GB2601912A

GB2601912A - Gas sterilisation apparatus

Info

Publication number: GB2601912A
Application number: GB2117831.4A
Authority: GB
Inventors: Whelan Euan; Osborne Alan
Original assignee: Cpa Engineered Solutions Ltd
Current assignee: Cpa Engineered Solutions Ltd
Priority date: 2020-12-10
Filing date: 2021-12-09
Publication date: 2022-06-15
Also published as: GB202019508D0; GB202117831D0

Abstract

A gas sterilising apparatus 1 comprising a housing 11 with an inlet 3 and an outlet 7 linked by a conduit 13, a flow device 19 for circulating gas through the conduit, and a germicidal radiation source 15 between the inlet and outlet to sterilise the gas in the housing. The flow device may be a fan, may be inside or outside the housing, and may be coupled to either the inlet or outlet. The radiation source may be a UV source and may be a mercury lamp. The radiation source may comprise multiple sources inside the conduit and may be positioned centrally or radially. The apparatus may comprise a radiation source near the inlet and another source near the outlet, with the flow device between. The conduit may be internal to the housing and the inner surface may be radiation reflecting or absorbing. The internal wall may comprise both reflecting and absorbing areas. The absorbing areas may be positioned near the outlet. The inlet and outlet may have a UV barrier, which may be a grille 5, 9 or an extension of the conduit (figure 6). The apparatus may comprise an ambient recirculation device for use in a building.

Description

Gas Sterilisation Apparatus

Introduction

The present invention relates to a gas sterilisation apparatus and in particular an apparatus for sterilising and re-circulating ambient air indoors.

Background

Buildings with indoor public and private spaces such as shopping centres, offices, hospitals, concert venues, sports centres and arenas all have a ventilation and air conditioning requirement which may include, heating, cooling, changing and recirculating the air in the building.

In 2020, Coronavirus disease 2019 (COVID-19) became a major threat to public health. Covid-19 is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-COV-2). A new infection occurs when an infected person exhales virus-containing respiratory droplets or aerosols which get into the mouth, nose, or eyes of other people who are in close contact with the infected person. It is well known that transmission of the COVID-19 virus is greatly increased indoors.

Respiratory transmission is the spread of the virus through respiratory droplets produced when an infected person breathes, coughs, sneezes or talks. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Spread is more likely when people are in close contact within about 6 feet (1.8 m). Airborne transmission of COVID-19 has also been shown to occur through aerosols containing residual pads of droplets, that are able to stay suspended in the air for longer periods of time.

Both respiratory and aerosol transmission of the virus are much more likely to occur indoor locations such as those mentioned above and for example, restaurants, choir practices, fitness classes, nightclubs, and religious venues. Transmission also occurs in healthcare settings, often when aerosol-generating medical procedures are performed on COVID-19 patients. Long distance dispersal of virus particles has been detected in ventilation systems of a hospital, indicating the possibility of long-range aerosol transmission. Other pathogens such as viruses, moulds and bacteria may be present in both recirculated air and fresh external air and may be hazardous to health.

Due to the seriousness of Covid-19 the public health and governmental response to the disease has been based upon either closing or limiting access to indoor locations 10 so as to minimise the spread of the SARS-CoV-2 virus. The economic and social consequences of this action have been severe.

As the response to the Covid-19 pandemic evolves, many including building managers are seeking solutions to keep building occupants safe from airborne person-to-person infection, particularly where this is caused by aerosol dispersion of a pathogen. In addition, the high level of awareness of the existence and effect of airborne pathogens of different types has caused those responsible for safety in other environments to consider how best to minimise their spread. In particular, care is required in settings where pathogens are likely to become airborne such as food manufacture, waste handling other industrial settings and medical facilities as well as the abovementioned public spaces and working spaces.

Summary of the Invention

It is an object of the present invention to provide an apparatus which will actively and thoroughly sterilise the ambient air in an occupied space, reducing the risk of infection from the transfer of air-borne pathogen containing droplets and/or aerosols.

It is another object of the present invention to create a device which can kill the SARS-COV-2 virus along with other viruses, moulds and bacteria within a single pass of air through the device.

In accordance with a first aspect of the invention there is provided a gas sterilisation apparatus which comprises: a housing with an inlet and an outlet which are linked by a conduit; an flow device for extracting gas from the apparatus surroundings into the housing via the inlet and for expelling the gas from the housing via the outlet; a germicidal radiation source positioned between the inlet and the outlet which irradiates the gas in the housing to sterilise the gas.

Preferably, the housing comprises a first germicidal radiation source positioned at or near the inlet, a second germicidal radiation source positioned at or near the outlet wherein the flow device is positioned in the conduit between the first and the second germicidal sources.

Optionally the housing comprises a flow device positioned at or near the inlet and a germicidal radiation source positioned towards the outlet.

Optionally, the housing comprises a germicidal radiation source at or near the inlet and a flow device towards the outlet.

zo Preferably, the housing comprises an internal conduit.

Preferably, at least one internal surface of the conduit is germicidal radiation reflecting.

Preferably, at least one internal surface of the conduit is germicidal radiation absorbing.

Preferably, the absorbing surface has a UV absorbing coating.

Preferably, the inlet further comprises a UV barrier.

Optionally, the UV barrier is a grille.

Optionally the UV barrier is a conduit which extends from the inlet.

Preferably, the outlet further comprises a UV barrier.

Preferably, the outlet further comprises a diffuser.

Optionally, the UV barrier is a grille.

Optionally the UV barrier is a conduit which extends from the outlet.

Preferably, the flow device is a fan.

Optionally, the flow device is situated outside the housing.

Optionally, the flow device is situated outside the housing and is coupled to the inlet.

Optionally, the flow device is situated outside the housing and is coupled to the outlet.

Preferably, the germicidal radiation source comprises a UV source.

Preferably, the UV source is a mercury lamp.

Preferably the UV source has a wavelength within the UVC range.

Preferably, the wavelength is 253 nanometres (nm).

Optionally, the wavelength is 265nm.

Preferably, the germicidal radiation source comprises an array of individual sources positioned inside the conduit.

Preferably, the individual sources positioned inside the conduit on at least one internal surface.

Optionally, the germicidal radiation source is positioned centrally in the conduit.

Optionally, the germicidal radiation source comprises a plurality of sources mounted radially inside the conduit.

Optionally, the germicidal radiation sources are mounted between 0.25 and 0.75 of the distance along a radius of the conduit.

Preferably, the conduit has an internal wall which in part absorbs UV.

Optionally, the conduit has an internal wall which in part reflects UV to increasing its intensity.

Preferably, the wall comprises reflecting areas and absorbing areas Preferably, the absorbing areas are positioned at or near the part of the conduit where air exits the conduit.

Preferably, the gas sterilisation apparatus comprises an ambient air re-circulation device for use in a building to sterilise recirculated air.

Brief Description of the Drawings

The invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a schematic side view of a first embodiment of the present invention; Figure 2 is a schematic side view of a second embodiment of the present invention; Figure 3 is a schematic side view of a third embodiment of the present invention; Figure 4 is a schematic side view of a fourth embodiment of the present invention; Figure 5 is a schematic side view of a fifth embodiment of the present invention; Figure 6 is a schematic side view of a sixth embodiment of the present invention; Figure 7 is a schematic end view which shows a germicidal source mounted in an apparatus in accordance with the present invention; Figure 8 is a schematic end view which shows another germicidal source mounted in an apparatus in accordance with the present invention; Figure 9 is an exploded view of a seventh embodiment of the present invention; Figure 10 is a side view of the embodiment of figure 9; Figure 11 is an end view of the embodiment of figure 9; Figure 12 illustrates the measured levels of UVc radiation at predetermined zo distances from an embodiment of the present invention; Figure 13 is a side view of an eighth embodiment of the present invention in which ducting is attached to direct the air; Figure 14 is a side view of a ninth embodiment of the present invention in which ducting is attached to direct the air; Figure 15 is a cross sectional front view of a tenth embodiment of the present invention; Figure 16 is a cross sectional isometric view of the tenth embodiment of the present invention; and Figure 17 is a front view of the tenth embodiment of the present invention with the grille removed.

Detailed Description of the Drawings

The present invention as described in the following embodiments provides a gas sterilisation apparatus which can treat a sufficiently high volume of air in a single pass therefore achieving extremely high overall effective air recirculation and sterilisation.

The germicidal UVC radiation output of the apparatus of the present invention provides a sufficiently high dose of UVC per unit of air volume to allow air to be recirculated in a manner similar to that when using a standard air recirculation system.

The apparatus of the present invention has been designed to avoid degradation of components inside the apparatus which may be caused by UVC exposure.

In addition, the housing has been designed to prevent leakage of UVC radiation to ensure that building occupants, maintenance engineers and the like, do not suffer direct exposure to UVC light. In particular the intake and exhaust grilles have been redesigned to minimise escape of UVC, ensuring UVC intensity outside the apparatus was below acceptable safe levels.

The apparatus of the present invention also has been designed to ensure that the germicidal radiation source output, airflow volume and speed provide a target single pass kill rate which neutralises pathogens in the air which enters the apparatus and achieve a sufficient airflow to ensure frequent air changes within the internal space.

Figure 1 is a schematic side view of a first embodiment of the present invention. It shows a sterilisation apparatus 1 which comprises an inlet 3 which is covered by an inlet grille 5 at one end of a housing 11. An outlet 7 which is covered by an outlet grille 9 at the other end of the housing. The inlet and outlet are connected by a conduit or chamber 13. The chamber contains two sets of germicidal light sources which comprise four tubular UVC Mercury lamps. The sets of lamps 13, 15 are arranged on either side of an airflow device which is a fan 19. The grilles 5, 9 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 11.

Figure 2 is a schematic side view of a second embodiment of the present invention.

It shows a sterilisation apparatus 21 which comprises an inlet 23 which is covered by an inlet grille 25 at one end of a housing 31. An outlet 27 which is covered by an outlet grille 29 at the other end of the housing 31. The inlet and outlet are connected by a conduit or chamber 33. The chamber 33 contains a set of germicidal light sources which comprise tubular UVC Mercury lamps which are arranged towards the outlet 29 with the fan 37 positioned towards the inlet 23. The grilles 25, 29 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 31.

Figure 3 is a schematic side view of a third embodiment of the present invention. It shows a sterilisation apparatus 41 which comprises an inlet 43 which is covered by an inlet grille 45 at one end of a housing 51. An outlet 47 which is covered by an outlet grille 49 at the other end of the housing 51. The inlet and outlet are connected by a conduit or chamber 53. The chamber 53 contains a set of germicidal light sources which comprise tubular UVC Mercury lamps which are arranged towards the inlet 43 with the fan 57 positioned towards the outlet 43. The grilles 45, 49 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 51.

Figure 4 is a schematic side view of a fourth embodiment of the present invention.

It shows a sterilisation apparatus 61 which comprises an inlet 63 which has an inlet fan 65 positioned outside the housing 71. An outlet 67 which is covered by an outlet grille 69 at the other end of the housing 71. The inlet and outlet are connected by a conduit or chamber 73. The chamber 73 contains a set of germicidal light sources 75 which comprise tubular UVc Mercury lamps which are arranged towards the inlet 63. The grille 69 and fan 65 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 71.

Figure 5 is a schematic side view of a fifth embodiment of the present invention.

It shows a sterilisation apparatus 81 which comprises an inlet 83 which has a grille 85. An outlet 67 which has a fan 89 positioned outside the housing 91. The inlet and outlet are connected by a conduit or chamber 93. The chamber 93 contains a set of germicidal light sources 95 which comprise tubular UVc Mercury lamps. The grille 85 and fan 89 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 71.

Figure 6 is a schematic side view of a sixth embodiment of the present invention. It shows a sterilisation apparatus 101 which comprises an inlet 103 which is covered by an inlet barrier 105 at one end of a housing 11. An outlet 107 which is covered by an outlet barrier 109 at the other end of the housing. The inlet and outlet are connected by a conduit or chamber 113. The chamber contains two sets of germicidal light sources 115 which comprise four tubular UVc Mercury lamps. The sets of lamps 115 are arranged on either side of an airflow device which is a fan 119.

The barrier comprises lengths of conduit which are curved in order to prevent the UVC light from exiting the device.

Figure 7 is a schematic end view which shows a germicidal source mounted in an apparatus in accordance with the present invention. In this embodiment, a germicidal array 121 comprises 4 UVC sources attached to the wall of a cylindrical conduit 123.

In this example, a UV reflective coating 127 is applied to the wall 123 around the positions of the UVC sources to reflect the UVC back towards the air as it passes through the conduit.

Figure 8 is a schematic end view which shows another germicidal source mounted in an apparatus in accordance with the present invention. In this embodiment, a germicidal array 131 comprises a UVC source 135 positioned centrally within the conduit 133. A UV reflective coating 137 is applied to the wall 133 to reflect the UVC back towards the air as it passes through the conduit.

Figures 9, 10 and 11 show an exploded view, a side view and an end view of the seventh embodiment of the present invention.

The figures show a sterilisation apparatus 141 which comprises an inlet 143 which has a collar 144 and is covered by an inlet grille 145 at one end of a housing 151. An outlet 147 which has a collar 148 and is covered by an outlet grille 149 at the other end of the housing 151. The inlet 143 and outlet 147 are connected by a conduit or chamber 153. The chamber 153 contains two sets of germicidal light sources which each comprise four tubular UVc Mercury lamps 155.

The sets of lamps 155 are arranged on either side of an airflow device which is a fan 157 and a fan mounting block 159. The lamps 155 are connected to the inside wall of the chamber by assembly 156 which comprises clips and a power source and are arranged in diametrically opposite pairs so as to provide irradiation throughout the chamber and prevent areas of shadow which could lead to some of the air flowing through the chamber not being exposed to the radiation or not being exposed for a sufficient amount of time to provide a sufficient level of sterilisation. The fan assembly design is of a type which is suitable for propelling large volumes of air quickly and efficiently.

The grilles 145, 149 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 151. In this example, brackets 161 is fitted to the top of the housing 151 beside the power input 163, the brackets 161 to allow the device to be mounted to a ceiling.

Operation of the present invention will now be described with reference to figures 9 to 11. Ambient air is drawn into the sterilisation apparatus 141 vis the inlet 143.

After passing through the inlet, the air is exposed to a first dose of germicidal radiation which is provided by a first set of radiation sources 155 which are arranged in diametrically opposite pairs evenly spaced around the internal surface of the chamber 153. The grille has profiled cross members which are positioned to block the exit of germicidal radiation from the inlet 143 but allow a suitable volume of air to enter the housing 151.

The treated air passes through the centre of the chamber 153 past the fan 157 to a second set of radiation sources 155 which are arranged in diametrically opposite pairs evenly spaced around the internal surface of the chamber 153. The second set provides additional germicidal treatment in order to further sterilise the air. The air then passes out from the housing 151 via the outlet grille 149 which has profiled cross members which are positioned to block the exit of germicidal radiation from the outlet 147.

In the above embodiment, the device is an ambient air re-circulating appliance which is designed to be mounted at height within buildings. Its purpose is to irradiate the air propelled through it with high powered UVC light via eight mercury lamps to neutralise biological material. It has of a body which creates a plenum or chamber with an electrically powered fan situated in the middle, and UVC lamps. The fan propels a constantly flowing, high volume of air through the plenum, pulling air in from the supply side and pushing out the exhaust side. Eight mercury filled lamps, which are necessary to provide adequate UVC dose, surround the plenum providing complete Ultraviolet Germicidal Irradiation (UVGI).

UVC radiation kills or inactivates microorganisms at certain dosages.

When selecting appropriate technology for Ultraviolet Germicidal Irradiation (UVGI), the UVC intensity is a key factor. UVC intensity from mercury lamps is higher than from LED lights at similar sizes. LED sources available which supply comparable UVC output to mercury lamps are more expensive, larger in size, and generate significant amounts of heat from the diodes. The mercury lamp was selected because of its effectiveness for treating high volumes of air. They have very high UVC output, come in various lengths and may be readily configured into larger assemblies by adding different quantities of lamps dependent on output required.

Mercury UVC emits at a wavelength of 253nm which is in the germicidal range Figure 12 shows a device 171 in accordance with the present invention which has an inlet 179 and an outlet 181. Concentric circles are marked on the diagram which denote distance from the centre of the device 171 at 1 metre 173,2 metres 175 and 3 metres 177. Energy values for emitted UVC radiation in pJ/cm2 are shown at different locations around the device. It is apparent that lower values are found beyond the outlet which has an additional barrier formed by lengths of conduit which are curved in order to prevent the UVC light from exiting the device.

Figure 13 is a side view of an eighth embodiment of the present invention in which ducting is attached to direct the air. It shows a sterilisation apparatus 201 which comprises an inlet 203 which is covered by an inlet grille 205 at one end of a housing 211. An outlet 207 which is covered by an outlet grille 209 at the other end of the housing. The inlet and outlet are connected by a conduit or chamber 213. The chamber contains two sets of germicidal light sources which comprise four tubular UVC Mercury lamps. The sets of lamps 213, 215 are arranged on either side of an airflow device which is a fan 219. The grilles 205, 209 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 211. In this example, ducting is affixed to the inlet 221 and the outlet 225 and such that, in use, when mounted, the inlet and outlet point downwards to direct the air flow and further attenuate UV radiation. Diffusers are mounted on conduit inlet 223 and/or outlet 225. The position of the inlet and outlet of the ducting assists with destratification of air in a space.

Figure 14 is a side view of an eighth embodiment of the present invention in which ducting is attached to direct the air. It shows a sterilisation apparatus 231 which comprises an inlet 233 which is covered by an inlet grille 235 at one end of a housing 241. An outlet 237 which is covered by an outlet grille 239 at the other end of the housing. The inlet and outlet are connected by a conduit or chamber 243. The chamber contains two sets of lamps 243, 245 are arranged on either side of an airflow device which is a fan 249. The grilles 235, 239 are designed to allow the through-flow of gas and to reflect germicidal radiation back into the housing 241.

In this example, ducting is affixed to the inlet 251 and the outlet 255 and such that, in use, when mounted, the inlet is pointed of germicidal light sources which comprise four tubular UVC Mercury lamps. The sets upwards and outlet point downwards to direct the air flow and further attenuate UV radiation. Diffusers are mounted on conduit inlet 253 and/or outlet 255. The position of the inlet and outlet of the ducting assists with destratification of air in a space.

Figure 15 is a cross sectional front view 261 of a tenth embodiment of the present invention. It shows the conduit 263 inside a housing 279 with UV source mounting brackets 265 mounted on the wall of the conduit and UV sources 276 mounted upon the bracket 265. The centre point of the conduit and radius 269, 271 are shown. In this example, the mounting brackets are designed to optimise UVC energy field through the conduit 263 such that the sources 267 provide the highest possible dose emitted at 3600 around the conduit. The UV sources are mounted in a spring clip for simple tool-free source changeout during maintenance.

Figure 16 is a cross sectional isometric view of the tenth embodiment of the present invention. In this case, the conduit wall comprises a UV absorbing mesh. IN another embodiment, this perforated mesh made from polished stainless steel or may be chrome plated to be reflective and therefore act as an amplifier for the UV by increasing its intensity in the area where the air flows through the conduit.

Figure 17 is a front view of the tenth embodiment of the present invention with the grille removed which additionally shows the power source 275 and fan 277.

Improvements and modifications may be incorporated herein without deviating from the scope of the invention.

Claims

Claims 1. A gas sterilisation apparatus which comprises: a housing with an inlet and an outlet which are linked by a conduit; a flow device for extracting gas from the apparatus surroundings into the housing via the inlet and for expelling the gas from the housing via the outlet; a germicidal radiation source positioned between the inlet and the outlet which irradiates the gas in the housing to sterilise the gas.
2. The apparatus as claimed in claim 1 wherein, the housing comprises a first germicidal radiation source positioned at or near the inlet, a second germicidal radiation source positioned at or near the outlet wherein the flow device is positioned in the conduit between the first and the second germicidal sources.
3. The apparatus as claimed in claim 1 wherein, the housing comprises a flow device positioned at or near the inlet and a germicidal radiation source positioned towards the outlet.
4. The apparatus as claimed in claim 1 wherein, the housing comprises a germicidal radiation source at or near the inlet and a flow device towards the outlet.
5. The apparatus as claimed in any preceding claim wherein, the housing comprises an internal conduit.
6. The apparatus as claimed in any preceding claim wherein, at least one internal surface of the conduit is germicidal radiation reflecting.
7. The apparatus as claimed in any preceding claim wherein, at least one internal surface of the conduit is germicidal radiation absorbing.
8. The apparatus as claimed in claim 7 wherein, the absorbing surface has a UV absorbing coating.
9. The apparatus as claimed in any preceding claim wherein, the inlet further comprises a UV barrier.
10. The apparatus as claimed in claim 9 wherein, the UV barrier is a grille.
11 The apparatus as claimed in claim 9 wherein the UV barrier is a conduit which extends from the inlet.
12. The apparatus as claimed in claim 9 wherein, the outlet further comprises a UV barrier.
13. The apparatus as claimed in claim 12 wherein, the UV barrier is a grille.
14. The apparatus as claimed in claim 12 wherein the UV barrier is a conduit which extends from the outlet.
15. The apparatus as claimed in any preceding claim wherein, the flow device is a fan.zo
16. The apparatus as claimed in any preceding claim wherein, the flow device is situated outside the housing.
17. The apparatus as claimed in claim 16 wherein, the flow device is situated outside the housing and is coupled to the inlet.
18. The apparatus as claimed in claim 16 wherein, the flow device is situated outside the housing and is coupled to the outlet.
19. The apparatus as claimed in any preceding claim wherein, the germicidal 30 radiation source comprises a UV source.
20. The apparatus as claimed in any preceding claim wherein, the UV source is a mercury lamp
21. The apparatus as claimed in claim 20 wherein, the UV source has a wavelength within the UVC range.
22. The apparatus as claimed in claim 21 wherein, the wavelength is 253 5 nanometres.
23. The apparatus as claimed in claim 21 wherein, the wavelength is 265nm.
24. The apparatus as claimed in any preceding claim wherein, the germicidal radiation source comprises an array of individual sources positioned inside the conduit.
25. The apparatus as claimed in claim 24 wherein, the individual sources positioned inside the conduit on at least one internal surface.
26. The apparatus as claimed in claims 1 to 24 wherein, the germicidal radiation source is positioned centrally in the conduit.
27. The apparatus as claimed in claims 1 to 24 wherein, the germicidal radiation source comprises a plurality of sources mounted radially inside the conduit.
28. The apparatus as claimed in claim 27 wherein, the germicidal radiation sources are mounted between 0.25 and 0.75 of the distance along a radius of the conduit.
29. The apparatus as claimed in any preceding claim wherein, the gas sterilisation apparatus comprises an ambient air re-circulation device for use in a building to sterilise recirculated air.
30. The apparatus as claimed in any preceding claim wherein, the conduit has an internal wall which in part absorbs UV.
31. The apparatus as claimed in any preceding claim wherein, the conduit has an internal wall which in part reflects UV to increasing its intensity.
32. The apparatus as claimed in claim 30 and 31 wherein, the internal wall comprises reflecting areas and absorbing areas.
33. The apparatus as claimed in claim 28 wherein the absorbing areas are positioned at or near the part of the conduit where air exits the conduit.