Note: Descriptions are shown in the official language in which they were submitted.
SPECIFICATION ~27~29
This invention relates to insect traps and, more particularity, to traps for
monitoring or controlling flying insects such as house flies.
Insect traps which use light to attract flying insects have hitherto a) pulled the
insects into a container with suction, a suction trap, or b) blown them with an
undirected air stream into a sticky container or pan of liquid, a blower trap.
Present trapping systems which use light to attract flying insects and utilize
moving air to capture the insects are inefficient and most are ineffective for
capturing fast flying insects. A further disadvantage of the known traps is that
none is adapted to make use of a calibrated air flow relatively unaffected by
movements of air in the environment to dispense compounds which will excite or
attract flying insects. Many attract ants, in particular pheromones, must be
released at critical rates.
One such trap pulls the insects into a container with suction, a suction trap. The
air flow on the suction side of the fan is drawn from a hemispherical volume, or if
a lid is present from a cylindrical space at some distance from the fan. The flow
of air is therefore slower than the air flow on the output side, so that insects must
fly close to the trap before encountering a suction sufficient to cause their
capture. Fast flying insects such as bees and flies can escape from this airflow.
another such trap blows flying insects with an undirected air stream into a sticky
container or pan of liquid, a blower trap. The air flow of such a trap is undirected
and many insects may escape by being blown past the collecting device of a
blower trap.
It is therefore an object of the present invention to provide a trap in which air is
blown over an airfoil shape, concentrating the flow into a porous container.
A further object of this invention is the provision of a trap which uses the airfoil
effect to produce a negative pressure around the light to capture flying insects
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and force them into a stronger air flow which prevents their escape once
attracted.
A still further object of this invention is the provision of a trap which makes use
of a known and constant air flow through the porous container to dispense
compounds which will excite or attract flying insects.
The present invention makes use of the aerodynamic principle of the airfoil to
direct a volume of air blown from a venturi fan (with a rated output of 100 cubic
feet or more per minute) into a device for collecting insects.
The airfoil nature of the shape of a standard incandescent light bulb causes the air
from a fan mounted directly above it to travel in a directed stream, so that all of
the air from the fan enters the collecting device. A transparent cover with a
similar airfoil shape could be used with any other light source to create a directed
stream of air. The air travels over the light bulb at a velocity of about 30 km per
hour malting it impossible for fast flying insects to escape.
With this arrangement all the air flowing through the fan blows into the collecting
device at a known rate and it is therefore possible to dispense accurately known
amounts of an insect attrac$ant or extenuate from a suitable container within the
air stream.
Prototype, experimental traps, were developed which eliminated the
disadvantages of known traps. Their efficacy was evaluated in comparison to
other light traps in an egg production barn with a floor area of 1,000 my and a
population of about 850,000 adult flies. Traps placed in a row, 10 m apart, caught
a mean of 3 95 flies per trap each day. When traps were placed near
accumulations of flies on the roof, a mean of 2684 flies per trap per day were
caught. Addition of muscular (Z-9 tricosene), an insect attract ant, increased
catches by 23%. By comparison, the most effective commercial trap tested (Fly-
Watcher, Postulate Lancaster, PA, USA) collected a maximum of 320 flies per
day over a three day period, although the mean catch over 42 days was only 29
flies per day. These traps were mounted on the walls inside the barn at the same
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height as the experimental traps The Postulate traps rapidly became clogged
with dust in the chicken barn.
No house flies were seen to escape from the air flow when they flew within the
diameter of the collecting device of the experimental trap, whereas they did
escape from weaker suction traps or from the undirected air flow used in blower
traps.
Accordingly, the present invention provides a trap for use in trapping flying
insects, said trap utilizing light radiation in the visible and the adjacent
ultraviolet and infrared spectral regions, such as that emitted by incandescent or
fluorescent lamps. The insects are pulled into the air stream by the negative
pressure created by the airfoil shape that completely surrounds the light source
and are forced into the trap by the high speed air stream. Insects are collected in
a porous container, which can also dispense accurate quantities of an extenuate or
attract ant substance such as muscular (Z-9 tricosene), a pheromone for house
flies.
In drawings which illustrate embodiments of the present invention,
Figure 1 is a side elevation view of the insect trap of this
invention, shown partly in section;
:
Figure 2 is a cross-sectional view of the insect trap at the
level of the venturi fan;
Figure 3 is a cross-sectional view of the insect trap at the base
of the open cylinder;
Figure 4 is a diagrammatic illustration of the directed air
stream and suction created by the trap, and the disposition of the a~tractant or
extenuate for increased effectiveness.
Figure 5 is a diagrammatic representation of the flight path of
a flying insect being captured by the trap.
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~;~27~29 --
Referring now in detail to the accompanying drawings, the trap shown generally at
10 in Figure has a venturi fan 12, shown more clearly in Figure 2, with a
synchronous motor which may be protected by a cover 14 fitted with a centrally
disposed eyelet 16 to attach the trap to the ceiling of a building or other suitable
device, and metal terminals 18 to attach an electrical cable 20.
The fan blows air over an airfoil-shaped lamp 22 which, in this embodiment, is a
domestic incandescent lamp. As shown more clearly in Figure 3, the lamp 22 is
screwed into a base 24 which provides the electrical power to illuminate the lamp
from the terminals 18, by way of a pair of insulated wires 26. Electrical power for
the venturi fan is also provided by a pair of insulated wires forming part of the
same circuit. The base of the lamp 24 is attached to a crisps 28, which
serves to position the lamp 22 directly beneath the venturi fan 12. The
crisps 28 is attached to an open cylinder 30, which is suspended from the
venturi fan 12 by two or more dependent legs 32 . The crisps 2 8 also serves to
support devices such as illustrated in 34, which contain insect attract ants or
extenuates. Attached to the open cylinder 30, and suspended beneath it is the
porous collecting device 36. In this embodiment the device is a bag constructed
from nylon mesh, but in other embodiments, different materials with mesh or
holes small enough to retain the desired insects and yet allow air flow at the rated
output of the fan could be used. The collecting device 36, is held around the
cylinder 30, with a lace or elastic band 38, but in another embodiment it could be
attached in a different manner. For example, the collecting device comprising a
second cylinder, slightly larger than the first 30, and having a bayonet-type mount
would allow the collecting device to be changed more readily.
The movement and direction of the air flow, which is the essence of this
invention, is shown in Figure 4. The trap 10 draws incoming air 40 from around
the trap. Incoming air 40 is forced by the venturi fan 12 over the lamp 22 forming
a directed air stream 42. The aerodynamic shape of the lamp 22 induces a
quickening of air flow within the directed air stream thus producing a negative
pressure 44 as a result of the airfoil effect. The directed air 42 is blown into the
collection device 36, thence exiting as in 46, and dissipating into air beneath the
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trap. A constant velocity of directed air 42, passing over the device containing
insect attract ants or extenuates 34 causes the attract ants or extenuates to be carried
by the air stream, in a vapor plume 48 and dissipated with exiting air 46.
Figure 5 illustrates the probable flight path of an insect 50 entering the trap. The
insect 50, in this case a house fly, is approaching the trap 10 in a meandering
fashion, attracted by the light radiation in the visible and adjacent spectral
regions produced by the lamp 22, and by an insect attract ant contained in the
release device 34. Other embodiments could eliminate the use of the release
device 34 and attract ant. The insect 50 reaches the suction 44 created by the
trap, shown at 52, and becomes entrapped in the flow of air. It is then carried, as
in 54, to the bottom of the collection device 36. The insect 50 is held down by the
exiting air I and can not escape from the trap, as in 56.
The dimensions of the trap 10 are dictated by the type of insect to be trapped and
would be determined by one skilled in the art. However, it has been found that,
for example, a trap for use in trapping house flies could have a diameter of six
inches and a height of 12 inches, excluding the collection device 36. The
collection device 36 could be of six inches diameter and 8 inches depth.
The trap is so designed that smaller beneficial insects are not injured when blown
into the collecting device and in this embodiment can escape through the mesh. If
such beneficial insects are not present, the collecting device could contain a non-
volatile toxic bait or contact insecticide to kill trapped insects. Other
embodiments could include still other devices to prevent the escape of the insect
pests, such as a counterbalanced valve or valves that close when the air flow
stops. In this way insects would be retained in the trap during power failures or if
the trap were operated intermittently by a timing switch. It is obvious that the
trap could include an outer cover to protect the fan and lamp while still allowing
insects free access to the lamp and its surrounding air stream.
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