U.S. patent application number 09/307866 was filed with the patent office on 2001-06-14 for apparatus for generating microbubbles while mixing an additive fluid with a mainstream liquid.
Invention is credited to ECKELBERRY, NICHOLAS, UEMATSU, HIDETO.
Application Number | 20010003291 09/307866 |
Document ID | / |
Family ID | 23191508 |
Filed Date | 2001-06-14 |
United States Patent
Application |
20010003291 |
Kind Code |
A1 |
UEMATSU, HIDETO ; et
al. |
June 14, 2001 |
APPARATUS FOR GENERATING MICROBUBBLES WHILE MIXING AN ADDITIVE
FLUID WITH A MAINSTREAM LIQUID
Abstract
A unitary, self-contained apparatus for generating microbubbles
using a pipe section with a constriction device for producing a
venturi effect to cause a mainstream liquid flowing under pressure
in the pipe section to draw a column of additive fluid into the
mainstream liquid from an aspiration tube for mixing with the
liquid and a turbulence part of the pipe section immediately
downstream from the constriction device. Protrusions from the
inside surface of the turbulence part of the pipe section protrude
to at least the theoretical interface between the column of
additive fluid and the surrounding mainstream liquid and preferably
beyond, where the theoretical interface is a circumference of the
column of additive fluid having a radius equal to the radius of the
inside surface of the aspiration tube.
Inventors: |
UEMATSU, HIDETO; (IRUMA
CITY, JP) ; ECKELBERRY, NICHOLAS; (LOS ANGELES,
CA) |
Correspondence
Address: |
A M FERNANDEZ
2933 MOTOR AVENUE
LOS ANGELES
CA
90064
|
Family ID: |
23191508 |
Appl. No.: |
09/307866 |
Filed: |
May 10, 1999 |
Current U.S.
Class: |
137/888 ;
366/175.2; 366/336 |
Current CPC
Class: |
B01F 25/4316 20220101;
B01F 23/23 20220101; B01F 25/4317 20220101; Y10T 137/87587
20150401; B01F 23/2373 20220101; B01F 25/3131 20220101; B01F 25/312
20220101; B01F 25/431 20220101; Y10T 137/87652 20150401 |
Class at
Publication: |
137/888 ;
366/175.2; 366/336 |
International
Class: |
F16K 011/00; B01F
005/00 |
Claims
What is claimed is:
1. Apparatus for generating microbubbles while mixing an additive
fluid with a mainstream liquid in order to enhance the blending of
said fluid with said mainstream liquid, said apparatus having: a
section of a pipe with an inlet to receive a mainstream liquid
flowing under pressure and an outlet; a constriction device affixed
to an inside tubular surface of said section of pipe between said
inlet and said outlet, thereby producing a venturi effect of
increasing the velocity of said mainstream liquid through said
constriction device in order to lower the pressure of said
mainstream liquid flowing therethrough; an aspiration tube having
an outer diameter less than an inner diameter of said pipe section,
said aspiration tube having an inlet to receive a fluid to be mixed
with said mainstream liquid and an outlet affixed inside said
section of pipe in a position centrally disposed upstream with
respect to said constriction device and proximate thereto, whereby
lowered pressure of said mainstream liquid flowing around and past
said aspiration tube through restricted space between said
aspiration tube outlet and said constriction device produces said
venturi effect of lowering the pressure of said mainstream liquid
passing through said constriction device in order to draw additive
fluid from said aspiration tube for mixing with said mainstream
liquid, said apparatus further having a turbulence part of said
section of pipe immediately downstream from said constriction
section and a plurality of staggered protuberances inside said
turbulence part of said pipe section protruding radially from the
inside surface thereof toward its axis to a point spaced from said
surface a distance equal to approximately the distance from said
pipe section to the inside surface of said aspiration tube, whereby
each of said protuberances creates a disruption of the flow of said
mainstream liquid and additive fluid, thereby to enhance a mixture
of said liquid and fluid and cause variational tensile stresses in
the flow of said mixture to generate microbubbles in said
mixture.
2. Apparatus for generating microbubbles while mixing an additive
fluid with a mainstream liquid as defined in claim 1 wherein said
constriction device is a truncated conical surface having its base
affixed to the inside surface of said pipe section for receiving
said mainstream liquid directly from said inlet of said pipe
section and having its open end downstream from said base, and
wherein said outlet of said aspiration tube is affixed to said pipe
section upstream from said proximate to said open end of said
truncated conical surface.
3. Apparatus for generating microbubbles while mixing an additive
fluid with a mainstream liquid as defined in claim 1 wherein said
constriction device comprises two semidisc baffles affixed along
their arcuate edge to the inside surface of said pipe section with
their straight edges having an arcuate cutout at their center, said
two semidisc baffles crossing at an acute angle with respect to
each other at the centers of said arcuate cutouts thereby providing
a space for said outlet of said aspiration tube affixed between
said semidisc baffles proximate said cutouts, whereby said semidisc
baffles impart a swirling motion of said mainstream liquid to
increase the velocity and decreasing the pressure of said
mainstream liquid, thereby producing a venturi effect in order for
said mainstream liquid flowing past said aspiration tube outlet to
draw additive fluid from said aspiration tube outlet.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to apparatus for generating
microspheres or microbubbles to enhance the blending of a fluid
with a mainstream liquid.
BACKGROUND OF THE INVENTION
[0002] The increasing amount of chemicals introduced into water
systems in homes and small businesses has been identified as one of
the largest sources of environmental pollution and this practice
continues to grow unabated. When chemicals are introduced into a
closed residential water system, they are most frequently
discharged directly into an overtaxed municipal waste treatment
plant after a single use. Similarly, when chemicals are added in an
open residential water system, for example an insecticide which is
added to water by mixing through a gardening hose, most of the
chemicals will eventually flow into the water table or catch basin
to be recycled into the municipal water system.
[0003] There are many prior-art devices used for mixing or
otherwise dispensing liquid chemicals in a residential or business
water system. Most of these devices are used to dispense liquid
soap, shampoo, insecticide, fertilizer or other additives in a
stream of water by means of the force of the water under pressure
through a faucet, shower head, garden hose, or the like. Some
devices allow a user to choose between a variety of additives to be
dispensed into the stream of water. Others allow the user to select
a dilution ratio of an additive to be dispensed into the water
stream. Still other devices are adaptable for use in a wide variety
of residential and commercial applications including bath, kitchen,
and garden.
[0004] All applications of the prior-art devices are primarily
concerned with achieving a higher level of convenience and ease of
use in dispensing additives in water. The prior art does not,
however, seek to enhance the efficacy of an additive in order to
allow reduction of the ratio of additive otherwise required to
accomplish a given task, thus reducing the gross amount discharged
into the municipal waste disposal system or the ground.
[0005] The present invention distinguishes itself from the
aforementioned prior art in that it is capable of increasing the
efficacy of the additive dispensed in the water, thus allowing a
reduction in the gross amount of additive used to accomplish a
given task. This increase of efficacy of an additive is made
possible by apparatus in the mixing device that generates
microspheres or microbubbles of the additive in the water stream
for greater surface contact of the additive in the water,
particularly in situations where the two fluids being mixed are
incompatible otherwise mutually repellent, such as oil and water.
It has been demonstrated that microbubble or microsphere technology
accomplishes the mixing of such incompatible fluids, without the
use of emulsifiers or other binding agents.
[0006] The present invention accomplishes this increase of efficacy
by exploiting incipient cavitation nuclei inherent in liquids and
their unique properties upon implosion, including microbubble
shockwave and ultrasound generation. Microspheres, which are
created when two liquids are combined or microbubbles, which are
created when a liquid and a gas are combined, are both defined as
bubbles having a mean diameter of under 100.mu. (0.1 mm).
Consequently, the term microbubbles sometimes used hereinafter
refers to both. The prior art has demonstrated that fluids in a
micron state will provide dramatically accelerated mutual physical
and chemical interaction with a gas or other liquid and often
attain a 30% or higher reduction in ratio of additive required to
attain a given result.
[0007] As shown in the prior art, microbubble generation arises
from the inherent presence of incipient cavitation nuclei in
liquids. Cavitation is the process whereby microbubbles form, grow,
and collapse due to pressure differentials created in a liquid.
Tremendous local energy is released when a microbubble collapses
which causes a disproportionately increased rate of physical and
chemical interaction between molecules of any additive and its
surrounding liquid. This then greatly enhances the efficacy of the
additive in the mixture.
[0008] There are four basic methods of inducing cavitation:
hydrodynamic, acoustic, optic and particle. The present invention
makes use of a hydrodynamic method produced by pressure variations
in a flowing liquid due to the geometry of the system. Cavitation
occurs when the net pressure of the flowing liquid becomes
approximately equal to the vapor pressure of the liquid.
[0009] Despite the fact that cavitation generation of microbubbles
and the generation of the associated phenomena of ultrasound and
shockwave has long been held to be particularly detrimental in
hydrodynamic systems, the commercial, medical, and scientific
communities have nonetheless begun to successfully exploit
beneficial aspects of this technology to dramatically improve
physical and chemical reactions as well as permit previously
unattainable reactions and emulsions. A wide variety of methods
have been developed by those communities to generate microbubbles
including electrically generated ultrasonic vibrations, ceramic
contact plates, cross-membranes, certain venturi configurations
with external pumps, small scale oxygen injection apparatuses, and
microbiological reactions, among others.
[0010] Commercial communities have utilized microbubble technology
to sharply improve chemical and physical reactions such as mixing,
heat exchange, flocculation, oxidation and reduction in fields as
diverse as synthetic gas production, cancer imaging, wastewater
treatment and mineral processing. Scientific and medical
communities have utilized microbubble technology to open new lines
of research in cold fusion, non-invasive surgical procedures, and
transdermal therapy, among others. However, the means used by those
communities for producing microbubbles and utilizing the beneficial
properties resulting therefrom cannot be easily adapted to home use
for a variety of reasons. For example, a pump or electrical device
is usually involved which gives rise to concerns about safety,
size, and cost that would preclude home use. Being generally highly
sophisticated in nature, these systems for production of
microbubbles present difficulties not easily overcome in the areas
of mass-market manufacturing, installation and operation and thus
are not currently available for home or other uses requiring low
cost production for mixing a fluid gas or liquid with a mainstream
liquid.
[0011] What has not been generally appreciated by the prior art is
that hydrodynamic cavitation per se is not necessarily a negative
externality that should always be avoided altogether in
hydrodynamic systems. What the present invention seeks to exploit
is that in hydrodynamic cavitation in the mainstream of a liquid,
the liquid system itself can be utilized to generate microbubbles
and its associated phenomena to achieve a variety of benefits, one
of which is the reduction of the ratio of an additive fluid to the
mainstream liquid in order to reduce the additive needed in the
mainstream liquid.
[0012] The present invention can achieve mixing at the micron level
without altering the infrastructure of a residence or small
business through the use of microbubbles. Because the present
invention can be powered solely by the pressure of a mainstream
liquid flowing from a source and utilizes no electricity, pump, or
other mechanical devices, the power of a municipal water system is
sufficient for the present invention to attain mixing of fluids in
a mainstream flow of water at a micron level, such as detergents or
chlorine, despite pressures as low as 25 PSI and low flow rates of
2.25 to 5.0 gallons per minute. Certain types of industrial static
mixers, e.g., U.S. Pat. No. 4,270,576 (Takeda), operate with
electricity, pump, or other external means and therefore cannot be
self-contained for insertion in a residential or small business
water system, such as in a clothing or dish washing system.
SUMMARY OF THE INVENTION
[0013] In accordance with the present invention, apparatus for
mixing a fluid (gas or liquid) with a liquid of a primary stream
comprises a section of pipe or tube attachable to a source of
main-stream liquid under pressure. The defined space in the section
of tube is provided with a constriction device between its inlet
and outlet for the purpose of increasing the velocity of the
main-stream flow of liquid through the constriction device and thus
lowering the pressure of the main-stream liquid at the constriction
in accordance with Bernoulli's principle. An aspiration tube having
an outer diameter substantially smaller than the inner diameter of
the tube section and having its inlet coupled to a source or
reservoir of the fluid to be mixed with the main stream of liquid
has its outlet centrally disposed upstream in the tube section and
proximate to the constriction device such that low pressure of the
main stream of liquid flowing around the aspiration tube and
through the restricted space between the aspiration tube outlet and
the constriction device produces a venturi effect so that the fluid
is drawn from the aspiration tube into the mainstream of
liquid.
[0014] The fluid drawn in from the aspiration tube will initially
form a column of fluid surrounded by liquid as the liquid begins to
decelerate. In order to promote cavitation, i.e., the formation of
microbubbles in the liquid for optimal mixing or blending of the
fluid with the liquid, staggered pins are provided that extend out
from the wall of the pipe towards its axis in a section downstream
from the constriction device. The length of these pins is chosen to
be approximately equal to the theoretical distance from the wall to
the interface of the column of fluid and the surrounding fluid.
Since that interface is not precisely defined due to the fact that
some blending will begin to occur immediately after the exit of the
fluid from the aspiration tube, the theoretical interface may be
taken at least at the center of that region of initial blending and
preferably the inner circumference of that region. The purpose of
the protruding pin is to create microscopic turbulence in the
region of blending for optimal inducement of cavitation, which is
to promote the formation and activity of microbubbles in the liquid
for maximum blending of the fluid with the mainstream liquid.
[0015] The novel features that are considered characteristic of
this invention are set forth with particularity in the appended
claims. The invention will best be understood from the following
description when read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a first embodiment of the
present invention using a straight-through flow pipe or tube
section 2 and an aspiration tube 4 in front of a flow constriction
device 3 in the form of a truncated conical surface followed by a
turbulence section 5 with protuberances 7 and a pressure reduction
section 6.
[0017] FIG. 2 is a perspective view of a second embodiment of the
invention using a constriction device consisting of two opposing
flow deflectors 11, 12 in the form of semidiscs at opposing angles
with respect to mainstream liquid flow through the tube
section.
[0018] FIG. 3 is a perspective view of another embodiment of the
invention having an alternate geometry, namely an L-shaped cylinder
or tube section, in order that the aspiration tube need not be
bent.
[0019] FIG. 4 is a perspective view of the invention shown in FIG.
1 incorporated in a sink faucet 9.
[0020] FIG. 5 is a perspective view of the present invention shown
in FIG. 1 with the aspiration tube commencing at a remote distance
from the flow constriction device and extending centrally and
coaxially through an extender tube section 10 or hose to a position
proximate the flow constriction device.
DETAILED DESCRIPTION OF INVENTION
[0021] The embodiments of the invention illustrated in the drawings
are directed to the provision of apparatus for generating
microspheres or microbubbles while mixing a fluid with a mainstream
liquid at a micron level using the mainstream liquid pressure
without the use of any other source energy, or other devices, based
on the current theories of cavitation generating microspheres or
microbubbles described as follows.
[0022] This invention exploits the presence of incipient cavitation
nuclei present in liquids. That nuclei, when stretched,
subsequently collapses and produces the phenomenon known as
cavitation that results in microspheres or Microbubbles. Cavitation
occurs when variational tensile stresses are superimposed on the
prevailing ambient pressure of a flowing liquid such that the total
net pressure becomes approximately equal to the vapor pressure of
the liquid. While there exist alternative theories that might also
explain this cavitation reaction, hydrodynamic cavitation seems to
be the most appropriate explanation underlying the effects produced
by the present invention.
[0023] Referring now to FIG. 1, which shows a detailed perspective
view of a first embodiment of the present invention comprising a
straight-through section of pipe or tube 2 which can be made from a
variety of inexpensive materials and which is installed or attached
by a coupler 1 to the end of or within a standard plumbing fixture
or configuration (not shown) such as a water tap, faucet,
showerhead, garden hose, washing machine water hose, dishwasher
water hose, or the like, the mainstream liquid flowing through the
tube 2 and comes into contact with a flow constriction device 3 in
the form of a truncated conical surface oriented so that the liquid
must pass through the base thereof (having a diameter equal to the
diameter of the tube 2) and out of the open top thereof, the
diameter of which open top is less than the diameter of the tube 2,
thereby creating a venturi effect as the liquid passes
therethrough. That in turn creates a progressively decreasing
pressure zone within the constriction device 3 which draws a fluid
out of an aspiration tube 4, having an outer diameter substantially
smaller than the inner diameter of the tube 2 and having an outlet
disposed centrally and coaxially with respect to the tube 2
proximate the constriction device 3, somewhere between the base and
open top thereof. The mainstream liquid entrained with fluid and
ambient air drawn from the aspiration tube 4 mix as they enter a
reaction chamber 5. A central high pressure liquid jet created by
the constriction device 3 is located at the core mix entering the
reaction chamber 5.
[0024] The fluid flow through the aspiration tube 4 is not intended
to be present at all times. Instead, an on/off valve (not shown) is
momentarily turned on such that ambient air (trapped in the
aspiration tube until the valve is turned on) will be entrained
with the fluid to be mixed. Entrained air does not have any adverse
effect on the operation of the invention but rather is believed to
aid in the generation of microbubbles. On the other hand, its
presence is not deemed to be critical.
[0025] It is believed that the additive fluid enters the reaction
chamber 5 in a column with the mainstream liquid swirling around
the column of additive fluid, but whether or not the liquid is
swirling, it is known to be surrounding the column of additive
fluid. Fluids not already mixed around that central column of
additive fluid tend to move outwardly towards the mainstream liquid
as the column expands and come into contact with a plurality of
protuberances 7 that protrude into the core of additive fluid.
Collision of the liquid with the protuberances 7 creates a number
of vortices and low and high pressure zones whereby transient and
incipient cavities inherent to the fluids being mixed are stretched
and pulled. Upon exit from the reaction chamber 5, the fluids with
stretched cavities enter a downstream zone 6 of the tube 2, defined
by the absence of any protuberances, where the stretched cavitation
nuclei collapse or implode onto each other causing the phenomenon
known as cavitation followed by the production of microspheres
accompanied by shockwaves. The microspheres flowing out of the zone
6 explode, thereby completing a thorough mixture of liquid and
additive fluid and in the process producing ultrasound waves.
[0026] Although FIG. 1 shows a typical embodiment of the present
invention, it will be appreciated that variations in the overall
design geometry of the apparatus, as well as variations in the flow
constriction device configuration and the protuberances will occur
to those skilled in the art.
[0027] FIG. 2 illustrates an alternate flow constriction device to
be compared and contrasted to that of FIG. 1. In FIG. 2 the flow
constriction device 3 is in the form of a three-dimensional surface
of a truncated cone coaxially attached to the wall of the tube 2,
as shown, with its central opening at the top sufficiently small as
to cause a venturi effect of increasing the velocity of the main
stream liquid flow therethrough as its pressure is reduced with the
maximum reduction of pressure at the outlet opening, thus allowing
the mainstream of liquid to effectively "draw" fluid at a higher
pressure from the aspiration tube 4 as the mainstream liquid passes
through the constriction device 3. In contrast, the flow
constriction device 3' in FIG. 2 comprises two semidisc flow
constriction panels 3a, 3b positioned at an acute angle to each
other and attached to the wall of the tube 2, thus leaving a
restricted space between the panels to permit the mainstream of
liquid and entrained fluids to pass therethrough with a swirling
motion since flow restriction panels 3a and 3b impart circular
deflection to the flow with attendant increase in velocity and
decrease in pressure of the mainstream liquid and entrained fluids.
It is to be understood, however, that such flow constriction
devices shown in FIG. 1 and FIG. 2 are for illustrative purposes
only, and that other flow constriction devices of different design
or shapes can be used to accomplish the aforementioned creation of
the venturi.
[0028] FIG. 3 illustrates an alternate overall design geometry of
the apparatus wherein the tube 2' is L-shaped. An advantage of the
L-shaped tube 2' is that the aspiration tube 4' is then straight so
there is no restriction to the flow of additive fluid and entrained
air. Although the L-shaped tube 2' results in a slight decrease in
the overall flow rate of the system, it would not noticeably alter
the effectiveness of the apparatus.
[0029] In both embodiments, the space between the tips of the
opposing protuberances is preferably equal to the inner diameter of
the aspiration tube 4. In the embodiment of FIG. 1, the outlet of
the aspiration tube is spaced upstream from the constriction device
3 and has an inner diameter less than the diameter of the
downstream opening of that constriction device, both of which serve
to allow the fluid being aspirated and the mainstream liquid to
flow with the fluid flowing in a column surrounded by the
mainstream liquid. The protuberances 7 are selected to be of a
length sufficient to at least extend through the outer layer of the
mainstream liquid to the inner column of fluid and preferably
slightly into the column of fluid. Consequently, an acceptable
criterion is a protuberance length approximately equal to the
distance from the inner surface of the tube 2 to the inner surface
of the aspiration tube 4 at the outlet thereof.
[0030] The same criterion applies in the embodiment of FIG. 2 where
the constriction device is comprised of two semidiscs 3a and 3b
which together impart a swirl in the downstream flow of the
mainstream liquid and at the same time produces a low pressure area
inside the swirl as the velocity of the liquid increases. The low
pressure inside the swirl then draws a column of additive fluid
into the tube 2 downstream of the constriction device semidiscs. In
this case, the swirling mainstream liquid surrounding the additive
fluid will tend to confine the additive fluid to a column having a
diameter equal to the inside diameter of the aspiration tube
outlet. However, the greater velocity of the swirling liquid
produces a shearing stress at the interface between the column of
additive fluid and the swirling mainstream liquid. This adds to the
tensile stress in the transient cavities, thus promoting greater
hydrodynamic cavitation. Nevertheless, the protuberances should
meet the same criterion as in the first embodiment shown in FIG. 1,
i.e., should extend at least through the swirling mainstream liquid
and preferably into the column of additive fluid.
[0031] In general, for purposes of the present invention, the
design of the solid protuberances may take a variety of shapes. For
instance, an inverted polygonal column or tetragonal pyramid may be
used to provide or induce the formation of a series of high and low
pressure zones in the reaction chamber 5 through which the flow
stream passes to produce turbulence without any deviation from the
spirit and scope of the present invention, thereby promoting the
cavitation of fluids passing through reaction chamber 5. Similarly,
the placement of staggered protuberances along the inner wall of
reaction chamber 5 may be either zigzagged along lines parallel to
the tube axis along circular lines around that axis or both. The
objective is to use an arrangement of protuberances which provide
maximum turbulence by collision with protuberances. Thus, a
multitude of low and high pressure zones affecting the fluids
(additive fluid and air) and mainstream liquid being mixed are
created as they pass through the reaction chamber 5. That enhances
cavitation that is followed by the creation of microspheres which
in turn maximizes the mixing of additive fluid (liquid or gaseous
and entrained air) with the mainstream liquid.
[0032] As shown in FIG. 1, FIG. 3, and FIG. 5, the position and
design of aspiration tube 4 may easily be modified to adapt it to
various overall system design considerations relating to
application constraints that require an extender 10 for the tube 2,
provided that the inlet of the aspiration tube 4 commences at a
point upstream from the constriction device 3 and the outlet of the
aspiration tube 4 is aligned with the center line of the
constriction device 3 and between a plane at the front of the
constriction device (defined by its circumference connected to the
tube wall) and the opening at the outlet thereof to allow some
significant space for flow of mainstream liquid from the inlet of
the tube 2 but preferably at the front plane of the constriction
device. It will also be appreciated by those skilled in the art
that the aspiration tube 4 can be used in conjunction with any
number of available additive fluid dispensing systems, including
multiple fluid dispensing systems, as the aspiration created by the
venturi-effect of the constriction device is strong enough to draw
but the most viscous fluids into the apparatus. Additionally, it
will be appreciated by those skilled in the art that other
configurations for additive fluid introduction systems may readily
occur to those skilled in the art without significantly altering
the spirit or results of the present invention.
[0033] Although a description of the present invention has been
illustrated in various configurations, and one application has been
illustrated in connection with a sink faucet, it should be
appreciated that the invention may be adapted to many medical and
scientific applications as well as other residential applications,
and although particular embodiments of the invention have been
described and illustrated herein, it is recognized that
modifications may readily occur to those skilled in the art.
Consequently, it is intended that the claims be interpreted to
cover such modifications and equivalents thereof.
* * * * *