GB2483552A - Method of generating a dry fog - Google Patents

Abstract

A method of generating a dry fog comprises nebulising a provided preparation and delivering it to a desired density, with particles of a predetermined size, within a predetermined time. The nebulising device preferably possesses a piezoelectric transducer 10 which nebulises the preparation / solution ideally provided in a container 6. A fan 13 may assist in delivering or dispersing the dry mist / fog, the speed of the fan being variable to control particle size and/or delivery rate. The particle size may be between 1 â 8 micrometres, preferably 1 - 2 microns. The atomised solution may be delivered by a duct 3, the length and internal shape of the duct being adjustable to control the particle size. By having atomised particles of a very small diameter, dry mist is formed. An independent claim relates to decontaminating a space by nebulising a decontaminant solution, the duct adapted to control the size of the nebulised particles.

Description

DELIVERY METHOD

The invention relates to a fast and efficient system and method for delivering a preparation to a space by means of fogging, for example a preparation for cleaning, sterilizing, sanitizing, disinfecting, decontaminating, neutralising, hydrating, feeding, sprout suppressing or other suitable uses.

It is often necessary to treat an area to destroy micro-organisms which may be pathogenic such as viruses, vegetative bacteria, spore-forming bacteria, fungi, and prions among others. In addition, it is useful to treat stored crops such as potatoes to suppress sprouting, and salads, vegetables and fruit to prevent spoilage and meat and fish to maintain hydration. Generally in all such cases a preparation may be supplied in an enclosed space and there are many well-known ways to deliver this, for example vaporising, spraying, fumigation and fogging, including mechanical fogging in agriculture, of liquid preparations. In particular ultrasonic fogging is often used in agriculture as a post harvest crop hydration system to maintain the life of living plants for some days after harvest.

Delivery methods such as fumigation and spraying are time-consuming, especially when seeking to treat areas which are difficult to access due to, for example, small size, are labour intensive, and often render the treated area unusable for an inconvenient period of time due to the potential toxicity of any lingering substances used or due to wetness or dampness following treatment.

In addition, the preparations used may be toxic and therefore problematic to transport and handle particularly in large quantities, and post-treatment residue may damage any surfaces or fabrics with which it comes into contact and/or leave residual off-gasses, all of which add to the expense. Known vaporising and fogging methods suffer similar disadvantages. A concern with known methods is that even after treatment reservoirs of micro-organisms and infection may remain, for example as bio-films and in areas which present methods find difficult or impossible to access.

According to the present invention the problems associated with the prior art are overcome by providing an improved method and system for generating, producing and delivering a cloud of dense fog within minutes that remains suspended for a suitable time, for example several minutes, after delivery.

The present invention provides, according to a first aspect, a method of generating a dry fog comprising nebulising a provided preparation, delivering the nebulised preparation to a desired density, including particles of a predetermined size, within a predetermined time.

Preferably the preparation is nebulised by a piezoelectric transducer.

Preferably the method includes assisting delivery of the nebulised preparation using a fan, in which the speed of the fan is variable to control particle size.

The variable speed of the fan may also control a delivery rate of the nebulised preparation.

Preferably the desired density provides for a visibility of 2 metres or less, 1.5 metres or less, 1 metre or less, or even 0.5 metres or less.

Preferably the predetermined size falls within the range of I -8 micrometers, 1 -6 micrometers, I -4 micrometers or even I -2 micrometers.

Preferably at least fifty percent of the particles delivered are less than said predetermined size, in accordance with Dn(50), at least seventy percent of the particles delivered are less than said predetermined size in accordance with Dn(70), or even at least ninety percent of the particles delivered are less than said predetermined size in accordance with Dn(90).

Preferably at least 70% of the particles are of said predetermined size or less, at least 80% of the particles are of said predetermined size or less, or at least 90% of the particles are of said predetermined size or less.

Preferably the predetermined time is 120 minutes or less, 90 minutes or less, minutes or less, 30 minutes or less, 25 minutes or less, 20 minutes or less, minutes or less, 10 minutes or less, or is even 5 minutes or less.

Preferably the nebulised preparation is delivered via a delivery duct, and a length of the delivery duct is varied to control delivered particle size. In addition an internal shape of the delivery duct may be adapted to control delivered particle size.

Preferably the preparation is nebulised by at least one nebulising transducer.

Preferably a variable output control is operative to adjust the volume of fog.

Preferably the number of transducers provided in each nebulising unit is varied to control the predetermined time.

Preferably the nebulised preparation delivery is assisted by an external fan.

Preferably energy provided to nebulised droplets, dependent on a fan speed, is varied to control delivered particle size. The energy, dependent on fan speed may also be varied to control a delivery of the nebulised preparation.

The present invention provides, according to a second aspect a method of decontaminating a space comprising providing a solution including a decontaminant to a nebuliser, nebulising the solution, delivering the nebulised solution to a desired density including particles of a predetermined size within a predetermined time, and further comprises directing the nebulised solution into he space by means of a delivery duct in fluid communication with the nebuliser.

Preferably the method further includes providing a further decontaminant-neutralising or decontaminating neutralising solution to the nebuliser, nebulising the further solution and directing the further nebulised solution into the space by means of the delivery duct. The further nebulised solution may be provided to the space following delivery of the decontaminating solution.

Preferably the decontaminating step, followed by a further decontaminant neutralizing step, is completed within a desired time.

Preferably the desired time is 120 minutes or less, 90 minutes or less, 60 minutes or less, or even 30 minutes or less.

Preferably the method includes removing the nebulised decontaminating solution from the space Preferably the nebulised decontaminating solution is removed from the space prior to delivery of a nebulised decontaminant-neutralizing, or decontaminant-diluting, solution.

Preferably the removed nebulised decontaminating solution is filtered and/or rendered safer during removal.

Preferably the removed decontaminating solution is collected in a reservoir.

Preferably the removed decontaminating solution is analyzed.

Preferably the nebulised decontaminant-neutralizing or diluting solution is de-humidified, removed from the space and analyzed.

The present invention provides, according to a third aspect an apparatus comprising at least one nebuliser, a container for supplying a solution to the nebuliser, a delivery duct in fluid communication with the nebuliser, the delivery duct adapted to control the size of nebulised particles of the solution delivered from the nebuliser via the delivery duct, the apparatus adapted to deliver nebulised particles of a predetermined size within a predetermined time and to a desired density.

Preferably the delivery duct has a length of greater than 2 metres, or it may have a length between 1 metre and 2 metres, or even up to 1 metre..

Preferably the delivery duct has an internal lip adjacent an end distal the container.

Preferably the delivery duct has an internal structure including a path with several direction changes. The path may be a zig-zag path.

Preferably the apparatus includes a fan. The fan may be a variable speed fan and may be operable to urge nebulised particles into the delivery duct.

Preferably the size of particles exiting an end of the delivery duct distal the nebuliser is dependent on energy imparted to the urged nebulised particles by the fan.

Preferably the nebulising means comprises at least one piezoelectric ultrasonic transducer. The apparatus may include at least 8 transducers or up to 24 transducers. Several apparatus may be used together providing more than 24 transducers to produce a dry fog.

Preferably the apparatus also includes a volume control which is variable to control the volume of nebulised particles delivered via the duct.

Preferably the apparatus may include a frame, which may have wheels and which also may have a control panel.

The delivery duct may be direct-able, in particular an end of the delivery duct distal the nebuliser may be direct-able.

The apparatus may include a further, external fan.

Preferably the apparatus includes at least one filter.

Aspects of the present invention will now be described by way of example only with the aid of the accompanying drawings in which Figures 1 (a) and (b) each show a plan view of a side of the device device in accordance with an aspect of the invention, Figures 2 (a) and (b) each show a plan view of a further side of respective devices of Figures 1 (a) and (b), Figure 3 (a) shows a plan view of a still further side of the device of Figure 1(a), Figure 3(b) shows a plan view of a still further side of the device of Figure 1(b), Figure 3(c) shows an internal structure of a delivery duct of the device of Figure 1 (a) and (b), Figure 4 (a) -(d) show the distribution of droplet sizes by volume using a full fan speed, half fan speed and no fan speed, respectively, Figure 5 (a) -(d) also show the distribution of droplet sizes by number using a full fan speed, half fan speed and no fan speed, respectively, and Figures 6 (a) -(h) show examples of experimental results relating to the efficacy of the dry fog on micro-organisms.

As can be seen from Figures 1, 2 and 3 the device 100 includes an (optional) frame or frame or chassis 110, with wheels 120, for mounting various components and a delivery duct 3.

Figure 1 (a) shows several components mounted within the chassis 110, including a piezoelectric ultrasonic nebuliser 10 containing a number of fog generating or nebulising transducers (not shown) arranged such that a container 6, which may be filled with one of, or a mixture of, a variety of suitable liquids, may provide the nebuliser with liquid to be nebulised. Other arrangements than that shown are also contemplated, for example the nebuliser and a de-humidifier may be positioned side-by-side in the chassis, or any other suitable arrangement.

Figure 1(b) shows a further example of a device in accordance with the present invention, also indicating reservoir 15 and control panel 2.

The delivery duct 3 is positioned to provide a path from the nebulisers to the outside of the device such that droplets resulting from nebulisation of the liquid may exit the device. The duct 3 is contemplated to be in fluid communication with the nebulisers.

A fan 13 is positioned adjacent the nebulisers and may be utilised to urge the nebulised liquid towards the delivery duct 3, and thence towards the room or space to be treated. A filter (not shown) may be used in conjunction with this fan.

Figures 1 (a) and (b) also show apparatus associated with a de-humidifying step which may occur towards the end of a decontaminating process, including a removable filter 5 and preferably a suction fan 11. The filter may be a simple carbon filter such as a charcoal impregnated filter, a high efficiency particulate filter (HEPA) and such like, the filter provided to clean de-nebulised, or de-humidified, air. A more complex filter may be provided should the preparation used require it, some sanitizers will need, for example, crystals, or a catalytic-type filter such as a platinum or silver catalyst or such like. Following treatment of a space air, including any debris, micro-organisms, fog, vapour, gas and/or droplets present, is drawn into this portion of the device by conventional means through the filter 5, and is turned back into a liquid by conventional means, for example by a de-nebulising and dehumidifying refrigerated coil of metal 7, which process will not be discussed further here. A further optional removable filter 4 is positioned on an opposite side of the chassis to that of filter 5. This filter may be, as discussed already, a simple carbon filter such as a charcoal impregnated filter, a HEPA filter, crystals or a catalytic-type filter such as a platinum or a silver catalyst or such like.

The chassis can include a facility (not shown) to allow for remote control of the device, such that the device can be remotely controlled to enter a contaminated area, to be positioned suitably, and to be activated to carry out required functions! The device can in addition include a robotic arm (not shown) to control the position of the delivery duct 3 to determine the direction in which any fog generated by the device is delivered, and perhaps also the time spent directing the fog to a particular location.

An optional second container 12 is also shown for use with a further liquid in a further step directed to removing active ingredients from the room or space.

During this further step the further liquid in second container 12 may be provided to the nebuliser and nebulised in a similar fashion to that employed for the contents of container 6, and similarly urged out of the nebuliser via delivery duct 3. The further liquid may include an agent which is effective in neutralising or diluting the active ingredient distributed via the nebulisation of the liquid, such as the decontaminating solution from reservoir 6. The further step may then be initiated to nebulise the contents of the optional second container 12 and either neutralize or dilute any residual active agent. At the end of the further step the room or space is left dry but with a suitable, possibly comfortable, level of humidity for use or occupation.

Figure 2 (a) shows a further side view of the device 100 including a control panel 2 for controlling device 100 and an optional panel 1 loosely covering, or providing a housing for, air/fog outlet and filter 4. Filter 4 is removable and may be selected according to need.

Figure 2(b) shows a further example of a device in accordance with the present invention, also indicating reservoir 15 and fan 13.

Figure 3 (a) shows optional panel 8 loosely covering, or providing a housing for inlet filter 5 positioned on a side surface of the device 100. A further side surface of the device 100 may also include a flap 9, which permits access to a reservoir 15 of de-humidified liquid, for example the used decontamination preparation or such like, should it be collected in a de-humidifying step. The reservoir 15 may contain means to indicate the quantity of de-humidified liquid, and concentration of active ingredient, that has been collected during the de-humidifying process. It is contemplated that the reservoir 15 may be of a shape and size suitable to receive the filter or filters so that once a preparation has been delivered and removed the filter may be placed in the reservoir of recovered preparation for storage, transport and disposal. While Figures 3 (a) and (b) show a particular arrangement of the device, no limitation is intended and the arrangement of the containers, reservoir, filters and other essential components may be varied commensurate with maintaining desired functionality.

Detectors (not shown), such as pH detectors among others, may be attached to each liquid feed and to collecting chambers, such as the reservoir 15 for de-humidified liquid behind flap 9, for monitoring and recording purposes, for example to indicate the amount of active agent distributed in, or removed from, the room or space during treatment cycles, and/or that the waste fluid is safe for disposal. A variety of parameters may be monitored, of a variety of substances, for example the preparation to be nebulised may be monitored, the collected de-humidified liquid may be monitored for example to ensure it is safe for disposal and to establish how much has been recovered, and how much residual active agent may remain in the fogged space, and/or the active agent may be monitored. The environment may be monitored during fogging and after to establish levels of hazard. The bactericidal strength of the preparation may be monitored; the amount delivered into the area to be decontaminated or otherwise treated may be monitored, as may the time the solution remains in contact with the area.

Monitoring equipment, such as for example detectors, may be provided remote from the device for measurement purposes, for example to measure the fog concentration and other useful parameters relevant to the treatment cycle. In particular some components may be positioned on an outside surface of the device, and may then deliver data to a remote location, such as a remote central location.

Figures 3 (a) and (b) further show the delivery duct 3 as a flexible hose 14 which may be used to manually direct the cloud to particular areas which may be considered difficult to access, and which are therefore potential reservoirs of micro-organisms and infection, and for which it is desired that particular care be taken. In addition the delivery duct 14 may be controlled remotely (not shown) to direct the cloud as required. Such remote control may be combined with means to remotely control the particular features of the cloud delivered in respect of particle size and such like. A camera or other such monitoring device may be present on the delivery duct to assist in such remote guidance and control.

It is known to use a piezoelectric ultrasonic transducer to produce a fog of droplets from a reservoir of liquid, in particular to produce a dry fog of droplets wherein a substantial portion of the droplets have a size sufficient to avoid wetting. In general ultrasonic foggers use a piezoelectric transducer with a resonating frequency of, for example, around I to 2 MHz, more particularly 1.4 to 1.8 MHz, even more particularly for example 1.6MHz. The delivery rate of fog produced may be controlled by, among other things, providing transducers of an appropriate number, with fans of an appropriate fan speed, and output control to produce an appropriate volume, selected according to need and application.

In the device of the present invention it is contemplated that a plurality of individual nebulising transducers (not shown) are provided with the contents of container 6 and employed to produce a cloud of droplets in which a substantial portion are of a predetermined size or less. The predetermined size may fall within the range of I -8 micrometers diameter, or within the range of I -7 micrometers diameter, or in which the predetermined size falls within the range of 1 -6, 1 -5, 1 -4, 1 -3, or even I -2 micrometers diameter. For the purposes of this arrangement between 50 -100% of the droplets are less than the predetermined size. It is contemplated in particular that droplets may have a diameter 6.31 pm or less. More particularly it is contemplated that between 70 and 95% of the droplets have a diameter of the predetermined size or less, still more particularly between 80 and 90% of the droplets have a diameter of the predetermined size or less, more particularly still in which substantially 90% of the droplets have a diameter of the predetermined size or less. This predetermined size may be of the order of 6.31 pm diameter.

One advantage of piezoelectric transducers over a mechanical device is that the fog produced is more long lasting. It is thought that the piezoelectric ultra-sonic transducers impart more energy to the droplets which therefore take a longer time to dissipate.

Droplets are urged out of the nebuliser 10 by fan 13 and into delivery duct 3.

The delivery duct length may be varied, for example to selectively reduce the number of larger droplets exiting the duct. It is contemplated that a delivery duct length of at least one metre is required to discourage droplets with a diameter greater than the desired, predetermined size to exit the duct. A longer duct allows a higher proportion of droplets of a still smaller diameter to enter the room or space to be treated. Limiting the droplet size affects the dryness of the fog containing the droplets, for example if a substantial portion of the droplets, perhaps substantially 90% or more of the droplets, have a droplet diameter of less than the predetermined size, for example but not limited to 6.31 micrometers diameter, a much dryer fog than that produced by prior art systems is created. In addition a more consistent droplet size may be produced.

The speed at which any fan operates, indicating the energy imparted to droplets by means of the fan, also influences the number and size of particles delivered, and the rate of delivery of the fog. For example a gentle fan with a low fan speed, imparting little energy, will not provide heavier droplets with sufficient energy to escape the delivery duct so that lighter droplets will predominate, the heavier droplets falling back to the reservoir. A faster fan, imparting more energy, will provide more of the heavier droplets with sufficient energy to escape the delivery duct and so more heavier droplets will be present in the fog.

The size and distribution of droplets generated by the present method therefore depends, at least in part, on the fan speed.

The end of the delivery duct 3 distal the device 100 may include an internal lip 20, shown only in Figure 3(c). The cloud of nebulised particles escaping the duct 3 behaves in many ways like a fluid, and it is known that the fastest part of a fluid stream is the central portion, thus the internal lip acts to narrow the aperture and ensure only the fastest moving particles, which are likely to include the smallest and lightest particles, escape. In addition, the lip provides a barrier for any liquid formed on the internal surface of the duct and urged towards the aperture by fan 13. This assists in reducing wetting generally.

The duct may include an internal structure which provides for a path for egress of particles of the nebulised preparation from the duct. This internal structure may include a zigzag path which the fog navigates under the influence of the fan, and it is contemplated that such a path is structured to assist in deterring particles of an undesirably large size to exit the duct. Figure 3(c) shows one such internal structure.

The device of Figures 1 (a), (b), and 2(a), (b) include a fan 13, provided to urge nebulised droplets towards delivery duct 3. Fan 13 assists in urging most droplets towards the delivery duct where the length of the delivery duct, and gravity, cause larger droplets to fall back allowing the smaller, lighter droplets of less than said predetermined size, to permeate a room or space being treated.

In the absence of such a fan such droplets find it harder to spread throughout a room or space. In a similar fashion the length of the delivery duct 3 influences the number of larger droplets, for example, those with a larger than desired diameter which can escape into the room or space being treated. It has been found that operation of fan 13 influences the distribution and range of particle sizes present in a nebulised fog.

A fan (not shown) may also be positioned outside the device to drive the fog in a desired direction in a space to be treated. This might be particularly useful in unusually -shaped spaces, for example a corridor or such like.

The effect of a fan on the size of droplets delivered following nebulisation has been investigated by passing a laser light through fog produced during nebulisation and measuring how much the beam is diffracted. Large droplets diffract the laser light less than small droplets and software can then calculate the size of droplets produced.

The spread of droplet size is set out in Table I and Figures 4 and 5. Table 1 shows the effect on particle diameter of full, half and negligible fan speeds.

Table 1. Malvern Spraytec results for water droplets produced by the Contronics HU-85 apparatus Fan Speed Time period Dn(1 O)Dn(50)Dn(90)Dv(1 O)Dv(50)Dv(90) Sauter measured pm pm pm pm pm pm Mean pm Full 3m 5s 1.58 3.14 5.41 3.43 7.92 17.96 6.50 Half 2m31s 1.85 2.93 6.31 3.27 7.53 16.49 6.16 Effectivelynil lmO9s 2.15 3.41 5.41 2.68 4.29 6.44 3.96 Effectivelynil lmOSs 2.15 2.93 5.41 2.83 4.19 8.31 4.48 The Dn(x) figures represent the diameter of a particle under which x% of the number of particles lie. For example, 10% of the particles will have a diameter under the figure for the Dn(10) i.e. in a group of 100 particle, 10 would have a diameter under the value for Dn(10). The Dv(x) is the diameter of a particle under which x% of the total volume of liquid lies. For example, if in all of the droplets measured there is a total of 100cm3 of liquid, the Dv(10) would be the upper bounding diameter of the first 10cm3 of droplets (placed in order of diameter) irrespective of how many individual droplets there are in that group.

The Sauter mean is a figure taking both volume and surface-area into account.

It is used in cases where both volume and surface-area of the droplets is important, such as combustion or evaporation processes.

Graphs 4a to 4d show the distributions based upon percentage volume for each of these sets of data, while in graphs 5a -5d the distribution is based upon particle numbers. The graphs clearly show that as the fan speed decreases, and less energy is imparted to the droplets, the distributions become more concentrated, and the 2 different distributions (number and volume) start to move closer together, and become similar. Thus a desired droplet size may be more consistently produced in the absence of a fan if other factors influencing droplet size are controlled.

There is marked change in the distribution by % volume. At full fan speed diameters range from approximately 2 -4Opm. With no fan the droplet diameters may never be more than l7pm, and in the second run may not generally exceed l3pm. This is supported by the values for Dv(50), falling from 7.9pm to 4.2pm at its lowest, and Dv(90), going from a relatively large value of 18.Opm, down to 6.4pm, as the fan speed is reduced to nothing. The distribution by numbers changes less with the change in fan speed, but the range does narrow a little.

The Sauter mean values (shown in table 1) show a clear reduction, with decreasing fan speed, in droplet diameter where both surface-area and volume are taken in to account, from 6.5pm to 4pm. As can be seen, with no fan a fog can be produced with a Sauter mean of below 4.Opm, and with a Dv(90) of 6.44pm. As can be seen, the distribution by volume is dramatically affected by the fan speed reduction, resulting in a far lower range of diameters.

It is of particular interest in the present case to produce a fog in which a substantial portion of the particles are less than a desired size, such as a dry fog, and the graph shows that with a fan set at full fan speed 90% of the particles have a size of 5.41 micrometers after around 3 minutes.

Presence of a delivery duct also influences the size of droplets delivered during the nebulisation process, a longer delivery duct having a similar effect to having no fan. This is likely due to the longer delivery duct making it harder for heavier particles to escape the duct, as in the absence of a fan such heavier particles will have less energy and be less likely to travel far, so that fewer droplets exit the duct, and generally only the smaller droplets.

Forces between droplets of the size relied upon herein, for example hydrostatic forces or perhaps electrostatic, act to urge the droplets apart, creating a vapour pressure which increases for at least a part of a cycle of treatment, helping to maintain the cloud of fog as a suspension in the air and urging droplets, vapour and gas into the most remote and difficult to access crevices of a room or space to be treated.

The present method and system generates a cloud of cold, dry fog containing droplets of a diameter, density and vapour pressure which ensures that all target areas are bathed in a suspension of droplets that exhibit fluid like behaviour, such that the droplets move randomly to fill a space or room being treated and can enter areas inaccessible to larger droplets. The range of droplet sizes and the inevitable generation of some substances in the vapour and gas states, as well as fog, ensures an efficient and comprehensively thorough delivery of the desired substance. In addition, reliance on droplets of a predetermined size such as for example but not limited to a size less than 6.31 pm diameter ensures that a smaller amount of liquid can deliver the desired comprehensive coverage of a room or space compared with prior art devices.

The presence of a fan can assist with delivery of the droplets produced to desired areas, and such a fan, or an additional fan, may be placed outside the device. A further advantage of the present method is the use of several transducers to act upon the liquid to be delivered as a cloud of fog, in particular dry fog. In particular the number of transducers used determines the time period in which a quantity of liquid may be converted into droplets of a desired size, and in which a desired vapour pressure is created within the room or space to be treated. Increasing the number of transducers converts such a quantity in a time which is significantly shorter than that achieved in prior art systems. The number of transducers can be increased to achieve a desired density of droplets of a predetermined size within a predetermined time.

The present arrangement provides for a unit sized as required, for example, a unit may include a variable number of transducers and other features providing for a device as small as a hand held device to a wheeled device for use in a very large area.

As an example, experiments show that each transducer can nebulise approximately 750 ml of liquid in 60 minutes, so a fog generator containing 8 transducers will nebulise 500 ml in 5 minutes, and so on.

The present method and system is directed to providing a cloud of fog, in particular a dry fog, of a desired density, and a desired droplet size within a desired time. The factors affecting this include varying an output control to determine the volume of fog to be delivered, varying a fan speed, varying a length of a delivery duct, and varying the number of transducers acting on the preparation to be nebulised into the fog. For example, a room or space with dimensions 3 x 6 x 2.5 meters (45 cubic meters) may be filled with a visibly dense cloud of dry fog, providing for a visibility of up to two metres, of up to one and a half metres, of up to one metre, or of up to a half a metre or less within several minutes of initiating nebulisation of 500m1 of liquid. This may include within 25 minutes, within 15 -25 minutes, within 10 -15 minutes, within 5 -10 minutes or within less time still of initiating nebulisation using a variable number of transducers. It is contemplated that a common application would use 4, 6, or 8 or more nebulising transducers, for example for up to 24 transducers or with two devices each with a selected number of transducers. This provides great advantages over known systems, which take a significantly longer time.

In addition in one typical experiment a 125 cubic metre room at ambient temperature took 10 minutes to fill to a desired density with a fog of a desired droplet size.

Rooms or spaces with larger dimensions can be filled in a desirably short time by adjusting the amount of liquid, the number of nebulisers, fan speed, delivery duct length and so on. A system including 24 transducers, or several devices each including a plurality of transducers, can extend the number of transducers and therefore the speed with which a space is filled. The time taken to fill a room or space to a desired density may be achieved by adjusting the number of transducers, as well as adjusting various parameters of the apparatus, such as fan speed.

An advantage of the present arrangement is that the dry fog forms and fills a room or space so quickly that the active ingredient can be delivered before the droplets evaporate. A problem with prior art systems is that the fog forms sufficiently slowly that delivery of the active agent is compromised, or is at least less efficient, as a significant portion of droplets evaporate before delivery can take place, or droplets are so large that they coalesce resulting in wetting. A n advantage of the present system is that very large spaces can also be filled with a dry fog and treated, for example sports stadiums and such like.

Table 2 shows sample measurements relating to room or space size, amount of solution used, number of transducers used and time taken to produce a visibly dense cloud of fog.

Table 2

Room or Volume of No Density of fog Time to fill space size soln (ltr) transducers (visibility in (minutes) (m3) used m) 0.5 8 1 5.5 2 8 1 15 As stated, the present system may be used to apply preparations to crops for example salads, vegetables or potatoes in storage or in retail stores; in a clinical environment such as a hospital; in a laboratory or containment room; or in other environments in which biological material such as micro-organisms, pathogenic material, contaminants, spoilage or other material, needs to be contained or neutralized.

Such environments could include any areas where people or animals gather for entertainment, to consume food or beverages, travel or to wait, such as for example cinemas, theatres, sports halls and stadiums, parks including amusement parks and playgrounds, schools, lecture halls, laboratories, museums, hotels, restaurants, food halls, supermarkets and other retail outlets, waiting rooms, booking halls, trains, aircraft, coaches, lorries, ships, ambulances, stations, airports, coach stations, office blocks, hotels, air-conditioning systems, hospitals, loading areas, warehouses, farms, abattoirs, any food preparation or storage areas, medical or veterinary environments, and such like. The device may be helpful in maintaining areas for burns victims, including areas where burns victims may be placed for exposure to a cool and disinfecting, and non-invasive fog.

The present system may also be used in plant propagators, for example in combination with aeroponic or hydroponic systems. The preparation provided in the fog may then be a nutrient rich solution to be provided as a fog of a desired droplet size and density to bathe the roots and/or leaves in such plant propagators. The fog may be provided for an extended period of time to reflect the need to attend to such plants during their lifetime, including feeding them.

In use, in the present device a suitable number of transducers are arranged within a shallow reservoir containing a solution, for example a decontaminating solution. The solution may include, for example, hydrogen peroxide solution, a chlorine solution, chlorine dioxide solution, formaldehyde, electro-chemically activated solution (ECAS) or electrolysed water, and/or other suitable solutions.

Use of the present method is suitable for treating, for example cleaning, sterilizing, sanitizing, disinfecting, decontaminating, neutralizing, hydrating, sprout suppressing, and/or feeding, an enclosed space such as a room, hall, a cabinet within a room, or a space such as a stadium, station or such like.

An electro chemically activated solution (ECAS) comprises an inert saline solution which is activated by electrochemical means. The activated solution is placed in the reservoir of the fogger and nebulised to produce a dry fog. When the ECAS meets with organic matter it produces the desired anti-microbial effect and reverts to a saline solution. Such a saline solution and other know decontaminants are damaging for some materials such as metals, and may be sufficiently acidic to be potentially harmful for a range of equipment. It is contemplated that the device of the present arrangement is formed from suitable material to avoid any such problems.

If the solution to be delivered is simple, for example delivery of a sprout-suppressing preparation to vegetables such as potatoes, or if levels of toxicity are acceptable or within safe exposure limits for humans or animals, the present method is suitable for an enclosed, but not a sealed, space. If the solution to be delivered is more toxic, such as hydrogen peroxide, chlorine, chlorine dioxide or such like, the present method is suitable for spaces which may be sealed to protect the environment and any persons in the area. Examples include a room in a hospital suitable for accommodating a patient, needing to be cleaned to eliminate an infection such as, for example, Methicillin Resistant Staphylococcus aureus (MRSA), or a treatment room, operating theatre or some such. The present method is also suitable for use where a still further level of isolation is needed, such as, for example, in a laboratory containment room or similar. It is contemplated that the present arrangement is also effective against Vancomycin Resistant Enterococcus faecalis (VRE), or other contaminants such as Bacillus subtilis (anthrax surrogate), Bacillus cereus (anthrax surrogate), Pseudomonas aeruginosa, or others.

Figures 6 (a) to (h) graphically show the efficacy of the dry fog method and apparatus to impact viability of micro-organisms.

In relation to a decontaminating function, during the nebulising process set out herein droplets produced from a nebulised decontaminating liquid each contain a significant proportion of the original disinfectant strength and each droplet will, on contact with a micro-organism such as for example a pathogen, deliver the active agent to the membrane of the micro-organism or directly through or across the membrane of the micro-organism. The interaction between disinfectant and micro-organism renders the micro-organism biologically inactive and kills it. The droplet may become neutralized once the active agent has been delivered.

This is an effective method of destroying micro-organisms, for example pathogenic micro-organisms, present in the air. Such micro-organisms present on surfaces are also rendered biologically inactive on contact with a droplet of the nebulised fog, however, the larger droplets of prior art systems tend to settle on surfaces during condensation or following contact and this can result in the formation of a film of liquid on the surface. Such a liquid film can create a barrier between the active ingredient and any contaminant remaining, for example a micro-organism, on the surface, in particular if the active agent has been delivered rendering barrier liquid ineffective. Such larger droplets cannot access smaller crevices, and may even block access to smaller crevices. A reservoir of micro-organisms or infection may therefore be created or remain which prior art systems cannot eradicate. In addition larger droplets tend to fall to the floor, or can be absorbed or remain on surfaces, causing them to become damp, wet and potentially damaged.

Droplets of the predetermined diameter, for example but not limited to droplets of a size less than 6.31 pm diameter, retain their integrity more strongly than larger droplets and so, while droplets in the cloud of dry fog touch all surfaces there is minimal coagulation and wetting. Any micro-organism on a touched surface will be rendered inactive by action of the decontaminant in a droplet, however such droplets will form only a layer of micro-condensation which is negligible and transient, and does not form a barrier to the action of further droplets. As a consequence further droplets may interact with micro-organisms on the surface, rendering them biologically inactive. In addition treated areas are lightly and transiently damped rather than wetted by exposure to the cloud of dry fog. Any light dampness dries out over a negligible time period leaving a treated room or space and its contents usable within a shorter period of time compared to known methods.

The smaller droplets of the present system are so light that, once they exit the delivery duct 3 of the device 100, they remain suspended in the air for several minutes without significant velocity unless directed by an external fan as required. One measure of droplet density is the reduction in visibility, and in the present system a target visibility indicating sufficient density is between 0.5 and 2 metres, for example around one metre, or more particularly around 0.5 metres, although a more dense fog with a visibility of less than 0.Smetres may be preferable. The present method and system also produces an appropriately uniform droplet density due to a broadly homogenous droplet distribution and this is apparent due to the lack of visible stratification of the droplet cloud.

Stratification of fogged clouds is common in prior art systems; however the present system has particles which, due to their small size, are not inclined to coagulate and form larger heavier droplets which cause stratification and fall to the floor to cause wetting.

Advantageously, the present method and system does not rely on heat vaporised or gas disinfectant to achieve the desired effect. In addition, the present method and system does not rely on fans in a room or space to blow the cloud of fog around or on personnel to direct fog around the room or space, in contrast with prior art systems, although such can be useful in certain cases.

It simply fills the room or space with a visible, suitably uniformly dense, ambient temperature dry fog of a suitable velocity, which is effectively still and suspended in the air for the desired treatment time and which, due not least to vapour pressure, accesses all areas including the most inaccessible crevices.

A fan system may optionally be utilized to gently agitate the cloud of fog to encourage movement of the droplets around the room or space, additionally replacing neutralized droplets with new unused droplets to encourage complete decontamination and also to further encourage the droplets into the least accessible places, and help droplets to reach all parts of irregular shaped rooms or places.

Optionally, if further and deeper de-contamination is required, especially in areas of concern or areas which are considered harder to access, a hand held device comprising for example a flexible hose or suchlike may be provided to direct additional fog gently into particular areas before or after the first main fogging process has been completed if, for example, there is concern that the virulence of the micro-organism merits this, for particularly hard to reach areas, or for more targeted decontamination of areas or personnel. A delivery duct can be provided which is a flexible hose rather than a rigid chimney to facilitate this.

At normal ambient room temperature the cold, dry cloud of fog may remain for a period of time after the nebulisers are switched off, which advantageously provides the active agents with the opportunity to be fully effective, and this period can be at least 5 minutes, and may be 10 minutes, 20 minutes, 30 minutes or more. It is expected that the room or space will have been completely decontaminated by the end of this period.

It is contemplated that the duration of a fogging step may vary. For example while a room or space may, using the current arrangement, be quickly filled with a dense dry fog to deliver a preparation, then be emptied quickly also, the fog may be retained in the room for a period of time which can in some implementations be continuous. This might be of particular value in a food storage area where it is important to retain and maintain exposure to the fog over a long period of time so that although food is delivered and then removed, all food, in the area, is exposed to the preparation. It is likely that such a preparation would be directed to suppress viral fungal, and/or bacterial growth, to suppress sprouting, and to prevent spoilage.

A further application is folia feeding as discussed above in relation to aeroponics and hydroponics.

The cycle for fogging may be adapted to reflect the particular application. For example periods of fogging may include permanent fogging for example for 24 hours per day 7 days per week; non-continuous periods of fogging, for example fogging for hours, days, weeks or months with perhaps intermittent breaks as required, alternating periods of fogging with periods without fogging, such as, for example, fogging during the night only, or during the night and weekends, including periods in which fogging with a decontaminant alternates with fogging with water, or one-off fogging instances.

Once the decontamination step has completed a further step or steps may be initiated to ensure the decontaminating solution is eliminated from the room or space, and to render the room or space safe and comfortable for use. It is contemplated that this will comprise converting the cloud of fog back into a liquid which may occur by means of the de-humidifying apparatus 7 of Figure 3(b). Air in the room or space including any remaining fog or vapour can be drawn into the device 100 through removable filter 5, behind a panel 8 and collected in a reservoir 15 container concealed behind flap 9. During the de-humidifying process visibility may return to provide approximately 50% visibility after two minutes and perhaps 75% visibility after five minutes.

It is contemplated that implementation of the present arrangement may include first providing a dry fog to a room or space, the dry fog including a preparation, followed by a second delivery of a fog including much larger droplets. The larger droplets would be urged towards the upper boundary of the fog, such as the ceiling in a room or the top of an enclosed space, and thereafter would be expected to sink to the floor or the base of an enclosed space, and during this process the larger droplets would collect' or sequester the smaller droplets of the fog ensuring they were captured and brought to the floor for later disposal.

It may be that mechanical nozzles may be useful to produce large sequestering particles for this step. In particular such mechanical nozzles can produce particles of a desired size, for example but not limited to 15 -20 micrometers, and water or a biocide or neutralizing solution can be a suitable liquid for such a sequestering step. Some of the large droplets may evaporate into gas to further neutralize or dilute any remaining decontaminant in the air.

Often it is desirable to seek to remove all traces of a decontaminating solution from a room or space, especially if the solution has some toxicity. To this effect a second container 12 is provided for a further solution, possibly a decontaminant-neutralizing or diluting solution, and once the decontaminating process has completed the process can be repeated with the further solution fogged instead of the decontaminating solution. In particular the contents of second container 12 are nebulised by means of the nebulising transducers, the droplets produced thereby being urged out of the delivery duct 3 by fan 13. The droplets of the further solution then float in suspension in the room or space acting on, or diluting or neutralizing, any decontaminating residue, to remove or render substantially ineffective any remaining active ingredient from the room or space. Any neutralizing solution used will depend on the decontaminating solution to be neutralized. If only a dilution is required this may be sterile water orsuch like.

Once the decontaminating and neutralizing steps have completed the room or space may be further treated to restore, for example, an environment comfortable for people. Any fabrics or soft furnishings will be dry, due to the absence of wetting which is an advantage of the present system and method, and the temperature and humidity may be adjusted either by the present equipment or by other means.

A particular advantage the present arrangement has over prior art systems relates to penetration of micro-organisms into materials. Different materials are penetrated to different depths by different micro-organisms and some methods of cleaning do not recognize this and do not address this problem, so that fabrics and furnishings are not decontaminated as required. The present arrangement provides for penetration of the droplets, and therefore the active agent, into materials to achieve the desired effect. Wet fog does wet the surface of such fabrics, but for reasons set out in this application do not deliver the decontaminant/biocide as required. In addition a gas will not necessarily deliver the decontaminant/biocide either. The present arrangement delivers the active agent to internal surfaces including surfaces within a fabric or furnishings as well as difficult to access surfaces of tables, chairs, beds, and so forth.

Advantageously, the device of the present invention does not require a specific temperature or humidity to be achieved in the room or space before the device is initiated, although conditioning the air appropriately is likely to reduce the time taken to completely fill a room or space with a cold, dry fog and may affect droplet size.

In use the device 100, including the number of nebulisers or units of nebulisers calculated to be necessary for the size of room or space and amount of decontaminating liquid to be used, is supplied with a container 6 filled with a liquid, for example a liquid decontaminant. A suitable filter may be provided to the device at 5, if needed, and similarly to the device at 4. The equipment is then placed within a room or space to be treated, the room or space prepared or sealed to the degree of isolation necessary, and the device switched on, remotely if necessary.

The arrangement is such that the room or space may, within a desired short period of time, such as for example 10 minutes, fifteen minutes or up to 60 minutes or such like, become imbued with a low velocity cloud or fog of droplets of a desired size, for example in which approximately 90% of droplets are of a diameter of less than 6.31 pm diameter, to a desired density, for example a density suitable to achieve a desired effect. It is also contemplated that the density may be sufficiently uniform to achieve a desired effect.

It is not necessary, but may be required, for example in a corridor or such like, to utilize fans to direct the nebulised solution or to maintain the cloud in suspension within a space to be treated or to deliver a velocity to the cloud as it is so light and fine that it simply floats in said space in a dense cloud of fog that does not coagulate to form larger droplets, condensation or wetting. The size of the droplets ensure that portions of the space that are difficult to reach are accessible to the cloud of fog and gas, and such access is further promoted by the vapour pressure and other forces, for example hydrostatic or electrostatic or similar, of the cloud of fog, and that the decontaminating action is applied to all areas even the most remote crevices.

The cloud of fog may be maintained for a desired period of time by selecting the amount of decontaminating solution provided in container 6. While the cloud will dissipate in time, once the appropriate time interval has passed the cloud of fog may be removed by initiating the de-humidifying step available in the device 100. During this de-humidifying step air, fog, vapour and gas are drawn into the device via filter 5 and collected in reservoir 15 behind flap 9. The reservoir for de-humidified solution may include the facility to measure the amount of solution recovered, and means may also be provided to further assess the recovered solution, for example the pH of the recovered solution, hold the filter, or other aspects.

A further solution may be provided in container 12, for example a neutralizing solution dependent on the decontaminant used, or a solution provided for dilution, and may then be fogged in a step to remove or otherwise cancel any effects that might result from undesirable residue of the decontaminant. This may be followed by a further de-humidifying step to return the room or space to a usable state. The room or space can then be aired and the humidity and temperature adjusted to comfort levels, or as required, using the device or other means before allowing access back into the room or space.

Advantageously, the system and method set out is safe and effective on a range of surfaces common to the environments that are likely to be treated, such as stainless steel, vinyl, Formica, fabric, soft furnishings, carpets and sensitive electronic equipment. As the droplets attain ambient temperature they do not significantly condense on equipment or furnishings but do form a fine layer of micro-condensation which generates a negligible and transient dampness but no wetting. As a consequence, the system and method is unlikely to adversely effect or harm electrical fittings, sensitive electrical equipment, including but not limited to cardiac monitoring equipment, scanning equipment, computers, and such like. However, it may be appropriate for extremely sensitive electronic equipment to be switched on or off during treatment.

The present system and method has a further advantage over prior art systems that a 4 -6 log reduction of micro-organisms is achievable with a lower concentration of disinfectant that is less toxic and harmful to humans and other mammals (for example in a hospital or veterinary hospital environment).

In addition, the present system and method uses much smaller volumes of liquid solution to treat large spaces compared to prior art systems, therefore safety is enhanced as large quantities of decontaminating liquid do not need to be transported by vehicle or by people, and also potentially a lower and therefore safer concentration of decontaminant may be used, resulting in a system which has less toxic and less corrosive potential than existing fogging, vapour or gas decontamination systems. Containers for decontaminating solutions or for neutralizing solutions may be transported and used in sealed containers to reduce hazard, if needed. Alternately, or in addition, ECAS or other suitable preparations may be made on site, or purchased in variable quantities in variably sized containers, or a reservoir may be available on site to store suitable preparations for use.

The present system and method includes a cycle of treatment which bathes a room or space in a cloud of nebulised solution, for example a decontaminating solution, for a sufficient time and with a sufficient penetration into remote crevices to effectively decontaminate all areas and surfaces. The decontaminating dry fog may then be removed and a further nebulising step, in which a decontaminant-neutralizing solution is nebulised to neutralize or dilute the decontaminant, or the active agent in the decontaminant, in the room or space. The room or space may finally be rendered habitable or otherwise usable, in a very short time compared with prior art arrangements, A further useful application of the present arrangement is in feeding plants or vegetation. Nutrients are placed in the reservoir in a suitable form for delivery and the device placed in a food storage area such as a food transporter, for example a lorry or the hold of a ship, warehouse, cold store or retail outlet. The device is then activated to generate a dry fog in which the active ingredient in the preparation is the nutrient or nutrients. The nutrients may then be absorbed by the plants or vegetation through, for example, stomata. This can extend the shelf-life of plants and vegetation.

The present apparatus and method is capable, in one unit, to quickly deliver, monitor, remove and record the application of a dense dry fog including an active agent into a space, and remotely report to a central location. The space can include, but is not limited to, a secure space such as a patient room, an operating theatre and such like, and is contemplated to cover the range of uses set out elsewhere in this document. In addition the apparatus is capable of recording, among other things, the strength of the solution delivered, the contact time in the space, and other useful data, and is also capable of providing for the removal of the active agent from the space.

It is contemplated that this apparatus and method is particularly useful for applications where decontaminating and such like functionality is required but the treated space is use-intensive, such as in a hospital environment where a hospital room or operating theatre may be needed for urgent re-use once a thorough cleaning process has completed. The present arrangement provides for a desirable turn-around time in the region of, for example, two hours, or preferably within a time of for example one hour, or for example 30 minutes or less. Within this timescale a decontaminant may be delivered to the room or space, to a density and with a particle size that very difficult to access areas are exposed to the decontaminant, the room or space cleared of the dry fog, filled again with a decontaminant-neutralizing or diluting fog and cleared again, the dry fog in each stage ensuring that the room or space is not wetted or damp following these steps but is suitable for use very promptly.

It is also to be noted that desirable droplet size will depend on environmental temperature and humidity and if wetting is desirable or not.

For general decontamination of rooms containing sensitive electronic equipment, paperwork, computers etc, it will be desirable to avoid wetting.

Therefore a small droplet size will be preferable.

For deep cleaning of highly contaminated areas, perhaps containing biofilms (thick layers of microbial colonies), more wetting may be required, which may be achieved through an increased volume of fine droplets or a smaller volume of larger droplets.

It may be more effective to deliver different biocides in different droplet sizes depending on the mechanism of action of that biocide. For example, a layer of wetting over the target micro-organism may prevent some biocides reaching the target micro-organism, whereas other biocides may be more effective if applied as a thicker layer of solution to the target micro-organism.

For more complex environments with smaller harder to reach crevices, smaller droplet sizes would be preferable.

For decontamination of personnel, larger droplets may be preferable if wetting is required for more efficient decontamination or if smaller droplets carry a risk on inhalation.

Decontamination of warm environments may require larger droplet sizes to reduce the effects of evaporation. Larger droplets will be more resistant to evaporation such that they may reduce in size but not vaporise.

A combination of smaller and larger droplets may also be desirable. If the environment harbours a high organic loading or large numbers of aerosolised microorganisms in suspension, it may be appropriate to have a first cycle that delivers a biocide with small droplet sizes to destroy the microorganisms. This would be followed by a second cycle to deliver larger droplet sizes to create a blanket of larger droplets that may sequester the smaller droplets and remove them from suspension by drawing them towards the floor.

In addition a low humidity environment may require a longer cycle time to raise the relative humidity prior to treatment, in order to remove the effects of evaporation prior to treatment.

It will be appreciated that the present invention is not restricted to the details of the foregoing examples. For example the foggers are not necessarily limited to piezoelectric ultrasonic foggers but can be any kind of ultrasonic fogger or nebuliser which can produce droplets of a desired size. Flexible delivery duct 14 may be provided instead of or in addition to rigid delivery duct 3. The delivery duct is shown positioned at the top of the device, adjacent the reservoir 6 containing a treatment or sanitising solution, however the reservoir position is not limited to the top of the chassis and may be positioned anywhere, indeed positioning the reservoir towards the base of the chassis may allow a portion of the delivery duct to be enclosed within the chassis, reducing the external size of the device, or allowing even smaller droplets to be delivered, for example by increasing the length of the delivery duct.

The number of nebulisers may be adjusted to reflect the room or space to be treated, and if the room or space is sufficiently large more than one device may be utilised to obtain the desired effect. Filter 4 may be positioned on a suitable side of the device, with filter 5 on an alternative side.

Detectors may be used, both within the machine or externally, for example to confirm whether or not levels of active ingredients in the environment have returned to safe exposure levels or to monitor the concentration to be delivered, and these detectors may include pH detectors, as indicated, and also hydrogen peroxide, chlorine, and chlorine dioxide detectors among others.

Although the specification refers to a decontaminating solution' in places, it is intended to be understood that any desired or suitable solution may be used.

The system and method disclosed is contemplated to be suitable for additional applications, for example de-fleaing dog kennels, disinfecting animal welfare centres, farm enclosures, stables for horses and other areas, veterinary surgeries, GP surgeries or sports facilities, or other uses including those set out earlier.

It is contemplated that the device and arrangement proceeds without a fan to urge the droplets towards the delivery duct.

It is contemplated that a variable number of transducers may be used for any arrangement as required.

It may be that some wetting occurs adjacent the base of the device during operation.

Claims (42)

1. CLAIMS1. A method of generating a dry fog comprising: nebulising a provided preparation; delivering said nebulised preparation to a desired density, including particles of a predetermined size, within a predetermined time.
2. 2. A method as claimed in claim 1 herein said preparation is nebulised by a piezoelectric transducer.
3. 3. A method as claimed in claim 1 or claim 2 wherein said method includes assisting said delivery using a fan, and wherein a speed of said fan is variable to control particle size and/or to control a delivery rate of said nebulised preparation.
4. 4. A method as claimed in claim 1, 2 or 3 wherein said desired density provides for a visibility of 2 metres or less, or wherein said desired density provides for a visibility of 1.5 metres or less, or wherein said desired density provides for a visibility of 1 metre or less, or wherein said desired density provides for a visibility of 0.5 metres or less.
5. 5. A method as claimed in any of the preceding claims wherein said predetermined size falls within the range of 1 -8 micrometers, or wherein said predetermined size falls within the range of 1 -6 micrometers, or wherein said predetermined size falls within the range of 1 -4 micrometers or wherein said predetermined size falls within the range of 1 -2 micrometers.
6. 6. A method as claimed in any of the preceding claims wherein: at least fifty percent of the particles delivered are less than said predetermined size, in accordance with Dn(50), or wherein at least 70 percent of the particles delivered are less than said predetermined size in accordance with Dn(70), or wherein at least ninety percent of the particles delivered are less than said predetermined size in accordance with Dn(90).
7. 7. A method as claimed in any of one of claims 1 -6 wherein at least 70% of the particles are of said predetermined size or less, or wherein at least 80 % of the particles are of said predetermined size or less, or wherein at least 90% of the particles are of said predetermined size or less.
8. 8. A method as claimed in any one of the preceding claims wherein said predetermined time is 120 minutes or less, or wherein said predetermined time is 90 minutes or less, or wherein said predetermined time is 60 minutes or less, or wherein said predetermined time is 30 minutes or less, or wherein said predetermined time is 25 minutes or less, or wherein said predetermined time is 20 minutes or less, or wherein said predetermined time is 15 minutes or less, or wherein said predetermined time is 10 minutes or less, or wherein said predetermined time is 5 minutes or less.
9. 9. A method as claimed in claim 1 wherein said nebulised preparation is delivered via a delivery duct, and a length of said delivery duct is varied to control delivered particle size, and/or an internal shape of said delivery duct is adapted to control delivered particle size.
10. 10. A method as claimed in claim I or claim 2 wherein said preparation is nebulised by at least one nebulising transducer, and wherein a variable output control is operative to adjust the volume of fog.
11. 11. A method as claimed in claim 10 wherein the number of transducers provided in each nebulising unit is varied to control the predetermined time.
12. 12. A method as claimed in claim 1, 2 or 3 wherein said nebulised preparation delivery is assisted by an external fan.
13. 13. A method as claimed in claim 12 wherein energy provided to nebulised droplets, dependent on a fan speed, is varied to control particle size and/or to control a delivery rate of said nebulised preparation.
14. 14. A method of decontaminating a space comprising: Is providing a solution including a decontaminant to a nebuliser; nebulising said solution; delivering said nebulised solution to a desired density including particles of a predetermined size within a predetermined time, further comprising directing said nebulised solution into said space by means of a delivery duct in fluid communication with said nebuliser.
15. 15. A method as claimed in claim 14 further comprising: providing a further decontaminant-neutralizing solution to said nebuliser; nebulising said further solution; directing said further nebulised solution into said space by means of said delivery duct, wherein said further nebulised solution is provided to said space following delivery of said decontaminating solution.
16. 16. A method as claimed in claim 15 wherein a decontaminating step, followed by a further decontaminant neutralizing step, is completed within a desired time.
17. 17. A method as claimed in claim 33 wherein said desired time is 120 minutes or less, 90 minutes or less, 60 minutes or less, or 30 minutes or less.
18. 18. A method as claimed in claim 14 or 15 wherein: said nebulised decontaminating solution is removed from said space and/or said nebulised decontaminating solution is removed from said space prior to delivery of said nebulised decontaminant-neutralizing, or decontaminant-diluting, solution.
19. 19. A method as claimed in claim 18 wherein said removed nebulised decontaminating solution is filtered and/or rendered safer during removal.
20. 20. A method as claimed in claim 18 or claim 19 wherein said removed decontaminating solution is collected in a reservoir.
21. 21. A method as claimed in claim 20 wherein said removed decontaminating solution is analyzed.
22. 22. A method as claimed in claim 15 wherein said nebulised decontaminant-neutralizing solution is removed by a de-humidifying step and analyzed.
23. 23. An apparatus comprising: at least one nebuliser; a container for supplying a solution to said nebuliser; a delivery duct in fluid communication with said nebuliser, said delivery duct adapted to control the size of nebulised particles of said solution delivered from the nebuliser via the delivery duct,: said apparatus adapted to deliver nebulised particles of a predetermined size within a predetermined time and to a desired density.
24. 24. An apparatus as claimed in claim 23 wherein the delivery duct has a length of greater than 2 metres, or wherein the delivery duct has a length of between 1 metre and 2 metres, or wherein the delivery duct has a length up to 1 metre.
25. 25. An apparatus as claimed in any of the preceding claims wherein said delivery duct has an internal lip adjacent an end distal said container.
26. 26. An apparatus as claimed in any one of the preceding claims wherein said delivery duct has an internal structure including a path with several direction changes.
27. 27. An apparatus as claimed in claim 26 wherein said path is a zig-zag path.
28. 28. An apparatus as claimed in any one of the preceding claims including a fan.
29. 29. An apparatus as claimed in claim 28 wherein said fan is a variable speed fan.
30. 30. An apparatus as claimed in claim 28 or claim 29 wherein said fan is operable to urge nebulised particles into said delivery duct.
31. 31. An apparatus as claimed in claim 49 wherein the size of particles exiting an end of said delivery duct distal said nebuliser is dependent on energy imparted to said urged nebulised particles by said fan.
32. 32. An apparatus as claimed in claim 31 wherein said nebulising means comprises at least one piezoelectric ultrasonic transducer.
33. 33. An apparatus as claimed in claim 32 wherein said apparatus includes at least 8 of said transducers, or wherein said apparatus includes at least 24 of said transducers.
34. 34. An apparatus as claimed in claim 32 wherein said apparatus includes a plurality of units each comprising at least one nebulising transducer.
35. 35. An apparatus as claimed in any one of claims 23 to 34 wherein a volume control is provided, said volume control variable to control the volume of nebulised particles delivered via the duct.
36. 36. An apparatus as claimed in any one of the previous claims further including a frame, and/or wherein the apparatus has wheels
37. 37. An apparatus as claimed in any one of claims 23 to 36 including a control panel.
38. 38. An apparatus as claimed in claim 23 wherein said delivery duct is flexible.
39. 39. An apparatus as claimed in claim 38 wherein an end of said delivery duct distal said frame is directable
40. 40. An apparatus as claimed in claim 23 including a further container for supplying a solution to said nebuliser.
41. 41. An apparatus as claimed in claim 28 including a further, external, fan.
42. 42. An apparatus as claimed in claim 23 further comprising at least one filter.