GB2602789A

GB2602789A - Air sterilisation system for room or zone

Info

Publication number: GB2602789A
Application number: GB2020166.1A
Authority: GB
Inventors: Coles Richard
Original assignee: Stratify Ltd
Current assignee: Stratify Ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2022-07-20
Also published as: GB202020166D0

Abstract

An air sterilisation system 200 comprising: at least one inlet 204 for allowing ingress of air; at least one outlet 206 for expelling air; a pump 212 configured to induce airflow from the at least one inlet 204 to the at least one outlet 206; and a sterilisation unit 210 configured to sterilise air, wherein the sterilisation unit 210 is downstream of the at least one inlet 204 and upstream of the at least one outlet 206. The at least one inlet 204 is configured to be positioned at a first height level within an occupiable space 202, and the at least one outlet 206 is configured to be positioned at a second height level within the occupiable space 202 below the first height level. The sterilisation unit 210 may include an ultraviolet C (UVC) light source and a helical vane for guiding air within the sterilisation unit 210 around a helical path. There is also a method of installing the air sterilisation system 200.

Description

AIR STERILISATION SYSTEM FOR ROOM OR ZONE

Technical Field

This invention relates to air sterilisation, and in particular a system and method for sterilising an occupiable space.

Background of the Invention

Conventionally, devices and systems for air ventilation and air sterilisation create a homogenous air mixture by forcing air into an area. These systems have an exhaust output that acts as a source of filtered and/or sterilised air. Air is forced from the exhaust output in a turbulent manner into the surrounding area where it mixes with the air that is already present.

Systems such as these include Heating, Ventilation and Air Conditioning (HVAC) units, which produce a large airflow with a high mixing rate between air forced from an exhaust output and air already present in the area in which the HVAC unit is located.

Similarly, Mechanical Ventilation with Heat Recovery (MVHR) systems provide fresh filtered air into an area such as a building whilst retaining most of the energy that has already been used in heating the building. In HVAC and MVHR systems, the exhaust output is usually ceiling mounted. These systems may also include an inlet that pulls air out of the area or building. The inlet is also usually ceiling mounted. The exhaust output and the inlet may also be in different rooms. Air is ejected from the exhaust output in a turbulent manner to encourage mixing with the air present in the area or building.

Other air ventilation systems or devices include fans. Fans may include a heating or cooling element, and work by mechanically pulling air from one direction and pushing it in an opposite direction in a turbulent manner. In some devices, fans are incorporated into standalone sterilisation units. A sterilisation unit such as this pulls in air from its immediate surroundings and directs, by a fan or otherwise, filtered and/or sterilised air outwards in a turbulent manner, where it mixes with the rest of the air present in an area.

Furthermore, some devices use uncontained Ultraviolet C (UV-C) light to sterilise air and surfaces. These devices include a source of UV-C light, such as a UV-C lamp, and are effective at killing pathogens and disinfecting areas. However, UV-C light is harmful to humans. For example, it can damage the cornea if observed directly, and can have mutagenic and/or carcinogenic effects. Therefore, an area such as a room undergoing treatment with UV-C light cannot be occupied until after treatment is ceased.

In some implementations, UV-C lamps are positioned at a high level and face upward towards the ceiling. In taller occupied rooms, this allows air that passes over the UV-C lamp to be sterilised, whilst the risks associated with UV-C light are reduced, since the light is directed away from the ground-level area of the occupied room. Air is sterilised by the lamps as it passes over the lamps naturally. This implementation thus relies on the natural airflow within a room, for example airflow caused by convection.

A problem with each of these devices and systems is that they allow or encourage ventilated or sterilised air to mix with air that has not been treated by the device or system.

Where the devices and systems use an active exhaust output such as a fan, the airflow created is turbulent. These two aspects create a homogenous air mixture that reduces the overall air quality and limits the effectiveness of the devices and systems, since the air mixture includes potentially contaminated or dirty air as well as the sterilised or ventilated air.

As such, an occupant of a building is still at a high risk of breathing in contaminated or dirty air when they breathe in air from the homogenous air mixture.

It has been appreciated that it would be desirable to solve this problem by providing a system and a method of installation of the system that takes into consideration the air that has not been ventilated and sterilised, and reduces the mixing of this air with the air that has been ventilated and/or sterilised, with the benefit of providing an occupant or occupants with cleaner air to breathe.

Summary of the Invention

According to a first aspect of the invention, an air sterilisation system is provided, the system comprising: at least one inlet for allowing ingress of air; at least one outlet for expelling air; wherein the at least one inlet and the at least one outlet are connected to form a ventilation passageway; a pump configured to induce airflow within the ventilation passageway from the at least one inlet to the at least one outlet; a sterilisation unit configured to sterilise air, wherein the sterilisation unit is downstream of the at least one inlet and upstream of the at least one outlet, such that the at least one inlet, the sterilisation unit, the pump and the at least one outlet are in fluid communication; and wherein the at least one inlet is configured to be positioned at a first height level within an occupiable space, and the at least one outlet is configured to be positioned at a second height level within the occupiable space, wherein the second height level is below the first height level, such that when in use, air within the occupiable space follows a flow path from the at least one outlet at the second height level to the at least one inlet at the first height level.

Sterilised air that is expelled or exhaust from the ventilation passageway through the at least one outlet is done so at a lower height level than the position of the at least one inlet. This provides a flow path of air in the occupiable space from low-height to high-height, which has advantageous effects for ventilation of the occupiable space. Firstly, the flow path created by the sterilisation system may aid pre-existing or natural convection currents within the occupiable space, which improves the circulation of air and in particular the sterilised air expelled from the at least one outlet. Generally, air that interacts with an occupant, either through breathing, motion or contact, heats up as it does so. Thus, potentially contaminated air is more likely to rise in a convection current, away from the sterilised air being expelled from the at least one outlet at the second height level. This reduces the chances of contaminated air mixing with sterilised air. Secondly, the airflow induced by the pump and the consequent flow path in the occupiable space reduces mixing of sterilised and non-sterilised air, since air is kept moving in a general upwards direction within the occupiable space. Whilst sterilised air is introduced into the occupiable space at the second height level, non-sterilised or contaminated air, such as are breathed out by an occupant in the occupiable space, flows to the at least one inlet at the first height level where it is taken out of the occupiable space for sterilisation by the sterilisation unit. The invention thus takes advantage of natural convection currents as well as the airflow induced by the system in order to maintain a low to high flow path within the occupiable space. This may increase the relative amount of sterilised air being breathed in by occupants of the space, and may decrease the time required, from start-up of the system, to provide the occupants with sterilised air because the entire space does not require sterilisation because of the reduced mixing of sterilised and non-sterilised air. In an occupiable space without a heat or cold source, or with a limited heat differential between the occupiable space and the heat or cold source, air in the occupiable space may stratify into loose thermal layers. The air sterilisation system in effect takes the highest upper band of these thermal layers, sterilises it and passes it back to a lower point in the occupiable space.

The sterilisation unit is provided downstream of the at least one inlet, meaning that it is between the at least one inlet and at least one outlet, such that air that enters the at least one inlet passes through the sterilisation unit to be sterilised.

The pump is provided downstream of the at least one inlet, meaning that it is between the at least one inlet and the at least one outlet, and may be downstream or upstream of the sterilisation unit. In other words, the ordering of components from the at least one inlet to the at least one outlet may be the pump and then the sterilisation unit or the sterilisation unit and then the pump.

The occupiable space is any area capable of being occupied, preferably by a human, but optionally by any other animal. The occupiable space may be a room, such as an office, a restaurant, a kitchen, a hospital ward, a cinema, an operating theatre, or a laboratory, for example. Further examples of an occupiable space include a corridor, a waiting area, a stairwell an escalator and a reception area, such as those in schools, hospitals, train stations and underground stations. Alternatively the occupiable space may be an area within a vehicle, such as a boat deck, a plane cabin, a cockpit, or the interior of a road vehicle.

Activation of the pump induces an airflow within the ventilation passageway from the at least one inlet to the at least one outlet, where air is then expelled into the occupiable space. As a consequence of the airflow between the pump and the at least one outlet, an area of higher than ambient air pressure is created downstream of the pump, between the pump and the at least one outlet. This pushes the air in the ventilation passageway out of the outlet. Simultaneously, when the pump is activated, a relatively lower than ambient air pressure is created in the first passageway portion behind the pump, between the at least one inlet and the pump. This helps to draw in air from the occupiable space through the at least one inlet and towards the pump. In other words, activation of the pump creates a positive air pressure differential towards the at least one outlet and a negative air pressure differential towards the at least one inlet of the ventilation passageway, when compared to the ambient air pressure of the occupiable space. These positive and negative pressure differentials facilitate the airflow along the flow path within the occupiable space from the at least one outlet at the second height level to the at least one inlet at the first height level. As such, activation of the pump advantageously causes the flow of sterilised air to the occupiable space and non-sterilised air from the occupiable space to the sterilisation unit in the ventilation passageway, through the at least one inlet.

The pump may be a fan or the like. The pump may be positioned at any position at or between the at least one inlet and the at least one outlet within the ventilation passageway. There may be multiple pumps within the ventilation passageway. This helps to maintain the consistency of the flow rate within the ventilation passageway.

Preferably, the flow path from the second height level to the first height level is in the same direction as a convection flow within the occupiable space. As explained above, sterilised air is introduced to the occupiable space at the second height level by the at least one outlet. At the same time, air is collected and removed from the occupiable space by the at least one inlet at the first height level. Since the first height level is above the second height level, the natural convection flow of air in the occupiable room is aided by the flow of air into the at least one inlet and out of the at least one outlet. This is advantageous because air in the occupiable space follows an airflow path that is in an upwards direction.

Once air reaches the first height level it is likely to enter the ventilation passageway via the at least one inlet, and as such, contaminated or otherwise unsterile air is less likely to mix with the sterilised air expelled from the at least one outlet.

Preferably, the ventilation passageway includes means for reducing turbulence between the pump and the at least one outlet. Means for reducing turbulence may also be included in any part of the ventilation passageway, between the at least one inlet and the sterilisation unit, and between the sterilisation unit and the pump, for example. The means for reducing turbulence may include airflow vanes, air straighteners, flow isolators and dimensional changes within the ventilation passageway, such as diverging or tapered walls, for example. It is preferable that these features for reducing turbulence are positioned at least in places where the ventilation passageway changes direction, such as at corners in ventilation connectors or ducting. An advantage of including these features is that the turbulence of air expelled by the at least one outlet can be reduced, which means it is less likely to mix with potentially contaminated air already present in the occupiable space. Maintaining laminar flow at the at least one outlet optimises separation between the sterilised air and non-sterilised air. Furthermore, reducing the turbulence ensures a more uniform flow path in the occupiable space from the at least one outlet to the at least one inlet, and reduces the likelihood that air remains within the occupiable space for a long period of time without being sterilised by the system. As such, preferably, the system is configured such that the Reynold's number of air expelled at the at least one outlet does not exceed 2900. More preferably still, the system is configured such that the Reynolds number of air expelled at the at least one outlet does not exceed 2300. This means that the flow of air expelled out of the at least one outlet is substantially laminar.

Preferably, the system is configured to be fitted within the occupiable space. The ventilation passageway may be fitted along a wall of the occupiable space, for example. The system may be a standalone unit that can be retrofitted to an existing occupiable space without the need to modify the infrastructure of the occupiable space. The ventilation passageway is impermeable to air from the occupiable space except from at the at least one inlet and at least one outlet, which are in fluid communication with the occupiable space. This ensures that sterilised air is not mixed with non-sterilised air within the ventilation passageway.

Alternatively, at least a part of the ventilation passageway defined by the at least one inlet, the at least one outlet, the sterilisation unit, and the pump is located externally to the occupiable space. The at least one inlet and the at least one outlet may form part of a wall, ceiling or floor that define the boundaries of the occupiable space, or may be fixed or connected by ventilation connectors to specific points within the occupiable space. The at least one inlet and the at least one outlet provide fluid communication between the remaining components of the ventilation passageway, such as the sterilisation unit and the pump, and the occupiable space. All or some of the ventilation passageway may thus be outside the walls, ceiling or floor or otherwise the boundaries of the occupiable space.

Preferably, the air sterilisation system includes a plurality of outlets, each of the plurality of outlets configured to be positioned at or below the second height level. The plurality of outlets may all be at the same height level or may be distributed at varying height levels equal to or below the second height level. The plurality of outlets are each connected to the ventilation passageway and expel air sterilised by the sterilisation unit to the occupiable space. Having a plurality of outlets is advantageous as it allows for a more uniform flow path across the entire occupiable space when compared to an individual outlet. A plurality of outlets also allow for more air to be expelled in a non-turbulent manner. Preferably, the air sterilisation system further comprises a manifold configured to couple each of the plurality of outlets to the ventilation passageway. This allows for one pump and one sterilisation unit to be used to expel sterilised air from all of the plurality of outlets. The manifold connects upstream of the plurality of outlets to the ventilation passageway where the pump and the sterilisation unit are located. A benefit of this is that only one sterilisation unit is required to sterilise the air for all outlets. Alternatively, there may a plurality of pumps and/or a plurality of sterilisation units, whereby one or more sterilisation units and pumps may be responsible for sterilising and expelling air from multiple outlets. Each outlet may have its own additional pump for exhausting sterilised air into the occupiable space.

Preferably, the air sterilisation system comprises a plurality of inlets, each of the plurality of inlets configured to be positioned at or higher than the first height level. The plurality of inlets may all be at the same height level or may be at varying height levels equal to or above the first height level. The plurality of inlets are each connected to the ventilation passageway by ventilation connectors and allow ingress of air from the occupiable space into the ventilation passageway to be sterilised by the sterilisation unit. Having a plurality of inlets is advantageous as it allows for a more uniform flow path across the entire occupiable space when compared to an individual inlet.

Preferably, the air sterilisation system further comprises a manifold configured to couple each of the plurality of inlets to the ventilation passageway. This allows the air collected by each of the plurality of inlets to be sterilised by a single sterilisation unit.

Preferably, the sterilisation unit includes an ultraviolet C (UV-C) light source. A UV-C light source is effective at killing harmful pathogens in the air. The sterilisation unit may alternatively or further include a mercury discharge bulb, one or more UV-C light-emitting diodes (LED) type sources, or other such UV-C light emitters.

Preferably, the air sterilisation system further comprises an air filter downstream of the at least one inlet and upstream of the at least one outlet. A filter is advantageous because it cleans air by removing particulates such as pollution, pollen and dust. Preferably the air filter is upstream of the sterilisation unit to remove dust particles in the airflow upstream of the sterilisation unit. Dust particles can absorb UV-C light, so by removing them prior to the sterilisation unit, the sterilisation unit functions more effectively at sterilising the airflow within the air sterilisation system. The filter may be a High-efficiency particulate air (H EPA) filter, an Ultra-low particulate air (ULPA) filter or the like.

Preferably, the at least one inlet comprises: a surface wall that surrounds and defines an interior space of the inlet; one or more air-permeable holes through the surface wall configured to allow ingress of air from the occupiable space into the interior space of the inlet; and a primary connection point configured to couple to the ventilation passageway, such that the interior space of the inlet is in fluid communication with the ventilation passageway. The inlet may include grooves within the interior space of the inlet, configured to direct airflow from the one or more air-permeable holes to the primary connection point. The inlet may be any shape, but is preferably a cylinder or an ellipsoid, comprising a plurality of air-permeable holes spaced evenly and regularly around its surface wall. This encourages laminar flow into the inlet from substantially every direction around the inlet.

The holes that perforate the surface wall of the inlet may be circular, elongate slits, or the like.

The system may comprise one or more primary-type inlets. The primary-type inlet differs from the inlet described above in that the primary-type inlet comprises a secondary connection point and internal ventilation connectors. The primary-type inlet is configured to connect directly to the ventilation passageway via the primary connection point of the primary-type inlet, and is configured to connect to a further inlet as described above via the secondary connection point. A ventilation connector is connected between the secondary connection point of the primary-type inlet and the primary connection point of the further inlet. The internal ventilation connector connects between the primary connection point and the secondary connection point within the interior space of the primary-type inlet, such that the further inlet is in fluid communication with the ventilation passageway via a path along the ventilation connector between the primary connection point of the further inlet and the secondary connection point of the primary-type inlet, and then along the internal ventilation connector between the secondary connection point and the primary connection point of the primary-type inlet. This means that the internal ventilation connector bypasses the interior space of the primary-type inlet such that the further inlet is in fluid communication with the ventilation passageway without being in fluid communication with the internal space of the primary-type inlet. This allows a negative pressure differential within the ventilation passageway to be maintained in both the primary-type inlet, to which the ventilation passageway is directly joined, and the further inlet, to which the ventilation passageway is indirectly joined.

Optionally, the primary-type inlet comprises a plurality of secondary connection points, each for connecting to a further inlet. The primary connection point of the primary-type inlet is configured to provide a plurality of ports for connecting to internal ventilation connectors and for allowing fluid communication with the ventilation passageway. Each of these ports are sealed from each other, to ensure that the internal ventilation connectors that connect to the ports are not in fluid communication with each other, such that a negative pressure differential can be maintained in each internal ventilation connector and each further inlet.

Preferably, the at least one outlet is configured to expel air in a substantially horizontal direction at the second height level, to improve the laminar flow of the exhausted sterilised air and to reduce mixing with unsterilised air in the occupiable space.

Alternatively, the at least one outlet is configured to expel air in an upwards direction, towards the first height level. This means that the at least one outlet is arranged such that airflow induced by the pump is configured to leave the ventilation passageway through the outlet in a generally upwards direction, towards the first height level and the at least one inlet. Arranging the at least one outlet in this way aids the flow path within the occupiable space from the second height level to the first height level.

The at least one outlet may be formed of a hole, slit or the like within a ventilation connector of the ventilation passageway, downstream of the pump and the sterilisation unit.

The first height level may be below a maximal height level of the occupiable space, such that the at least one inlet is spaced from the maximal height level, e.g. the ceiling, of the occupiable space. In this instance, the air sterilisation system may further comprise: at least one secondary sterilisation unit, the at least one secondary sterilisation unit being positioned at a height level between the at least one inlet at the first height level and the maximal height level of the occupiable space, wherein the at least one secondary sterilisation unit is configured to directly sterilise air within the occupiable space between the first height level and the maximal height level. The secondary sterilisation unit may be a UV-C lamp or the like. The at least one inlet and its support or connecting structure, such as ducting, that connects the at least one inlet to the ventilation passageway, is configured to be opaque to UV-C light, such that the at least one inlet and/or its supporting or connecting structure blocks light at the first height level from the secondary sterilisation unit above, shielding occupants within the occupiable space from the UV-C light.

Preferably, the occupiable space is one of: a building, a room, and an interior space of a land, sea, or air vehicle. As discussed above, the occupiable space is a defined area that is capable of being occupied, and is bordered by fixed boundaries such as walls, windows, ceilings and floors. The sterilisation system according to the first aspect of the invention sterilises air and circulates it according to the flow path within the occupiable space.

According to a second aspect of the invention, an inlet for allowing ingress of air to a ventilation system is provided. The inlet comprises: a surface wall that surrounds and defines an interior space of the inlet; one or more air-permeable holes through the surface wall configured to allow ingress of air from an occupiable space into the interior space of the inlet; and a primary connection point configured to couple to a ventilation passageway, such that the interior space of the inlet is in fluid communication with the ventilation passageway. The inlet may include grooves within the interior space of the inlet, configured to direct airflow from the one or more air-permeable holes to the primary connection point. The inlet may be any shape, but is preferably a cylinder or an ellipsoid, comprising a plurality of air-permeable holes spaced evenly and regularly around its surface wall. This encourages laminar flow into the inlet from substantially every direction around the inlet. The holes that perforate the surface wall of the inlet may be circular, elongate slits, or the like.

As will be appreciated, the features described above in relation to the air inlet of the air sterilisation system may be provided in any appropriate combination with the inlet of the second aspect of the invention.

According to a third aspect of the invention, a method of installing the air sterilisation system is provided, the method comprising: determining a height of work and/or occupancy for the occupiable space; fixing the at least one outlet substantially at the height of work and/or occupancy, such that the second height level is substantially the height of work and/or occupancy; fixing the at least one inlet at the first height level in the occupiable space; Height of work means the general height level at which an occupant of the occupiable space is most likely to perform work or other tasks, given the purpose of the occupiable space. On a factory floor, this may be approximately at waist height or the height of workbenches and machines, for example. In an office, this may be at the height or just below the height of a desk, for example. In a hospital, this may be at the height of a hospital bed, for example. The height of occupancy is the height at which the occupant of the occupiable space is most likely to occupy, given the purpose of the occupiable space. In a commercial airplane cabin or bus, the height of occupancy may be seat-level. Similarly in a restaurant, the occupancy height may be a sitting height, or at or just below a height of a dining table. It is to be understood that where there are a plurality of inlets and outlets, each outlet may be located at a height corresponding to the height of occupancy or a particular feature within the occupiable space. For example, a restaurant may have an outlet just below or fixed to each dining table. The height of each outlet is thus dependent on the height and relative height of each dining table. The plurality of inlets may also be at a fixed height above the height of occupancy such that the positions of the inlets are also dependent on where the occupants are likely to be within the occupiable space. For example, in a restaurant, an inlet may be positioned directly above each dining table. In a bus for example, the inlets and outlets may be higher or lower at positions where occupants are intended to stand compared to inlets and outlets where seats are provided. This provides a bespoke solution to a range of different occupiable spaces that ensures that the places where an occupant is likely to occupy and/or work are subject to the airflow and benefits provided by the invention.

Brief Description of the Drawings

The invention will now be further described, by way of example only, with reference to the drawings in which: Figure 1 is schematic diagram of a sterilisation system according to the invention; Figure 2 is a perspective diagram of an alternative sterilisation system; Figure 3 is a perspective diagram of a further alternative sterilisation system; Figures 4A and 4B are schematic diagrams of an inlet according to the invention; Figure 5 is a schematic diagram of a primary-type inlet according to the invention; Figures 6A to 6E are diagrams showing variations of ventilation connectors according to the invention; Figure 7 is cross sectional diagram of an aircraft cabin including a sterilisation system according to the invention; and Figure 8 is a perspective diagram of a restaurant or bar including a plurality of sterilisation systems according to the invention.

Detailed Description of the Preferred Embodiments

Figure 1 shows a sterilisation system 100 according to the invention. The system includes at least one inlet 102, at least one outlet 104, ventilation connectors 106, a sterilisation unit 108, and a pump 110. The at least one inlet 102 is located at a first height level 112 in an occupiable space 116, and the at least one outlet 104 is located at a second height level 114 in the occupiable space 116. The at least one inlet 102, the sterilisation unit 108, the pump 110 and the at least one outlet 104 are connected by ventilation connectors 106 to form a ventilation passageway. The at least one inlet 102 and the at least one outlet 104 provide fluid communication between the occupiable space 116 and the ventilation passageway. It is to be understood that any reference to 'an outlet' and 'an inlet' from henceforth refers to 'at least one outlet' and 'at least one inlet', unless explicitly stated otherwise.

In operation, air is received by the inlet 102, and travels through the ventilation passageway via the ventilation connectors 106. The air then travels through a sterilisation unit 108, where the air is subject to treatment to remove particulates and/or kill pathogens. The pump 110 is configured to induce an airflow in the ventilation passage way, whereby the airflow moves from the inlet 102 to the outlet 104, in an anti-clockwise motion according to the example shown in Figure 1. Once the air has been treated and sterilised by the sterilisation unit 108, it continues to flow to the outlet 104 via the ventilation connectors 106.

The outlet 104 then allows this air to exit the ventilation passageway into the occupiable space 116. The action of the pump 108 in inducing the airflow causes the air to be expelled from the outlet 104 into the occupiable space 116. This airflow also aids to pull in air at the inlet 102 from the occupiable space 116. In other words, the airflow induced by the pump 108 provides a volume of negative pressure in the ventilation passageway upstream of the pump 108 relative to the ambient pressure of the occupiable space 116, and a volume of positive pressure in the ventilation passageway downstream of the pump 108 relative to the ambient pressure of the occupiable space 116. These pressure differentials allow the system 100 to collect air at the inlet 102 and exhaust air at the outlet 104 more effectively.

As described above, the inlet 102 is positioned at a first height level 112, and the outlet 104 is positioned at a second height level 114 within the occupiable room 116. The first height level 112 is higher than the second height level 114. As such, when air is expelled or exhausted from the outlet 104 at the second height level 114, it travels upwards towards the inlet 102 at the first height level 112, where it may be received by the inlet 102 and fed into the ventilation passageway. This means that the air follows a flow path within the occupiable space 116 in a general upwards direction, from the second height level 114 to the first height level 112. When looking at the airflow within the ventilation passageway, air follows an anti-clockwise path in the example as shown in Figure 1, from the inlet 102, through the ventilation passageway, out of the outlet 104, before travelling through the occupiable space 116 and eventually reaching the inlet 102 again. This cyclical flow of air means that air is sterilised often and continuously, and helps to reduce the presence of stagnant air within the occupiable space 116, and in particular at a working level in the vicinity of the occupants. Furthermore, convection currents within the occupiable space 116 will naturally carry relatively hot air higher. The sterilisation system takes advantage of these convection currents to receive air that has risen to the first height level 112 via the inlet 102. In an occupiable space, interactions between air and an occupant, for example through breathing, contact or motion, can heat up the air, causing it to rise in the convection currents.

Air that has interacted with an occupant in this way is more likely to be contaminated with pathogens. By positioning the inlet 102 at a first height level that is high in the occupiable space 116, it is more likely that this contaminated air is taken out of the occupiable space 116 to be sterilised by the sterilisation system 100.

Figure 2 shows a perspective view of the system 200. In Figure 2, the occupiable space 202 is a room containing occupants, such as an office. Similarly to the system 100 shown in Figure 1, the system 200 comprises an inlet 204, an outlet 206, ventilation connectors 208, a sterilisation unit 210 and a pump 212. As shown in Figure 2, the sterilisation unit 210 and the pump 212 can be housed in the same combined unit in the ventilation passageway. Air is drawn in to the inlet 204 from lateral directions at the first height level, as shown by the arrows in Figure 2. Similarly, air is exhausted from the outlet 206 in lateral directions at the second height level. Figure 2 shows that the system 200 provided as a standalone unit that does not require adaptation or adjustment of the infrastructure, meaning the walls, floors and ceilings, of the occupiable space 202. Figure 3 shows an alternative example of an air sterilisation system 300. In this alternative, the system 300 comprises two inlets 204, connected to the ventilation passageway via ventilation connectors 208. In this example, an alternative, elongate outlet 302 is provided in the form of a ventilation connector with holes, slots or the like perforated into a side surface. This allows the outlet 302 to exhaust air in a uniform lateral direction perpendicular to the direction of the elongate outlet 302.

It is to be understood that any combination of the inlets and outlets as discussed here and as illustrated in the figures may be used in the air sterilisation system. Furthermore, it is noted that the inlet or the outlet may be integrated with the sterilisation unit and the pump in the combined unit. In the system 200 as shown in Figure 2 for example, the inlet 204 may be integrated in the combined unit including the sterilisation unit 210 and the pump 212, at the first height level. The only ventilation connector 208 that is needed in this example is one to connect the combined unit to the outlet 206 at the second height level.

Each of the components of the systems 100, 200, 300 will now be described in more detail, starting with the inlet 102. As will be appreciated, the inlet 204 may take the form of inlet 102 described here. The inlet 102 is a device configured to allow ingress of air into the ventilation passageway. As shown in Figure 4A, the inlet 102 comprises a surface wall 1020 that defines an interior space 1022. The surface wall 1020 is perforated by air-permeable holes 1024, allowing for ingress of air from outside the inlet 102 to the interior space 1022. In Figure 4A the inlet is in the shape of a cylinder, but it is to be understood that any other three-dimensional shape is useable, such as an ellipsoid. The inlet 102 comprises a primary connection point 1026 for connecting to ventilation connectors 106. The connection between the inlet 102 and the ventilation connectors 106 allows the air received by the inlet 102 to flow into the ventilation passageway towards the sterilisation unit 108 through the connectors 106. Arrows 102f illustrate an example of how air flows from the outside of the inlet 102, through the holes 1024 and then through the ventilation connectors 106. The inlet 102 may comprise one or more grooves or airflow vanes to channel air from the holes towards the primary connection point 1026. Figure 4B shows a cross-section plan view of the inlet 102 again illustrating the airflow via arrows 102f. As can be seen from Figure 4B, air flows into the interior space 1022 of the inlet 102, where it then flows via the ventilation connectors 106. There may be multiple ventilation connectors 106 as shown in Figure 4B.

When the inlet forms part of the combined unit containing the sterilisation unit and the pump as discussed above, it connects directly to the combined unit. In this instance the primary connection point 1026 connects directly to or within the combined unit.

As discussed above, there may be more than one inlet 102 in the system 100. In this case, one or more inlets 102 function as primary-type inlets 102a, as shown in Figure 5. The primary-type inlet 102a comprises all of the features of the inlet 102, but further comprises a secondary connection point 1028 and an internal ventilation connector 1030. The secondary connection point 1028 is configured to connect to the internal connector 1030 and a ventilation connector 106 connecting to a further inlet 102. The internal ventilation connector 1030 is configured to connect the secondary connection point 1028 to the primary connection point 1026 in order to allow ingress of air from the further input 102 to the ventilation passageway, via the primary-type inlet 102a. The internal ventilation connector 1026 provides an isolated passageway from the further inlet 102 to the primary connection position 1026, that it is air-impermeable from outside of the internal ventilation connector 1026. The presence of the internal ventilation connector 1026 ensures that connections to further inlets 102 from the primary-type inlet 102a do not disrupt the capability of the primary-type inlet 102a to receive air itself. In particular, arrows 102f in Figure 5 illustrate that both the inlet 102 and the primary-type inlet 102a allow air into their respective interior spaces 1022. When the ventilation passageway experiences a negative pressure relative to the ambient pressure of the occupiable space 116, due to action of the pump 110, the internal ventilation connector 1026 and the secondary connection point 1028 ensure that the negative pressure is distributed to both the primary-type inlet 102a and the further inlet 102, since these features provide a direct connection between the inlet 102 and the ventilation passageway. It is to be understood that the primary-type inlet 102a can comprise multiple secondary connections, each connecting to a further inlet 102. The further inlets 102 may be considered as distributed inlets 102, each connected to the primary-type inlet 102a, which functions as a main inlet. Alternatively, the at least one inlet 102 may only include inlets 102 and not a primary-type inlet 102a.

Next, the outlet 104 is described. The outlet 104 defines the end point of the ventilation passageway, and provides the only point of fluid communication between the ventilation passageway and the occupiable space 116 other than the inlet 102. The outlet allows air to exhaust from the ventilation passageway to the occupiable space 116 at the second height level 114. A purpose of the outlet 104 is to ensure that air is expelled or exhausted in a non-turbulent manner. In this respect, the outlet 104 may include turbulence-reduction features such as vanes and flow straighteners. These features ensure that air exhausted from the outlet 104 is substantially laminar. In order to aid the flow path of air within the occupiable space 116, the outlet may be configured to exhaust air in a vertically upwards direction, from the second height level to the first height level, or at least in a direction that has a vertically upwards component. In Figure 2, the outlet 104 may have the same shape and features as the inlet 102. In order to exhaust sterilised air from the air sterilisation system further within the occupiable space 116, the outlet 104 may comprise one or more horizontal extensions for guiding exhausted air further into the occupiable space before it exits the system. In Figure 3, the outlet 302 is formed of a ventilation connector 106, perforated with holes, slits, or the like, for exhausting sterilised air.

Referring now to Figures 6A to 6E, the ventilation connectors 106 are described.

The ventilation connectors 106 are responsible for connecting each of the inlet 102, the sterilisation unit 108, the pump 110, and the outlet 104 to form the ventilation passageway, and for providing fluid communication between these components. The ventilation connectors 106 have an enclosed inner channel for allowing the passage of air between the connected components. The ventilation connectors 106 may thus be formed of ducting, piping or the like. As will be appreciated, the ventilation connectors described in Figures 6A to 6E may be used in any sterilisation system 100, 200, 300 described herein.

Figure 6A shows a first example of a portion of the ventilation connectors 106. In this first example, the ventilation connectors 106 comprise a plurality of individual connectors 106a. Each of the individual connectors 106a are configured to transport air from one end to the other, as illustrated by the arrows in Figure 6A. Each individual connector 106a may connect to a separate inlet 102 upstream of the individual connectors 106a, or a separate outlet 104 downstream of the individual connectors 106a. The individual connectors 106a may converge into a single connector so that air from each individual connector is provided to the sterilisation unit 108 and the pump 110. Each of the individual connectors 106a may connect to a separate internal ventilation connector 1030 at the primary connection point 1026 of a primary-type inlet 102a, as shown in Figure 5. This ensures that each inlet 102 to which the internal ventilation connectors 1030 connects can receive and collect air without affecting the same capabilities of the primary-type inlet 102a.

Figure 6B shows a second example of a portion of the ventilation connectors 106. In this example, the ventilation connector portion comprises a central individual connector 106a and two adjacent inlet connectors 106b. It is to be understood that there may be more than three such connectors adjacent each other. The inlet connectors 106b are sealed at a first end, denoted by the crosses in Figure 6B. Air is therefore unable to enter the first end.

Along at least one boundary edge of the inlet connectors 106b, a series of air-permeable holes or slits 106b1 are positioned for allowing ingress of air, as illustrated by the arrows in Figure 6B. The inlet connectors 106b thus provide the function of the inlet 102. As such, the system 100 may comprise the inlet connectors 106b instead of the inlet 102, or there may be a combination of these components. In the example shown in Figure 6B, the central individual connector 106a is configured to connect to an inlet 102. Air from the inlet 102 flows through the individual connector 106a as shown by the arrow in Figure 6B. Since the first ends of the inlet connectors 106b are sealed, and the individual connector 106a is not in fluid communication with the inlet connectors 106b, air received at the inlet 102 does not travel through the inlet connectors 106b and negative pressure within the system 100 is maintained in both the inlet connectors 106b and the inlet 102.

Figure 6C shows a third example portion of the ventilation connectors 106. This example includes a single connector 106c, that allows air to flow through it. The single connector 106c is ducting, for example.

Figure 6D shows a fourth example portion of the ventilation connectors 106, comprising the individual connectors 106a, whereby one of the plurality of individual connectors is connected at one end to an internal ventilation connector 1030. This example refers to the configuration as shown in Figure 5, whereby the internal ventilation connector 1030 connects between a primary connection point 1026 and a secondary connection point 1028 within a primary-type inlet 102a or inlet 102. The internal ventilation connector 1030 ensures that negative pressure within the system 100 is maintained at a further inlet 102 connected to the primary-type inlet 102a.

Figure 6E shows a fifth example portion of the ventilation connectors 106, comprising the single connector 106c connected to an internal ventilation connector 1030. This configuration can be used at the primary-type inlet 102a in the same way as the fourth example described above.

It is to be understood that the ventilation passageway can include any one or more of the first to fifth examples described above with reference to Figures 6A to 6E. Furthermore, it is to be understood that the ventilation connectors 106 can be of any three-dimensional shape provided they allow air to flow through a passageway that is isolated from the external surroundings of the connector 106. It is further to be understood that the ventilation connectors 106 may comprise turbulence reduction features and/or airflow guides within their enclosed inner channel. Airflow vanes are provided within the enclosed inner channel, particularly where any changed in direction of the ventilation connectors 106 is required For example, when the ventilation connectors 106 undergo a direction change as shown in Figure 1, where there are direction changes of substantially 90°, the enclosed inner channel comprises airflow vanes and/or flow straighteners to ensure that flow is maintained as laminar as possible. The dimensions of the ventilation connectors 106 may also be modified along the ventilation passageway so that some part of the ventilation passageway are wider or narrower than others. This is useful for accommodating the sterilisation unit 108 and the pump 110, but also for controlling the rate of flow and the turbulence.

The sterilisation unit 108 will now be described. As will be appreciated, the sterilisation unit 108 may be substantially the same as used in any sterilisation system 100, 200, 300 described herein. The sterilisation unit 108 is connected between the inlet 102 and the outlet 104 via the ventilation connectors 106. The sterilisation unit is configured to sterilise the air that passes through a sterilisation area within the ventilation passageway adjacent the sterilisation unit 108. The sterilisation unit 108 includes a sterilising device that provides an output that sterilises the air in the sterilisation area.

In a first example, the device is a UV-C light source, configured to output and direct UV-C light rays at the air in sterilisation area. The ventilation connectors 106 that form the sterilisation area are lined with a reflective material such as aluminium, to allow the UV-C light rays to reflect within the sterilisation area. In this first example, the sterilisation area may be a downward duct, which is relatively larger in cross-sectional area than the ventilation connectors 106, as shown in Figures 2 and 3, whereby the size difference is configured to reduce the air speed within the sterilisation area, while maintaining the airflow rate, to ensure air stays in the sterilisation area for longer.

In a second example, the sterilising device is a UV-C light source such as a UV-C LED. This UV-C light source may be positioned centrally within the sterilisation area defined by the ventilation connectors 106. Helical vanes are provided around the UV-C light source, the helical vanes being configured to guide airflow within the sterilisation area of the ventilation passageway around the UV-C light source, where the air is sterilised. The helical vanes may be formed in two parts configured to join together to allow access for maintenance and bulb-changes. The helical vanes are made of a reflective material such as aluminium.

In a third example, the system 100, 200 or 300 comprises multiple sterilisation units 108 such as UV-C light sources. The multiple UV-C light sources are spaced at intervals along the ventilation passageway. The multiple UV-C light sources emit UV-C light within the ventilation passageway, meaning within the ventilation connectors 106, to sterilise the air therein. The ventilation passageway comprises one or more elongate helical structures within the ventilation passageway, for guiding the air along a helical path within the ventilation passageway. This ensures air is pushed near the UV-C light sources and slows the overall air speed through the ventilation passageway. These two effects ensure that air is sterilised by the UV-C light sources.

In a fourth example, the sterilisation area has a substantially 'D' shaped cross-section. The UV-C light source is fitted at each or one of the corners of the D' shape sterilisation area.

It is to be understood that any one or more of the features of the first, second and third examples of sterilisation units may be combined and implemented together.

The pump 110 will now be described. As will be appreciated, the pump 110 may be used in any sterilisation system 100, 200, 300 described herein. The pump 110 is configured to induce an airflow in the ventilation passageway from the inlet 102 to the outlet 104. The pump is a fan or the like. The fan may be positioned relatively high in the ventilation passageway, near the inlet 102. This increases the flow rate at the inlet 102, of air coming into the sterilisation system 100. This also allows any turbulence created by the pump 110 to be dissipated downstream of the pump 110 within the ventilation passageway, before the air is exhausted into the occupiable space 116. Alternatively or additionally, a pump 110 such as a centrifugal fan may be provided near or at the outlet 104. This provides the directional change required to exhaust air out of the outlet 104 in a direction from the second height level 114 to the first height level 112.

The sterilisation unit 108 may further include an air filter positioned within the ventilation passage. The filter is positioned in the cross-sectional plane of the ventilation passage and is configured to filter air as it flows through it. Alternatively, the filter is positioned in a filter chamber connected within the ventilation passageway by ventilation connectors 106.

It is to be understood that the components of the air sterilisation system 100 that form the ventilation passage can appear in any order between the inlet 102 and the outlet 104.

As such, the sterilisation unit 108 can be downstream or upstream of the pump 110.

Similarly, the pump 110 can be downstream or upstream of the filter. In Figure 1, the pump 110 is downstream of the sterilisation unit 108. In Figures 2 and 3, the pump 110 and the sterilisation unit 108 are located in the same area.

For example, the ordering of components, from the inlet 102 to the outlet 104, includes the filter, followed by the pump 110, and then the sterilisation unit 108. In this example, the inlet 102 is connected to the filter via the ventilation connectors 106. The ventilation connectors 106 between the inlet 102 and the filter taper out to accommodate a filter chamber, wherein the filter is housed. Further ventilation connectors 106 connect the filter chamber to the pump 110. Downstream of the pump, the ventilation connectors 106 taper to an enlarged size and connect to the sterilisation unit 108. The tapering of the ventilation connectors 106 increases the time that the air is present in the sterilisation area by reducing the air speed. The air that is sterilised is then exhausted out from the outlet 104.

The filter, pump 110 and sterilisation unit 108 may all be located substantially within a first half of the ventilation passageway from outlet 102 to inlet 104, to allow air within the ventilation passageway to dissipate any turbulence before it reaches the outlet 104, such that it can be exhausted in a laminar manner.

A method of installing the system 100 and fitting it to an occupiable space will now be described. The method of fitting the system 100 includes fixing the inlet 102 at the first height level 112 and fixing the outlet 104 at the second height level 114, within an occupiable space 116. The choice of the first height level 112 and the second height level 114 is based on some considerations. The first of these is the height of work and/or occupancy of the occupiable space 116. The height of work is the height level or range of height levels in which an occupant is expected to work or perform any other occupant-related activity, based on the purpose of the occupiable space 116. For example, where the occupiable space 116 to be fitted with the system 100 is a hospital, the height of work may be the height of a patient's bed, the height of an operating table, the height of an MRI or CT scanner, or the height of a seat of a chair in a waiting room, depending on to which room or group of rooms the system 100 is to be fitted within the hospital. Once the height of work is determined, the outlet 104 is fitted substantially at or below the height of work. In the example of the hospital, this means that the outlet 104 may be fitted level with or directly underneath a patient's bed, an operating table, an MRI or CT scanner, or the seated portion of a chair in a waiting room. This ensures that sterilised air that has been sterilised by the system 100 is exhausted directly at the point at which an occupant is likely to be working or performing an activity. The height of occupancy describes the expected height at which an occupant is expected to occupy the occupiable space 116. For example, in a passenger airplane, the height of occupancy may be the height level at which a passenger is expected to be at when they are sitting down. The same considerations described above regarding the height of work also apply to the height of occupancy.

The inlet 102 may also be fixed according to the determined height of work. For example, the inlet 102 may be positioned strategically at or above the height of work, such as above a hospital bed, or above a row of seats in a medical waiting room.

A further consideration is the expected position of work and/or occupancy. This describes the actual location within the occupiable space 116 at which an occupant is expected to occupy. The position of the inlet 102 and the outlet 104 may be fitted according to the height of work and/or occupancy and the position of work and/or occupancy. The position of the inlet 102 can be strategically positioned such that it is directly above an expected position of work or occupancy within the occupiable space 116. For example, the inlet 102 may be positioned above an office desk, a restaurant table, or in a classroom, above the expected position of the teacher. In the example of a classroom, the system may have a higher concentration of inlets 102 positioned between the expected position of the teacher and the expected position of the pupils, to aid in capturing dirty or contaminated air and thus to aid in the prevention of transmission of pathogens between the teacher and the pupils.

The system 100 could be applied and fixed to any occupiable space 116 such as a ship, boat, submarine, plane cabin/cockpit, coach, bus, train, truck, minibus or passenger car. The occupiable space 116 may also be enclosed rooms and zones, including commercial, medical, educational and manufacturing areas and those containing animals or livestock. The occupiable space 116 may also be corridors, cellars, or other zones of buildings.

An example configuration of a system 700 in an airplane cabin is shown in Figure 7. The airplane cabin has an occupiable space 116 above the floor of the cabin 704. The determined height of occupancy 702 is based on the height of seats in the cabin. This height may be determined as being the seated part of the seat, or the headrest part of the seat, for example. The inlets 102 are strategically positioned directly above the seats on either side of the cabin, and the outlets 104 are strategically positioned directly below the height of occupancy 702 on each side of the cabin. This configuration ensures that sir flows from the second height level at the outlets 104 to the first height level at the inlets 102, as illustrated by the arrows in Figure 7, which aids the natural convection flow within the cabin.

A further example configuration of system 800 in a restaurant is shown in Figure 8.

This system 800 is different from the system 100 shown in Figure 1 in that the ventilation passageways are positioned outside the boundaries of the occupiable space 116. Ventilation connectors 106 connect the inlets and primary-type inlets 102a to the ventilation passageway where the sterilisation unit 108 and the pump 110 are located. As can be seen form Figure 8, there are two separate systems 800 and 800a. The system 800 is located in a restaurant area of the occupiable space 116 and the system 800a is located in a bar/kitchen area of the occupiable space 116. The system 800 comprises primary-type inlets 102a as well as inlets 102. Each of these inlets 102 and primary-type inlets 102a are positioned at a first height level above restaurant tables. Furthermore, each inlet 102 and primary-type inlet 102a is strategically positioned above a dining table, which is designated as the expected position of occupancy/work. This ensures that dirty or contaminated air, such as air breathed out by occupants, is collected quickly and efficiently.

In use, and as shown in Figures 2, 3, and 8, the circle denotes a person infected with a pathogen having an airborne transmission mode. The sterilisation system of the present invention may act to reduce the probability of that person transmitting the pathogen to others in the occupiable space.

Other examples where specific configurations can provide benefit include gyms, where inlets 102 may be positioned directly above exercise machines with outlets 104 directly below, and children's nurseries, where the height of occupancy is very low, such that the outlets 104 are positioned at ground level.

It is to be understood that any of the above examples relating to features of the system 100 or the method of installing the system may be combined in any combination.

Claims

CLAIMS1 An air sterilisation system comprising: at least one inlet for allowing ingress of air; at least one outlet for expelling air; wherein the at least one inlet and the at least one outlet are connected to form a ventilation passageway; a pump configured to induce airflow within the ventilation passageway from the at least one inlet to the at least one outlet; a sterilisation unit configured to sterilise air, wherein the sterilisation unit is downstream of the at least one inlet and upstream of the at least one outlet, such that the at least one inlet, the sterilisation unit, the pump and the at least one outlet are in fluid communication; and wherein the at least one inlet is configured to be positioned at a first height level within an occupiable space, and the at least one outlet is configured to be positioned at a second height level within the occupiable space, wherein the second height level is below the first height level, such that when in use, air within the occupiable space follows a flow path from the at least one outlet at the second height level to the at least one inlet at the first height level.
2 The air sterilisation system of any preceding claim, wherein the ventilation passageway comprises means for reducing turbulence between the pump and the at least one outlet.
3 The air sterilisation system of any preceding claim, wherein the sterilisation unit comprises a helical vane, wherein the helical vane is configured to guide air within the sterilisation unit around a helical path.
4 The air sterilisation system of any preceding claim, wherein the system is configured such that the Reynolds number of air expelled from the at least one outlet does not exceed 2900.
The air sterilisation system of any of claims 1 to 3 wherein the system is configured such that the Reynolds number of air expelled from the at least one outlet does not exceed 2300.
6 The air sterilisation system of any preceding claim, comprising a plurality of outlets, each of the plurality of outlets configured to be positioned at or below the second height level.
7. The air sterilisation system of claim 6, further comprising a manifold configured to couple each of the plurality of outlets to the ventilation passageway.
8 The air sterilisation system of any preceding claim, comprising a plurality of inlets, each of the plurality of inlets configured to be positioned at or higher than the first height level.
9. The air sterilisation system of claim 8, further comprising a manifold configured to couple each of the plurality of inlets to the ventilation passageway.
10. The air sterilisation system of any preceding claim wherein the sterilisation unit includes an ultraviolet C light source.
11. The air sterilisation system of any preceding claim, further comprising an air filter downstream of the at least one inlet and upstream of the at least one outlet.
12 The air sterilisation system of any preceding claim, wherein one of the at least one inlet is a primary-type inlet, the primary-type inlet comprising: a surface wall that surrounds and defines an interior space of the primary-type inlet; one or more air-permeable holes through the surface wall configured to allow ingress of air from the occupiable space into the interior space of the primary-type inlet; and a primary connection point configured to couple to the ventilation passageway, such that the interior space of the primary-type inlet is in fluid communication with the ventilation passageway.
13. The air sterilisation system of any preceding claim, wherein the at least one outlet is configured to expel air in an upwards direction, towards the first height level.
14. The air sterilisation system of any preceding claim wherein the first height level is below a maximal height level of the occupiable space, such that and there is a space between the at least one inlet and the maximal height level of the occupiable space, wherein the air sterilisation system further comprises: at least one secondary sterilisation unit, the at least one secondary sterilisation unit positioned in the space between the at least one inlet and the maximal height level of the occupiable space, wherein the at least one secondary sterilisation unit is configured to directly sterilise air within the occupiable space.
15. The air sterilisation system of any preceding claim, wherein the occupiable space is one of: a building, a room, and an interior space of a land, sea, or air vehicle.
16. A method of installing the air sterilisation system of any preceding claim, the method comprising: determining a height of work and/or occupancy for the occupiable space fixing the at least one outlet substantially at the height of work and/or occupancy, such that the second height level is substantially the height of work and/or occupancy; fixing the at least one inlet at the first height level in the occupiable space; and connecting the at least one inlet to the at least one outlet externally from the occupiable space to form the ventilation passageway.