Device, method and modular system for producing aerosol mist of decontaminants

Abstract

The present invention concerns an atomizing device, a method and a modular system for the generation and discharge of an aerosol mist from a sterilizing solution. Particularly, the atomizing device, method and modular system are suitable for allowing a user to decide whether to produce a vapor or liquid base decontaminant from the sterilizing solution.

Description

DEVICE, METHOD AND MODULAR SYSTEM FOR PRODUCING AEROSOL MIST OF DECONTAMINANTSBackground of the InventionField of the Invention

[0001] The present invention concerns a device, a method and a modular system for the generation and discharge of an aerosol mist produced from a sterilizing solution, the mist containing either a vapor or solution droplets, or a mixture of these.Description of Related Art

[0002] When cleaning and disinfecting areas that require high purity, such as areas in hospitals or food and beverage industry or laboratories, the focus is usually on the visible surfaces. However, many pathogens are airborne, and may end up on hard-to-reach surfaces and in the air ducts. Manual decontamination and disinfection is laborious and the results may vary. Hard to reach spots may be left without cleaning. Therefore, wiping the visible surfaces with a disinfectant is not sufficient. Sterilizing or disinfecting vapors or sprays have thus been developed. Some of these decontaminants are used as liquids, others as vapors. For example, US 2004005240 Al describes the generation of a sterilizing mist, where the sterilizing solution is discharged in droplet form. CN 111658803, in turn, describes the use of an evaporated hydrogen peroxide spray. The sterilizing systems on the market, thus, fail to provide a versatility of the generated aerosol.

[0003] Further, in vapor generation, most techniques involve heating to evaporate liquid solutions of sterilizing agent. However, heating may cause decomposition of the sterilizing agent. This is known to take place, e.g., with hydrogen peroxide.

[0004] Consequently, there is still a need for new techniques for generating aerosol mists of sterilizing solutions, while providing an adjustability and thus versatility of the technique. Particularly, there is a need for a single system capable of delivering either liquid or vapor phase decontaminants, or vapor / liquid mixtures. Further, there is a lack of automated systems and battery-powered lightweight systems.Summary of the Invention

[0005] The invention is defined by the features of the independent claims. Some specific embodiments are defined in the dependent claims.

[0006] According to a first aspect of the present invention, there is provided a device and a method for the generation and discharge of an aerosol mist of a sterilizing solution.

[0007] According to a second aspect of the present invention, there is provided a device and method that provides versatility and adjustability for generation of aerosol mists.

[0008] According to a further aspect, there is provided a modular system including a plurality of such devices, each being adjustable.

[0009] To achieve the desired adjustability, the device can be assembled according to multiple assembly options, or two different main assembly options, resulting in different droplet size ranges in the resulting aerosol mist.

[0010] Thus, the invention relates to an atomizing device comprising an impaction space for forming an aerosol mist from a sterilizing solution, the impaction space including a feed system comprising one or more nozzle(s) for supplying sterilizing solution in a stream into the impaction space, and an outlet for leading a formed aerosol mist out of the impaction space.

[0011] Further, the impaction space comprises an impaction target arranged to cause collision of a fraction of the droplets of the aerosol when said impaction target is placed in the trajectory of the liquid stream led into the impaction space. Thus, as indicated above, in order to provide a user of the atomizing device with the option of deciding whether to produce a vapor or liquid base decontaminant, the atomizing device includes multiple assembly options, whereby in its first assembly option the impaction target is positioned in the trajectory of the stream led into the impaction space, and in its second assembly option the impaction target is positioned aside from the trajectory of the stream in the impactionspace. In a further alternative, several impaction targets can be used. In a preferred embodiment, each impaction target is a separate structure attached to the walls of the impaction space, instead of being solid walls of the impaction space, since this will facilitate the adjustability of the device, particularly when using movable impaction targets.

[0012] Likewise, the invention relates to a method comprising the steps of forming a stream of sterilizing solution, carrying said stream into an impaction space, and atomizing the sterilizing solution therein, thus forming an aerosol mist containing droplets.

[0013] The method is characterized by allowing a selection of the consistency of the aerosol mist by either leading the entire aerosol mist with the stream through a mist outlet out of the atomizing device, or by separating a fraction of droplets of sterilizing solution from the stream via collision against an impaction target, placed in the trajectory of the stream of sterilizing solution in an impaction space, thus separating the collided droplets from the stream and leading a modified aerosol mist out of the atomizing device, containing mainly small droplets, which are typically at least partially vaporized during the atomization.

[0014] Further, the invention relates to a modular system comprising a plurality of the herein described atomizing devices, wherein each of the atomizing devices can be controlled together or separately with a control unit or manually, thus providing the selection between the first assembly option and the second assembly option, or a further assembly option, separately for each atomizing device.

[0015] The atomizing device, the method and the modular system can be used, particularly, in disinfecting or decontaminating air and surfaces in a target volume.

[0016] Several advantages are achieved using the present invention. Among others, the invention provides an automatized decontamination system to deliver vapor and liquid mist decontaminants against biological and chemical threats. Particularly, the invention provides the possibility for a user to decide whether to produce a vapor or liquid base decontaminant from the sterilizing solution used for the aerosol mist.

[0017] The atomizing device of the invention does not require means for heating, whereby it can be implemented as a battery-powered lightweight system. Likewise, themethod of the invention can be operated without a heating step, thus resulting in a simpler method.

[0018] The atomizing device, method and modular system of the invention is suitable for use with various different decontaminants or sterilizing agents. If using one of the preferred alternatives of a hydrogen peroxide -based sterilizing solution, there is the advantage of using a sterilizing mist that leaves no harmful chemical residue.

[0019] When using the modular design, there is the additional advantage of ensuring an efficient spread of the decontaminant, or allowing the decontamination of multiple spaces at once.Brief Description of the Drawings

[0020] FIGURE 1 illustrates the structure of the atomizing device in accordance with at least some embodiments of the present invention, according to the described first assembly option, with A and B marking equally suitable structures with different positions of the nozzles and impaction targets in relation to the mist outlets, and the dotted arrows representing streams of gas, solution or mist.

[0021] Likewise, FIGURE 2 illustrates the structure of the atomizing device in accordance with at least some embodiments of the present invention, according to the described second assembly option, with A and B marking equally suitable structures with different positions of the nozzles in relation to the mist outlets, and the dotted arrows representing streams of gas, solution or mist.

[0022] FIGURES 3 a-e illustrate the structure of the atomizing device in accordance with other embodiments of the invention, showing possible preferred units of the feed system within the area marked with the dotted lines.

[0023] FIGURES 4a-4b show the structure of the nozzle type of Figs. 3d and e, where gas is used to drive the liquid through the nozzle, with an optional impaction target structure specified in FIG. 4b.

[0024] FIGURES 5a-c illustrate possible positions of the optional impaction target structure of Fig. 4b in relation to the nozzle(s), as a top view, with the position in Fig. 5a favouring vapour generation, the position of Fig. 5b favouring liquid mist generation, and the structure of Fig. 5c providing multiple nozzles, with separate nozzles combined with an impaction target and separate nozzles without impaction target.

[0025] FIGURE 6 shows the optional hinge structure of some embodiments, in the two different positions of the two herein described main assembly options, as a top view.

[0026] FIGURE 7 shows one possible position of the optional electrode of some embodiments, shown in a cross-section of the atomizing device, whereby the electrode is provided as a ring around a mist outlet.

[0027] FIGURE 8 illustrates the structure of a modular system of the invention, also showing the optional control unit.

[0028] FIGURES 9a and 9b illustrate the function of exemplary modular systems, showing optional further units intended for controlling the modular system, or for controlling each separate atomizing device, the modular system operated either using a single sterilizing solution (Fig. 9a) or a plurality of solutions from different reservoirs (Fig.9b).

[0029] FIGURE 10 is an example of a more detailed scheme of the function of the optional control unit.

[0030] FIGURE 11 is an example of a more detailed scheme of the function and control of the optional dehumidifier.Embodiments of the Invention

[0031] DefinitionsIn the present context, the term “aerosol” is intended to encompass a suspension of fine liquid droplets. It tends to form a mist that can be sprayed e.g. into an area to be decontaminated. Further, when separating the fineliquid droplets from the larger ones, the small (or fine) droplet fraction allows for evaporation of at least a fraction of the droplets in the fraction.The term “fine liquid droplets” of the mist or of a fraction of the mist is, in turn, intended to define droplets that have a sufficiently small inertia that allows them to be carried in the trajectory of a jet or stream of the mist, even when the stream changes its direction. Typically, such small droplets of the mist have an diameter of <10pm, preferably <5 pm, giving them a sharp surface curvature that also facilitates evaporation. Larger droplet fractions, in turn, tend to remain in liquid form. These droplet diameters may be measured e.g. by using optical methods, such as an optical particle sizer.

[0032] The present invention thus relates to an atomizing device (see Figs. 1 and 2) for the generation and discharge of an aerosol mist from a sterilizing solution, the atomizing device comprising an impaction space 1 for forming an aerosol mist from a sterilizing solution, the impaction space 1 comprising- a feed system 2 comprising one or more nozzle(s) 2’ for supplying sterilizing solution in a stream into the impaction space 1, and- a mist outlet 3 for leading a formed aerosol mist out of the impaction space 1, wherein the impaction space 1 comprises an impaction target 4 arranged to cause collision of a fraction of the droplets of the aerosol against said impaction target 4 when it is placed in the trajectory of the stream led into the impaction space 1, and wherein the atomizing device is adjustable, whereby in its first assembly option the impaction target 4 is positioned in the trajectory of the stream led into the impaction space 1 (see Fig. 1), and in its second assembly option the impaction target 4 is positioned aside from the trajectory of the stream in the impaction space 1 (see Fig. 2).

[0033] Of the nozzles 2’, one or more are typically impactor nozzles arranged to receive the sterilizing solution that is pumped to the impaction space 1, and carry it as a stream of droplets into the impaction space 1 (see Figs. 3a-c). In case the impactor nozzle can take part in the atomization, it can also be called an atomizing nozzle (see Fig. 3a). Preferably, an atomizing nozzle (as in Fig. 3a) has an outlet with a width of 0.01-lmm, more preferably 0.05-0.75mm, and most suitably 0.1-0.5mm, as the outlet of the nozzle affects the size of the droplets in the aerosol mist, a wide outlet resulting in a coarse mistand a narrow outlet resulting in a fine mist. A pneumatic nozzle in turn (see Figs. 3b-e), utilizing a carrier gas in the atomization, may have a preferred outlet width of 0.01-10mm, more preferably 0.1-3.0mm, and most suitably 0.3-1.5mm.

[0034] As indicated above, the atomizing device, or its impaction space 1, comprises a feed system 2, which is intended for supplying sterilizing solution from a reservoir 5 to the impaction space 1. In embodiments shown in Figs 3a-e, the impaction space 1 and the feed system 2 connected thereto typically further comprises one or more of the following: i) In this first alternative, one or more ejectors 7 (see Figs. 3b, d) are arranged to transfer sterilizing solution from a reservoir 5 holding the solution via a liquid channel 6 via a nozzle 2’ to the impaction space 1 by means of Venturi effect, for example with the help of a gas distributor 8, arranged in fluid communication with the reservoir 5 holding the solution and the liquid channel 6, for creating a jet of pressurized carrier gas, for carrying the sterilizing solution from the reservoir 5 via the liquid channel 6 and the feed system 2 into the impaction space 1.ii) In this second alternative, one or more liquid pumps 9, arranged to pump the sterilizing solution from a reservoir 5 holding the solution via a liquid channel 6 to the impaction space 1 (see Fig. 3a, c, e), although in an embodiment, the atomization may still be facilitated with the help of a gas, whereby the feed system 2 may include also a gas distributor 8 and a gas nozzle 2” (see Fig. 3c). Thus, the ejector 7 can be replaced by a liquid pump 9, as in these Figs. 3a, c, e.Alternatively, the ejector 7 principle can be utilized also, with the liquid pump 9. iii) In this third alternative, a liquid channel 6 is arranged to feed the sterilizing solution from a reservoir 5 holding the solution, placed at an elevated position, to the impaction space 1 by gravitational forces (not shown in the Figures).iv) In this fourth alternative, a liquid channel 6 is arranged to feed the sterilizing solution from a pressurized reservoir 5 holding the solution, to the impaction space 1 by a pressure difference (not shown in the Figures).

[0035] Any of these feed system 2 alternatives i)-iv) can be used alone, or in a combination of units from separate alternatives.

[0036] Thus, in the structure of Fig. 3a, liquid is drawn up from a reservoir 5 by utilizing a pump 9, which is efficient enough to cause atomization in the impactor nozzle 2’ without requiring a carrier gas.

[0037] In the structure of Fig. 3b, liquid is drawn up from a reservoir 5 via the Venturi effect, by utilizing an ejector 7 and a gas carried from a gas distributor through a gas nozzle 2”. Thus, the atomization takes place at the gas nozzle 2”, before being carried through the impactor nozzle 2’ into the impaction space 1.

[0038] In the structure of Fig. 3c, liquid is drawn up from a reservoir 5 by utilizing a pump 9, whereas the atomization takes place at least partly already in the space before the impactor nozzle 2’, with the help of pressurized gas, which is obtained from the gas distributor 8 through the gas nozzle 2” and is mixed with the sterilizing solution in the space before the impactor nozzle 2’.

[0039] The structure of Fig. 3d includes two superposed nozzles 2’ forming an pneumatic atomizer nozzle structure, i.e. a liquid nozzle 2’, for carrying the sterilizing solution into the impaction space 1, and a gas nozzle 2”, the gas nozzle 2” forming the center of the complete nozzle structure. Thus, this nozzle structure functions by the ejector principle, utilizing the Venturi effect, whereby the nozzle structure also forms an ejector 7. The atomization in this alternative takes place at the outlet of the nozzle structure.

[0040] The structure of Fig. 3e is highly similar to the structure of Fig. 3d, although the sterilizing solution is fed to the nozzle structure described above using a liquid pump 9, thus providing an alternative, but yet efficient atomization.

[0041] A particularly preferred feed system 2 comprises a pneumatic nozzle structure as shown in Figs. 3d-e, wherein the atomization is facilitated with the help of a gas fed into the same nozzle structure as the stream of sterilizing solution. Of these alternatives, the embodiment of Fig. 3d is most preferred, as it can function without a pump.

[0042] The pneumatic nozzle structure is further specified in Fig. 4a. In this nozzle structure, the liquid nozzle 2’ outlet preferably has a diameter that is larger than the separate gas nozzle 2” outlet of the structure (see Fig. 4a). A preferred position of the impaction target (or baffle) 4 in relation to said nozzle structure outlet is shown in Fig. 4b.According to an example, the diameter of the gas nozzle 2” can be 0.5mm and the diameter of the liquid nozzle 2’ can be 0.65mm. Likewise, a particularly preferred distance from the nozzle 2’ outlet to the impaction target 4 is 1-2 times the diameter of the liquid nozzle 2’ (see Fig. 4b), whereby an example of the distance is 0.65mm, and another example is 1.3mm. Further, as shown in the experiments carried out in the below example, the diameter d of the gas nozzle 2” can be 0.5mm, the diameter D of the liquid nozzle 2’ can be 0.9mm, and the distance A from the nozzle 2’ to the impaction target can be 0.9mm.

[0043] The atomizing device, or its impaction space 1, is configured to be adjustable. In other words, the atomizing device is intended to provide droplet diameters in the aerosol mist that belong to different size ranges depending on which one of the different specifically described assembly options of the atomizing device is applied.

[0044] When the stream of sterilizing solution is conducted towards the impaction target 4, by using the first assembly option (see Fig. 1), wherein the impaction target 4 is positioned in the trajectory of the stream in the impaction space 1, the product mist will be formed of droplets with a smaller diameter, while a majority of droplets with a diameter of >10pm, preferably >5 pm, are removed from the mist. This mist of smaller droplets is caused by the collision of at least the larger droplets against the impaction target 4, which will cause these larger droplets to be separated from the mist, since their inertia is too high to change their direction when facing a surface. The mist being conducted past the impaction target 4 to the mist outlet 3 thus contains mainly smaller droplets.

[0045] When the stream of sterilizing solution is conducted past the impaction target 4, by using the second assembly option (see Fig. 2), wherein the impaction target 4 is positioned aside from the trajectory of the stream in the impaction space 1, the product mist will be formed of droplets including those with larger diameters, such as diameters of >10pm.

[0046] Also a third assembly option exists, according to which, the impaction target 4 is positioned to be partly in the trajectory of the stream in the impaction space 1.According to this option, the product mist will be partly modified, with a main fraction of the droplets having small diameters of <5 pm, but also including droplets of >10 pm. A more preferred manner of achieving such a partly modified product mist is, however, touse an atomizing device with multiple impactor nozzles 2’, only a part of which are coupled with impaction targets 4 (see Fig. 5c).

[0047] In an embodiment aimed at optimizing the ratio of droplets hitting / passing the impaction target 4, the impaction target 4 is placed at a distance from the mist outlet 3 of the impaction space 1 that is 0.1-10 times the width of the mist outlet 3, preferably 0.5-5.0 times the width of the mist outlet 3, and more preferably 1-2.5 times the width of the mist outlet 3.

[0048] Another alternative for optimizing the ratio of droplets hitting / passing the impaction target 4, is to limit the width of the impaction target to be as small as possible, while still being able to facilitate efficient impaction with the large droplets. Generally, the width of the target should be less than 20 times the diameter of the nozzle orifice. Further, the impaction target can be rounded to maximize the space around the impaction space, which prevents coagulation of small droplets into the larger ones.

[0049] To facilitate the separation of droplets, the impaction target 4 and the mist outlet 3 may further be positioned at levels preventing the direct discharge of droplets ricocheting from the impaction target 4.

[0050] Further, in an embodiment of the invention, the nozzle 2’ and the mist outlet 3 may be positioned at an angle to each other (see Fig. 1 A and Fig. 2A), to cause the stream of the mist to change its direction within the impaction space 1, thus causing large droplets to hit a surface of the container, while small droplets are forced to change their direction, and are carried with the stream to the mist outlet 3. Thus, some options of this embodiment include:- positioning the nozzle 2’ to create a trajectory for the stream through the nozzle 2’ having a first orientation,- positioning the mist outlet 3 to create a trajectory for the stream through the mist outlet 3 having a second orientation, and- limiting the angle between the first orientation in respect to the second orientation to an angle between 60 and 120 °,thus leading the largest droplets towards the walls of the container optionally to be returned to a reservoir 5 instead of being discharged through the mist outlet 3.

[0051] Also other options exist, however, and are within the knowledge of a person of average skill in the art. Options A and B of Figs. 1 and 2 are only two of multiple options.

[0052] The adjustability of the atomizing device, or its impaction space 1, is essential, but it can be achieved using different structures, i.e. the different assembly options mentioned in this disclosure.

[0053] In a first embodiment (see Figs. 5a-b and Fig. 6), the adjustability of the atomizing device, or its impaction space 1, is implemented by providing a movable impaction target 4, for example connected to a hinge 10 that is capable of moving the impaction target 4 out of the trajectory of the stream led into the impaction space l.In Figs.5a and 5b, the hinge 10 is shown as a rotating arm that holds the impaction target(s) 4, with the position of the first assembly option shown in Fig. 5a and the position of the second assembly option shown in Fig. 5b. In Fig. 6 it is shown as a back and forth turning arm. However, also other equally functional options exist.

[0054] In a second embodiment, shown in Fig. 5c, the adjustability is provided without a hinge structure 10, instead providing a plurality of nozzles 2’, particularly two or more nozzles 2’, one or more with impaction targets 4 placed in the trajectory of the stream in the impaction space 1 and one or more without impaction targets 4. In this option, the selection between vapor and mist production is made by directing the stream led to the impaction space 1 to the corresponding set of nozzles 2’. Thus, at least a first nozzle 2’ is arranged to guide the stream in the impaction space 1 into a trajectory that results in a collision with an impaction target 4, and at least a second nozzle 2’ is arranged to guide the stream in the impaction space 1 into a trajectory that passes any impaction targets 4.

[0055] In a third embodiment (not shown in the Figs), the adjustability of the atomizing device, or its impaction space 1, is implemented by providing one or more movable nozzles 2’, for example with the nozzles 2’ (instead of the impaction targets 4) connected to hinges 10 that are capable of moving the nozzle(s) 2’ into a first position guiding the stream in the impaction space 1 into a trajectory that results in a collision with an impaction target 4, and capable of moving the nozzle(s) 2’ into a second positionguiding the stream in the impaction space 1 into a trajectory that passes any impaction targets 4.

[0056] The atomizing device can be operated either by pressurizing the sterilizing solution, thus providing a jet stream of sterilizing solution led into a nozzle 2’ of the impaction space 1, or by carrying the solution through a nozzle 2’ with the help of a pressurized gas. Thus, the jet stream can be achieved e.g. using a liquid pump 9, the help of a carrier gas or gravitational forces. The optional carrier gas stream can, in turn, be produced and carried to the atomizing device from a gas distributor 8, possibly operated with the help of, or being, a separate gas pump 8’ (or compressor), but preferably being in the form of a gas pressurizer, a fan or a blower. The optional gas distributor 8 is thus preferably connected to the atomizing device, or its impaction space 1, via the same impactor nozzle(s) 2’ as the liquid channel 6, or via its own gas nozzle 2”.

[0057] In an alternative embodiment, also a separate inlet for flushing gas can be included in the impaction space 1. This separate flushing gas will create a gas flow into the container, separate from the liquid stream, thus not taking part in the atomization, but facilitating the discharge of the generated mist and enhancing the diffusion and optional evaporation of droplets in the stream discharged through the mist outlet 3.

[0058] In a further preferred embodiment, the impaction space 1 comprises an electrode 11, particularly being a high-voltage electrode 11, for providing a unipolar charge in the aerosol mist, for guiding the aerosol mist onto surfaces to be disinfected or decontaminated, and optionally for facilitating evaporation when evaporation is aimed for. In particular, in coarse or liquid mist mode, when the atomizing device, or its impaction space 1, is arranged according to its second assembly option, the high-voltage electrode 11 applies the voltage to assist the deposition of the liquid mist onto surfaces. In fine or vapour mist mode, the charging may further assist evaporation, e.g. by repulsive forces leading to an explosion of the droplets. Further, charging of the mist may lead to the formation of more reactive species of decontaminants, thus enhancing decontamination. The electrode 11 is preferably positioned as a ring electrode around the mist outlet 3 (see Fig. 7), whereby it is positioned in the close vicinity to the aerosol mist led out of the impaction space 1. Alternatively, it can be positioned around the impactor nozzle 2’.

[0059] In an embodiment, the atomizing device may further include a control unit 12 (see Fig. 8), typically connected to a input / output (I / O) controller 12’ and / or a power source 12”, for controlling the selection between the first assembly option and the second assembly option and for controlling various units of the atomizing device, whereby these units of the device (see Fig. 9) may include also a sensor 13 (or probe) capable of measuring the temperature (T) and relative humidity (RH) in the space to be decontaminated, or separate sensors 13-T and 13-RH for the temperature and for the relative humidity, and optional sensors 13-S for measuring the content(s) of sterilizing solution, such as hydrogen peroxide and / or ammonia in the space to be decontaminated. Also one or more sensor(s) 13-C for measuring the decontaminant concentration in the space to be decontaminated can be included in the atomizing device, as well as a dehumidifier 14 for controlling the humidity in the space to be decontaminated before use of the atomizing device. However, this control may also be done manually.

[0060] Since many sterilizing solutions consist of highly reactive agents, such as strong oxidants, the atomizing device is typically made of durable material, not interfering with the sterilizing solution. Preferred materials are plastic, glass, or metal, more preferably being plastic or glass or various combinations of these. For example, when using a sterilizing solution containing hydrogen peroxide, it is preferred to avoid metals, since metals can cause an undesirable reaction with e.g. hydrogen peroxide. In a typical option, at least a majority of the units of the atomizing device are made of plastic, among others since plastic is a versatile, inert, durable and lightweight material.

[0061] An example embodiment may include e.g. the structure of Figs. 1A, 2Aand 3d, with either the structure of Fig 5a and 5b, or the structure of Fig. 6.

[0062] The atomizing device as disclosed above can be applied for instance in the method of the invention, also intended for the generation and discharge of an aerosol mist from a sterilizing solution. Thus, the method can utilize either the atomizing device disclosed herein, or it can utilize a different apparatus, while it preferably utilizes the herein disclosed atomizing device.

[0063] Said method for the generation and discharge of an aerosol mist from a sterilizing solution comprises the steps offorming a stream of sterilizing solution,carrying the stream into an impaction space 1, andatomizing the sterilizing solution in the impaction space 1, thus forming an aerosol mist containing liquid droplets,which method is characterized by selecting the consistency of the aerosol mist by either leading the entire aerosol mist with the stream through a mist outlet 3 out of the impaction space 1, or separating a fraction of droplets of sterilizing solution from the stream via collision against an impaction target 4, placed in the trajectory of the stream of sterilizing solution in the impaction space 1, thus separating the collided droplets from the stream carried to the mist outlet 3 and leading a modified aerosol mist out of the impaction space 1.

[0064] The aerosol mist is typically formed by atomizing the liquid solution into droplets, preferably by driving the liquid solution through one or more nozzles 2’, more preferably at high pressure, optionally using a carrier gas that may also be fed to the impaction space 1 through a separate gas nozzle 2 positioned by the impactor nozzle 2’. Most suitably, the aerosol mist is formed with the help of a pressurized gas, typically being pressurized air.

[0065] The method may be operated at ambient temperature, whereby no heating is required. Likewise, the atomizing device does not require any means for heating.

[0066] As stated above, the sterilizing solution is carried as a stream, typically at high pressure, via one or more nozzles 2 into the impaction space 1. Feeding the solution to the nozzle can be carried out by- using one or more vacuum ejectors 7, which transfer sterilizing solution by means of underpressure created by Venturi effect, e.g. with the help of a jet of pressurized carrier gas,- pumping the sterilizing solution using one or more liquid pumps 8,- using gravitational forces to feed the sterilizing solution, or- driving the sterilizing solution to the atomizer by pressurizing the reservoir containing the solution.

[0067] The method of the invention is characterized by being adjustable. In other words, the method is intended to provide an aerosol mist having a selected range for the droplet diameter in the aerosol mist that depends on whether the droplets are collided against an impaction target 4 or led past it.

[0068] In one embodiment of the invention, the droplets of the stream of sterilizing solution are led to the mist outlet 3 without being collided. Thus, the formed aerosol mist will have a wider range for the droplet diameters, making them liquid droplets.

[0069] In another embodiment (collision embodiment), the droplets in the aerosol mist are at least partly evaporated, preferably by limiting the diameter of the droplets in the formed aerosol mist to provide a mist in which at least 50% of the droplets with a diameter of >10pm, preferably >5pm, are removed. The removal of large droplets takes place by colliding the droplets, or the largest droplets, particularly, against an impaction target 4.

[0070] Typically, in this latter embodiment (collision embodiment), the largest droplets will collide against the impaction target 4, and will either be separated from the stream or atomized into smaller droplets, whereby the aerosol mist that is carried to the mist outlet 3 includes mainly smaller droplets, which are easily evaporated even at ambient temperature. Thus, vapour can be generated even without added heat, due to the separation of the largest droplets of the sterilizing solution, whereby the method of the present disclosure can be operated at ambient temperature.

[0071] The liquid from the largest droplets separated from the gas stream is preferably returned to a reservoir 5 for holding sterilizing solution, and can be used to feed more sterilizing solution to the method.

[0072] Due to the small size of the droplets remaining in the mist in this latter embodiment (collision embodiment), evaporation is spontaneous, thus resulting in a vapour-containing mist. The evaporation is aided by the sharp surface curvature of the small droplets.

[0073] The separation of a fraction of droplets can be further facilitated by positioning the mist outlet 3 at a position that forces the stream to change its directionwithin the impaction space 1, whereby the inertia of the larger droplets will cause their separation from the stream led to the mist outlet 3.

[0074] In an embodiment, a gas can be used to drive the sterilizing solution through the impaction space 1. This carrier gas can be any suitable gas. Particularly, the gas can be selected from nitrogen, carbon dioxide, oxygen, argon or air, or another suitable gas, preferably being air. Another alternative is to use a separate flushing gas to facilitate carrying the formed mist out of the container, which flushing gas can also be selected from the above mentioned list of gases.

[0075] In embodiments requiring a high-velocity gas stream, particularly where the gas stream is intended to take part in the atomization of the droplets of sterilizing solution, the gas is preferably supplied at high pressure, such as a pressure of > 0.5bar, more preferably at a pressure of 2-10bar.

[0076] The sterilizing solution used in the herein disclosed method can be selected from any solution containing one or more sterilizing agents, which are volatile enough to be evaporated from small droplets at ambient temperature. It can be used as a 100% solution of the selected sterilizing agent(s), or it can be diluted with water or other solvent, depending on the selected agents. A preferred sterilizing agent is an aqueous solution of hydrogen peroxide, which may be mixed with one or more additives, such as ammonia or acetic acid. Another preferred solution is an aqueous solution of ammonia, used alone, or mixed with one or more additives, such as hydrogen peroxide. Further alternative sterilizing agents can be selected from ozone, ethylene oxide, formaldehyde, chlorine, chlorine dioxide or nitrogen dioxide, which can either be used alone, as such, or as aqueous solutions, depending on the character of the sterilizing agent, or as additives mixed with the above hydrogen peroxide or ammonia, to further enhance the sterilization process, and provide a synergistic effect.

[0077] In a preferred embodiment, the sterilizing solution is a solution containing hydrogen peroxide in water, preferably in a hydrogen peroxide concentration of l-65mass-%, more preferably in a concentration of 16-65mass-%, even more preferably in a concentration of 30-65mass-%, most suitably in a concentration of 35-50mass-%, the method thus forming a hydrogen peroxide aerosol.

[0078] One alternative is to add acetic acid to the preferred hydrogen peroxide solution, particularly in a concentration of < 10mass%, preferably < 7mass%, and most suitably in a concentration of about 5mass%.

[0079] In another preferred embodiment, the sterilizing solution is a solution containing ammonia, preferably as an aqueous solution, more preferably in a concentration of 10-35 mass-%, most suitably in a concentration of 25-35 mass-%.

[0080] Also this embodiment encompasses the alternative of adding acetic acid to the solution, but this alternative results in a mixture of ammonia and acetic acid, which will be partially neutralized.

[0081] In another embodiment, the method herein described is carried out with the help of an electrical charge created in the stream of sterilizing solution. This embodiment has the further advantage of facilitating the mist formation, and depending on the other selections made within the scope of the method, possibly also facilitating evaporation. Additionally, the electrical charge in the mist will guide the aerosol mist onto surfaces to be disinfected or decontaminated.

[0082] The invention described herein also encompasses a modular system for the generation and discharge of an aerosol mist from a sterilizing solution, which modular system comprises a plurality of atomizing devices as described in the present disclosure, wherein each of the atomizing devices can be controlled together or separately with a control unit 12, thus providing the selection between the first assembly option and the second assembly option separately for each atomizing device. The control unit 12 can either be connected to the atomizing device via a wire, or it can be connected wirelessly. Both separate atomizing devices and this modular system can, however, be operated also manually, without the control unit 12.

[0083] In one alternative, a modular system can include a plurality of control units 12, e.g., divided so that each atomizing device of the modular system can have its own control unit 12. However, it is preferred to control the entire modular system using one control unit 12 (see Fig. 8).

[0084] In case of this modular system, the above-described further sensors / probes 13 and dehumidifiers 14 (see Fig. 9) can be provided separately for each atomizing device, but in a preferred alternative, one of each sensor 13 and dehumidifier 14 is included for each modular system, and controlled using a single control unit 12, possibly further connected to a signal module (I / O controller) 12’ and / or a power source 12”, for controlling the various units of the atomizing device (see also Fig. 10).

[0085] A control unit 12 may include also a detachable control panel and control electronics, which are connected to each atomizing device of the system.

[0086] The above-described atomizing device, method and modular system are suitable for use, e.g., in disinfecting or decontaminating air and surfaces in a target volume, preferably in a closed space, such as in a room or an air duct. In such a use, a small concentration of the mist of the invention is sufficient, e.g., a concentration of 100-1000 ppm, and allowing the mist to react for > 5min, preferably > Ih.

[0087] In case of the modular system, the atomizing devices are preferably placed in different sections or compartments of the space to be decontaminated to ensure efficient and even distribution of the decontaminant. While most of the units of the atomizing device, or preferably the entire atomizing device, typically are placed within the space(s) to be decontaminated, the control unit 12 is preferably placed outside of said space(s).Further, the separate atomizing devices of the modular system may be operated using different sterilizing solutions (see Fig. 9b), either to obtain different sterilizing effects in different spaces to be decontaminated, or to cause mixing of the sterilizing agents at the site(s) of decontamination, with the decontaminants in the produced aerosol mists form. In such a case, there is preferably only one reservoir 5 holding each sterilizing solution, while the same solution can be fed via multiple liquid channels 6 to multiple atomizing devices. In case of using only one sterilizing solution, it is naturally sufficient to use a single reservoir 5 (see Fig. 9a). However, using separate reservoirs 5 for each atomizing device within the modular system is also within the scope of the invention.

[0088] In one embodiment, the space(s) to be decontaminated is / are dried or dehumidified before decontamination, particularly if the decontaminant is hydrogen peroxide, since high humidity may prevent reaching a sufficiently high concentration of vaporous hydrogen peroxide in the space to be decontaminated, as the humidity can causethe water / hydrogen peroxide vapor mixture to reach saturation. For this purpose, it is possible to use, e.g., a dehumidifier 14, connected to the atomizing device or the modular system either with a wire or wirelessly. The control unit 12 can be used also to control said dehumidifier 14 (see Fig. 11), and thus control the humidity in the space to be decontaminated.

[0089] Further, it is advantageous to seal the space(s) to be decontaminated before running the atomizing device, method or modular system described herein, to prevent the escape of decontaminants. After running a predetermined decontamination cycle, and aerating the decontaminated space(s), e.g. by opening doors or windows, to remove possible decontaminant residues, the use of the space(s) can be started again, as they have been decontaminated.

[0090] It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0091] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Where reference is made to a numerical value using a term such as, for example, about or substantially, the exact numerical value is also disclosed.

[0092] As used herein, a plurality of items, structural elements, compositional elements, and / or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. In addition, various embodiments and examples of the present invention may be referred to herein along with alternatives for the various components thereof. It is understood that such embodiments, examples, and alternativesare not to be construed as de facto equivalents of one another, but are to be considered as separate and autonomous representations of the present invention.

[0093] Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In this description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one or more of the specific details.

[0094] While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.Example

[0095] An atomizing device similar to Fig 3e, utilizing the nozzle structure of Fig.4b (with diameter d being 0.5mm, diameter D being 0.9mm, and distance A being 0.9mm) was tested by producing an aerosol mist from non-volatile diethyl-heptyl-sebacate solution with and without positioning the impactor target in the trajectory of the stream led into the impaction space of the device (i.e. by separately testing the first assembly option shown in Fig. lAand the second assembly option shown in Fig. 2A). The mass concentration of the aerosol obtained from the device was measured with and optical particle counter.

[0096] Using the impactor target in the first assembly option of the device cut off at least 70% of the total aerosol mass concentration, compared to the aerosol obtained using the second assembly option of the device.

[0097] It is worth noting, that the largest droplets containing most mass are lost due to depositional losses and they were not detected by the optical particle counter. Thus, in reality, using the impactor target cut off more than 70% of the particle mass concentration.Industrial Applicability

[0098] The present device, method and modular system can be used for high efficiency aerosol or vapor generation, and generally for replacement of conventional apparatuses for generation and discharge of mists of various sterilizing solutions.

[0099] Particularly, the present device, method and modular system can be used to decontaminate spaces in civil or military applications. For example, spaces in buildings, such as hospitals, or vehicles, can be decontaminated after chemical or biological contamination, or containers holding foodstuffs.Reference Signs List1 impaction space2 feed system2’ nozzle2” separate gas nozzle3 mist outlet4 impaction target5 reservoir6 liquid channel7 vacuum ejector8 gas distributor8’ gas pump9 liquid pump10 hinge11 electrode12 control unit12’ signal module12” power source13 sensor13-T temperature sensor13-RH relative humidity sensor 13-S sterilizing solution sensor 13-C decontaminant sensor 14 dehumidifierCitation ListPatent LiteratureCN 111658803US 2004005240 Al

Claims

Claims1. An atomizing device for the generation and discharge of an aerosol mist from a sterilizing solution, the atomizing device comprising an impaction space (1) for forming an aerosol mist from a sterilizing solution, the impaction space (1) comprising- a feed system (2) comprising one or more nozzle(s) (2’) for supplying sterilizing solution in the form of a stream into the impaction space (1), and- a mist outlet (3) for leading a formed aerosol mist out of the impaction space (1), characterized in that- the impaction space (1) further comprises an impaction target (4) arranged to cause collision of a fraction of the droplets of the aerosol against said impaction target (4) when it is placed in the trajectory of the stream led into the impaction space (1), and in that- the atomizing device is adjustable, whereby in its first assembly option the impaction target (4) is positioned in the trajectory of the stream led into the impaction space (1), and in its second assembly option the impaction target (4) is positioned aside from the trajectory of the stream in the impaction space (1).

2. The atomizing device of claim 1, wherein the one or more nozzles (2’) are atomizing nozzles arranged either to mix the sterilizing solution with a created high velocity jet of the stream led into the impaction space (1), or arranged to receive the sterilizing solution that is pumped through the atomizing nozzle (2’) at high pressure.

3. The atomizing device of claim 1 or 2, wherein the feed system (2) comprises a nozzle (2’), e.g. an atomizing nozzle having an outlet width of 0.01-lmm, preferably 0.05-0.75mm, and most suitably 0.1 -0.5mm, or a pneumatic nozzle having an outlet with a width of O.Ol-lOmm, preferably 0.1-3.0mm, more preferably 0.3-1.5mm.

4. The atomizing device of any preceding claim, wherein the impaction target (4) is placed at a distance from the mist outlet (3) of the impaction space (1) that is 0.1-10 times the width of the mist outlet (3), preferably 0.5-5.0 times the width of the mist outlet (3), and more preferably 1-2.5 times the width of the mist outlet (3).

5. The atomizing device of any preceding claim, wherein the feed system (2) is in the form ofi. one or more ejectors (7), arranged to transfer sterilizing solution from a reservoir (5) holding the solution via a liquid channel (6) via a feed system (2) to an impaction space (1) by means of Venturi effect, for example with the help of a gas distributor (8), arranged in fluid communication with the reservoir (5) holding the solution and the liquid channel (6), for creating a jet of pressurized carrier gas, for carrying the sterilizing solution from the reservoir (5) via the channel (6) and the feed system (2) into the impaction space (1),ii. one or more liquid pumps (9), arranged to pump the sterilizing solution from a reservoir (5) holding the solution via a liquid channel (6) to the impaction space (1),iii. a liquid channel (6) arranged to feed the sterilizing solution from a reservoir (5) holding the solution, placed at an elevated position, to the impaction space (1) by gravitational forces, oriv. a liquid channel (6) arranged to feed the sterilizing solution from a pressurized reservoir (5) holding the solution to the impaction space (1) by a pressure difference.

6. The atomizing device of any of claims 1 to 5, wherein the adjustability of the impaction space (1) is implemented by providing a movable impaction target (4), for example connected to a hinge (10) that is capable of moving the impaction target (4) out of the trajectory of the stream led into the impaction space (1).

7. The atomizing device of any of claims 1 to 5, wherein the adjustability of the impaction space (1) is implemented by providing one or more nozzles (2’) as a movable nozzle (2’), for example connected to a hinge (10) that is capable of moving the nozzle (2’) into a first position guiding the stream in the impaction space (1) into a trajectory that results in a collision with an impaction target (4), and capable of moving the nozzle (2’) into a second position guiding the stream in the impaction space (1) into a trajectory that passes any impaction targets (4).

8. The atomizing device of any of claims 1 to 5, wherein the adjustability of the impaction space (1) is implemented by providing two or more nozzles (2’) for supplying sterilizing solution to the impaction space (1), at least a first nozzle (2’) arranged to guidethe stream in the impaction space (1) into a trajectory that results in a collision with an impaction target (4), and at least a second nozzle (2’) arranged to guide the stream in the impaction space (1) into a trajectory that passes any impaction targets (4).

9. The atomizing device of any preceding claim, comprising an electrode (11) for providing an electrical charge in the aerosol mist, for further facilitating the mist formation, and optionally facilitating evaporation, and for guiding the aerosol mist onto surfaces to be disinfected or decontaminated.

10. Method for the generation and discharge of an aerosol mist from a sterilizing solution, comprising the steps of- forming a stream of sterilizing solution,- carrying the stream into an impaction space (1), and- atomizing the sterilizing solution in the impaction space (1), thus forming an aerosol mist containing liquid droplets,characterized by selecting the consistency of the aerosol mist by either leading the entire aerosol mist with the stream through a mist outlet (3) out of the impaction space (1), or separating a fraction of droplets of sterilizing solution from the stream via collision against an impaction target (4), placed in the trajectory of the stream of sterilizing solution in the impaction space (1), thus separating the collided droplets from the stream carried to the mist outlet (3) and leading a modified aerosol mist out of the impaction space (1).

11. The method of claim 10, wherein the aerosol mist is formed by atomizing the sterilizing solution, by driving the solution as a high velocity jet through one or more atomizing nozzles (2’).

12. The method of claim 10 or 11, wherein the sterilizing solution is fed to the impaction space (1) in a separate feeding step by- using one or more vacuum ejectors (7), which transfer sterilizing solution by means of Venturi effect,- pumping the sterilizing solution using one or more liquid pumps (8),- using gravitational forces to feed the sterilizing solution, or- using a jet of pressurized carrier gas to form the stream.

13. The method of any of claims 10 to 12, wherein a fraction of droplets of sterilizing solution is separated from the stream by colliding the fraction of droplets against an impaction target (4), and returning these droplets to a reservoir (5).

14. The method of any of claims 10 to 13, wherein the aerosol mist is modified, preferably by limiting the presence of large droplets so that a majority of droplets with a diameter of >10pm, preferably >5 pm, are removed from the mist, via the separation of a fraction of the droplets including the largest droplets of the mist.

15. The method of any of claims 10 to 14, wherein the sterilizing solution is a solution containing hydrogen peroxide in water, preferably in a concentration of l-65mass-%, more preferably in a concentration of 16-65mass-%, even more preferably in a concentration of 30-65mass-%, most suitably in a concentration of 35-50mass-%, the method thus forming hydrogen peroxide droplets.

16. The method of any of claims 10 to 14, wherein the sterilizing solution is a solution containing ammonia, preferably as an aqueous solution, more preferably in a concentration of 10-35 mass-%, most suitably in a concentration of 25-35 mass-%.

17. The method of any of claims 10 to 15, wherein the aerosol mist is provided with an electrical charge, in order to further facilitate the mist formation, and optionally facilitate evaporation, and in order to guide the aerosol mist onto surfaces to be disinfected or decontaminated.

18. A modular system for the generation and discharge of an aerosol mist from a sterilizing solution, characterized in that it comprises a plurality of atomizing devices of any of claims 1 to 9, wherein each of the atomizing devices can be controlled together or separately with a control unit (12), thus providing the selection between the first assembly option and the second assembly option separately for each atomizing device.

19. The modular system of claim 18, comprising 2-10 atomizing devices of any of claims 1 to 9, preferably 2-5 atomizing devices.

20. Use of the atomizing device of any of claims 1 to 9, or the method of any of claims 10 to 17, or the modular system of any of claims 18 to 19, for disinfecting or decontaminating air and surfaces in a target volume.

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