This disclosure relates generally to germ elimination technology.
The disinfection properties of ultraviolet (UV) radiation in the 200-300 nm have been documented. Many solutions using UV radiation, such as cavity disinfection and whole room decontamination between uses, are in use in various industries (e.g., healthcare).
The elimination of an organism via UV radiation is generally dose-dependent. There have been investigations into the optimal dose required, showing a generally large range of efficacious dosages administered. For example, it has been shown that 222 nm UV radiation is able to inactivate various coronaviruses to the 3-log level with a dose of approximately less than or equal to 2 mJ/cm2. It has also been shown that the H1N1 virus requires a dose of 4 mJ/cm2 to give a 4-log (99.99%) reduction using 222 nm radiation. Further, it has been shown that irradiation by 254 nm UV provided similar elimination of H1N1. For the Murine Hepatitis Virus coronavirus, a similar dose requirement was found when irradiated with 254 nm UV. 254 nm and 222 nm radiation generally gives similar results for bacterial targets, even though the precise cause of elimination is considered different.
While the elimination of organisms via UV radiation is known, it can be difficult to create UV devices that eliminate or reduce organisms in an economical and efficient manner That is, it can be difficult to economically produce a device that provides the amount of UV energy per unit of area needed to achieve the desired pathogen reductions. For example, in order to produce the desired UV energy per unit of area, devices often employ multiple UV lights. As the amount of UV lights in such devices increase, the costs of such devices can also increase. In turn, the maintenance costs of such devices can also increase if, and how often, the UV lights fail during the device life-span.
Accordingly, there is a need for efficient and economical UV disinfectant devices or machines.
Devices or machines that can safely, efficiently, economically, and continuously disinfect inhaled and/or exhaled air using ultraviolet (UV) radiation with possible pathogen elimination up to 99.99% or more are set forth. As will be discussed in further detail below, such devices or machines may, for example, be configured as personal (e.g., wearable) units or units to “clean” enclosure air (e.g., building rooms, underground bunkers, transportation vehicles, and etc.). The utilized UV radiation may be in the 260 nm range where no ozone is produced, thus minimizing manufacturing costs since mechanical and/or chemical ozone mitigation measures can be avoided. These devices may be portable, wearable, or scaled up to larger sizes as needed. Further, since a utilized UV chamber (see. e.g.,
The manner in which the chambers or cavities of such devices are designed provide an amplification of irradiated UV power by approximately 10-50 times. That is, the irradiated UV power may be amplified by approximately 10-50 times due to the innovative design of the cavities set forth below.
As will be discussed in detail below, in some examples, such devices may be employed as a Personal Ultraviolet Respiratory Germ Eliminating Machine (PUR GEM) or device, which may be worn by a user or attached to devices such as a ventilator exhaust and/or ventilator intake. In other examples, such devices may serve as free-standing portable (or permanent) air disinfection units.
Referring now to
The first and second cavities 106, 108 are spheroid, though the chambers 102, 104 need not be spheroid. That is, though not shown, the first and second chambers 102, 104 may be a shape different than spheroid while the cavities 106, 108 therein remain spheroid. Further, these chambers 102, 104 may be permanently coupled to each other or, alternatively, be modular such that they may be separated as needed or that additional chambers with cavities (not shown) may be added.
In yet another example, the GEM 100 may instead include a single chamber 110 (shown in phantom), that includes the first and second spheroid cavities 106, 108. That is, instead of two chambers 102, 104 each including the respective spheroid cavity 106, 108, the single chamber 110 may instead be configured to include the first and second spheroid cavities 106, 108. While
With reference back to the first and second chambers 102, 104 illustrated in
A variety of UV devices may be employed. For example, mercury based cold cathode lamps (CCL) may be employed or UV light emitting diodes (LED) may be employed. While mercury CCLs are currently and generally considered cheaper than UV LEDs, UV LEDs may have advantages due to their generally longer lifespan and their ability to produce UV wavelengths more efficient for pathogen elimination.
With continued reference to
The UV reflective boundaries 116, 118 may be comprised of a variety of UV reflective materials. For example, polytetrafluoroethylene (PTFE), which is UV resistant and has a reflectance often greater than 95%, may be employed as the first and second UV reflective boundaries 116, 118. Different UV reflective materials, however, may instead be employed. Further, the materials (116, 118) need not necessarily be different than the material that comprises the chambers 102, 104. In other words, each chamber may be comprised or composed of a UV reflective material. In such an instance, a separate boundary material need not be employed since the chamber boundary itself may be adequately UV reflective.
Air 120 (e.g., outside air or patient air) passes through a first air pipe 122 to enter the first spheroid cavity 106 and a second air pipe 124 allows air from the first spheroid cavity 106 to enter the second spheroid cavity 108. A third air pipe 126 allows air to exit the second spheroid cavity 108. Accordingly, air enters the first spheroid cavity 106 where it is irradiated by the first UV device 112. Due to the reflective nature of the first reflective boundary 116 and the shape of the first spheroid cavity 106, air within the first spheroid cavity 106 is repeatedly irradiated via the first UV device 112 to increase germ elimination as it passes through the first spheroid cavity 106.
The innovative design employing the reflective boundary 116 and the spheroid-shaped cavity 106 serves as an enhancement factor for the UV device 112. In other words, for a given UV device having a power P, the spheroid cavity 106 and reflective boundary 116 can increase the power P of UV device by approximately 10-50 times, thus amplifying its ability to eliminate germs.
Air within the first spheroid cavity 106 eventually passes through the second air pipe 124 into the second spheroid cavity 108 where it is once again repeatedly irradiated by UV light, but from the second UV device 114. As such, air 120 that enters the GEM 100 is repeatedly irradiated first as it passes through the first spheroid cavity 106 and again as it passes through the second spheroid cavity 108, thus maximizing germ elimination before the air passes out the third air pipe 126. Germs may include, for example, viruses, bacteria, and/or other infectious agents.
The air pipes 122-126 may be positioned to optimize diffuse turbulent air flow through the cavities 106, 108, thus increasing the probable amount of time any given packet or unit of air is exposed to UV light (direct and reflected). For example, as illustrated in
In addition to the positions of the air pipes 122-126, the configurations of the air pipes 122-126 may also be manipulated to optimize diffuse turbulent air flow through the cavities 106, 108. For example, to further optimize diffuse turbulent air flow, each pipe 122-126 may be twisted or curved to minimize the probability of straight-line paths between consecutive air pipes (e.g., 122, 124, or 124, 126) and/or to increase the probable turbulent nature of airflow through each spheroid cavity 106, 108. That is, a bent outlet 130 of the first air pipe 122 may direct air to the first cavity UV reflective boundary material (or chamber wall) 116 to increase the turbulent nature of airflow through the cavity 106. Similarly, a bent outlet 132 of the second air pipe 124 may direct air to the second UV reflective boundary 118 (or chamber wall) to increase the turbulence in the second cavity 108. The twisted nature of the pipes 122-126 increases the diffuse and turbulent nature of air flow through each cavity 106, 108. Accordingly, the chances that a given unit of air will take a straight-line path through each cavity 106, 108 is minimized. In turn, the probable amount of time a given unit of air spends in each cavity is maximized or increased, thus increasing the probable amount of time the given unit of air, and germs contained therein, is bombarded by the direct and reflected UV light.
Inlets of the air pipes 122-126 may also be configured to maximize the turbulent nature of air flow through the cavities 106, 108 as well as to minimize straight-line air flow through the cavities 106, 108. For example, a bent inlet 134 of the second air pipe 124 may be configured to draw air from a portion of the UV reflective boundary 116 adjacent to the second air pipe 124. Similarly, a bent inlet 136 of the third air pipe 126 may be configured to draw air from a portion of the UV reflective boundary 118 adjacent to the third air pipe 126.
While the air pipes 122-126 illustrated in
With continued reference to
Referring now to
With reference back to
While
With reference now to
The GEM 300 may be multi-use. That is, the GEM 300 may be employed as a PUR GEM (see, e.g., GEM technology 200 of
While healthcare industry examples are set forth herein, the GEM (e.g., GEM 100, 300 or GEM 200) technology may be employed in other industries where “air cleaning” is desired. For example, a GEM may be employed to clean or disinfect a wide variety of enclosure air. With regard to the transportation industry, a GEM may, for example, be employed to clean cabin or interior air in aircraft, trains (e.g., a train car), buses, submarines, and/or automobiles. Further, a GEM may be employed to clean other enclosure air such as air in a building. For example, the GEM may be employed to clean or disinfect air in hospital rooms, hotel rooms, and one or more rooms in a home or underground bunker. In such instances, a GEM may be portably or “permanently” incorporated into the application. Due to the configuration of GEM technology, device size can be minimized so that it may be employed in industries constrained by space requirements.
Referring now to
One or more of the fans or the like, fan 416 and/or fan 418, may include a tight-weave cloth filter (not shown) covering an opening to and/or from the chamber to serve primarily as a particulate filter. More sophisticated particulate filters may be used if desired. A sensor 420 could be incorporated into circuit design to alert a user if air flow falls below a predetermined level. Further, the same or different sensor could be employed to alert a user or technician of low battery failures, LED device defects, and/or other mechanical or electrical issues that may arise.
Due to the reflectance and shape of the walls 412, a geometric enhancement factor for the UV power in each sphere is produced. This enhancement factor is reduced by defects in the reflecting surface, such as those due to the surface area occupied by the LED 410 and the air vents 414. Therefore, the effective reflectance Reff of the cavity (e.g., cavities 402-K) is given by:
where R is the reflectance of the walls, SAs=4πr2 is the surface area of a sphere of radius r, and Adef is the total area of defects. Practically, it may be desired to limit Adef to be less than approximately 5% of SAs. The enhancement due to effectively infinite reflections of light inside the spheroid cavity gives a multiplicative factor to PUV:
A quantity Do may then be computed as follows:
where PUV is the UV source radiation in mW, Vs=(4/3)πr3 is the volume of a sphere, and VAF is the required air flow rate in cm3/s. This quantity Do is what would be naively computed as the dose received by air flowing through a cavity (e.g., spheroid cavities 402-K) in units of mJ/cm2.
The spherical shape for the UV disinfection cavity 402-K provides excellent spatial integration. Since there are minimal radiation hot or cold spots, the UV dose received by an in-passing air volume becomes effectively independent of path taken through the sphere. However, travel time distributions, not average time, should be taken into account to accurately predict actual disinfection, and in general will reduce the actual pathogen elimination significantly independent of geometry. To compensate for this effect, a series of spheres (402-K) that effectively integrate the air paths temporally is employed, allowing for the achievement of much higher levels of actual disinfection. That is, as shown, while a single spheroid cavity may not effectively integrate air paths temporally, multiple spheroid cavities allow for the effective integration of germ paths temporally.
The time air spends in the spherical cavities 402-K will likely follow an exponential distribution due to its turbulent motion, as has been verified both numerically and experimentally. The probability that a differential volume element of air will spend a time (t) as it flows through a sphere (cavity 402-K) is given by:
where =Vs/VAF. The expectation value for pathogen elimination in this volume of air is computed by weighting it by this distribution. A convention of defining pathogen elimination in base 10 means one should convert:
where D90 is a dose required for 1−log (90%) pathogen elimination in mJ/cm2, D is dose received also in mJ/cm2, and is surviving fraction of pathogen. However, D should be computed using the time that the pathogen actually spends being irradiated. Therefore, the expectation value of a fraction of pathogen particles surviving passage through a sphere is given by
Given the series of k identical spheres, each of radius r, irradiated by PUV, pathogen elimination will be given by
k=1−0k. (2.7)
With reference now to
An exemplary personal germ eliminating machine (PUR GEM) or device (e.g.,
Nonetheless, 40 mW UV LEDs were used with an airflow of approximately 30 L/min. This leads to the following SARS-COV2 elimination:
Significantly smaller spheres may be manufactured commercially. For example, spheres with a radius of r=2 cm (i.e., similar to ping-pong ball size) may be manufactured. Using the same air flow rate as the exemplary PUR GEM, but higher power LEDs, a series of two spheres with r=2 cm would give similar disinfection as the example set forth above, thus illustrating the efficient nature of GEM technology. That is, a 2-sphere GEM, where each sphere has a radius of r/x cm and LEDS having a power of P can achieve similar disinfection as a 2-sphere GEM, where each sphere has a radius r=5 cm and LEDS of power P/x. For example,
For higher disinfection, five spheres having LEDs of the same power and radius as in equation (2.9) would provide the following pathogen (e.g., SARS-COV2) elimination:
Referring now to
While not shown, however, the technique may also include: (i) providing a first location where a first UV device passes UV light into the first spheroid cavity and (ii) providing a second location where a second UV device passes UV light into the second spheroid cavity, where the UV light reflecting in the first spheroid cavity and UV light reflecting in the second spheroid cavity damages germs in the air passing therethrough. The UV device locations may be provided prior to coupling the spheroid cavities together.
Still further, the technique may include: (i) providing an air outlet in the first spheroid cavity to direct incoming air to a boundary of the first spheroid cavity adjacent to the air outlet in the first spheroid cavity and (ii) providing an air outlet in the second spheroid cavity to direct incoming air to a boundary of the second spheroid cavity adjacent to the air outlet in the second spheroid cavity. An air intake in the first spheroid cavity may draw air from a boundary of the first spheroid cavity adjacent to the air intake in the first spheroid cavity, while an air intake in the second spheroid cavity may draw air from a boundary of the second spheroid cavity adjacent to the air intake in the second spheroid cavity. The air passing through the GEM passes out the air outlet of the first spheroid cavity through the first spheroid cavity to the air intake in the first spheroid cavity and then out the air outlet in the second spheroid cavity and through the second spheroid cavity to the air intake in the second spheroid cavity before passing out the second spheroid cavity.
The technique may also include creating additional spheroid cavities in series such as creating a third spheroid cavity having a third UV reflective boundary and creating a fourth spheroid cavity having a fourth UV reflective boundary. By coupling the third spheroid cavity to the fourth spheroid cavity, air passing into the third spheroid cavity passes through the third spheroid cavity and then through the fourth spheroid cavity.
With regard to
Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description or Abstract below, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.
When introducing elements of various embodiments of the disclosed materials, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Furthermore, any numerical examples in the following discussion are intended to be non-limiting, and thus additional numerical values, ranges, and percentages are within the scope of the disclosed embodiments.
This application claims priority to U.S. Provisional Patent Application No. 63/112,825 filed on Nov. 12, 2020, the contents of which are hereby incorporated in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/057940 | 11/3/2021 | WO |
Number | Date | Country | |
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63112825 | Nov 2020 | US |