WO2021198685A1

WO2021198685A1 - Disinfection device

Info

Publication number: WO2021198685A1
Application number: PCT/GB2021/050800
Authority: WO
Inventors: Peter Langley; Simon Ireland
Original assignee: X-19 Biosecurity Ltd
Priority date: 2020-03-31
Filing date: 2021-03-31
Publication date: 2021-10-07

Abstract

A disinfection device is configured to create a virucidal propylene glycol vapour to reduce encapsulated pathogen fomite transmission and also droplet nuclei transmission. The device includes (a) a liquid propylene glycol reservoir; (b) a heater or atomiser configured to heat or transform liquid propylene glycol into a vapour; (c) a power source or connection to an external power source, to power the heater or atomiser; (d) a control system to control the power source and the heater or atomiser. It also includes an authentication mechanism configured to automatically authenticate a source of liquid PG for use in the device.

Description

DISINFECTION DEVICE

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a disinfection device configured to create a virucidal propylene glycol vapour for reducing encapsulated pathogen fomite transmission and also droplet nuclei transmission. It can be used as a virucide against encapsulated pathogens, namely pathogens that include a lipid membrane or shell, such as SARS-CoV-2. Prevention of future pandemics is a critical global priority, but there is only a narrow window for pre-emptive intervention; during that narrow window, a large range of complimentary approaches will need to be used; this invention is one such approach. This invention may also be used in the management and suppression of epidemics and other infectious disease events, such as seasonal flu.

2. Description of the Prior Art

The novel coronavirus SARS-CoV-2 is an encapsulated pathogen, i.e. a pathogen wrapped in a lipid membrane or shell. There are many other pathogens wrapped in lipid membranes; these include coronaviruses, common cold, influenza , H.I.V., as well as the viruses that cause Ebola, hepatitis B and C, herpes, Zika, dengue, and also bacteria that attack the respiratory tract.

Public health authorities have strongly advised three mechanisms for reducing infection; each addresses a different transmission mechanism: social distancing; hand-washing with soap and water; wearing masks. Respiratory droplets, typically 60 -100 pm in size and essentially mucus, and potentially pathogens, fall rapidly to the ground, generally within 2 metres of its source (e.g. an infected person breathing, talking, sneezing or coughing). Social distancing (e.g. keeping 2m away from others) reduces the risk of directly inhaling these respiratory droplets exhaled by an infected person. Physical screens may also reduce the risk of directly inhaling these respiratory droplets. Respiratory droplets, including pathogens, can land on surfaces; the pathogen can remain active for hours or days and so if an uninfected person touches that surface, and then touches their mouth or eyes, then transmission of the pathogen can occur; this is sometimes referred to as fomite transmission. Regular and extensive hand-washing with soap and water is designed to minimise the risk of fomite transmission. Before proceeding further, it is useful to explore the virucidal action of soap. The shell of an encapsulated pathogen is a lipid bilayer held together by hydrophilic bonds; it is essentially a hydrophilic nanostructure, with the hydrophilic ‘heads’ of lipid molecules bonding tightly together to form an outer shell. The tails of the lipid molecules are hydrophobic and form an inner shell. Within this shell is a second layer of lipid molecules, with hydrophobic tails bonding to the hydrophobic tails of the outer layer, and the inner-facing layer then being the hydrophilic heads of the second layer. So the coronavirus has a bi-layer lipid membrane; the order is, progressing from the outside inwards; hydrophilic heads (the outer surface) connected to hydrophobic tails; hydrophobic tails connected to hydrophilic heads; these hydrophilic heads define an inner lipid surface. The inner lipid surface surrounds genetic material; the bi-layer lipid membrane encapsulates and protects this genetic material. Soap is effective in disrupting the lipid membrane; soap molecules have a hydrophobic tail which force their way through the outer hydrophilic lipid shell of the pathogen in order to bond with the internal hydrophobic tails of the lipid membrane, thereby rupturing the lipid membrane and rendering it ineffective as a pathogen. The hydrophilic head of the soap molecule then binds to water used when washing one's hands; the ruptured lipid membranes are hence carried away with the running water. Soap hence has a dual action, first, operating at the nano-scale to disrupt pathogens lipid membrane; secondly, as a surfactant, enabling those ruptured membranes to be readily washed away under running water.

The third transmission mechanism is airborne transmission; it is not impaired through lm - 2m social distancing, physical screens and hand-washing: airborne transmission occurs when very small respiratory droplets, possibly the residue of larger droplets from which most of the water has evaporated, can remain suspended in air for several hours and can hence travel considerable distances on normal air currents. Airborne transmission can be reduced through the use of appropriate face masks, such as N95 respirators.

By combining social distancing, hand-washing with soap and water and suitable face masks, we can address all three transmission routes: droplet transmission; fomite transmission and airborne transmission, respectively. But this is essentially no different from the public health measures taken against Spanish Flu, over 100 years ago, or indeed plague in the Middle Ages.

Furthermore, whilst social distancing, hand-washing with soap and water and suitable face masks each play an important role in reducing infection risk, once the virus has entered the human body and, in the case of the coronavirus, lodged in the upper respiratory tract, it is impossible to use soap to affect the virus. More sophisticated therapies are needed (Remdesivir; Kevzara; polyclonal hyperimmune globulin; antibodies recovered from patients or animals; corticosteroids; recombinant ACE2; APNOl; mRNA-1273; non-replicating viral vector Ad26 and others). But these require complex and time consuming development and clinical studies.

Chemical disinfectant sprays (e.g. hydrogen peroxide sprays) are effective in sanitising environments like hospital wards, ambulances etc, but continuous occupation and use is not possible since these chemical disinfectant sprays cannot be safely inhaled for long periods. High intensity far-UV-C light is also an effective disinfectant: robot air cleaners that both clean air through HEPA filters (sufficient to trap many viruses and bacteria) and also shine far-UV-C light at the air being recycled, and more generally into a room or other space, can play a useful role in environmental infection management: one drawback however is that surfaces that are in shadow are not disinfected; whilst this can be ameliorated with mobile robots, it is not possible to ensure that all surfaces that might be touched (and hence might lead to fomite transmission) are exposed to sufficient far-UV-C light.

There is also a single strand of 'orphan' research, some 80 years old and minimally cited in the preceding 80 years; this appears to be focussed on addressing airborne transmission and not fomite transmission and describes only a laboratory research set-up, as opposed to a commercially practical system. See: 'The bactericidal action of propylene glycol vapor on microorganisms suspended in air. I.' J Exp Med. 1942 Jun 1; 75(6): 593- 610. doi: 10.1084/ieni.75.6.593. Because this is orphan research, largely unknown to scientists currently working in the field of disinfection, or, more generally, the field of limiting the transmission of infectious pathogens, we include it here for completeness; the applicant explicitly reserves its position on whether this research is citable as prior art, in particular in relation to inventive step. Today, the focus on managing the COVID-19 pandemic is based on vaccines, therapeutics, diagnostics, together with the century-old techniques of limiting the transmission of infectious pathogens through lockdowns, social distancing, hand-washing with soap and water, face masks, and disinfectants (applied to surfaces or applied as a mist of large droplets). New techniques, such as far-UV-C light, are emerging, but have drawbacks. It is unlikely that any single technique will prove to be a complete solution to the problem of limiting the transmission of infectious pathogens; instead, a range of complimentary products and techniques is likely to be required. The present invention adds to this repertoire of products and techniques.

SUMMARY OF THE INVENTION

The invention is a disinfection device configured to create a virucidal propylene glycol vapour to reduce encapsulated pathogen fomite transmission and also droplet nuclei transmission; the device including (a) a liquid propylene glycol reservoir; (b) a heater or atomiser configured to heat liquid propylene glycol to form a vapour; (c) a power source or connection to an external power source, to power the heater or atomiser; (d) a control system to control the power source and the heater or atomiser; and (e) an authentication mechanism configured to automatically authenticate a source of liquid PG for use in the device.

The present invention overcomes the long-held view that aerial disinfectants cannot be safely inhaled for long periods of time and hence cannot provide ambient, background virucidal protection that reduces infection risk from both airborne transmission from small droplet nuclei and also fomite transmission.

In potentially high risk environments, such as ambulances carrying infectious or potentially infectious patients, hospital areas where there are infectious or potentially infectious patients, and infection testing centres, the ability to introduce background, imperceptible environmental pathogen control specifically targeted at reducing pathogen transmission via the droplet nuclei and fomite transmission routes, is a potentially valuable contribution to a broader infection management strategy. Saturated PG vapour at very low concentrations appears to be likely to be an effective virucide against SARS-CoV-2 and could play a role in infection management strategies designed to address future epidemics caused by variants of this pathogen, or other entirely different encapsulated pathogens. It can reduce the risk of pathogen transmission in high risk areas, such as ambulances, hospitals, nursing or care homes, and in areas where super spreader events can readily occur, such as nightclubs, pubs and restaurants. For example, a large domestic room or small hospital ward with 2 - 4 beds might be rapidly and cheaply disinfected, without the need to evacuate staff or patients, through vaporising between 1 and 30gm of PG through, for example, a standard humidifier, such as a steam humidifier or plug in vaporiser, as described later in more detail. Patients and staff could also wear personal, battery powered disinfectant devices that gently pass saturated PG vapour around a user's face, possibly under a clear visor. This provides a much smaller volume to be treated with PG vapour, and can readily be turned on and off as required.

Because it is very important that PG (and not some counterfeit liquid, like plain water) is atomised, one implementation envisages that only authentic PG liquid reservoirs or bottles/containers can be used with an atomising device: the device then authenticates the container (using a conventional authentication handshake) before enabling PG liquid to be used from the container.

Another aspect is a disinfection method comprising the steps of:

(i) transferring, from a source, liquid propylene glycol into a reservoir in a device configured to create a virucidal propylene glycol vapour to reduce encapsulated pathogen fomite transmission and also droplet nuclei transmission;

(ii) using an authentication mechanism to authenticate the source, either prior to, during or after step (i);

(iii) activating a heater or atomiser in the device, the heater or atomiser configured to heat or transform liquid propylene glycol into a vapour, if the authentication is passed. BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying Figures show various implementations of the invention.

Figure 1A shows a PG vapour delivery device with a shallow, heated bowl for PG liquid. Figure IB is a schematic showing the main internal features of the Figure 1A device.

Figure 2A shows personal, portable PG vapor delivery device that is wearable device.

Figure 2B is a schematic showing the main internal features of the Figure 2A device.

Figure 3 shows the Figure 2 personal, portable PG vapor delivery device docked onto a docking station; a large PG liquid container is also docked onto the docking station; PG liquid is pumped from the large container into the personal, portable PG vapor delivery device.

Figure 4 shows the Figure 2 device being worn on a strap placed around the neck. It can form part of a face visor or mask.

Figure 5 shows a desktop PG vapour delivery device

Figure 6 shows a larger, transportable PG vapour delivery device, with wheels

Figure 7 is a portable, rechargeable PG vapour delivery device designed specifically for cleaning floors and surfaces, much like a cordless 'stick' vacuum cleaner.

Figure 8 is a lightweight, handheld PG vapour delivery device for cleaning surfaces.

Figure 9 is a PG vapour delivery device for cleaning people, pets and clothing; it is a walk through or walk-in disinfection station

Figure 10 shows a disinfection cabinet.

Figure 11A and 11B shows a personal, portable PG vapor delivery disinfection system with a form factor similar to a re-fillable nicotine e-cigarette. Figure 12 shows a typical PG liquid re-fill bottle that a consumer can purchase from a grocery store; the container includes an authentication chip or barcode.

Index

PG liquid reservoir 1

Ceramic heating plate 2

Power unit 3 power control system 4

RFID reader 5

Timer 6

Internal PG reservoir 7

Fluid transfer system 8

Ceramic or cotton wick 9

Heating plate or coil 10

Air fan 11

PG vapour outlet holes 12

Rechargeable battery 13

Capacitive sensor system 14

Docking station 15

Large PG liquid container 16

PG liquid pump 17

Data connectivity system 18

Authentication chip 20

Portable PG vapor delivery device 100

Desktop PG vapor delivery device 500

Transportable PG vapor delivery device 600

PG device for cleaning floors 700

PG tank 701

Fan 703

Extension tube 704

Floor cleaning head 705

Handheld vapor delivery device 800 PG vapour 801

Nozzle 802

Walk-through/walk-in disinfection station 900

Large liquid PG tank 901

Disinfection chamber 902

Disinfection cabinet 1000

Personal portable PG vapour delivery system 1100

Personal inhalation device 1101

Portable case 1102

Hinged holder 1103

Battery 1104

PG liquid reservoir 1105

PG liquid pump 1106

DETAILED DESCRIPTION

1. Theory for the virucidal action of PG vapour

We will start with an outline of a theory for the virucidal action of propylene glycol vapour. The propylene glycol molecule is highly hydrophilic. When the highly hydrophilic PG molecule approaches the lipid shell of an encapsulated pathogen, then the hydrophilic heads of the lipid molecules in the lipid shell are drawn to the PG molecule and the lipid membrane is disrupted and rendered ineffective. This is similar to the action of soap, but a soap molecule works by binding to the internal hydrophobic layer, and can hence only disrupt the lipid membrane if it can overcome the hydrophilic bonds binding the outer layer of the membrane together in order to reach the inner hydrophobic tails. PG on the other hand directly disrupts this outer lipid membrane. PG may be more effective than soap as a lipid membrane disrupter since soap molecules have to breach the outer lipid layer to reach the internal hydrophobic tails.

Lipid disruption may occur in the environment, for example when a PG molecule interacts with an airborne pathogen (e.g. the small droplet nuclei that is essentially a mixture of encapsulated pathogens, and some salts and proteins), or a droplet nuclei resident on a surface like a door handle etc, or skin. Because the PG is in the vapour phase, it can rapidly and, when in a fully saturated state, pervasively fill an entire room or other environment (car, plane, train, office work space, elevator, lobby etc) and contact all surfaces in that environment; typical molecular velocities in the gas phase can approach 500m per second; the additional kinetic energy PG gas phase molecules have, as compared to liquid phase molecules, may also contribute to very rapid virucidal action. Whilst it is clearly not possible to guarantee 100% pathogen destruction, a significant reduction in the viral load of anyone who is infected may well be achieved.

The virucidal action of PG vapour may be complimented or enhanced through the addition of other substances with a virucidal action. For example, like soap, nicotine may be highly effective in disrupting the lipid membrane of an encapsulated pathogen like the novel coronavirus; a nicotine molecule has a hydrophobic tail which might in theory mimic the action of a soap molecule in forcing its way through the outer hydrophilic lipid membrane layer of the pathogen in order to bond with the internal hydrophobic tails of the lipid membrane, thereby rupturing the lipid membrane and rendering it ineffective as a pathogen.

2. Advantages of propylene glycol vapour as a virucide against SARS-CoV-2 and other encapsulated pathogens

Propylene glycol vapour offers numerous practical advantages as a virucide, forming a part of the public health handling of the COVID-19 pandemic and future epidemics:

• PG is low cost and widely available, even in developing countries

• Global roll-out could be achieved rapidly and at low cost

• The mechanism for creating low concentration PG vapour is cheap, simple and can be readily improvised

• There is a plausible physical mechanism to explain virucidal action on encapsulated pathogens that are both airborne as well as on surfaces.

• PG appears to be safe and well tolerated when inhaled; the concentrations considered to be rapidly virucidal (e.g. 1 gm per 1 - 5 or 7 million cc of air) are far below the concentrations routinely and regularly inhaled by millions of e-cigarette users. There is a considerable body of scientific research on the effects of PG vapour on for example lung tissue, and this gives a sound foundation for understanding the implications of inhaling low concentration PG vapour.

• The permitted daily exposure (PDE) of inhaled PG of 50mg/Kg body weight, will not be approached; in an even aggressive scenario where someone is in a confined space for 24 hours, with a fully saturated PG atmosphere, we think it unlikely that the ingestion will exceed lmg of PG.

• The temperate at which PG vapour would be produced (e.g. 70°C - 100° C; significantly below the 188 C boiling point) is far below the temperatures at which potentially harmful formaldehydes might be generated and also far below the temperatures generated in conventional e-cigarettes (220° C to 250° C).

• Liquid disinfectants are well known and trusted by consumers for surface cleaning; persuading consumers to trust a liquid disinfectant is likely to be considerably easier than persuading consumers to trust other disinfectant techniques, like far UV-C light. Compliance with guidance on how PG should be used to achieve good results as a virucide is very important in achieving effective transmission reduction; compliance in turn is based on trust and familiarity.

3. Delivery devices.

Propylene glycol vapour offers numerous practical advantages in terms of the ease with which it can be generated. A range of different delivery devices are possible:

• A simple candle heating a plate on which PG is poured could be used - especially useful where there is no electricity

• A standard, unmodified vaporiser with a heating plate and oil/liquid reservoir, plugged directly into a power socket (like a plug-in room fragrance or oil vaporiser), but manually filled with PG rather than a water/perfumed oil mix. Automatic re filling of a PG reservoir fixed inside the vaporiser (and not user-removable), that directly feeds the heating plate, is possible, e.g. from a larger PG reservoir in the vaporiser that can be manually re-filled with PG liquid; this larger reservoir connects to a PG fluid transfer system, such as an electric pump (e.g. peristaltic pump able to handle viscous liquids like PG) or capillary tube, that transfers PG liquid to the smaller reservoir. Fan-assistance may be provided where convention is inadequate to sufficiently and rapidly distribute the PG vapour.

• A standard, unmodified fan assisted portable humidifier, e.g. wheeled steam humidifier used for increasing the humidity in a room, but manually filled with PG rather than water.

• A portable, hand-held vaporising device with a small air fan, designed to enable a user to direct a jet of PG vapour at items or specific areas of a room, car, etc. The device may be self-contained and rechargeable and manually filled with liquid PG.

• A personal vaporising device, similar to an e-cigarette, designed to be placed against the lips and inhaled. Adapted to operate at a much lower temperature (e.g. well under the 188 C boiling point, such as under 150 C, and possibly under lOOC). The device delivers far lower concentrations of inhaled PG than a conventional vaping device.

• Where the viscosity of the PG makes using a conventional humidifier or vaporising device challenging, then a PG fluid transfer system, such as an electric pump (e.g. peristaltic pump able to handle viscous liquids like PG) or capillary tube may be needed to move the PG to the heating element in the humidifier or vaporising device.

• A UV-C dis-infectant device, e.g. a mobile robot with a high intensity source of UV- C light (e.g. emitting light across 200nm to 315 nm) can also be combined with a PG vaporising system: that way, more thorough disinfection can be completed since the PG vapour reaches and disinfects surfaces that are in shadow and are hence unaffected by the UV-C. light.

One important practical aspect to deploying this technology is to communicate trust to the user that the invisible vapour produced by these devices is in fact virucidal. A major risk is that counterfeit liquids could be used that, unlike PG, have no virucidal properties; the ordinary consumer is of course unable to tell whether a liquid labelled as PG is in fact PG. To address this issue, an implementation of the invention requires that that the PG vapour delivery device can only work if filled with authenticated liquid - i.e. genuine PG. There are several ways of achieving this through simple and low cost authentication systems:

• the authentic PG liquid could be sold in bottles or containers that include an authentication chip that connects (through a contact or contactless mechanism like RFID) to the PG vapour delivery device and the device fills from the bottle or container or otherwise operates only if an authentication routine performed by the device shows that the device is genuine, e.g. based on a unique encrypted ID recorded on the authentication chip. The device could itself be a data connected device -e.g. through a Wi-Fi connection to a local Wi-Fi hub to the internet and then to a remote server; the server can store and record all unique IDs so that authentication can be denied if a unique ID is re-used on multiple different times indicative of counterfeiting.

• If the device is not a connected device, then the authentication can be done locally on the device. Some additional technique is then needed to ensure that an authentic PG liquid bottle is not subsequently filled with some illicit liquid without pathogenic properties; this could done by making the bottle non-refillable; for example, the bottle could have a one-way valve that enables PG liquid to be poured out of the bottle, but prevents some illicit liquid being poured back into the bottle. • an authentic PG liquid bottle or container can include a secure count-down chip that decrements or changes a counter each time it is used to deliver PG liquid; once a threshold is reached, the PG vapour delivery device will no longer draw PG liquid from the bottle or container; that bottle or container could be re-filled with unauthorised PG liquid, but that bottle or container would be blocked form being used by a vapour delivery device, since the device would read the count-down chip and the authentication would hence fail.

• A PG liquid bottle could include a combination of a one-way valve and also a secure count-down chip.

• authentic PG liquid could be sold in bottles or containers that include a physical design of nozzle and aperture that interfaces only with a corresponding aperture or nozzle in the PG vapour delivery device; and designed not to be user-refillable (e.g. with a secure, tamper proof cap that cannot be removed in normal use)

For ordinary consumers, these authentication mechanisms are important to build trust and confidence in the efficacy of the system; it also enables suppliers of the PG liquid to subsidise the retail cost of the PG vapour delivery device since there can be a higher degree of confidence that revenue will be earned on the consumables, namely the PG liquid itself.

We will look now in more detail at a range of PG vapour delivery devices.

Figure 1A shows the most conceptually simple variant; it is a PG vapour delivery device 100 that is light, easily portable and can sit on a desktop, floor etc.. It has a shallow, heated bowl into which a user manually pours PG liquid; the capacity is approximately lOmL and the bowl forms a PG liquid reservoir 1. It has much in common with a domestic essential oil vaporiser. A schematic diagram is at Figure IB. A ceramic heating plate 2 lies under the PG liquid reservoir 1; it is mains powered from power unit 3 and power control system 4. The device 100 is manually turned on and then heats to approx. 80C - 120C. It takes approximately 3 hours to vaporise 5mL of PG at 80C, sufficient to reach virucidal concentration of saturated PG vapour for a typical domestic room or a hospital room (e.g. for a single patient). Whilst a simple open bowl-type vaporiser is shown, the form-factor could be the same as a room freshener device that plugs directly into a power socket; then, the device would include a user-refillable reservoir into which PG liquid could be manually poured, or it could work only with factory pre-filled capsules of PG liquid.

The device 100 has a timer system 5 so that it automatically turns off after the time requires to vaporise the recommended amount of PG poured into the bowl. The device 100 includes an RFID reader 6 that detects whether an authentic RFID tag, from an external PG liquid container, was detected within a time, say 5 minutes, before or after the device 100 was turned on to start heating; only authorised PG bottles or containers (see Figure 11) include this authentic tag and hence the device 100 will only work if the device 100 has detected the presence of an authorised PG bottle.

Figure 2A is a personal, portable PG vapor delivery device 100, shown schematically in Figure 2B. It is a wearable device; it clips on to a belt, or can be worn around the neck; it can be held and directed at surfaces, items etc to be cleansed. The device 100 has an internal 50mL PG liquid reservoir 7, a fluid transfer system 8 to feed PG liquid to a PG wick, such as a ceramic wick or cotton wick 9 to absorb PG liquid; the ceramic or cotton wick 9 is heated by the PG heating system 10 (e.g. heating coil that reach 80C or higher, e.g. 120C). These heating systems can be the same as the heating systems used in e-cigarettes: for example, a simple metal coil wound around the ceramic or cotton wick, or a small metal plates adjacent to the wick. The system can include a small fan 11 blowing air over the PG soaked wick 9 and through PG vapour outlet holes 12. The device 100 is self-contained and is powered by a rechargeable battery 13. Much of the technology is re-purposed from the e-cigarette or vaping world (which is non-analogous to the infection control field to which this invention relates). Reference may be made to vaping-related patent applications, such as US 9,883,697, US2020/0214352A1, US10285449, PCT/GB2019/052922, the contents of which are incorporated by reference.

The internal PG reservoir 7 that feeds PG soaked wick 9 can be manually re-filled with PG liquid by the user opening a small filling cap in the side of the device and pouring PG liquid into the reservoir 7. The device 100 can include a PG liquid authentication system as described above; for example, a RFID chip reader 5 that permits operation of the device only if it has detected the presence of an authenticated PG container 16 (not shown) within a certain time (e.g. 1 minute) of the internal reservoir 7 in the device being replenished; replenishment can be automatically detected by a simple capacitive liquid level sensor 14 (the flat, parallel capacitive plates of this sensor system are shown in Figure 2) in or outside the internal reservoir 7 which is set up to detect when liquid is added to the internal reservoir 7, i.e. the level of the PG liquid in the reservoir 7. the capacitive sensor system 14 could include a pair of opposed capacitive plates in or surrounding the internal reservoir 7; a circuit part of the system 14 measures the capacitance, which increases as the internal reservoir 7 is filled with PG liquid and infers the PG liquid level or amount from that.

Capacitive sensor system 14 can also detect when the level drops below a threshold amount and that can trigger an alert, such as a warning light on the device 100. If the device 100 is data-connected, e.g. via Bluetooth to a user's smartphone or other computing device, then the current liquid level in the reservoir 7, as measured by the capacitive sensor system 14, can be sent for display on the smartphone etc. and can be used to prompt for, or initiate, automatic ordering and delivery if fresh supplies of PG liquid. The device 100 records and stores when it has been used, the temperature of the heating plates or coil 10 (generally inferred from the current used, and hence the resistance, and hence the temperature, given the temperature coefficient of resistivity of the coil), the amount of PG liquid consumed and hence vaporised; this data can be very useful if the device is used as part of any clinical trials testing the impact of the device 100 in reducing real-world pathogen transmission rates. All of this data can be shared with or sent to a remote server, where this data can be analysed.

The device 100 can also be electrically re-charged at a docking station 15 (shown in Figure 3) that has (i) a much larger (e.g. 21 or more) PG bottle or container 16 docked into it and (ii) a pump 17 to automatically transfer PG from the container 16 to the internal reservoir 7 in the device 100. The pump 17 could be a peristaltic pump or a piston pump; reference to US2020/0214352A1 may be made. The solid arrows indicate the liquid PG flow path.

PG bottle or container 16 is hence the primary consumable a user regularly buys (e.g. online or from a regular grocery store, next to conventional surface disinfectants). The container 16 (see also Figure 11) can be placed on or into the docking station 15 and mechanically interfaced with the docking station 15. For example, a filling needle in the docking station 15 can be moved (automatically or manually) to penetrate a self-sealing rubber septum in the base of the wall of the container 16 so that PG liquid can be withdrawn from container 16 by electric PG liquid pump 17 and pumped to the internal PG reservoir 7 in the vapour generating device. The capacitive liquid level sensing system 14 plays a key role here, since it controls the operation of the PG liquid pump 17; it ensures that the PG liquid pump 17 stops pumping once the internal PG reservoir 7 has reached its fully filled state. More details on suitable capacitive liquid level sensing systems, the closed feedback loop constant temperature driver, and authentication and data connectivity system can be found for example in PCT/GB2019/052922.

The much larger PG bottle or container 16 could include any of the authentication mechanisms described above - e.g. it could include an authentication chip 20 with a unique ID that is read by a chip reader 5 in the docking station 15 and the PG liquid pump 17 in the docking station 15 then only withdraws liquid from the large PG reservoir or bottle 16 if the authentication process is passed - e.g. the ID is valid. The desktop dock can include a data connectivity system 18 so that it can verify the authentication data supplied by the bottle, for example using a cloud-based server that stores lists of valid IDs and/or invalid IDs or any other authentication system.

This personal, portable device 100 is useful where specific surfaces or small spaces require immediate disinfection - for example, surfaces and the air inside a relatively small environment in which there may have been an infectious person or a person with pathogens on their hair, skin or clothing: an ambulance or car carrying an infected person; toilets and toilet cubicles in hospitals; changing rooms in a hospital where medical staff change out of PPE.

Refillability from a large bottle of PG 16 using the automatic refilling provided by the docking station 15 gives greater convenience and economy, and assurance that the device 100, if it starts to run low on PG liquid, can be readily and rapidly re-filled at a docking station 15. In some settings, e.g. hospitals, ambulances, it will be convenient to deploy large numbers of these docking station 15, each complete with large PG containers 16, so that staff using the personal devices 100 can easily re-fill those devices with PG liquid.

Figure 3 shows the Figure 2 device 100 being worn on a strap placed around the neck. The device 100 can feed PG vapour to the space between a visor and the face when used in high risk environments where a visor is needed (e.g. hospitals, ambulances etc). The device 100 may be physically integrated into a visor. The form or shape of the device can be radically altered without affecting its operation: it could for example be shaped so that it wraps around the neck, much like a large item of neck jewellery.

The description of the remaining devices shown in Figures 4 - 10 will be abbreviated because all operate in substantially the same manner as the Figure 2 device. Their physical shape, or form factor, differ, but their fundamental operation remains as described for the Figure 2 and 3 implementation.

Figure 5 is a desktop PG vapour delivery device 500. It has a 1L re-fillable PG tank, an electric pump to transfer PG liquid to the heating system (as described above) and a fan to blow the PG vapour out from grill-type vapour outlet 12; it is mains powered. It can also re charge and re-fill with liquid PG a portable, personal PG vapour device (e.g. the device shown in Figure 2 and 3), which docks into the top of the desktop unit. The device 500 also acts as an air cleaner, sucking air in from the environment, passing it through a HEPA filter, and blowing the clean air through the PG liquid heating system and out through grill-type vapour outlet 12. When the PG liquid heating system is activated, the air blown out of the device will included PG vapour; when it is not activated, the air is simply air that has been cleaned by the HEPA filter.

Figure 6 is a larger, transportable PG vapour delivery device 600, on wheels. It can be moved from room to room and is hence more suitable where rooms need to be regularly disinfected (e.g. patient rooms, waiting areas, toilets, changing rooms in hospitals; office conference rooms, office toilets, office waiting areas; in the military context, barracks, toilets, changing rooms, briefing rooms).

It has a large internal 5L re-fillable PG tank, an electric pump to transfer PG liquid to the heating system and a fan to blow the PG vapour out from outlets 12; it is mains powered. It can also re-charge and re-fill with PG liquid a portable, personal PG vapour device (e.g. as shown in Figure 2 or 3), which docks into the top of the unit. This device could include a UV-C light source, e.g. emitting light across 200nm to 315 nm range (not shown); the PG vapour reaches and disinfects surfaces that are in shadow and are hence unaffected by the UV-C light; the UV-C light compliments the pathogenic action of the PG vapour on pathogenic airborne droplet nuclei and on contaminated surfaces. Device 600 can also include a HEPA filter system, as described for the Figure 5 device. Figure 7 is a portable, rechargeable PG vapour delivery device 700 and designed specifically for cleaning floors and surfaces, much like a cordless 'stick' vacuum cleaner. It has a 1L re- fillable liquid PG tank 701, electric pump to transfer PG liquid to the internal heating system and a fan 703 to blow the PG vapour out through the extension tube 704 nozzle to the floor cleaning head 705; various nozzle attachments are possible, just as with a stick vacuum cleaner. The device 700 is powered by a rechargeable battery and can also be mains powered.

Figure 8 is a lightweight, handheld PG vapour delivery device 800 for cleaning surfaces. It is similar in shape to a rechargeable, handheld vacuum cleaner. It has a 1L re-fillable PG tank 801 wick or electric pump to transfer PG liquid to the heating system and a fan to blow the PG vapour out through a head 802. It is powered by a rechargeable battery and can also be mains powered.

Figure 9 is a PG vapour delivery device for cleaning people, pets and clothing; it is a walk through or walk-in disinfection station 900. It has a 50L re-fillable PG tank 901, electric pump to transfer PG liquid to the heating system and a fan to blow the PG vapour into the disinfection chamber 902 that people stand in or walk through. Timed doors can be provided to ensure that a person stays in the chamber for sufficient time for viruses to be destroyed (typically 30 seconds). The chamber can be used where ever there is a need to sanitise people before they enter a building etc- e.g. at the entrances to hospitals, offices, transport facilities, shopping centres, hotels, restaurants, airports, train stations.

Figure 10 shows a disinfection cabinet 1000. It has a 1L re-fillable PGtank, electric pump to transfer PG liquid to the heating system and a fan to blow the PG vapour into the chamber once the door is shut. Items including food items, or shopping, or mobile phones, payment cards etc can be rapidly disinfected. Alternatively, one of the portable devices described above (e.g. in Figure 1 - 3) can be simply placed inside the chamber (typically the size of a domestic microwave oven (e.g. capacity of between 10L and 40L), together with the items to be sanitised ( e.g. mobile phones, credit cards, pens and pencils, coins and notes, food items, packaged food items - anything that might have been handled by someone), the device activated and the door closed. All of the above devices may include a timer, which the user can set so that the device heats for 1 hour, 2 hour or 3 hours etc. It may also include a ‘boost’ function, which increases the temperature of the heating element from 80C to 120C for a pre-set time (e.g. 15 minutes, or 30 minutes, or an hour etc). The fan may activate only in ‘boost’ mode, or be separately activated.

Figure 11A and 11B shows a personal, portable PG vapor delivery disinfection system 1100 with a form factor similar to a re-fillable nicotine e-cigarette. The system includes a personal inhalation device 1101, shaped like a cigarette or e-cigarette, and a case 1102 that the personal inhalation device 1101 slides into for storage and re-filling. The case 1102 includes a hinged holder 1103 that hinges open to receive the device 1101 for storage, re-filling with PG liquid, and re-charging a battery 1104 in the device 1101. Alternatively, the personal inhalation device 1101 can slide down into an aperture in the case.

The system 1100 has a user-replaceable lOmL PG liquid reservoir 1105 that slots into the case 1102, a small peristaltic pump 1106 to transfer liquid PG from the reservoir 1105 to a PG heating system in the personal inhalation device 1101. The system is designed for sanitising the respiratory tract and lungs, as opposed to delivering addictive nicotine. Personal inhalation device 1101 can also be re-filled and re-charged at a docking station (not shown) that has a much larger (e.g. 500ml PG reservoir) and a pump to transfer the PG liquid to a small internal reservoir in the personal portable PG vapour device.

With all of the devices described above, the PG liquid capacities merely relate to one implementation; different capacities are naturally possible and readily determined according to the specific requirements of the device.

Integration into an HVAC system (e.g. domestic, or for a large office, factory, shopping centre, or even laboratories handling pathogens, such as labs with biosafety level 3 or 4 categorisation etc) is also possible: large heating plates, fed by a large (e.g. 1000L capacity PG reservoir) that pumps PG liquid onto the heating plates are positioned in the direct airflow generated by the HVAC system.

Figure 12 shows a typical PG liquid re-fill bottle 16 that a consumer can purchase from a grocery store. Virucidal action is highly dependent on the liquid being used by the vaporising devices described above, and that there is a real danger of counterfeit liquids, or liquids that appear to be PG, but are in fact something different. So the PG liquid re-fill bottle includes a very low-cost RFID chip 20 to authenticate that bottle to the PG vapour delivery device whose PG reservoir it is re-filling..

Additional Use Cases

In this section, we outline some enhancements to the system and PG disinfection devices described above.

A block chain distributed ledger could be used for secure tracking of PG - e.g. to track PG bottles through the supply chain, record their consumption or useage data.

PG liquids and also vapour could be given a specific sent (e.g. a fragrance) smell and/or colour so that users would be aware that a PG disinfection device was operating correctly (PG vapour is colourless and odourless).

A PG disinfection device could:

• could include a mosquito repellent system.

• be integrated into a case for a mobile phone or laptop

• be integrated into a fire suppression sprinkler system

• be integrated into a back pack or other bag or case, with a PG vapour outlet connecting via a flexible pipe to a visor or mask

• be integrated into a wearable device such as a bracelet or watch

• be integrated into a light fitting or smoke alarm

• be integrated into a dehumidifier

• be integrated into an Air amplifier (bladeless air fan)

• could be integrated into a hand sanitizer station

• could be integrated into an automated fragrance dispenser , e.g. as used in in a toilet cubicle, bank of toilet cubicles or a restroom

• could be integrated into a bidet or combined toilet/bidet

Efficacy data We incorporate by reference the efficacy data published in US patent 2,333,124 and 'The bactericidal action of propylene glycol vapor on microorganisms suspended in air. I. and II. J Exp Med. 1942 Jun 1; 75(6): 593-610. doi: 10.1084/jem.75.6.593. and J Exp Med. 1943 Nov 1; 78(5): 387-406. doi: 1Q.1084/iem.78.5.387.

For each of the above implementations, a degree of routine testing is required for regulatory compliance and certification; for example, testing would verify the following parameters:

• optimal operating temperature (70 C - 90C) for virucidal action against specific pathogens

• typical PG consumption rates for different room sizes (lgm to 20 gm for a room sized 5m x 3m x 3m is typical)

• whether convection is adequate or fan-based assistance is needed

• how long PG vapour concentrations are maintained with and without operation of the delivery device in typical environments, so that workable guidance can be given (e.g. - for a room of plan size 5m x 3m x 3m, then 5gm delivered by operating a low- wattage plug-in room vaporiser for 1 hour a day would likely be sufficient).

• the range of PG vapour concentrations that are virucidal (lgm of PG to 1 million - 10 million cc air is likely effective)

• how long the virucidal action takes and the relationship between vapour concentration and action time - (virtually instantaneous at higher concentrations, such as lgm of PG to 1 million cc air)

We have described the use of PG, but other glycols, such as triehtylene glycol can also be used instead, or in combination. Other additives include: scent; nicotine, vegetable glycerine (to increase the visible vapour cloud). Adding water is likely to be undesirable: water reduces the virucidal effect of the PG vapour, because the PG molecules selectively bond with water molecules, as opposed to the pathogen lipid shell. Appendix 1

Key features

A disinfection device configured to create a virucidal propylene glycol vapour to reduce encapsulated pathogen fomite transmission and also droplet nuclei transmission; the device including (a) a liquid propylene glycol reservoir; (b) a heater or atomiser configured to heat or transform liquid propylene glycol into a vapour; (c) a power source or connection to an external power source, to power the heater or atomiser; (d) a control system to control the power source and the heater or atomiser; and (e) an authentication mechanism configured to automatically authenticate a source of liquid PG for use in the device.

Optional features (any feature can be combined with any other feature)

Authentication

• the disinfection device includes an authentication mechanism configured to automatically disable the device unless it is filled with PG liquid from a source that has passed an authentication process.

• the authentication mechanism is configured to automatically permit the disinfection device to use liquid PG from an external source if authentication is passed.

• the source is a PG liquid bottle or container including an authentication device or object

• The propylene glycol liquid container includes an authentication chip, memory, barcode, optically readable glyph, or other data store and the device reads that data store and automatically determines if the container is authentic.

• the authentication device or object is a chip, RFID chip, barcode, glyph, or other data carrier storing an ID and the disinfection device reads the data carrier and undertakes an authentication process in respect of the ID.

• an authentication chip on a PG liquid container includes a counter that alters each time the container is used and the authentication chip automatically locks when a threshold value is reached, preventing the device from using the locked container.

• The vaporising device is configured to attach or connect to a propylene glycol liquid container that is configured to be a single use item and not be user-refillable. • The propylene glycol liquid bottle or container is not user-refillable by virtue of including a one-way valve that permits PG liquid to be poured from the liquid bottle or container but not for a liquid to be poured back into the container.

• The vaporising device includes a propylene glycol reservoir and a liquid filling mechanism configured to engage with or be filled from a liquid re-fill bottle or container that does not have an open mouth but instead has a liquid pouring mechanism that locks or otherwise securely engages with the liquid filling mechanism.

Disinfection Device Form factors

• The vaporising device is a portable device that is self-contained, including a rechargeable power source to power the atomiser or heater.

• The vaporising device is a portable, personal, device configured to be worn or attached to an item of clothing and to provide propylene glycol vapour around the user's eyes, and/or nose and/or mouth.

• The vaporising device is a portable, personal, device configured to be worn or attached to a face mask, respirator or visor.

• The vaporising device is a portable, personal, device configured to be placed into a docking station for re-charging a battery in the device.

• The vaporising device is a portable device configured to be placed into a docking station for re-charging a battery in the device and re-filling with propylene glycol from a reservoir, bottle or container of PG liquid that is attached to or docked with the docking station.

• The vaporising device is a portable device configured to be placed on a desk or worktop or floor and is mains powered.

• The vaporising device includes a fan to blow air over the heating element or atomising to increase the rate at which propylene glycol vapour is formed

• The vaporising device is a transportable device with wheels, configured to be moved between locations

• The vaporising device has the shape or configuration of a stick-type vacuum cleaner.

• The vaporising device has the shape or configuration of a handheld' vacuum cleaner.

• The vaporising device is configured to feed propylene glycol vapour into a sealable chamber into which one or more objects can be placed. • The vaporising device includes a sealable chamber into which one or more objects can be placed for disinfection.

• The vaporising device is configured to feed propylene glycol vapour into a walk-in or walk-through disinfection station

Disinfection Device structure

• The vaporising device includes a liquid level or liquid quantity measuring system configured to automatically measure, directly or indirectly, the level or quantity of propylene glycol in a PG liquid reservoir in the device.

• the liquid level or liquid quantity measuring system automatically generates an alert if the level or quantity of PG liquid in the device falls below a threshold.

• the alert is sent to a connected app, such as a smartphone app.

• The vaporising device includes a fluid transfer system configured to automatically transfer liquid propylene glycol from a PG liquid reservoir to the heater or atomiser;

• The vaporising device includes a heating or atomising element, a propylene glycol liquid reservoir, and a wick configured to feed propylene glycol liquid from the reservoir to the heating or atomising element and a power source for the heating or atomising element.

• The vaporising device includes a timer operable to set the time interval for which the device is automatically powering the heating or atomising element

• The vaporising device includes a timer operable to set the time of day or night during which the device is automatically powering the heating or atomising element.

• The vaporising device includes a fan configured to blow air over the heating or atomising element to increase the rate at which propylene glycol vapour is formed.

• The vaporising device includes a fan configured to blow air over the heating or atomising element to increase the rate at which propylene glycol vapour is formed and which, when the fan is activated, the device also automatically increases the energy supplied to the heating or atomising element.

• The vaporising device includes an electrically powered or controlled pump to transfer liquid from the PG liquid reservoir to a PG heating or atomising system.

• The vaporising device includes an atomiser that is a piezo-electric atomiser.

• The vaporising device includes an atomiser that comprises a porous ceramic wick with a heating plate or coil formed in or around the ceramic wick. • The device includes a rechargeable electrical power source.

• The vaporising device is combined with a UV-C light source

• The vaporising device is combined with a HEPA air purifying system and/or a UV-C light source.

Heating system

• The personal vaping device includes a heating system that generates gas phase propylene glycol.

• The personal vaping device includes a heating system that is made up of one or more resistively heated plates or other structures.

• The personal vaping device includes a heating system that is combined with a piezo electric atomiser.

• The personal vaping device includes a closed feedback loop, constant temperature driver, designed to heat an atomiser to a desired temperature and maintain it at that temperature.

• The personal vaping device includes an atomiser arranged to heat the propylene glycol solution to a temperature of less than the 188 degree boiling point of PG.

• The personal vaping device includes an atomiser arranged to heat the propylene glycol solution to a temperature of between 120C and lOOC.

• The personal vaping device includes an atomiser arranged to heat the propylene glycol solution to a temperature of less than the 100 degrees C boiling point of water.

• The personal vaping device includes an atomiser arranged to heat the propylene glycol solution to a temperature of between 90 degrees C and 60 degrees C.

• The personal vaping device includes an atomiser arranged to heat the propylene glycol solution to a temperature of between 80 degrees C and 60 degrees C.

• The personal vaping device includes an atomiser arranged to heat the propylene glycol solution to a temperature of between 70 degrees C and 60 degrees C.

• The personal vaping device includes an atomiser arranged to heat the propylene glycol solution to a temperature of less than 60 degrees C.

Liquid

The propylene glycol liquid is not mixed or combined with any other substances • The propylene glycol liquid is mixed with vegetable glycerine.

• The propylene glycol liquid is mixed with nicotine or a nicotine salt.

• The propylene glycol liquid does not include potentially addictive levels of nicotine

• The propylene glycol liquid is mixed with a fragrance or perfume.

• The propylene glycol liquid includes substantially no water

• The propylene glycol liquid is replaced in whole or part by triethylene glycol.

Vapour properties

• the vapour is of density sufficient to destroy or reduce the numbers of encapsulated pathogens that are on surfaces and that are airborne, and hence simultaneously target fomite transmission and also airborne transmission and yet be safe for humans to inhale

• the vapour destroys pathogens through the hydrophilic action of propylene glycol molecules disrupting the hydrophilic outer layer of the lipid membrane of the encapsulated pathogens.

• The vapour density is lgm per 1 to 1 million cc of air.

• The vapour density is lgm per 1 to 5 million cc of air.

• The vapour density is lgm per 1 to 10 million cc of air.

• The vapour is a saturated vapour.

• The vapour density is selected to be safe for humans to inhale when in the vicinity of the device to remove the need to evacuate humans from the environment where the device is in operation

• The vapour density is selected to be safe for humans to inhale so that they can continue normal activities in the environment containing the dilute propylene glycol vapour

• The vapour density is selected to be safe for humans to inhale over a defined time period.

• The vapour density is selected to be safe for humans to inhale over a time period exceeding 1 hour

• The vapour density is selected to be safe for humans to inhale over a time period exceeding 5 hours.

• The vapour density is selected to be safe for humans to inhale over a time period exceeding 8 hours. The vapour density is selected to be safe for electrical equipment

Other optional features

• The encapsulated pathogen can be any of: SARS-CoV-2; coronaviruses, common cold, influenza, H.I.V., viruses that cause Ebola, hepatitis B and C, herpes, Zika, dengue.

• The encapsulated pathogen is airborne.

• The encapsulated pathogen is on a surface.

Other aspects

A disinfection device configured to create a virucidal propylene glycol vapour for reducing encapsulated pathogen fomite transmission and also droplet nuclei transmission; the device including (a) a liquid propylene glycol reservoir; (b) a heater or atomiser configured to heat liquid propylene glycol to form a vapour; (c) a power source or connection to an external power source, to power the heater or atomiser; (d) a control system to control the power source and the heater or atomiser.

A vaporising device configured to create a dilute propylene glycol vapour of density of lgm per 1 to 7 million cc of air to destroy encapsulated pathogens, where the device is a humidifier for increasing the humidity in an environment or a vaporiser; the humidifier or vaporiser including (i) and an atomising or vapourisation system and (ii) a reservoir containing a propylene glycol liquid of a concentration suitable for creating that propylene glycol vapour of density of lgm per 1 to 7 million cc of air to destroy pathogens through the hydrophilic action of propylene glycol molecules disrupting the hydrophilic outer layer of the lipid membrane of the encapsulated pathogens.

A vaporising device configured to create a dilute propylene glycol vapour of density of lgm per 1 to 7 million cc of air to destroy encapsulated pathogens, where the device is an e- cigarette or other personal, portable vaping device, including (i) and an atomising or vapourisation system and (ii) a reservoir containing a propylene glycol liquid of a concentration suitable for creating that propylene glycol vapour of density of lgm per 1 to 7 million cc of air, to destroy the encapsulated pathogens through the hydrophilic action of propylene glycol molecules disrupting the hydrophilic outer layer of the lipid membrane of the encapsulated pathogens.

A method for destroying encapsulated pathogens using an e-cigarette or other personal, portable vaping device, comprising the steps of:

(i) supplying, from a reservoir, a propylene glycol liquid of a concentration suitable for creating propylene glycol vapour of density of lgm per 1 to 7 million cc of air;

(ii) using that PG liquid in an atomising or vapourisation system to create that PG vapour from the personal, portable vaping device;

(iii) enabling a human to inhale that vapour to enable encapsulated pathogens to be destroyed by virtue of the hydrophilic properties of the propylene glycol molecule disrupting the hydrophilic lipid membrane of the encapsulated pathogen.

A disinfection method comprising the steps of:

(iii) activating a heater or atomiser in the device, the heater or atomiser configured to heat or transform liquid propylene glycol into a vapour, if the authentication is passed.

Claims

1. A disinfection device configured to create a virucidal propylene glycol vapour to reduce encapsulated pathogen fomite transmission and also pathogen droplet nuclei transmission; the device including (a) a liquid propylene glycol reservoir; (b) a heater or atomiser configured to heat or transform liquid propylene glycol into a vapour; (c) a power source or connection to an external power source, to power the heater or atomiser; (d) a control system to control the power source and the heater or atomiser; and (e) an authentication mechanism configured to automatically authenticate a source of liquid PG for use in the device.

Authentication

2. The disinfection device of Claim 1 in which the authentication mechanism is configured to automatically disable the device unless it is filled with PG liquid from a source that has passed an authentication process.

3. The disinfection device of Claim 1 or 2 in which the authentication mechanism is configured to automatically permit the disinfection device to use liquid PG from an external source if authentication is passed.

4. The disinfection device of any preceding Claim in which the source is a PG liquid bottle or container including an authentication device or object.

5. The disinfection device of preceding Claim 4 in which the propylene glycol liquid container includes an authentication chip, memory, barcode, optically readable glyph, or other data store and the device reads that data store and automatically determines if the container is authentic.

6. The disinfection device of any preceding Claim in which the authentication device or object is a chip, RFID chip, barcode, glyph, or other data carrier storing an ID and the disinfection device reads the data carrier and undertakes an authentication process in respect of the ID.

7. The disinfection device of any preceding Claim in which an authentication chip on a PG liquid container includes a counter that alters each time the container is used and the authentication chip automatically locks when a threshold value is reached, preventing the device from using the locked container.

8. The disinfection device of any preceding Claim which is configured to attach or connect to a propylene glycol liquid container that is configured to be a single use item and not be user-refillable.

9. The disinfection device of preceding Claim 8 in which the propylene glycol liquid bottle or container is not user-refillable by virtue of including a one-way valve that permits PG liquid to be poured from the liquid bottle or container but not for a liquid to be poured back into the container.

10. The disinfection device of any preceding Claim in which device includes a propylene glycol reservoir and a liquid filling mechanism configured to engage with or be filled from a liquid re-fill bottle or container that does not have an open mouth but instead has a liquid pouring mechanism that locks or otherwise securely engages with the liquid filling mechanism.

Disinfection Device Form factors

11. The disinfection device of any preceding Claim 1 - 10 which is a portable device that is self-contained, including a rechargeable power source to power the atomiser or heater.

12. The disinfection device of any preceding Claim 1 - 11 which includes a fan to blow air over the heating element or atomising to increase the rate at which propylene glycol vapour is formed.

13. The disinfection device of any preceding Claim 1 - 12 which is a portable, personal, device configured to be worn or attached to an item of clothing and to provide propylene glycol vapour around the user's eyes, and/or nose and/or mouth.

14. The disinfection device of any preceding Claim 1 - 13 which is a portable, personal, device configured to be worn or attached to a face mask, respirator or visor.

15. The disinfection device of any preceding Claim 1 - 14 which is a portable, personal, device configured to be placed into a docking station for re-charging a battery in the device.

16. The disinfection device of any preceding Claim 1 - 15 which is a portable device configured to be placed into a docking station for re-charging a battery in the device and re filling with propylene glycol from a reservoir, bottle or container of PG liquid that is attached to or docked with the docking station.

17. The disinfection device of any preceding Claim 1 - 12 which is a portable device configured to be placed on a desk or worktop or floor and is mains powered.

18. The disinfection device of any preceding Claim 1 - 12 which is a transportable device with wheels, configured to be moved between locations.

19. The disinfection device of any preceding Claim 1 - 12 which has the shape or configuration of a stick-type vacuum cleaner.

20. The disinfection device of any preceding Claim 1 - 12 which has the shape or configuration of a handheld' vacuum cleaner.

21. The disinfection device of any preceding Claim 1 - 12 which is configured to feed propylene glycol vapour into a sealable chamber into which one or more objects can be placed.

22. The disinfection device of any preceding Claim 1 - 12 which includes a sealable chamber into which one or more objects can be placed for disinfection.

23. The disinfection device of any preceding Claim 1 - 12 which is configured to feed propylene glycol vapour into a walk-in or walk-through disinfection station

Disinfection Device structure

24. The disinfection device of any preceding Claim which includes a liquid level or liquid quantity measuring system configured to automatically measure, directly or indirectly, the level or quantity of propylene glycol in a PG liquid reservoir in the device.

25. The disinfection device of ay preceding Claim 24 in which the liquid level or liquid quantity measuring system automatically generates an alert if the level or quantity of PG liquid in the device falls below a threshold.

26. The disinfection device of any preceding Claim 25 which the alert is sent to a connected app, such as a smartphone app.

27. The disinfection device of any preceding Claim which includes a fluid transfer system configured to automatically transfer liquid propylene glycol from a PG liquid reservoir to the heater or atomiser.

28. The disinfection device of any preceding Claim which includes a heating or atomising element, a propylene glycol liquid reservoir, and a wick configured to feed propylene glycol liquid from the reservoir to the heating or atomising element and a power source for the heater or atomiser.

29. The disinfection device of any preceding Claim which includes a timer operable to set the time interval for which the device is automatically powering the heater or atomiser.

30. The disinfection device of any preceding Claim which includes a timer operable to set the time of day or night during which the device is automatically powering the heater or atomiser.

31. The disinfection device of any preceding Claim which includes a fan configured to blow air over the heater or atomiser to increase the rate at which propylene glycol vapour is formed.

32. The disinfection device of any preceding Claim which includes a fan configured to blow air over the heater or atomiser to increase the rate at which propylene glycol vapour is formed and which, when the fan is activated, the device also automatically increases the energy supplied to the heater or atomiser.

33. The disinfection device of any preceding Claim which includes an electrically powered or controlled pump to transfer liquid from the PG liquid reservoir to the heater or atomiser.

34. The disinfection device of any preceding Claim which includes an atomiser that is a piezo-electric atomiser.

35. The disinfection device of any preceding Claim which includes an atomiser that comprises a porous ceramic wick with a heating plate or coil formed in or around the ceramic wick.

36. The disinfection device of any preceding Claim which includes a rechargeable electrical power source.

37. The disinfection device of any preceding Claim which is combined with a UV-C light source.

38. The disinfection device of any preceding Claim which is combined with a HEPA air purifying system and/or a UV-C light source.

Heating system

39. The disinfection device of any preceding Claim in which the heater or atomiser generates gas phase propylene glycol.

40. The disinfection device of any preceding Claim in which the heater or atomiser is made up of one or more resistively heated plates or other structures.

41. The disinfection device of any preceding Claim in which the heater or atomiser is combined with a piezo-electric atomiser.

42. The disinfection device of any preceding Claim in which the heater or atomiser includes a closed feedback loop, constant temperature driver, designed to heat an atomiser to a desired temperature and maintain it at that temperature.

43. The disinfection device of any preceding Claim in which the heater or atomiser is arranged to heat the propylene glycol liquid to a temperature of less than the 188 degree boiling point of PG.

44. The disinfection device of any preceding Claim in which the heater or atomiser is arranged to heat the propylene glycol liquid to a temperature of between 120C and lOOC.

45. The disinfection device of any preceding Claim in which the heater or atomiser is arranged to heat the propylene glycol liquid to a temperature of less than the 100 degrees C boiling point of water.

46. The disinfection device of any preceding Claim in which the heater or atomiser is arranged to heat the propylene glycol liquid to a temperature of between 90 degrees C and 60 degrees C.

47. The disinfection device of any preceding Claim in which the heater or atomiser is arranged to heat the propylene glycol liquid to a temperature of between 80 degrees C and 60 degrees C.

48. The disinfection device of any preceding Claim in which the heater or atomiser is arranged to heat the propylene glycol liquid to a temperature of between 70 degrees C and 60 degrees C.

49. The disinfection device of any preceding Claim in which the heater or atomiser is arranged to heat the propylene glycol liquid to a temperature of less than 60 degrees C.

Liquid

50. The disinfection device of any preceding Claim in which the propylene glycol liquid is not mixed or combined with any other substance.

51. The disinfection device of any preceding Claim in which the propylene glycol liquid is mixed with vegetable glycerine.

52. The disinfection device of any preceding Claim in which the propylene glycol liquid is mixed with nicotine or a nicotine salt.

53. The disinfection device of any preceding Claim in which the propylene glycol liquid does not include potentially addictive levels of nicotine.

54. The disinfection device of any preceding Claim in which the propylene glycol liquid is mixed with a fragrance or perfume.

55. The disinfection device of any preceding Claim in which the propylene glycol liquid includes substantially no water.

56. The disinfection device of any preceding Claim in which the propylene glycol liquid is replaced in whole or part by triethylene glycol.

Vapour properties

57. The disinfection device of any preceding Claim in which the propylene glycol vapour is of density sufficient to destroy or reduce the numbers of encapsulated pathogens that are on surfaces and that are airborne, and hence simultaneously target fomite transmission and also airborne transmission and yet be safe for humans to inhale

58. The disinfection device of any preceding Claim in which the propylene glycol vapour destroys pathogens through the hydrophilic action of propylene glycol molecules disrupting the hydrophilic outer layer of the lipid membrane of the encapsulated pathogens.

59. The disinfection device of any preceding Claim in which the propylene glycol vapour density is lgm per 1 to 1 million cc of air.

60. The disinfection device of any preceding Claim in which the propylene glycol vapour density is lgm per 1 to 5 million cc of air.

61. The disinfection device of any preceding Claim in which the propylene glycol vapour density is lgm per 1 to 10 million cc of air.

62. The disinfection device of any preceding Claim in which the propylene glycol vapour is a saturated vapour.

63. The disinfection device of any preceding Claim in which the propylene glycol vapour density is selected to be safe for humans to inhale when in the vicinity of the device to remove the need to evacuate humans from the environment where the device is in operation.

64. The disinfection device of any preceding Claim in which the propylene glycol vapour density is selected to be safe for humans to inhale so that they can continue normal activities in the environment containing the dilute propylene glycol vapour.

65. The disinfection device of any preceding Claim in which the propylene glycol vapour density is selected to be safe for humans to inhale over a defined time period

66. The disinfection device of any preceding Claim in which the propylene glycol vapour density is selected to be safe for humans to inhale over a time period exceeding 1 hour

67. The disinfection device of any preceding Claim in which the propylene glycol vapour density is selected to be safe for humans to inhale over a time period exceeding 5 hours.

68. The disinfection device of any preceding Claim in which the propylene glycol vapour density is selected to be safe for humans to inhale over a time period exceeding 8 hours.

69. The disinfection device of any preceding Claim in which the propylene glycol vapour density is selected to be safe for electrical equipment

Other features

70. The disinfection device of any preceding Claim in which the encapsulated pathogen is any of: SARS-CoV-2; coronaviruses, common cold, influenza, H.I.V., viruses that cause Ebola, hepatitis B and C, herpes, Zika, dengue.

Other aspects

71. A disinfection device configured to create a virucidal propylene glycol vapour for reducing encapsulated pathogen fomite transmission and also droplet nuclei transmission; the device including (a) a liquid propylene glycol reservoir; (b) a heater or atomiser configured to heat liquid propylene glycol to form a vapour; (c) a power source or connection to an external power source, to power the heater or atomiser; (d) a control system to control the power source and the heater or atomiser.

72. A disinfection method comprising the steps of: