Technical field

This invention relates to a dispenser of parasiticidal substances.

It is included in the sector of devices used for combating mosquitoes and other harmful insects, having a dual action: as an adulticide (against adult insects) and a larvicide (against larvae, in particular of mosquitoes), and therefore being both repressive and preventive.

Disinfestation of open environments (even urban ones) is necessary both for comfort, because sometimes the presence of such insects makes the use of parks, gardens and outdoor spaces impossible, and for health and hygiene reasons.

In particular, the need to perform massive and periodic disinfestations or similar treatments increased in Europe towards the early 2000s when the presence of mosquitoes arriving from South-East Asia, the so-called “tiger mosquitoes”, became constant. In fact, such mosquitoes are more dangerous than the common type because they are also active in the daytime, are very aggressive and are vectors of pathogenic agents which can transmit allergies or more serious diseases, such as encephalitis or even malaria.

Due to the health and hygiene aspects involved, the problem of combating mosquitoes has become the responsibility of public authorities, which constantly seek effective and efficient systems to put into practice and to suggest to citizens.

Background art

The main aspects to be considered when assessing the most suitable tools for combating mosquitoes, in addition to effectiveness, may be identified as the need to periodically intervene with cyclical treatments, the inexpensiveness of solutions adopted and the limitation of the environmental impact of such solutions.

A common feature of the different types of existing parasiticidal treatments is that they must be carried out cyclically, because the problem of mosquitoes appearing recurs on a seasonal basis, and they must be repeated multiple times during each seasonal cycle, since weather events, such as heavy rain, may compromise their effectiveness. That leads to a substantially continuous use over time of operators dedicated to this activity, and consequently a quite high cost to be borne by the public authorities.

For example, a device according to the document US 2005/0185940, designed for the controllable release of a volatile substance, involves the use of a dispensing chamber made of a flexible material, which fills with the fluid to be expelled and emits it following a compression of its walls carried out from the outside of the chamber.

Also, in this case the presence of an operator would be necessary to exert a compression on the walls of the dispensing chamber when it is deemed useful: therefore, automatic operation could not be obtained in the presence of a temperature increase.

A further problematic aspect of combating mosquitoes is the environmental impact, since both private citizens and specialised companies often use substances which are harmful to the environment and to human health, which are partly “dispersed” in the environment in a way that is not well targeted and not effective.

Disclosure of the invention

The aim of this invention is therefore to eliminate the above-mentioned disadvantages. This invention fits into that context and aims to solve the problem of combating mosquitoes in urban environments, where the main places for development of such insects are drains and large storm drains.

The invention, characterised as set out in the claims, achieves the aim thanks to a device activated by temperature changes.

The main advantage obtained by means of this invention basically consists of the fact that the emission of parasiticidal substances occurs without operator intervention and in a targeted way in the places where the concentration of larvae is assumed to be the greatest.

The automatic operation of the invention just coincides with the typical atmospheric situations, in which there is the maximum proliferation of harmful insects such as mosquitoes.

Moreover, in order to extend the effectiveness of the invention it is sufficient to periodically top up, in any case every few months, the parasiticidal substance.

Consequently, it is possible to achieve considerable savings and minimising of the environmental impact that the parasiticidal substances could have on the environment and on people.

Brief description of the drawings

Further advantages and features of the invention will be more apparent in the detailed description which follows, with reference to the accompanying drawings, which show an example, non-limiting embodiment, in which:

- Figure 1 illustrates a first embodiment of the invention according to a perspective assembly view;

- Figure 2 illustrates the invention of Figure 1 according to a longitudinal section perspective view; Figure 3 illustrates a detail of the invention in an operating condition;

Figures 4 to 6 illustrate the detail of Figure 3 according to an operating sequence;

- Figures 7 and 8 illustrate an alternative version of a detail of the invention in a longitudinal section;

- Figures 9 and 10 illustrate a second embodiment of the invention, respectively according to a perspective assembly view and according to a longitudinal section perspective view;

- Figure 11 illustrates a basic version of the invention in a longitudinal section.

Preferred embodiments of the invention

As can be seen from the figures, the invention relates to a dispenser of parasiticidal substances.

It can be made in various ways, depending on the parasiticidal substance used and according with its features, such as, for example, its expandability as a result of temperature changes or the fact that it is liquid or solid: in any case, operation of the dispenser 10 is always caused by an increase in the temperature.

A first embodiment, implementable if the parasiticidal substance is significantly expandable, is shown in Figure 11.

This embodiment involves the use of a tank 6, containing a parasiticidal substance (preferably liquid, but which could even be in a solid or gaseous state), leading to an ejection device 20 for expelling the parasiticidal substance, operated by expansion of the parasiticidal substance resulting from an increase in the temperature. Since the parasiticidal substance is subject to modification of its volume due to temperature changes, it is the latter that cause operation of the dispenser 10.

As seen in Figure 11, in this case the ejection device 20 comprises a containment chamber 14 for the parasiticidal substance with rigid walls 14b, communicating with the tank 6 by means of an opening 16 and provided with occlusion means 15 for closing that opening 16. At a lower end 14a of the chamber 14 there is a non-return valve 13 from which the parasiticidal substance is expelled.

The chamber 14 is gradually filled by gravity with the parasiticidal substance through the opening 16 which connects the tank 6 and the chamber 14; when the chamber 14 is full, the occlusion means 15, which in the example shown are in the form of a small ball 15a with lower density than that of the parasiticidal substance, block the opening 16 interrupting the transit of the parasiticidal substance. In this situation, when there is an increase in the temperature, the volume of the parasiticidal substance increases and part of it is expelled from the non-return valve 13; then when the temperature decreases and the parasiticidal substance occupies less space, the small ball 15a disengages from the opening 16 allowing the chamber 14 to fill up again.

Figure 11 also shows two control valves 4 which are oriented in opposite directions, which put the tank 6 in communication with the outside so as to prevent the creation of negative pressures inside it and to keep it isolated if it is immersed in water.

If the parasiticidal substance is not significantly expandable, it is necessary to provide the dispenser 10 with a second tank 2, placed upstream of the tank 6 containing the parasiticidal substance, which contains a substance suitable for supplying a propelling action as a result of an increase in the temperature.

In this case, shown in Figures 1 to 10, the dispenser 10 comprises a second tank 2 containing an expandable fluid, provided with a lower hole 21, a rigid piston 3 slidable inside the hole 21, a spring 9 suitable for opposing the descent of the piston 3 caused by the expansion of the fluid and for aiding its return ascent when the volume of the fluid is reduced, and the tank 6 containing a parasiticidal substance, leading to an ejection device 20 for expelling the parasiticidal substance, operated by the movement of the piston 3. Since the fluid is subject to modification of its volume due to temperature changes, it is these which in this case too cause operation of the dispenser 10.

The figures show two different embodiments of the dispenser 10, depending whether the parasiticidal substance is in the liquid state or the solid state: in particular, Figures 1 to 8 relate to the first version of the dispenser 10, whilst Figures 9 and 10 relate to the second version.

If the tank 6 contains a liquid parasiticidal substance, the ejection device 20 comprises a containment chamber 14 for the parasiticidal substance, at a lower end 14a of which there is a non-retum valve 13 from which the liquid is expelled. The sequence shown in Figures 3 to 6 shows how, when the volume of the fluid increases as a result of an increase in the temperature, the piston 3 is pushed downwards, moves forward in the chamber 14 drawing with it a sealing ring 11, which has a predetermined clearance both in the radial direction and in the axial direction relative to the piston 3, and causes the parasiticidal liquid to be expelled. Then when the temperature starts to fall again, the volume of the fluid is reduced and the piston 3, partly due to the action of the spring 9, ascends again creating a space 12 between itself and the sealing ring 11 which allows the parasiticidal liquid to gradually fill the chamber 14, both due to the effect of gravity and the effect of the decompression caused.

Alternatively, as seen in Figures 7 and 8, the piston 3 comprises an inner channel 31 for the passage of the parasiticidal liquid and closing means 32 for the channel 31, suitable for preventing the inflow of the parasiticidal liquid into the chamber 14 during expelling of the liquid. In the example embodiment shown, the closing means 32 for the channel 31 comprise a ball 32a with lower density than the larvicidal liquid, having dimensions matching the end part of the channel 31 which has the shape of a frustoconical hollow 31a.

If the tank 6 contains a solid parasiticidal substance, the ejection device 20, visible in Figures 9 and 10, comprises a pepper mill mechanism 30 formed by a grooved conical ring 33, by a helical surface 34 coaxial with the conical ring 33 and by a pierced grate 35, in such a way as to break up the parasiticidal substance by friction and deposit in on a surface below. In this case, the piston 3 comprises a threaded portion 3a threaded to match a support 36 to which the helical surface 34 is fixed: the longitudinal movement of the piston 3 thereby allows rotation of the helical surface 34 and rubbing of the helical surface 34 against the conical ring 33 causes the break up of the parasiticidal substance.

In all cases, regardless of whether or not the second tank 2 is present, whether or not the parasiticidal substance is in the liquid or solid state, the tank 6 comprises at least one movable portion of wall 61, suitable for shifting to allow topping up of the parasiticidal substance. In the example shown in Figures 1 and 9, the movable portion of wall 61 rests on an elastic element 62, in such a way as to yield to the pressure of an operator who performs the topping up and then return to the initial position under the action of the elastic element 62. Even if a second tank 2 is present, it is also appropriate for at least one control valve 4 to be applied to the tank 6 containing the parasiticidal substance, in such a way as to prevent negative pressures inside the latter and to prevent, for example, water from infiltrating inside it.