Note: Descriptions are shown in the official language in which they were submitted.
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TECHNICAL FIELD
The invention relates to a water treatment device that can purify water near
its point of
use. The device uses ultraviolet light emitting diodes as its primary source
of purifying radiation.
The device uses several novel improvements to increase efficiency, reduce
size, and enable it to
be easily configured depending on the desired usage. The device may be
positioned so that it
treats water near its point of use, such as a faucet, refrigerator, pool or
any other application
requiring purified water.
BACKGROUND OF THE INVENTION
Disinfection of water using ultraviolet light based purifiers is currently
used in many
markets such as, disinfection of potable water for cities and residential use,
beverage makers,
water for pools and hot tubs, or water supplied to transport vehicles, boats
and aircraft.
Current UV systems use large mercury UV lamps as their primary source of UV
radiation. These
systems have a number of drawbacks that the present invention means to
improve. Lamp
based systems typically consist of a treatment chamber into which a single or
multiple
ultraviolet lamps are positioned. The contaminated water flows around the
lamps where it is
exposed to UV radiation and then discharged. The efficiency of these types of
systems depends
on ensuring that the correct dosage of UV radiation is passed through the
volume of water
evenly. Due to uneven water flow in the treatment chamber the effective UV
dosage may be
reduced. Some lamp based designs attempt to correct this by using baffles to
mix the water
and to ensure even exposure to UV radiation as in Canada Pat. No. CA2132930
entitled "Water
Sterilizer With Turbulence Generator".
In addition, most common lamp based designs, consisting of a long UV lamp
housed
inside a cylindrical treatment chamber, have reduced UV dosage as a
significant amount of UV
radiation is absorbed and scattered by the treatment chamber walls. To counter
this, some
systems use special coatings on the treatment chamber walls to reduce UV
absorption. This
coating adds to the overall system cost and manufacturing complexity.
The UV lamps employed in these systems present further problems to systems
design.
The lamps require a "warm up" period before full UV output is reached. As this
time delay could
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cause untreated water to pass through the system, lamp based UV reactors are
often left on
continuously, regardless if water is flowing or not. This always-on
characteristic wastes power
and shortens the usable lifespan of the lamp. Since the lamp's life span is
limited, these lamps
must be replaced, usually every year or less. In systems employing large
arrays of UV lamps to
treat large flowrates of water, the constant cost of lamp replacement is a
significant source of
maintenance expense.
Since UV light emitting diodes can be turned on and off instantly, with almost
no delay
to reach full output, the system can be turned off when no water is flowing.
This significantly
increases the life of the UV light emitting diodes and reduces energy waste.
As current UV light
emitting diodes have much lower power output than UV lamps, improvements made
to the
efficiency of the sterilizer significantly improves the system performance.
The object of the present invention is to provide a water purifier device
which
uses UV light emitting diodes and employs a number of different methods to
improve the
overall system efficiency by increasing the UV radiation delivered to the
treated water.
SUMMARY OF THE INVENTION
The present invention described herein relates to a water treatment device
that uses UV
LEDs to purify water. The device may be located at or near its point of use
such a faucet,
refrigerator, pool, or mounted on vehicles such as boats, aircraft and RVs.
The device may have
a single or multiple UV LEDs depending on flow and treatment requirements. The
device is
designed in such a way that the same general layout can be used for different
configurations
either by scaling the system Up or by connecting multiple devices together.
In the present embodiment, the treatment device consists of: an inlet manifold
and
outlet manifold, a single or multiple UV LEDs, lenses to collimate and focus
the UV radiation
parallel to the treatment chamber, lens blocks and lens retainers to hold the
lenses in correct
alignment, a treatment chamber to direct the water flow, UV transparent
windows to allow the
UV radiation to pass into the flow of water, printed circuits boards which
drive the UV LEDs and
may contain other electrical components which can be used to detect when water
is flowing
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though the device or monitor the operating characteristics of the device. The
inlet and outlet
manifolds may direct the water in such a way as to induce a circulating flow
pattern in the
water to improve mixing characteristics.
By using UV LEDs, combined with the precise focusing lenses, good fluid mixing
characteristics, and relatively simple and modular design, the present
invention represents a
substantial advancement over other UV water treatment designs. The present
device gives
advantages of: Compact size, efficient operation, ease of installation,
modular design, and
relatively low cost. By focusing the UV radiation parallel to the inside of
the treatment
chamber, a desirable uniform dose of UV radiation can be achieved. By using
sensors or
switches to measure water flow, and given the fast activation of the UV LEDs,
the device can be
cycled on only when water is'flowing through the system, reducing electrical
consumption and
increasing the service life of the LEDs.
DETAILED DESCRIPTION
Referring to Figure 1, the general layout of the device with UV LEDs at each
end can be
seen. Contaminated water enters the device as indicated by arrows though an
adapter fitting
15 and passes into the manifold block 1. The device may receive water from a
pressurized
household water line, gravity feed tank, small pressure tank or other water
source. As shown
on Figure 3, the inlet to the manifold block la, may be offset from center to
induce a circulating
mixing flow in the water. The manifold block 1, contains attachment features
to connect the
treatment chamber 3 and lens block 2. The printed circuit board 7, is mounted
to the back of
the lens block using any number of attachment features, in the present
embodiment, 4
threaded screws 6 are used. In the current embodiment, the threaded screws
pass through
holes in the lens block and Rate with threaded holes in the manifold block,
permitting easy
disassembly of the device.
As shown in Figure 3, the printed circuit board 7 supports one or more UV LEDs
7a,
which are positioned such that the UV radiation is focused and passed into the
treatment
chamber. The LEDs may be secured to the printed circuit board in any
appropriate means, in
the current embodiment, the LEDs are surface mount soldered onto the printed
circuit board.
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To ensure proper optical alignment with the lenses 8-9, the printed circuit
board may have
alignment features such as pins or notches. In the present embodiment,
alignment pins 14 are
used, these pins insert into the printed circuit board and mate with holes in
the lens block. The
UV LEDs 7a emit ultraviolet radiation in a wave length that disrupts the DNA
of bacteria,
viruses, and mold spores, rendering them inert and harmless. Thermal paste may
be applied
between the printed circuit board and the lens block to help cool the UV LEDs,
if required a
small heat sink may be attached to the back of the printed circuit board
depending on load and
operating temperature. The wave length of UV radiation may be between 180-
400nm, in the
current embodiment the UV LEDs have a peak wavelength between 250-280nm.
The UV LEDs 7a, and lenses 8,9 are positioned such that the rays of UV
radiation are
collimated, focused, and passed into the flow of water. The UV radiation
passes into any
bacteria or viruses in the wafer and alters their DNA/RNA. The bacteria and
viruses are thus
rendered inert by either killing them outright or altering the reproductive
mechanism in their
DNA/RNA so they can no longer reproduce.
As shown in Figure 3, a configuration of lenses 8,9 is used to collimate and
focus the UV
radiation into the treatment chamber. The current embodiment uses two lenses
but any
arrangement of lenses may be used, for example an aspherical lens, with curved
surfaces on
both sides, may perform the role of the current two lens arrangement. The
first lens, 8 collects
the majority of the UV radiation emitted by the LED 7a, and focuses it evenly
on the second lens
9. The second lens 9 collimates the UV radiation generally parallel to the
treatment chamber 3,
this reduces losses from reflection off the walls of the treatment chamber and
maximizes the
UV energy delivered to the contaminated water. The UV transparent window 4
allows the UV
rays to enter the treatment chamber while providing a barrier to the water
flow. The UV
transparent window and lenses may be made of any UV transparent material, in
the present
embodiment, they are constructed of quartz glass. Several sealing elements 5
and 12, provide a
waterproof seal against the manifold block and the window. The window may be
mounted into
grooves cut into the manifold block lb, which also has grooves for the sealing
elements 5 and
12.
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=
The lens block holds the lenses in correct position using any appropriate
means of
alignment. In the current embodiment, accurate grooves applicable for the
chosen lenses are
used. In the current embodiment two grooves 2a and 2b position the lenses. A
lens retainer
plate 10 and retainer screws 11 may be used to retain one or both lenses. In
the current
embodiment, the first lens 8 is held in place by the lens retainer and screws
while the second
lens 9 is retained by close tolerance with the window 4 and adhesives. The
lens block also
provides for accurate mounting of the printed circuit board 7 and UV LED 7a.
The treatment chamber 3 is mounted between the two manifold blocks 1. The
treatment chamber may be joined to the manifold block using machined threads,
adhesives,
press fittings, welding or any appropriate attachment method. In the current
embodiment,
silver solder is used to join the treatment chamber to the manifold blocks as
silver is non-toxic
and provides a long lasting, leakproof joint. The treatment chamber may be any
size or shape
required by the design, it may be square shaped or circular.
The treatment device, by using a switch or water flow sensor, may run on
demand or
continuously depending on requirements. Using the device on demand will
greatly reduce
power requirements.
As shown in Figure 1 and Figure 2, the device has UV LEDs mounted at both
ends, the
device can be easily configured to have only one LED as show in Figure 4 by
removing one lens
block and lens assembly and replacing them with a modified manifold block 16.
As show in
Figure 5, multiple devices may be connected together, thus increasing the
treatment capacity
and flow rate. In the present embodiment, one UV LED is used per set of
lenses, it can be
understood that multiple LEDs may be placed behind a set of lenses to increase
the UV power
delivered to the water. If multiple LEDs are used they may be positioned on
the printed circuit
board in any desired orientation such as a circular or square pattern so that
the light is focused
by the lenses.
