Sanitisation method

Abstract

A method for sanitising agricultural buildings or space 100 comprises sealing external doors 106, windows 104 and other openings to reduce airflow from the building or space 100. A source of sanitiser is then provided within the building 100 through at least one of a pumped source fluid release system or locally applied sanitiser to particular areas. One or more fans or other air sources are arranged to drive air into the building or space 100 to provide a positive pressure therein with respect to the pressure outside the building or space 100. Preferably the sanitisation fluid contains formaldehyde. In one embodiment, the building 100 has at least one ventilation fan 110, 112, 114 which are switchable between moving air into the building 100 and moving air out of the building 100. There may also be one or more sanitisation fluid sensors 118 within the building 100 as well as outside of the building 100, wherein the sensors may control the operation of the fluid release system. When the sanitiser is applied locally to particular areas, the sanitiser may be sprayed or painted.

Description

The present invention relates to the field of sanitisation systems, methods and processes, as may be employed typically in agricultural environments, but also in other environments where containment, reduction and / or elimination of microbial growth is desired. It relates more particularly to the dispensing of sanitising fluids within such environments. Buildings, such as barns, sheds etc. are often used in agriculture to house livestock, such as cattle, sheep, or pigs, or poultry etc. These buildings are typically large, and may be designed to hold hundreds, or even many thousands of animals, particularly when housing poultry. These buildings are in need of sanitisation at intervals for general hygiene purposes, and to maintain the health of the animals inside. There are existing systems for carrying out such a sanitisation process. One convenient way of sanitising these buildings comprises introducing a sanitising product in gas, vapour or liquid form, which then spreads throughout the environment by natural and forced convection, typically from existing ventilation fans. This is traditionally done by generating a quantity of an appropriate vapour or liquid spray in an enclosed space, where the quantity of vapour to be used is estimated based upon the volume of the space to be treated. The vapour then disperses around the building, sanitising on contact, where the chemical content of the sanitiser is above some threshold level in the atmosphere. This is described for example in UK patent GB2565335B, the contents of which are incorporated by reference. Typically, the buildings used to house animals may be built from metal panels, or have some other panellised construction, such as concrete panels. Alternatively, they may be built with brick or blockwork. Also, they tend to have various fixtures and fittings therein, such as pens, cages, fences etc. All of these things introduce nooks, niches, recesses, gaps etc. that can impede the ingress of the sanitisation vapour during a sanitisation cycle, which in turn tends to leave some areas untreated. Although it’s not practically realistic to be able to achieve total 100% coverage of all surface areas, including in every recess etc. in a large and complex building, clearly it is better to be able to treat as much as possible, to delay the need for future sanitisation cycles. According to a first aspect of the present invention there is provided a method for sanitising an agricultural building or space, the process comprising the steps of: a) sealing external doors, windows and other openings to reduce airflow from the building or space; b) providing a source of sanitiser within the building, through at least one of i) a pumped source fluid release, or ii) locally applied sanitiser to particular areas; c) arranging one or more fans or other air sources to drive air into the building or space to provide a positive pressure therein with respect to the pressure outside the building or space; Embodiments of the invention therefore provide a solution to the problem of how to more effectively, or more efficiently, provide a sanitisation cycle to the small areas that are often missed by traditional methods of application of the sanitisation fluid. By ensuring a positive pressure within the building, the fluids within the building will tend to be driven into these small areas, such as cracks, recesses or gaps etc, particularly those that have a fluid passage through to a region that is not being positively pressurised, such as outside the building or into areas of the building not being treated, so aiding the sanitisation of the harder to reach areas within the building. In effect, in such situations, the sanitisation fluid is effectively being blown into such recesses. Some embodiments may comprise just a locally applied sanitiser in particular areas, these typically being the cracks and recesses etc. Other embodiments may employ just a pumped source fluid release system, where the fluid typically comprises of a vapour, and where the pumped source may be arranged to release the fluid in one or more areas of the building or space, and convection currents from the fan(s) are used to disperse the fluid inside the space. Other, preferred embodiments may employ both the pumped source and the locally applied sanitiser. The application of sanitisation fluid directly to areas within the building where there are any recesses, gaps, cracks or the like may be done by means of spraying, painting, or some other means of application, as would be appreciated by the normally skilled person. Thus, where this is done, the additional concentrate of sanitisation fluid helps to achieve a high penetration of sanitisation fluid at sufficient strength to be effective. The application of sanitisation fluid directly in this manner may be carried out by a manual process of spraying or painting the sanitisation fluid into the recesses, gaps, cracks etc. Alternatively, or as well, the additional step of spraying or painting the sanitisation fluid into the recesses, gaps, cracks etc may be carried out by a remotely controlled spraying device. This may be a wheeled or tracked device able to move around the building, and which may carry a quantity of sanitisation fluid and application means, such as a sprayer, brush, etc. Some embodiments of the invention therefore provide for a reduction in the uncontrolled release of sanitiser into spaces neighbouring the one being treated. As will be explained further herein, the use of sensors external to the space being treated allow a finer degree of control of the quantity of sanitisation fluid that escapes from the building, or other target environment or space being treated. Embodiments also allow for the reduction in the use of sanitiser as is often done in prior art methods, where excess sanitiser is often employed in the hope that it reaches into the recesses etc. Advantageously, in some embodiments of the invention, the method is carried out on a building having at least one ventilation fan as a permanent installation, and step (c) is carried out, at least in part, by arranging the ventilation fan to drive air into the building. This takes advantage of previously installed ventilation fan(s) where the direction of airflow of the fan(s) can be controlled. Advantageously, one or more fans may be used to introduce a positive pressure within the space being treated, as these are frequently already in place. Alternatively or as well, other pressure sources, such as compressed air, may be fed into the space to provide the positive pressure. Conveniently, in some embodiments, the fan is wired to be switchable between a state where it moves air into the building, and a state where it moves air out of the building. The fan may be already so wired, or it may be wired retrospectively to provide this functionality, where the physical and electrical arrangement of the fan so permits. Advantageously, some embodiments of the invention comprise a further step of arranging one or more sanitisation fluid sensors outside of, but in proximity to the building, and a yet further step of measuring the concentration of sanitisation fluid at the sensors, and using the measurement to control the operation of the fluid release system. By arranging the sensors around the outside of the building, the leakage of the sanitising fluid can be detected, which gives an idea as to how complete the sanitisation process is. Such measurements can be used to control how much further sanitiser should be used, and so helps to minimise or reduce the amount of sanitiser used in the sanitisation process. Advantageously, in some embodiments further sensors may be arranged within the building, and the measurements from these further sensors used to control the operation of the fluid release system. These additional measurements provide an indication of how the sanitising fluid is spreading through the building. They therefore provide information that may be used to control the emission of sanitiser in different parts of the building, e.g. by control of different sanitiser emission valves etc. Preferably, the one or more fluid sensors and the fluid release system may be connected to a computer system, the computer system being arranged to control the fluid release system based upon the measurements taken from the one or more sensors. The computer system therefore allows a fine degree of control over the release, based upon measurements made from outside the building, and also inside if sensors are also present there. Advantageously, the sensors located outside the building may be placed at locations where any fluid flow paths, such as from gaps, cracks etc. are expected or known to be. Thus, they may measure leakage caused by the positive pressure within the building forcing out sanitiser fluid through the gaps. This gives an indication of the sanitiser fluid flow within the gaps, and so how well the sanitiser has penetrated the building. It also gives an indication of how much sanitiser is escaping from the building being treated. The fluid release system may comprise of one or more valves, nozzles, pumps, fluid containers etc. connected by appropriate pipes, wherein the pumps, nozzles and / or valves may be controllable by the computer system. The computer system may be arranged to change sanitiser flow rates of any release valves if the sensors indicate that either too little or too much sanitising fluid is making its way outside of the building or space being treated. There may be, in some situations, a desired minimum leakage quantity to be detected, that is indicative of penetration of sanitiser fluid into the cracks, orifices or recesses etc. The sensors may indicate the leakage directly, or the computer system may be arranged to estimate leakage based upon readings from external and / or internally located sensors, and other factors such as internal and external air pressures, sanitiser flow volumes etc. The computer system may have pressure measurement devices connected thereto, allowing air pressure to be measured both internally and externally to the building or space being treated. The computer system may be arranged to control the release valves dependent upon the readings from the pressure measurement devices. For example, it may be arranged not to switch on the release valves until a positive pressure, with respect to external pressure, has been achieved within the building being treated. The sanitiser sensors may be any suitable sensor for providing an indication as to the concentration of sanitiser within the atmosphere. Advantageously, in some embodiments the sensors may be electrochemical cell sensors. In a typical installation of an embodiment of the invention, there may be multiple sensors and multiple release valves controlling the release of sanitisation fluid. The sensors may be connected to the computer system by a wired, or a wireless system. For example, a radio connection may be used to provide communication between the sensor and the computer, or from one sensor to another, forming a network of connected elements. Such a network may of course be formed using wired connections, such as by using ethernet cables etc. The valves (including any dispersion nozzles attached or associated therewith) and / or pumps may be similarly connected in a wired, or wireless fashion to the computer system. In some areas where an embodiment of the method of the invention is being used, the building being treated may not have any, or a sufficient number of fans for providing a flow of air into it. Conveniently, in such cases at least one temporary fan may be arranged to blow air into the building in addition to any permanently installed fans. The temporary fans may be located where convenient, such as in windows or vents,, or located externally and coupled to the building with ducting. Advantageously, the sanitising fluid may be an organic compound. Advantageously, the sanitising fluid may be an aldehyde. Advantageously the sanitising fluid may be a formaldehyde based sanitiser. The sanitiser may be Formalin, or a similar product. Other sanitisation fluids may be used, that contain other active ingredients, as would be appreciated by the normally skilled person. The sensors used to detect the sanitisation fluid will be selected according to the fluid being used, as would again be understood by a normally skilled person. Note that references to a building herein may refer to just a part of a building, where other parts of the building are not being treated. Thus, any reference to, e.g. sensors being deployed outside the building may refer to just that part of the building being treated, and may thus be located inside other parts of the building, or may be completely outside of said building. Embodiments of the invention are further described hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figure 1 diagrammatically illustrates a typical environment where an embodiment of the method of the invention may be used, along with an installation of fans and sensors; Figure 2 diagrammatically illustrates the effect of a positive pressure on one side of a building wall compared to the other, and how it improves sanitiser penetration; and Figure 3 diagrammatically illustrates the use of localised application of a sanitiser on a recess in a wall. Shown in Figure 1 is an agricultural building, shown representationally, that is arranged to be sanitised using a process according to an embodiment of the present invention. A building 100 is shown in plan-view and comprises of a rectangular external wall 102, with windows 104, and doors 106. The building 100 has various internal walls 108. Buildings such as these, of different designs, but having a similar basic structural elements, are commonly used in agriculture to house cattle, chickens or other animals, either on a temporary or permanent basis. Such buildings are prone to bacterial infection over time, and hence need to be sanitised at regular intervals. Building 100 is shown being set up for a sanitisation cycle according to an embodiment of the present invention. The building has installed fans 110, 112, 114 which are, when the building is not in a cleansing cycle, set to extract air from the building, to provide cooling and fresh air to the animals within. During this process, air would be drawn in through cracks and gaps in the doors, windows, and vents that are present in such buildings. In preparation for sanitisation, the building will have installed within it a sanitisation release system, comprising of fluid tanks and pumps (not shown) and release valves 116, positioned so as to provide sanitiser in a mist or vapour into the environment within the building, on demand. The pumps and release valves are connected to a central computer system 117 that is able to activate them under software-automated, or manual control. Around the building are located a series of electrochemical sensors 118, designed to sense the presence and quantity of sanitiser in the air. The sensors are preferably located at areas where there are known, or suspected gaps which will let air pass out of the building when the fans are activated. These sensors 118 are also connected to the computer system, and act to provide information relating to leakage of sanitiser from the building. The sensors 118 and release valves 116, along with the associated pumps etc. may be connected to the computer system 117 by any suitable means. They may be connected wirelessly, or with a wired connection. The computer system is arranged to receive inputs from the sensor(s), to process inputs therefrom (and other related data) and provide outputs to the release valves 116. Thus, it also includes a processor, memory, and any such input and output hardware to enable the input and control of such things, including, dependent upon the elements making up a particular embodiment, analogue to digital conversion means, switching means, which may comprise solid state and / or relay switches. The computer system 117 may comprise a Supervisory Control and Data Acquisition (SCADA) system. Sensors 118 suitable for use in embodiments of the invention are manufactured by www.draeger.com, although other manufacturers also provide suitable sensors. In most environments, other sensors (not shown) will be located within the building also, to provide a measure of coverage in different parts thereof. The outputs of the sensors, both internally and externally located provide the computer with information on which of the valves 116 should be activated, so as to provide as complete a sanitisation cycle as possible whilst also lowering wastage, or decreasing over-use of sanitiser where it’s detected. The internal sensors may be used to ensure that the level of sanitiser released into the atmosphere stays within desired or prescribed limits. If the sanitiser levels go too high within the building then the valves releasing the sanitiser fluid may be shut off or set to provide a reduced flow rate, until a desired amount is present. The levels of sanitiser within the building may be maintained at certain levels, and / or for a certain time, to allow the sanitiser to pass through the various gaps etc. and to be detected by the externally located sensors. The thresholds for deciding when a sanitisation cycle is complete may be decided by prior experience or measurement. An additional, temporary fan 120 is also shown installed in a window, as may be done where it is judged that there is insufficient capacity available from any permanently installed fans, given an estimate of the degree of leakage that would occur. The number of fans to be used may be judged based upon experience of the operator, or may be determined based upon measurements of pressure within and outside the building, with a number of fans activated. An early step in the sanitisation cycle is the spraying of any cracks and small recesses that are found within the building. This may be done in any convenient fashion. Typically, a person with breathing apparatus may enter the building and spray it manually. Alternatively, a remote controlled sprayer may be used to avoid the risk to personnel. By spraying the cracks and recesses, it increases the chances of penetration of the cracks and recesses by the sanitiser when the positive pressure is produced in the building by the fans. Prior to the fans being activated, the doors 106, window 104 and significant vents etc. are sealed up to minimise leaks though those exits. Smaller vents may be left open, where doing so will not compromise the ability to produce a positive pressure in the building, but it is preferable to close larger ones so that air will tend to get forced through and out of the smaller ones under the positive pressure generated by the fans. In large agricultural buildings it is impractical to be able to seal the building completely, and indeed it is undesirable to do so. Leakage through small gaps ensures that those small gaps, which can be hard to get at using traditional sanitisation methods, get a quantity of sanitiser applied to them as the fans are activated during the sanitisation process. The sealing of doors and windows etc. may be done in any suitable manner - merely closing the doors and windows may be enough, assuming there are not large gaps left under doors etc. In an initial phase of the sanitisation cycle, the fans 110, 112, 114, 120 are all switched to blow air into the building. At the same time, sanitiser is released, in quantities controlled by the computer system by suitable operation of pumps and valves 116. The sensors present within the building are monitored to ensure that all areas get a minimum quantity of sanitiser. The sensors external to the building are used to ensure that the gaps which they are monitoring allow some degree of sanitiser to pass therethrough during the sanitisation cycle. This ensures that the gaps being monitored are sanitised. Other gaps present that do not have an associated sensor located adjacent to them will also likely get a degree of sanitisation, but it will not be known how much. However, the positive pressure system within the building, according to embodiments of the invention, mean that the sanitisation achieved is likely to be greater than would occur with prior art methods of sanitisation. In the example given above, the permanently installed fans were able to be driven in reverse, so as push air into the building. Where it isn’t possible to do this, or where it is impractical to reconfigure the fans to do so, then the fans may be sealed off and the positive pressure within the building generated by just the use of temporary fans, or compressed air piped etc. Figure 2 shows in more detail how sanitiser can penetrate into a crack or recess in a wall when a method according to an embodiment of the invention is employed. It shows a wall 200 of a building, but might equally represent a partition, or a join between a wall and a roof or ceiling, or a roof, etc. The wall is not shown to scale. The wall has a crack or recess 201 that penetrates through the wall and out to a region not being treated, which may be outside, or may be another part of the building being treated. An inside surface 202 of the wall 200 is on the right of the wall, whilst an outside surface 204 of the wall is on the left. Here, a positive pressure has been built up within the building by activation of fans, as described in relation to Figure 1, the positive pressure being indicated by the “+” signs, resulting in a relative lower pressure outside the building, as indicated by the signs. There will thus be an airflow through the recess of the wall as indicated by the arrow passing through the recess 201. If any sanitiser has been released through a release valve inside the building then it will be in the air, and also passing through the recess 201. Thus, the inside surfaces 206 of the recess will get a better chance of exposure to sanitiser than if a positive pressure is not employed. Figure 3 shows an approach that may be used alongside that shown in Figure 2, or instead of it. Again, a wall having a recess is shown, and like reference numerals represent like elements. Prior to activation of fans to create a positive pressure within the building being treated, a sanitising fluid has been applied to a region where a recess is known to exist. This would ideally be done for all recesses that are known in the space being treated, but clearly will have efficacy if a reduced number are treated in this manner. Once the sanitising fluid 208 has been applied, then a positive pressure can then be generated by activation of the fans. This pressure then acts on the sanitiser around the recess to at least partially blow it through the recess 201, to sanitise the inner parts 206 thereof as before. Although the examples given above relate to the invention being employed to sanitise buildings arranged to hold animals, the invention is also applicable to other buildings where fumigation may be required, such as grain or feed stores etc. The functions described herein as provided by individual components could, where appropriate, be provided by a combination of components instead. Similarly, functions described as provided by a combination of components could, where appropriate, be provided by a single component. Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. Features, integers, characteristics or compounds, described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

Claims

1. A method for sanitising an agricultural building or space, the process comprising the steps of:5          a) sealing external doors, windows and other openings to reduce airflow from thebuilding or space;b) providing a source of sanitiser within the building, through at least one of i) a pumped source fluid release system, or ii) locally applied sanitiser to particular areas;c) arranging one or more fans or other air sources to drive air into the building or 10 space to provide a positive pressure therein with respect to the pressure outside the building or space; andd)) arranging one or more sanitisation fluid sensors outside of, but in proximity to the building or space, and a yet further step of measuring the concentration of sanitisation fluid at the sensors, and using the measurement to control the operation of the fluid15 release system.

2. A method as claimed in 1 wherein the method is carried out on a building having at least one ventilation fan as a permanent installation, and step (c) is carried out, at least in part, by arranging the ventilation fan to drive air into the building or space.

203. A method as claimed in claim 2 wherein the ventilation fan is wired to be switchable between a state where it moves air into the building, and a state where it moves air out of the building or space.25   4. A method as claimed in any of the above claims wherein further sensors arearranged within the building or space, and wherein measurements from these further sensors are also used to control the operation of the fluid release system.

5. A method as claimed in any of the above claims wherein, when a pumped source 30 of sanitiser is used, the one or more fluid sensors and the fluid release system areconnected to a computer system, the computer system being arranged to control the fluid release system based upon the measurements taken from the one or more sensors.

6. A method as claimed in claim 5 wherein one or more pressure measurement35 devices are arranged to measure air pressure inside and / or outside the building or space.27 06 247. A method as claimed in claim 6 wherein the computer is arranged to control the fluid release system dependent upon measurements taken from the pressure measurement devices.5   8. A method as claimed in any of the above claims wherein, when sanitiser isapplied locally to particular areas, the additional step is carried out by a manual process of spraying or painting the sanitisation fluid into the particular areas.

9. A method as claimed in any of claims 1 to 7 wherein, when sanitiser is applied10 locally to particular areas, the additional step of spraying or painting the sanitisation fluid into the particular areas is carried out by a remotely controlled spraying device.

10. A method as claimed in any of the above claims wherein at least one temporary fan is arranged to blow air into the building or space in addition to any permanently15 installed fans.

11. A method as claimed in any of the above claims wherein a source of compressed air is arranged to feed air into the building to create the positive pressure therein.20   12. A method as claimed in any of the above claims wherein the sanitisation fluidcontains formaldehyde.

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