WO2016195515A1

WO2016195515A1 - Bait or poison dispenser

Info

Publication number: WO2016195515A1
Application number: PCT/NZ2016/050091
Authority: WO
Inventors: Craig Richard Bond; Robert Blair Van Dam; Stuart William Barr
Original assignee: Goodnature Limited
Priority date: 2015-06-02
Filing date: 2016-06-02
Publication date: 2016-12-08

Abstract

A bait or poison dispenser is arranged to dispense bait or poison over a long time period. The dispenser may be used in conjunction with an animal trap. The dispenser includes a bait or poison chamber holding a bait or poison and an outlet for dispensing of the bait or poison. A slow release gas generator is separated from the bait or poison by a membrane or pouch. As gas is generated by the gas generator, the pouch fills or the membrane moves to force bait or poison from the bait or poison chamber through the outlet.

Description

BAIT OR POISON DISPENSER

FIELD OF THE INVENTION

The invention relates to a bait or poison dispenser. More particularly but not exclusively, the invention relates to a bait or poison dispenser including a slow release gas generator. BACKGROUND TO THE INVENTION

Animal traps are used to control various pests such as mice, rats, stoats, possums and ferrets. Bait is included with traps to lure pests to the traps. Typically fixed baits are used, such as peanut butter or the like. Fixed baits are simply applied to a part of the trap and will slowly degrade over time.

However, in some applications it is desirable to renew the bait, so that it remains fresh over a long time period. Bait dispensers gradually dispense bait (and/or poison) over time to continually attract pests or other animals to long-life traps. One example of such a bait dispenser is found in the Applicant's New Zealand Patent No. 587778.

In non-pest management applications, dispensers have been proposed in which viscous substances are gradually pushed out of a chamber due to a surrounding or adjacent chamber being filled with gas.

A disadvantage of such dispensers is that the dispensing mechanisms are complex which makes them relatively difficult and expensive to manufacture. Further, the electronics of such dispensers are not encapsulated and are therefore susceptible to damage from the environment. There may also be a risk that the gas will be ignited by the electronics of the gas generators. The membranes used in the gas-dispensers are elastic and therefore partially gas-permeable, which decreases the life-span of the dispensers. Finally, the dispensers fail to include simple activation-mechanisms for deployment. Reference to any prior art in this specification does not constitute an admission that such prior art forms part of the common general knowledge.

It is an object of the invention to provide an improved bait or poison dispenser or at least to provide the public with a useful choice.

SUMMARY OF THE INVENTION

In one aspect the invention provides a bait or poison dispenser including:

a. a bait or poison chamber holding a bait or poison;

b. an outlet for dispensing of the bait or poison from the bait or poison chamber; c. a slow release gas generator; and

d. a flexible, gas-impermeable pouch or membrane separating the slow gas generator from the bait or poison, wherein, in use, as gas is generated by the slow release gas generator, the pouch fills or the membrane moves to force bait or poison from the bait or poison chamber through the outlet.

Preferably the gas generator generates hydrogen. Preferably the gas generator is a short circuited battery. Alternatively the gas generator releases compressed gas, or releases gas by the reaction of two reactants.

Preferably the gas generator releases gas at a rate of between 0.1 to 4 ml daily. Preferably the rate of gas release is controllable. Preferably the rate of gas release is controllable by a micro controller or variable resistor.

Preferably the gas generator is mechanically activated. Preferably the gas generator is activated by a magnetic switch. Preferably the magnetic switch includes a moving magnet and the gas generator is activated by removal of a magnetic element thereby allowing the moving magnet to move.

Alternatively the gas generator is activated by a reed switch. Preferably the gas generator is activated by the presence or absence of electrical conduction. Preferably movement of a part of the dispenser changes the electrical conduction. Preferably the bait is liquid. More preferably the bait is a viscous fluid.

Preferably the gas generator releases gas for over 6 months.

Preferably the dispenser includes a visible indicator of filling of the pouch or movement of the membrane.

Before the gas generator has been activated the outlet may be blocked by a cap, and wherein removal of the cap activates the gas generator. This aspect also extends to an assembly of a plurality of bait or poison dispensers, each as defined above, wherein the dispensers are sequentially activated, wherein the emptying of one dispenser's gas supply activates another dispenser.

The gas generator may be inside the pouch. Alternatively, the gas generator may be situated outside the pouch and fill the pouch with gas through a conduit.

The chamber may include channels to assist forcing of the bait or poison through the outlet. Preferably the chamber includes a thread to attach to an animal trap. The dispenser may be activated by removal of a cap from the thread.

The dispenser may be formed of three stacked layers of flexible material sealed together about their edges defining:

a. a gas chamber between an outer layer and the middle layer containing or in fluid communication with the slow release gas generator; and b. the bait or poison chamber between the other outer layer and the middle layer having an outlet and containing bait or poison;

wherein the middle layer forms the membrane separating the gas generator from the bait or poison. In another aspect the invention provides a bait or poison dispenser formed of three stacked layers of flexible material sealed together about their edges defining:

i. a gas chamber between an outer layer and the middle layer containing or in fluid communication with a slow release gas generator; and

ii. a bait or poison chamber between the other outer layer and the middle layer having an outlet and containing bait or poison,

wherein, in use, as gas is generated by the slow release gas generator, the gas chamber fills with gas to move the middle layer and force bait or poison from the bait or poison chamber through the outlet.

The slow release gas generator may be inside the gas chamber, or may be external to the gas chamber. Preferably the gas generator generates hydrogen.

Preferably the gas generator is a short circuited battery.

Preferably the gas generator releases gas at a rate of between 0.1 to 4 ml daily.

Preferably the rate of gas release is controllable. Preferably the rate of gas release is controllable by a micro controller or variable resistor.

Preferably the gas generator is mechanically activated.

Preferably the gas generator is activated by a magnetic switch. Preferably the magnetic switch includes a moving magnet and the gas generator is activated by removal of a magnetic element thereby allowing the moving magnet to move. Alternatively the gas generator may be activated by a reed switch.

Preferably the gas generator is activated by the presence or absence of electrical conduction. Preferably movement of a part of the dispenser changes the electrical conduction. Preferably the bait is liquid. More preferably the bait is a viscous fluid. Preferably the gas generator releases gas for over 6 months. In another aspect the invention provides a bait or poison dispenser including:

i. a bait or poison chamber holding a bait or poison;

ii. an outlet for dispensing of the bait or poison from the bait or poison chamber; iii. a slow release gas generator; and

iv. a flexible, gas-impermeable pouch within which the slow gas generator is sealed, the pouch being positioned within or adjacent the bait or poison chamber such that, in use, as gas is generated by the slow release gas generator, the pouch fills to force bait or poison from the bait or poison chamber through the outlet.

There is also provided a bait or poison dispenser including:

a. a bait or poison chamber holding a bait or poison;

d. a flexible, gas-impermeable membrane separating the slow gas generator from the bait or poison, wherein, in use, as gas is generated by the slow release gas generator, the membrane moves to force bait or poison from the bait or poison chamber through the outlet.

There is further provided a bait or poison dispenser formed of three stacked layers of flexible material sealed together about their edges defining:

i. a gas chamber between an outer layer and the middle layer containing a slow release gas generator; and

wherein, in use, as gas is generated by the slow release gas generator, the gas chamber fills with gas to move the middle layer and force bait or poison from the bait or poison chamber through the outlet. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example only, with reference to the accompanying drawings, in which:

Figure 1 A shows a cross-section of a bait or poison dispenser according to an embodiment of the invention;

Figure 1 B shows a cross-section of the bait or poison dispenser of Figure 1 A filled with bait;

Figure 1 C shows a cross-section of the bait or poison dispenser of Figure 1 A filled with the pouch partially expanded;

Figure 1 D shows a perspective view of the bait or poison dispenser of Figure 1 A; Figure 1 E shows an exploded view of the bait or poison dispenser of Figure 1 A; Figure 2A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention;

Figure 2B shows a cross-section of the bait or poison dispenser of Figure 2A with the pouch partially expanded;

Figure 2C shows a cross-section of the bait or poison dispenser of Figure 2A filled with the pouch almost fully expanded;

Figure 2D shows a perspective view of the bait or poison dispenser of Figure 2A; Figure 2E shows an exploded view of the bait or poison dispenser of Figure 2A; Figure 3A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention;

Figure 3B shows a cross-section of the bait or poison dispenser of Figure 3A with the bait over-half way dispensed;

Figure 3C shows a perspective view of the bait or poison dispenser of Figure 3A; Figure 3D shows an exploded view of the bait or poison dispenser of Figure 3A; Figure 4A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention;

Figure 4B shows a cross-section of the bait or poison dispenser of Figure 4A with the pouch partially expanded;

Figure 4C shows a cross-section of the bait or poison dispenser of Figure 4A with a first section partially filled with gas;

Figure 4D shows a cross-section of the bait or poison dispenser of Figure 4A with a first section almost fully filled with gas; shows a perspective view of the bait or poison dispenser of Figure 4A; shows an exploded view of the bait or poison dispenser of Figure 4A; shows a cross-section of a bait or poison dispenser according to another embodiment of the invention;

shows a cross-section of the bait or poison dispenser of Figure 5A with the pouch partially expanded;

shows a cross-section of the bait or poison dispenser of Figure 5A with a first section partially filled with gas;

shows a cross-section of the bait or poison dispenser of Figure 5A with a first section almost fully filled with gas;

shows a perspective view of the bait or poison dispenser of Figure 5A; shows an exploded view of the bait or poison dispenser of Figure 5A; is a cross-section through a bait or poison dispenser according to a further embodiment;

is another cross-section through the bait or poison dispenser of Figure

5A, with the first section partially filled with gas;

is a further cross-section through the bait or poison dispenser of Figure

5A, with the first section filled with gas; and

is a perspective view of the bait or poison dispenser of Figure 6A.

DETAILED DESCRIPTION

The invention relates to a bait or poison dispenser, which may be used to lure animals to animal traps or gradually dispense poison over a long period of time. The bait or poison dispenser includes a slow release gas generator which generates gas which forces bait or poison from a bait or poison chamber through an outlet. As will be discussed with reference to a number of embodiments, the slow gas generator may be sealed within a pouch within or adjacent a bait or poison chamber, or it may be separated from the bait or poison by a membrane.

Gas generator

The gas generator may be an electro-chemical gas generator which releases gases such as hydrogen, oxygen, or carbon dioxide. For example, a short-circuited battery may be used to produce hydrogen gas. For many applications zinc-air batteries may be suitable. In general any battery that produces gas when short-circuited may be suitable.

The generator is preferably able to produce gas at a slow and steady rate. A suitable rate for a long-life bait dispenser as shown in the embodiments below may be between 0.1 ml to 4ml, or 0.2 to 4ml, or 1 to 4ml, or 2 to 4ml (at room temperature and pressure) daily. The rate of dispensing will depend to some extent on temperature, with lower temperatures leading to lower pressure from the generated gas and therefore a lower rate of dispensing. However, the rate of gas-release will depend on the potency of the bait/poison, the amount of bait, and/or the desired life-span or service period of the trap. For example, in some conservation applications it may be desirable for a trap to be serviced around once a year. The rate of gas release may be such that the available volume of bait is dispensed over that time period. The rate of release may be controllable and/or adjustable. For example, a short- circuited battery gas generator may include a variable resistor for adjusting the rate of hydrogen production. In other embodiments, a microcontroller may be included to control the rate of gas release. Other possible gas generators include compressed gas housed in (and slowly released from) a micro-porous structure, or two non-gaseous reactants reacting to produce gas. In another embodiment, a diurnal pump may release gas using environmental air- pressure differences, or the temperature differences between day and night. It may be desirable to include a method of varying the release of gas to accommodate environmental temperature fluctuations (as this affects the volume of the gas and therefore the amount of bait which is forced out from the dispenser). For example, if a microcontroller is provided it may receive a signal from a temperature sensor and adjust gas generation appropriately.

Bait and/or poison

The dispenser may dispense bait, either for use in an animal trap or for some other purpose. The type of bait will depend on the type of animal being lured. The bait may include animal food, or substances including pheromones. The bait may be a viscous solid (such as a gel, paste or dry mix) or a liquid bait. In the case of liquid baits, a bait- holder may be required to retain the bait after it has been dispensed (for example, as disclosed in the Applicant's NZ Patent No. 587778).

The dispenser may alternatively be used to dispense poison. This may be used independently or in combination with an animal trap. In some embodiments the dispenser may dispense a combination of bait and poison.

Long-life

The dispenser is preferably able to dispense bait and/or poison over a relatively long timeframe, preferably six months or longer. This reduces the need for the dispenser to be replaced and/or re-set.

An assembly of bait or poison dispensers may be provided wherein the dispensers are sequentially activated. For example, the emptying of one dispenser's gas supply may activate another dispenser by mechanical or other means. Several dispensers may be controlled by a single controller. Alternatively, activation of dispensers may be remotely controlled.

Gas Generator Initiation

The dispenser preferably includes an activation mechanism for the gas generator, such that the generator does not release gas until it has been deployed. To protect the gas generator from the environment and also reduce the risk of gas ignition, the generator is preferably encapsulated, for example it may be situated inside the dispenser. In cases where an electrochemical gas generator is integrated into the bait dispenser chamber, the generator may be activated by some form of physical activation, such as by twisting the bait dispenser chamber to compress the gas generator circuit to switch it on. The circuit board may be pinched through the chamber to turn it on or off. Alternatively, inertial force may be used to activate the gas generator. For example, shaking the bait dispenser with sufficient force may release a retained ball to move and close the electrical contacts.

Activation involving the presence or absence of magnetic force is also possible. For example, the gas generator may include a reed switch which is turned on when a magnet is removed, or applied. Electrical shorting (by a conductive part on the surface of the body) or magnetic switching (e.g. removal of a steel cap to activate) may also be used to activate the gas dispenser.

Activation may be induced by various signals, temperatures, radiations or any other suitable activation methods.

Pouch

In the embodiments shown in Figures 1 A to 3D, the gas generator releases gas into a pouch which expands to force bait or poison out from the bait dispenser. The pouch provides a membrane separating the gas generator from the bait or poison. The pouch is preferably sealed and flexible. As discussed above, in some embodiments the pouch will contain the gas generator, whereas in other embodiments the gas generator may be external to the pouch and introduce gas into the pouch through a conduit.

The pouch is preferably made from a gas-impermeable material (which in most cases will be non-elastic). Possible materials include barrier foils (e.g. a polymer film with a layer of aluminium foil), or metalized films.

The dimensions of the pouch should be proportional to those of the bait chamber, such that in an expanded state the pouch substantially fills the bait chamber.

In a non-expanded state the pouch may have a circular, hexagonal or square shape. The shape of the pouch preferably matches the shape of the bait chamber. In an expanded state, the pouch may be spheroidal, and have a diameter between 80 to 100mm.

Chamber

In the embodiments shown in Figures 1 A to 3D which include pouches, the chamber includes a hard-shelled exterior.

The chamber may be configured with ribs or channels creating pathways for the bait to pass through when the pouch inflates. The ribs or channels allow inflation of the pouch without blocking flow-paths to the bottle exit. As will be illustrated by some of the embodiments described below, the channels may be included, for example, near the top of the bait chamber, or the bottom of the bait chamber, or extending alternately from the top and the bottom of the bait chamber. The chamber may include features to integrate with an animal trap (for example, in the embodiment of Figures 1 D to 1 E below, the lower-part of the chamber includes a thread to screw onto an animal trap).

The chamber may be configured to provide a visible indication of when the bait or gas supply has been exhausted. For example, the chamber may include a transparent window, which shows an indicator (e.g. a red circle) when the pouch has been fully inflated. This window may be at the top of the chamber.

In the embodiments shown in Figures 4A to 5F, the chamber includes a flexible exterior. In those embodiments the chamber may comprise a gas-impermeable material (which in most cases will be non-elastic). Possible materials include barrier foils (e.g. a polymer film with a layer of aluminium foil), or metalized films.

Embodiments

The embodiments shown in Figures 1 A to 3D include a pouch located inside a hard- shelled bait chamber along with the bait, and the expansion of the pouch within the chamber forces the bait out from the chamber.

The embodiments shown in Figures 4A to 5F show a flexible-chambered arrangement in which a membrane separates a bait section from a gas containing section.

Although the embodiments described below will refer to bait, this may be replaced with poison or a combination of bait and poison. Figure 1 A shows a cross-section of a bait or poison dispenser 1 according to an embodiment of the invention. The dispenser 1 includes chamber 2 comprising a top portion 2a and a bottom portion 2b. The top portion 2a may be attached to the bottom portion 2b during manufacture and/or may be detached from the bottom portion 2b for repair or refilling of the dispenser 1 . A seal 10 between the top portion 2a and the bottom portion 2b provides a fluid seal. Within the chamber there is a pouch 6, shown in a deflated state. A gas generator 5 (in this embodiment a battery) is situated in a side-wall of the bottom portion 2b of the chamber 2. The gas generator 5 may be activated, for example, by twisting the two portions of the chamber relative to each other, thereby creating electrical contact. An outlet 4 is provided at the bottom portion 2b. A number of ribs 7 extending from the outlet form channels to help force the bait 3 through the outlet 4. Below the outlet is a threaded neck 8, which may screw into/secure to an animal trap (not shown).

Figure 1 B shows a cross-section of the bait or poison dispenser of Figure 1 A filled with bait 3. The bait 3 fills substantially all of the space in the chamber below the pouch 6. At this stage, the dispenser has not yet been activated, and the pouch 6 has not been filled with any gas.

Figure 1 C shows a cross-section of the bait or poison dispenser of Figure 1 A with the pouch 6 partially inflated/expanded by being filled with gas. The pouch 6 occupies approximately half of the volume within the chamber 2 and has thus displaced/forced a large portion of the bait 3 through the outlet 4, out from the chamber 2.

Figure 1 D shows a perspective view of the bait or poison dispenser 1 of Figure 1 A. The chamber 2 of the dispenser 1 is substantially cylindrical. The top portion 2a of the chamber 2 includes a number of recesses 9, providing grip to allow a user to activate and deactivate the trap.

Figure 1 E shows an exploded view of the bait or poison dispenser of Figure 1 A. This shows the pouch 6 including two layers of material, and the gas generator 5 located inside the pouch 6 between the two layers of the pouch material. The pouch 6 is of a substantially circular shape. Figure 1 E also shows a shaped metal strip 5' which is compressed when the two halves of the chamber 2 are forced together. This compression creates an electrical short-circuit to activate the generation of gas.

Figure 2A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention. The chamber 2 is filled entirely with bait, and the pouch 6 is situated in the middle of the chamber. The gas generator (battery) 5 is positioned on a platform 15 near the outlet 4 of bait chamber 2 and removal of a cap 1 1 activates gas release. The cap 1 1 includes a magnet 20 which acts on a magnetic switch on a circuit board positioned beneath the battery. To activate the dispenser 1 , removal of the cap 1 1 removes the magnet 20, allowing the switch to close, short-circuiting the battery to release gas. As discussed above, gas release may be activated by a number of other suitable methods. For example, the gas generator may include a reed switch which detects the removal of magnet in the cap.

In other embodiments a mechanical arrangement may keep a contact open until the cap or some other element is removed. Once removed a spring or resilient element may force the contact to close.

Figure 2B shows a cross-section of the bait or poison dispenser of Figure 2A with the pouch partially expanded. Part of the bait 3 is being forced through the outlet 4. Figure 2C shows a cross-section of the bait or poison dispenser of Figure 2A filled with the pouch almost fully expanded.

Figure 2D shows a perspective view of the bait or poison dispenser of Figure 2A. The chamber includes a transparent window 12 to provide a visual indication of how much the pouch has been inflated and how much bait is remaining. The chamber also includes channels 13, which form ridges on the inside of the chamber creating pathways for the bait 3 to pass through when the pouch inflates, alternating from the top and the bottom of the bait chamber. Figure 2E shows an exploded view of the bait or poison dispenser of Figure 2A. The flattened pouch is hexagonal, and includes a housing 14 placed between the two layers 6a and 6b of the pouch 6. The housing 14 houses the gas generator 5 and connects to the platform 15 supporting the gas generator 5 and connecting it to the chamber 2. Figure 3A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention. In this embodiment, a moveable piston 16 is provided between the bait 3 and the pouch 6. The piston 16 is movable with respect to longitudinal axis of the cylindrical chamber 2. Figure 3B shows a cross-section of the bait or poison dispenser of Figure 3A with the bait 3 over-half way dispensed. The piston 16 has been pushed downwards towards the outlet 4 as the pouch has expanded, forcing out bait 3 through the outlet. Figure 3C shows a perspective view of the bait or poison dispenser of Figure 3A. The dispenser has a substantially cylindrical shape.

Figure 3D shows an exploded view of the bait or poison dispenser of Figure 3A. The pouch 6 includes a first layer 6a and a second layer 6b, and the gas generator 5 is integrated into the second layer 6b of the pouch 6. The gas generator (battery), or more specifically the housing 14, may be welded to the second layer 6b of the pouch 6.

Figure 4A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention. The chamber 2 in this embodiment is formed of a flexible material rather than a hard material. The chamber 2 is separated into two sections 18 and 19 by a membrane 17. The first section 18 contains the gas generator 5, and the second section 19 contains the bait (not shown in Figure 4A). The gas generator 5 is freely contained within the first section 17 which expands as it is filled with gas.

Figure 4B shows a cross-section of the bait or poison dispenser of Figure 4A in an inactivated state. The second section 19 is filled with bait, and the first section 18 substantially empty (not filled with gas). The chamber 2 assumes an oblate spheroidal shape as the second section 19 is filled with bait 3 and the membrane 17 is pushed towards a top portion 2a of the chamber 2.

Figure 4C shows a cross-section of the bait or poison dispenser of Figure 4A after activation, with the first section 18 partially filled with gas. The membrane 17 is forced towards the middle of the chamber 2 by the expansion of the first section 18, forcing the bait 3 out from the outlet 4.

Figure 4D shows a cross-section of the bait or poison dispenser of Figure 4A near the end of its lifespan, with the first section 18 almost fully filled with gas. The membrane 17 is forced towards the outlet 4, and the second part 2a of the chamber 2 by the inflation of the first section 18. The majority of the bait 3 has been forced from the chamber 2 through the outlet 4.

Figure 4E shows a perspective view of the bait or poison dispenser of Figure 4A. The filled chamber 2 is an oblate spheroid. The chamber 2 maintains this shape throughout the lifespan of the dispenser 1 as the dispenser is filled with bait, which is eventually displaced with gas, maintaining the volume of the chamber 2 substantially constant.

Figure 4F shows an exploded view of the bait or poison dispenser of Figure 4A. This shows the three layers of the dispenser including the top portion 2a of the chamber, membrane 17 and bottom portion 2b of the chamber. The gas dispenser 5 is situated between the top portion 2a of the chamber and the bottom portion 2b of the chamber. The bottom portion 2b of the chamber contains the outlet 4. Figure 5A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention. In this embodiment, the gas dispenser 5 (battery) is integrated into the top portion 2a of the chamber 2. The gas dispenser 5 is welded to exterior of the top portion 2a (e.g. foil layer) using any suitable welding process. Similarly the foil layers may be welded to each other using any suitable welding process. Processes for joining foil layers and for joining component to foil layers are well known and need not be described here.

Figure 5B shows a cross-section of the bait or poison dispenser of Figure 5A with the second section 19 filled with bait. The chamber 2 assumes an oblate spheroidal shape as the second section 19 is filled with bait 3 and the membrane 17 is pushed towards the first part 2a of the chamber 2.

Figure 5C shows a cross-section of the bait or poison dispenser of Figure 5A with the first section 18 partially filled with gas. The membrane 17 is pushed towards the middle of the chamber 2, forcing the bait 3 out through the outlet 4.

Figure 5D shows a cross-section of the bait or poison dispenser of Figure 5A with the first section 18 almost fully filled with gas. The membrane 17 is pushed towards the outlet 4, and the second part 2a of the chamber 2. The majority of the bait 3 has been forced from the chamber 2 through the outlet 4. Figure 5E shows a perspective view of the bait or poison dispenser of Figure 5A. The filled chamber 2 is an oblate spheroid. The chamber 2 maintains this shape throughout the lifespan of the dispenser 1 as the dispenser is filled with bait, which is eventually displaced with gas, maintaining the volume of the chamber 2 substantially constant.

Figure 5F shows an exploded view of the bait or poison dispenser of Figure 5A. This shows the three layers of the dispenser including the top portion 2a of the chamber, membrane 17 and bottom portion 2b of the chamber. The gas dispenser 5 is situated between the top portion 2a of the chamber and the bottom portion 2b of the chamber. The bottom portion 2b of the chamber contains the outlet.

Figure 6A shows a cross-section of a bait or poison dispenser according to another embodiment of the invention. This embodiment is generally similar to that of Figures 5A to 5F.

In this embodiment, the gas dispenser 5 (battery) is integrated into the top portion 2a of the chamber 2. The battery 5 is mounted in a support 20, which is welded to exterior of the top portion 2a (e.g. foil layer). The structure of the support 20 and the switching arrangement used in this embodiment will be described in detail below.

Figure 6A shows the second section 19 filled with bait.

Figure 6B shows a cross-section of the bait or poison dispenser of Figure 6A with the first section 18 partially filled with gas. This cross-section is taken perpendicular to that of Figure 6A in order further to illustrate features of the support 20. The membrane 17 is pushed towards the middle of the chamber 2, forcing the bait 3 out through the outlet 4.

Figure 6C shows a cross-section of the bait or poison dispenser of Figure 6A with the first section 18 almost fully filled with gas. The membrane 17 is pushed towards the outlet 4. The majority of the bait 3 has been forced from the chamber 2 through the outlet 4.

Figure 6D is a perspective view of the bait or poison dispenser of Figure 6A. This drawing further illustrates the structure of the support 20. As shown in Figure 6A, the support includes a lower portion arranged to support a battery 5. The battery may be retained by any suitable features, such as protrusions 21 , caps, retainers etc. Figure 6A shows a magnetic switch in an "open" position. The magnet 22 is retained in a raised position in which it does not contact the battery 5. This is achieved through the presence of a ferromagnetic element 23 positioned on the support 20. The magnetic force between the magnet 22 and the ferromagnetic element 23 keeps the magnetic switch open, and also retains the ferromagnetic element 23 in position. In order to activate the dispenser 1 , a user removed the ferromagnetic element 23. This allows the magnet to move downwards (since it will be somewhat attracted to the battery 5) to the position shown in Figures 6B and 6C. Figure 6B shows a resistor 25 that is positioned beside the battery 5 and magnet 22. The lower end of the resistor 25 contacts the side of the battery 5. Downwards movement of the magnet 22, to the position of Figure 6B, brings it into contact with the upper end of the resistor 25 and also with the upper surface of the battery 5, thereby creating a circuit through the resistor 25, and causing the generation of gas to begin. The rate of gas production may be set by selection of an appropriate resistor. There is thus provided an improved bait or poison dispenser with a long life span. The dispenser is simple, inexpensive and easy to manufacture. As the gas dispenser is encapsulated, it is protected from the environment. The risk of the gas being ignited is also reduced. A non-elastic membrane provides a longer-life span of the dispenser as it has low permeability to gas. The dispenser includes a simple activation mechanism for when it is deployed.

While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Further, the above embodiments may be implemented individually, or may be combined where compatible. Additional advantages and modifications, including combinations of the above embodiments, will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the Applicant's general inventive concept.

Claims

1 . A bait or poison dispenser including:

a. a bait or poison chamber holding a bait or poison;

2. The dispenser of claim 1 wherein the gas generator generates hydrogen.

3. The dispenser of any one of the preceding claims wherein the gas generator is a short circuited battery.

4. The dispenser of claim 1 or claim 2 wherein the gas generator releases compressed gas. 5. The dispenser of claim 1 or claim 2 wherein the gas generator releases gas by the reaction of two reactants.

6. The dispenser of any one of the preceding claims wherein the gas generator releases gas at a rate of between 0.1 to 4 ml daily.

7. The dispenser of any one of the preceding claims wherein the rate of gas release is controllable.

8. The dispenser of claim 7 wherein the rate of gas release is controllable by a micro controller or variable resistor.

9. The dispenser of any one of the preceding claims wherein the gas generator is mechanically activated.

10. The dispenser of any one of the preceding claims wherein the gas generator is activated by a magnetic switch.

1 1 . The dispenser of claim 10, wherein the magnetic switch includes a moving magnet and the gas generator is activated by removal of a magnetic element thereby allowing the moving magnet to move.

12. The dispenser of any one of the preceding claims wherein the gas generator is activated by a reed switch.

13. The dispenser of any one of the preceding claims wherein the gas generator is activated by the presence or absence of electrical conduction.

14. The dispenser of claim 13 wherein movement of a part of the dispenser changes the electrical conduction.

15. The dispenser of any one of the preceding claims wherein the bait is liquid.

16. The dispenser of any one of the preceding claims wherein the bait is a viscous fluid.

17. The dispenser of any one of the preceding claims wherein the gas generator releases gas for over 6 months. 18. The dispenser of any one of the preceding claims including a visible indicator of filling of the pouch or movement of the membrane.

19. The dispenser of any one of the preceding claims wherein before the gas generator has been activated the outlet is blocked by a cap, and wherein removal of the cap activates the gas generator.

20. An assembly of a plurality of bait or poison dispensers, each as claimed in claim 1 , wherein the dispensers are sequentially activated, wherein the emptying of one dispenser's gas supply activates another dispenser.

21 . The dispenser of claim 1 wherein the gas generator is inside the pouch.

22. The dispenser of claim 1 wherein the gas generator is situated outside the pouch and fills the pouch with gas through a conduit.

23. The dispenser of any one of the preceding claims wherein the chamber includes channels to assist forcing of the bait or poison through the outlet.

24. The dispenser of any one of the preceding claims wherein the chamber includes a thread to attach to an animal trap.

25. The dispenser of claim 24 wherein the dispenser is activated by removal of a cap from the thread. 26. The dispenser of any one claims 1 to 18, formed of three stacked layers of flexible material sealed together about their edges defining:

wherein the middle layer forms the membrane separating the gas generator from the bait or poison.

A bait or poison dispenser formed of three stacked layers of flexible material sealed together about their edges defining:

28. The bait or poison dispenser of claim 27 wherein the slow release gas generator is inside the gas chamber.

29. The bait or poison dispenser of claim 27 wherein the slow release gas generator is external to the gas chamber.

30. The dispenser of any one of claims 27 to 29 wherein the gas generator generates hydrogen.

31 . The dispenser of any one of claims 27 to 30 wherein the gas generator is a short circuited battery. 32. The dispenser of any one of claims 27 to 31 wherein the gas generator releases gas at a rate of between 0.1 to 4 ml daily.

33. The dispenser of any one of claims 27 to 32 wherein the rate of gas release is controllable.

34. The dispenser of claim 33 wherein the rate of gas release is controllable by a micro controller or variable resistor.

35. The dispenser of any one of claims 27 to 34 wherein the gas generator is mechanically activated.

36. The dispenser of any one of claims 27 to 35 wherein the gas generator is activated by a magnetic switch. 37. The dispenser of claim 36, wherein the magnetic switch includes a moving magnet and the gas generator is activated by removal of a magnetic element thereby allowing the moving magnet to move.

38. The dispenser of any one of the claims 27 to 35 wherein the gas generator is activated by a reed switch.

39. The dispenser of any one of claims 27 to 38 wherein the gas generator is activated by the presence or absence of electrical conduction.

40. The dispenser of claim 39 wherein movement of a part of the dispenser changes the electrical conduction.

41 . The dispenser of any one of claims 27 to 40 wherein the bait is liquid.

42. The dispenser of any one of claims 27 to 41 wherein the bait is a viscous fluid.

43. The dispenser of any one of claims 27 to 42 wherein the gas generator releases gas for over 6 months.