Note: Descriptions are shown in the official language in which they were submitted.
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WO 00178678 YcTn.ts00116346
FLUID TREATMENT SYSTEM
Field of the Invention
The present invention generally relates to a water treatment system and, more
15 particularly, to an inductively coupled ballast for non-contact power
transfer to an
ultraviolet lamp in the water treatment system.
Background of the Invention
The present invention addresses several problems associated with previous
20 point-of-use home or office water treatment systems. A first problem is
that
conventional water treatment systems, utilizing lamp assemblies with
ultraviolet
lamps therein, are energy-inefficient. The lamp assemblies are generally left
continuously running to prevent microorganisms from reproducing within the
water
treatment system as a result of the ultraviolet lamp not being turned on. When
a
25 conventional lamp assembly is turned on, it takes a significant amount of
start-up time
before gas within the ultraviolet lamp is sufficiently excited to output light
of a
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predetermined intensity level required to insure adequate destruction of
microorganisms within the water treatment system. Water which is discharged
from
the water treatment system before an ultraviolet lamp is sufficiently excited
may carry
an unacceptably high level of live microorganisms. A continuously running lamp
assembly uses a significant amount of energy and is, therefore, inefficient.
Also, with
the lamp assembly left running continuously, such as overnight, water residing
within
a water treatment system unit can become uncomfortably warm.
A second problem is with the design of reflector assemblies within water
treatment systems. In an attempt to increase lamp efficiency, reflector
assemblies
may be placed about ultraviolet lamps and water-carrying conduits in which the
microorganisms are irradiated. Light incident from the ultraviolet lamps which
misses striking the water-carrying conduits is reflected back from the
reflector walls
and have a chance to again impinge upon the water-carrying conduits. Often
these
reflector assemblies are circular in cross-section. Unfortunately, a lot of
the
ultraviolet light produced never reaches the water-carrying conduits. Rather,
a
significant portion of light is reabsorbed by the ultraviolet lamp assembly.
A third problem involves the electrical coupling of the lamp assemblies to the
water treatment systems. Every time a lamp assembly is installed in or removed
from
a water treatment system, the lamp assembly must be mechanically and
electrically
coupled and uncoupled relative to the water treatment system. This often
requires
complicated and expensive mounting assemblies. Further, care must be taken to
insure that the electrical connections are not exposed to moisture while
electrical
power is passing through the water treatment system.
Coaxially aligned lamp assemblies and filter assemblies are sometimes used to
minimize the size of water treatment systems. A lamp assembly and filter
assembly
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in a particular water treatment system may or may not be simultaneously
removed
from the water treatment system. If these assemblies are simultaneously
removed,
they are often very heavy as they may be filled with water and have
substantial weight
on their own. Alternatively, even if the lamp assembly and filter assembly are
separably removable from a water treatment system, quite often problems of
water
spilling from one of these assemblies during handling.
Another problem faced by water treatment system units having lamp
assemblies is that complicated monitoring systems are needed to monitor the
lamp
assemblies. As a lamp assembly ages, the intensity of light output from the
lamp
1o assembly generally diminishes. Eventually, the intensity falls below a
level necessary
to effect a desired microorganism-kill rate. The lamp assembly should be
removed
before the critical minimum intensity is reached. Accordingly, a monitor
system is
required to check on the light intensity within the water treatment system.
These
monitoring systems are typically expensive. They often require costly
ultraviolet
sensors with quartz windows.
Conventional ballast control circuits employ bipolar transistors and
saturating
transformers to drive the lamps. The ballast control circuits oscillate at
frequencies
related to the magnetic properties of the materials and winding arrangements
of these
transformers. Circuits with saturating transformer oscillators produce an
output in the
category of a square wave, require the transistors of the half bridge to hard-
switch
under load and require a separate inductor to limit the current through the
discharge
lamp.
These and other deficiencies in prior water treatment system units employing
lamp assemblies and filter assemblies are addressed by the present invention.
01-OE 2001 = US 0000163-,,
3A
Prior ballast circuit designs and water treatment systems that do not use
inductively coupled ballast circuits are taught by U.S. Patent Numbers
4,752,401;
5,230,792; 5,324,423; 5,404,082 and 5,853,572. Prior apparatus and systems
employing radio frequency identification systems for exchangeable parts are
taught by
U.S. Patent Number 5,892,458 and EP-A-0 825,577.
CA 02375336 2001-12-10 AMENDED SHEET
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WO oo/78678 4 PCT/USOO/16346
Summary of the Invention
The present invention discloses an electronic control system for a water
treatment system that includes an inductively coupled ballast circuit. The
water
treatment system filters water by, amongst other things, directing a flow of
water from
a water supply to a filter assembly. The filter assembly removes unwanted
particulates from the flow of water. After passing through the filter
assembly, the
water is directed to a replaceable ultraviolet lamp assembly. The ultraviolet
lamp
assembly destroys organic matter in the supply of water by exposing the water
to
high-intensity ultraviolet light as the water flows through the ultraviolet
lamp
assembly. The ultraviolet lamp assembly provides virtually instantaneous high-
intensity ultraviolet light at the beginning of operation, which provides
advantages
over prior art water treatment systems that require warm-up time. After
exiting the
ultraviolet lamp assembly, the flow of water is directed out of the water
treatment
system through an outlet assembly.
The overall operation of the water treatment system is controlled by a control
unit that is electrically connected with the ultraviolet lamp assembly and the
filter
assembly. In the preferred embodiment, the control unit is also electrically
connected
with a flow sensor, an ambient temperature sensor circuit, an ambient light
sensor
circuit, an ultraviolet light sensor circuit, a power detection circuit, a
display, an audio
generation circuit, a memory storage device, a communications port and a radio
frequency identification system. These devices are all monitored or controlled
by the
control unit and provide various benefits to the water treatment system, as
will be
generally set forth below.
The flow sensor circuit is used by the control unit to determine when water is
flowing, so that the ultraviolet lamp assembly can be energized, and to keep
track of
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the volume of water that is being processed by the water treatment system. The
ambient temperature sensor circuit measures the ambient temperature of the
atmosphere, so that the water treatment system can maintain a temperature
level
above freezing or some other predetermined temperature. The ultraviolet light
sensor
circuit provides the control unit with electrical signals corresponding to the
intensity
of the ultraviolet light that is being emitted by the ultraviolet lamp
assembly. This is
important because these measurements allow the control unit to make
adjustments
that can increase or decrease the intensity of the ultraviolet light being
emitted.
The power detection circuit provides the control unit with electrical signals
1o that indicate the presence or absence of power to the water treatment
system that is
provided from a conventional external power source, such as a wall outlet. The
display is controlled by the control unit and displays information on the
status of the
water treatment system. The audio generation circuit is used by the control
unit to
provide audible sounds in case predetermined system states occur in the water
treatment system that require attention.
The water treatment system further includes a memory storage device that is
electrically connected with the control unit. The memory storage device is
used to
store various data values related to the water treatment system and its
related
components. In the preferred embodiment of the present invention, the memory
storage device is an EEPROM or some other equivalent storage device. A
communications port is connected with the control unit, which provides the
ability for
bi-directional communication between the control unit and a peripheral device,
such
as a personal computer or hand-held monitoring device.
The radio frequency identification system includes an ultraviolet light
transponder that is located in each ultraviolet lamp assembly. In addition,
the radio
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frequency identification system includes a filter transponder that is located
in the filter
assembly. The ultraviolet light transponder and the filter transponder
communicate,
using radio frequency, with the radio frequency identification system. Each
transponder contains certain information that is specific to the ultraviolet
lamp
assembly and the filter assembly. Those skilled in the art would recognize
that
contact-type identification systems may be used instead of the radio frequency
identification system.
The preferred ultraviolet lamp assembly is energized by an inductively
coupled ballast circuit. The preferred inductively coupled ballast circuit is
a self-
oscillating half-bridge switching design that operates at high frequencies
that provide
virtually instantaneous ultraviolet lamp illumination. In addition, the
inductively
coupled ballast circuit self-oscillates once resonance is achieved, uses
MOSFET
transistors as switching elements, and is designed to accommodate an air-core
transformer coupling arrangement, which simplifies the design of an
ultraviolet lamp
assembly. The ultraviolet lamp assembly may be readily replaced, because of
the air-
core transformer coupling arrangement created by the inductively coupled
ballast
circuit.
The preferred inductively coupled ballast circuit includes a control circuit,
an
oscillator, a driver, a half-bridge switching circuit, a series resonant tank
circuit, a
secondary coil, a resonant lamp circuit and a ultraviolet lamp. The oscillator
is
electrically connected with the control unit, which starts the oscillator by
providing
electric signals to the control circuit that energizes the oscillator. During
operation,
the oscillator provides electrical signals to the driver, which then causes
the half-
bridge switching circuit to become energized. The half-bridge switching
circuit
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energizes the series resonant tank circuit that, in turn, inductively
energizes the
ultraviolet lamp in the ultraviolet lamp assembly.
The ultraviolet lamp assembly physically houses the secondary coil, the
resonant lamp circuit and the ultraviolet lamp of the inductively coupled
ballast
circuit. Once the series resonant tank is energized, the secondary coil in the
ultraviolet lamp assembly becomes inductively energized, thereby illuminating
the
ultraviolet lamp. In the preferred embodiment, the resonant frequency for the
inductively coupled ballast circuit is about 100kHz. As such, the secondary
coil in the
ultraviolet lamp assembly resonates at about 100kHz as well. As previously set
forth,
lo the resonant frequency of operation can be adjusted up or down by the
control unit to
accommodate for convenient component selection. In addition, the resonant
frequency is also controlled by the component selection in the series resonant
tank,
which will be set forth in detail below.
As such, a preferred embodiment of the present invention discloses a fluid
treatment system that comprises a control unit; an inductively coupled ballast
circuit
that is inductively coupled with an electromagnetic radiation emitting
assembly,
wherein the inductively coupled ballast circuit inductively energizes an
electromagnetic radiation emitting device in the electromagnetic radiation
emitting
assembly in response to a predetermined electric signal from the control unit.
Another preferred embodiment of the present invention discloses a method of
providing electromagnetic radiation in a fluid treatment system. The method
comprises the steps of generating a predetermined electric signal with a
control unit;
directing the predetermined electric signal to an inductively coupled ballast
circuit;
and inductively energizing an electromagnetic radiation emitting device in the
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8
inductively coupled ballast circuit in response to the predetermined electric
signal from
the control unit.
In another embodiment of the present, a fluid treatment system with a radio
frequency identification system is disclosed. The fluid treatment system
comprises a
control unit; a base station electrically connected to the control unit; and
at least one radio
frequency identification transponder located in a electromagnetic radiation
emitting device
assembly that is in radio communication with the base station. In yet another
preferred
embodiment of the present invention, the electromagnetic radiation emitting
assembly is
replaced with a filter assembly.
Another preferred method disclosed by the present invention relates to a
method
of monitoring electromagnetic radiation emitting assembly information in a
fluid treatment
system. The method comprises the steps of providing an electromagnetic
radiation
emitting assembly for use in the fluid treatment system; generating an
electromagnetic
radiation emitting assembly information signal with an electromagnetic
radiation emitting
identification transponder located in the electromagnetic radiation emitting
assembly;
transmitting the electromagnetic radiation emitting assembly information
signal to a base
station located in the fluid treatment system; and directing said
electromagnetic radiation
emitting assembly information signal to a control unit. In another preferred
embodiment,
the electromagnetic radiation emitting assembly can be replaced with a filter
assembly.
The invention in one aspect provides a method of providing electromagnetic
radiation in a fluid treatment system comprising the steps of generating a
predetermined
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8a
electric signal with a control unit, directing the predetermined electric
signal to an
inductively coupled ballast circuit, and inductively energizing an
electromagnetic radiation
emitting device in the inductively coupled ballast circuit in response to the
predetermined
electric signal from the control unit.
Another aspect of the invention provides a fluid treatment system comprising a
control unit, an inductively coupled ballast circuit that is inductively
coupled with an
electromagnetic radiation emitting assembly, and wherein the inductively
coupled ballast
circuit is adapted to inductively energize an electromagnetic radiation
emitting device in
the electromagnetic radiation emitting assembly in response to a predetermined
electric
signal from the control unit.
Still further the invention comprehends a method of providing electromagnetic
radiation in a fluid treatment system, comprising the steps of generating a
predetermined
signal with a control unit, directing the predetermined signal to a ballast
circuit that
includes an inductive coupler in an outlet cup, positioning an electromagnetic
radiation
emitting assembly in an inductive coupling arrangement with the outlet cup,
wherein the
electromagnetic radiation emitting assembly includes a secondary coil
connected to an
electromagnetic radiation emitting device, and energizing the electromagnetic
radiation
emitting device in response to the predetermined signal from the control unit,
wherein the
secondary coil is inductively energized by the inductive coupler thereby
energizing the
electromagnetic radiation emitting device.
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8b
Another aspect of the invention pertains to a fluid treatment system for
providing
electromagnetic radiation of a fluid, the fluid treatment system comprising a
control unit,
a ballast circuit connected to the control unit, wherein the ballast circuit
includes an
inductive coupler in an outlet cup, an electromagnetic radiation emitting
assembly having
a secondary coil that is connected to an electromagnetic radiation emitting
device, and
wherein the inductive coupler is added to inductively energize the secondary
coil in
response to a predetermined signal from the control unit, thereby energizing
the
electromagnetic radiation emitting device in the electromagnetic radiation
emitting
assembly.
Yet another aspect of the invention provides a method of providing
electromagnetic radiation in a fluid treatment system, comprising providing a
ballast
circuit having an inductive coupler in an outlet cup, placing a replaceable
electromagnetic
radiation emitting assembly including a secondary coil connect to an
electromagnetic
radiation emitting device in an inductively coupled arrangement with the
inductive
coupler, and energizing the inductive coupler thereby inductively energizing
the secondary
coil to illuminate the electromagnetic radiation emitting device.
A fluid treatment system is also disclosed for providing electromagnetic
radiation
of a fluid, the fluid treatment system comprising a ballast circuit having an
inductive
coupler in an outlet cup, and a replaceable electromagnetic radiation emitting
assembly
having a secondary coil connected to an electromagnetic radiation emitting
device,
wherein said inductive coupler is operable to inductively energize the
secondary coil
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8c
thereby energizing the electromagnetic radiation emitting device.
These and other features and advantages of the invention will become apparent
upon consideration of the following detailed description of the presently
preferred
embodiments of the invention, viewed in conjunction with the appended
drawings.
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Detailed Description of the Drawin2s
Fig. 1 is a perspective view of a main housing of the water treatment system
with its top shroud removed and a filter assembly and the ultraviolet lamp
assembly
removed from the base unit.
Figs. 2A-C are exploded perspective views of major components of the water
treatment system.
Fig. 3 depicts a block diagram of the major circuits and assemblies of the
water treatment system.
Fig. 4 depicts a block diagram of the inductively coupled ballast circuit.
Fig. 5 is an electrical circuit schematic of a portion of the inductively
coupled
ballast circuit, the ballast feedback circuit and the interlock circuit.
Fig. 6 depicts the secondary coil, the resonant lamp circuit and the
ultraviolet
lamp of the ultraviolet lamp assembly.
Fig. 7 is an electrical circuit schematic of the starter circuit.
Fig. 8 illustrates an electrical circuit schematic of the radio frequency
identification system used in the water treatment system
Fig. 9 is an electrical circuit schematic of the flow sensor circuit.
Fig. 10 is an electrical circuit schematic of the ambient light sensor
circuit.
Fig. 11 is an electrical circuit schematic of the ultraviolet light sensor
circuit.
Fig. 12 is an electrical circuit schematic of the ambient temperature sensor
circuit.
Fig. 13 is an electrical circuit schematic of the audible generation circuit.
Fig. 14 is an electrical circuit schematic of the communication port.
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Detailed Description of the Presently Preferred Embodiment of the Invention
Referring to Fig. 1, the present invention discloses an electronic control
system for a water treatment system 10 that generally uses carbon-based
filters and
ultraviolet light to purify water. In order to appreciate the present
invention, it is
important to have a general background of the mechanical aspects of the
preferred
water treatment system 10. The preferred water treatment system 10 includes a
main
housing 12, a replaceable ultraviolet lamp assembly 14 and a filter assembly
16. The
ultraviolet lamp assembly 14 and the filter assembly 16 are removable and
replaceable
from the main housing 12. The main housing 12 includes a bottom shroud 18, a
back
shroud 20, a front shroud 22, a top shroud 24 and an inner sleeve shroud 26. A
lens
28 accommodates a display 106 (see Fig. 3) so that information may be
displayed
about the status of the water treatment system 10 through the display 106. To
assemble the water treatment system 10, the ultraviolet lamp assembly 14 is
securely
mounted to the main housing 12 and thereafter the filter assembly 16 is
mounted over
the ultraviolet lamp assembly 14 and to the main housing 12.
As those skilled in the art would recognize, the replaceable ultraviolet lamp
assembly 14 may be made in such a manner that the ultraviolet lamp assembly 14
may not be replaceable. In addition, those skilled in the art would recognize
that the
replaceable ultraviolet lamp assembly 14 may be interchanged with several
different
types of electromagnetic radiation emitting assemblies. As such, the present
invention should not be construed to cover only water treatment systems that
use
ultraviolet lamp assemblies and those skilled in the art should recognize that
the
disclosure of the ultraviolet lamp assembly 14 represents the preferred
embodiment of
the present invention.
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Referring to Figs. 2A-C, the major mechanical components of the water
treatment system 10 are shown in perspective view, as relevant to the present
invention. As illustrated in Fig. 2A, the inner sleeve shroud 26 includes a
plurality of
inner sleeve covers 30, an inlet valve assembly 32 and an outlet cup assembly
34 with
an outlet cup 36. A bottom shroud assembly 38 is further disclosed that
includes the
bottom shroud 18 along with an inlet assembly 40 and an outlet assembly 42. An
electronics assembly 44 fits securely in the bottom shroud 18, the details of
which
will be set forth below in detail. These components are securely mounted to
the
bottom shroud 18, the back shroud 20, the front shroud 22, the top shroud 24,
the
inner sleeve shroud 26 and the lens 28 when the water treatment system 10 is
fully
assembled. A magnet holder 46 and a magnet 48 are also housed in the top
shroud 24
in the preferred embodiment.
Referring to Fig. 2B, the ultraviolet lamp assembly 14 generally includes a
base subassembly 50, a secondary coil 52, a bottom support subassembly 54, a
top
support assembly 56, a pair of quartz sleeves 58, an ultraviolet lamp 60, an 0-
ring 62
and a pair of cooperating enclosure reflector subassemblies 64. Generally
speaking,
the secondary coil 52, the bottom support subassembly 54 and the enclosure
reflector
subassemblies 64 are connected with the base subassembly 50. The enclosure
reflector subassemblies 64 house the pair of quartz tubes 58, the ultraviolet
lamp 60
and the 0-ring 62. The top support assembly 56 fits securely over the top of
the
enclosure reflector assemblies 64 when the ultraviolet lamp assembly 14 is
fully
assembled.
As illustrated in Fig. 2C, the filter assembly 16 generally includes a base
assembly 66, a filter block assembly 68, a filter housing 70 and an
elastomeric filter-
housing grip 72. Generally speaking, the filter block assembly 68 fits over
the base
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assembly 66 which, in turn, is encapsulated by the filter housing 70. The
filter
housing grip 72 fits over the top of the filter housing 70, thereby providing
a better
grip for removing the filter housing 70. The filter assembly 16 filters a flow
of water
by directing the flow through the filter block assembly 68 before being
directed to the
ultraviolet lamp assembly 14.
Referring to Fig. 3, the present invention discloses an electronic control
system 100 for the water treatment system 10 generally described above. In the
preferred embodiment, the water treatment system 10 is controlled by a control
unit
102, which is preferably a microprocessor. As illustrated, the control unit
102 is
electrically connected with the ultraviolet lamp assembly 14 through an
inductively
coupled ballast circuit 103. This control unit 102 is also electrically
connected to the
ultraviolet lamp assembly 14 through two-way wireless communication, as will
be set
forth in greater detail below. During operation, the control unit 102 is
capable of
generating a predetermined electric signal that is directed to the inductively
coupled
ballast circuit, which instantaneously energizes the lamp assembly 14 which,
in turn,
provides high-intensity ultraviolet light that treats the flow of water.
In the preferred embodiment, the control unit 102 is also electrically
connected
with a flow sensor circuit 104, a display 106, an ambient light sensor circuit
108, a
visible light sensor circuit 110, a power detection circuit 112, an ambient
temperature
sensor circuit 114, an audio generation circuit 116, a memory storage device
118, a
communications port 120, a ballast feedback circuit 122 and a radio frequency
identification system 124. As further illustrated in Fig. 3, an ultraviolet
light radio
frequency identification transponder 126 is connected with the ultraviolet
lamp
assembly 14 and a filter radio frequency identification transponder 128 is
connected
with the filter assembly 16. The ultraviolet radio frequency identification
transponder
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126 and the filter radio frequency identification transponder 128 communicate
with
the radio frequency identification system 124 using two-way wireless
communication,
as will be set forth in greater detail below.
Generally speaking, the flow sensor circuit 104 is used by the control unit
102
to determine when water or fluid is flowing and to keep track of the volume of
water
or fluid that is being processed by the water treatment system 10. The display
106 is
driven by the control unit 102 and is used to display information about the
status of
the water treatment system 10. Several different types of displays are known
in the
art and may be used in the present invention; however, the preferred display
is a
vacuum florescent display. The ambient light sensor circuit 108 measures the
amount
of ambient light and, in turn, provides electrical signals to the control unit
102 so that
it can adjust the intensity of the display 106 accordingly.
The visible light sensor circuit 110 provides the control unit 102 with
electrical signals related to the intensity level of the light that is being
emitted by the
ultraviolet lamp assembly 14. This is important because these signals allow
the
control unit 102 to increase or decrease the intensity of the electromagnetic
radiation
being emitted by the ultraviolet lamp assembly 14. Those skilled in the art
would
recognize that the visible light sensor circuit 110 may be interchanged with
various
electromagnetic radiation sensor circuits that are capable of sensing the
intensity of
electromagnetic radiation that is emitted from various electromagnetic
radiation
emitting devices that may be used in the present invention.
The power detection circuit 112 provides the control unit 102 with electrical
signals that indicate the presence or absence of power to the water treatment
system
10. Power is provided to the water treatment system 10 from an external power
source, such as a conventional power outlet. Those skilled in the art would
recognize
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that several circuits exist that monitor external power sources and provide
corresponding electrical signals in response to losses of power.
The ambient temperature sensor circuit 114 measures the ambient temperature
of the atmosphere so that the water treatment system 10 can maintain a
temperature
level above freezing or some other predetermined temperature setting. The
control
unit 102 can energize the ultraviolet lamp 60 to generate heat if necessary.
The audio
generation circuit 116 is used by the control unit 102 to generate audible
enunciations.
The audible enunciations typically occur during predetermined system states
that are
experienced by the water treatment system 10. These predetermined system
states are
recognized by the control unit 102 which, in turn, activates the audio
generation
circuit 116 to create the audible enunciation.
As previously set forth, the memory storage device 118 is also electrically
connected with the control unit 102. The memory storage device 118 is used to
store
various data values related to the water treatment system 10 and its related
components. In the preferred embodiment of the present invention, the memory
storage device 118 is an EEPROM or some other equivalent storage device. Those
skilled in the art would recognize that various memory storage devices are
available
that could be used in the present invention.
The communications port 120 is also electrically connected with the control
unit 102, which provides the water treatment system 10 with the ability to
conduct bi-
directional communication between the control unit 102 and a peripheral
device, such
as a personal computer or hand-held monitoring device. In the preferred
embodiment
of the present invention, the communications port 120 uses the RS-232
communication platform to communicate with the peripheral device. The
communications port 120 may also be connected with the ultraviolet lamp
assembly
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14 and the filter assembly 16 to monitor and control various operational
characteristics of these devices in other preferred embodiments. However, in
the
preferred embodiment of the invention, the radio frequency identification
system 124
is used to report information to the control unit 102 about the ultraviolet
lamp
assembly 14 and the filter assembly 16.
In the preferred embodiment depicted in Fig. 3, the radio frequency
identification system 124 uses signals from the ultraviolet light radio
frequency
identification transponder 126 and the filter radio frequency identification
transponder
128 to report various information to the control unit 102. During operation,
the
ultraviolet light radio frequency identification transponder 126 and the
filter radio
frequency identification transponder 128 communicate with the radio frequency
identification system 124 using wireless communication. Since the ultraviolet
lamp
assembly 14 and the filter assembly 16 are designed to be replaceable at the
end of its
useful life, each ultraviolet lamp assembly 14 and filter assembly 16 contains
a
transponder 126, 128 that stores information specific to each device. Those
skilled in
the art would recognize that the ultraviolet light radio frequency transponder
could be
used in conjunction with other electromagnetic radiation emitting devices or
assemblies. The radio frequency identification system 124 is set forth in
greater detail
below.
Referring to Fig. 4, in the present preferred embodiment of the invention, the
ultraviolet lamp assembly 14 is energized by an inductively coupled ballast
circuit
103 that is electrically connected with the control unit 102. The inductively
coupled
ballast circuit 103 is a self-oscillating, half-bridge switching design that
operates at
high frequencies providing virtually instantaneous ultraviolet lamp
illumination. In
addition, the inductively coupled ballast circuit 103 self-oscillates once
resonance is
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achieved, uses MOSFET transistors as switching elements, and is designed to
accommodate an air-core transformer coupling arrangement, which simplifies the
design of an ultraviolet lamp assembly 14. The ultraviolet lamp assembly 14 or
other
electromagnetic radiation emitting assemblies may be readily replaced because
of the
air-core transformer coupling arrangement created by the inductively coupled
ballast
circuit 103. Those skilled in the art would recognize that inductively coupled
ballast
circuit 103 can be adapted to function as a normal ballast circuit as well.
As illustrated in Fig. 4, the inductively coupled ballast circuit 103 includes
a
control circuit 142, an oscillator 144, a driver 146, a half-bridge switching
circuit 148,
a series resonant tank circuit 150, the secondary coil 52 (see Fig. 2), a
resonant lamp
circuit 152 and the ultraviolet lamp 60. The oscillator 144 is electrically
connected
with the control unit 102, which energizes the oscillator 144 by providing
electric
signals to the control circuit 142. During operation, the oscillator 144
provides
electrical signals to the driver 146, which then causes the half-bridge
switching circuit
148 to become energized. The half-bridge switching circuit 148 energizes the
series
resonant tank circuit 150 that, in turn, inductively energizes the ultraviolet
lamp 60 in
the ultraviolet lamp assembly 14.
As further illustrated in Fig. 4, the ultraviolet lamp assembly 14 houses the
secondary coil 52, the resonant lamp circuit 152 and the ultraviolet lamp 60
while the
electronic assembly 44 (see Fig. 2A) houses the control circuit 142, the
oscillator 144,
the driver 146, the half-bridge switching circuit 148 and the series resonant
tank
circuit 150. As previously set forth, once the series resonant tank circuit
150 is
energized, the secondary coil 52 in the ultraviolet lamp assembly 14 becomes
inductively energized. In the preferred embodiment, the resonant frequency for
the
ballast circuit 103 is about 100kHz. As such, the secondary coil 52 in the
ultraviolet
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lamp assembly 14 resonates at about 100kHz as well. As previously set forth,
the
resonant frequency of operation can be adjusted up or down by the control unit
102 to
accommodate for convenient component selection. In addition, the resonant
frequency may also be controlled by the component selection in the series
resonant
tank circuit 150, which will be set forth in greater detail later.
Referring to Fig. 5, the control circuit 142 is electrically connected with
the
control unit 102 and the oscillator 144. The control circuit 142 includes a
plurality of
resistors 156, 158, 160, 162, 164, 166, a plurality of capacitors 168, 170
172, a diode
174, a first operational amplifier 176 and a second operational amplifier 178.
As
illustrated, resistor 156 is connected with a first direct current ("DC")
power source
180, the output of the control unit 102 and resistor 158. Resistor 158 is
further
connected with diode 174, resistor 160 and capacitor 168. The first DC power
source
180 is connected with capacitor 168, which is also connected with diode 174.
Diode
174 is further connected with a ground connection 182, as those skilled in the
art
would recognize. Resistor 160 is connected with the negative input of
operational
amplifier 176 and the positive input of operational amplifier 178 to complete
the
current path from the control unit 102 to the operational amplifiers 176, 178.
Referring once again to the control circuit 142 depicted in Fig. 5, resistor
162
is connected with a second DC power source 184 and in series with resistors
164 and
166. Resistor 166 is connected with the ground connection 182 and capacitor
170,
which is, in turn, connected with the first DC power source 180 and resistor
164. The
positive input of operational amplifier 176 is electrically connected between
resistors
162 and 164, which provides a DC reference voltage to operational amplifier
176
during operation. The negative input of operational amplifier 178 is
electrically
connected between resistors 164 and 166, which provides a DC reference voltage
to
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operational amplifier 178 during operation. The output of operational
amplifiers 176
and 178 is connected with the oscillator 144, as set forth in detail below.
During operation, the control circuit 142 receives electrical signals from the
control unit 102 and, in turn, acts as a window comparator that only switches
when
the input voltage produced by the control unit 102 is within a certain voltage
window.
The preferred signal from the control unit 102 is an AC signal that, together
with its
duty cycle, allows the control unit 102 to turn the ultraviolet lamp 60 on and
off
through the remaining components of the inductively coupled ballast circuit
103, as
will be set forth below. The control circuit 142 also prevents false
triggering and
allows positive control if the control unit 102 fails.
As illustrated in Fig. 5, the first DC power source 180 and the second DC
power source 184 provide power to the circuits depicted in Fig. 5. Those
skilled in
the art of electronics would recognize that DC power supply circuits are well
known
in the art and beyond the scope of the present invention. For the purposes of
the
present invention, it is important to note that such circuits exist and are
capable of
being designed to produce various DC voltage values from a given AC or DC
power
source. In the preferred embodiment of the invention, a+14VDC and a +19VDC
signal is used, as indicated throughout the figures. Those skilled in the art
would
recognize that the circuits disclosed in Fig. 5 could be designed to operate
on different
DC voltage levels and that these values should not be construed as a
limitation on the
present invention.
In the preferred embodiment depicted in Fig. 5, the output of the control
circuit 142 is connected with an interlock circuit 190 to prevent the
ultraviolet lamp
60 from becoming energized if the water treatment system 10 is not properly
assembled. The interlock circuit 190 includes a magnetic interlock sensor 192,
a
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plurality of resistors 193, 194, 196, 198, 200, 202, 204, a transistor 206 and
a diode
208. Referring to Fig. 1, in the preferred embodiment of the invention, the
magnetic
interlock sensor 192 is positioned so that if the top shroud 24 is not
securely
positioned on the inner sleeve shroud 26, the water treatment system 10 will
not
energize the ultraviolet lamp 60. However, those skilled in the art would
recognize
that the magnetic interlock sensor 192 may be placed in other convenient
places of the
water treatment system 10 as well.
Referring to Fig. 5, the magnetic interlock circuit 190 operates by directing
the
output of the control circuit 142 to the ground connection 182, through
transistor 206,
1o if the magnetic interlock sensor 192 detects that the water treatment
system 10 is not
assembled properly, as set forth above. As those skilled in the art would
recognize, if
the water treatment system 10 is not assembled properly, the output of the
magnetic
interlock sensor 192 causes the current flowing through resistors 194, 196 and
198 to
energize the gate of transistor 206, which thereby shorts the output signal of
the
control circuit 142 to the ground connection 182. The magnetic interlock
sensor 192
is powered by the second DC power source 184 through resistor 193 and is also
connected with the ground connection 182. In addition, the magnetic interlock
sensor
192 sends a signal to the control unit 102, through the combination of
resistors 200,
202 and 204, diode 208, first DC power source 180 and second DC power source
184.
This signal also allows the control unit 102 to determine when the water
treatment
assembly 10 is not assembled properly. To that end, the interlock circuit 190
provides
two methods of ensuring that the ultraviolet lamp 60 is not energized if the
water
treatment system 10 is not assembled properly.
Referring once again to Fig. 5, the oscillator 144 provides electrical signals
that energize the driver 146 while the water treatment system 10 is treating a
flow of
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water. The oscillator 144 begins operating immediately once an electrical
signal is
sent from the control unit 102, through control circuit 142, as set forth
above. The
preferred oscillator 144 comprises an operational amplifier 210, a linear bias
resistor
212, a buffer circuit 214, a buffer feedback protect circuit 216 and a
positive feedback
circuit 218. During operation, the operational amplifier 210 receives input
signals
from the control circuit 142, the linear bias resistor 212 and the positive
feedback
circuit 218. The operational amplifier 210 is also connected with the second
DC
power source 184 and the ground connection 182, which energizes the
operational
amplifier 210.
As illustrated in Fig. 5, the preferred buffer circuit 214 comprises a first
transistor 220, a second transistor 222 and a pair of resistors 224, 226. The
output of
operational amplifier 210 is connected with the gates of transistors 220, 222,
thereby
controlling operation of transistors 220, 222. The second DC power source 184
is
connected with resistor 224, which is also connected with collector of
transistor 220.
The emitter of transistor 220 is connected with resistor 226, the emitter of
transistor
222 and the input of the driver 146. The collector of transistor 222 is
connected with
ground connection 182. During operation, the buffer circuit 214 buffers the
output
signal from the operational amplifier 210 and prevents load changes from
pulling the
frequency of oscillation. In addition, the buffer circuit 214 increases the
effective
gain of the inductively coupled ballast circuit 103, which helps ensure a
quick start of
the oscillator 144.
The buffer feedback protect circuit 216 comprises a pair of diodes 228, 230
that are electrically connected with the output of the buffer circuit 214 by
resistor 226.
As illustrated in Fig. 5, the second DC power source 184 is connected with the
cathode of diode 228. The anode of diode 228 and the cathode of diode 220 are
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connected with resistor 226 and the linear bias resistor 212. The linear bias
resistor
212 provides bias feedback signals to the negative input of operational
amplifier 210.
In addition, the anode of diode 230 is connected with ground connection 182,
which
completes the buffer feedback protect circuit 216. The buffer feedback circuit
216
protects the buffer circuit 214 from drain to gate Miller-effect feedback
during
operation of the water treatment system 10.
As illustrated in Fig. 5, the positive feedback circuit 218 includes a first
multi-
winding transformer 232, a plurality of resistors 234, 236, 238, a pair of
diodes 240,
242, and a capacitor 244. The secondary of the transformer 232 is electrically
connected with the output of the half-bridge switching circuit 148 and the
input of the
series resonant tank circuit 150 as illustrated in Fig. 5. In addition, one
winding from
each secondary coil of the multi-winding transformer 232 is connected to
another
winding of the opposite secondary coil in the transformer 232.
The first primary winding of transformer 232 is electrically connected with
resistors 234, 236, 238, the diodes 240, 242 and the positive input of the
operational
amplifier 210. The second primary winding of the transformer 232 is connected
with
resistor 238, the cathode of diode 242, the anode of diode 240 and capacitor
244. As
such, resistor 238 and diodes 242, 244 are connected in parallel with the
first and
second primary windings of transformer 232, as illustrated in Fig. 5.
Capacitor 244 is
also electrically connected with the negative input of operational amplifier
210. In
addition, resistor 234 is connected with the second DC power source 184 and
resistor
236 is connected with the ground connection 182. Resistors 234, 236 and 238
protect
the operational amplifier 210 from current overload and diodes 240, 242 clip
the
feedback signal that is sent to the input of the operational amplifier 210.
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During operation, the oscillator 144 receives signals from the control circuit
142 that charges capacitor 244, which, in turn, sends an electrical signal to
the
negative input of the operational amplifier 210. The output of the operational
amplifier 210 is electrically directed to the driver 146, which energizes the
half-bridge
switching circuit 148. As illustrated in Fig. 5, the transformer 232 is
connected in this
current path and sends electrical signals back through resistors 234, 236 and
238,
which limits the current, and eventually directs the electrical signal back to
the inputs
of the operational amplifier 210. Transformer 232 allows the oscillator 144 to
self-
resonate and the inductively coupled ballast circuit 103 remains oscillating
until the
control unit 102 shuts the water treatment system 10 down or transistor 206 of
the
interlock circuit 190 pulls the input to the oscillator 1441ow.
Referring once again to Fig. 5, the output of the oscillator 144 is
electrically
connected with the driver 146, which comprises the first primary winding of a
second
multi-winding transformer 246 in the preferred embodiment. The second
transformer
246 is the preferred driver 146 because the phasing arrangement of the
transformer
246 insures that the half-bridge switching circuit 148 will be alternately
driven, which
avoids shoot-through conduction. A double arrangement of capacitors 248, 250
is
electrically connected with the second primary winding of transformer 246,
thereby
preventing DC current overflow in the transformer 246. Capacitor 246 is also
connected with the ground connection 182 and capacitor 250 is also connected
with
the second DC power source 184.
Both secondary coils of transformer 246 are electrically connected with the
half-bridge switching circuit 148, which receives energy from transformer 246
during
operation. The half-bridge switching circuit 148, which is also illustrated in
Fig. 5, is
electrically arranged as a MOSFET totem pole half-bridge switching circuit 252
that
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is driven by both secondary coils of transformer 246. The MOSFET totem pole
half-
bridge switching circuit 252 includes a first MOSFET transistor 254 and a
second
MOSFET transistor 256 that provide advantages over conventional bipolar
transistor
switching circuits. Energy is transferred from the driver 146 to the MOSFET
transistors 254, 256 through a plurality of resistors 258, 260, 262, 264. The
MOSFET
transistors 254, 256 are designed to soft-switch at zero current and exhibit
only
conduction losses during operation. The output generated by MOSFET transistors
254, 256 is more in the form of a sine wave that has fewer harmonics than that
generated by traditional bipolar transistors. Using MOSFET transistors 254,
256 also
provides advantages by reducing radio frequency interference that is generated
by the
MOSFET transistors 254, 256 while switching during operation.
In the preferred half-bridge switching circuit 148 depicted in Fig. 5, the
first
secondary coil of transformer 246 is connected with resistor 258 and resistor
260.
The second secondary coil of transformer 246 is connected with resistor 262
and
resistor 264. Resistor 260 is connected with the gate of MOSFET transistor 254
and
resistor 264 is connected with the gate ofMOSFET transistor 256. As
illustrated, the
first secondary coil of transformer 246 and resistor 258 are connected with
the emitter
of MOSFET transistor 254. The second secondary coil of transformer 246 and
resistor 264 are connected with the gate of MOSFET transistor 256. The
collector of
MOSFET transistor 254 is connected with the second DC power source 184 and the
emitter of MOSFET transistor 254 is connected with the collector of MOSFET
transistor 256. The emitter of MOSFET transistor 256 and resistor 262 are
connected
with the ground connection 182.
A further benefit of the driver 146 is that multi-winding transformer 246 is a
very convenient way to apply gate drive voltage to the MOSFET transistors 254,
256
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that exceeds the second DC power source 184, which is a condition necessary
for
effective operation. The MOSFET transistors 254, 256 provide further
advantages
because they have diodes inherent in their design that protect the MOSFET
totem pole
half-bridge switching circuit 252 from load transients. In addition, over-
voltages
reflected from the series resonant tank circuit 150, by changes in load, are
returned to
supply rails by the inherent diodes within MOSFET transistors 254, 256.
Referring to Fig. 5, the output of the half-bridge switching circuit 148 is
connected with the input of the series resonant tank circuit 150, which, in
turn,
inductively energizes the secondary coil 52 of the ultraviolet lamp assembly
14. As
set forth above, in the preferred embodiment of the invention, the positive
feedback
circuit 218 of the oscillator 144 is connected with the output of the half-
bridge
switching circuit 148 and the input of the series resonant tank circuit 150 to
provide
feedback to operational amplifier 210 of the oscillator 144 during operation.
However, the output of the half-bridge switching circuit 148 is connected with
the
input of the series resonant tank circuit 150 by the secondary coil of
transformer 232
as illustrated in Fig. 5.
Referring to Fig. 5, the series resonant tank circuit 150 comprises an
inductive
coupler 270, the parallel combination of a pair of tank capacitors 271, 272, a
pair of
diodes 274, 276 and a capacitor 278. The inductive coupler 270 is connected
with the
secondary coil of transformer 232 and between tank capacitors 271, 272. Tank
capacitor 271 is also connected with the second DC power source 184 and tank
capacitor 272 is also connected with the ground connection 182. In addition,
tank
capacitor 271 and the second DC power source 184 are connected with the anode
of
diode 274. The cathode of diode 274 and capacitor 278 are both connected with
the
second DC power source 184. Capacitor 278 is connected with the anode of diode
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276 and the ground connection 182. Tank capacitor 272 is also connected the
cathode
of diode 276.
It is important to note that the series resonant tank circuit 150 sees all of
the
stray inductances of the component combination of the inductively coupled
ballast
circuit 103. This is important because the stray inductance, which is the
combined
inductance seen by the series resonant tank circuit 150, will limit the power
transfer
dramatically to the load under any condition outside resonance. The inductance
of the
secondary coil 52 and the resonant lamp circuit 152 are also reflected
impedance
values that help determine and limit the power that is delivered to the
secondary coil
52 of the ultraviolet lamp assembly. In general, brute force
oscillator/transformer
combinations have power transfer limits because of stray and reflected
inductance. In
other words, the inductance of transformers and capacitors appears in series
with the
load.
The frequency of operation for the series resonant tank circuit 150 is set
near
100KHz, which is determined by the inductance of the inductive coupler 270 and
the
parallel capacitance value of tank capacitors 271, 272, which are 0. luF
capacitors in
the preferred embodiment. Tank capacitors 271, 272 must have low dissipation
factors and be able to handle high levels of current, which is about 14 amps
at start
up. This resonant frequency may be adjusted up or down and has been selected
only
for convenient component selections.
The inductive coupler 270 includes 10 turns of wire to generate the power
required to inductively energize the secondary coil 52 in the ultraviolet lamp
assembly 14. The inductive coupler 270 is positioned in the outlet cup 36 (see
Fig.
2A) of the water treatment system 10 and wire is wrapped around the outlet cup
36 in
a diameter of about 3.5 inches. In the preferred embodiment, litz wire is used
for the
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inductive coupler 270 because litz wire is especially efficient in both
performance
and operating temperature, due to a fringing effect caused by the high
currents that
are created while operating at 100kHz. As set forth above, the inductive
coupler 270
inductively energizes the secondary coil 52 of the ultraviolet lamp assembly
unit 14
during operation.
Referring to Fig. 2A, the secondary coil 52 of the ultraviolet lamp assembly
unit 14 is positioned in the outlet cup 36 and the inner sleeve shroud 26 when
the
water treatment system 10 is assembled. In the preferred embodiment, the
secondary
coil 52 has 55 turns of small diameter wire that is wrapped around the
secondary coil
52 in a diameter of about two inches. It is important to note that the
coupling between
the outlet cup 36 and the base subassembly 50, which houses the secondary coil
52, is
designed to be very tolerant of gaps and misalignment. In fact, gaps are used
to
adjust the coupling coefficient, thereby adjusting the operating point of the
ultraviolet
lamp 60. In addition, the present invention provides further advantages by
providing
a coupling that does not require special contacts for the ultraviolet lamp
assembly 14
because of the inductively coupled ballast circuit 103.
As readily apparent to those skilled in the art, the inductively coupled
ballast
circuit 103 set forth above may be readily incorporated into other lighting
systems and
provides advantages over prior art ballast circuits because it drives lamps
without
requiring a physical connection. This allows the ultraviolet lamp assembly 14
to be
readily replaced once the ultraviolet lamp 154 has reached the end of its
operational
life. The inductively coupled ballast circuit 103 is capable of
instantaneously
energizing several different styles of lamps or bulbs.
Referring once again to Fig. 5, the ballast feedback circuit 122 is
electrically
connected with the inductive coupler 270 of the series resonant tank circuit
150 and
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the control unit 102. The ballast feedback circuit 122 provides feedback to
the control
unit 102 while the inductively coupled ballast circuit 103 is driving the
ultraviolet
lamp 60. This allows the control unit 102 to monitor the energy being provided
by
the inductive coupler 270 to the secondary coil 52 of the ultraviolet lamp
assembly
14. This provides the control unit 102 with the ability to determine if the
ultraviolet
lamp 60 is on or off and also, in other embodiments, the amount of current and
voltage being applied to the ultraviolet lamp 60.
As depicted in Fig. 5, the ballast feedback circuit 122 includes an
operational
amplifier 280, a pair of resistors 282, 284, a pair of diodes 286, 288 and a
capacitor
1o 290. The signal from the series resonant tank circuit 150 is directed to
the anode of
diode 286. The cathode of diode 286 is connected with capacitor 290 and
resistor
282. In addition, resistor 282 is connected with the anode of diode 288,
resistor 284
and the positive input of operational amplifier 280. Resistor 284 is also
connected
with the positive input of operational amplifier 280 and the first DC power
source
180. Capacitor 290 is also connected with the first DC power source 180, while
the
cathode of diode 288 is connected with the second DC power source 184. The
negative input of operational amplifier 280 is connected directly with the
output of
operational amplifier 280. The output of operational amplifier 280 is
connected with
the control unit 102, thereby providing the feedback signal from operational
amplifier
280 to the control unit 102.
Referring to Fig. 6, the ultraviolet lamp assembly 14 includes the ultraviolet
lamp 60, the resonant lamp circuit 152 and the secondary coil 52. The
ultraviolet
lamp 60 comprises a pair of bulbs 300, 302 and a pair of filaments 304, 306.
The
bulbs 300, 302 are held together with an upper connection bracket 308 and a
lower
connection bracket 310. The secondary coil 52 is connected with the resonant
lamp
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circuit 152, which, in turn, is connected with the filaments 304, 306 of the
ultraviolet
lamp 60. The resonant lamp circuit 152 comprises a capacitor 312 that is
electrically
connected with a starter circuit 314.
Although an ultraviolet lamp assembly 14 is set forth in the preferred
embodiment of the present invention, as previously set forth, those skilled in
the art
would recognize that other electromagnetic radiation emitting assemblies may
be used
in the present invention. For example, the ultraviolet lamp assembly 14 may
use a
pulsed white light lamp or a dielectric barrier discharge lamp to deactivate
microorganisms in the flow of water. Those skilled in the art would recognize
that the
inductively coupled ballast circuit 103 may be used to drive various types of
electromagnetic radiation emitting devices that could be used in the present
invention.
As such, the present invention should not be construed to only cover water
treatment
systems that use an ultraviolet lamp assembly 14 that includes ultraviolet
lamps 300.
As illustrated in Fig. 7, the starter circuit 314 comprises a bridge rectifier
circuit 320, a silicon-controlled rectifier 322, a series arrangement of
diodes 324, 326,
328, 330, a triac 332, a plurality of transistors 334, 336, a plurality of
resistors 338,
340, 342, 344, 346 and a plurality of capacitors 348, 350. As those skilled in
the art
would recognize, the triac 332 may be any equivalent device, such as a FET
transistor
or a silicon controlled rectifier. In addition, those skilled in the art would
recognize
that the bridge rectifier circuit 320 comprises a plurality of diodes 352,
354, 356, 358
that are connected with the filaments 304, 306 of the ultraviolet lamp 60.
Referring to Fig. 7, the bridge rectifier circuit 320 is connected with
silicon-
controlled rectifier 322, resistor 338 and the ground connection 182. Silicon-
controlled rectifier 322 is also connected with the series arrangement of
diodes 324,
326, 328, 330 and the triac 332, which are both also connected with the ground
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connector 182. Resistor 338 is connected with triac 332, resistor 340 and
resistor 342.
Resistor 340 is connected with the collector of transistor 334, the gate of
transistor
336, capacitor 348 and resistor 344. Capacitor 348 and resistor 344 are
further
connected with the ground connection 182. Resistor 342 is connected with the
emitter
of transistor 336 and capacitor 350, which is also connected with the ground
connection 182. Triac 332 is connected with the emitter of transistor 334, and
the
gate of transistor 334 is connected with the collector of transistor 336 and
resistor
346. Resistor 346 is connected with the ground connection 182 to complete the
starter circuit 314.
Referring back to Fig. 6, during operation, capacitor 312 changes and limits
the current supplied to the ultraviolet lamp 60 from the secondary coil 52 by
changing
the reflected impedance of the ultraviolet lamp 60 through the inductive
coupler 270
(see Fig. 5) of the series resonant tank circuit 150. The starter circuit 314
is designed
to short filaments 304, 306 during start-up, thereby causing maximum preheat
of the
bulbs 300, 302. This allows the ultraviolet lamp 60 to strike maximum
dispersion of
the mercury in bulbs 300, 302, thereby causing maximum intensity and
delivering the
highest dose of ultraviolet light to the water as it passes through the
ultraviolet lamp
assembly 14. In other words, the starter circuit 314 is designed so that the
ultraviolet
lamp 60 instantly turns on at maximum intensity. The placement of mercury in
bulbs
300, 302 is important for maximum output. When the mercury condenses within
the
plasma path, the mercury is dispensed more evenly throughout bulbs 300, 302.
The
faster dispersion also allows quicker peak intensity, thereby providing the
ability to
give the flow of water a faster, more intense dose of ultraviolet light at
start-up.
Referring to Fig. 2B, the 0-ring 62 acts as a heat sink and is purposefully
placed between the path of water, which flows through the pair of quartz tubes
58,
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and the ultraviolet lamp 60 plasma path to allow the mercury to condense
within the
plasma path for improved instant ultraviolet light output. As the ultraviolet
lamp 60 is
energized, the full-circuit voltage potential is applied across capacitor 312,
filaments
304, 306 and the starter circuit 314. Because of the low impedance value of
the
filaments 304, 306 and the starter circuit 314, which acts as a short at start-
up, the
current is high for maximum preheat of the ultraviolet lamp 60. This causes
the
preheat of the ultraviolet lamp 60 to disperse some initial mercury at start-
up. When
the starter circuit 314 heats up, the starter circuit 314 RC time constant
releases the
shorting device, which is the triac 332 in the preferred embodiment, thereby
providing
lo full voltage across the filaments 304, 306. The starter circuit 314 allows
a better start
than a thermister because thermisters consume more energy after opening and do
not
open as quickly.
Referring to Fig. 8, the preferred radio frequency identification system 124
is
illustrated electrically connected with the control unit 102. The radio
frequency
identification system 124 uses a base station to communicate with the
ultraviolet light
radio frequency identification transponder 126 and the filter radio frequency
identification transponder 128. The radio frequency identification system 124
allows
contactless reading and writing of data, which is transmitted bidirectionally
between
the base station 360 and the transponders 126, 128. In the preferred
embodiment, the
radio frequency identification system 124 is manufactured by TEMIC
Semiconductors under model number TR5551 A-PP.
The radio identification system 124 is used by the control unit 102 to keep
track of information specific to each ultraviolet lamp assembly 14 and filter
assembly
16. As previously set forth, the ultraviolet lamp assembly 14 and the filter
assembly
16 are both designed to be readily replaceable. Since the ultraviolet light
radio
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frequency identification transponder 126 and the filter radio frequency
transponder
128 are located in the ultraviolet lamp assembly 14 or the filter assembly 16,
these
devices are never separated, which allows the control unit 102 to read and
write
information to and from the transponders 126, 128 through the base station
360.
Referring once again to Fig. 8, the ultraviolet light radio frequency
identification transponder 126 includes a transponder antenna 362 and a
read/write
IDIC (e5551) chip 364. The read/write IDIC (e5551) chip further includes an
EEPROM device 366 that physically stores the relevant information for each
respective ultraviolet lamp assembly 14 in memory locations. In the presently
preferred embodiment, the information consists of an ultraviolet lamp serial
number,
ultraviolet lamp start limit, ultraviolet lamp on-time limit, ultraviolet lamp
install time
limit, ultraviolet lamp cycle on-time, cycle mode low temperature, minimum
ultraviolet lamp on-time, ultraviolet lamp high-mode time and ultraviolet lamp
preheat time. In addition, the EEPROM device 366 in the ultraviolet light
radio
frequency identification transponder 126 allows the control unit 102 to keep
track of
ultraviolet lamp install time, ultraviolet lamp powered time, ultraviolet lamp
starts and
total ultraviolet lamp cold starts.
The ultraviolet lamp serial number is unique to each ultraviolet lamp assembly
14 and allows the control unit 102 of the water treatment system 10 to keep
track of
which ultraviolet lamp assemblies 14 have been installed in the water
treatment
system 10. The ultraviolet lamp start limit relates to the maximum allowed
number of
ultraviolet lamp starts and the ultraviolet lamp on-time limit relates to the
maximum
allowed installation time for the ultraviolet lamp 60. The ultraviolet lamp
install time
limit relates to the maximum allowable installation time for the ultraviolet
lamp
assembly 14 and the ultraviolet lamp cycle on-time relates to the minimum
amount of
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time the ultraviolet lamp 60 needs to be energized in low-temperature mode.
The
cycle mode low-temperature information relates to the temperature value to
which the
water treatment system 10 switches to low-temperature mode and the minimum
ultraviolet lamp on-time relates to the minimum amount of time the ultraviolet
lamp
60 must remain energized. The ultraviolet lamp high-mode time information
relates
to the amount of time the ultraviolet lamp 60 operates in high mode and the
ultraviolet
lamp preheat time relates to the amount of time the ultraviolet lamp 60 needs
to be
preheated.
As previously set forth, the EEPROM device 366 in the ultraviolet light radio
frequency identification transponder 126 is also capable of keeping track of
the
ultraviolet lamp install time. This information tracks the number of hours
that the
current ultraviolet lamp 60 has been plugged into the water treatment system
10. In
the preferred embodiment, for every minute the ultraviolet lamp 60 is plugged
into the
water treatment system 10, one minute is added to the total. The EEPROM device
366 also keeps track of the ultraviolet lamp powered time and the total
ultraviolet
lamp powered time. The ultraviolet lamp powered time and the total ultraviolet
lamp
powered time keeps track of the amount of time the ultraviolet lamp 60 has
been on so
that the control unit 102 can determine if a new ultraviolet lamp assembly 14
needs
installed. The ultraviolet lamp starts memory location stores the number of
times the
ultraviolet lamp 60 has been started, so that the control unit 102 can use
this
information to determine the end of life of the ultraviolet lamp 60. The total
ultraviolet lamp cold-starts memory location tracks the number of times the
ultraviolet
lamp 60 has been started when the ambient temperature sensor 114 indicates
that the
temperature is below a predetermined threshold value.
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Referring once again to Fig. 8, the filter radio frequency identification
transponder 128 includes a transponder antenna 368 and a read/write IDIC
(e5551)
chip 370. The read/write IDIC (e5551) chip 370 further includes an EEPROM
device 372 that physically stores the relevant information for each respective
filter
assembly 16 in memory locations. In the present preferred embodiment, the
relevant
information consists of a filter assembly serial number, a filter assembly
volume limit,
a filter assembly install time limit, and a plugged filter assembly threshold
percent.
The filter assembly serial number is used for unique identification of
different
filter assemblies 16 so that the control unit 102 can monitor which filter
assemblies 16
have been installed in the water treatment system 10. The filter assembly
volume
limit is associated with the volume of water the filter assembly is designed
to filter
before reaching the end of its useful life. The filter assembly install time
limit is used
by the control unit 102 to compute the remaining life of the filter assembly
16 based
on a predetermined allowable wet time. The plugged filter assembly threshold
percent contains the maximum allowable percentage of flow reduction for the
filter
assembly 16 before it needs replaced. This maintains the percent of
degradation of
the filter assembly 16 before a plugged filter assembly 16 error is initiated
by the
control unit 102.
The radio frequency identification system 124 includes the base station 360, a
coil 380, a plurality of diodes 382, 384, 386, 388, 390, 392, 394, a plurality
of
resistors 396, 398, 400, 402, 404, 406, 408, 410, 412, 414, 416, 418, 420 and
a
plurality of capacitors 422, 424, 426, 428, 430, 432, 434, 436 that are
electrically
connected as illustrated in Fig. 8. Those skilled in the art would recognize
that the
connection of the aforementioned components is well known to those skilled in
the
art. The radio frequency identification system 124 has been installed in the
water
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WO 00/78678 34 PCTIUSOO/16346
treatment system 10 using specifications set forth for the TK5551 A-PP, which
, as
previously set forth, is manufactured by TEMIC Semiconductors. For the purpose
of
the present invention, it is important to note that the base station 360 uses
the coil 380
for bidirectional communication with the ultraviolet light radio frequency
identification transponder 126 and the filter radio frequency identification
transponder
128.
The control unit 102 is electrically connected with the base station 360 so
that
the control unit 102 can communicate with the base station 360. As such, the
control
unit 102 is capable of reading and writing information to and from the
ultraviolet light
radio frequency identification transponder 126 and the filter radio frequency
identification transponder 128 through the base station 360 by using the coil
380. The
radio frequency identification system 124 is connected with the first DC power
source
180 and the second DC power source 184 as illustrated in Fig. 8, which
provides the
radio frequency identification system 124 with energy to function during
operation.
Those skilled in the art would recognize that other identification systems
could
be used with the present invention, such as contact-type identification
systems.
However, the present preferred embodiment of the invention uses a radio
frequency
identification system 124 because of the inherent benefits such a system
provides.
Referring to Fig. 9, the flow sensor circuit 104 is connected with the control
unit 102 to provide electrical signals to the control unit 102 indicating that
water is
flowing through the water treatment system 10. The flow sensor circuit 104
includes
a flow sensor 440, a plurality of capacitors 442, 444 and a resistor 446. The
flow
sensor is manufactured by Allegro under model number 3134. Capacitor 442 is
connected with the flow sensor 440, the first DC power source 180 and the
second DC
power source 184. The output of the flow sensor 440 is connected with the
parallel
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WO 00/78678 35 PCT/US00/16346
combination of resistor 446 and capacitor 444, before being connected with the
control unit 102. Resistor 446 and capacitor 444 are also connected with the
second
DC power source 184. During operation, the flow sensor 440 delivers electrical
signals to the control unit 102, which indicates that water is flowing in the
water
treatment system 10, thereby causing the control unit 102 to instantaneously
energize
the ultraviolet lamp 60. Those skilled in the art would recognize that several
variations exist on the disclosed flow sensor circuit 104 and that the
disclosed flow
sensor circuit 104 is provided by way of example only and should be not
construed as
a limitation of the present invention.
Referring to Fig. 10, the ambient light sensor circuit 108 comprises a
photosensitive diode 450, an operational amplifier 452, a plurality of
resistors 454,
456, 458, 460, a diode 462 and a capacitor 464 electrically connected as
illustrated.
For purposes of the present invention, it is sufficient to note that the
photosensitive
diode 450 provides electrical signals to the negative input of the operational
amplifier
452, which, in turn, conditions the signal for the control unit 102. The
ambient light
sensor circuit 108 is powered by the first DC power source 180 and the second
DC
power source 184. 10. Those skilled in the art would recognize that several
variations
exist on the design of ambient light sensor circuits 108 and that the
presently
disclosed preferred embodiment should not be construed as a limitation on the
present
invention.
Referring to Fig. 11, as previously set forth, the visible light sensor
circuit 110
is connected with the control unit 102 to provide electrical signals to the
control unit
102 corresponding to the intensity of the ultraviolet lamp 60 during
operation. In the
preferred embodiment, the visible light sensor circuit 110 comprises a
photosensitive
resistor 470, an operational amplifier 472, a diode 474, a plurality of
resistors 476,
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WO 00/78678 36 PCT/US00/16346
478, 480, 482, 484, 486 and a capacitor 488 electrically connected as depicted
in Fig.
11. In addition, the visible light sensor circuit 110 is powered by the first
DC power
source 180 and the second DC power source 184. Those skilled in the art would
recognize that the visible light sensor circuit 110 takes the electrical
signal generated
by the photosensitive resistor 470 and amplifies it with the operational
amplifier 472,
before being directed to the control unit 102. Further, those skilled in the
art would
recognize that the design of visible light sensor circuits 110 can vary and
that the
disclosed ultraviolet light sensor circuit 110 is by way of example only and
should not
be construed as a limitation of the present invention.
Referring to Fig. 12, as previously set forth, the preferred ambient
temperature
sensor circuit 114 is connected with the control unit 102 to provide the
control unit
102 with electrical signals that change with corresponding changes in the
ambient
temperature. The ambient temperature sensor circuit 114 comprises a thermistor
490,
an operational amplifier 492, a plurality of resistors 494, 496, 498 and a
capacitor 500
that are electrically connected as illustrated in Fig. 12. During operation,
the voltage
drop across thermistor 490 changes as the ambient temperature changes, thereby
causing the electrical signal that is sent from the output of the operational
amplifier
492 to the control unit 102 to either increase or decrease. Those skilled in
the art
would recognize that the design of ambient temperature sensor circuits 114 can
vary.
The preferred ambient temperature sensor circuit 114 illustrated in Fig. 12 is
by way
of example only and should not be construed as a limitation of the present
invention.
Referring to Fig. 13, as previously set forth, the preferred audio generation
circuit 116 is connected with the control unit 102 for generating audible
enunciations
in response to predetermined system states. The preferred audio generation
circuit
116 comprises a piezoelectric element 510, a plurality of transistors 512,
514, 516, a
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WO 00/78678 37 PCT/US00/16346
plurality of resistors 518, 520, 522, 524, 526, 528, 530, 532, 534, a
plurality of
capacitors 536, 538 and a diode 540, which are electrically connected as
depicted in
Fig. 13. As readily apparent to those skilled in the art, the control unit 102
is capable
of energizing the piezoelectric element 510, thereby causing the piezoelectric
element
510 to generate audible tones through vibrations. Those skilled in the art
would
recognize that several devices and circuits exist that are capable of
generating audible
tones. The presently disclosed audio generation circuit 116 is by way of
example
only and likewise should not be construed as a limitation of the present
invention.
Referring to Fig. 14, as previously set forth, the communications port 120 is
connected with the control unit 102. The communications port 120 is used by
the
control unit 102 to communicate bidirectionally with a peripheral device (not
shown),
such as a personal computer or a hand-held device. In the preferred
embodiment, the
communications port 120 comprises a plurality of zenar diodes 550, 552, 554
and a
plurality of resistors 556, 558,560, 562, 562, 566, 568, 570, which are
electrically
connected as illustrated in Fig. 14. The first DC power source 180 and the
second DC
power source 184 provide power to the communications port 120. The
communications port 120 is designed to use the RS-232 communications standard,
as
well known in the art. A port connector 572 is provided so that the peripheral
device
can be connected with the communications port 120. Those skilled in the art
would
recognize that different types of communication ports may be used and are
beyond the
scope of the present invention. To that end, the preferred communications port
120
disclosed herein is by way of example only and should not be construed as a
limitation of the present invention.
While the invention has been described in its currently best known modes of
operation and embodiments, other modes and embodiments of the invention will
be
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WO 00/78678 38 PCT/USOO/16346
apparent to those skilled in the art and are contemplated. In addition,
although the
preferred embodiment of the present invention is directed to a water treatment
system
10, those skilled in the art would recognize that the present invention may be
readily
incorporated in several different types of fluid treatment systems.
