Optimized sanitization methd and sytem

Abstract

Method of sanitizing a surface comprising a step of treating said surface with a sanitizing fluid (F) consisting of a mixture of air and ozone, in which the ozone has a concentration between 0.5 and 200 ppm, for a time between 1 and 60 minutes.

Description

[0001] DESCRIPTION

[0002] OPTIMIZED SANITIZATION METHOD AND SYSTEM

[0003] TECHNICAL FIELD

[0004] The present invention relates to a method of sanitizing a surface and to a sanitization system, in particular an ozone sanitization system.

[0005] The present invention has a preferred, albeit not exclusive, application in the sanitization of textile materials. Reference will be made to this application below by way of example.

[0006] PRIOR ART

[0007] There are known sanitization systems and methods of various types for sanitizing materials of various nature, such as plastic or metal materials or fabrics.

[0008] Such systems became of primary interest during the recent period of the pandemic due to the SARS-CoV-2 virus.

[0009] Among the various existing sanitization systems, ozone sanitization systems are known. Such systems provide for treating the material to be sanitized by keeping it in a high-concentration ozone flow for a given period of time.

[0010] However, this high ozone concentration, though effective from a sanitization viewpoint, is extremely aggressive, particularly on fabrics. In fact, a fabric element sanitized by means of high-concentration ozone tends to discolour and deteriorate, as does a leather element, one made of non- passivatable metals or materials of another nature .

[0011] Furthermore , such large amounts of ozone are produced by means of systems that are energy- intensive or consume a great deal of oxygen .

[0012] On the other hand, a reduction in the ozone concentration, i f not controlled, would preclude an adequate saniti zation of the elements or require long times of exposure to ozone incompatible with commercial uses .

[0013] There is thus a felt need to improve the known saniti zation systems and methods in order to solve the abovedescribed problems without , however, compromising their saniti zation ef fectiveness .

[0014] The obj ect of the present invention is to satis fy the above-described needs in an optimi zed and economical manner .

[0015] SUMMARY OF THE INVENTION

[0016] The aforesaid obj ect is achieved by an ozone saniti zation system and an ozone saniti zation method as disclosed in the appended claims .

[0017] BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a better understanding of the present invention, a preferred embodiment is described below by way of nonlimiting example and with reference to the appended drawings , in which :

[0019] • Figure 1 is a perspective view of a saniti zation system according to the invention; • Figure 2 is a side view of the system in figure 1 ;

[0020] • Figure 3 is a side cross-section view according to the plane I I I- I I I in Figure 1 ;

[0021] • Figure 3a shows a detail with respect to figure 3 and

[0022] • Figure 4 is a functional diagram illustrating elements of a device of the saniti zation system of the invention . DETAILED DESCRIPTION OF THE INVENTION

[0023] In the appended figures , a saniti zation system according to the invention is generally indicated by the reference number 1 .

[0024] The saniti zation system 1 comprises a structure 2 configured to del imit a space 3 separated from the external environment .

[0025] The structure 2 essentially comprises a plurality of walls 2a, 2b, 2c connected together by means of a frame 2 ' , preferably grid-like .

[0026] In particular, the structure 2 has a substantially parallelepiped shape ; it thus comprises a lower wall 2a and an upper wall 2b opposite each other along a first vertical axis A and a plurality of side walls 2c, substantially a first pair of opposite side walls along a second transverse axis B, and a second pair of oppos ite side walls 2c along a third longitudinal axis C .

[0027] Advantageously, one of the side walls 2c, advantageously the front one , is hinged with respect to the frame 2 ' in order to enable access to the space 3 to fill it with elements to be saniti zed . Preferably, at least one of the side walls 2c can be made of transparent material .

[0028] The structure 1 further comprises a partition wall 2d housed within the space 3 and configured to divide the space 3 into two portions fluidically in communication with each other, speci fically, a first portion 3a and a second portion 3b . Conveniently, the wall hinged to the frame 2 ' defines a door . In a closed configuration the door extends in such a way as to be substantially transverse (preferably orthogonal ) to the partition wall 2d . Conveniently, the door, i f open, allows access both to the first and to the second portion 3a, 3b . In particular, the door, i f open, determines direct access to the first and to the second portion 3a, 3b .

[0029] In the described embodiment , the partition wall 2d extends from the lower wall 2a towards the upper wall 2b without touching the latter so as to provide the fluidic communication in that zone between the first and the second portion 3a, 3b of the space 3 . This advantageously allows for minimising the presence of dead zones within the space 3 . In an alternative solution, in an upper portion of the partition wall 2d there are one or more openings passing through the thickness of the partition wall 2d .

[0030] Therefore , the f irst and second portions 3a, 3b extend parallel along the axis A and are limited laterally by respective side walls 2c and by the partition wall 2d and vertically by the upper and lower walls 2b, 2a .

[0031] Likewise advantageously, the structure 2 comprises a bottom wall 2e parallel to the upper wall 2a and configured to delimit , along the vertical axis A, a third portion 3c of the space 3 , fluidically connected to the first and to the second portion 3a and 3b as described below . Conveniently, the third portion 3c is located below the first and second portions 3a, 3b .

[0032] As may be seen in figure 3 , the structure 2 also comprises a hous ing portion 2 ' ' situated below the bottom wall 2e and delimiting a space 19 housing an ozone generation system 20 , as better described below .

[0033] The saniti zation system 1 comprises ventilation means 10 configured to enable the recirculation of a flow of a gaseous saniti zing fluid F between the first and second portions 3a, 3b starting from the third portion 3c described above .

[0034] In particular, the ventilation means 10 comprise a fan configured to draw in the flow of fluid F from the third portion 3c and force it towards the first portion 3a . Conveniently, the fan has a vertical rotation axis . The fan is thus disposed hori zontally . Conveniently, the fan occupies at least 30% of the part of the lower wall 2a that is located in the first portion 3a . The fan enables the flow of fluid F to circulate between the first and second portions 3a, 3b, without dead zones .

[0035] In order to allow the recirculation of the aforesaid fluid F in the second portion 3b towards the third portion 3c, from where it will return towards the first portion 3a, the saniti zation system 1 comprises an aeration grid 11 configured to allow fluidic communication between the second portion 3b and the third portion 3c and thus provided through the lower wall 2a in the described embodiment . The grid is situated on the lower bottom of the portion 3b . Conveniently, the fan defines the only inlet zone in the first portion 3a for the flow of fluid F containing ozone . Therefore , there is not a plurality of access zones for the fluid with ozone in the first portion 3a .

[0036] Conveniently, the flow rate of the recirculating fluid F is between 3000 and 4000 m3 / h . This facilitates mixing between air and ozone . On average , therefore , the time it takes for the flow of fluid F to carry out a complete recirculation through the first , second, and third portions 3a, 3b, 3c is between 0 . 8 and 2 seconds .

[0037] The saniti zation system 1 can also comprise venting means 12 configured to selectively allow fluidic communication between the space 3 and the external environment . Advantageously, the venting means 12 comprise a fan selectively activatable to draw in the fluid F contained inside the space 3 and force it towards the outside . Conveniently, the saniti zation system 1 can comprise a catalytic cartridge 120 . For example , the latter makes it possible to reduce / minimi ze the ozone concentration in the fluid that is evacuated through the venting means 12 . Conveniently, the catalytic cartridge 120 can be located near the venting means 12 . Conveniently, the catalytic cartridge 120 can be positioned downstream ( or rather, immediately downstream of the venting means 12 ) . Conveniently, the catalytic cartridge 120 could have a volume of about 20 litres . Advantageous ly, it operates during at least a part of the saniti zation cycle . Conveniently, it operates for a period also at the end of the saniti zation cycle .

[0038] The saniti zation system 1 further comprises supporting means 13 , 14 for supporting elements to be saniti zed, advantageously clothes and accessories .

[0039] The supporting means can comprise bars 13 fixed to the structure 2 and configured for hanging the elements to be saniti zed or clothes hangers or the like for the latter . In the described embodiment , the bars 13 are borne by the upper wall 2b and extend along the longitudinal axis C and along the transverse axis B .

[0040] Conveniently, the first portion 3a can be intended to accommodate garments to be saniti zed . For example , they can be hung on the above-described hangers . Conveniently, in the first portion 3a there is an ascending flow of fluid F . It thus facilitates the saniti zation of the hung garments ( as they are hit from below and hung from above , the flow of fluid F will advantageously be able to pass over the garments internally and externally) .

[0041] The supporting means can comprise shelves 14 fixed (non- removably or removably to have , for example , greater flexibility) to the structure 2 and configured for resting the elements to be saniti zed ( for example clothing accessories ) . In the described embodiment , the shelves 14 are borne by supports 15 rigidly borne by the structure 2 .

[0042] In particular, the supports 15 are provided on the partition wall 2d and on a side wall 2c, extending towards each other, proj ecting in the second portion 3b and vertically spaced from each other, advantageously in an equal manner along the vertical axis A. Consequently, in the nonlimiting example embodiment illustrated, only the second portion 3b comprises the shelves 14 . Conveniently, the shelves 14 are grids or perforated . They are arranged one above the other . Conveniently, in the second portion 3b the flow of fluid F is descending . The saniti zation system 1 can also be movable relative to the ground, at least selectively .

[0043] Accordingly, the structure 2 can be provided with translation support means 16 , preferably borne by the housing portion 2 ' ’ . In particular , the translation support means 16 comprise castors placed substantially in proximity to the corners of the housing portion 2 ’ ’ .

[0044] As mentioned, the housing portion 2 ’ ’ defines a space 19 fluidically isolated from the space 3 and communicating with the external environment , for example a calibrated opening .

[0045] Similarly to what was described above for the space 3 , the space 19 is delimited by a plurality of walls , in particular by the aforesaid side walls 2c, the aforesaid bottom wall 2e and a lower terminal wall 2 f .

[0046] In detail , the saniti zation system 1 comprises an ozone generation system 20 housed in the space 19 and configured to inj ect into the space 3 a prede fined amount of ozone and a predefined net flow o f air, which, being mixed in the space 3 thanks to the ventilation means 10 , generates the aforesaid gaseous saniti zing fluid F .

[0047] In particular, the aforesaid predefined amount of ozone can range from 1 to 9 g / m3per hour and advantageously from 1 to 4 g / m3per hour .

[0048] As may be better seen in figure 3 , the ozone generation system 20 comprises , housed in the space 19 , an ozone generator 22 . The ozone generator 22 is fluidically connected, for example by means of respective conduits , to the space 3 in order to inj ect ozone into it .

[0049] Preferably, housed in the space 19 there can be air filtering means 21 configured to introduce air into the space 3 by drawing it in from the external environment according to need, as necessary to supply the aforesaid gaseous saniti zing fluid F .

[0050] The ozone generation system 20 also comprises an oxygen source 0, such as a pressuri zed cylinder, fluidically connected to the ozone generator 22 , which is configured to receive incoming oxygen from the aforesaid source and generate O3 as described below . The oxygen source 0 can be housed in the space 19 or outside it .

[0051] As may also be seen in figure 3 , advantageously, the ozone generator 22 is supported by a shel f 23 borne by guides 24 , which are fixed to the structure 2 ' ’ , in particular slidably relative to the transverse axis B .

[0052] The ozone generation system 20 is schematically illustrated in figure 4 . Hereinbelow the terms "upstream" and "downstream" make reference to the direction of flow of the fluid in the conduits illustrated .

[0053] The oxygen source 0 is connected downstream to the ozone generator 22 through valve means 25 .

[0054] The ozone generator 22 comprises at least one ozonation tube , 22 ’ 22 ’ ’ , controlled by a high-voltage electric circuit 26 and configured, as is known, to produce ozone from the flow of oxygen coming from aforesaid oxygen source under the action of the high electrical voltage supplied by the electric circuit 26 . In the figure illustrated there are two ozonation tubes 22 ' , 22 ' ’ fluidically connected in series to each other .

[0055] The ozone generator 22 advantageously comprises valve means 27 located fluidically downstream of the ozonation tubes 22 ' , 22 ' ’ and configured to regulate the emission of ozone fluid towards the space 3 .

[0056] The saniti zation system 1 further comprises an electronic unit (not illustrated) electrically connected to the ozone generation system 22 , speci fically to the valve 27 and to the electric circuit 26 , to control the emission of a predefined amount of ozone into the space 3 . The electronic unit is also electrically connected to the ventilation means 10 and to the venting means 12 to control the operation thereof .

[0057] The saniti zation system 1 further comprises selection means 40 , such as a screen, pushbuttons or an app downloadable to a smartphone , configured to enable the operator to select a predefined saniti zation cycle and sensor means 30 configured to detect the amount of ozone circulating in the space 3 .

[0058] The electronic unit is electrically connected to the selection means and to the sensor means 30 and comprises processing means configured to process the data acquired from the selection means and the sensor means 30 and to control the ozone generation system 20 , the ventilation means 10 and the venting means 12 accordingly.

[0059] In particular, the electronic unit is configured to store a plurality of sanitization cycles which may be selected by the user via the selection means. Every sanitization cycle is characterized by the process time, i.e. the length of time for which the recirculation of the sanitizing fluid is maintained in the space 3.

[0060] Preferably, the aforesaid sensor means 30 can be spectrophotometers, preferably UV spectrophotometers.

[0061] By way of example, the ozone generation system 22 is controlled so as to supply an amount of ozone such as to obtain an ozone concentration between 0.5 and 200 ppm at atmospheric pressure and temperatures, i.e., in particular, between 0.8 and 1.0 bar and 10°C and 50°C, respectively. Conveniently, the ozone concentration is constant in the first and second portions 3a, 3b. Conveniently, the maximum difference between the maximum and minimum ozone concentrations between two different points of the first and second portions 3a, 3b is less than 10% of the maximum ozone concentration; advantageously, the ozone concentration is in fact substantially uniform in the first and second portions 3a, 3b.

[0062] In particular, a standard sanitization cycle with a sanitizing fluid at the aforesaid concentration is configured to run for 30 seconds to 60 minutes. The saniti zation system 1 can also be equipped with a lighting system, such as internal LED lights .

[0063] Moreover, the saniti zation system 1 can be equipped with signalling means (not illustrated) such as indicator lights and / or acoustic indicators or icons on a display, configured to visually and / or acoustically signal the execution of a saniti zation cycle . Advantageously, the signalling means can be integrated into the aforesaid selection means 40 by means of a single display .

[0064] The operation of the embodiment of the ozone saniti zation system according to the above-described invention is as follows .

[0065] The user of the saniti zation system 1 can access the space 3 by opening the front wall 2c and loading the elements to be saniti zed on the supporting means 13 , 14 . Once the loading operation is completed, the user can start a saniti zation cycle thanks to the selection means . Accordingly, the electronic unit will control the ozone generation system 20 so as to produce an amount of ozone and reach a predefined concentration, also as a function of the volume of the space 3 . During the delivery of ozone by the ozone generation system 20 , the ventilation means 10 and / or the venting system 12 are activated in order to allow recirculation and the mixing of ozone with the air present in the space 3 , thus generating the saniti zing fluid F, which will pass between the articles to be sanitized. Upon the reaching of the predefined ozone concentration, controlled via the sensor means, the ventilation means 10 and / or the venting system 12 are kept activated for a predefined duration in the previously defined time interval.

[0066] Once that time has elapsed, the ventilation system 10 can be deactivated, the venting system 12 remaining activated to enable the discharge of the sanitizing fluid F to the external environment, until safe conditions have been reached .

[0067] Based on what has been discussed above, the invention also relates to a method of sanitizing a surface, preferably textile materials, for example garments, comprising a step of treating said surface with a sanitizing fluid F consisting of a mixture of air and ozone, wherein the ozone has a concentration between 0.5 and 200 ppm, preferably between 5 and 50 ppm, more preferably between 15 and 25 ppm, for a time between 30 seconds and 60 minutes, preferably between 5 and 15 minutes.

[0068] The method of the invention can be carried out at a temperature between 10 and 50°C and at atmospheric pressure, for example between 0.8 and 1.0 bar absolute.

[0069] In one embodiment, the method of the invention can be used with the sanitization system 1 described above. In particular, the method of the invention applied to the sanitization system 1 comprises the following steps: i. Delivering an amount of sanitizing fluid F consisting of a mixture of air and ozone, wherein the ozone has a concentration between 0.5 and 200 ppm in the space 3 isolated from the external environment . ii. Recirculating the sanitizing fluid F in the space 3 by means of ventilation means 10 - for a time between 30 seconds and 60 minutes.

[0070] Advantageously, step i) further comprises the following sub-steps : i-a) activating an ozone generation system to provide a sanitizing fluid F consisting of a mixture of air and ozone, wherein the ozone has a concentration between 0.5 and 200 ppm in the space 3; i-b) detecting the ozone concentration in said space 3 by means of a built-in sensor; i-c) regulating the ozone production by said ozone generation system 20 in order to maintain said concentration between 0.5 and 200 ppm depending on the concentration detected in step i-b) , and returning to step i-a) .

[0071] The detection in step i-b) can be carried out at predefined time intervals or, better, continuously.

[0072] The above-described method is substantially continuous ( in particular the process is continuous in the case of the gas ; it can instead be discontinuous in the case of the processed material to be sanitized : the material is loaded, the material is saniti zed, the material is unloaded) ; alternatively, a third step can be provided for : iii . activating means for extracting the gas 12 in order to discharge the saniti zing fluid F into the external environment to provide for a discontinuous treatment cycle .

[0073] The aforesaid steps of the method according to the invention are advantageously memori zed in the electronic unit and automatically carried out by the latter .

[0074] Based on the foregoing, the advantages of an ozone saniti zation system and an ozone saniti zation method according to the invention appear evident .

[0075] Thanks to the proposed system it is possible to saniti ze a surface of varying nature , in particular made of a material selected from the group consisting of metals , polymers , paper, tanned products , fabrics , fibres of natural origin, or artificial or synthetic fibres, and glass .

[0076] Advantageously, in the case of fabrics and tanned products , the method of the invention enables an ef fective saniti zation without degrading the colour of the treated surface .

[0077] Furthermore , in the field of fabrics and garments , the properties of the fibres of which they are made remain unchanged in terms of colour and mechanical characteristics .

[0078] The above is obtained by carrying out a total saniti zation of the surfaces , and in particular by eliminating various pathogens , including the SARS-COV-2 virus .

[0079] Moreover, the use of a predefined ozone concentration, which is reduced compared to the known systems , makes it possible to reduce the oxygen costs and electricity consumption of the saniti zation system, with consequent savings .

[0080] Notwithstanding the predefined, controlled and reduced ozone concentration, the saniti zation system allows for a cycle of only a few minutes , enabling a use adapted to various activities .

[0081] Furthermore , the proposed method and system are of a modular type , i . e . scalable as desired, according to the user' s needs .

[0082] Finally, it is clear that modi fications and variants can be introduced to the ozone saniti zation system and ozone saniti zation method according to the present invention without , however, going outside the scope of protection defined by the claims .

[0083] Clearly, the structure , the housing space and the arrangement of elements inside that space can vary according to the requirements of use of the saniti zation system . Moreover, it is clear that the partition wall, the ventilation means, the venting means, or the sensor means can be placed in different positions from what has been described or else be produced in any type.

[0084] Similarly, the oxygen source and the ozone generation system can be provided by means of circuits and systems differing from the ones described.

[0085] Additional features of the present invention will become apparent from the description that follows of some merely illustrative, non-limiting examples.

[0086] MICROBIOLOGICAL LABORATORY TEST ON SANITIZATION AGAINST SARS-COV2 AND OTHER PATHOGENIC AGENTS

[0087] In order to evaluate the effectiveness of the method of the invention for the sanitization of various materials, a protocol was developed to simulate the contamination of various fabrics and other non-textile materials, for example used in the production of clothing articles and accessories, which are then subjected to the sanitization process according to the invention.

[0088] A total of 16 materials were selected for the analysis, of which 12 of a textile nature and 4 of a non-textile nature. The samples, together with the specifications of their composition, are listed in table 1; they will hereinafter be indicated with their identification number.

[0089] Table 1.

[0090] Treatment chamber (chamber 3)

[0091] The treatment chamber is made of stainless steel and has a volume of 30 litres (0.03 m3) . It is provided with a stainless steel rack for positioning samples, with a nominal size of 15 mm x 100 mm. The chamber was continuously flushed with a gaseous atmosphere of air enriched with a mixture of O2 / O3 dosed so as to reach the predetermined compositions . The gas flow rate was regulated, by means of a speci fic regulation panel , at 30 L / min in order to have a gas retention time of 1 minute in the treatment chamber .

[0092] Contamination of the materials and treatment with O3

[0093] The contamination was brought about using a viral suspension obtained by propagation, in a cell culture of Vero E 6 cells (ATCC CRL- 1586 ) , of a residual positive clinical sample from routine activities at the Microbiology Unit of the Laboratory of the Service Centre of the Romagna Local Health Authority in Cesena, Italy . The Sars-CoV-2 viral strain was identi fied as a B . l lineage by Whole-Genome Next- Generation Sequencing ( I llumina ) . The viral strain was titrated using the "endpoint" dilution method and the viral titre , expressed in TCID50 / mL ( Tissue Culture Infectious Dose , unit of measurement of the infectious viral load within a cell culture ) , was calculated with the Reed-Muench formula based on eight replicates per dilution . For the contamination of the materials , the viral isolate was diluted to a working concentration of 105TCID50 / mL . The contamination was brought about by depositing three drops of a 100 pL viral suspension on the surface of the test materials .

[0094] After the contamination, the pieces of material were hung in the treatment chamber of the saniti zation system according to the invention and then subj ected to decontamination with the method according to the invention . Di f ferent ozone concentrations were evaluated; the most signi ficant are shown here below :

[0095] 1 . Test with a preset concentration under the following conditions o Treatment time : 10 minutes o Pressure : atmospheric o Temperature : room o Ef fective O3 Concentration 28 ppm

[0096] 2 . Test with a preset concentration under the following conditions o Treatment time : 10 minutes o Pressure : atmospheric o Temperature : room o Ef fective O3 Concentration 17 ppm

[0097] Both tests were carried out in duplicate .

[0098] After the treatment , all the materials were removed from the chamber , eluted in 2 mL of a cell culture medium with 2 % FBS and agitated in a vortex shaker for 60 seconds to favour the elution of the viral particles (understood as extraction of the viral load from the analysed sample ) . The eluates were then used to infect a confluent monolayer of Vero E 6 cells seeded the day before the infection in 6-well plates at a density of 500 , 000 cells per well in a cell culture medium with 10% FBS . After an hour of incubation the inoculum was removed, the cell monolayers were washed with PBS to remove the debris of material and avoid problems of cellular toxicity and the medium was replaced with 2 mL of culture medium with 2 % BBS . The cell cultures were then incubated at 37 ° C in an incubator with an atmosphere enriched with 5% C02 for 48 hours .

[0099] Simultaneously, to determine the capacity of each material analysed to retain a suf ficient amount of viral suspension after the contamination, the samples were regularly contaminated and placed in a treatment chamber, but were not exposed to O3 . These samples were eluted in a similar manner to the ones treated with O3 and the eluates were used to infect cell cultures ("materials control" ) to evaluate viral replication .

[0100] A further cell culture ( "virus control" ) was directly infected by diluting 300 pL of viral suspension in 2 mL of fresh medium .

[0101] Finally, a further cytotoxicity control was set up - to exclude any potential interference of the toxic activity exerted by the tested materials on the cell cultures and thus on the evaluation of viral replication - by eluting pieces of uncontaminated material and incubating the eluates for an hour in the cultures , then replacing the culture medium with fresh medium with 2 % FBS , as for the contaminated material , decontaminated ("tested materials" ) or not ("materials control") . These cells as well were incubated for 48 hours ("cytotoxicity control") .

[0102] Results - Toxicity

[0103] As regards the toxicity assay, cell viability was quantified after the incubation period; the cell monolayers were fixed and stained using a solution of 4% formaldehyde in crystal violet and the absorbance was read at 595 nm. The results showed that none of the tested materials exerted a toxic effect on the cell culture.

[0104] Quantification of viral load and evaluation of virucidal capacity

[0105] In all cases, the viral load was evaluated by qRT-PCR (quantitative real-time polymerase chain reaction) in the eluates and in cell cultures, both immediately after the addition of fresh medium (referred to as time 0 "TO") and after 48 hours of incubation (referred to as time 48 hours, "T48") . Viral replication was evaluated using the "Allplex SARS-CoV-2 Extraction-free" test (Seegene Inc., Seoul, South Korea) . As regards the capacity of the materials to retain the viral suspension, based on the Ct values (cycle threshold, i.e. amplification cycle of the qRT-PCR process at which the nucleic acid present is detected) obtained from the eluates, a calculation was made of the percentage of virus retained compared to the virus concentration in the virus control culture, set as the highest virus concentration (i.e. 100%) that could possibly be reached in the culture, considering the contamination inoculum (for example, a percentage of 95% in the eluate of the material 2 means that the material 2 has retained 95% of the virus detected in the virus control) . Thirteen of the tested materials maintained a high percentage of the inoculum, ranging between 77% and 100%, whereas for others the concentration was considerably lower (table 2) . In any case, this concentration was nonetheless sufficient to enable cell infection: at time TO after infection, all the cultures tested positive for SARS- CoV-2, with the exception of material 13, for which no genetic material was detected. At TO, the virus concentration in the "control materials" was compared to the virus concentration in the "virus control" and expressed as a percentage, once again, setting the concentration detected in the "virus control" as the highest possible concentration (100%) considering the volume of inoculum, so as to be able to express, for every material considered, the actual virus concentration capable of infecting the cultures compared to the "virus control".

[0106] Irrespective of the concentration detected at the start of incubation, for all the cultures of the "control materials" the viral load after 48 hours (T48) was comparable to the "virus control". The viral concentrations in the eluates, and in the cell culture, both at "TO" and "T48", in the "control materials" expressed as a percentage of the concentration detected in the "virus control" sample , are shown in table 2 . Material 13 is the only material for which, based on the qRT-PCR analysis , no genetic material attributable to SARS-CoV-2 was detected at TO ( 0% versus the virus control ) , being present in concentrations below the detection limit of the molecular test used . Subsequently, the amount of virus capable of infecting the culture , though exiguous , nonetheless allowed viral replication, which became evident after 48 hours of incubation ( 100% versus the virus control ) . A possible interpretation of the results obtained, which arises considering the structure of the leather matrix, is that the virus is adsorbed by the structure itsel f , making it di f ficult to elute / extract it from the material after the contamination thereof , and thus making a reduced amount of virus available for cell infection .

[0107] Table 2 - Evaluation of the capacity of the tested materials to retain the virus

[0108] As previously described, the virus concentration present in the eluate expresses the amount of virus extracted from the material by means of immersion of the contaminated material in 2 mL of culture medium and 60 seconds of treatment in a vortex shaker . The concentration at "TO" , by contrast , is the amount of virus that remains in the culture after the infection of the latter with the eluate , one hour of incubation, washing with PBS and the addition of new culture medium .

[0109] Once the ef fectiveness of the contamination procedure had been demonstrated, the virucidal capacity of saniti zation with O3 was evaluated by calculating the percentage of inhibition of viral replication compared to the corresponding "material control" . First , the virucidal ef fect was evaluated immediately after saniti zation by comparing the concentration of the virus recovered from the elution of the treated materials and the control materials . The persistence o f the virus after saniti zation was expressed as a percentage for each material , setting the concentration of the virus recovered from the corresponding "material control" , not subj ected to saniti zation, at 100% . These data show a substantial reduction in the viral genetic material after saniti zation, which is inversely proportional to the concentration of O3 used ( the higher the concentration of O3, the lower the viral concentration, compared to the untreated material ) . For some materials ( 5 , 6 , 12 and 13 ) , no viral genetic material was detected in the eluates after saniti zation ( 0% persistence of the virus ) . All these results suggest a direct ef fect of O3 in disintegrating the virus genome and thus in reducing infectivity, making the portion of genetic material detected following the treatment with ozone , presumably attributable to viral particles that are no longer infectious . The results are illustrated in Table 3 .

[0110] Table 3 - Evaluation of the decontamination ef fectiveness and direct action of O3 on the genetic material of SARS-CoV-2

[0111] In Table 3 , the comparison was made individually for every material with the respective control material ( set at 100% ) , in order to assess the result regarding replication in relation to the actual capacity of that material to retain the solution used for contamination and thus to the actual amount of virus present on the individual materials , so there does not exist a single reference "material control" ( e . g . a percentage of 27 % for material 1 at 17 ppm means that the virus concentration in the eluate of material 1 after treatment corresponds to 27 % of the concentration detected in the corresponding control for material 1 ) .

[0112] As confirmation, immediately after the removal of the inoculum and replacement of the medium at TO , no viral genetic material was detected for any of the materials considered under either of the test conditions , supporting the assumption of a total loss of infectivity after exposure to O3 : at TO , for all the materials , it was not possible to detect viral genetic material by qRT-PCR, so for all materials the result of the test is N / A (not ampli f ied) , as shown in Table 4 . The viral replication capacity was further evaluated by culturing the eluates in cell cultures , as previously described . The results of qRT-PCR with respect to TO and T48 hours of culture are shown in Table 4 below . Table 4 . Results of qRT-PCR analysis

[0113] The analysis as per Table 4 was performed for every single material at TO ( immediately after the addition of new culture medium) and at T48 ( after 48 hours of incubation) . The results are shown separately for the two tested concentrations of O3 (N / A means not ampli fied, i . e . no viral genetic material was detected within the reaction) .

[0114] For all the materials considered, no viral replication was detected at any tested concentration of O3 ( the result of the test was N / A for all the materials ) , thus demonstrating a complete ef fectiveness of saniti zation against SARS-CoV-2 after treatment with O3 at concentrations of 17 and 28 ppm .

[0115] COLORIMETRIC & STRUCTURAL ANALYTIC LABORATORY TESTS . Both evaluations were carried out following the same sanitization process as used during the tests conducted in the microbiology laboratory, with 6 treatment cycles lasting 10 minutes each for a total of 60 minutes (indicated below as "cumulative time") per sample undergoing analysis.

[0116] Both tests were carried out with the same sanitization process as used during the tests in the microbiology laboratory, with 6 treatment cycles lasting 10 minutes each for a total of 60 minutes per sample undergoing analysis.

[0117] Colorimetric Measurement

[0118] In order to demonstrate that the method according to the invention does not compromise the quality of the product from either a colour or structural standpoint, the samples were subjected to a number of treatment cycles.

[0119] In particular, each sample was subjected to 6 treatment cycles, after which colorimetric tests were carried out using DATACOLOR 550, proceeding according to ISO standards (ISO 105- J01 : 1997, Textiles — Tests for colour fastness — Part J01: General principles for measurement of surface colour (1997) ; ISO 105- JOS : 2009, Textiles — Tests for colour fastness — Part JOS: Calculation of colour differences (2009) ) .

[0120] The analytic method provides for a colorimetric analysis of the samples before treatment (untreated sample) and after treatment (treated sample) in order to evaluate the possible differences caused by the ozone oxidation reaction. The fabric samples were measured directly, whereas the yarn / thread samples were wrapped over rigid cardboard with the aim of arranging the fibres parallel and creating a uniform surface.

[0121] Every sample was instrumentally measured in 6 different points and the final colorimetric characteristics were calculated as an average of 6 measurements in order to attenuate any lack of uniformity in colour as much as possible .

[0122] The colorimetric characteristics were measured with a reflectance spectrophotometer according to the standards of the GTE (Commission Internationale de 1 ' Eclairage ) , i.e. using the CIELAB coordinates (L=lightness, a=green-red coordinate, b=blue-yellow coordinate) , using the standard illuminant D65 and 10° geometry.

[0123] Based on the difference between the colorimetric characteristics of the sample before treatment and after treatment, it was possible to calculate the Total Colour Difference, i.e. the CIE DE, by means of the formula:

[0124] DE = ("DL2 + Da2 + Db2") where :

[0125] DE = total colour difference between the sample before and after treatment.

[0126] DL = difference in lightness between the sample before and after treatment.

[0127] Da difference in red and green colour between the sample before and after the treatment.

[0128] Db = difference in yellow and blue colour between the sample before and after treatment.

[0129] The untreated sample was further measured with statistical methods to obtain a value of DE that is indicative of the intrinsic uniformity of the starting s amp les.

[0130] For some fabric samples, the measurements were performed on both sides, as they were characterised by differently structured fronts and backs.

[0131] The tolerance limit value was set equal to DE = 1.00; below this value, the differences in colour between the sample and reference standard are deemed not critically significant .

[0132] This tolerance value was chosen since, in sectors such as textiles and graphic arts, it represents the just noticeable difference (JND) , i.e. the value below which the colorimetric differences between two objects are nearly imperceptible to the human eye, as confirmed by the scientific literature ("Colour Engineering: Achieving Device Independent Colour" - Edited by Phil Green & Lindsay MacDonald. Wiley; "The Reproduction of Colour" - R.W.G. Hunt, Wiley; "Color Science: Concepts and Methods, Quantitative Data and Formulae" - Gunther Wyszecki & WS Stiles. Wiley) , manufacturers of measuring instruments and industrial practice .

[0133] Any deviations from the tolerance limit are analysed case by case.

[0134] The ozonization tests were conducted at progressively higher ozone concentrations (up to a maximum of 50 ppm) , each time analysing differences in colour between the treated and untreated samples and proceeding to a test at a higher concentration in the event of positive colorimetric results.

[0135] Structural Measurements

[0136] In order to evaluate a potential effect of the ozone on the mechanical properties of fabrics and yarns, a selection thereof was subjected, after having been treated with the method of the invention, to tensile tests by means of a dualcolumn dynamometer.

[0137] In order to evaluate the mechanical properties of fabrics and yarns, use was made of a Gester GT-C01-1C dualcolumn dynamometer, proceeding according to ISO standards regarding fabrics [ISO 13934-1:2013] and yarns [ISO 2062 : 2009] .

[0138] For every fabric / yarn sample, a reference standard was identified, corresponding to a fabric / yarn sample as such, i.e. which was not subjected to treatments with ozone, with respect to which the differences in mechanical properties were calculated.

[0139] For these analyses, an inverse procedure compared to the colorimetric evaluations was adopted; the most severe treatment conditions (50 ppm) were tested first and then reduced in the event of a variation in performance exceeding the tolerance limit, which, based on indications coming from industrial practice, was set at a 5% variation in f orce / elongation compared to the control.

[0140] Regulations prescribe the performance of tensile tests on single yarns, provided that 50 replications of the same yarn sample are included. Regulations provide for 20 tests on every yarn sample composed of 50 yarns, if single, and 20 yarns, if plied.

[0141] Tests were performed on yarns of a length equal to 250 mm, to which another 200 mm were added (100 mm per side) , corresponding to the length of yarn gripped by the two clamps of the dynamometer, for a total of 450 mm.

[0142] For every yarn sample, a reference standard was identified, corresponding to a yarn sample as such, i.e. which was not subjected to treatments with ozone, with respect to which the differences in mechanical properties were calculated.

[0143] RESULTS OF COLORIMETRIC TESTS

[0144] All tests were conducted using the product D65, 10 degrees, as the illuminant. Reference and sample composition: orthogonal fabric, 100%

[0145] POLYESTER

[0146] *"cumulative time" of treatment

[0147] Comments :

[0148] The 100% POLYESTER sample does not show differences between front and back.

[0149] The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, untreated) .

[0150] Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Given an equal number of treatment cycles, up to a total of 60 min, the sequence of treatments, at progressively larger ppm of ozone, does not show an upward trend in DE, but rather a fluctuation in the latter.

[0151] Reference and sample composition: 100% SILK *"cumulative time" of treatment

[0152] *"cumulative time" of treatment

[0153] Comments :

[0154] The 100% S ILK sample has a front and back that are nearly identical . The variability within every face of the fabric sample is evident from the average values of CIE DE ( out of 6 measurements ) of the reference standard ( sample as such, front and back, untreated) .

[0155] Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Given an equal treatment time (60 min) , the sequence of treatments, at progressively larger ppm of ozone, does not show an upward trend in DE but rather a fluctuation in the latter.

[0156] Reference and sample composition: 100% COMBED WOOL

[0157] 10

[0158] *"cumulative time" of treatment

[0159] Comments :

[0160] The 100% COMBED WOOL sample does not show differences between front and back. The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, untreated) .

[0161] Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Reference and sample composition : knitted fabric 98%

[0162] CASHMERE / 2% LYCRA *"cumulative time" of treatment

[0163] *"cumulative time" of treatment

[0164] Comments : The 98% CASHMERE / 2% LYCRA sample has a front and a back; however, they do not show significant differences from a colorimetric standpoint.

[0165] The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, front and back, untreated) .

[0166] Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Given an equal treatment time (60 min) , the sequence of treatments, at progressively larger ppm of ozone, does not show an upward trend in DE but rather a fluctuation in the latter.

[0167] Reference and sample composition: orthogonal fabric, 80%

[0168] POLYAMIDE / 20% ELASTANE

[0169] *"cumulative time" of treatment

[0170] *"cumulative time" of treatment

[0171] Comments :

[0172] The 80% POLYAMIDE / 20% ELASTANE sample has a front and a back; however, they do not show significant differences from a colorimetric standpoint.

[0173] The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, front and back, untreated) .

[0174] Possible anomalous sample (front side) in the test at 22 ppm (inlet) . The sample, in fact, was rejected in the test at 60 min and at the limit of tolerance in the ozonization test at 50 min. However, the tests performed at higher ozone concentrations (35 and 45 ppm) , likewise at 60 min of treatment, did not show the same result, but rather better results perfectly within the range of tolerance.

[0175] Overall, all the other samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Reference and sample composition: orthogonal fabric, 91%

[0176] COMBED WOOL / 8% POLYAMIDE / 1% ELASTANE

[0177] 5

[0178] *"cumulative time" of treatment *"cumulative time" of treatment

[0179] Comments :

[0180] The 91% COMBED WOOL / 8% POLYAMIDE / 1% ELASTANE sample has a front and a back; however, they do not show significant differences from a colorimetric standpoint. The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, front and back, untreated) . Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Given an equal treatment time (60 min) , the sequence of treatments, at progressively larger ppm of ozone, does not show an upward trend in DE but rather a fluctuation in the latter. Reference and sample composition: orthogonal fabric, 100%

[0181] COTTON

[0182] *"cumulative time" of treatment

[0183] Comments :

[0184] The 100% COTTON sample has a front and a back; however, they do not show significant differences from a colorimetric standpoint . The variability within every face of the fabric sample is evident from the average values of CIE DE ( out of 6 measurements ) of the reference standard ( sample as such, untreated) . Overall , the samples fall within the ranges of tolerance versus the reference standard ( CIE DE < 1 ) .

[0185] Reference and sample composition : orthogonal fabric , 100%

[0186] VISCOSE

[0187] *"cumulative time" of treatment

[0188] Comments :

[0189] The 100% VISCOSE sample has a front and a back; however, they do not show signi ficant dif ferences from a colorimetric standpoint .

[0190] The variability within every face of the fabric sample is evident from the average values of CIE DE ( out of 6 measurements) of the reference standard (sample as such, untreated) .

[0191] Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Reference and sample composition: orthogonal fabric, 100%

[0192] LINEN *"cumulative time" of treatment

[0193] Comments :

[0194] The 100% LINEN sample has a front and a back; however, they do not show significant differences from a colorimetric standpoint . The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, untreated) . Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) .

[0195] Reference and sample composition: orthogonal fabric 100%

[0196] HEMP

[0197] *"cumulative time" of treatment

[0198] Comments : The 100% HEMP sample has a front and a back; however, they do not show significant differences from a colorimetric standpoint .

[0199] The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, untreated) .

[0200] Overall, the samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) . Reference and sample composition : orthogonal fabric , 100%

[0201] CARDED WOOL

[0202] *"cumulative time" of treatment

[0203] Comments :

[0204] The 100% CARDED WOOL sample has a front and a back; however, they do not show signi ficant dif ferences from a colorimetric standpoint .

[0205] The variability within every face of the fabric sample is evident from the average values of CIE DE ( out of 6 measurements ) of the reference standard ( sample as such, untreated) . Overall , the samples fall within the ranges of tolerance versus the reference standard ( CIE DE < 1 ) .

[0206] Reference and sample composition : 100% LEATHER (CALFSKIN)

[0207] *"cumulative time" of treatment Comments :

[0208] The 100% LEATHER ( CALFSKIN) sample has a front and a back; however, only the front was analysed, being the side in view . The variability within every face of the fabric sample is evident from the average values of CIE DE ( out of 6 measurements ) of the reference standard ( sample as such, untreated) .

[0209] Overall , the samples fall within the ranges of tolerance versus the reference standard ( CIE DE < 1 ) .

[0210] Reference and sample composition : orthogonal fabric , POLYURETHANE (front side) / COMBED WOOL (back side)

[0211] *"cumulative time" of treatment

[0212] Comment : The analysed sample has, on the front side, a polyurethane surface that is very irregular from the viewpoint of colour uniformity. This is demonstrated by the presence of a DE = 0.59 on the front of the untreated sample.

[0213] Therefore, obtaining a CIE DE < 1 (in absolute value) under the various treatment conditions is plausible; however, it is always necessary to compare the values with the CIE DE of the starting sample in order to obtain the relevant values.

[0214] *"cumulative time" of treatment

[0215] Comments :

[0216] The POLYURETHANE (front side) / COMBED WOOL (back side) sample has a front and a back which are completely different. The variability within every face of the fabric sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, front and back, untreated) .

[0217] As previously noted, the front, made up of polyurethane, has an irregular surface from a colorimetric standpoint; therefore, it is always necessary to compare the values of CIE DE of the treated samples with the CIE DE of the starting sample in order to obtain the relevant values.

[0218] The back, consisting of combed wool, instead has an extremely uniform surface and, overall, the treated samples fall within the ranges of tolerance versus the reference standard (CIE DE < 1) .

[0219] Reference sample: PAPER

[0220] *"cumulative time" of treatment

[0221] Comments :

[0222] The PAPER sample appears extremely uni form on both faces , from both a visual and colorimetric standpoint .

[0223] This fact is demonstrated by the measurements of sample variability and evident from the average values of CIE DE ( out of 6 measurements ) of the reference standard ( sample as such, untreated) . The average DE as regards the measurements performed over the whole sample is very low, a sign that the sample appears extremely homogeneous .

[0224] The samples were tested at an ozone concentration of 50 ppm and for treatment times of 50 and 60 min, respectively . The results of the colorimetric analys is show a very low CIE DE in both cases and, overall , both measured samples fall well within the range of tolerance versus the reference standard ( CIE DE < 1 ) , a sign that the treatment with ozone under the previously indicated conditions did not influence the colour of the material .

[0225] Reference sample : PLASTIC (POLYMERIC FILM)

[0226] *"cumulative time" of treatment Comments :

[0227] The PLASTIC ( POLYMERIC FILM) sample appears extremely uni form on both faces , from both a visual and colorimetric standpoint .

[0228] This fact is demonstrated by the measurements of sample variability and evident from the average values of CIE DE ( out of 6 measurements ) of the reference standard ( sample as such, untreated) . The average DE as regards the measurements performed over the whole sample is very low, a sign that the sample appears extremely homogeneous . The samples were tested at an ozone concentration o f 50 ppm and for treatment times of 50 and 60 min, respectively . The results of the colorimetric analys is show a modest CIE DE in both cases and, overall , both measured samples fall within the range of tolerance versus the reference standard (CIE DE < 1) , a sign that the treatment with ozone under the previously indicated conditions has a negligible influence on the colour of the material. Reference and sample composition: multi-filament continuous thread, 100% KEVLAR *"cumulative time" of treatment

[0229] Comments :

[0230] The 100% KEVLAR multi-filament thread sample has uniform colorimetric characteristics in terms of hue.

[0231] The variability within the yarn sample is evident from the average values of CIE DE (out of 6 measurements) of the reference standard (sample as such, untreated) .

[0232] Overall, the treated sample is within the range of tolerance versus the reference standard (CIE DE < 1) .

[0233] Reference and sample composition: yarn, 100% ACRYLIC

[0234] *"cumulative time" of treatment

[0235] Comments :

[0236] The 100% ACRYLIC yarn sample has uni form colorimetric characteristics in terms of hue .

[0237] The variability within the yarn sample is evident from the average values of CIE DE ( out of 6 measurements ) of the reference standard ( sample as such, untreated) .

[0238] Overall , the treated sample is within the range of tolerance versus the reference standard ( CIE DE < 1 ) .

[0239] RESULTS OF MECHANICAL TESTS

[0240] In order to evaluate the possible degrading ef fects of ozone , a test was performed on a sample made of 100% leather to evaluate the mechanical properties after treatment .

[0241] The sample was subj ected to 6 continuous cycles of 10 minutes each at 1-minute intervals and subsequently analysed by means of dynamometric tests .

[0242] In particular, the total ozoni zation treatment in the chamber was 60 min long, but with 10 min treatment cycles , where the treatment was interrupted at the end of the 10 min and resumed only after the chamber had been opened and aired out for 1 min .

[0243] In the dynamometric tests the sample , of a standard si ze and number, was secured, at the two opposite ends , to the clamps of a dynamometer which applied a constant pulling speed and provided the results both in numerical form and with loadelongation curves of the sample up to the breaking point .

[0244] In order to enable an immediate evaluation of the di f ferences between the mechanical properties of the sample as such ( original , untreated) and the treated sample , a table is provided below showing the average values of peak force associated with the percentage elongation at break, and the respective percentage di f ferences .

[0245] Legend :

[0246] OR = original

[0247] TR = treated after 60 min at 50 ppm of O3 The values shown are the average values of the three measurements made.

[0248] It can be noted that in the passage between the original (OR) and treated (TR) samples, there is a much more marked increase in the breaking force.

[0249] RESULTS OF MECHANICAL TESTS - YARNS

[0250] The selection of yarns / threads to be subjected to an ozonization treatment and subsequent dynamometric tests is the following:

[0251] - Yarn 100% SILK, titre Nm 1 / 30

[0252] - Yarn 100% VISCOSE, titre Nm 1 / 8

[0253] - Yarn 100% HEMP, titre 1 / 36

[0254] - Yarn 80% NYLON / 20% COMBED WOOL, titre Nm 2 / 30

[0255] - Yarn 100% CARDED WOOL, titre Nm 4 / 16

[0256] - 100% ACRYLIC

[0257] - 85% COTTON / 15 SILK

[0258] - 100% JUTE

[0259] - 100% KEVLAR

[0260] - 100% COMBED WOOL

[0261] - 100% LINEN

[0262] - 100% POLYESTER

[0263] The fabric samples were subjected to ozonization tests, ozone for 60 min, and subsequently analysed by means of dynamometric tests. The overall ozoni zation treatment of the samples in the chamber was 60 min long, but with 10 min treatment cycles , where the treatment was interrupted at the end of the 10 min and resumed only after the chamber had been opened and aired out for 1 min .

[0264] In the dynamometric tests the yarn samples , of a standard si ze and number, were secured, at the two opposite ends , to the clamps of a dynamometer which applied a constant pulling speed and provided the results both in numerical form and with load-elongation curves of the sample up to the breaking point .

[0265] In order to enable an immediate evaluation of the di f ferences between the mechanical properties of the sample as such ( original , untreated) and the treated samples , a table is provided below showing every type of material associated with the average values of peak force , peak elongation, percentage elongation at peak load and percentage elongation at break, and the respective percentage di f ferences .

[0266] Legend :

[0267] OR = original

[0268] TR = treated after 60 min at 50 ppm of O3

[0269] Legend :

[0270] OR = original

[0271] TR = treated after 60 min at 31 ppm of O3 Legend :

[0272] OR = original

[0273] TR = treated after 60 min a 30 ppm of 03 The results presented above demonstrate that treatments on dyed fabrics performed with ozone in a gaseous phase at low ozone concentrations ( 30 ppm) influence neither the colorimetric characteristics , i . e . the solidity of the colour, nor the mechanical properties of the same fabrics .

[0274] As regards the colorimetric characteristics , the study demonstrated the importance of performing more than one measurement on the fabric in order to reconcile as much as possible the intrinsic variability in every sample due to a lack of dyeing uni formity, especial ly in the case of fabrics that are not unicoloured .

[0275] An increase in the ozone concentration from 30 to 50 ppm does not influence the degradation of the colour in the treatment times considered in this study .

[0276] Similarly, given the same ppm of ozone , an increase in the treatment time from 10 to 60 min does not result in an increase in the CIE DE versus the reference standard ( sample as such, untreated) .

[0277] As regards the mechanical properties and the inf luence of ozone on them, for the materials considered no signi ficant variations were shown remaining at concentrations of 30 ppm for a maximum of 6 cycles of 10 min each ( total 60 min of treatment ) .

[0278] The di f ficulties tied to the obtainment of obj ective results for fabric samples having intrinsically di f ferent properties ( composition, yarn type , fabric type and weave , finish applied) were overcome by analysing the materials in the form of yarn .

[0279] The analysis of the yarns did not show signi ficant di f ferences for the samples treated at 30 ppm and the percentages of variation detected compared to the yarns as such (untreated) fell within a range of tolerability normally accepted in industrial practice .

Claims

CLAIMS1. - Method of sanitizing a surface comprising a step of treating said surface with a sanitizing fluid (F) consisting of a mixture of air and ozone, in which the ozone has a concentration between 0.5 and 200 ppm, for a time between 30 seconds and 60 minutes.2.- Method according to claim 1, characterized in that said ozone has a concentration between 5 and 50 ppm.3.- Method according to claim 1, characterized in that said step of treating said surface is carried out for a time interval between 5 and 15 minutes.4.- Method according to any of the preceding claims, characterized by being carried out at a temperature between 10 and 50°C and a pressure between 0.8 and 1.0 bar absolute.5.- Method according to any of the preceding claims, characterized in that said surface is made of a material selected from the group consisting of metals, polymers, paper materials, tanned products, textiles, fibres and glass.6.- Sanitization system (1) comprising a structure (2) comprising a plurality of walls (2a, 2b, 2c, 2e) connected together to delimit a space (3) isolated from the external environment, said sanitization system (1) comprising:- an ozone generation system (20) configured to deliver a predetermined amount of ozone into said space (3) ;- ventilation means (10) configured to mix said predeterminedamount of ozone with the air contained in said space (3) ;- sensor means configured to detect the ozone concentration in the space ( 3 ) ;- selection means configured to allow an operator of said sanitization system (1) to choose a predefined sanitization cycle ;- an electronic unit electrically connected to said ozone generation system (20) , said ventilation means (10) , said sensor means and said selection means; said electronic unit comprising processing means configured to process the data acquired from said selection means and said sensor means and to control, accordingly, the operation of said ozone generation system (20) and said ventilation means (10) to generate a sanitizing fluid (F) and sanitize a surface of an element housed in said space (3) , wherein the ozone has a concentration between 0.5 and 200 ppm, and to circulate said sanitizing fluid (F) in said space (3) for a time between 1 and 60 min.7.- System according to claim 6, further comprising venting means (12) configured to selectively allow fluidic communication between said space (3) and said external environment, electronically connected to said electronic unit to selectively allow the discharge of the fluid (F) to the external environment.8.- System according to claim 6 or 7, wherein saidstructure (2) defines a housing portion (2' ' ) adjacent to one of said walls (2e) and defining a housing space (19) separated from said space (3) and configured to house said ozone generation system (20) , said ozone generation system (20) being fluidically connected to said space (3) to allow the delivery of said ozone.9.- System according to one of claims 6 to 8, wherein said sensor means includes a UV spectrophotometer.

10. - System according to any one of claims 7 to 9, wherein said structure (2) comprises a partition wall (2d) and a rear wall (2) housed in said space (3) and configured to subdivide said space into a first, a second and a third portion (3a, 3b, 3c) fluidically connected to each other, the ventilation means (10) being configured to introduce said fluid (F) into one of the portions (3a, 3b) from said third portion (3c) fluidically connected to the ozone generation system (20) , the other of said portions (3a, 3b) being fluidically connected through an aeration grid to the third portion (3c) , thus defining a circulation flow for the fluid (F) between said third portion (3c) and said two portions (3a, 3b) .11.- System according to one of claims 7 to 10, including supporting means (13, 14) configured to support said elements.12.- System according to any one of claims 7 to 11,wherein said ozone generation system (20) comprises an ozone generator (22) provided with at least one ozonation tube (22', 22' ' ) and an electric circuit (26) configured to control its operation, said at least one ozonation tube (22', 22' ' ) being fluidically connected to an oxygen source (0) and being configured to produce ozone from oxygen under the action of said electric circuit (26) .13.- System according to claim 12, wherein said oxygen (0) source comprises a pressurized oxygen tank or a generator of oxygen from air in the external environment, said oxygen (0) source being housed inside or outside the housing space (19) .14.- System according to one of claims 7 to 13, wherein said predetermined amount of ozone is between 1 and 9 g / m3hour15.- System according to one of claims 7 to 14, wherein said predetermined amount of ozone is between 1 and 4 g / m3hour .16.- System according to one of claims 7 to 15, wherein said structure (2) is selectively movable with respect to the ground.17.- System according to any of claims 7 to 16, wherein said structure (2) includes lighting means for said space (3) .18.- Method of sanitizing the surface of an element bymeans of a sanitization system (1) according to claims 6 to 17, comprising the steps of: i. Delivering an amount of sanitizing fluid (F) consisting of a mixture of air and ozone, wherein the ozone has a concentration between 0.5 and 200 ppm in said space (3) isolated from the external environment; and ii. Recirculating said sanitizing fluid (F) in the space(3) by means of ventilation devices (10) in a time between 30 seconds and 60 minutes.

19. Method according to claim 18, wherein said delivering step (i) comprises the sub-steps:(i-a) activating an ozone generation system to provide a sanitizing fluid (F) consisting of a mixture of air and ozone, wherein the ozone has a concentration between 0.5 and 200 ppm in the space (3) ;(i-b) detecting the ozone concentration in said space (3) by means of a built-in sensor;(i-c) regulating the ozone production by said ozone generation system (20) to maintain said concentration between 0.5 and 200 ppm depending on the concentration detected in step i-b) , and returning to step i-a) .

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