U.S. patent application number 09/908315 was filed with the patent office on 2001-11-15 for water purifier system.
This patent application is currently assigned to OZONAID INTERNATIONAL, INC.. Invention is credited to Wang, Desheng.
Application Number | 20010040133 09/908315 |
Document ID | / |
Family ID | 23653970 |
Filed Date | 2001-11-15 |
United States Patent
Application |
20010040133 |
Kind Code |
A1 |
Wang, Desheng |
November 15, 2001 |
Water purifier system
Abstract
Ozone is generated and combined with water. The combined water
and ozone are then mixed to provide a substantially homogeneous
mixture which subsequently is transported along a confined flow
path having a length sufficient to provide substantially complete
decomposition of the ozone.
Inventors: |
Wang, Desheng; (Pasadena,
CA) |
Correspondence
Address: |
Thomas R. Lampe
BIELEN, LAMPE & THOEMING
Suite 720
1990 N. California Blvd.
Walnut Creek
CA
94596
US
|
Assignee: |
OZONAID INTERNATIONAL, INC.
|
Family ID: |
23653970 |
Appl. No.: |
09/908315 |
Filed: |
July 17, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09908315 |
Jul 17, 2001 |
|
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09417421 |
Oct 13, 1999 |
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Current U.S.
Class: |
210/739 ;
210/760; 210/763 |
Current CPC
Class: |
C01B 13/11 20130101;
C02F 1/78 20130101; C01B 2201/14 20130101 |
Class at
Publication: |
210/739 ;
210/760; 210/763 |
International
Class: |
C02F 001/78 |
Claims
1. Water purifier apparatus comprising, in combination: an ozone
generator; a source of water; fluid combining means for receiving
ozone from said ozone generator, for receiving water from said
source of water and for introducing said ozone into said water;
fluid mixer means for mixing the water and ozone received by said
fluid combining means to provide a substantially homogeneous
mixture of water and ozone; and fluid flow path defining means
forming a confined flow path for receiving the substantially
homogeneous mixture of water and ozone from said fluid mixer means,
said confined flow path having a length sufficient to provide
substantially complete decomposition of the ozone in the
substantially homogeneous mixture of ozone and water passing
therethrough, said fluid flow path defining means having an exit
for water in the confined flow path after substantially complete
decomposition of the ozone in the substantially homogeneous mixture
of ozone and water has occurred.
2. The water purifier apparatus of claim 1 wherein said fluid mixer
means comprises at least one inline static mixer providing
substantially complete transverse mixture uniformity with minimal
longitudinal mixing of the combined water and ozone passing through
the fluid mixer means.
3. The water purifier apparatus according to claim 1 additionally
comprising a catalyst holder having an inlet and outlet and
defining a holder interior accommodating at least one catalyst,
said catalyst holder being located downstream from said fluid mixer
means and for receiving said substantially homogeneous mixture of
water and ozone from said fluid mixer means.
4. The water purifier apparatus according to claim 1 wherein said
fluid combining means includes an ozone diffuser for receiving
ozone from said ozone generator and for forming ozone bubbles
introduced into said water.
5. The water purifier apparatus according to claim 4 wherein said
ozone diffuser comprises a porous body into which said ozone is
introduced under pressure.
6. The water purifier apparatus according to claim 1 additionally
comprising water filter means for receiving water from said source
of water and filtering said water prior to introducing ozone into
said water.
7. The water purifier apparatus according to claim 6 wherein said
water filter means comprises an activated carbon filter upstream
from said fluid combining means.
8. The water purifier apparatus according to claim 1 additionally
comprising a water sensor downstream from said source of water to
detect the presence of water in the apparatus at a location
upstream from said fluid combining means and for energizing said
ozone generator in response thereto.
9. The water purifier apparatus according to claim 8 additionally
comprising an air compressor for introducing compressed air into
said ozone generator, said water sensor energizing said air
compressor responsive to detecting the presence of water in the
apparatus at a location upstream from said fluid combining
means.
10. The water purifier apparatus according to claim 1 additionally
comprising a filter operatively associated with said fluid flow
path defining means for receiving water passing through the exit of
said fluid flow path defining means and for filtering said
water.
11. The water purifier apparatus according to claim 1 additionally
comprising a flow meter for measuring the flow of water through the
apparatus.
12. The water purifier apparatus according to claim 10 wherein said
fluid flow path defining means comprises an outer housing segment
defining an interior and an inner housing segment positioned in the
interior of the outer housing segment, said inner and outer housing
segments forming a helical fluid flow path.
13. The water purifier apparatus according to claim 12 wherein said
inner housing segment defines a chamber receiving a water
filter.
14. The water purifier apparatus according to claim 13 wherein said
water filter is an activated charcoal filter.
15. The water purifier apparatus according to claim 13 wherein the
exit of said fluid flow path defining means is in fluid flow
communication with said chamber.
16. The water purifier apparatus according to claim 1 wherein said
ozone generator defines a passageway for receiving water from said
fluid flow path defining means and for directing said water through
said ozone generator to cool said ozone generator.
17. The water purifier apparatus according to claim 16 wherein said
ozone generator includes two spaced, coaxial, cylindrically-shaped
electrodes having an annular air space therebetween, said water
purifier apparatus additionally comprising an air compressor for
introducing air under pressure into said annular air space, said
ozone generator defining an inlet and outlet communicating with
said space, air from said air compressor entering said inlet, and
ozone exiting said chamber through said outlet and flowing to said
fluid combining means.
18. A method of purifying water, said method comprising the steps
of: generating ozone; introducing the ozone into water; after the
step of introducing the ozone into water, mixing the water and
ozone to provide a substantially homogeneous mixture of water and
ozone; introducing the substantially homogeneous mixture of water
and ozone into a confined flow path; and flowing the substantially
homogeneous mixture of water and ozone in said confined flow path
for a period of time sufficient to provide substantially complete
decomposition of the ozone in the substantially homogenous mixture
of ozone and water so that no offgas ozone destruction is required
after the water from the substantially homogenous mixture of ozone
and water exits said confined flow path.
19. The method according to claim 18 wherein said mixing step
comprises flowing the water and ozone past at least one inline
static mixer to provide substantially complete transverse mixture
uniformity with minimal longitudinal mixing of the combined water
and ozone.
20. The method according to claim 18 including the step of passing
the substantially homogenous mixture of water and ozone through at
least one catalyst to absorb bacteria and viruses in the
substantially homogenous mixture.
21. The method according to claim 18 wherein the step of
introducing the ozone into the water is carried out by introducing
the ozone in bubble form into the water.
22. The method according to claim 21 wherein the ozone is converted
into bubble form by pressurizing the ozone and passing the
pressurized ozone through a porous body in the water.
23. The method according to claim 18 including the step of
filtering the water before the step of introducing ozone into the
water.
24. The method according to claim 18 including the step of
filtering the water after the ozone in the substantially homogenous
mixture of ozone and water has substantially completely
decomposed.
25. The method according to claim 18 including the step of
measuring water flow.
26. The method according to claim 18 including the step of
directing water exiting said confined flow path through an ozone
generator employed to carry out said step of generating ozone to
cool the ozone generator.
Description
TECHNICAL FIELD
[0001] This invention relates to drinking water purification. The
apparatus and method of the invention provide bacterial
disinfection, viral inactivation and oxidation of organics. The
invention encompasses an economical, lightweight, and compact ozone
water purification system that is safe, reliable, effective, and
convenient, economical to operate and maintain, and suitable for
household use.
BACKGROUND OF THE INVENTION
[0002] The 1986 Amendments to the United States Safe Drinking Water
Act required the U.S. Environmental Protection Agency to implement
regulations requiring disinfection of all public water supplies.
The regulations also specified water quality criteria under which
filtration of surface waters would be a requirement and listed
Giardia Lamblia and viruses among a list of 83 contaminates that
would be regulated in drinking water. Ozonation is one of many
methods used for the purification of water. It is a technology
substantially more effective than others. Ozone not only can kill
bacteria and viruses, but also oxidize organics such as detergents,
pesticides, herbicides, phenols and inorganics such as iron,
manganese, organically bound heavy metals, cyanides, sulfides, and
nitrates. Ozone has been used to treat ground and surface water in
many European cities for years and also is becoming the industry
standard for treating bottled water.
[0003] Ozone, also referred to as triatomic oxygen, is an unstable
gas having life in water of minutes. Oxygen, which is normally
bi-atomic, becomes ozone through the addition of a third unstable
atom. Ozone, because of its instability, cannot be generated and
stored for future use. It must be generated and used for treatment
immediately. It is created by one of two generation methods:
ultraviolet radiation or corona discharge. Of the two, corona
discharge produces the substantially higher ozone concentration
needed for the removal of complex impurities. Generated ozone is
pumped into the water through an ozone diffuser, a stone of fine
porosity, creating very small bubbles which rise slowly through the
water. The slower the bubbles rise through the water, the greater
the amount of ozone transferred to the water.
[0004] Most critically for water quality, ozonation does not add
chemicals to the water as does chlorine, chlorine dioxide,
permanganate, etc. As the ozone passes through the water, the third
unstable atom detaches, attacks, and destroys impurities in the
water. The residue in the water is pure oxygen, which quickly
dissipates. Any excess ozone which is not needed for treatment
reverts to simple oxygen.
[0005] Two main schemes for ozone reactions in water have been
proposed (see J. Hoigne and H. Bader. 1975. Ozonation of Water:
Role of Hydroxyl Radicals as oxidizing Intermediates. Science,
190(4216): 782-784). The first is direct oxidation, which is a
selective oxidation of chemical compounds by the ozone molecule.
These reactions are quite selective and can take minutes. In the
absence of ozone decomposition, the ozone concentration can remain
relatively constant over short time intervals. The second scheme
relates to oxidation by intermediate radical species where the
hydroxyl radical is believed to be the most important of the ozone
decomposition products. The hydroxyl radical is highly reactive and
has a life span of only a few microseconds in water. The mode of
action of ozone on microorganisms is poorly understood. Some
studies using bacteria suggested that ozone altered proteins and
unsaturated boned of fatty acids in cell membrane, leading to cell
lysis. Other studies have suggested that ozone may affect
deoxyribonucleic acid (DNA) in the cell, causing cell inactivation.
Virus inactivation was reported to be related to attack of protein
capsid by ozone.
[0006] The ability of ozone to disinfect polluted water was
recognized as early as 1886. Ozonation might have become universal
for disinfection in water treatment except for the introduction of
cheap chlorine gas. Recently, however, concern has been expressed
about possible toxic effects of chlorine to human health. In search
for alternatives to chlorine, ozone is being considered.
[0007] Ozone is toxic and dangerous to human, animal and plant
life, including aquatic forms. Conventional bottled drinking water
production systems consist of three major components: the ozone
generator, ozone water mixer and offgas ozone destroyer. Although
bottled drinking water is disinfected by ozonation, it is still
quite possible that the bottled drinking water can be polluted by a
secondary contamination occurring during sealing, transporting,
storing and using the product. It is known that bacteria and
viruses multiply fast, especially when bacteria and virus
inhibiting substances are removed from bottled drinking water.
Sometimes the level of bacteria and viruses in bottled drinking
water actually may be higher than that of tap water if the bottled
drinking water is stored for a long time.
[0008] Ideally, it is better to drink fresh, bacteria free, clean
water. Therefore, an effective ozone water purifier suitable for
household use is highly desirable. In an industrial bottled
drinking water production system, the design of ozone water mixer
and offgas ozone destroyer is relatively easy because there is no
space limitation. However, for small ozone water purifiers suitable
for household use, designing a compact device is not simple without
sacrificing the quality of purified drinking water. In a thermal
ozone destruction unit, the offgas is heated to a prescribed
temperature, typically between 300.degree. C. and 350.degree. C.
for a short period of time. Such a unit can not be employed in a
compact ozone water purifier suitable for household use. Major
components of household devices and appliances are often made of
plastics for economic and other reasons, and these materials
usually cannot withstand such high temperatures.
[0009] In ozonation systems disinfection efficiency depends on the
dose of ozone injected in water, ozone and water mixing, ozone and
water contact time and reaction rate between ozone and water
impurities. High dose of ozone, homogeneous mixing, long contact
time and fast reaction rate between ozone and water impurities are
essential to achieve high disinfection efficiency.
[0010] U.S. Pat. No. 5,427,693 discloses an apparatus used for
treating contaminated water. A 50 to 200 feet length of tubing is
used to enhance the contact time. Obviously, using such a long
tubing is not practical in household drinking water purification
because of space limitations. U.S. Pat. No. 5,250,177 also uses a
long tubing to enhance the contact time. However, use of tubing
only will not achieve high disinfection unless very long tubing is
used. U.S. Pat. No. 5,851,407 discloses an apparatus using ozone
and hydrogen peroxide for water decontamination. One type of static
mixer is disclosed. While the effectiveness of disinfection is
allegedly enhanced, the contact time is not enough for drinking
water purification. U.S. Pat. No. 5,766,488 discloses an apparatus
in which the ozonizer serves as a static mixer. This apparatus is
believed too complicated and costly to be used in households. U.S.
Pat. No. 5,888,403 utilizes a complicated static mixer for ozone
and water mixing. Each of the patents referenced above only
emphasizes one of the factors which affect disinfection
effectiveness. However, all the factors have to be optimized in
order to achieve high disinfection.
[0011] The known prior art fails to teach or even suggest the
combinations of structural elements and method steps disclosed and
claimed herein which cooperate to provide a highly efficient,
inexpensive approach for ozone treatment of water which is
practical and suitable for household as well as other uses.
SUMMARY OF THE INVENTION
[0012] It is an object of the invention to provide a system
including a compact apparatus that produces superior disinfection
and oxidation of organics and inorganics in water and which is
suitable for household and other uses.
[0013] The water purifier apparatus of the present invention
includes an ozone generator and a source of water.
[0014] Fluid combining means is incorporated in the apparatus for
receiving ozone from the ozone generator, for receiving water from
the source of water and for introducing the ozone into the
water.
[0015] Fluid mixer means is provided for mixing the water and ozone
received by the fluid combining means to provide a substantially
homogeneous mixture of water and ozone.
[0016] The apparatus also includes fluid flow path defining means
forming a confined flow path for receiving the substantially
homogeneous mixture of water and ozone from the fluid mixer means.
The confined flow path has a length sufficient to provide
substantially complete decomposition of the ozone in the
homogeneous mixture of ozone and water passing therethrough. The
fluid flow path defining means has an exit for water in the
confined flow path after substantially complete decomposition of
the ozone in the substantially homogeneous mixture of ozone and
water has occurred.
[0017] The fluid mixer means comprises an inline static mixer
providing substantially complete transverse mixture uniformity with
minimal longitudinal mixing of the combined water and ozone passing
through the fluid mixer means.
[0018] The water purifier apparatus also includes a catalyst holder
having an inlet and an outlet and defining a holder interior
accommodating at least one catalyst. The catalyst holder is located
downstream from the fluid mixer means and receives and treats the
substantially homogeneous mixture of water and ozone from the fluid
mixer means.
[0019] The invention also encompasses a method. According to the
method, ozone is generated and introduced into water. After this
step, the water and ozone are mixed to provide a substantially
homogeneous mixture of water and ozone.
[0020] The substantially homogeneous mixture of water and ozone is
introduced into a confined flow path.
[0021] The substantially homogeneous mixture of water and ozone
flows through the confined flow path for a period of time
sufficient to provide substantially complete decomposition of the
ozone in the substantially homogeneous mixture of ozone and water
so that no offgas ozone destruction is required after the water
from the substantially homogeneous mixture of ozone and water exits
the confined flow path.
[0022] Other features, advantages and objects of the present
invention will become apparent with reference to the following
description and accompanying drawings.
DESCRIPTION OF DRAWINGS
[0023] FIG. 1 is a cross-sectional, elevational view of the ozone
generator of the apparatus;
[0024] FIG. 2 is a schematic view of a preferred embodiment of the
water purifier apparatus;
[0025] FIG. 3 is a perspective view of a mixing element of an
inline static mixer employed in the apparatus; and
[0026] FIG. 4 is a cross-sectional, elevational view of a component
of the invention defining a fluid flow path and including a filter
for receiving water from the flow path.
BEST MODE FOR CARRYING OUT THE INVENTION
[0027] Referring now to the drawings, apparatus of the present
invention incorporates an ozone generator 10. As shown in FIG. 1,
the ozone generator 10 includes a tube 12, preferably formed of
glass. An inner cylindrically-shaped electrode 14 constructed of
stainless steel is in contact with the inner wall of tube 12. An
aluminum oxide jacket 16 is maintained in contact with the inner
wall of electrode 14. As will be described in greater detail below,
cooling water passes through a passageway 18 defined by jacket 16
for cooling the inner electrode 14. Conduits 20, 22 are formed at
the ends of jacket 16 to provide fluid flow communication with the
passageway 18.
[0028] The ozone generator 10 also includes an outer
cylindrically-shaped electrode 26, suitably formed of stainless
steel. The outer electrode 26 is grounded and an annular space 28
is formed between glass tube 12 and electrode 26.
[0029] Oxygen-containing gas is fed into annular space 28 through
gas inlet 30 and ozonized gas exits the ozone generator through
outlet 32. End caps 34 maintain the above-described components of
the ozone generator properly fixedly positioned relative to one
another.
[0030] When a high voltage is applied across the inner and outer
electrodes, silent discharge occurs therebetween so as to produce
ozone in the oxygen-containing gas in space 28.
[0031] The ozone generator is associated with a power supply unit
36 which may, for example, have a 30 W and 15 KV capacity. Glass
tube 12 may suitably have a 22 mm diameter and thickness of 1 mm to
act as a dielectric medium. The outer electrode 26 suitably may
have a 25 mm inner diameter, carrier air or gas passing through the
discharge space between the two electrodes being exposed to a fixed
voltage of 15 KV.
[0032] The apparatus can inexpensively and readily treat water such
as tap water flowing from a source of water indicated by water
valve 40 in the arrangement depicted in FIG. 2. Water from source
40 passes through and is purified by an activated carbon filter 42.
After passing through the filter 42, the water flows through a
water sensor 44 of any suitable construction and type which is
employed to sense the presence of water at that location. Once the
presence of water is sensed by water sensor 44 a signal will be
sent from the sensor to power supply 36 which in turn energizes
ozone generator 10. Also activated is an air compressor 46 which
serves to direct oxygen-containing gas to the inlet of ozone
generator 10.
[0033] Ozonated gas from the ozone generator 10 flows to a
container 50 of the apparatus which receives water from water
sensor 44. Generated ozone is pumped into the water by the air
compressor 46 through a stone 52 of high porosity, creating very
small bubbles which rise slowly through the water in the interior
of container 50. The slower the rate of bubble rise through the
water, the greater the amount of ozone transferred to the
water.
[0034] The water and ozone flow from container or vessel 50 into a
fluid mixer in the form of inline static mixer 56 which includes a
pipe housing one or more inline static mixer elements of the type
shown in FIG. 3. The static mixer element is identified by
reference numeral 60 and a plurality thereof are shown
diagrammatically in FIG. 2. The static mixer elements employed
provide complete transverse uniformity and minimize longitudinal
mixing; therefore, their performance approaches perfect plug flow
conditions. Static mixer elements of this type are known and
available commercially. For example, ConProTec Inc. makes available
an MS 13-32 static mixer element suitable for use when practicing
this invention. The mixer elements of the inline static mixer
alternately divide and recombine fluids passing therethrough. As a
result they create shearing action at the cost of pressure drop
which, in the present instance, causes both a mixing of water and
ozone and an increase in water/ozone contact time. By way of
illustration, sixteen mixer elements of the type shown in FIG. 3
have been employed inline to produce the desired results. The mixer
elements can be made by the thermal plastic injection molding
process. The mixing performance is excellent and the cost is
low.
[0035] The ozonated water passes through catalyst material (not
shown) in the interior of a catalyst holder 64 having an inlet and
an outlet. The catalyst holder is located downstream from the fluid
mixer 36 and the catalyst material may, for example, consist of
silver powder or ceramic powder coated with silver, manganese
oxide, etc. Large amounts of bacteria and viruses are absorbed on
the surfaces of the catalysts, killed by ozone and desorbed from
the surfaces of the catalyst material; therefore, new bacteria and
viruses in the water can be continuously absorbed. The contact time
between the ozone and the bacteria and viruses is increased due to
passage through the catalyst holder and the reaction rate between
ozone and impurities such as bacteria and viruses in water is
enhanced by the catalytic process.
[0036] From catalyst holder 64 the conveyed mixture enters a unit
68 that serves the dual purpose of forming a relatively lengthy
confined flow path for the substantially homogeneous mixture and
acting as a filter for the water thereof. The confined flow path
may, for example, have a length in the order of seven meters or so.
By employing this long confined path, the period of contact between
ozone and water can be further increased. For example, depending
upon component sizes, flow rates and other considerations, contact
time can be extended one minute or more.
[0037] It is known that ozone is not a stable molecule. It may be
decomposed by collision induced dissociation; the longer the path
the more likely that the ozone can be consumed by reaction with
impurities in the water and be decomposed. In the present
invention, large amounts of ozone are consumed by operation of the
inline static mixers previously described, only relatively small
amounts of ozone passing through the confined flow path of unit 68
which serves as an additional ozone/water mixer and offgas ozone
destroyer by utilizing the collision induced dissociation process.
This means that no high temperature and relatively expensive offgas
ozone-destroyer mechanism need be employed as is the case in
conventional ozone water purification systems.
[0038] FIG. 4 discloses the components and operation of unit 68.
More particularly, unit 68 is of unitary structure and includes an
outer housing segment 70 and an inner housing segment 72. The inner
housing segment 72 is positioned within the interior of the outer
housing segment. Both housing segments are connected to a base 74
having an inlet 76 and an outlet 78. The base and housing segments
are suitably formed of molded plastic. Unit 68 is in the nature of
a unitary cartridge which may suitably be releasably connected by
means of inlet 76 and outlet 78 to the rest of the apparatus. The
inlet and outlet have annular grooves to accommodate O-rings to
provide a fluid-tight seal at the connection location.
[0039] A helical groove 80 is formed about the outer periphery of
inner housing segment 72. The helical raised portions 82 of the
inner housing segment defining the groove bear against the inner
surface of outer housing segment 70.
[0040] The water/ozone mixture from catalyst holder 64 enters inlet
76 as shown by the dash lines with arrows in FIG. 4 and enters the
confines of the helical groove. The mixture moves around the inner
housing segment within this enclosed, lengthy passageway until it
exits at the upper end of the inner housing segment. Flow then
moves downwardly within an activated charcoal filter 84 positioned
within chamber 86 of inner housing segment 72. The filtered water
exits the unit 68 through outlet 78.
[0041] The water exiting the filter 84 is virtually free of ozone
and no offgas ozone destroyer need be employed with the
apparatus.
[0042] From unit 68 the treated water proceeds to a flow meter 90
which is used to monitor the quality of purified water and remind
the user when one or more of the activated carbon filters should be
changed. With respect to filter 84, this is readily accomplished by
providing screw threads or some other means to allow removal of the
outer housing segment from base 74 so that access is had to the
chamber 86 holding the filter.
[0043] After passing through flow meter 90 the water progresses to
ozone generator 10, flowing through conduit 22 through passageway
18 and then out of the ozone generator through conduit 20 for use
by the consumer. As mentioned above, this water flow helps cool the
ozone generator components.
* * * * *