Note: Descriptions are shown in the official language in which they were submitted.
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FLUID TREATMENT DEVICE AND METHOD
In one of its aspects, present invention relates to a fluid treatment
device. In another of its aspects, the present invention relates to method
for treating a fluid.
Fluid treatment devices and systems are known. For example,
United States patents 4,482,809, 4,872,980, 5,006,244 and 5,418,370
(all assigned to the assignee of the present invention)
all describe gravity
fed fluid treatment systems which employ ultraviolet (UV) radiation to
inactivate microorganisms present in the fluid.
The devices and systems described in the '809, '980 and '244
patents generally include several UV lamps each of which are mounted
within sleeves extending between two support arms of the frames. The
frames are immersed into the fluid to be treated which is then irradiated
as required. The amount of radiation to which the fluid is exposed is
determined by the proximity of the fluid to the lamps. One or more UV
sensors may be employed to monitor the UV output of the lamps and the
fluid level is typically controlled, to some extent, downstream of the
treatment device by means of level gates or the like. Since, at higher
flow rates, accurate fluid level control is difficult to achieve in gravity
fed systems, fluctuations in fluid level are inevitable. Such fluctuations
could lead to non-uniform irradiation in the treated fluid.
However, disadvantages exist with the above-described systems.
Depending on the quality of the fluid which is being treated, the sleeves
surrounding the UV lamps periodically become fouled with foreign
materials, inhibiting their ability to transmit UV radiation to the fluid.
When fouled, at intervals which may be determined from historical
operating data or by the measurements from the UV sensors, the sleeves
must be manually cleaned to remove the fouling materials. Regardless
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of whether the UV lamp frames are employed in an open, channel-like
system or a closed system, cleaning of the sleeves is impractical.
In open, channel-like systems, the modules comprising the sleeves
are usually removed from the channel and immersed in a separate tank
containing a suitable cleaning fluid. In closed systems, the device must
be shut down and the sleeves are thereafter cleaned by charging with a
suitable cleaning fluid or by removal of the lamps in the manner
described for the open, channel-like systems. In either type of system,
the operator must accept significant downtime of the system and/or
invest significant additional capital to have in place sufficient redundant
systems with appropriate control systems to divert the flow of fluid from
the systems being cleaned.
The system described in the '370 patent is a significant advance
in the art in that it obviates a number of disadvantages deriving from the
devices and systems '809, '980 and '244 patents. Unfortunately, the
system described in the '370 patent is ideally suited for use in an open,
channel-like system and is not readily adaptable to be used in a
completely closed system where the flow of fluid is fed under pressure
in a pipe.
It would be desirable to have a fluid treatment device which can
be readily adapted to be treat a flow of fluid fed under pressure in a pipe
or like enclosure. It would be further desirable if such a device was
relatively easy to clean or keep clean during use.
It is an object of the present invention to provide a novel fluid
treatment device which obviates or mitigates at least one of the
disadvantages of the prior art.
It is another object of the present invention to provide a novel
method for treating a fluid which obviates or mitigates at least one of the
disadvantages of the prior art.
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Accordingly, in one of its aspects, the present invention provides
a fluid treatment device comprising a housing for receiving a flow of
fluid, the housing comprising a fluid inlet, a fluid outlet, a fluid
treatment zone disposed between the fluid inlet and the fluid outlet, and
at least one radiation source module disposed in the fluid treatment zone,
the at least one radiation source module comprising a radiation source
sealably connected to a leg, the leg sealably mounted to the housing, the
radiation source being disposed substantially parallel to the flow of fluid.
In another of its aspects, the present invention provides a method
of treating a fluid in a housing comprising a fluid inlet, a fluid outlet, a
fluid treatment zone disposed between the fluid inlet and the fluid outlet,
the fluid treatment zone having at least one radiation source disposed
therein, the method comprising the steps of:
(i) providing a flow of the fluid to the fluid inlet;
(ii) feeding the flow of fluid from the fluid inlet to the fluid
treatment zone in a manner substantially parallel to the at least one
radiation source;
(iii) irradiating the flow of fluid in the fluid treatment zone; and
(iv) feeding the flow of fluid to the fluid outlet;
wherein the flow of fluid through the fluid inlet, the fluid outlet
and the fluid treatment zone is substantially collinear.
Thus, the present fluid treatment device and method relate to a
closed system for treatment of a fluid. As used throughout this
specification, the term "closed system", in relation to treatment of a
fluid, is intended to encompass a system in which the flow of fluid is
pressurized and substantially completely contained in an enclosure
throughout treatment. Thus, open, channel-like systems are outside the
scope of the present invention since, in the operation of such systems the
level of water in the channel and/or treatment zone can vary. The
source of pressurization of the flow of fluid is not particularly restricted.
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For example, the pressure can be generated by a pump or by the action
of gravity.
Ideally, the present fluid treatment device and method may be
used "in-line" in conventional water piping. Depending on the particular
application, the piping can be up to 4 in. diameter for domestic
applications, or 1 ft. to 3 ft. diameter or more for municipal
applications.
Embodiments of the present invention will be described with
reference to the accompanying drawings, in which:
Figure 1 illustrates, a side elevation, partially cut away, of a
conventional closed system for treatment of a fluid;
Figure 2 illustrates an end view of a first embodiment of a fluid
treatment device in accordance with the present invention;
Figure 3 illustrates a section along line III-III in Figure 2;
Figure 4 illustrates an end view of a second embodiment of a
fluid treatment device in accordance with the present invention;
Figure 5 illustrates a section along line V-V in Figure 4;
Figure 6 illustrates an end view of a third embodiment of a fluid
treatment device in accordance with the present invention;
Figure 7 illustrates a section along line VII-VII in Figure 6;
Figure 8 illustrates is an expanded view of the area designated C
in Figure 3;
Figure 9 illustrates is section along line IX-IX in Figure 8; and
Figure 10 illustrates a side elevation, partially cut away, of a
radiation source module used in the devices illustrated in Figures 2-9.
In the Figures, like reference numerals from one Figure to
another are intended to designated like parts.
For clarity, a brief description of a prior art, closed system, fluid
treatment device will be presented before discussing the present
invention.
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Figure 1 illustrates such a device which is conventionally
available. Thus, with reference to Figure 1, there is illustrated a fluid
treatment device 10 having a housing 12. Housing 12 comprises a fluid
inlet 14 having an inlet flange 16 and a fluid outlet 18 having an outlet
flange 20. Contained within housing 12 is a plurality of ultraviolet (UV)
lamps 22, with each lamp surrounded by a quartz sleeve 24. Housing
12 comprises a first flange 26 to which is connected a first plate 28.
The connection between first flange 26 and first plate 28 is made by a
number of bolt/nut combinations 30, 32 and a seal (not shown) to
achieve a hermetic seal. First plate 28 is adapted to permit the
emergence of a wire 34 from each UV lamp 22. A boot 36 is connected
to first plate 28 allows emergence of each wire 34. Each wire 34 is
connected to a power supply (not shown) and control system (not shown)
in a conventional manner. Housing 12 further comprises a second
flange 38 to which is connected a second plate 40. The connection
between second flange 38 and second plate 40 is made by a number of
bolt/nut combinations 42, 44 and a seal (not shown) to achieve a
hermetic seal. The exact manner (not shown) by which the seals
between first flange 26 and first plate 28, and second flange 38 and
second plate 40, respectively, are achieved is within the purview of a
person skilled in the art.
In use, inlet flange 16 is connected to a suitable supply pipe (not
shown) and outlet flange 20 is connected to a suitable return pipe (not
shown). As depicted by arrow A, fluid to be treated enters housing 12
via fluid inlet 14. The fluid is exposed to radiation from UV lamps 22
and exits housing 12 via fluid outlet 18 as depicted by arrow B.
The design of fluid treatment device 10 is such that it suffers from
significant hydraulic head loss due to the fact that (i) the cross-sectional
area of fluid inlet 14 and the fluid outlet 20 of housing 12 is significantly
less than that of housing 12, and (ii) the flow of fluid flows a relatively
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tortuous path. This leads to the creation of dead zones 46, 48 within
housing 12 wherein the flow of fluid is negligible resulting in inefficient
and, in some cases, non-uniform treatment of fluid.
Accordingly, while the above-described prior art systems have
been successful, the present inventor has been concerned with improving
fluid treatment devices and systems to overcome some of these
disadvantages. The present invention will now be described with
reference to the remaining Figures.
With reference to Figures 2 and 3, there is illustrated a fluid
treatment system 200 comprising a fluid inlet 205, a fluid outlet 210 and
a fluid treatment zone 215 disposed in a housing 220. Disposed in
housing 220 are two radiation source modules 225. Each radiation
source module 225 is mounted to housing 220 by mounting plate 230
which will be described in more detail hereinbelow. Also disposed in
housing 220 are two radiation sensors 235. Emanating from each
radiation source module 225 is an electrical lead 240. Each of the
electrical leads 240 enters a junction box 245 from which a main
electrical conduit 250 emanates. Fluid inlet 205 includes an inlet flange
255 and fluid outlet 210 includes an outlet flange 260. Emanating from
each radiation sensor is an electrical lead 265. Each of the electrical
leads 265 enters a junction box 250 from which a main electrical conduit
(not shown) emanates.
Ideally, fluid treatment system 200 is constructed to be used in-
line in existing fluid (e.g. water) piping. Thus, for a given installation,
it is desirable to design fluid treatment zone 215 such that it has
substantially the same cross-sectional shape and dimension as the
existing piping. Inlet flange 255 and outlet flange 260 can be used to
facilitate installation of fluid treatment system 200 between mating
flanges in the existing piping. When the system is installed, it will be
apparent to those of skill in the art that fluid flow through fluid
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treatment zone 215 is parallel with respect to the lamps disposed in
radiation source module 225. This minimizes the occurrence of
hydraulic headloss in the flow of fluid and eliminates dead zones
resulting in more efficient treatment of the fluid.
With reference to Figures 4 and 5, there is illustrated a fluid
treatment system 300 comprising a fluid inlet 305, a fluid outlet 310 and
a fluid treatment zone 315 disposed in a housing 320. Disposed in
housing 320 are six radiation source modules 325. Each radiation
source module 325 is mounted to housing 320 by a mounting plate 330
which will be described in more detail hereinbelow. Also disposed in
housing 320 are two radiation sensors 335. Emanating from each
radiation source module 325 is an electrical lead 340. Each of the
electrical leads 340 enters a junction box 345 from which a main
electrical conduit 350 emanates. Fluid inlet 305 includes an inlet flange
350 and fluid outlet 310 includes an outlet flange 360. Emanating from
each radiation sensor is an electrical lead 365. Each of the electrical
leads 365 enters a junction box 370 from which a main electrical conduit
(not shown) emanates.
With reference to Figures 6 and 7, there is illustrated a fluid
treatment system 400 comprising a fluid inlet 405, a fluid outlet 410 and
a fluid treatment zone 415 disposed in a housing 420. Disposed in
housing 420 are sixteen radiation source modules 425. Each radiation
source module 425 is mounted to housing 420 by a mounting plate 430
which will be described in more detail hereinbelow. Also disposed in
housing 420 are two radiation sensors 435. Emanating from each
radiation source module 425 is an electrical lead 440. Each of the
electrical leads 440 enters a junction box 445 from which a main
electrical conduit 450 emanates. Fluid inlet 405 includes an inlet flange
450 and fluid outlet 410 includes an outlet flange 460. Emanating from
each radiation sensor is an electrical lead 465. Each of the electrical
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leads 465 enters a junction box 470 from which a main electrical conduit
(not shown) emanates.
The construction and use of the fluid treatment systems 300
(Figures 4 and 5) and 400 (Figures 6 and 7) may be effected in the same
manner as discussed hereinabove for fluid treatment system 200 (Figures
2 and 3).
With reference to Figures 8 and 9, mounting plate 230 is affixed
to housing 220 in the following manner. Initially, it will be apparent
that housing 220 comprises a suitably shaped aperture to receive each
radiation source module 225. The shape of the aperture is preferably
similar to that of mounting plate 230 and the size of the aperture is
smaller than that of mounting plate 230. A flange ring 275 sized larger
than and having the same shape as the aperture is affixed to housing 220
to define a notch in which a resilient 0-ring 280 is placed. Flange ring
275 has a plurality of upstanding bolts (not shown). Mounting plate 230
has a plurality of complementary apertures to receive the bolts on flange
ring 275. Mounting plate 230 also contains a backup plate 290 to form,
together with flange ring 275, a cavity for 0-ring 280. Torque bolts
285 are in threaded engagement with each of the upstanding bolts on
flange ring 275.
Thus, with reference to Figures 2, 3, 8 and 9, radiation source
module is installed in the following manner (see also Figure 7). The end
of radiation source module distal mounting plate 230 is inserted in an
aperture in housing 220. Mounting plate 230 is then positioned by
ensuring that the apertures therein receive the upstanding bolts on flange
ring 275. Torque nuts 285 are then tightened with sufficient force to
compress 0-ring 275 thereby providing a hermetic seal between fluid
treatment zone 215 and the exterior of housing 220.
With reference to the Figure 10, there is illustrated a detailed
view of a radiation source module 225. It will be appreciated by those
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of skill in the art the radiation source module 225 is similar to radiation
source modules 325 (Figures 4 and 5) and 425 (Figures 6 and 7). There
is detailed discussion of such a module in copending Canadian patent
application serial number 2,160,730, in the name of the present
inventor and applicant.
Thus, radiation source module comprises a support member
115, a radiation source assembly 120 extending from support member
115 and mounting plate 230 for affixing radiation source module 225 to
housing 220. Mounting plate 230 has a plurality of apertures 232 which
receive upstanding bolts from flange ring 275 (Figures 2, 3, 8 and 9).
Radiation source assembly 120 includes a concentric reducer 130
which can be welded to or made integral with support member 115.
Affixed to concentric reducer 130 is a ring 135 to which is affixed a
mounting sleeve 140. The end of mounting sleeve 140 distal concentric
reducer 130 has a threaded portion 145. Disposed within mounting
sleeve 140 is an inner sleeve 150 having a threaded portion 145 to which
is engaged a cap nut 160. Inner sleeve 150 comprises suitable notches
to receive a pair of resilient 0-rings 165,170. The end of inner sleeve
150 distal concentric reducer 130 abuts a resilient, tapered sealing ring
175. A threaded mounting nut 180 engages threaded portion 155 of
mounting sleeve 140 and abuts tapered sealing ring 175. Threaded
mounting nut 180 is provided with torquing receptacles 185 which
receive a suitable tool useful for torquing mounting nut 180 into sealing
engagement with mounting sleeve 140.
Disposed within inner sleeve 150 is an annular piezo-electric
ceramic transducer 190 which is a laminate structure made up of a
plurality of individual annular piezo-electric ceramic transducers (not
shown) adhered together. One end of transducer 90 abuts inner sleeve
150 and the other end of transducer 190 abuts, either directly or
indirectly, the open end of a quartz sleeve 195. As illustrated, the
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opposite end of quartz sleeve 195 is closed. Disposed within quartz
sleeve 195 is a radiation source 196. Ideally, the radiation source is an
ultraviolet lamp. The ultraviolet lamp is not particularly restricted and
the choice thereof is within the purview of a person skill in the art. A
pair of spacers 197 are disposed within quartz sleeve 195 and serve to
centre and hold in place radiation source 196 within quartz sleeve 195.
The electrical connection and control of radiation source 196 is
conventional and within the purview of a person skilled. in the art.
As described in copending Canadian patent application serial
number 2,160,730 radiation source
module 225 is self-cleaning by intermittent or continuous operation of
transducer 190 during irradiation of the flow of fluid. More
specifically, operation of transducer 190 results in reciprocal vibration
of quartz sleeve 195 in a direction substantially parallel to the elongate
axis of quartz sleeve 195. Such vibration may be effected by utilizing
a piezo-electric transducer, preferably a piezo-electric ceramic
traiisducer. Piezo-electric ceramic transducers have been conventionally
used in sonar applications. A suitable piezo-electric ceramic transducer
useful in the present radiation source module is commercially available
from EDO Corporation (Salt Lake City, Utah) and consists essentially
of a ceramic component which meets the specifications of U.S. Navy
Type 1(I) or U.S. Navy Type 3(III) . As will be apparent to those of
skill in the art, a ceramic meeting the specifications of U.S. Navy Type
1 is a hard lead zirconate titanate with a Curie point greater than about
3109C and a ceramic meeting the specifications of U.S. Navy Type 3 is
a very hard lead zirconate titanate with a Curie point greater than about
290 C. Detailed specifications of these ceramic specifications can be
found in published Department of Defense Military Standard DOD-STD
1376A(SH), dated February 28, 1984, the contents of which are hereby
incorporated by reference. Generally, the piezo-electric transducer,
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most preferably an annular piezo-electric transducer, is one which can
be operated at a frequency in the range of from about 1 kHz to about
100 kHz, preferably from about 10 kHz to about 20 kHz, more
preferably about 10 kHz to about 15 kHz.
Of course it will be appreciated by those of skill in the art that the
illustrated embodiments of the radiation source module may be varied to
suit the particular fluid treatment system without departing from the
spirit of the invention. For example, the number, type and arrangement
of sealing rings (i.e. 0-rings, tapered rings, etc.) can be varied while
maintaining a hermetic seal. Further, the use of in situ means to clean
the radiation source module is option. If in situ means to clean the
radiation source module is used, it may be a device other than the
vibration cleaning device described hereinabove. It should be
understood that, while exemplary embodiments of the present invention
have been described herein, the present invention is not limited to these
exemplary embodiments and that variations and other alternatives may
occur to those of skill in the art without departing from the intended
spirit and scope of the invention as defmed by the attached claims.
