation target object" are known phenomenon there. Therefore, by applying ultrasonic waves while sweeping frequency in a suitable range, for example, when objects to be cleaned had a hollow portion of the tubular body such as to increase the ultrasonic wave transmitted to the tubular body it becomes possible, cleaning efficiency of ultrasonic cleaning device 1 is further improved according to the present embodiment. [0081] 　Here, when considering the ultrasound transmission at the irradiation object surface, ultrasound is not only the case of normal incidence radiation object, since propagates while repeating multiple reflection, certain sound field hard to form There is a tendency. Among them, in order to create the conditions for transmitting the wall surface of the irradiation object, even if it exists where the position of the object to be cleaned, "the wavelength of ultrasonic wave, the wavelength corresponding to the thickness of the object to be cleaned 1/4 it is preferable to implement a frequency capable of satisfying the condition that become ". The scope of such a frequency, the present inventors have was examined, by applying ultrasonic waves while sweeping the frequency range of ± 0.1 kHz ~ ± 10 kHz around the frequencies of a selected ultrasound, the ultrasound transmission, such as is found to be feasible. Example [0082] 　Then, while showing Examples and Comparative Examples, the ultrasonic cleaning device and an ultrasonic cleaning method according to the present invention will be specifically described. Note that the embodiments described below are merely examples of an ultrasonic cleaning device and an ultrasonic cleaning method according to the present invention, ultrasonic cleaning device and an ultrasonic cleaning method according to the present invention, limited to the examples shown below not intended to be. [0083] (Experimental Example 1) 　In this experimental example, by using the ultrasonic cleaning device 1 as schematically shown in FIGS. 7A and 7B, the aluminum plate was washed steel plate (rinsing) process. As for the rinsing solution, using purified water at room temperature (25 ° C.). Processing bath 10, the outer wall is made SUS, capacity 7m width 2.0 m × length 7m × depth 0.5 m 3 was used for. Steel to be cleaned was the state held in the roll provided in the processing bath 10. Ultrasonic generator of the ultrasonic application mechanism 20, the output is used as a 1200 W. The frequency of the ultrasonic, 40 kHz (wavelengths in sound speed c = 1500m / s λ: 37.5mm ) and was, as schematically shown in FIGS. 7A and 7B, the processing bath 10 five SUS steel Immersion transducers arranged on the long side side wall surface of, and application of ultrasonic waves. Further, as schematically illustrated in FIGS. 7A and 7B, the processing tank 10 with respect to the wall surface of the ultrasonic vibrator is not provided side, SUS steel Immersion transducers facing the manner five a curved surface member 30 was installed. Regard curved member 30 to be installed in the processing bath 10, the size, shape, material (specific acoustic impedance), the surface area, the distance from the vibration surface, the distance of the curved member 30 with each other by changing respectively, a comparison of the results obtained went. In the present experimental example, as dissolved gas control mechanism 40, with Miura casting type degasser PDO4000P, to control the dissolved gas amount at the time of testing. Using HORIBA Ltd. dissolved oxygen meter LaQua OM-51, the amount of dissolved oxygen was measured as a value proportional to the dissolved gas amount estimated dissolved gas amount relative to the dissolved saturated amount (%). Incidentally, Table 1 below, dissolved gas content 5% In Table 2, 40%, 95%, specific concentrations, respectively 1.1 ppm, 9.1 ppm, which corresponds to 21.5Ppm. Further, the dissolved amount of gas 95% is a value in the case of using a water purification as not subjected to dissolved gas control. [0084] 　In this experimental example, as schematically shown in FIG. 8, using an ultrasonic level monitor (Kaijo manufactured 19001D), 0.5m intervals the length direction of the processing tank 10, the width direction of the processing tank 10 performs measurement of ultrasonic intensity (mV) of a total 26 places the position of 0.5m from the wall surface, the relative intensity of ultrasonic waves (measurement result of Comparative example 1, i.e., if not installed the convex curved portion 33 the measurement ultrasonic intensity by calculating a relative intensity) and standard deviation (sigma) when formed into a 1 in, to compare the propagation of the ultrasonic wave of the entire treatment tank 10. In Comparative Example 5 below, the curved member 30 provided in the same wall as the SUS Immersion transducers are provided, the convex curved portion 33 so as not to face the vibration surface. The experimental conditions and the results obtained in this experiment, Table 1 below, are summarized in Table 2. [0085] 　Incidentally, Table 1 below, in Table 2, among the shape of the curved member those described as "round pipe" is a circular outer shape of the cross section perpendicular to the longitudinal direction, the hollow tubular member means for using, those described as "cylindrical" means that the outer shape of the cross section perpendicular to the longitudinal direction is circular, with a columnar body of a solid. Also, of the shape of the curved member those described as "flat pipe" means that the outer shape of the cross section perpendicular to the longitudinal direction is elliptical, with a hollow tubular body. Furthermore, those described as "corrugated plate (angle)" means for using the corrugated plate wavy portion functioning as a non-convex curve portion 35. Also, of the shape of the curved member those described as "embossing" is meant for using what the hemispheres of φ10mm the plate-like material surface is embossed in a staggered arrangement. Also, of the shape of the curved member those described as "round pipe + shield" is between the SUS Immersion transducers and round pipe ultrasound applying mechanism 20, a shield plate for shielding the first wave It means that the arrangement was. [0086] 　In Table 1, Table 2 below, "the maximum height H" is as described prior, means the maximum height of the convex curved portion 33 which is convex toward the transducer surface, round pipe or cylinder case of a value corresponding to the radius. Further, Table 1 below, in Table 2, "member convexly curved portion area ratio" of the curved member 30, which means the area ratio of the convex curve portion 33 opposed to the transducer surface. Further, Table 1 below, in Table 2, the "number of curved member" means the number of the convex curved portion 33 at one curved member 30, which convex curve portion 33 is continuous, 1 expressed. [0087] [Table 1] [0088] [Table 2] [0089] 　First, looking at Comparative Example, and Comparative Example 2-3 that the curved member 30 is provided in the absence of the convex curve portion 33, the shielding plate provided in front of the convex curved portion 33 so as to block the ultrasound in the first wave compared to Comparative example 4 but present, in Comparative example 5 in which a convex curved portion on the same wall as the vibration surface, and Comparative example 1 which did not hold the curved member 30 to the processing tank according to an embodiment of the present invention , the average of the relative intensity of ultrasonic waves in the entire processing tank 10 did not change substantially. As for the standard deviation which is a distribution index, exceeds the 20 to the ultrasonic intensity 33 mV, it can be seen that the ultrasonic wave propagation is uneven. [0090] 　On the other hand, in Examples 1 to 20 the curved member 30 is provided according to an embodiment of the present invention, the relative intensity of ultrasonic waves showed 1.5 times or more as high. In particular, the separation distance D from the transducer surface is within 2.5 m, and examples having a convexly curved portion 33 at more than 80% of the area ratio of 1% or more in the vibrator scope within 30 ° to the outside in 4-8, it observed twice or more relative ultrasonic intensity, standard deviation was reduced. Further, when changing the shape of the convex curved portion 33 is within the range area of ​​not more than 80% 1%, and the maximum height H of the convex curved portion 33 is lambda / 2