ENVIRONMENTALLY FRIENDLY DISINFESTATION METHOD OF AN ENCLOSED SPACE AND APPARATUS FOR PERFORMING SUCH METHOD

The present invention relates to an environmentally friendly disinfestation method of an enclosed space and to an apparatus for performing such method. It is known to perform disinfestations in order to eliminate pests in a controlled atmosphere. Disinfestations are performed in sealed enclosed spaces and are characterized by very low oxygen contents of around 1%.

Entomological studies on low-oxygen disinfestation have in fact focused on verifying the effectiveness of treatments with low oxygen contents on different families of insects.

Past studies have shown a close correlation between the duration of the treatments with low residual oxygen percentages (1 %, ..., 2%) and temperature in the enclosed spaces used in the treatments.

Experiences and studies have confirmed that, with temperatures below 18 ^C C, the metabolism of insects in their four stages of development (egg, larva, pupa and adult) slows down to the point of forcing treatment times that are so long as to become uneconomical.

Another disadvantage of using such low residual oxygen contents is the need to resort to high-performance machines and tightly sealed enclosed spaces for the disinfestation treatments. That in practice forces the creation of special enclosed spaces and therefore to invest heavily in order to create suitable disinfestation centers.

On such a basis, it is unfeasible to perform low-oxygen disinfestation of means of transport, such as trains, aircraft, buses and other means of transport, both due to the high costs and to logistical difficulties in finding easily reachable spaces wherein it is possible to create facilities suitable for traditional low-oxygen treatments.

The aim of the present invention is to provide a method and an apparatus that overcome the drawbacks of the prior art.

A particular object of the invention is to provide a disinfestation method which is environmentally friendly and quick and particularly suitable for the disinfestation of means of transport.

Another object of the invention is to minimize installation times of the apparatuses required for the treatment.

Another object is to provide a method and an apparatus that allow a reduction in energy consumption. Another object of the invention is to provide a method and an apparatus that are versatile, i.e., can be used to disinfest enclosed spaces of all kinds.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by an environmentally friendly disinfestation method of an enclosed space, characterized in that it comprises the steps of: isolating an environment to be disinfested creating an enclosed space; reducing the percentage of oxygen of the atmosphere of the enclosed space to be disinfested to values comprised between 3% and 7%; keeping said enclosed space at a temperature comprised between 38°C and 48°C for a period of time comprised between 20 and 48 hours. This aim and these and other objects, that will become better apparent hereinafter, are also achieved by an apparatus for the environmentally friendly disinfestation of an enclosed space, comprising a means for reducing the percentage of oxygen in the atmosphere of the enclosed space to be treated, and a conveyance means for conveying said mixture of gases into said enclosed space, characterized in that said conveyance means comprises a hermetic connection device applied to an opening of said enclosed space so as to isolate said enclosed space with respect to the outside environment.

Further characteristics and advantages will become better apparent from the following detailed description of preferred but not exclusive embodiments of the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a schematic view of an embodiment of the disinfestation apparatus according to the present invention;

Figure 2 is a perspective view of the inflatable structure of the apparatus of Figure

1 ; Figure 3 is a schematic view of a further embodiment of the disinfestation

apparatus according to the present invention;

Figure 4 is a front view of the apparatus of Figure 3; Figure 5 is a partial side view of the apparatus of Figure 4. The disinfestation method according to the present invention includes using residual oxygen values comprised between 3% and 7% in the atmosphere of the enclosed space to be disinfested and keeping the enclosed space or the objects to be disinfested at a temperature comprised between 38°C and 48°C for a period of time comprised between 20 and 48 hours.

These conditions can be achieved inside most existing means of transport, by means of the apparatus according to the present invention.

In particular, in order to be able to maintain temperatures between 38°C and 48 ^C C inside the means of transport to be treated, it is normally sufficient to be able to operate and control the ordinary heating system of the means of transport themselves, besides of course introducing a stream of heated gas, with the chosen oxygen characteristics. Particularly in spring, autumn and especially in summer, maintaining these temperature values for the indicated periods entails neither difficulties nor high energy consumption.

Likewise, reaching and maintaining residual oxygen values comprised between 3% and 7% within the vast majority of means of transport and/or closed enclosed spaces does not entail particular technical difficulties or considerable energy consumption.

In particular, in order to maintain these oxygen values within the means of transport and/or the rooms to be equipped it is sufficient to create inside them a slight overpressure, so as to not allow the oxygen that is present in the external air, approximately 21 %, to enter. The figures illustrates some embodiments of the apparatus according to the invention.

In particular, Figures 1 and 2 illustrate a disinfestation apparatus, generally designated by the reference numeral 1 , comprising a nitrogen generator, which can be of any technology (PSA, VSA, membrane or burner) or an oxygen absorber 2. The currently preferred technology for the nitrogen generator is membrane

technology, the membranes having, at the percentages of oxygen used in the specific case, unquestionable advantages in terms of cost, weight, dimensions and performance.

A heater 3 brings the mixture of gases generated by the generator 2 to the chosen temperature. A gas intake pipe 4 is associated with a hermetic connection device, generally designated by the reference numeral 5, which is applied to an opening of the enclosed space 6 to be disinfested, which in turn is associated with an internal duct 7 which lies within the enclosed space 6 along a long extent, so as to not create a short-circuit between the gas intake and the outlet of an overpressure valve 8, which is comprised within the connection device 5; such a short-circuit would increase the oxygen suppression time.

The apparatus also comprises a residual oxygen analyzer 9, provided with a pipe 10 for the withdrawal of the analysis.

In this example, the hermetic connection device 5 is particularly suitable for the connection of the generator 2 to an enclosed space 6 which is provided with an entrance door 11 , as in the case of an access door of a rail car or of the passenger cabin of an airliner.

In this case, the connection device 5 has an inflatable structure which is similar to an inflatable mattress, as shown more clearly in Figure 2. The inflatable structure is arranged at the door 1 1 and subsequently inflated until it completely fills the empty space inside which partitioning is to be created.

As an alternative, when the hinges or closure mechanisms of the door/hatch or window 11 do not allow adequate placement, it is possible to arrange the inflatable structure inside a connecting corridor. This is the typical situation of many rail cars, in which it is usually not possible to arrange the inflatable structure directly on the entrance door, because of the steps for access to the rail car and to the mechanisms for closing the door, that do not allow the inflatable structure to sealingly close the geometric irregularities of the opening 11.

In this case, the inflatable structure is arranged a few centimeters inside the rail car, in the corridor for accessing the compartments.

The corridor has in fact a geometric regularity which allows excellent partitioning.

The inflatable structure has one or more air-filled chambers 12 and a central band 13 made of rubber or the like, which is arranged perimetrically in order to increase friction with the supporting surfaces. For the inflation of the structure there is an inflation valve 17 having a pressure reduction unit and an opening/closure gate valve.

The inflatable structure has a safety valve 16 for discharging the overpressures and a sleeve 14 to allow quick deflation of the inflatable structure.

When the sleeve 14 is not used, it remains rolled up and blocked by a locking system such as snap buttons , "Velcro" or other fastening systems.

The inflatable structure also has a flange 15 for connection to the pipe 4 of the nitrogen generator 2. The flange 15 includes the already-mentioned valve 8 for discharging the overpressure generated by the introduction of nitrogen in the enclosed space to be disinfested. The discharge valve 8 can be constituted by a disc which is mounted obliquely and pivoted on the upper side, its weight being chosen in order to maintain a very specific overpressure in the enclosed space to be disinfested.

The surface of the plate is such as to ensure a low speed of the output flow, which ensures a good acoustic comfort in venting. The operation of the generator is controlled by the residual oxygen analyzer 9, which analyzes the mixture of the gas produced by the generator and also analyzes the percentage content of residual oxygen, by means of a pipe 10 connected with the enclosed space to be disinfested.

When the residual oxygen percentage has reached the required value, the oxygen analyzer 9 informs the nitrogen generator 2, which throttles its generation of mixture with low oxygen content to a minimum which is sufficient to maintain a slight overpressure in the enclosed space to be disinfested.

In this manner, a considerable energy saving is achieved with respect to a continuous operation in the steady state of the machine. Tests conducted have in fact shown that very often even just 20% of the potential

of the machine is sufficient to maintain the residual oxygen constant at the value required by the disinfestation process.

Figure 3 illustrates an embodiment of the connection device, designated by the reference numeral 105, which can be used when the means to be partitioned and connected has a ventilation system with an entrance grille/grating 1 1 1 which allows easy access.

The connection device 105 includes a flange 1 17 which is equipped with hooks 118 and an inflatable air chamber 1 19.

The air chamber 1 19 has external overall dimensions that are greater than those of the grating/grille 1 1 1 to which it is coupled.

The hooks 1 18 allow easy engagement to the grating/grill. Once the hooks have engaged, the air chamber is inflated.

By inflating, the air chamber 1 19 tries to move the flange 1 17 away from the grille 1 1 1 , and since the hooks 1 18 do not allow the flange 1 17 to separate, an engagement and partitioning, which is sufficiently hermetic to the ventilation duct of the room and/or means of transport to be disinfested, is created automatically and immediately.

The flange 1 17 connects the enclosed space to be disinfested 106 to the nitrogen generator or oxygen absorber by means of the pipe 4 and the internal duct 7, as in the preceding example. In practice it has been found that the invention achieves the intended aim and objects, a method and an apparatus having been provided for a disinfestation treatment which can have an extremely high effectiveness on adult insects and is capable of achieving a 100% mortality rate of the adult population of pests in no more than 48 hours.

The brief duration of the treatment is extremely useful in the case, for example, of application of the disinfestation treatment to rail cars, aircraft or other means of mass or personal transport, that require to reduce any downtime, so as to minimize the lost profit and/or the losses caused indeed by idle periods.

Another important advantage of the invention is constituted by the fact that it allows to "partition" rapidly an enclosed space and connect it directly to the nitrogen generator and/or oxygen absorber required in order to be able to perform environment-

friendly disinfestation.

The method and the apparatus according to the invention minimize the preparation and installation time of the equipment in the enclosed space to be disinfested. In particular, the method and the apparatus according to the present invention, when applied for example to the disinfestation of trains, aircraft, buses and other means of transport in general, have many advantages, such as first of all the minimization of times and costs for preparing for disinfestation.

Another important practical advantage is that, in the vast majority of cases, it is not necessary to create any structure or sealed enclosed space into which the vehicle to be disinfested is to be introduced. The external structure of the vehicle in fact almost always has gas-tightness characteristics that, no matter how minimal, are sufficient to ensure the good outcome of treatment.

The volume inside which the oxygen level is to be reduced, if the tightness of the vehicle is sufficient, is minimized, and this means using less powerful machines and using the machines more effectively for the treatment, because the volume to be treated is indeed reduced only to the inner volume of the means of transport to be disinfested and with reduced energy consumption.

This application claims the priority of Italian Patent Application No. MI2006A001209, filed on June 23, 2006, the subject matter of which is incorporated herein by reference.