Note: Descriptions are shown in the official language in which they were submitted.
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FLUID TREATMENT SYSTEM AND PROCESS
The present imrention relates to a method of treating fluid by
providing a gravity fed flow of fluid to an irradiation zone comprising
at least one radiation source and having a closed cross-section which
confines the flaw of fluid within a predefined maximum distance from
the at least one radiation source.
The present invention also relates to a novel method of cleaning
a radiation source assembly located within a fluid flow wherein the
exterior of the source is swept by a cleaning member containing an
appropriate cleaning fluid.
The present invention also relates to a navel system for treating
fluid by exposing it to radiation. Specifically, the present invention
relates to a novel gravity fed system for treating fluids comprising a
treatment zone which includes a irradiation zone configured to provide
a fixed fluid geometry relative to the radiation sources.
The present invention also relates to a navel radiation source
module for use in a fluid treatment system. Specifically, the module
includes one or more radiation source assemblies connected to a support
member and the support member is designed to permit insertion and
exfi~action of the module from the treatment system while the system is
in use. The module is designed such that the radiation source assembly
is prevented from contacting surfaces within the treatment zone of the
system while being installed or removed.
The present imendon also relates to a novel cleaning apparatus
for fluid treatment systems. Specifically, the cleaning apparatus includes
one or more cleaning members which may be swept aver the exterior of
radiation source assemblies within the fluid treatment system, the
cleaning members containing a suitable cleaning fluid which contacts the
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exterior of the radiation source assembly and loosens and/or removes
materials fouling the exterior of the radiation source assembly.
Fluid treatment systems are known. For example, United States
patents 4,482,809, 4,872,980 and 5,006,244 (assigned to the assignee of
the present invention), all describe gravity fed fluid treatment systems
which employ ultraviolet (UV) radiation.
Such systems include an array of UV lamp frames which 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, the output wattage of the lamps and the fluid's flow
rate past 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 levels are
inevitable. Such fluctuations could lead to non-uniform irradiation in the
treated fluid.
However, disadvantages exist with the above-described systems.
Depending upon 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.
If the UV lamp frames are employed in an open, channel-like
system, one or more of the frames may be removed while the system
continues to operate, and the removed frames may be immersed in a
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bath of suitable acidic cleaning solution which is air-agitated to remove
fouling materials. Of course, surplus or redundant sources of W
radiation must be provided (usually by including extra UV lamp frames)
to ensure adequate irradiation of the fluid being treated while one or
more of the frames has been removed for cleaning. Of course, this
required surplus W capacity adds to the expense of installing the
treatment system.
Further, a cleaning vessel containing cleaning solution into which
W lamp frames may be placed must also be provided and maintained.
Depending upon the number of frames to be cleaned at one time and the
frequency at which they require cleaning, this can also significantly add
to the expense of installing, maintaining and operating the treatment
system .
If the frames are in a closed system, removal of the frames from
the fluid for cleaning is usually impractical. In this case, the sleeves
must be cleaned by suspending treatment of the fluid, shutting inlet and
outlet valves to the treatment enclosure and filling the entire treatment
enclosure with the acidic cleaning solution and air-agitating the fluid to
remove the fouling materials. Cleaning such closed systems suffers
from the disadvantages that the treatment system must be stopped while
cleaning proceeds and that a large quantity of cleaning solution must be
employed to fill the treatment enclosure. An additional problem exists
in that handling large quantities of acidic cleaning fluid is hazardous and
disposing of large quantities of used cleaning fluid is difficult and/or
expensive. Of course open flow systems suffer from these two
problems, albeit to a lesser degree.
Indeed, it is the belief of the present inventor that, once installed,
one of the largest maintenance costs associated with prior art fluid
treatment systems is often the cost of cleaning of the sleeves about the
radiation sources.
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Another disadvantage with the above-described prior art systems
is the output of the UV lamps. Unfortunately, the UV lamps in the
prior art systems were required to be about five feet in length to provide
the necessary wattage of UV radiation. Accordingly, the UV lamps
were relatively fragile and required support at each end of the lamp.
This increased the capital cost of the system.
Further, due to the somewhat limited output wattage of the UV
lamps in the prior art systems, a great number of lamps were often
required. For example, certain prior art installations employ over 9,000
lamps. Such a high number of lamps adds to the above-mentioned costs
in cleaning lamps as well as the cost of maintaining (replacing) the
lamps.
It is an object of the present invention to provide a novel method
of treating a fluid by irradiation which obviates or mitigates at least one
1 S of the above-mentioned disadvantages of the prior art.
It is a further object of the present invention to provide a navel
fluid treatment system which obviates or mitigates at least one of the
above-mentioned disadvantages of the prior art.
According to one aspect of the present invention, there is
provided a method of treating a fluid comprising the steps of:
(i) providing a gravity fed flow of fluid to a fluid inlet;
(ii) feeding the flow of fluid from the fluid inlet to an irradiation
zone comprising at least one radiation source and having a closed cross-
section;
(iii) confining the flow of fluid within a predefined maximum
distance from the at least one radiation source;
(iv) exposing the flow of fluid to radiation from the radiation
source; and
(v) feeding the flow of fluid from step (iv) to a fluid outlet.
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According to another aspect of the present irnention, there is
provided a method of removal of fouling materials from a radiation
source in situ in a fluid treatment system, comprising the steps of:
(i) providing a supply of a cleaning fluid to a cleaning chamber;
(ii) moving the cleaning chamber into contact with at least a
portion of the radiation source for a predetermined time period, the
cleaning chamber maintaining the cleaning fluid in contact with the
portion; and
(iii) removing the cleaning chamber from contact with the portion
of the radiation source after the predetermined time period.
According to another aspect of the present invention, there is
provided a gravity fed fluid treatment system comprising a fluid inlet,
a fluid outlet, and an in~adiation zone disposed between the fluid inlet
and fluid outlet, the irradiation zone (i) including at least one radiation
source and, (ii) having a closed cross-section to confine fluid to be
treated within a predefined maximum distance from the at least one
radiation source assembly.
Preferably, the irradiation zone is disposed within a fluid
treatment zone including an inlet transition region and an outlet
transition region. The inlet transition region receives the fluid flow
from the fluid inlet and increases its velocity prior to entry thereof into
the irradiation zone. The outlet transition region receives the fluid flow
from the irradiation zone and decreases the velocity of the fluid flaw
prior to its entry into the fluid outlet. Thus, the fluid flaw velocity is
only elevated within the irradiation zone to reduce hydraulic head loss
of the fluid flaw through the system. It will be appreciated by those of
skill in the art that one or both of the inlet transition region and the
outlet transition region may comprise a tapered section (described in
more detail hereinbelow). Alternatively, a "bell-mouth" shaped inlet and
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outlet may be utilized. In either case, the underlying result is a
reduction in hydraulic head loss.
According to another aspect of the present invention, there is
provided a radiation source module for use in a fluid treatment system
comprising: a support member; at least one radiation source assembly
extending from said support member; and fastening means to affix the
radiation source module in the fluid treatment system.
According to yet another aspect of the present irnention, there is
provided a cleaning apparatus for a radiation source assembly in a fluid
treatment system, comprising: a cleaning sleeve engaging a portion of
the exterior said radiation source assembly and movable between a
retracted position wherein a first portion of said radiation source is
exposed to a flow of fluid to be treated and an extended position wherein
said first portion of said radiation source assembly is completely or
partially covered by said cleaning sleeve, said cleaning sleeve including
a chamber in contact with said first portion of said radiation source
assembly and being supplied with a cleaning solution suitable to remove
undesired materials from said first portion.
According to another aspect of the invention, there is provided a
radiation sensor assembly comprising: a sensor housing; a radiation
transmissive means within said housing and including a portion to be
exposed to a radiation source; a radiation sensor receiving radiation from
said transmissive means; and means to remove materials fouling said
portion.
As used herein, the term "gravity fed" encompasses systems
wherein the hydraulic head of the fluid is obtained from changes in the
altitude of the fluid. It will be understood that such systems comprise
both systems which are naturally gravity fed and systems wherein the
altitude of the fluid is altered via pumps or other mechanical means to
provide a gravity feed.
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Embodiments of the present invention will be described with
reference to the accompanying drawings, in which:
Figure 1 illustrates a side section of a prior art fluid treatment
device;
S Figure 2 illustrates an end section of the prior art fluid treatment
device of Figure 1;
Figure 3 illustrates a side section of a first embodiment of a
horizontal fluid treatment system in accordance with the present
invention;
Figure 4 illustrates a radiation source module for use with the
system of Figure 3;
Figure 5 illustrates an expanded view of the area indicated at A
in Figure 4;
Figure 6 illustrates a portion of another embodiment of a radiation
source module for use with the system of Figure 3;
Figure 7 illustrates an expanded view of the area indicated at B
in Figure 6;
Figure 8 illustrates a side section of a second embodiment of a
vertical fluid treatment system in accordance with the present invention;
and
Figure 9 illustrates a radiation sensor assembly.
For clarity, a brief description of a prior art fluid treatment device
will be presented before discussing the present irnendon. Figures 1 and
2 show a prior art treatment device as described in United States patent
4,482, 809. The device includes a plurality of radiation source modules
20, each including a pair of frame legs 24 with UV lamp assemblies 28
extending therebetween. As best shown in Figure 2, a plurality of lamp
modules 20 are arranged across a treatment canal 32 with a maximum
spacing between lamp modules 20 which is designed to ensure that the
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fluid to be treated is irradiated with at least a predetermined minimum
dosage of UV radiation.
While this system has been successful, as discussed above it
suffers from disadvantages in that the arrangement of the lamp modules
20 makes maintenance of the device relatively labour intensive.
Specifically, replacing lamps or cleaning the sleeves surrounding the
lamps is time consuming and expensive. Also, for treatment to continue
when a lamp module is remrnred, it is necessary to provide redundant
lamp modules to ensure that the fluid still receives the predefined
minimum dosage of radiation increasing the cost of the system. Further,
depending on the quality of the fluid and its flaw rate, significant
numbers of lamps and sleeves may be required per unit of fluid treated.
Another disadvantage of this prior art system is the difficulty in
controlling fluid level relative to lamp modules 20 at higher flow rates.
Accordingly, while the above-described prior art systems have
been successful, the present inventor has been concerned with improving
fluid treatment systems to Overcome some of these disadvantages. The
present irnention will now be described with reference to the remaining
Figures.
Referring now to Figure 3, a fluid treatment system in accordance
with the present invention is indicated generally at 100. The system 100
includes a main body 104 which is installed across an open fluid canal
108 such that the all of the fluid flow through canal 108 is directed
through a treatment zone 112. Main body 104 may be precast concrete,
stainless steel or any other material suitable for use with the fluid to be
treated and which is resistant to the type of radiation employed.
The lower surface of main body 104 includes a central section
116 which extends downward with leading and trailing inclined sections
120 and 124, respectively. A corresponding upraised central section 132
is located on a base 128 of canal 108 beneath central section 116 and
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r~~
includes leading and trailing inclined sections 136 and 140, respectively.
Central section 132 may be part of main body 104 or may be part of
base 128 (as illustrated).
As can be clearly seen in Figure 3, sections 116 and 132 form a
narrowed irradiation zone 144, while sections 120 and 136 form a
tapered inlet transition region and sections 124 and 140 form a tapered
outlet transition region.
As will be apparent, irradiation zone 144 presents a closed cross
section to the fluid to be treated. This provides a fixed geometry of the
fluid relative to irradiation sources (described hereinafter) to ensure that
the fluid is exposed to the predefined minimum radiation from the
irradiation sources. Those of skill in the art will appreciate that the
inner walls of irradiation zone 144 could be designed and configured to
substantially follow the contours of the portions of radiation source
modules 148 disposed therein in order to maximize treatment efficiency
at the farthest points from the radiation source.
At least one of the upstream and downstream faces of main body
104 includes one or more radiation source modules 148 mounted thereto.
Depending on the fluid to be treated, the number of modules 148
provided may be varied from a single upstream module 148 to two or
mare modules 148 across both the upstream and downstream faces of
main body 104.
Preferably, main body 104 further includes a radiation sensor 152
which extends into irradiation zone 144 and a fluid level sensor 156
which monitors the level of fluid in the inlet side of treatment zone 112.
As is known to those of skill in the art, if the level of fluid in the system
falls below fluid level sensor 156, an alarm or shutdown of the radiation
sources will occur, as appropriate. A standard fluid levelling gate 150
is also provided downstream of main body 104 to maintain a minimum
fluid level in treatment zone 112.
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,....
As best shown in Figures 4 and 5, each radiation source module
148 includes a radiation source support leg 160, a horizontal support and
guide member 164 (optional), a connector box 172 and one or more
radiation source assemblies 176 adjacent the lower extremity of support
leg 160. Each radiation source assembly 176 includes a high intensity
radiation source 180 which is mounted within a hollow sleeve 184 by
two annular inserts 188. Of course, it will be apparent to those of skill
in the art that in some circumstances radiation sources assemblies 176
will not require a sleeve and radiation source 180 may be placed directly
in the fluid to be treated.
Each sleeve 184 is closed at the end distal support leg 160 and is
hermetically joined to a mounting tube 192 connected to support leg
160. The hermetic seal between sleeve 184 and mounting tube 192 is
accomplished by inserting the open end of sleeve 184 into a mount 196
which is hermetically fastened to the end of mounting tube 192. A
rubber washer-type stopper 200 is provided at the base of mount 196 to
prevent sleeve 184 from breaking due to it directly contacting housing
196 as it is inserted. A pair of O-ring seals 204, 208 are placed about
the exterior of sleeve 184 with an annular spacer 206 between them.
After sleeve 184, O-ring seals 204, 208 and annular spacer 206
are inserted into mount 196, an annular threaded screw 212 is placed
about the exterior of sleeve 184 and is pressed into contact with m~unt
196. The threads on screw 212 engage complementary threads on the
interior of mount 196 and screw 212 is tightened to compress rubber
stopper 200 and O-ring seals 204 and 208, thus providing the desired
hermetic seal.
The opposite end of each mounting tube 192 is also threaded and
is mated to a screw mount 216 which is in turn welded to support leg
160. The connections between mounting tube 192 and screw mount 216
and between screw mount 216 and support leg 160 are also hermetic
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thus preventing the ingress of fluid into the hollow interior of mounting
tube 192 or support leg 160.
Each radiation source 180 is connected between a pair of
electrical supply conductors 220 which run from connector box 172 to
radiation source 180 through the inside of support leg 160 and mounting
tube 192.
As best shaven in Figures 4 and 5, a cleaning assembly 224 is
also included on each radiation source assembly 176 and mounting tube
192. Each cleaning assembly 224 comprises a cylindrical sleeve 228
which acts as a double-action cylinder. Cylindrical sleeve 228 includes
an annular seal 232, 234 at each end of the sleeve. Seal 232, which is
adjacent support leg 160, engages the exterior surface of mounting tube
192 while seal 234, which is distal support leg 160, engages the exterior
surface of radiation source assemblies 176.
The exterior of mount 196 includes a groove in which an O-ring
seal 236 is placed. O-ring seal 236 engages the inner surface of
cylindrical sleeve 228 and divides the interior of cylindrical sleeve 228
into two chambers 240 and 244. Chamber 240 is connected to conduit
248 and chamber 244 is connected to conduit 252. Each of conduits 248
and 252 run from connector box 172, through the interior of support leg
160 and through the interior of mounting tube 192, to mount 196 where
they connect to chambers 240 and 244, respectively. -
As will be readily understood by those of skill in the art, by
supplying pressurized hydraulic oil, air or any suitable fluid to chamber
240 through conduit 248, cylindrical sleeve 228 will be urged toward
support leg 160 and will force fluid out of chamber 244 and into conduit
252. Similarly, by supplying pressurized fluid to chamber 244 through
conduit 252, cylindrical sleeve 228 will be urged toward sleeve 184 and
will force fluid out of chamber 240 and into conduit 248.
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,.,..
Conduit 252 is connected to a supply of an appropriate cleaning
solution, such as an acidic solution, and conduit 248 is connected to a
supply of any suitable fluid, such as air. Thus, when it is desired to
clean the exterior of sleeve 184, pressurized cleaning solution is supplied
to chamber 244 while fluid is removed from chamber 240. Cylindrical
sleeve 228 is thus forced to an extended position distal from support leg
160 and, as cylindrical sleeve 228 moves to its extended position, seal
234 could also sweep loose foreign materials from sleeve 184.
When the cylindrical sleeve 228 is in its extended position, the
cleaning solution in chamber 244 is brought into contact with the
exterior of radiation assemblies 176, which forms the interior wall of
chamber 244, and the cleaning solution chemically decomposes and/or
removes the remaining foreign materials which are fouling radiation
assemblies 176. After a preselected cleaning period, fluid is forced into
chamber 240, the pressure on the cleaning solution is removed from
chamber 244 thus forcing cylindrical sleeve 228 to a retracted position
adjacent support leg 160. As cylindrical sleeve 228 is retracted, seal
234 again could sweep loosened foreign materials from the surface of
radiation assemblies 176.
As will be understood by those of skill in the art, the abave-
described cleaning assembly 224 may be operated on a regular rimed
interval, for example once a day or, where the quality of the fluid being
treated varies, in response to variations in the readings obtained from
radiation sensor 152.
Each radiation source module 148 can be mounted to main body
104 by horizontal support member 164 which has a predefined cross-
sectional shape and which is received in a complementary-shaped bore
256 in main body 104. The predefined shape is selected to allow easy
insertion of horizontal support member 164 into bore 256 while
preventing rotation of horizontal support member 164 within bore 256.
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As can been seen in Figures 3 and 4, the length of horizontal
support member 164 is selected such that horizontal support member 164
extends from support leg 160 to a greater extent than does radiation
source assembly 176. In this manner, radiation source assembly 176 is
maintained well clear of the inlet or outlet transition regions as the
radiation source module 148 is being installed. This arrangement
minimizes the possibility of damage occurring to the radiation source
assembly 176 from impacting it against other objects while installing
radiation source module 148 and this is especially true if fluid is flowing
through system 100. Due to the resulting required length of horizontal
supports 164, bores 256 are horizontally staggemd on opposite faces of
main body 104.
When horizontal support member 164 is fully seated within bore
256, electrical power connectors 264, cleaning solution connectors 268
and fluid connectors 272 on connection box 172 are brought into
engagement with complementary connectors on an enclosure 276. The
engagement of connectors 264 and 272 with the complementary
connectors on enclosure 276 also serves to maintain horizontal support
member 164 within bore 256. Enclosure 276 may comreniently contain
ballasts to supply electrical power for radiation sources 180 and pumps
and storage vessels (not Shawn) for cleaning fluid and pressurized fluid
for cleaning assemblies 224.
Recent improvements in radiation source technology have naw
made radiation sources of greater intensity available and devices which
are filamentless are available. In comparison, prior art UV lamps
employed in fluid treatment systems had rated outputs in the order of 1
watt per inch and were five feet in length.
As these greater intensity radiation sources emit more radiation,
fewer radiation sources are needed to treat a given amount of fluid. As
is known to those of skill in the art, the dosage of radiation received by
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:.
the fluid is the product of the radiation intensity and the exposure time.
The intensity of the radiation varies with the square of the distance the
radiation passes through, but the exposure time varies linearly with the
fluid flow velocity Accordingly, it is desired to maintain the fluid to
be treated as close as possible to the radiation sources. This requires
either many low intensity radiation sources arranged within a large
treatment area or fewer high intensity radiation sources arranged within
a smaller treatment area. For reasons of efficiency, minimizing expense
and for mitigating the above-mentioned requirement of accurately
controlling fluid level, the latter alternative has been adopted by the
present imrentor as described above. Irradiation zone 144 is designed
to present a closed cross-section to the fluid flow thereby ensuring that
the fluid to be treated passes within a predetermined maximum distance
of a minimum number of high intensity radiation sources 180. The flaw
rate of fluid through irradiation zone 144 can be increased so that an
acceptable rate of fluid treatment is maintained with a minimum number
of high intensity radiation sources.
Thus, the present system has been designed to minimize the size
of irradiation zone 144 while elevating the fluid flow velocity to obtain
the desired rate of treatment. Thus, the flow rate through irradiation
zone 144 is higher than in prior art treatment devices which are typically
designed to operate at flow rates of 2 feet per second or less: In
contrast, the present system may be operated at a flow rate through
irradiation zone 144 of up to 12 feet per second.
As is known to those of skill in the art, pressure head losses
through a fluid conduit are a function of the square of the fluid flaw
velocity Thus, high flow velocities result in increased head loss and
may result in unacceptable fluctuations in the fluid level in the treatment
system. Accordingly, the present system may be provided with inlets
and outlets having large cross-sections to minimize head losses and to
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facilitate insertion and removal of radiation source modules as will be
discussed below. The actual irradiation zone 144 is a relatively short
length of reduced cross-section and is connected to the inlets and outlets
by respective transition regions. In this manner, a desired relatively
high flow rate through the irradiation zone 144 may be accomplished
and hydraulic head losses minimized.
Other advantages provided by the present invention include
simplified maintenance, as the radiation source assemblies may be
cleaned of fouling materials in situ, and relatively easy removal of
radiation source modules for maintenance or radiation source
replacement. Further, the capability of in situ cleaning minimizes or
eliminates the requirement for otherwise redundant radiation sources to
be provided to replace those removed for cleaning and it is contemplated
that the elevated velocity of the fluid through the irradiation zone will
reduce the amount of fouling materials which adhere to the radiation
sources.
Another embodiment of a radiation source module 1488 and a
cleaning assembly 300 is shown in Figures 6 and 7 wherein like
components of the previous embodiment are identified with like
reference numerals. As most clearly shown in Figure 7, sleeve 184 is
hetlnetically sealed to mounting tube 192 at housing 196 in a manner
very similar to the embodiment shown in Figure 5. However, in-this
embodiment cleaning assembly 300 comprises a web 304 of cleaning
rings 308 and a pair of double-action cylinders 312,314. Each cleaning
ring 308 includes an annular chamber 316 adjacent the surface of sleeve
184 and cleaning rings 308 are swept over sleeves 184 by the movement
of cylinders 312,314 between retracted and extended positions.
As with the embodiment shown in Figure 4, conduits 320 and 324
run from connector box 172 (not shown) through support leg 160 to
cylinders 312 and 314 respectively. When fluid is supplied under
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pressure through conduit 320 to cylinder 312, the cylinder's piston rod
328 is forced out to its extended position. As will be understood by
those of skill in the art, as piston rod 328 is extended by the supply of
fluid to the chamber 332 on one side of the piston 336, fluid is forced
out of the chamber 340 on the second side of the piston 336 and passes
through connector link 344 to chamber 348 of cylinder 314 forcing its
piston rod 328 to also extend and the fluid in chamber 352 to be forced
into conduit 324.
In order to ensure that piston rods 328 travel synchronously,
cylinders 312 and 314 are designed such that the volume of fluid
displaced per unit of stroke of piston 336 in cylinder 312 is equal to the
volume of fluid received per unit of stroke of piston 336 in cylinder 314.
As will be understood by those of skill in the art, this is accomplished
by selecting appropriate diameters for each of the two cylinders or the
cylinder rods. As will be further understood by those of skill in the art,
an one way compensator valve 356 is employed at the end of the
extended stroke of the pistons 336 to further compensate for the any
difference in the total volume of fluid which may result between
chambers 332 and 352 and between chambers 348 and 340.
In a similar fashion, to retract piston rods 328, pressurized Huid
is supplied to conduit 324 and a second compensator valve 356 is
employed to compensate for the any difference in the total volume of
fluid which may result between chambers 332 and 352 and between
chambers 348 and 340 at the end of the retraction stroke.
It is contemplated that annular chambers 316 will be filled with
a predetermined quantity of suitable cleaning fluid which could be
changed at appropriate maintenance intervals, such as when servicing the
radiation sources. Alternatively, annular chambers 316 could be
supplied with cleaning solution via conduits run through the hollow
center of piston rods 328. Another alternative is to prrnride annular
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chambers 316 in a sealed configuration to contain cleaning fluid which
can be replaced when necessary. Further, the cleaning solution could
be circulated through hollow piston rods 328, chamber 332 and annular
chambers 316. By providing appropriate bafliing means (not shown)
within annular chambers 316, the cleaning fluid could enter through the
lowermost hollow piston rod 328, circulate through cleaning rings 308
and exit through uppermost hollow piston rod 328.
While Figures 4, 5 and 6 illustrate specific embodiments of the
aspect of the invention relating to cleaning apparatus for a radiation
source assembly, other designs will be apparent to those of skill in the
art without departing from the spirit of the invention.
For example, it is possible to employ a single, double-action
cylinder in combination with a hollow cylinder rod that is very rigidly
mounted through its cylinder rods on a plurality (e.g. 2 or 4) of cleaning
rings 308. Further, it is possible to pump cleaning fluid (e.g. water)
through hollow piston rods toward and into annular chambers 316 while
moving the cylinder back and forth. If annular chambers 316 were
outfitted with suitable spray nozzles or the like, it would possible to
apply a spray or jet stream across the surface of the irradiation chamber
thereby facilitating cleaning of sleeve 184 of the radiation source.
Another design modification involves prefilling annular chambers
316 with a suitable cleaning fluid and modifying the chambers to provide
a closed wiping assembly This would allow for the use of various
translation means to move the annular chambers 316 back and forth aver
sleeve 184 of the radiation source. For example, it is possible to utilize
a double-acting, single cylinder that merely translates annular chambers
316 back and forth over sleeve 184 of radiation source. Of course it
will be apparent to those of skill in the art that the annular chambers
should be mounted rigidly to the translation means to avoid jamming of
the entire assembly resulting in damage to sleeve 184.
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As will be further apparent to those skilled in the art, in the
embodiments described above, it is possible to reverse relative
movement between the radiation source and the cleaning mechanism.
Thus, the cleaning mechanism could be mounted rigidly with the
treatment zone in the p~sent or any other system, and the radiation
source would be translated back and forth with respect thereto.
Another preferred embodiment of the present irnendon is shown
in Figure 8. In this embodiment a treatment system 400 includes a main
body 404 with a lower surface which, with a base wall 406, defines a
treatment zone 408. Treatment zone 408 comprises an inlet transition
region 412, a first irradiation zone 416, an intermediate zone 420, a
second irradiation zone 424 and a tapered outlet zone 426. As is
apparent from the Figure, outlet zone 426 is lower than inlet zone 412
to provide some additional hydraulic head to the fluid being treated to
offset that lost as the fluid flows through the treatment system. It will
be apparent to those of skill in the art that, in this configuration, the
requirement for level controlling gates and the like is removed as the
treatment zone 408 also performs this function through the positioning
of its inlet and outlet.
Main body 404 could also include bores 430 to receive vertical
support members 434 of radiation source modules 438. Radiation
source modules 438 are similar to the above described radiation source
modules 148 but are configured for vertical positioning of the radiation
source assemblies 442. Radiation source assemblies 442 include sleeves
446 which are connected to mount stubs 450. Of course, as mentioned
above, it will be understood that in some circumstances the radiation
source assemblies 442 will not require a sleeve and may instead be
placed directly in the fluid to be treated.
As mount stubs 450 are located above the maximum level of fluid
in treatment system 400, the connection to sleeves 446 need not be
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hermetically sealed and may be accomplished in any comrenient fashion.
Of course, as the connection point between sleeves and mount stubs 450
is above the level of fluid within the system, the interior of sleeves 446
will not be exposed to fluid .
Mount stubs 450 are in turn connected to support arms 454 which
are attached to vertical support members 434. Radiation sources 458 are
located within sleeves 446 and are connected between electrical supply
lines (not shown) which are run from connectors 462, through hollow
support arms 454 and mount stubs 450 and into sleeve 446. Connectors
462 connect with complementary connectors on enclosure 466 which
may include a suitable power supply and/or control means for proper
operation of the radiation sources 180 and cleaning supply systems, if
installed.
In this embodiment, service of radiation source modules 438 is
accomplished by lifting the radiation source modules 438 vertically to
remove them from the fluid flow. While not illustrated in Figure 8, it
is contemplated that in some circumstances the cleaning assemblies
described above will be desired and it will be apparent to those of skill
in the art that either of the cleaning assembly embodiments described
herein, or their equivalents, can be favourably employed with this
embodiment of the present invention. Alternatively, it is contemplated
that when the sleeves 446 require cleaning, a radiation source module
may simply be removed by lifting it vertically.
As described above, fluid treatment systems typically include a
radiation sensor 152 to monitor the intensity of radiation within an
irradiation zone. These sensors include a radiation transmissive window
behind which the sensor proper is mounted and the window is inserted
into the fluid flow. Of course, as with radiation source assemblies 176
(442), this window becomes fouled over time.
CA 02239925 1998-08-10
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Figure 9 illustrates radiation sensor assembly 500 in accordance
with another aspect of the present invention. Sensor assembly 500
includes a cylindrical body 502 in which a bore 504 is formed. A
radiation sensor element 508 is located at the interior wall of bore 504
adjacent to a rod 512 which is radiation transmissive and which extends
from a front face plate 514 attached to body 502. Sensor element 508
is hermetically sealed from fluid by O-rings 516 which are adjacent
sensor element 508 and by O-ring 520 which surrounds rod 512 at the
connection point between front face plate 514 and body 502. The
electrical leads 524 from sensor element 508 exit the rear of body 502
through bore 528.
Since the exposed end of rod 512 will become fouled over time,
face plate 514 also includes a cleaning jet 532. Cleaning jet 532 is
hermetically connected to bore 536 with O-ring 538, through body 502,
which is in turn connected to a supply of pressurized cleaning fluid (not
shown) such as an acidic solution, water or air.
When pressurized cleaning fluid is pumped applied to bore 536,
cleaning jet 532 directs the cleaning fluid onto the exposed surfaces of
rod 512 to remove fouling materials. To prevent damage to cleaning jet
532, rod 512 and to streamline fluid flow, a shroud is also provided.
'- Radiation sensor assembly 500 may be mounted in a sleeve
connected to the treatment zone of a fluid treatment system as wild be
apparent to those of skill in the art. Radiation sensor assembly 500 can
be maintained within such a sleeve by a set screw (not shown) which is
received in keyway 540. Of course, as is known by those of skill in the
art, for accurate results it is desired that rod 512 be orientated
substantially perpendicular to the radiation sources 180 being monitored.
It is contemplated that in normal use, radiation sensor assembly
500 will be cleaned by supplying a predetermined amount of cleaning
solution or water at predefined time intervals, to cleaning jet 532.
CA 02239925 1998-08-10 ".
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It should be understoad 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 scope of the invention as defined by the attached claims.
