Note: Descriptions are shown in the official language in which they were submitted.
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Description
PCT Patent Application
Title: An ~~p~over~ Self-C~eantng 111~ater P~oEesstng Apparatus
Cross Reference to Related Applications
This Application claims the benefit of the filing of t~S Provisional Patent
Application Ser. No 60/526,580, entitled "An Improved Self cleaning Water
Processing Apparatus," filed on December 2, 2003, and the specification
thereof
is incorporated herein by reference.
Background of the Invention
Field of Invention:
This invention pertains to the distillation of water and other liquids and,
more
specifically, to a distillation system arid method utilizing initial degassing
of the
liquid, evaporation by boiling, selective separation of steam and vapor, and
product condensation.
Relevance of the Invention:
Water purification technology is rapidly becoming an essential aspect of
modern
life as conventional water resources become increasingly scarce; as municipal
distribution systems for potable water deteriorate with ages as increased
water
usage depletes wells and reservoirs, causing saline water contamination; and
as
further cor~tarnir~ation occurs in conventional resources frram intensive
agriculture,
from gasoline additives, and even from heavy toxic metals, leading to
increasing
and objectionable levels of germs and bacteria, salts, MTBE, chlorates and
perchlorates, arsenic, mercury, and chemicals used to disinfect potable water,
such as chlorinated compounds.
Conventional technologies, such as reverse osmosis (RO), filtration, and
chemical treatment rarely are able to handle the diverse range of water
contaminants, and even though they are commercially available, they often
reduire multiple treatment stages or combination of various technologies to
achieve acceptable water quality. Less conventional technologies, such as
ultraviolet (UV) light irradiation or ozone treatment can be effective against
viruses and bacteria, but seldom remove other contaminants, such as dissolved
gases, many salts, hydrocarbons, and insoluble solids. And most distillation
technologies, which are generally superior at removing multiple contaminants,
and unless they include selective steam separation systems, are still unable
to
handle all types of contaminants.
Accordingly, sophisticated distillation systems that are continuous, self
cleaning,
and recover a major fraction of the input water appear as the best long-term
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option to resolve increasing water contamination problems and water scarcity.
However, to be effective, such distillation systems must remove solids,
dissolved
gases, dissolved salts, bacteria and viruses, as well as odors and
hydrocarbons,
which is the subject of this invention.
References Cited
U.S. Patent Documents
Patent Date Inventors Ass~nee
No
6,689,2512110104 William H. Zebuhr Ovation Products
6,423,1877/23/02 William H. Zebuhr Ovation Products
6,663,77012/16/03 Stephan B. Sears
5,968,32110/19/99 Stephan B. Sears Ridgewood Water Pure
6,436,2428/20f02 Sanchez, et at Sanchez and Joaquin
6,506,2841/14/03 Tetsuo Miyasaka Vacuum dist
6,428,6568/6/02 8leth, et al PSI-ETS
6,406,5976/18102 Chi-Hsiang Wang
6,365,0054!2102 ,lames W. Schleiffarth
6,294,0549/25/01 Douglas E. Suffer
6,113,7449/5/00 James Munro
5,729,9873/24/98 Joel V. Miller
5,484,5101/16/96 Hartman, et al Dew Enterprises
5,587,05512/24/96 Hartman, et al
5,536,3757/16/96 Jonathan C. VogelmanEmerson Electric
5,522,9706/4/96 Shimizu, et al Japan Gore-Tex
5,435,8917/25/95 William H. Snitchler
5,232,0858/3/93 Hayashi, et al Hitachi, Ltd.
4,938,868 7!3/90 Thomas R. Nelson
Description of Prior Art
Previous attempts at removing all contaminants from grater distillation
systems
are known from U.S. Patents 6,689,251; 6,423,187; 6,663,770; 5,968,321;
6,506,284: 6,428,656; 6,406,587; 6,294,054; 6,113,7E#.4; 5,729,987; 5,484,510;
5,587,055; 5,536,375; 5,522,970; 5,435,891; 5,232,085; and 4,938,868.
U.S. Patent 6,689,251 describes a distiller with a heat exchanger that allows
for
the periodic bleeding of boiler water as the impurity concentration in that
water
increases. however, there is no provision for separating tl-~e steam produced
in
the boiler into clean and impure fractions. Another patent from the same
inventor,
U.S. Patent 6,423,187 describes a distiller system that operates an the
principle
of thin-film evaporation by means of capillary action wicks.
U.S. Patent 6,663,770 describes a self cleaning distillation system comprising
a
degasser, boiler, and steam separation system. However, that invention
includes
a float valve to control the water level in the boiler, with the attendant
abrasion
and mechanical stability problems associated with such systems at boiling
temperatures. It also describes a shaft that operates a mechanical wiper for
cleaning the boiler, which introduces potential leak and maintenance problems.
U.S. Patent 5,968,321 describes a similar distillation system that relies on a
heat
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exchanger and a compressor to recover part of the heat of condensation, and
controls the level of water in the boiler by means of ar side glass tube
connected
to a photo-sensing device.
In addition, there is a number of U.S. Patents, such as 6,436,242; 6,506,284;
6,294,054; that utilize vacuum distillation as a means of reducing the energy
requirements due to evaporation. While vacuum distillation effectively allows
boiling at less that 100°C, it is prone to leaks, and such leaks become
increasingly likely the larger the distillation unit becomes. Another common
deficiency of vacuum distillation systems is that they usually require a vapor
compression stage, and compressors suffer from high maintenance costs and,
unless they are especially sealed, can introduce lubricant contamination into
the
water product. Thus, vapor compression distillers, such as U.S. Patents
6,365,005; also suffer from similar reliability and contamination problems.
U.S. Patent 6,428,656 describes a screen above the boiling level of the boiler
as
a means of capturing the salt-containing mist droplet. Metallic or hydrophilic
screens can capture liquid droplets, but the efEicieney of capture is a
furtetiorf of
droplet size, and unless the screen apertures are microscopic (which in turn
cause a significant pressure drop across the screen), they can allow passage
of
small mist droplets.
U. S. Patent 6,40fi, 597 describes a distiller with a de~asser and a demister.
The
demister consists of a flexible tube. Collecting impure mist droplets in a
tube is
generally a stochastic process that is seldom '100% efficient, and depending
of
the chemical composition of the polymer tube, impurities can leach into the
steam that eventually becomes product water.
U.S. Patent 6,113,744 describes a degasser where raw water is introduced
between the top and the bottom of a tubular member, with steam exit at the top
of the unit and degassed water at the bottom. Such configuration achieves
degassing only of the most volatile components in the water stream and is less
efficient that the present invention, particularly when volatile components
like
MTBE and ,chlorine are both present in the raw water.
U.S. Patent 5,729,987 describes a distillation apparatus for use with salt
water
and is based on an array of steam separator ducts that prevent mixing of salt
water with desalinized water, and using an ammonia refrigerant for heat
exchange.
U.S. Patents 5,484,510 and 5,587,055 describe a distillation system that
separates clean from impure steam by mearfs of a pump actuated by an electric
conductivity probe. However, conductivity measurements in the gas phase are
effective only if the steam is homogeneous, which is riot the case when mist
containing micro-droplets of liquid are present.
U.S. Patent 5,536,375 describes a vacuum distillation system that utilizes a
mechanical baffle to separate mist droplets from steam. However, in addition
to
the aforementioned problems of vacuum distillation, a~ baffle is only
effective at
capturing droplets above a certain size; smaller droplets have significantly
lower
inertia and will continue to be entrained by the flow of steam.
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U.S. Patent 5,522,970 describes a distillation system based on a
polytetrafluoroethylene tube that is permeable to water steam but imp~ermeab(e
to
saline water.
U.S. Paterft 5,435,89'! describes a distillation system that elimirfates gases
l~~
heating, but there is no provision for separating clean from impure steam.
U.S. Patent 5,232,085 describes a distiltation system that inetrxdes a
degass~er, a
high-pressure boiling chamber, and a hydrophobic membrane to separate the
steam from mist droplets. However, in addition to the aforementioned proble-
ins
regarding high-pressure systems, a membrane separator is effective only if the
mist droplets are within a certain size; smaller droplets carp be carried
throuc,~h by
the steam flow because of their low inertia.
U.S. Patent 4,938,868 describes a vacuum distillation system that utilizes a
circular mist collector to separate mist droplets from clean steam. However,
in
addition to the aforementioned problems associated with vacuum distillation,
the
patent recognizes that only large mist particles can be collected.
The objective of the present invention is to provide a continuous, fully
automated
water distillation system that removes gases, solids, salts, hydrocarbons, and
micro-organisms from water.
Summary of the Invention
An imprcwed, self-cleaning water processing apparatus comprises three
sequential functions that eliminate multiple contaminants from drinking water_
First, dissolved gases, such as odors and most hydrocarbons, are eliminated by
means of a degasser. Next, a special design boiler produces steam that may
carry micro-partictes of sotids or sate containing mist. The mixt~xre of clean
ar~~t
contaminated steam is then separated into pure and impure steam by means of a
cyclone demister. The clearf steam fraction is finally collected in a
cflndenser'
which feeds a pure water product tank.
Brief Description of the Drawings
FIGURE 'I is top view of the boiler chamber 2, the degasser unit 4, and the
cyclone demister 3.
FIGURE 2 is a side view of the distillation core, showing the degasser 4, the
boiler chamber 2, and the cyclone demister 3.
FIGURE 3 is a detailed view of the cyclone demister 3, illustrating a
preferred
configuration of various elements, such as an incoming steam tube 11, a
metallic
steam guide 10 that directs the steam to rotate in a circular pattern, a mist
collector tube 6 that directs impure steam and mist into a waste drain, and a
clean steam collector tube 5 that carries the clean steam into a condenser un
it.
FIGURE 4 is a detailed drawing of the degasser unit 4 as mounted above the
boiler chamber 2 orf the boiler top ~. It illustrates a preferred
configuration for the
incoming feed water tube 12, the position of a coifed heat exchanger 8 inside
the
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boiler chamber 2, the hot water tube 13 that feeds the top of the degasser
unit 4,
the mixing media 14 inside the degasser unit 4, the screen 15 that supports
the
mixing media 14, and tube 16 that carries contaminated steam and mist to a
waste drain.
Detailed Description
As illustrated in the drawings, the distillation system comprises a boiler, a
degassing unit, a demister far steam separation and a product condenser. FI~.
'I
and FIG. 2 are top and side views of the apparatus constructed in accordance
with the invention. The boiler top (1} is the primary structural element of
the
apparatus and mounted to it are the boiling chamber (2), the cyclone demister
(3), and the degasses (4). O-rings (not shown) form the seat between the
boitirrg
chamber and boiler top; and between the cyclone demister and boiler top. All
materials in the apparatus are selected to minimize corrosion of the apparatus
or
contamination of water being processed, such as titanium or stainless steel.
- Design has been improved to enable high-volume component fabrication and
high-volume manufacturing assembly processes, substantially reducing
manufacturing costs. Steel drawing of the boiling chamber eliminates gaskets
or
seals in the boiler, thereby minimizing maintenance costs, while making the
body
of the boiler easier and more economical to manufacture. In addition, making
the
body of the boiler by steel drawing and forming makes the unit more durable,
thus extending the useful life of the core assembly.
- Design has been improved to enable speedy disassembly for the purposes of
inspection, service cleaning, and repair or replacement of components. The
boiler chamber 2 is attached to the boiler top 1 by a series of peripheral
bolts and
an C-ring that is placed outside the line c~f bolts, sa as effect a
compression seal,
thus minimizing any contact between the steam and the Q-ring.
- Design has been improved to withstand the mechanical shock and vibration
performance seen in transportation, installation, and continuous operation.
The
ability to withstand these stresses significantly improves the reliability of
the
apparatus.
Cyclone Demister Component:
- The design of the cyclone demister 3 improves prior art by combining and
integrating the cyclone chamber, steam nozzle, and demister seal gland into a
single component which may be fabricated by molding, casting, or stamping a
variety of corrosion resistant materials. In a preferred embodiment, the body
of
the cyclone demister is made from either titanium or stainless steel, although
other temperature and corrosion resistant materials may also be used.
- The attachment of the demister 3 to the boiler top 1 is accomplished by
threaded fasteners and by a compression seal made with an o-ring.
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- As shown in Figure 3, the cyclone demister is basically a modified cyclone.
Steam from the bailer chamber enters the cyclone demister through tube 11.
Upon entering the cyclone chamber, steam from the boiler encounters a metal
guide 10 that forces the steam into a circular motion. The circular motion of
steam in the cyclone causes mist particles, which are heavier than dry or
clean
steam to concentrate on the periphery of the cyclone chamber due to
centrifugal
forces, while clean steam, being lighter, follows a circular motion closer to
the
center of the cyclone chamber. As should be apparent to those versed in the
art,
the cyclone demister has no moving parts, and effects a selective separation
of
clean steam from impure mist particles purely as a result of differential
centrifugal
forces. During this circular motion, the concentrated mist stream, also called
"blow-down," encounters exit tube 6 and leaves the cyclone demister as waste
steam. This waste steam subsequently joins the gray water stream and goes to a
drain. Dry or clean steam exits from the center top of the cyclone demister
through tube 5 and goes to a condenser unit.
Boiling Chamber Component:
The boiling chamber 2 design makes improvement over prior art by employir:g
high volume metal forming technology to minimize the number of seams, seals,
and piece parts wk~ich sigrfificarftly improves manufacturing cost and
reliability of
the device.
- The single and only boiling chamber seal, except for drains, is made above
the
operating water line which further reduces the opportunity for leakage during
normal operation.
- The heating element 10 which is permanently and intimately attached provides
heat in a confined area of the boiling chamber bottom. The nature of boiling
water causes (sediment) or scale to form on or near surfaces where the boiling
process takes place. Glass or ceramic balls 7 within the boiler are agitated
by
the boiling water and prevent the scale from being deposited on the surface of
the boiling chamber keeping the particles suspended in the water during normal
operation.
- At the end of an operational cycle of fihe unit, a sediment drain 9 opens
automatically purging the boiling chamber of nearly all the water and
suspended
scale. This process significantly reduces the long-term build up of scale
which
improves the heating efficiency of the boiler and reci~tces the need for
boiler
cleaning.
- The water level and the steam pressure in the boiling chamber are
automatically regulated by means of a differential pressure switch that turns
the
inlet water valve off when the level of water in the boiler is full.
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- As shown in Figure 4, incoming feed water enters the boiler chamber through
tube 12 and is preheated inside the boiling chamber within a heat exchanger 8
which is suspended from the boiler top 1. The feed water reaches temperature
equilibrium with the boiling chamber and exits through tube 13, which carries
the
hot water into the top of the degasser 4. This preheating process is key to
bring
feed water temperatures near the boiling point before it enters the degasser.
As
is known to those familiar with the art, volatile gases and organic compounds
with a low vapor pressure lose the ability to remain iry solution at
temperatures
dose to the boning point of water, acrd evolve as gases.
Degasser Component:
The Degasser 4 consists of a vertical tube with preheated water erfterirsg the
top
through tube 13 and steam from the boiler chamber 2 entering the bottom and
exiting at the tap through tube 16. The vertical degasser tube 4 can ccantain
a
variety of materials 14 which cause a mixing of the water and steam stripping
off
unwanted gases in the water as it moves slowly down the degasser by
gravitational force. The materials that can be used for this mixing include
glass
balls, ceramic balls, screen discs, spiral screen, or metal chords. A metal
screen
15 that is resistant to corrosion is placed between the degasser tube 4 and
the
boiler top 1, and prevents the mixing media 14, which in a preferred
embodiment
consist of glass spheres, from falling into the boiling chamber.
An important aspect of the present invention concerns the size of the glass
spheres, which must have sufficient surface area to provide for effective
stripping
of volatile components in the short time it takes for the incoming feed water
to
traverse the length of the degasser tube. Horizontal configurations of
degassers
in the prior art normally are not effective for this reason and are, thus,
unable to
completely strip volatile substances from contaminated water. llltrasor~ic
atomization of water may also be used to enhance the steam and water mixing.
