Aerator for generating fine bubbles by supersonic wave action

This invention is directed to an aerator device and method for generating fine bubbles from a liquid and gas mixture. In particular this invention is directed to aeration of liquid to generate fine bubbles for industrial as well as for domestic use.

BACKGROUND OF THE INVENTION 
Heretofore the production of liquid bubbles has been achieved by various 
known methods including mechanically stirring or agitating the liquid 
surface, ejection of air into the liquid, and suction of air into the 
liquid by a reduced pressure action by ejecting liquid at high velocity. 
In recent developments these aeration methods have been favorably regarded 
for use in a gas-liquid contact device or for an aeration device, but were 
not fully satisfactory from the point of efficiency, e.g., available data 
showed that the practical use of known aeration devices amounted to only 
about 9% of the total oxygen output. 
Consequently, applicant conducted extensive research to produce a more 
effective aeration device and as a result has discovered that supersonic 
wave is generated when liquid is ejected at high velocity and air is mixed 
into the motive fluid flow to form bubbles, and successfully reduced this 
invention to practice by effectively utilizing supersonic wave. 
With the foregoing in mind, one object of this invention is to provide an 
aeration device capable of forming fine bubbles using supersonic wave 
action. 
Another object of this invention is to provide an aeration device that 
effectively produces an aerated motive fluid flow adaptable to a wide 
range of uses. 
A further object of this invention is to provide warming, vibrating and 
germicidal actions by effectively producing an air-liquid contact. 
It is yet another object of this invention to effect sterilization by water 
treatment of active sludge by supersonic wave action. 
It is moreover an object of this invention to effect motive fluid flow by 
supersonic wave action for use in washing with water. 
It is furthermore an object of this invention to supply water for a warm 
bath, face washing, or massage by supersonic wave action. 
Other objects, benefits, and advantages of this invention will be readily 
appreciated upon reading the remainder of this specification and 
considering the structure illustrated in the accompanying drawing. 
SUMMARY OF THE INVENTION 
With the foregoing in mind the reader will readily appreciate the concept 
of the instant invention which utilizes supersonic wave action developed 
in a liquid when bubbles are generated in an apparatus and are destroyed 
or crushed as the bubbles collide or dash against wall portions of the 
apparatus. It will be clear that according to the present invention fine 
bubbles are produced in motive fluid flow with a supersonic wave 
atmosphere in an aerator. While the basis for the development of the 
foregoing is not entirely clear, stepped up activity of molecular movement 
between liquid and air due to supersonic wave action or reduction in 
surface tension of the liquid as a result of supersonic wave vibration are 
offered as possible explanation of the phenomenon. Also, as supersonic 
wave is known to produce excitation of the molecules, and contact 
establishes an excited condition when the present invention is used as an 
air-liquid contact device, especially an air-liquid contact device in 
which a small amount of air is brought into contact with the liquid, or by 
using it as an aeration device. Therefore, in addition to providing an 
improved contact frequency, the present invention also improves 
effectiveness by supersonic wave. Moreover, as supersonic wave possesses 
warming, cleansing, vibrating and germicidal actions, the present 
invention develops these characteristics in the sterilization of liquid, 
for example, in an effective sterilization treatment of activated sludge. 
Further, the present invention may be effectively used for cleansing 
action by spurting or jetting the cleaning fluid. Still another use of the 
present invention is its use in effectively warming, washing, and 
massaging and bathing the human body. 
Additional advantages of the present invention reside in the simplicity of 
the structure of the aerator, and its ability to effect a jet or spurt 
without wasting large amounts of water which considerably broadens the 
range of industrial use. Also, this invention makes it possible to produce 
fine bubbles by providing a lower .DELTA.P or pressure differential as 
compared to the known methods of subdividing the formed bubbles with a 
filter.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now in detail to the drawings and with particular attention to 
FIG. 1, the reader will readily appreciate that an aerator apparatus is 
illustrated with a casing 1; having an air inlet or vent 2 shown to be in 
the form of a tube; a nozzle 3 through which motive liquid may be 
introduced; a lid 4 secured at the top of casing 1; and outlet 5; and a 
body 6 defining cavity or chamber 16 with a plurality of pores 7 in the 
wall of resonating body 6. As may be clearly seen in FIG. 1, an aerator 
apparatus according to the present invention comprises a casing 1 with 
nozzle 3 for liquid at the bottom of casing 1 and fluid outlet 5 for 
aerated motive fluid flow disposed at the top of lid 4. Resonant body 6 is 
seen to extend between nozzle 3 and fluid outlet 5 to provide a passage 
therebetween. Resonant body 6 is further seen to be located generally 
centrally of the interior of casing 1 at a substantial space away from the 
wall of casing 1. Resonant body 6 is further seen to extend in surrounding 
relationship around the outlet end of nozzle 3 and the inner end of outlet 
5. Air inlet vent 2 extends through a side wall portion of casing 1 
whereby air may be introduced into the casing 1 in the space around 
resonant body 6. 
Use of the aerator apparatus of FIG. 1 is achieved by introducing liquid 
through nozzle 3 which is effused from nozzle 3 into resonating cavity or 
chamber 16, while at the same time air inlet allows air to be drawn into 
casing 1 from the atmosphere or an air chamber which may be built and/or 
mounted on casing 1. As a plurality of pores 7 are seen to extend 
transversely through the wall of resonant chamber 6, it is clear that as 
motive fluid is effused from nozzle 3 into resonant chamber 16 air 
introduced into casing 1 through inlet vent 2 will naturally be drawn into 
chamber 16 through pores 7 to form bubbles by mixing with the motive fluid 
in resonant chamber 16 to produce aerated liquid which is then ejected 
from casing 1 through outlet 5 with fine bubbles in a spurt or jet. The 
numerous pores 7 as illustrated in FIG. 1 are to be understood to extend 
through the wall of resonant body 6 in a circumferential pattern along the 
entire length thereof. 
The alternative embodiment of the present invention illustrated in FIG. 2 
comprises lid 4 and the resonant body 6 as an integral member with the 
lower part of the resonant body 6 formed as a taper surface, and the 
numerous pores 7 each connected in series to a hollow part of the tube's 
taper surface. The resonant body 6, however, may be constructed with a 
smaller diameter than the inner circumference of the casing 1 which is 
quite different from the structure illustrated in FIG. 2 and may be 
suspended from lid 4. The pores 7 are open at opposite ends thereof and 
extend at a fixed angle to the axis of the resonant cavity 16 and as seen 
in FIG. 2 to be oblique, in contrast to the pores 7 in the embodiment of 
FIG. 1 in which such pores 7 are perpendicular to the axis of the resonant 
cavity 16. The frequency or number of cycles of the supersonic wave 
generated by the aerator of FIG. 2 may be altered by altering the angle of 
pores 7. The diameter of these pores 7 may be suitably designed to produce 
a desired range of supersonic wave together with the ejection speed of the 
liquid. Further, according to the embodiment of aerator illustrated in 
FIG. 2, when the liquid flow from nozzle 3 is ejected toward the outlet 5 
within the resonant cavity 16, a reduction in the pressure occurs in the 
numerous pores 7 due to the effusion of the liquid flow and air is sucked 
within the resonant cavity 16 by way of pores 7 from air inlet 2. Thus, 
this air forms bubbles by being mixed within the ejected motive fluid flow 
and produce aerated motive fluid flow and the aerated current jets out 
from outlet 5. Also, when the air mixes with the motive fluid flow through 
the pores 7, the air current becomes turbulent and each of the pores 7 in 
the wall of resonant body 6, as well as the resonant cavity 16 itself, 
becomes a resonant cavity and generates supersonic wave, and forms bubbles 
under supersonic wave atmosphere. Even though no mention has been made on 
the experimental production of resonant body 6 using synthetic resin and 
metal, the former produced less supersonic wave, while the latter 
generated many times the number of high frequency waves; the latter 
generated supersonic wave by the resonant action with said resonant body 6 
and it is evident that the harder the material for the resonant body 6, 
the greater the advantage. The resonant body 6 illustrated in FIG. 2 
includes a generally cylindrical inner or cavity surface and a conical or 
tapered outer surface, which diverges in the direction from nozzle 3 
toward outlet 5 so that different flow patterns and mixing characteristics 
from that of the embodiment of FIG. 1 may be obtained. In addition, there 
was some difference in the generation of supersonic wave depending on the 
material used for the casing 1, but effective supersonic wave can be 
generated by building the entire casing 1 or only the inner surface 
thereof with hard material such as metal due to the deflection and 
absorption of the supersonic waves. The aerator of this invention produces 
fine bubbles since bubbles are formed in the motive fluid flow with 
supersonic wave atmosphere as explained above. While the principle of the 
invention is not completely clear, it is believed that the activation of 
the molecular movement between the liquid and the air due to the 
supersonic wave vibration, or due to the reduction in surface tension of 
the liquid owing to the supersonic wave vibration is the basis thereof. 
While the invention has been described with reference to particular 
embodiments thereof, it is to be understood that modifications may be made 
by persons skilled in the art without departing from the spirit of the 
invention or from the scope of the invention defined in the appended 
claims.