Abstract:
A slightly acid solution nebulizer comprises a gas generator, a reservoir device, a nebulization device and a cleaning device, wherein the gas generator generates chlorine gas by electrolyzing diluted hydrochloric acid, the reservoir device reserves water to be mixed with the chlorine gas to produce a hypochlorous acid solution, the nebulization device nebulizes the hypochlorous acid solution, and the cleaning device cleans the gas generator by leading the water reserved in the reservoir device to the gas generator after production of the hypochlorous acid solution.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (i) Field of the Invention  
         [0002]     This invention relates to a slightly acid solution nebulizer with a cleaning function which can nebulize, for example, a hypochlorous acid solution by the effect of ultrasound.  
         [0003]     (ii) Description of the Related Art  
         [0004]     A slightly acid solution such as a hypochlorous acid solution is known to have strong sterilizing and deodorizing capabilities. In the food industry and healthcare industry, hospital rooms, tableware and the like are sterilized and deodorized by use of the characteristics of the slightly acid solution. As use of the slightly acid solution has been spread, various improvements have been made on apparatuses which produce the slightly acid solution. For example, in Japanese Patent Laid-Open Publication Nos. 169842/2003 and 197689/2000, apparatuses improved to discharge the slightly acid solution over a wide range are disclosed.  
         [0005]     Although lower than the acidity of acid solution, the acidity of the slightly acid solution is higher than that of normal water. Consequently, the slightly acid solution is highly liable to corrode the apparatuses. In particular, corrosion of reservoir which reserves relatively high concentration acidic liquid which is a source for producing the slightly acid solution, e.g. diluted hydrochloric acid, is a problem. In general, when the apparatuses are used in industries, it is considered as a daily task to clean the apparatuses with a large quantity of water obtained directly from a faucet or the like, and the task is not so difficult. However, when the apparatuses are used in households, it is often difficult to use water obtained from a faucet directly on the apparatuses, and maintenance of the apparatuses is liable to become cumbersome as compared with when the apparatuses are used in industries.  
         [0000]     Patent Literature 1  
         [0006]     Japanese Patent Laid-Open Publication No. 169842/2003  
         [0000]     Patent Literature 2  
         [0007]     Japanese Patent Laid-Open Publication No. 197689/2000  
         [0008]     The present invention has been conceived to solve the above problems of the prior art. An object of the present invention is to provide a slightly acid solution nebulizer capable of cleaning a reservoir that reserves, for example, diluted hydrochloric acid.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention is a slightly acid solution nebulizer with a cleaning function which comprises: 
        a gas generator,     a reservoir device,     a nebulization device, and     a cleaning device,     wherein     the gas generator generates chlorine gas by electrolyzing diluted hydrochloric acid,     the reservoir device reserves water to be mixed with the chlorine gas to produce a hypochlorous acid solution,     the nebulization device nebulizes the hypochlorous acid solution, and     the cleaning device cleans the gas generator by leading the water reserved in the reservoir device to the gas generator after production of the hypochlorous acid solution.        
 
         [0019]     In the above nebulizer, the above gas generator may be degassed after cleaned.  
         [0020]     In the above nebulizer, the above reservoir device can be detached from the above nebulizer.  
         [0021]     In the above nebulizer, the above nebulization device may have an ultrasonic vibrator, and the ultrasonic vibrator may have a partition therearound to separate itself from the slightly acid solution.  
         [0022]     In the above nebulizer, the above nebulization device may have an ultrasonic vibrator, and the ultrasonic vibrator may have a vinyl thin film on its portion that contacts the slightly acid solution.  
         [0023]     In the above nebulizer, a lubricant may be applied between the above thin film and the above ultrasonic vibrator.  
         [0024]     In the above nebulizer, an inlet for charging the diluted hydrochloric acid into the gas generator may have a valve for preventing gas collected inside the gas generator from leaking to the outside, and the above valve may have a cross slit.  
         [0025]     In the above nebulizer, the above nebulization device may have an ultrasonic vibrator, and an upper limit sensor and a lower limit sensor may be provided that retain the amount of the hypochlorous acid solution within a predetermined range when the solution is vibrated by the ultrasonic vibrator.  
         [0026]     Since the electrolytic device can be cleaned after production of the hypochlorous acid solution, maintenance of the apparatus can be facilitated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]      FIG. 1  is an external perspective view of a main unit and a main unit cover.  
         [0028]      FIG. 2  is an external perspective view of the main unit after members detachable from the main unit are detached.  
         [0029]      FIG. 3  is a schematic front view of the internal structure of the present apparatus.  
         [0030]      FIG. 4  is a schematic side view of the internal structure of the present apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]     Hereinafter, the present invention will be described with reference to the drawings.  
         [0032]     FIGS.  1  to  4  show an ultrasonic nebulizer according to one preferred embodiment of the present invention. This apparatus  1  may be formed in a relatively small size so that it can be placed in a room of general household.  
         [0033]     The apparatus  1  can be separated into a main unit  3  and a main unit cover  5  that can be attached detachably such that it covers a portion of the upper portion of the main unit  3 .  FIG. 1A  shows an external perspective view of the main unit cover  5 , and  FIG. 1B  shows an external perspective view of the main unit  3 .  FIG. 2  shows an external perspective view of the main unit  3  with members detachable from the main unit  3  detached.  FIG. 3  is a schematic front view of the internal structure of the apparatus  1 , and FIG.  4  is a schematic side view thereof.  
         [0034]     An operation panel  11  is provided on an outer surface of the main unit  3 . A user can perform production of a hypochlorous acid solution, nebulization of a produced hypochlorous acid solution, cleaning of the nebulizer or the like, by pressing a predetermined push-button switch  13  provided on the operation panel  11 , for example. Further, the user can select the amount of a hypochlorous acid solution to be nebulized stepwise or set nebulization time by the hour, for example. In particular, cleaning of the nebulizer may be performed automatically without operation of the push-button switch by the user.  
         [0035]     A top cover  17  is provided on the top of the main unit cover  5 . By providing the top cover  17 , the user can access the internal members of the main unit, e.g. an electrolytic device  20 , a nebulization cylinder  50  and a reservoir tank  70 , easily, without detaching the main unit cover  5  from the main unit  3 . An opening  19  is formed in a portion of the top cover  17  to allow a nebulization nozzle  64  provided on the top of the nebulization cylinder  50  to be exposed therefrom.  
         [0036]     While the nebulization cylinder  50  and the reservoir tank  70  are provided such that they can be detached from the main unit  3 , the electrolytic device  20  is completely fixed to the main unit  3 . The user can attach the nebulization cylinder  50  and the reservoir tank  70  to the main unit  3  or detach the cylinder  50  and the tank  70  from the main unit  3  easily by grabbing a handle  80  and bringing up or down the cylinder  50  and the tank  70  along the installation frame  15  of the main unit  3 .  
         [0037]     To produce a hypochlorous acid solution, for example, 0.1 to 10%, 5 to 150 cc, specifically, 1.1%, 7 cc of diluted hydrochloric acid is charged into the electrolytic device  20  in advance. At that time, to prevent gas collected in the electrolytic device  20  by previous use from leaking to the outside, a rubber valve (not shown) maybe provided right underneath the electrolytic cap  25  of an inlet  26 . Further, a cross slit may be made in the rubber valve so that diluted hydrochloric acid is charged into the electrolytic device  20  easily and is hardly spilled out. The slit is also useful for preventing gas remaining in the electrolytic device  20  from leaking to the outside and making the user uncomfortable when he opens the electrolytic cap  25 .  
         [0038]     In the electrolytic device  20 , a pair of electrodes  24  are disposed, facing each other. The electrodes  24  may be formed by coating titanium with platinum, for example. Chlorine gas can be produced by electrolyzing diluted hydrochloric acid charged into the electrolytic device  20  by the electrodes  24 . The chlorine gas is then mixed with water (tap water) reserved in advance in the reservoir tank  70 . As a result, for example, a specific hypochlorous acid solution having a pH of 4.0 to 7.5 (preferably a pH of 5.0 to 6.5) and a chlorine concentration of 1 to 60 ppm (preferably 10 to 30 ppm) is produced in the reservoir tank  70 . For example, a 2-L hypochlorous acid solution can be produced from 1.1%, 7 cc of diluted hydrochloric acid.  
         [0039]     The reservoir tank  70  can be separated into a tank body  75  and a tank cover  76 . Tap water is filled in the reservoir tank  70  with the tank cover  76  removed. The reservoir tank  70  can be attached to and detached from the main unit  3  freely with the tank cover  76  secured to the tank body  75 . Upon attachment to or detachment from the main unit  3 , more specifically, when the reservoir tank  70  is detached from the main unit  3 , the tank body  75  is completely sealed by the tank cover  76  via a packing  71 . Meanwhile, when the reservoir tank  70  is attached to the main unit  3 , a tank plug  74  is moved to the tank body  75  side ( FIG. 3  shows the state of the plug  74  after moved), against the elastic force of a tank plug spring  72  provided along a tank plug shaft  73 , by the action of a vertical gating shaft  18  provided on the main unit, whereby the opening  77  of the tank cover  76  is opened. As a result, water in the reservoir tank  70  can be mixed with the outside air (gas), and the water in the reservoir tank  70  can be discharged to the outside. When the reservoir tank  70  is attached to the main unit  3 , a chlorine inlet  31  extending parallel to the vertical gating shaft  18  from the main unit side reaches the vicinity of the opening  77 . Chlorine gas produced in the electrolytic device  20  is led directly to the water in the reservoir tank  70 , via the chlorine inlet  31  and a gas feeding and cleaning solution backflowing tube  28  which connects between the chlorine inlet  31  and the electrolytic device  20 . As a result, the chlorine gas is mixed with the water in the reservoir tank  70 , whereby the water in the reservoir tank  70  is turned into a hypochlorous acid solution. Although the thus produced hypochlorous acid solution may be nebulized by use of the nebulization cylinder  50 , it is also possible that the reservoir tank  70  is detached from the main unit  3  and the hypochlorous acid solution is used as it is. To make it easy to use the hypochlorous acid solution as it is, for example, a funnel  27  mounted in a funnel mounting portion  32  (refer to  FIG. 2 ) provided on the top of the electrolytic device  20  may be attached to the plug portion  79  of the tank cover  76  to transfer the hypochlorous acid solution in the reservoir tank  70  into another container such as a PET bottle easily.  
         [0040]     Between the electrolytic device  20  and the reservoir tank  70 , an electrolytic device liquid drainage tube  29  and an electrolytic device gas exhaust tube  30  are provided, in addition to the gas feeding and cleaning solution backflowing tube  28 . These tubes  28 ,  29  and  30  are used to clean the electrolytic device  20  after production of the hypochlorous acid solution. For example, the electrodes  24  in the electrolytic device  20  which are formed by coating titanium with platinum are highly liable to corrode. For this reason, it is preferable to clean the electrolytic device  20  after production of the hypochlorous acid solution  
         [0041]     As shown in the drawing, the electrolytic device liquid drainage tube  29  is connected to a liquid outlet  78  extending from the main unit  3  to the vicinity of the opening  77  of the reservoir tank  70 . Meanwhile, the electrolytic device gas exhaust tube  30  is connected to the gas feeding and cleaning solution backflowing tube  28  via a branching section  33  provided in the middle of the tube  28 . Although it is not necessarily clear from the drawing, the front end of the electrolytic device gas exhaust tube  30  is opened to outside air in such a manner that it can be controlled by an electromagnetic valve (not shown).  
         [0042]     After production of the hypochlorous acid solution, the rotary (not shown) of pump unit  22  rotates in the direction indicated by the arrow A in the drawing, automatically or in response to an operation by the user. This rotation pushes the electrolytic device liquid drainage tube  29  in the direction indicated by the arrow A in the same drawing. As a result, diluted hydrochloric acid in the electrolytic device  20  together with other liquids is discharged from the bottom outlet  23  of the electrolytic device  20  to the reservoir tank  70  through the electrolytic device liquid drainage tube  29  and the liquid outlet  78 . Meanwhile, in the gas feeding and cleaning solution backflowing tube  28 , the hypochlorous acid solution in the reservoir tank  70  flows backward, in response to the rotation of the rotary (i.e. in response to discharge of the liquid from the electrolytic device  20  to the reservoir tank  70 ). The backflowed hypochlorous acid solution drips to the electrolytic device  20  from above the electrodes  24  via the gas feeding and cleaning solution backflowing tube  28 . Thus, by rotating the rotary of the pump unit  22 , high concentration diluted hydrochloric acid in the electrolytic device  20  can be discharged from the electrolytic device  20  via the electrolytic device liquid drainage tube  29 , and low concentration diluted hydrochloric acid (hypochlorous acid solution) in the reservoir tank  70  can be taken into the electrolytic device  20  via the gas feeding and cleaning solution backflowing tube  28 . As a result, acidity of the inside of the electrolytic device  20  is reduced; that is, the inside of the electrolytic device  20  is cleaned. After completion of these cleaning operations, the electrolytic device gas exhaust tube  30  is opened by the action of the electromagnetic valve, and the pump unit  22  is operated to discharge diluted hydrochloric acid (hypochlorous acid solution) collected inside the electrolytic device  20  and the gas feeding and cleaning solution backflowing tube  28  to the outside. Thereby, when electrolysis is conducted next time, diluted hydrochloric acid does not spill out of the electrolytic device  20  and the concentration does not change with respect to a specified value when diluted hydrochloric acid is added.  
         [0043]     A nebulization unit for nebulizing a hypochlorous acid solution in the air primarily comprises the nebulization cylinder  50 , an ultrasonic vibrator  55 , and an air blowing section  61 .  
         [0044]     The nebulization cylinder  50  can be attached to and detached from the main unit  3  freely, and its base is formed as a rectangular frame  65  in accordance with the installation frame  15  of the main unit  3 . When the nebulization cylinder  50  is mounted on the main unit  3 , a little gap  14  is formed between the rectangular frame  65  and a main unit bottom  12  on the tank side. A hypochlorous acid solution having flowed out of the reservoir tank  70  via the opening  77  of the tank cover  76  flows on a main unit inclined plane  35  and then flows and pools in a main unit bottom  16  on the nebulization cylinder side which is lower than the main unit bottom  12  on the tank side through the gap  14 .  
         [0045]     The level of the hypochlorous acid solution pooled in the vicinity of the main unit bottom  16  can be detected by a lower limit float switch  52  and an upper limit float switch  53 . When the level of the hypochlorous acid solution exceeds limits set by the lower limit float switch  52  and the upper limit float switch  53 , in other words, when the amount of the hypochlorous acid solution is too small or too large, a predetermined signal is sent to a user, and the level of the solution is also adjusted automatically. Further, the lower limit float switch  52  that serves as a lower limit sensor is useful for preventing the ultrasonic vibrator  55  from being broken by its own vibration when the nebulizer is operated without the hypochlorous acid solution, and the upper limit float switch  53  that serves as an upper limit sensor is useful for preventing the hypochlorous acid solution from flowing out over the installation frame  15  of the main unit  3 . By keeping the upper and lower limits of the level of the solution and keeping the solution level within a predetermined range by using these lower limit float switch  52  and upper limit float switch  53 , the slightly acid solution can be retained in such an optimum amount that the nebulization cylinder  50  operates efficiently.  
         [0046]     Upon nebulization, the hypochlorous acid solution pooled in the main unit bottom  16  is subjected to ultrasound generated by the ultrasonic vibrator  55 . By the effect of the ultrasound, fine particles of the hypochlorous acid solution are produced from the surface of the solution. Then, these fine particles are turned into mist by blast airstream generated in the air blowing section  61 . The ultrasonic vibrator  55  is housed in a case  60  which is provided under the main unit bottom  16  such that its perimeter is supported by a packing  59 . In addition, the perimeter of the case  60  is covered by an O ring  57 . To release heat from the ultrasonic vibrator  55 , a cooling plate  56  may be provided at a position close to the ultrasonic vibrator  55 . The ultrasonic vibrator  55  is highly liable to corrode since it is constantly exposed to water. The problem is more severe in the present invention since the present apparatus uses an acid solution. Conventional ultrasonic vibrators use a metal sheet (such as an SUS sheet) to prevent corrosion and are plated with gold or coated with fluorine to enhance corrosion resistance. However, these conventional methods do not exert sufficient corrosion resistance to a hypochlorous acid solution used in the present apparatus. Further, in addition to the problem of corrosion, the ultrasonic vibrator  55  also has a problem that when sound energy generated by the vibrator  55  is not transferred directly to a medium having mass such as water, all sound energy is concentrated on the vibrator  55  and the vibrator  55  is broken by its own action. To solve these problems, in the present invention, in at least a portion of the ultrasonic vibrator  55  which contacts the hypochlorous acid solution, a lubricant such as grease including fluorine grease and silicone grease is applied on the surface of a metal sheet (such as an SUS sheet), and a vinyl thin film such as vinylidene chloride, polyethylene or polypropylene is then applied. Thereby, corrosion resistance can be improved significantly while the reliability of the operation is maintained.  
         [0047]     Another problem associated with the ultrasonic vibrator  55  is that the hypochlorous acid solution is liable to be degraded by vibration. When the hypochlorous acid solution is vibrated, chlorine gas dissolved in the hypochlorous acid solution is released, whereby the effective chlorine concentration is lowered. To prevent this problem, it is desirable to minimize vibration of the ultrasonic vibrator  55  that is transmitted to the hypochlorous acid solution. For this reason, in the present apparatus, a circular wall  51  that matches the shape of the ultrasonic vibrator  55  is formed to surround the portion above the ultrasonic vibrator  55 . Thus, a partition is formed between the hypochlorous acid solution and the ultrasonic vibrator, and the influence of vibration of the ultrasonic vibrator  55  on the hypochlorous acid solution can be reduced.  
         [0048]     The frequency of vibration of the ultrasonic vibrator  55  is not particularly limited but is preferably relatively high frequency. For example, while the frequency of an ultrasonic vibrator used in a conventional humidifier is around 1.6 MHz, the ultrasonic vibrator  55  of the present apparatus uses a frequency of around 2.2 to 2.6 MHz (more specifically, 2.4 MHz). By use of relatively high frequency, water to be nebulized can be made fine. For example, while a general humidifier can produce water droplets of merely around 10 microns, fine water droplets of around 1 to 5 microns can be produced by use of such relatively high frequency as described above. Water droplets of this size are sufficient to reach and eliminate germs. Further, by making water droplets fine as described above, time in which the water droplets remain in the air can be increased, and the sterilizing capability is not deteriorated. Consequently, sterilization can be performed efficiently with a small amount of a hypochlorous acid solution.  
         [0049]     The fine particles of the hypochlorous acid solution which have been generated by the ultrasonic vibrator  55  are then spurted to the outside from the nebulization nozzle  64  provided on the top of the nebulization cylinder  50  as a misty hypochlorous acid solution by the action of the air blowing section  61 . The air blowing section  61  primarily comprises a DC fan  62  and a duct  63  which are disposed in the base of the main unit. Wind generated by the DC fan  62  is led to an air outlet  66  through the duct  63  and spurted from the small air outlet  66 . This airstream with the fine particles is transferred in a mist form, whereby the hypochlorous acid solution is nebulized.  
         [0050]     Finally, a description will be given to an example of use of the present apparatus. As the preparatory stage, diluted hydrochloric acid is charged into the electrolytic device  20 , and the reservoir tank  70  is filled with tap water and set in the main unit  3 . After preparation, an electric current is passed through the electrodes  24  to electrolyze the diluted hydrochloric acid in the electrolytic device  20 , thereby generating chlorine gas from the electrolytic device  20 . The generated chlorine gas is led to the reservoir tank  70  through the gas feeding and cleaning solution backflowing tube  28 , the chlorine inlet  31  and the opening  77  and mixed with the water in the reservoir tank  70 . As a result, a hypochlorous acid solution is produced in the reservoir tank  70 . The hypochlorous acid solution can be used as it is by detaching the reservoir tank  70  from the main unit  3  or can be nebulized into the air by the ultrasonic vibrator  55  and the air blowing section  61  after moved to the main unit bottom  16 .  
         [0051]     After use, the electrolytic device  20  is cleaned. This cleaning may be started automatically or in response to operation of the button by a user. First, the diluted hydrochloric acid solution (hypochlorous acid solution) remaining in the electrolytic device  20  is discharged to the outside. This is done by sending the remaining diluted hydrochloric acid solution (hypochlorous acid solution) to the reservoir tank  70  through the electrolytic device liquid drainage tube  29  connected to the bottom of the electrolytic device  20  by rotating the rotary (not shown) of the pump unit  22  in the direction indicated by the arrow A in the drawing. Along with this operation, the air pressure inside the electrolytic device  20  decreases. By the decrease in the air pressure, the liquid in the reservoir tank  70  flows back to the electrolytic device  20  through the gas feeding and cleaning solution backflowing tube  28 . As a result, the backflowed hypochlorous acid solution drips to the inside of the electrolytic device  20  from above the electrodes  24 . Since the liquid in the reservoir tank  70  has been diluted with a large amount of water, the acidity thereof is significantly lower than that of the diluted hydrochloric acid which has remained in the electrolytic device  20 . Therefore, by continuing this operation over a predetermined time, the acidity of the electrolytic device  20  can be decreased. Further, as an additional stage, gas remaining in the electrolytic device  20  may also be discharged. The rotary of the pump unit  22  is rotated even after cleaning, and an electromagnetic valve (not shown) is operated to open the branching section  33 . As a result, the hypochlorous acid solution having backflowed from the reservoir tank  70  returns to the reservoir tank  70 , whereby the electrolytic device  20  and the gas feeding and cleaning solution backflowing tube  28  can be emptied. This can prevent diluted hydrochloric acid from spilling out of the electrolytic device or prevent the concentration from changing with respect to a specified value by adding diluted hydrochloric acid when electrolysis is conducted next time.