AIRBORNE MICROORGANISMS NEUTRALIZING SYSTEM AND METHOD OF NEUTRALIZING AIRBONE MICROORGANISM

Abstract

A system for neutralizing airborne microorganisms includes a conditioning section for accommodating a flow of air, the conditioning section including an air inlet; an air outlet; a packing chamber located downstream relative to the air inlet, a distribution chamber located downstream relative to the packing chamber and located above the packing chamber, the distribution chamber including at least one spray nozzle for spraying a liquid desiccant into the distribution chamber towards the packing chamber; a sump located below the packing chamber; a pump for propelling the liquid desiccant from the sump to the at least one spray nozzle; a droplet collection chamber located downstream relative to the at least one spray nozzle for removing droplets from the flow of air flowing through the droplet collection chamber; and a UV disinfection chamber located downstream relative to the droplet collection chamber and upstream relative to the air outlet.

Claims

1. A system for neutralizing airborne microorganisms, comprising: a conditioning section for accommodating a flow of air, the conditioning section comprising: an air inlet for receiving microorganism laden air; an air outlet for delivering microorganism free air; a packing chamber located downstream relative to the air inlet, the packing chamber being filled with a fibrous packing material; a distribution chamber located downstream relative to the packing chamber and located above the packing chamber when the system is in a normal position of use, the distribution chamber including at least one spray nozzle for spraying a liquid desiccant into the distribution chamber towards the packing chamber; a sump located below the packing chamber when the system is in the normal position of use for receiving the liquid desiccant that has penetrated the packing chamber from the distribution chamber through gravity; a pump for propelling the liquid desiccant from the sump to the at least one spray nozzle; a droplet collection chamber located downstream relative to the at least one spray nozzle for removing droplets from the flow of air flowing through the droplet collection chamber; and a UV disinfection chamber located downstream relative to the droplet collection chamber and upstream relative to the air outlet, the UV disinfection chamber comprising a UV energy source for exposing the flow of air to UV irradiation.

2. The system according to claim 1, wherein the liquid desiccant comprises a mixture of water and a salt, the salt being CaCl.sub.2 or LiCl, and the concentration of the salt in the mixture being between 10% and 60%.

3. The system according to claim 2, wherein the concentration of the salt in the mixture is between 20% and 45%.

4. The system according to claim 1, wherein the UV energy source is an LED or a low-pressure UV lamp.

5. The system according to claim 4, wherein the low-pressure UV lamp is a low-pressure mercury lamp.

6. The system according to claim 1, wherein an intensity of UVC energy inside the UV disinfection chamber is at least 10 W/m.sup.2.

7. The system according to claim 1, wherein an intensity of UVC energy inside the UV disinfection chamber is at least 50 W/m.sup.2.

8. The system according to claim 1, wherein an intensity of UVC energy inside the UV disinfection chamber is at least 124 W/m.sup.2.

9. The system according to claim 1, wherein the conditioner and/or internal parts are constructed of non-metallic plastics.

10. The system according to claim 1, wherein the droplet collection chamber includes a replaceable pad demister.

11. The system according to claim 1, further comprising a blower for generating the flow of air from the air inlet to the air outlet.

12. The system according to claim 11, wherein the flow of air defines a velocity less than 3 m/s.

13. The system according to claim 11, wherein the flow of air defines a velocity less than 2.235 m/s.

14. The system according to claim 1, wherein the system comprises a heat exchanger between the sump and the at least one spray nozzle for cooling the liquid desiccant.

15. The system according claim 1, wherein the exposure to UV irradiation occurs within a moving airstream downstream from the droplet collection chamber.

16. The system according to claim 1, wherein the UV disinfection chamber comprises UVC energy of 124 W/m.sup.2 at air flow and a velocity less than 3 m/s for microbial inactivation.

17. The system according to claim 1, wherein the UV disinfection chamber comprise an array of UV energy sources.

18. The system according to claim 1, further comprising a regenerating section for regenerating the liquid desiccant.

19. The system according to claim 18, wherein the regenerating section extends between a secondary air inlet for dry air and a secondary air outlet for humid air and defines a secondary flow direction, the regenerating section comprising: a secondary packing chamber located downstream relative to the air secondary inlet, the secondary packing chamber being filled with a secondary high efficiency packing material; a secondary spray chamber located downstream relative to the secondary packing chamber and located above the secondary packing chamber when the system is in the normal position of use, the secondary spray chamber including at least one secondary spray nozzle for spraying the liquid desiccant into the secondary spray chamber towards the secondary packing section; a secondary sump located below the secondary packing chamber when the system is in the normal position of use for receiving the liquid desiccant from the secondary spray chamber that has penetrated the secondary packing chamber through gravity; a secondary pump for pumping the liquid desiccant from the secondary sump to the at least one secondary spray nozzle; and a secondary heat exchanger between the secondary sump and the at least one secondary spray nozzle for heating the liquid desiccant.

20. A method of neutralizing airborne microorganisms comprising: providing a conditioning section comprising: an air inlet; an air outlet; a packing chamber located downstream relative to the air inlet, the packing chamber being filled with a fibrous packing material; a distribution chamber located downstream relative to the packing chamber and located above the packing chamber when the system is in a normal position of use, the distribution chamber including at least one spray nozzle; a sump located below the packing chamber when the system is in the normal position of use; a pump; a droplet collection chamber located downstream relative to the spray nozzle; and an UV disinfection chamber located downstream relative to the droplet collection chamber and upstream relative to the air outlet, wherein the method comprises the steps of: introducing microorganism laden air into the air inlet; spraying a liquid desiccant into the distribution chamber towards the packing section by using an engineered spray system; receiving the liquid desiccant that has penetrated the packing chamber from the distribution chamber through gravity into the sump, propelling the liquid desiccant from the sump to the at least one spray nozzle; removing droplets from the air flowing through the droplet collection chamber; exposing the air within the UV disinfection chamber to UV irradiation; and receiving microorganism free air at the air outlet.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0057] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

[0058] The FIGURE shows a system for neutralizing airborne micororganims including a conditioning section and a regenerating section.

DETAILED DESCRIPTION OF THE DRAWING

[0059] The FIGURE shows a system 10 for neutralizing airborne micororganims. The system comprises separate conditioning and regenerating sections 12, 12. The conditioning section 12 comprises an air inlet 14 for receiving air from the outside. A blower 40 can be provided for generating a flow of air from the air inlet to the air outlet. The blower 40 may also be an integral part of the ventilation system in which the system 10 for neutralizing airborne microorganisms is installed. The outside air and/or return air may include harmful microorganisms contained in aerosols which may be introduced into the indoor air. In sensitive environments, such as the food/beverage industry and healthcare facilities/industry, these microorganisms may cause disease. Microorganims may include: Pseudomonas aeruginosa, Klebsiella, Acinetobacter, Staphylococcus aureus, Clostridium difficile, E. coli, Listeria and Salmonella.

[0060] The conditioning section 12 incorporates industrial-grade fiberglass construction with internal parts of non-metallic engineered plastics. The flow of air from the air inlet 14 is drawn through a sump area 16 with a 180 turn as shown by the arrow. The sump area 16 comprising a solution of liquid desiccant. The liquid desiccant within the system is preferably an aqueous solution of LiCl or CaCl.sub.2 and can be adjusted to various concentration levels (20% to 45%) to accommodate the required temperature and humidity level for the corresponding conditioned space. The flow then continues into a high efficiency contact fibrous packing chamber 18 impregnated with liquid desiccant that allows for maximum surface contact of air to liquid desiccant.

[0061] Downstream relative to the packing chamber 18 and above the packing chamber 18 when the conditioning section is in its normal position of use, a distribution chamber 20 is located. The distribution chamber 20 includes a liquid desiccant spray distribution header 22. The spray distribution header includes one or more spray nozzles 22a-e for spraying solution into the distribution chamber 20 towards the packing chamber 18 and generating an aerosol of liquid desiccant in the distribution chamber 20. The spray nozzles 22a-e are capable of flooding the distribution chamber 20 with liquid desiccant at a specific particle size and distribution. The distribution header 22 is equipped with flow regulation.

[0062] Downstream relative to the distribution chamber 20 and above the distribution chamber 20 when the conditioning section is in its normal position of use, a droplet collection chamber 24 is located. The droplet collection chamber 24 comprises an engineered mist eliminator located directly downstream of the distribution chamber 20. In the droplet collection chamber 24, any droplets in the flow of air are removed. The droplet collection chamber 24 in the present example includes a Z-bar 24a and a demister pad 24b. Alternatively, the Z-bar 24a may be omitted and a thicker demister pad 24b may be used instead.

[0063] The air subsequently enters a UV disinfection chamber 26 having adequate UV energy for irradiating the flow of air. The treated air is released through the air outlet 30. The combined effect of the solution treatment and the UV treatment achieves a minimum 99.999% reduction of microorganisms. The UV irradiation in the present example is carried out by the use of an array of UV lamps 28a-c.

[0064] The liquid desiccant is propelled from the sump 16 to the distribution header 22 by a pump 32. The conditioning section 12 also incorporates liquid desiccant cooling via an externally mounted heat exchanger 34 located inbetween the pump 32 and the distribution header 22. The heat exchanger 34 controls temperature (2) and humidity (1%) within the conditioned environment of the conditioning section 12. The humidity level is controlled via the temperature, as well as the concentration of the desiccant being sprayed from the spray nozzles 22a-e.

[0065] As the liquid desiccant absorbs water from the air, its ability to absorb more water, diminishes. Therefore, the system 10 also includes a regenerating section 12 for regenerating the water absorbing properties of the desiccant solution. The regenerating section 12 is similar to the conditioning section 12 and incorporates industrial-grade fiberglass construction with internal parts of non-metallic engineered plastics.

[0066] It should be noted that regeneration is not required to maintain the anti-bacterial properties of the solution. However, to maintain the dehumidifying properties of the solution, the solution must be pumped through a regenerator. In the present example, the solution is propelled from the sump 16 of the conditioning section 12 to the regenerating section 12. In the present embodiment, a part of the flow which is propelled from the sump 16 to the distribution header 22 is redirected to the regenerating section 12. A valve 36 is used for controlling the flow of solution from the conditioning section 12 to the regenerating section 12. The regenerated liquid desiccant from the sump 16 of the regenerating section 12 is returned to the conditioning section 12 in a similar fashion controlled by a valve 36. A heat exchanger 38 is used to equalise the temperature between the opposite flows of solution between the the conditioning section 12 and the regenerating section 12.

[0067] In the regenerating section 12, a separate flow of air is received from an air inlet 14 and is drawn through a sump area 16 with a 180 turn as shown by the arrow. A blower 40 can be provided for generating the flow of air from the air inlet 14 to an air outlet 30. The sump area 16 comprising the liquid desiccant. The flow then continues into a high efficiency contact packing chamber 18 impregnated with liquid desiccant that allows for maximum surface contact of air to liquid desiccant. Downstream relative to the packing chamber 18 and above the packing chamber 18 when the regenerating section is in its normal position of use, a distribution chamber 20 is located. The distribution chamber 20 includes a solution spray distribution header 22.The spray distribution header includes a drip tray or one or more spray nozzles 22a-e for spraying liquid desiccant into the distribution chamber 20 towards the packing chamber 18.

[0068] Downstream relative to the distribution chamber 20 and above the distribution chamber 20 when the regenerating section 12 is in its normal position of use, a droplet collection chamber 24 is located. Solution is propelled from the sump 16 to the distribution header 22 by a pump 32. The regenerating section 12 also incorporates solution heating via a heat exchanger 34 located inbetween the pump 32 and the distribution header 22. Heating the liquid desiccant will allow it to release water to the flow of air, which is released outdoor via an air outlet 30.

[0069] The system 10 incorporates an electric and PLC (Programmable Logic Controller) control panel, fused disconnect, motor starters and level sensors. The PLC control panel incorporates a colour touch screen programmed with relay logic, diagnostic and loop control functions. A diagram of the dehumidification system is displayed on the screen indicating the status of the conditioning section fan, pump and outlet temperature; the regenerating section fan, pump, solution level and set points are also displayed. The conditioning section 12 incorporates temperature and pressure gauges with flanged connections. The regenerating section 12 incorporates a control valve with electric operator for either steam or hot water; temperature and pressure gauges with flanged connections are also incorporated. Solution transfer modulating control valves with hand isolation are incorporated into both the conditioning and regenerating sections. A water makeup on/off control valve is also incorporated.

[0070] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.