Note: Descriptions are shown in the official language in which they were submitted.
CA 02623601 2008-03-27
Field of the Invention
[0001] The present invention relates generally to traps for biting insects,
mainly blood
sucking insects. More particularly, the present invention maintains an optimum
breeding pool for
insects, specifically the for family Culicidae (mosquito), but not restricted
to it.
CA 02623601 2008-03-27
Background of the Invention
[0002] It is well documented that biting insects, specifically Culicidae
(mosquito), are a
vector of many diseases throughout the world. Extensive efforts have been
carried out worldwide to
diminish/eliminate mosquitoes, as they are vectors for diseases like malaria
and dengue fever, as
well as other biting insects, from areas frequented by humans or their
domesticated animals, using
many different methods and technologies.
[0003] For the sake of this discussion, the description will be primarily
limited to the control
of mosquitoes, but this invention is not limited only to the family Culicidae.
Mosquitoes are one of
the most widespread biting insects, and the described system has been tested
and proven effective on
mosquitoes by the authors. However, the functionality of this invention would
apply to any other
insect that deposits its eggs in this device, and will similarly be
controlled. Further research is
required to isolate suitable attractants for other insects, which is beyond
the scope of this invention.
[0004] There are many different kinds of systems to deal with adult insects,
from adult traps,
nets, topical repellants and others. However, these techniques do not have an
impact on the life
cycle of the insects, and are therefore not a consideration with respect to
this invention.
[0005] The only way to truly decrease the number of mosquitoes that are
available to bite
humans is to decrease the local population. This can be done by interrupting
the life cycle of the
insect in its aquatic stages. Each gravid (pregnant) mosquito, for example,
can lay as many as 200-
300 eggs, and this can exponentially increase the mosquito population in a
very short time.
However, if one is able to consistently stop the reproductive cycle before the
young reach maturity,
the local population of mosquitoes can be dramatically decreased in the
treated area.
[0006] Research has shown that mosquitoes will only travel approximately 250m
in the
search for food and/or breeding location, and, therefore, if you decrease the
local population, there
will be considerably fewer mosquitoes in a given area. When the local
population is depressed for
an entire season, there will be fewer mosquitoes available to lay eggs that
will over winter
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CA 02623601 2008-03-27
(assuming the trap is in a colder climate), which will in turn assure a
smaller starting population for
the next season. Over time, the same effect can be attained even in tropical
climates.
[0007] There has been extensive use of various pesticides to accomplish this,
both air and
water borne, but these are extremely problematic. Serious long lasting
consequences to both the
environment and human health have resulted (e.g DDT, malathion) from the use
of such pesticides.
Included in this grouping are larvicides and adulticides used by many known
inventions, for
example U.S. Patent No. 6389740 (Perich et al) and similar. Any use of
pesticides are not desired
for environmental reasons, and these chemicals are known to repel insects,
thereby decreasing the
effectiveness of the device. Furtherniore, there is evidence that some species
of mosquito are
beginning to become resistant to these chemicals, and it is therefore of
paramount importance to
ensure that any method will not be subject to the possibility of resistance.
[0008] Many biting insects, including mosquitoes, require stagnant pools of
water in order to
lay their eggs. Traps to accomplish this are known as ovitraps. In order
improve the effectiveness
of an ovitrap, the contained water must be made more appealing to the mosquito
than other breeding
locations in the area. An attractant can be added to the water to make it
somewhat preferred. An
example of such a device can be seen in U.S. Patent No. 3997999, (Evans),
using a styrofoam
coffee cup, water, and an attractant. There are many different types of
attractants that can be used to
accomplish this, which are too numerous to mention. The described invention
can use any of these,
but they are not required for the trap to function. The water used must also
be free of fish (i.e. not
from a source having fish) and other predators, chlorine (as found in urban
tap water), pesticides,
petroleum products and surfactants, as these will signal to the insect an
unsuitable breeding location.
[0009] Once a mosquito arrives at the breeding pool, and lays its eggs, it
leaves the trap.
After a few hours (varying by species), the eggs hatch, releasing the larvae
into the solution to grow.
After the eggs are laid, a chemical cue is released that signals to other
mosquitoes that location is a
successful breeding site, which in turn attracts other mosquitoes to lay their
eggs. Most of this
chemical cue is thought to be released after hatching. This chemical cue is a
very effective
attractant, and acts synergistically with any attractant already in solution.
Over time, if this
chemical cue is preserved, the trap will attract mosquitoes from a larger
area, with greater
effectiveness over natural locations.
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CA 02623601 2008-03-27
[0010] The invention described herein capitalizes on this fact, by ensuring
the retention of
this chemical cue, and, over time, concentrating it as more mosquitoes lay
their eggs. In previous
years, variants of the described device were emplaced by the authors in
various locations known to
have considerable mosquito populations, and were monitored to determine their
effectiveness.
Through the season, the desirable chemicals were maintained, and the
effectiveness was greatly
increased. These locations were determined to be preferentially used over both
controls and natural
locations, and had a significant impact on the local mosquito population. No
known prior art
preserves a clean solution, such that it might be reused to attract more
mosquitoes.
[0011] A discovery in the aforementioned testing process was that various
biological
contaminants were introduced into the solution naturally, among them dead
insects, debris (sticks
and leaves), as well as algae and a fermented slime from the organics that are
required in the
solution by the insect. These contaminants are problematic, most notably the
slime. Over time, it
builds up on the surface of the solution, and can completely stop the
deposition of eggs, as the
mosquitoes cannot get to the water. The contaminants also result in a
substantial smell. Filtering
the solution is therefore of paramount importance to keep these contaminants
from building up, so
that the solution will remain in its optimum state.
[0012] It should be noted that a screen or mesh is not sufficient to filter
the solution. Given
the diminutive size of the eggs and the first and second instars (mosquito
larvae), which can be less
than 1/10 mm in size. A very fine screen is required, much finer than a normal
window screen, in
order to successfully remove all larvae and pupae from the solution, and any
screens with such a
small aperture are either so fragile that they cannot be used for this purpose
because they would
become punctured too easily, or would clog very quickly in the case of metal
meshes. This is of
special importance, because the vast majority of the prior art, for example
U.S. Patent No.
20070074447 (Kalogroulis) and similar use screens or mesh to remove eggs,
larvae and pupae from
the solution. US Patent No. 6990768B1 (Boston) suggests the use of a 'filter
belt', however, this is
described as "a woven metal mesh that has sufficiently small openings so that
mosquito eggs and
larvae are retained". From the description, this is a screen. Due to the
aforementioned additional
contaminants, these systems would either become useless, or potentially make
the problem worse
since there is no failure mode to contain the resultant adult mosquitoes. In
addition, the trap
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CA 02623601 2008-03-27
described in US Patent No. 6990768B 1(Boston) would more than likely result in
larvae, pupae and
contaminants making it past this step, as they would stick to the 'filter
belt' until washed off by
following cycles, and put into the reservoir.
[0013] It is also necessary to completely drain the solution through the
filter at once, to
ensure nothing is missed; larvae and pupae can swim, and can potentially avoid
capture if there
locations where they can survive. Some known inventions, for example, US
Patent No.
2006/0086037A1 (Roberts) and U.S. Patent No. 6886293 (Forehand) and similar
entrust that the
larvae and pupae will find their way into the part of the device that will
attempt to remove or retain
them, which is virtually impossible to ensure. Furthermore, in the case of
system malfunction,
systems such as US Patent No. 2006/0086037A 1(Roberts) will leave an ideal
breeding pool with no
method of preventing release of adult insects, thereby making the problem
worse.
[0014] Once filtered, the solution must be returned to the ovitrap. As
mentioned, the added
chemical cues released by the eggs laid by the insects will make the trap more
effective. This can be
done by using a pump, manually, or any other method.
[0015] A pump is preferred, because this allows the possibility of keeping the
ovitrap full to
an optimum level without human interaction; mosquitoes are most prevalent when
the ambient
temperature is above 20 degrees Celsius, and therefore evaporation is an
ongoing concern. By
keeping a larger volume of solution in the container below the filter,
additional solution can be
added to the ovitrap as is needed. The volume of solution below the filter
should be larger than that
of the ovitrap and protected from direct sunlight to limit evaporation.
Furthermore, by having a
large volume of clean solution, it is easier to ensure that the chemical cues
are retained in solution,
even through extended dry spells.
[0016] Automation of this method is preferred because the life cycle of the
mosquito can be
very short. In ideal conditions, depending on species, mosquitoes can go from
egg to adult in as
little as 4 (four) days. It is therefore necessary to filter the solution more
regularly, ideally every
two or three days. However, with various usage scenarios (such as at a
recreational properties,
remote locations, limited human resources, etc.), people may not be available
to cycle the system as
regularly as is required to both maintain the effectiveness of the solution,
and prevent new
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CA 02623601 2008-03-27
mosquitoes from leaving the trap. It is therefore desirable that any system be
able to operate
unattended for a minimum of 28 days. This requirement further accentuates the
problems in the
known art, since they would require regular attendance to keep them
functioning.
[0016] When automating the process, the slime becomes the most important
factor to
consider. Failure to address the slime and resulting blockage will either
greatly reduce the
effectiveness of the trap, if not stop it from functioning altogether. If the
filter does not function
properly, it would either do nothing at all, or make the mosquito problem much
worse. In the scope
of this invention, it should be noted that any type of filter designed to work
with aqueous media,
remove particles as small as newly hatched larvae, and sufficient surface area
and height to continue
to function over several cycles can be used. An example of such a filter would
be the type used in a
wet/dry vacuum cleaner.
[0017] Due to the automation requirement, there must be electrical elements
such as a pump
and a motorized valve, as well as a control system with a timer to start the
process. It should be
noted, however, that these components must be at a minimum, for simplicity and
cost. Those
components that are included should be robust and resistant to the
environment, including the slime.
Elements of the apparatus must also be in place to monitor water levels, and,
when water is scarce
(due to a lack of rainwater or human intervention), the apparatus must be able
to ensure that the
apparatus enters into a default state that will make sure that no stagnant
water is left unfiltered and
available to allow adult mosquitoes to hatch. It should also enter this state
in case of any problem
that might prevent normal operation.
[0018] The automation of the system can be done in several ways using
different
components, using simple logic switches, a printed circuit board, or
microprocessor, but it should
always be possible to change components to allow for manual operation of all
aspects. This will
allow the apparatus to be manufactured cheaply to be used in the developing
world, where a fully
automatic (and therefore more expensive) system is financially unacceptable.
CA 02623601 2008-03-27
Summary of the Invention
[0019] The foregoing needs are met by the details of the present invention,
wherein a
method and apparatus is provided that maintains an ideal breeding pool for
mosquitoes and other
insects, while as an intended side-benefit removes the aquatic young from the
solution, thereby
interrupting the insect life cycle, comprising of a minimum of; a primary
container to store a
solution, known as an ovitrap; an valve, manual or automatic, to release the
solution; a filtration unit
to receive the released solution and to filter it, being sufficient volume to
accommodate the entire
contents of the ovitrap; a secondary container to receive the filtered
solution. To further automate
the process, additional components are added, comprising but not limited to; a
pump to return the
filtered solution to the ovitrap; a float switch to activate the pump when the
fluid level in the ovitrap
is decreased; a tertiary tank to separately store supplementary water (either
rain, well or tap); a float
valve to provide water from the tertiary tank when the fluid level in the
secondary container drops
below a pre-determined level; a roof with trough to partially shade the
primary container and hold
solar panels, and to collect rain water into the tertiary container; a power
supply, either AC or DC; a
float valve in the secondary container to initiate a fail-safe mode; a control
unit to ensure proper
sequencing of the aforementioned parts.
[0020] In accordance with one aspect of the present invention, a method of
interrupting
insect life cycles, comprising of the steps of attracting mosquitoes to lay
eggs; allowing some of the
eggs to hatch and release a chemical cues; passing the solution with the
aquatic young, and other
contaminants through a filter such that contaminants are retained; reusing the
filtered solution to
maintain and concentrate the natural chemical cues.
[0021] In accordance with another aspect of the present invention provides an
apparatus to
collect mosquito eggs in solution; allow some of the eggs to hatch; to drain
the solution through a
filter periodically; return the filtered solution so that more mosquito eggs
may be collected; having a
tertiary source of water to keep water levels ideal.
[0022] In accordance with another aspect of the present invention provides
that the filter can
withstand an aqueous medium, be able to retain the smallest biological
contaminants in solution, of
sufficient volume to contain the volume of the ovitrap, sufficient surface
area to provide long
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CA 02623601 2008-03-27
duration functionality, and sufficient height to allow a percentage of the
filter to remain pristine
through early cycles of filtration such that there will be clean filter
surface for later filtration cycles.
[0023] In accordance with another aspect of the present invention provides a
simple and
modular design of both overall structure, functional elements and a minimum of
parts requiring
electricity such that the apparatus is easy to construct, inexpensive,
expandable as desired,
functional unattended for long durations, and easily maintained.
[0024] There has thus been outlined in broad form certain embodiments of the
invention in
order that the detailed description herein may be better understood, and in
order that the present
contribution to the state of the art may be better appreciated. There are
other embodiments of the
invention that will be described below, and will form the subject matter of
the claims appended
hereto.
[0025] It must be understood that the invention is not limited in its
application to the specific
details of construction and components as outlined in the following
description and illustrations.
The invention can be embodied in many different ways, as can the method being
practiced. It is also
understood that the phraseology and terminology used herein are for the
purpose of description and
are not intended to be limiting.
[0026] Those skilled in the art will appreciate that the concepts on which
this disclosure is
based may be utilized as a basis for the design and construction of other
constructs, methods and
systems for carrying out the purposes of the present invention. It is
important that the claims be
regarded as including such equivalencies so long as they do not depart from
the spirit and scope of
the present invention.
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Brief Description of the Drawings
[0027] The invention will be better understood with reference to the drawings
in which;
[0028] Figure 1 is a block/flow diagram describing the method of the
invention;
[0029] Figure 2 is an exploded view of the rectangular preferred embodiment;
[0030] Figure 3 is a cross-sectional view of the rectangular preferred
embodiment;
[0031] Figure 4 is an exploded view of the cylindrical preferred embodiment;
[0032] Figure 5 is a cross-sectional view of the cylindrical preferred
embodiment;
[0033] Figure 6 is a close up view of the filter section
[0034] Figure 7 is a cross-sectional view of the filter section, showing
solution flow through
the filter during cycle.
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Detailed Description of the drawings
[0035] Reference is first made to Figure 1 to describe the method used by the
apparatus. It
should be understood that the parts outlined in figure 1 may be interchanged
with any other parts to
accomplish the same task. As can be seen in Fig. 1, there is a primary
container 20, known
henceforth as the ovitrap, holds a liquid, protected by a roof 45. The liquid
is infused with an
attractant material, contained in a cartridge 43 separated from the main body
of the liquid by a
screen 44 to keep large organic particles from entering the liquid from the
cartridge, but otherwise
allowing water and the chemical attractants released to move freely.
Mosquitoes are attracted to the
liquid and attractant to deposit their eggs in the ovitrap 20.
[0036] For the purposes hereof, any reference to "solution" shall be
understood to be the
combination of water, added attractants, and the natural chemical cues
released by hatched eggs.
Furthermore, "contaminants" shall be understood to be any non-soluble
materials that may be
contained in the solution, such as foreign material such as leaves or sticks,
biological material such
as the by-products of fermentation or algae or other microbes, live and dead
insects that are either
adult or immature (i.e., eggs, larvae or pupae), and any other non-soluble
materials that are brought
into the solution over time.
[0037] A control system 33, which includes a timer, is programmed to initiate
an operation
cycle in a timely manner, giving some of the mosquito eggs in the ovitrap 20
sufficient time to
hatch, and release their chemical cues into the solution. When the control
circuit 33 indicates a start,
it sends a signal to the main valve 22 to open. The main valve 22 opens for
long enough to drain the
ovitrap, either by a pre-determined time programmed in the control circuit 33
or an optional float
switch in pipe 21 (not illustrated). It should be understood that the control
system 33 can also have
an external thermometer and/or light sensor to adjust the timing of the cycle
depending on the
ambient temperature, and day/night cycles.
[0038] It should be noted that for the purposes of this invention that pipes
21, 23, 25, 36, and
38 are not expressly required for this method to function, should it be
practical or desirable to
connect either the main valve 22 or float valve 37 in such a way that they are
directly connected to
the those parts that are upstream and downstream.
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CA 02623601 2008-03-27
[0039] Once the solution and contaminants in the ovitrap 20 begin to flow from
the opening
of the main valve 22, float switch 30 opens the circuit to the pump 28 via
connection 31. The pump
turns on, and starts to move the solution in the secondary container,
henceforth known as filtered
solution tank 26, via pipe 27 into the top of the ovitrap via pipe 29, acting
to rinse the ovitrap. The
end of pipe 29 can be positioned to cause a vortex in the ovitrap to improve
the cleaning of the
ovitrap 20, and may have a nozzle to create a higher pressure spray if
desirable. Pipe 21, 23 and
main valve 22 must be of sufficient diameter to ensure that the ovitrap 20
drains faster than the
pump 28 can fill it, and to ensure that objects do not bind in the pipe.
[0040] The solution and contaminants in ovitrap 20 drain through the open main
valve 22
through pipe 23 into a filter 24. This filter must be a fme filter to ensure
that all contaminants are
retained in the filter, while the solution is allowed to drain through pipe 25
into the filtered solution
container. The volume of the filter 24 must be larger than the ovitrap 20, and
said volume must
contain the solution and contaminants completely within the filter so that no
contaminants may by-
pass the filter. Optional screens 47 may be added to provide airflow around
the filter 24 to properly
dry, thereby killing any aquatic life retained.
[0041] It should be understood that he filter must be strong enough to resist
puncture by
sharp objects likely to be in the ovitrap, fine enough to retain all
contaminants, and able to function
repeatedly wet, have a plurality of surfaces to inhibit clogging, of
sufficient volume to accommodate
the entire volume of the ovitrap, high enough to be effective through multiple
cycles, and can be
either rigid or flexible.
[0042] There must be sufficient solution in the filtered solution container
26, which contains
the solution, to fill the ovitrap 20 and retain a pre-determined minimum of
water in the filtered
solution container 26. Filtered solution container 26 should have limited
access to the atmosphere
outside the apparatus in order to limit evaporation, while still allowing some
of the attractants and
chemical cues to be released.
[0043] The tertiary container, henceforth known as the fresh water tank 35, is
provided to
top up the filtered solution container 26 through pipes 36 and 38 through
float valve 37. Float valve
CA 02623601 2008-03-27
37 monitors the solution level in the filtered solution container 26 through a
float 39. Rain water
that falls on the roof 45 covering the ovitrap 20 can be collected through a
pipe 46 into the fresh
water container 35 to ensure proper long-term functionality of the apparatus.
In the case of
excessive rain, an overflow outlet should be included. The fresh water
container 35 should not
allow contaminants from entering, using screens, check valves, or other means.
[0044] Float Switch 49 has a float 48 in the filtered solution container 26
that is activated
when the solution level in the filtered solution container 26 drops below a
minimum level, at which
point it sends a signal through connection 50 to the control unit 33, which
then opens main valve 22,
and enters a hibernation state as a failsafe mode.
[0045] Power 34 can be either a battery, or a battery and/or inverter and plug
to a secondary
power source, either grid, solar or generator. Power is delivered to the
control circuit 33, pump 28,
main valve 22 through the control circuit, and float switch 30.
[0046] Figures 2 and 3 demonstrate a rectangular preferred embodiment, whereby
the
overall shape of the invention is rectangular; it is understood that this
embodiment can be created
using off-the-shelf plastic bins, wood and rubber, custom molded plastic, or
other materials, and that
the body 248 can be separate components or as a single molded part. The
overall size of the system
can be variable, however, it is preferred that the total volume contained in
the ovitrap 220 is 5 litres
or more.
[0047] Figures 4 and 5 demonstrate a cylindrical preferred embodiment, whereby
the overall
shape of the invention is cylindrical; it is understood that this embodiment
can be created using off-
the-shelf plastic bins, wood and rubber, custom molded plastic, or other
materials, and that the body
248 can be separate components or as a single molded part. The overall size of
the system can be
variable, it is preferred that the total volume contained in the ovitrap 220
is 5 litres or more.
[0048] It is also understood that the filter 224 shown in figures 2, 3, 4 and
5 is intended to
describe a general filter. This filter must be able to handle an aqueous
medium, have a plurality of
surfaces so that it is not easily clogged, restrict particles smaller than
newly hatched insect larvae, be
16
CA 02623601 2008-03-27
of sufficient internal volume to retain the entire contents of the ovitrap
220, and be high enough that
it can operate effectively through multiple cycles and the buildup of
contaminants.
[0049] The preferred embodiments shown in figures 2,3,4,and 5 represent two
possible
convenient apparatuses for use in all locations. The legs 250 (on the
rectangular preferred
embodiment), roof 245, solar panel 247, and fresh water container 235 can be
detached and placed
in the volumes of the ovitrap 220 or filtered solution tank 226 for easy
stacking and transportation of
the unit.
[0050] The preferred embodiments depicted in figures 2, 3, 4, and 5 are
created in a modular
fashion, where support components such as the filter 224, pump 228, battery
234 and control system
233 are placed on trays 257, 261 and 262 such that the components can easily
accessed for
maintenance, or completely changed to different components. Furthermore,
mounting pins 263 are
provided to add components to the unit, such as a weather station, GPS
tracking, cell/radio
communications, etc.
[0051] Once the control unit 233 begins a cycle, the solution and contaminants
252, will
pass through the main valve 222, and enter into the volume above the filter
265, and come to the
filter itself 224, where the contaminants will be held, and the solution will
pass into the filtered
solution container 226, and become part of the filtered solution 251. As soon
as the main valve 222
opens, the water level will drop below the minimum ovitrap 220 water level
258, and the float
switch 230 will signal to the pump 228 to turn on, sending solution up pipe
229, to be released into
the ovitrap 220 through a nozzle 259. Should the level of solution 251 in the
filtered solution
container 226 drop below a minimum level 260, a float valve 237 will open,
releasing the water 253
from the fresh water container 235 to top up the filtered solution container
226. A screened opening
264 is provided to help keep the filter dry.
[0052] A roof 245 is provided with an optional solar panel 247 to charge the
battery 234.
Rain water that falls on the roof 245 is collected in a trough 249, and drains
into the fresh water
container 235 via pipe 246. A small screen 254 is placed on the upstream side
of pipe 246, in order
to keep contaminants from accessing the fresh water container 235. In the case
of excessive rainfall,
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CA 02623601 2008-03-27
a screened high water outlet 255 is provided to keep water from overflowing
the top of the fresh
water container 235.
[0053] Holes 256 are provided at ground level in order to be able to stabilize
the unit, via
spikes, bolts or otherwise, to prevent accidental tipping by humans or
animals.
[0054] Figure 6 shows a close up view of the filter unit, whereby the filter
301 sits on a tray
306 with holes punched 310 through the circumference to allow water to pass,
and a tray 307 to
support the unit.
[0055] The solution and contaminants 304 leave the valve 222 (figures 3 and
5), and flow
into the filter 301, whereby the level of the solution reaches a maximum point
of 309 when the filter
is clean. The solution passes through the filter 301, and drips down 308 to
the filtered solution tank
226 (figures 2,3, and 5). After each cycle, the solution completely drains
from the filter 301, and the
contaminants 302 are retained in the filter, sitting on the sealed bottom 305,
and dry, killing all the
eggs, larvae, and pupae. At the next cycle, the new solution and contaminants
304 are released atop
the old contaminants 302, and slowly build up the filter over time. After a
pre-determined number
of cycles, the filter must be changed or cleaned.
18
