FR2972357A1 - Method for disinfection of e.g. space by air, involves spraying heated disinfectant solution to obtain disinfectant solution concentration at constant level in air, where solution comprises peroxygen acid and/or hydrogen peroxide - Google Patents

Abstract

The method involves providing a disinfecting solution, and heating the disinfectant solution at a temperature of 55 degrees Celsius. The heated disinfectant solution is sprayed to obtain disinfectant solution concentration at a constant level in the air in a space e.g. operation theater, where the disinfectant solution comprises a peroxygen acid and/or hydrogen peroxide. A compressing device (55) is utilized for production of compressed air. An independent claim is also included for a device for spraying a liquid.

Description

The invention relates to a method of disinfection by air and a device for carrying out this method. The invention relates more particularly to the disinfection of premises by air. It is known that infectious agents, such as bacteria, viruses, and fungi, are suspended in the air, but also present on the objects and walls of a room. Infectious agents suspended in the air can settle on objects and walls of the room and those already present on the objects and walls can be suspended again in the atmosphere. In the context of the disinfection of premises requiring a very high level of disinfection, such as operating theaters or clean rooms, it is therefore crucial not only to disinfect the objects and the floor of the room, but also the side walls as well as the inactivate infectious agents suspended in the air. Aerial disinfection processes are known for this purpose, using hydrogen peroxide either in the form of a micro-mist or in gaseous form. The use of gaseous hydrogen peroxide has several disadvantages.

The activity of hydrogen peroxide in gaseous form requires complex, expensive and bulky installations which limit the use. For example, it is necessary to reduce the initial hygrometry so as not to disturb the diffusion of the gas and consequently efficiency. As regards the implementation of a micro-mist of hydrogen peroxide, it allows in principle both disinfect walls and objects present in a room. However, disinfection times with this method are quite long, of the order of hours, and the spectrum of antimicrobial activity is usually narrow or incomplete. The lack of activity of these methods vis-à-vis yeasts, molds and certain strains of Staphylococcus aureus is known.

In view of the foregoing an object of the present invention is to provide a method of disinfection by air for effective disinfection in a short time. The Applicant Company has now discovered after long and intense research that the disinfection time could be considerably reduced when the disinfectant solution was heated to a predetermined temperature and sprayed so as to obtain at the end of this spray a concentration of disinfectant solution in the predetermined air.

The invention therefore relates to a method of disinfection, including a room, by air comprising the following steps: provision of a disinfectant solution, heating the disinfectant solution at a temperature of 40 to 65 ° C, creation of a micro-mist by spraying the disinfectant solution heated so as to obtain, at the end of the spraying, a concentration in disinfecting solution in the predetermined air, the disinfecting solution comprising a peroxygenic acid and / or hydrogen peroxide . For the purposes of the present invention, "local" means a room in a building. As non-limiting examples, mention may be made of operating theaters, clean rooms, laboratories and hospital rooms. The invention also relates to a device for spraying a liquid contained in a tank, comprising: - pumping means for withdrawing the liquid in the tank, - heating and regulating means for maintaining the temperature of the liquid taken from a predetermined temperature range, - means for spraying the heated liquid, comprising at least one spray nozzle.

The invention will be better understood on reading the following description accompanied by the appended figures, in which: FIG. 1 is a perspective view of a spraying device according to the invention according to one embodiment. - Figure 2 is a detailed view of the device of Figure 1, more particularly illustrating said heating and control means. - Figure 3 is a detail view of the device of Figure 1, more particularly illustrating said means for spraying the heated liquid. FIG. 4 is a diagrammatic sectional view illustrating the operation of said means for spraying the heated liquid. Also the invention relates to a method of disinfection by air comprising the steps of: providing a disinfectant solution, heating the disinfectant solution at a temperature of 40 to 65 ° C, spraying the disinfectant solution heated so to obtain, at the end of the spraying, a concentration in disinfecting solution in the predetermined air, the disinfecting solution comprising a peroxygenated acid and / or hydrogen peroxide. The disinfecting solution may advantageously be heated to a temperature of 50 to 60 ° C, preferably at about 55 ° C. In one embodiment, the concentration of disinfecting solution in the air, at the end of the spraying, is 5 to 9 mL / m 3, preferably 6 to 8 mL / m 3 and more preferably about 7 mL / m 3. m3. In these conditions, the disinfection time is considerably reduced compared to a process without preheating the disinfectant solution and without obtaining a predetermined concentration of disinfectant solution in the air at the end of the spraying.

The disinfecting solution comprising a peroxygenic acid and / or hydrogen peroxide is preferably an aqueous solution. In one embodiment, the peroxygenated acid is peracetic acid. In this embodiment, the disinfecting solution thus comprises peracetic acid and / or hydrogen peroxide. Preferably, it contains peracetic acid and hydrogen peroxide. The concentration of peroxygenated acid is advantageously from 500 ppm to 5000 ppm by weight relative to the total weight of the aqueous solution, preferably from 700 ppm to 3500 ppm, more preferably from 1000 ppm to 3000 ppm by weight relative to the total weight. disinfectant solution. The concentration of hydrogen peroxide is advantageously from 0.5% to 10%, preferably from 1% to 8% and even more preferably from 1.5% to 7% by weight relative to the total weight of the disinfecting solution.

The disinfecting solution may further comprise a carboxylic acid. The carboxylic acid is advantageously selected from the group consisting of acetic acid, lactic acid, citric acid, sulfamic acid and methanesulfonic acid, with acetic acid being preferred. The carboxylic acid concentration, when present, is 1% to 6%, preferably 2% to 5%, and more preferably 2.50% to 4.50% by weight based on the total weight of the solution. disinfectant. Very good results are obtained when the disinfecting solution, preferably aqueous, contains a peroxygenic acid, in particular peracetic acid, a carboxylic acid, especially acetic acid, and hydrogen peroxide in the concentrations indicated below. above. In a particularly preferred embodiment, the disinfecting solution as defined above is heated to a temperature of about 55 ° C before spraying and the concentration of disinfectant solution in the air is, at the end of the spraying, about 7 mL / m3. Advantageously, use a disinfecting solution, preferably aqueous, comprising peracetic acid and hydrogen peroxide, optionally in combination with acetic acid in the concentrations indicated above. The method of the invention as described above makes it possible to reach a high level of disinfection that satisfies the standard NF T 72 281 version 2009 in a short time. It allows in particular to reach this level of disinfection in less than 150 min. Another object of the invention is to provide a device for spraying a liquid for carrying out the method according to the invention. The invention also relates to a device 1 for spraying a liquid 10 contained in a tank 2, comprising: - pumping means 3 for withdrawing the liquid in the tank 2, - means 4 for heating and regulating to maintain the temperature of the liquid taken from a predetermined temperature range; means 5 for spraying the heated liquid, comprising at least one spray nozzle 50. Said determined temperature range may be between 40 ° C and 65 ° C, preferably between 50 ° C and 60 ° C. For example, said heating and regulating means make it possible to maintain the temperature of the sampled liquid at a constant temperature such that 55 ° C. (+/- 1 ° C.) According to one embodiment, said means 5 for spraying the heated liquid comprise in addition to the spray nozzle 50, a compressed air supply 51 for propelling said heated liquid in admixture with said compressed air. According to one embodiment, said means 5 for spraying the heated liquid comprise a pressure regulating system 52, comprising: a venturi 53 controlled by said compressed air, the vacuum created by the air in the venturi making it possible to suck a liquid at a given flow rate, greater than the flow rate of the pumping means 3, the difference between said determined flow rate and the flow rate of the pumping means producing an air suction, by venturi effect, mixed with said heated liquid, - a circuit venting 54 allowing said air suction. Said venting circuit 54 allows venturi operation of the nozzle and detection of any plugging of the nozzle. The purpose of the venting circuit 54 is to prevent the venturi 53 from being fed with heated liquid under the pressure generated by said pumping means 3, by eliminating the pumping pressure at the fluid inlet 62 of said venturi 53. For example, the pumping means, in particular the peristaltic pump, make it possible to obtain a constant flow rate, for example 17 ml / min. The effect produced by the venturi 53 would make it possible to obtain a heated liquid flow rate higher than that of the pumping means 3, for example 25 ml / min. Possibly a product presence sensor is arranged on the venting circuit 54. In normal operation, when spraying the product should not be detected by the presence sensor 56. The product detection can be interpreted as an anomaly. Means, such as an electronic device can signal this anomaly and / or stop the device. According to one embodiment, said heating and regulating means 4 comprise a heating body 40 having an inlet 41 for the liquid 20 and an outlet 42 for the heated liquid, as well as a temperature probe 43 targeting the temperature of the liquid at the outlet of said heating body 40. According to one embodiment, the heating body 40 has an electric heating resistor 44. According to one embodiment, the pumping means 3 consist of a peristaltic pump 30. According to a method of embodiment, the means 5 for spraying the heated liquid comprise a compressor device 55 for the production of said compressed air. We now describe in detail the embodiment illustrated in the figures.

As illustrated in FIG. 4, the compressed air arrives from the compressor device 55 into the compressed air supply 51 (hose). The compressed air passes into the nozzle via the channel 57 to enter a chamber 58 at the top of the nozzle 50. The air escapes at the orifice 59 at a narrowing. The shrinkage creates a venturi effect at the open end of a conduit 60. This depression is reflected in the conduit 60 of the nozzle 50, then in the channel 61, upstream, of greater diameter, to the product inlet. 62 of the nozzle 50. The air intake required for venturi suction passes through the venting circuit 54.

The heated liquid pushed by the peristaltic pump 30 arrives in the product supply pipe 63 and then flows into a sniffer 64. The product flows to the product inlet 62 of the nozzle 50 and is sucked by the depression due to the venturi effect.

The product arrives in the channel 61 and leaves the nozzle 50 through the conduit 60. The product then encounters compressed air at the open end of the conduit 60. The mixture Air / Product creates a mist called spray.

Without the assistance of the peristaltic pump 30, the quantity of product could not be guaranteed because of the flow fluctuations of the venturi.

Without venting the sniffer 64 the nozzle 50 would work by gavage, which would generate a poorer quality spray. The venturi effect makes it possible to obtain an optimized spray and the pump makes it possible to ensure the quantity of sprayed product.

The flow rate created by the venturi effect is approximately 25 ml / min and the pump delivers approximately 17 ml / min. The difference between the two flow rates makes it possible to draw air by venturi thanks to the setting circuit. atmosphere 54, which is constituted by a pipe whose one end opens in the open air and the other end opens into the sniffer 64. This difference in flow allows to create a sequential spray.

For this principle to work, it is imperative that the flow created by the venturi effect be greater than the flow rate of the pump 30.

Otherwise, the suction of the heated liquid at the fluid inlet 62 of the nozzle 50 is no longer sufficient to consume the product delivered by the peristaltic pump 30. The sniffer 64 would fill and the liquid would eventually flow through the venting circuit 54.

A presence sensor 56 is installed on the venting circuit 54 in order to verify whether the spraying is correct, and more particularly if the flow rate of the venturi is much greater than the flow rate of the pump.

For example, in the case of an obstruction of the duct 60 of the nozzle 50 the flow of the venturi decreases and becomes less than the flow rate of the peristaltic pump 30. For example take a venturi flow rate decreased to 15 ml / min. The difference between the two flow rates would be 2ml / min. The sniffer would eventually fill up at a rate of 2ml / min and the excess product would flow through the pipe venting circuit.

The sensor 56 would detect the abnormal presence of liquid in the circuit 54 and trigger a "plugged nozzle" alarm. In this case, electronics allow the control of a sequence during which the pump 30 is stopped and the compressor device 50 continues to deliver compressed air for a given time delay, for example about 40 seconds. The flow rate of the venturi then becomes greater than that of the pump (which is zero). The liquid is sucked in order to empty the sniffer 64. There is no spreading of product on the ground. Then the device stops and signals the fault to the user. The invention will now be illustrated by the following nonlimiting examples. EXAMPLES EXAMPLE 1: A 34 m3 room equipped with an automatic air extraction system was disinfected without human presence in the following manner using a device described above. Two disinfectant solutions (solution A and solution B) were evaluated: Solution A: Aseptanios AD marketed by Laboratoires Anios (Lille-Hellemmes, France), comprising 1250 ppm of peracetic acid, 2.5% of hydrogen peroxide, 4.4% acetic acid (ppm /% by weight relative to the total weight of the solution). Solution B: Aseptanios Oxy + marketed by Laboratoires Laboratoires Anios (Lille-Hellemmes, France), comprising 2500 ppm peracetic acid, 7% hydrogen peroxide, 3% acetic acid (ppm /% by weight relative to total weight of the solution). With the spraying device according to the invention, the disinfectant solution was heated to a temperature of 55 ° C and then sprayed to form a micro-mist having a disinfecting solution concentration of 7 ± 0.2 mL / m 3, term of the spray. The spraying step was followed by an air change step to remove the disinfectant solution from the room. When the concentration of hydrogen peroxide in the air is less than 1 ppm, the renewal of the air can be stopped. The efficiency of the process of the invention was evaluated according to the criteria of the French standard NF T72-281 version 2009. The results are summarized in Table 1 below. Solution A strain Solution B Sp4 bacteria 5 log reduction in 5 log reduction in 30 min 15 min Acinetobacter 5 log reduction in 5 log reduction in baumannii 15 min 15 min Aspergillus niger 4 log reduction in 4 log reduction in 120 min 60 min Candida albicans 4 log reduction in 4 log reduction in 15 min 15 min Bacillus subtilis 4 log reduction in 5 log reduction in 120 min 60 min Clostridium 4 log reduction in 5 log reduction in sporogenes 15 min 15 min Clostridium difficult 5 log reduction in 5 log reduction in 60 min. 15 min M avium 4 log reduction in 4 log reduction in 120 min: 60 min EXAMPLE 2 The tests of Example 1 were repeated with the difference that the disinfectant solution (solution A) had a temperature of 20 ° C. before spraying. The results (see Table 2 below) clearly show that the time required to reach a level of disinfection meeting the NF T72-281 standard increases significantly when the disinfectant solution is not heated before spraying. Table 2 Solution A strain at 20 ° C Solution A at 55 ° C Sp4 bacteria 5 log reduction in 5 log reduction in 60 minutes 30 minutes Acinetobacter 5 log reduction in 5 log reduction in baumannii 30 minutes 15 minutes Aspergillus niger Reduction 4 log reduction 4 log reduction in 180 minutes 120 minutes Candida albicans 4 log reduction in 4 log reduction in 30 minutes 15 minutes Bacillus subtilis 5 log reduction in 5 log reduction in 240 minutes 120 minutes Clostridium 5 log reduction in 5 log reduction in sporogenes 60 minutes 30 minutes EXAMPLE 3 The tests of Example 1 were repeated with the difference that the concentration of disinfecting solution (solution A) in the air was 5 ml / m3, at the end of spraying. The results (see Table 3 below) show that the time required to reach a disinfection level satisfying the NF T72-281 standard increases significantly when the disinfectant solution concentration is 5 ml / m3 instead of 7 ml / m3. .

Table 3 Strain Solution A 5 ml / m3 Solution A 7 ml / m3 Sp4 bacteria <5 log reduction in 5 log reduction in 120 minutes 30 minutes Acinetobacter <5 log reduction in 5 log reduction in baumannii 60 minutes 30 minutes Aspergillus niger Reduction <4 log in 4 log reduction in 180 minutes 120 minutes Candida albicans 3 log reduction in 4 log reduction in 120 minutes 30 minutes Bacillus subtilis <5 log reduction in 5 log reduction in> 240 minutes 120 minutes EXAMPLE 4 Solutions A and B were tested according to the protocol of Example 1 with different levels of air extraction: 42 renewals per hour (powerful extraction), 9 renewals (low extraction). The time required to obtain a disinfecting level satisfying the NF T72-281 standard was measured and then reach a concentration of hydrogen peroxide of less than or equal to 1 ppm, or even less than 0.1 ppm. Powerful Extraction 11 The time required to obtain a satisfactory bactericidal and yeasticidal effect is 30 min for solution A and the recovery time of the room (renewal of the air up to a level <0.1 ppm in H2O2) is 9 min. . The overall treatment time is 39 min. With solution B, the disinfection time is 15 min while the recovery time of the room is 24 min, the overall treatment time is therefore also 39 min. The time required to obtain a satisfactory fungicidal and sporicidal effect is 120 min for solution A and the recovery time of the room (renewal of air up to a level <0.1 ppm in H2O2) is 9 min. The overall processing time is therefore 129 min. With solution B, the disinfection time is 60 min while the recovery time of the room is 24 min, the overall treatment time is therefore also 84 min. If the detection threshold of H2O2 is increased to 1 ppm, the air renewal time drops to 6 min for solution A and 12 min for solution B. Low extraction The time required to obtain a bactericidal effect and satisfactory yeast is always 30 min for solution A and 15 min for solution B. The recovery time of the room (renewal of air up to a level <0.1 20 ppm H2O2) is 40 min for the solution A and 120 min for solution B. The overall treatment time is therefore 70 min for solution A and 125 min for solution B. The time required to obtain a satisfactory fungicidal and sporicidal effect is always 120 min. for the solution A and 60 min for the solution B. The recovery time of the room (renewal of the air up to a level <0.1 ppm in H2O2) is 40 min for the solution A and 120 min for solution B. The overall treatment time is therefore 160 min for the solution n A and 180 min for solution B.

If the H2O2 detection threshold is increased to 1 ppm, the air renewal time drops to 27 min for solution A and 60 for solution B. The present example shows that the process of the invention makes it possible to adapt the overall treatment times according to the desired disinfectant effect (bactericide, yeast, fungicide, sporicide), the level of air extraction of the room and the composition of the disinfectant solution. The method of the invention therefore allows great flexibility.

Claims (12)

REVENDICATIONS1. Air disinfection process comprising the following steps: providing a disinfectant solution, heating the disinfecting solution at a temperature of 40 to 65 ° C, spraying the heated disinfectant solution so as to obtain, at the end of the spraying, a disinfecting solution concentration in the predetermined air, the disinfecting solution comprising a peroxygenic acid and / or hydrogen peroxide. 2. Disinfection method according to claim 1, wherein the disinfecting solution is heated to a temperature of 50 to 60 ° C, preferably at about 55 ° C. 3. Disinfection method according to claim 1 or 2, wherein the concentration of disinfecting solution in the air is at the end of the spraying, 5 to 9 mL / m3. 4. Disinfection method according to claim 3, wherein the concentration of disinfectant solution in the air is at the end of the spraying, about 7 mL / m3. 5. Disinfection method according to any one of claims 1 to 4, wherein the disinfecting solution comprises peracetic acid and hydrogen peroxide. 6. Device (1) for spraying a liquid contained in a reservoir (2), comprising: - pumping means (3) for withdrawing the liquid in the reservoir (2), - means (4) for heating and regulating means for maintaining the temperature of the liquid taken from a predetermined temperature range; means (5) for spraying the heated liquid, comprising at least one spray nozzle (50). 7. Device according to claim 6, wherein said means (5) for spraying the heated liquid comprise, in addition to the spray nozzle (50), a supply (51) of compressed air for the propulsion of said heated liquid, mixed with said pressurized air. 8. Device according to claim 7, wherein said means (5) for spraying the heated liquid comprise a pressure regulating system (52), comprising: a venturi (53) controlled by said compressed air, the depression created by the air in the venturi for sucking a liquid at a given flow rate, greater than the flow rate of the pumping means (3), the difference between said determined flow rate and the flow rate of the pumping means producing an air suction, by venturi effect in admixture with said heated liquid, - a venting circuit (54) for said air suction, 9. Device according to claim 8, having a presence sensor (56), capable of detecting the presence of a liquid, arranged on said venting circuit (54), and means for stopping the spraying and / or triggering an alarm in the event that said presence sensor (56) detects a liquid in said venting circuit (54). 10. Device according to one of claims 6 to 9, wherein said means (4) for heating and control comprise a heating body (40) provided with an electric heating resistor (44), said heating body (40). ) having an inlet (41) for the liquid and an outlet (42) for the heated liquid, as well as a temperature probe (43) targeting the temperature of the liquid at the outlet of said heating body (40). 11. Device according to one of claims 6 to 10, wherein the pumping means (3) are constituted by a peristaltic pump (30). 12. Device according to one of claims 7, alone, or taken in combination with one of claims 8 to 11, wherein the means (5) for spraying the heated liquid comprises a compressor device (55) for the production of said pressurized air.