Abstract:
Disclosed herein is a dishwasher using oscillatory flow generated from thermoacoustic effect. The dishwasher is configured such that thermoacoustic waves having high amplitude are generated from solar energy rather than electric energy, wherein the thermoacoustic waves make oscillating waves be directly transmitted to an air column and a water column formed in a closed end of a dishwashing pipeline. In this way, high-quality energy can be directly applied to washing water, whereby energy loss can be minimized, and the washing efficiency can be markedly increased.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a dishwasher using oscillatory flow generated from thermoacoustic effect that is configured such that thermoacoustic waves having high amplitude are generated from solar energy rather than electric energy, wherein the thermoacoustic waves make oscillating waves be directly transmitted to an air column and a water column formed in a closed end of a dishwashing pipeline. In this way, high-quality energy can be directly applied to washing water, whereby energy loss can be minimized, and the washing efficiency can be markedly increased. 
         [0003]    2. Description of the Related Art 
         [0004]    Generally, conventional thermoacoustic wave generators using solar light are configured such that a porous stack (solid block) is disposed in a transparent tube closed on one end thereof and thermoacoustic waves are generated by heating a portion thereof adjacent to the closed end of the transparent tube. 
         [0005]    However, in conventional thermoacoustic wave generators, to generate high-frequency thermoacoustic waves, the size of the transparent tube must be reduced inversely proportional to the frequency of thermoacoustic waves, and a high thermal gradient between both ends of the porous stack must be maintained. Therefore, in practice it is very difficult to embody such conventional thermoacoustic wave generators. Referring to the result of research so far, it has been reported that the University of Utah, USA succeeded in producing a maximum acoustic wave of 3 kHz via this conventional technique. 
         [0006]    In other words, it is no exaggeration to say that it is almost impossible to produce thermoacoustic waves in an ultrasonic wave range of 18 kHz or more using the above conventional technique. 
         [0007]    Furthermore, research on generating thermoacoustic waves has focused on generating compression waves via a process of heating a very small micro-sized structure by momentarily applying Joule&#39;s heat resulting from electric energy to the structure and then cooling the structure. This process is repeated so that air surrounding the structure is expanded and cooled. 
         [0008]    In an effort to overcome the problems of the conventional techniques pertaining to thermoacoustic wave generators, the applicant of the present invention proposed a thin metal plate membrane structure in Korean Patent Registration No. 10-1207380. 
         [0009]    However, the technique of No. 10-1207380 is problematic in that the efficiency in producing high frequency is comparatively low because some solar light transmitted through a hole is lost in the air before it reaches the membrane structure. In addition, the size of a light interrupter must be greatly increased depending on the size of the thin metal plate. Thus, it is substantially difficult to commercialize the technique. 
         [0010]    Therefore, there still is a problem in that it is difficult to substantially apply the conventional acoustic wave generator to various related industrial fields (for example, a dishwasher-related field, etc.) 
       SUMMARY OF THE INVENTION 
       [0011]    Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a dishwasher using oscillatory flow generated from thermoacoustic effect that is configured such that thermoacoustic waves having high amplitude are generated from solar energy rather than electric energy, wherein the thermoacoustic waves make oscillating waves be directly transmitted to an air column and a water column formed in a closed end of a dishwashing pipeline. In this way, high-quality energy can be directly applied to washing water, whereby energy loss can be minimized, and the washing efficiency can be markedly increased. 
         [0012]    Another object of the present invention is to provide a dishwasher including a high-frequency acoustic wave generator configured such that when a pulse beam formed by a light interrupter is directly radiated onto a porous material having a woven net or steel scrubber shape, thin wires of the porous material repeatedly rapidly thermally-expand and contract, whereby air in the space between the wires is momentarily heated and cooled, and the expansion and contraction of air is directly transmitted to an air column formed just adjacent to the porous material. By virtue of the above structure, the efficiency of the generator is markedly improved compared to the conventional technique, and the productivity is also greatly enhanced. 
         [0013]    A further object of the present invention is to provide a dishwasher including the high-frequency acoustic wave generator configured to generate high-frequency (ultrasonic) waves from obtained acoustic waves and provide the acoustic waves to a variety of industrial fields including fields pertaining to sterilization, washing, etc. 
         [0014]    In order to accomplish the above object, the present invention provides a dishwasher using oscillatory flow generated from thermoacoustic effect, including: an acoustic wave generator and a wash module. The acoustic wave generator includes: a focusing tube focusing solar light collected by a solar tracking reflector to form high-density light and emitting the focused solar light; a light interrupter including a circular disk and a rotating drive unit, the circular disk having a plurality of holes arranged at positions spaced apart from each other at regular intervals in a circumferential direction around the rotating drive unit so that solar light emitted from the focusing tube passes through the holes and thus is intermittently emitted, and a pulse beam is formed by intermittent solar light that has passed through one of the holes of the light interrupter; a housing body having a hollow tubular socket structure made of aluminum, the housing body including: an open input end through which the pulse beam enters the housing body; a space formed behind the input end, the space forming an air column; and an open output end provided behind the space; a glass cover coupled to the open input end of the housing body; a porous material provided on a rear surface of the glass cover, the porous material including a wire configured such that when the wire is thermally-expanded by the pulse beam and thermally-contracted (repeatedly deformed), the air column in the space contracts and expands, thus generating sound; and a wave guide coupled to the open output end of the housing body, the wave guide transmitting the generated sound to a desired place of use. The wash module is connected to the wave guide of the acoustic wave generator and includes: a tubular closed end configured such that when an air column vibrates, vibration having a predetermined amplitude is directly applied to a water column contained in the tubular closed end; a wash chamber connected to an open side of the closed end, the wash chamber containing washing water therein; and a transfer pipe provided on a predetermined portion of the wash chamber and connected to a desired dish washing tank. 
         [0015]    The wash module may further include at a predetermined position a heat exchanger collecting waste heat generated from the wave guide of the acoustic wave generator and supplying the waste heat to the wash chamber. 
         [0016]    In an embodiment, the input end of the housing body may have a junction surface provided with a stepped protrusion. A surface of the porous material may be formed to correspond to the junction surface. The diameter of the space having the air column may be ⅓ to ⅕ of a diameter of the input end. 
         [0017]    The porous material may be disposed in the space of the housing body. 
         [0018]    Preferably, the porous material is made of aluminum wires each of which has a diameter ranging from 0.1 μm to 1 μm and is superior in a light absorption coefficient, a thermal expansion coefficient and heat radiation performance. 
         [0019]    Furthermore, the input end of the housing body has a smaller diameter than that of a cross-sectional area of a solar light beam passing through one of the holes of the light interrupter, whereby the thermal responsiveness can be maximized. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0021]      FIG. 1  is a schematic view illustrating a dishwasher according to the present invention; 
           [0022]      FIG. 2  is a view comparing a process of removing a foreign debris or contaminant from a dish using the dishwasher with that of the conventional technique; 
           [0023]      FIG. 3  is a schematic view showing the application of an acoustic wave generator according to the present invention; 
           [0024]      FIG. 4  is a sectional view illustrating an embodiment of the acoustic wave generator according to the present invention; and 
           [0025]      FIG. 5  is a sectional view illustrating another embodiment of the acoustic wave generator according to the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Hereinafter, the present invention will be described in detail with reference to the attached drawings. 
         [0027]    As shown in  FIGS. 1 through 5 , the present invention includes an acoustic wave generator  1  and a wash module  2 . 
         [0028]    The acoustic wave generator  1  according to the present invention includes a focusing tube  100 , a light interrupter  200 , a housing body  300 , a glass cover  400 , a porous material  500  and a wave guide  600 . 
         [0029]    The wash module  2  is connected to the wave guide  600  of the acoustic wave generator  1  and includes a tubular closed end  810  configured such that when an air column vibrates, vibration having a predetermined amplitude is directly applied to a water column contained in the tubular closed end  810 . The wash module  2  further includes a wash chamber  820  that is connected to an open side of the closed end  810  and contains washing water therein, and a transfer pipe  830  that is provided on a predetermined portion of the wash chamber  820  and connected to a desired dish washing tank. Preferably, the closed end is a transparent pipe made of glass. 
         [0030]    The wash module  2  further includes at a predetermined position a heat exchanger  840  that collects waste heat generated from the wave guide  600  of the acoustic wave generator  1  and supplies the waste heat to the wash chamber  820 . 
         [0031]    That is, the heat exchanger  840  includes a predetermined position thereof a conductor configured such that heat generated from the wave guide is collected via a waste heat recovery cycle and then transferred to the wash chamber in a convection or conduction manner through a thermal medium, thus enhancing the washing efficiency. 
         [0032]    The focusing tube  100  focuses solar light collected by a solar tracking reflector to form high-density light and emits the focused light. The light interrupter  200  includes a circular disk  220  and a rotating drive unit  230 . The circular disk  220  has a plurality of holes  210  that are arranged at positions spaced apart from each other at regular intervals in the circumferential direction around the rotating drive unit  230 . Solar light emitted from the focusing tube  100  passes through the holes  210  so that the solar light is intermittently applied to the housing body  300 . 
         [0033]    As shown in  FIG. 1 , the holes  210  formed at regular intervals around the perimeter of the circular disk  220  of the light interrupter  200  cause light to intermittently pass through the circular disk  220 , thus making a pulse beam. Depending on the number of holes  210  and the RPM of the circular disk  220 , the frequency of the pulse beam is determined. 
         [0034]    The housing body  300  is made of aluminum having high thermal responsiveness. A pulse beam formed by intermittently passing solar light through the holes  210  of the light interrupter  200  enters an open input end  310  of the housing body  300  having a hollow pipe shape. A space  320  forming an air column is formed behind the input end  310 . An open output end  330  is formed behind the space  320 . 
         [0035]    The glass cover  400  is coupled to the open input end  310  of the housing body  300 . 
         [0036]    The porous material  500  is coupled to a rear surface of the glass cover  400 . When wires  510  of the porous material  500  are thermally-expanded by pulse beams and thermally-contracted (repeatedly deformed), the air column in the space  320  also contracts and expands, thus generating sound. 
         [0037]    A sealer  700  for airtightness is interposed between the glass cover  400  and the porous material  500 . The reason for this is to maintain the space in the housing body  300  in a vacuum so that the thermal deformation of the wires  510  can rapidly and reliably conducted. 
         [0038]    The wave guide  600  is coupled to the open output end of the housing body  300  and configured to transmit the generated sound to a desired place of use. Preferably, the wave guide comprises a microphone. 
         [0039]    In an embodiment, the input end  310  of the housing body  300  has a junction surface  321  with a stepped protrusion  311 . A surface of the porous material  500  is formed to correspond to the junction surface  312 . The diameter of the space  320  having the air column is ⅓ to ⅕ of that of the input end  310 . 
         [0040]    That is, in the porous material  500  having a relatively large area corresponding to that of the junction surface of the input end  310 , thermal deformation of contraction or expansion is comparatively large. On the other hand, thermal deformation of the space just adjacent to the porous material  500  is relatively small. Therefore, the amplitude of the air column can be comparatively large, whereby high frequency and high decibel of sound can be generated. 
         [0041]    In another embodiment, the porous material  500  may be disposed in the space  320  of the housing body  300 . 
         [0042]    This embodiment forms a direct transmission structure between the porous material  500  and the air column, thus minimizing loss in the transmission structure. 
         [0043]    Preferably, the porous material  500  is made of aluminum wires  510  each of which has a diameter ranging from 0.1 μm to 1 μm and is superior in a light absorption coefficient, a thermal expansion coefficient and heat radiation performance. 
         [0044]    Furthermore, the input end  310  of the housing body  300  has a smaller diameter than that of a cross-sectional area of a solar light beam passing through one of the holes  210  of the light interrupter, whereby the thermal responsiveness can be maximized. 
         [0045]    Preferably, the porous material  500  is coated with black to absorb as much solar light as possible. 
         [0046]    Furthermore, the focusing tube  100  according to the present invention has a structure divided from the reflector into a plurality of focusing tubes  100 , preferably, the number of which corresponds to the number of holes of the light interrupter  200 . Connected to a converter, terminals (each of which includes the housing body, the glass cover, the porous material, the wave guide and the sealer) respectively matching with the focusing tubes are disposed at a side opposite to the focusing tubes based on the light interrupter  200 . A variety of wavelengths of light caused due to the characteristics of solar light are synchronized (integrated) with each other by the converter so that the output power is collected. 
         [0047]    In other words, although electric energy generally has a single laser pulse wavelength, solar light has a variety of wavelengths of rays including infrared rays, ultraviolet rays, etc. Given this, when solar light is input to the terminals divided into several parts, a variety of wavelengths of light are collected by the converter, whereby the output power can be increased. 
         [0048]    As described above, a dishwasher using oscillatory flow generated from thermoacoustic effect according to the present invention is configured such that when a pulse beam formed by a light interrupter is directly radiated onto a porous material having a woven net or steel scrubber shape, thin wires of the porous material repeatedly rapidly thermally-expand and contract, whereby air in the space between the wires is momentarily heated and cooled, and the expansion and contraction of air is directly transmitted to an air column formed just adjacent to the porous material. By virtue of the above structure, the efficiency of the apparatus according to the present invention is markedly improved compared to the conventional technique, and the productivity is also greatly enhanced. 
         [0049]    Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.