Rotational Disinfectant Device and Method for Capturing and Disinfecting Infectants from a Gas

Abstract

A device and method for capturing and disinfecting infectants including viruses such as SARS-CoV-2 and bacteria from a gas is described. The rotational disinfectant device includes means for transmitting the infectant-containing gas to a gas inlet of a housing, which housing has a gas outlet, a disinfectant liquid inlet and a disinfectant liquid outlet; a rotor mounted for rotation in said housing and connecting to the inlets and outlets, the rotor including a plurality of disinfecting channels extending axially and parallel to a common rotation axis; and means for rotating the rotor. A disinfectant liquid collector connects to the disinfectant liquid outlet and to a return conduit that connects with the disinfectant liquid inlet. A pump transfers disinfectant liquid from the disinfectant liquid collector to the disinfectant liquid inlet through the return conduit for re-use. The return conduit, the liquid collector outlet and the disinfectant liquid inlet form a closed fluid circuit. A plurality of interconnected devices may also be used. The device and method provide an efficient means for capturing and disinfecting said infectants from a gas in order to prevent their spread.

Claims

1. A rotational disinfectant device for capturing and disinfecting infectants, comprising viruses, such as SARS-CoV-2, and bacteria, from a gas, the device comprising means for transmitting the infectant-containing gas to a gas inlet of a housing, which housing is further provided with a gas outlet, a disinfectant liquid inlet and a disinfectant liquid outlet; a rotor mounted for rotation in said housing and connecting to the inlets and outlets, the rotor comprising a plurality of disinfecting channels extending axially and parallel to a common rotation axis, wherein the channels are circumferentially enclosed by walls over an, optionally entire, axial length of the rotor between the disinfectant liquid inlet and the disinfectant liquid outlet; and wherein the device further comprises means for rotating the rotor and means for providing a sustained flow of disinfectant liquid to the disinfectant liquid inlet, wherein the device further comprises a disinfectant liquid collector that connects to the disinfectant liquid outlet, in which collector the collected disinfected particles settle to form a disinfected particle-rich bottom layer and a disinfected particle-poor top layer; and a return conduit that connects the disinfectant liquid collector outlet with the disinfectant liquid inlet, and a pump to transfer disinfectant liquid from the disinfected particle-poor top layer to the disinfectant liquid inlet through the return conduit for re-use; wherein the return conduit, the liquid collector outlet and the disinfectant liquid inlet form a closed fluid circuit.

2. The rotational disinfectant device according to claim 1, wherein the gas inlet and the disinfectant inlet are located upstream of the rotor, and the gas outlet and the disinfectant liquid outlet are located downstream of the rotor.

3. The rotational disinfectant device according to claim 1, wherein the gas inlet and the disinfectant outlet are located downstream of the rotor, while the disinfectant inlet is located upstream of the rotor.

4. The rotational disinfectant device claim 1, wherein the gas transmitting means are located opposite to the gas inlet relative to the rotor.

5. The rotational disinfectant device according to claim 1, wherein the gas transmitting means comprise a propeller.

6. The rotational disinfectant device according to claim 1, wherein the rotor and/or the housing is made from a polymer, such as a polyolefin polymer, preferably a flame retardant polymer.

7. The rotational disinfectant device according to claim 1, further comprising a high-efficiency particulate air (HEPA) filter positioned downstream of the rotor of the rotational disinfectant device.

8. The rotational disinfectant device according to claim 7, wherein the high-efficiency particulate air (HEPA) filter is positioned downstream of the disinfectant liquid collector of the rotational disinfectant device.

9. The rotational disinfectant device according to claim 1, further comprising an outlet for the disinfected particle-rich bottom layer, optionally provided with a shut-off valve, which outlet is provided for draining the disinfected particle-rich bottom layer from the disinfectant liquid collector.

10. An assembly of a plurality of rotational disinfectant devices according to claim 1, wherein the assembly comprises a common vessel for disinfectant liquid, and the devices each connect to the common vessel for disinfectant liquid via a liquid conduct.

11. The assembly according to claim 10, wherein a pump means is provided for pumping the disinfectant liquid to each rotational disinfectant device.

12. The assembly according to claim 10, wherein each rotational disinfectant device is positioned in proximity of a source of infectant.

13. (canceled)

14. (canceled)

15. A method for capturing and disinfecting infectants, comprising viruses, such as SARS-CoV-2, and bacteria, from a gas, the method comprising the steps of providing a rotational disinfectant device in accordance with claim 1, transmitting and feeding the infectant-containing gas to a gas inlet of the housing, feeding a disinfectant liquid to the disinfectant liquid inlet, rotating the rotor in said housing which causes the disinfectant liquid to confine to an inward facing wall of the disinfecting channels and form a film thereto, allowing transport of infectant particles from the gas to the disinfectant liquid, and exiting the gas through the gas outlet and the infectant particle-containing disinfectant liquid through the disinfectant liquid outlet, wherein the disinfectant liquid is collected before exiting it through the disinfectant liquid outlet, and the collected disinfected particles are allowed to settle to form a disinfected particle-rich bottom layer and a disinfected particle-poor top layer, and wherein disinfectant liquid from the disinfected particle-poor top layer is pumped through a return conduit that connects the disinfectant liquid collector outlet with the disinfectant liquid inlet to the disinfectant liquid inlet for re-use.

16. The method according to claim 15, wherein the gas and the disinfectant liquid are fed upstream of the rotor, and the gas and the disinfectant liquid exit downstream of the rotor.

17. The method according to claim 15, wherein the gas is fed downstream of the rotor, the disinfectant liquid is fed upstream of the rotor, and the gas and disinfectant liquid exit downstream of the rotor.

18. The method according to claim 15, wherein the gas is transmitted by gas transmitting means, such as a propeller, located opposite to the gas inlet relative to the rotor.

19. The method according to claim 15, wherein the gas is led through a high-efficiency particulate air (HEPA) filter positioned downstream of the rotor of the rotational disinfectant device before exiting through the gas outlet.

20. The method according to claim 19, wherein the gas is led through a high-efficiency particulate air (HEPA) filter positioned downstream of the disinfectant liquid collector of the rotational disinfectant device before exiting through the gas outlet.

21. The method according to claim 15, wherein the disinfected particle-rich bottom layer is drained from the disinfectant liquid collector to an outlet for the disinfected particle-rich bottom layer, which outlet is optionally shut-off after draining.

22. The method according claim 15, wherein the rotation rate Ω (in rad/s) of the rotor 17 is chosen such that Ω≥Ω.sub.min wherein
Ω.sub.min=[ρ.sub.G/(μ.sub.Ld.sub.cR)].sup.1/2u.sub.G  (1) wherein Ω is the rotation rate (in rad/s) of the rotor, ρ.sub.G represents the density of the gas (in kg/m.sup.3), ρ.sub.L is the density of the disinfectant liquid (in kg/m.sup.3), d.sub.c is channel height (in m), R is the radial position of the channel in the rotor (in m), and u.sub.G is the velocity of the gas (in m/s).

23. The method according to claim 15, wherein an assembly is used.

24. The method according to claim 23, wherein the disinfectant liquid is pumped from the common vessel for disinfectant liquid to each rotational disinfectant device.

25. The method according to claim 23, wherein each rotational disinfectant device is positioned in proximity of a source of infectant particles.

26. (canceled)

27. (canceled)

28. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The above brief description, as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred, but nonetheless illustrative embodiments, when taken in conjunction with the accompanying drawings wherein:

[0058] FIG. 1A is a schematic top view of a rotating disinfectant device according to an embodiment of the present invention;

[0059] FIG. 1B is a schematic cross-sectional side view of a cross-section along a plane A-A of the embodiment shown in FIG. 1A;

[0060] FIG. 2 is a cross-sectional side view of another embodiment of the rotating disinfectant device according to the invention,

[0061] FIG. 3 is a schematic side view of an assembly of rotating disinfectant devices according to an embodiment of the invention,

[0062] FIG. 4A is a schematic top view of a rotating disinfectant device according to another embodiment of the present invention;

[0063] FIG. 4B is a schematic cross-sectional side view of a cross-section along a plane A-A of the embodiment shown in FIG. 4A;

[0064] FIG. 5A is a schematic top view of a rotating disinfectant device according to another embodiment of the present invention;

[0065] FIG. 5B is a schematic cross-sectional side view of a cross-section along a plane A-A of the embodiment shown in FIG. 5A;

[0066] FIG. 6A is a schematic top view of a rotating disinfectant device according to yet another embodiment of the present invention;

[0067] FIG. 6B is a schematic cross-sectional side view of a cross-section along a plane A-A of the embodiment shown in FIG. 6A; and

[0068] FIG. 7 schematically shows how an infectant particle is separated and disinfected in a channel of a rotational disinfectant device.

DESCRIPTION OF THE INVENTION

[0069] Referring to FIGS. 1A and 1B, a rotating disinfectant device 100 according to an embodiment of the invention is shown. The device 100 comprises a cylindrical housing 16 in which a rotor 17 is mounted on a shaft 18 supported by bearings 19. The rotor 17 consists of a large number of axially extending disinfecting channels 1, arranged parallel to a rotation axis 20.

[0070] The rotor 17 is fixed to the shaft 18 which is rotatably mounted in the bearings 19, and which can be externally driven, if desired. Possible leakage between rotor 17 and housing 16 may be prevented by a suitable sealing arrangement. The housing 16 is provided with an air inlet 2 and an air outlet 3. The air inlet 2 consists of a duct that is tangentially positioned at position 4 in the cylindrical housing 16 at an upstream end thereof to induce a swirling rotational motion of the incoming air in the housing 16. The swirling air motion induces a rotation of the rotor 17 within the housing 16 without any external driving means such as a rotational motor. The device further is provided with means for transmitting the virus-containing air from the surroundings to the air inlet 2. A preferred embodiment as shown provides a transmitting means in the form of a propeller 3a or other air suctioning means in the air outlet 3. This transmitting means is essential in being able to suck in virus-containing air into the device 100.

[0071] The air outlet configuration 3 is a mirror image of the air inlet configuration 2 and comprises a duct that is tangentially positioned at position 5 in the cylindrical housing 16 at a downstream end thereof to direct the outcoming air from a swirling rotational motion into a translating motion while leaving the housing 16 at position 5.

[0072] Apart from the tangential inlets 2 and outlets 3, rotational air motion can also be generated and nullified by stationary curved blades (not shown) provided at an upstream end and a downstream end of the rotor 17. The inner part of the static blade construction may contain the bearings 19 of the rotor 17.

[0073] On top of the housing 16 at the upstream end thereof, an inlet 6 for (fresh) disinfectant liquid 21 is provided. In the embodiment shown, the liquid 21 is sprayed on top of the rotor 17 according to arrow 23 by a suitable spraying arrangement. The liquid 21 is sprayed on top of the rotor 16 whereby a rotation of the rotor around the axis 20 provides for an even distribution of liquid 21 over the channels 1. At the downstream side of the rotor 16, the disinfectant liquid 21 that now contains disinfected virus particles (denoted as disinfected virus-containing liquid 22) leaves the facing wall of a cylindrical shell 7 that forms an axial extension of the outer boundary wall of the rotor 16. At an inner side of the cylindrical shell 7 wall, a new film of disinfected virus-containing liquid 22 forms that breaks up at an outer end of the cylindrical shell 7 wall and is propelled as droplets to a liquid collection chamber 8 in the form of a cylindrical ridge provided inside the housing 17. The disinfectant liquid leaves the housing 16 at outlet 13.

[0074] As an alternative to the vertical arrangement shown in FIGS. 1A and 1B, the rotational disinfectant device 100 according to an embodiment may be positioned horizontally. The flow of liquid 21 inside the channels 1 is controlled by centrifugal forces and shear forces exerted by the air flowing inside the channels 1 of the rotor 17. When leaving the channels 1 of the rotor 17, the motion of the disinfected virus-containing liquid 22 and liquid droplets is governed by centrifugal forces. Gravitation becomes important only when the liquid flow is brought to rest in collection tanks (not shown) provided outside the rotational disinfectant device.

[0075] An external drive or engine may be used when there is a need to rotate the rotor 17 independently of the air flow. Such means for rotating the rotor may in such an embodiment be connected to the rotor 17 through a magnetic coupling for instance. No shaft piercing through the housing 16 is needed in such embodiment, thus keeping the advantage of preventing the use of complicated sealing arrangements to prevent escape of virus-containing air.

[0076] Because of the small cross-sectional width of the channels 1, the air will exert a rather strong shear force on the liquid 21 while travelling down the rotor 17 from the upstream end to the downstream end. This may cause the liquid 21 to flow in the same (downstream) direction 24 as the air.

[0077] FIG. 7 schematically shows the principal working of separation and disinfection inside a channel 1 of the rotational disinfectant device 100. An air flow 52 of average velocity u.sub.G enters a channel 1 of the rotor 17, and exits the channel 1 again at the bottom according to the arrow 53. Rotation of the rotor 17 around the rotation axis 20 of the rotor 17 serves two purposes. Firstly, the centrifugal force F produced by the rotation may force and infectant particle 50 within a channel 1 to move to the radially inward facing wall 1a of the channel 1 according to a trajectory 51, and to arrive inside a film 21a of disinfectant liquid that is formed on the inner facing wall 1a. The disinfectant liquid 21 disinfects the particle 50. Secondly, the centrifugal force F is instrumental in keeping the disinfectant liquid film 21a attached to the inward facing wall 1a. For disinfecting purposes, it is advantageous to keep the liquid film 21a against the wall 1a. To achieve this, a minimum rotational speed Ω.sub.min below which the disinfectant liquid (21, 22) will be blown away from the wall 1a by the moving gas or air may be defined. It is known that this happens for liquid films at the bottom of planar horizontal channels whenever the gas flow becomes too strong in comparison with the gravitational force or gravitational acceleration ‘g’. That is, when the gas velocity u.sub.G is larger than [g.Math.(μ.sub.L/ρ.sub.G).Math.d.sub.c].sup.1/2 the liquid film is blown away from the bottom.

[0078] In the rotational disinfectant device 100, the centrifugal acceleration Ω.sup.2 R is preferably designed to be much larger than the gravitational acceleration and sufficiently large to keep the liquid film 21a firmly attached to the wall 1a. To ensure attachment of the liquid film 21a to the inner facing wall 1a and provide an optimum disinfection, the rotation rate Ω (in rad/s) of the rotor 17 is preferably selected such that Ω≥Ω.sub.min wherein:

Ω.sub.min=[ρ.sub.G/(ρ.sub.Ld.sub.cR)].sup.1/2u.sub.G  (1) [0079] wherein Ω is the rotation rate (radians per sec) of the rotor, ρ.sub.G represents the density of the air (gas) (in kg/m.sup.3), ρ.sub.L is the density of the disinfectant liquid (in kg/m.sup.3), d.sub.c is channel height (in m), R is the radial position of the channel in the rotor (in m), and u.sub.G is the velocity of the gas (in m/s). The expression tells that a higher gas velocity (a higher capacity or gas intake of the system) also preferably requires a higher rotation rate Ω. Also, the channels 1 positioned at the smallest radial location R are most vulnerable to separation of the liquid film 21a from the wall 1a. The gas velocity is determined by the gas flow 4G (in m.sup.3/s) through the entire rotor 17, the number ‘n’ of channels 1 in the rotor 17 and the cross-sectional area A.sub.c (in m.sup.2) of the channels, as follows:

Ω.sub.min=[ρ.sub.G/(ρ.sub.Ld.sub.cR)].sup.1/2u.sub.G  (2)

[0080] To improve the efficiency of the disinfecting operation, and referring to FIG. 2, an embodiment of the rotational disinfectant device 100 may comprise a first disinfectant liquid inlet 6 for disinfectant liquid 21a, and a second disinfectant liquid inlet 14 for disinfectant liquid 21b, located upstream of a first rotor 17a and a second rotor 17b respectively, both provided on a common shaft 18. A first disinfectant liquid outlet 13 is provided at a downstream end of the first rotor 17a, whereas a second disinfectant liquid outlet 15 is provided downstream of the second rotor 17b, which outlet 15 reconnects to the first inlet 6. The air enters the device 100 tangentially at the top of the device 100 at inlet 9, and leaves the device 100 at the bottom through outlet 10. The rotating rotors 17a and 17b have been mounted on a common shaft 18 at a top end 11 and a bottom end 12. The rotors 17a and 17b are kept at an axial distance from each other to enable the provision of outlets 13 for removing liquid exiting from the first rotor 17a, and to inject fresh liquid 21b trough inlets 14 to an upstream end of the second rotor 17b. The air exiting the first rotor 17a enters the second rotor 17b, while fresh disinfectant liquid 21b is fed through inlet 14 to the second rotor 17b. When leaving the second rotor 17b, the partly used disinfectant liquid is returned to the first rotor 17a and leaves this rotor 17a as more completely or even fully utilized disinfectant liquid 22b.

[0081] The amount of rotors mounted in series on an optionally common shaft may be extended to more than two in order to approximate the configuration of countercurrent absorption in more detail. It is possible therefore to adopt a rotational disinfectant device that comprises at least two rotors in series, more preferably at least three rotors in series, and even more preferably at least five rotors in series.

[0082] Referring to FIGS. 4A and 4B, a rotating disinfectant device 100 according to yet another embodiment of the invention is shown. The device 100 is similar to the embodiment shown in FIGS. 1A and 1B except for two differences. First, the housing 16 is provided with an air inlet 2 that consists of a duct, tangentially positioned at position 4 in the cylindrical housing 16 at a downstream end thereof to induce a swirling rotational motion of the incoming air in the housing 16. The air outlet configuration 3 is a mirror image of the air inlet configuration 2 and comprises a duct that is tangentially positioned at position 5 in the cylindrical housing 16 at an upstream end thereof to direct the outcoming air from a swirling rotational motion into a translating motion while leaving the housing 16 at position 5. A transmitting means in the form of a propeller 3a or other air suctioning means is provided in the outlet 3.

[0083] As with the embodiment of FIGS. 1A and 1B, an inlet 6 for (fresh) disinfectant liquid 21 is provided on top of the housing 16 at the upstream end thereof. At the downstream side of the rotor 16, the disinfectant liquid 21 that now contains virus particles (denoted as virus-containing liquid 22) leaves the facing wall of a cylindrical shell 7 that forms an axial extension of the outer boundary wall of the rotor 16. At an inner side of the cylindrical shell 7 wall, a new film of virus-containing liquid 22 forms that breaks up at an outer end of the cylindrical shell 7 wall and is propelled as droplets to a liquid collection chamber 8 in the form of a cylindrical ridge provided inside the housing 17. The disinfectant liquid leaves the housing 16 at outlet 13.

[0084] The embodiment of FIGS. 4A and 4B allows a counter-current operation of the disinfecting device by injecting disinfectant liquid at the top (upstream end) of the device which flows downward while air which is injected at the bottom (downstream end) of the device flows upward. The propeller or fan 3 provides a pressure difference to assist the air flow through the channels. Cleaned air leaves the rotating element at the top and liquid loaded with killed virus particles leaves at the bottom.

[0085] A second difference between the embodiment of FIGS. 1A and 1B, and that of FIGS. 4A and 4B is that the latter comprises a return conduit 27 for overflow of disinfectant liquid. The return conduit 27 connects to the housing 16 at an upward end of the rotor 17 and to the inlet 6 provided on top of the housing 16 at the upstream end thereof. Overflowing disinfectant liquid is returned to the inlet 6 through the conduit 27.

[0086] Overflow of disinfectant liquid may occur when operating the device in counter-current flow and turbulent conditions, as explained below. Turbulent air flow in the channels will prevail when the Reynolds number is sufficiently large. For practically realistic values of flow velocity and channel diameter, a pressure in the channels of 2, 3, 4 and up to 5 bar may be needed to have a sufficiently large value of the air density to end up with turbulent flow. At increased pressure and density combined with turbulent flow, the shear force acting by the upward streaming air on the liquid film formed in the channels will be large to the extent that air and liquid flow may flow in the same direction, i.e. both upwards. Even when the channels are oriented in a vertical direction, the force of gravity acting on the disinfectant liquid in the channels may not be large enough to result in a downward flow of disinfectant liquid opposite to the upward flow of air. Counter-current flow in the channels may even be impossible in certain cases. On the other hand, at more moderate pressures of below 5 bar for instance, more preferably below 4, bar, even more preferably below 3 bar and most preferably below 2 bar, the upward air flow is prevailingly laminar and the shear force exerted by the upward streaming air on the disinfectant liquid film in the channels may no longer exceed the force of gravity.

[0087] Another embodiment in shown in FIGS. 5A and 5B. This embodiment is similar to the embodiment shown in FIGS. 1A and 1B. However, the embodiment makes use of the fact that in the collector 8, the collected disinfected particles settle to form a disinfected particle-rich bottom layer and a disinfected particle-poor top layer. The embodiment further comprises a return conduit 33 that connects the disinfectant liquid collector outlet 13 with the disinfectant liquid inlet 6, and a pump 34 to transfer disinfectant liquid from the disinfected particle-poor top layer to the disinfectant liquid inlet 6 for re-use.

[0088] The rotational disinfectant device according to another embodiment may also comprise an outlet 35 for the disinfected particle-rich bottom layer, optionally provided with a shut-off valve 36. The outlet 35 is provided for draining the disinfected particle-rich bottom layer from the disinfectant liquid collector 8, if needed.

[0089] Yet another embodiment in shown in FIGS. 6A and 6B. This embodiment is similar to the embodiment shown in FIGS. 4A and 4B. However, the embodiment makes use of the fact that in the collector 8, the collected disinfected particles settle to form a disinfected particle-rich bottom layer and a disinfected particle-poor top layer. The embodiment further comprises a return conduit 33 that connects the disinfectant liquid collector outlet 13 with the disinfectant liquid inlet 6, and a pump 34 to transfer disinfectant liquid from the disinfected particle-poor top layer to the disinfectant liquid inlet 6 for re-use. This embodiment may also comprise an outlet 35 for the disinfected particle-rich bottom layer, optionally provided with a shut-off valve 36, as disclosed above.

[0090] As shown in FIG. 3, the rotational disinfectant device 100 is particularly useful when used as an assembly of a plurality of such rotational disinfectant devices 100. The assembly comprises a common vessel 60 for distributing disinfectant liquid 21 to each device 100. To this end, the devices 100 each connect to the common vessel 60 for disinfectant liquid 21 via a liquid conduct 61. In the same manner, the assembly comprises a common storage 62 for killed virus-containing disinfectant liquid for collecting virus-containing disinfectant liquid 22 from each device 100. To this end, the devices 100 each connect to the common storage 62 for killed virus-containing disinfectant liquid 22 via a liquid conduct 63. The assembly comprises a pump means (not shown) for pumping the disinfectant liquid (21, 22) to and from each rotational disinfectant device 100.

[0091] Each rotational disinfectant device 100 is positioned in proximity of a source of virus particles. In the example of FIG. 3, the devices 100 are provided in a bus carriage. The indoor space 65 of the bus is provided with a plurality of seats 64, wherein each seat 64 is associated with a rotational disinfectant device 100, as shown in front of each seat 64. The exact position of each device 100 may be different. They may for instance be provided in the front seat back, or under each seat 64. Emitted virus particles are in such an embodiment effectively collected from the air and transmitted and fed to the channels of each rotational disinfectant device, in which channels the virus is killed by contacting it with the disinfectant liquid, in a relatively short time. Alternatively, the virus and bacteria infected air or gas may be withdrawn in close proximity (for instance within a distance of 2 m, preferably 1.5 m, more preferably 1 m) of the source by multiple exhaustion points. The infected air or gas is subsequently transported through tubes, joined and disinfected by a central single rotational disinfecting device, according to an embodiment of the invention.