PERSONAL AND MOBILE DEVICES FOR PROVIDING BIOLOGICAL PROTECTION BY THE ULTRAVIOLET IRRADIATION OF RECIRCULATED AIR

Abstract

The invention can be used to produce personal protection systems of respiratory organs (RPE) and organs of vision from airborne and aerosol pathogens. Additionally, it can be used to create mobile low-power closed-type recirculation systems of UV cleaning and air disinfection in small rooms and volumes: salons and cabins of various vehicles, offices, classrooms, medical rooms, etc. According to the claimed characteristics, the invention provides a high level of bactericidal treatment of air flows, including human breathing, by irradiating the flow with UV radiation from UVC-LED source with the formation of multiple times amplified luminous flux in the multi-pass irradiation chamber. The technical result is expressed in a multiple increase in the bactericidal efficacy of the device compared to devices without such a chamber, as well as in the same reduction in the requirements for the radiation power of the primary radiators according to the required bactericidal efficacy of the device.

Claims

1. The Device for inactivating pathogenic microorganisms in the air flow, made in the form of a flow-through chamber having an internal volume and at least one wall limiting such internal volume. At least one LED of the ultraviolet radiation spectrum is located in the internal volume of the chamber, while the entire internal surface of at least one specified wall is coated or made of a material reflecting ultraviolet radiation to form a multi-pass optical system. At least two through-slits or holes are made in at least one specified wall, one of which is essentially an inlet, the second is an outlet from the condition of air flow through the inner volume of the chamber.

2. The Device of claim 1, additionally equipped with an LED power supply.

3. The Device of claim 1, in which the chamber is made of cylindrical, spherical, hemispherical, simple or complex geometric shape with the intersection of curved surfaces.

4. The Device of claim 1, in which the ratio of the sum of all slits or holes areas to the entire area of the inner surface of, at least, one specified chamber wall is optionally minimal from the condition of the air flow passage during inhalation/exhalation or air pumping.

5. The personal respiratory protection device is made in the form of a mask covering at least the respiratory organs, with at least one airway and an attachment mounted on the mask, which is made or contains the Device of claim 4 from the condition that the exit through-slit or hole of such Device faces the airway, and the entrance through-slit or hole faces the surrounding atmosphere and is covered by a breathable filter.

6. The Device of claim 5, in which an air-permeable membrane or filter is additionally located between the mask and the exit through-slit or hole.

7. The Device of claim 5, in which the entrance through-slit or hole is additionally closed by a breathing valve.

8. An air disinfection device containing means of air intake and forced air pumping, an exhaust bell mouth and the Device of claim 1, with an entrance through-slit or hole facing the air intake and pumping means, an exit slit or hole facing the exhaust bell mouth.

Description

[0028] FIG. 1. shows the basic general design scheme of the claimed Device; in FIG. 2.—the basic design scheme of the personal respiratory protection equipment (RPE) based on the Device according to FIG. 1.; in FIG. 3.—the power supply scheme of the RPE; in FIG. 4.—the basic design scheme of the air disinfection (mobile) device with forced recirculation based on the Device according to FIG. 1.; FIG. 5. shows the dependence of the increase in the optical field intensity in a multi-pass irradiation chamber in units of the intensity of the original source on the reflection coefficient of the inner surfaces (average number of passes n=10, 20); in FIG. 6.—the dependence of the increase in the optical field intensity in a multi-pass irradiation chamber in units of the intensity of the original source on the average number of radiation passes (the reflection coefficient from the inner surfaces R=0.90-0.99).

[0029] The claimed group of the invention is based on the well-known principle of treating contaminated air with ultraviolet radiation with a wavelength of 200-280 nm (UVC spectrum) from existing scientific and technical practice. The fundamental difference from the existing technical solutions is the use of a multi-pass optical system (multi-pass air flow irradiation chamber) as the main unit (element) of the claimed devices. This makes it possible to obtain in the internal volume of the inactivation device chamber a repeatedly enhanced relative to the primary intensity of the optical field source, as a consequence, repeatedly reducing the requirements for the power of the ultraviolet radiation source

[0030] The possibility of achieving the result, in this case, is due to the fact that the use of a multi-pass (along the optical path) irradiation chamber with an inner reflecting surface allows to attain multiple reflections of photons participating in the generation of an optical disinfecting field in the internal volume of the chamber, in which, as a consequence, the power of the optical field in the irradiation chamber W.sub.λwill consist of a discrete series waves of different generations.

[0031] Indeed, the power of the radiation source is W=I×hv, where I is the number of photons emitted per unit of time (flux), and hv is their energy. If a photon once passes along its average path through the volume of the chamber, then the power of the optical field is equal to the power of the source. However, if photons experience n reflections on average before they are lost through air slits, then the photon flux is I=I.sub.0+I.sub.0R+I.sub.0R.sup.2+ . . . +I.sub.0R.sup.n-1≈I.sub.0×(1−R.sup.n)/(1−R). Here R is the reflection coefficient of the inner mirror surface, which determines the photon absorption loss by the walls in each reflected generation before they leave the chamber at the n-pass (for an average photon). In turn, for a cylindrical chamber with an internal diameter of 6 cm and a length of no more than 9 cm, the surface area of the irradiation chamber in the computational model will be 2πd.sup.2/4+πdL≈225 cm.sup.2, the volume of πd.sup.2 L/4≈250 cm.sup.3. Thus, according to the previously obtained similarity formula (a), the parameter E.sub.v≈E.sub.v (V.sub.0)/|1n(V/V.sub.0)|≈300/|1n(400/250)|≈640 μJ/cm.sup.3. It should be noted that the above chamber parameters (in the example of using the claimed inactivation device as part of the RPE) are given for clarity of calculation for reasons of ergonomics, ease of operation, maintenance and engineering considerations.

[0032] With reference to FIG. 1. the inactivation device consists of a housing (1) with side walls and end walls (2), a UV LED (3), a UV reflective coating of the walls (4) and air-conducting slits/holes (5) in the end walls. FIG. 1. shows, in essence, a version of the cylindrical shape device, the most technologically feasible in terms of practical manufacturing. However, for a specialist, it is obvious that the specific form of the device chamber in terms of performance and achieving the desired result is optional, and is determined essentially by the technical and technological capabilities of a particular production.

[0033] The possibility of UV radiation reflection by the inner surface of the inactivation chamber walls in practical variants can be realized, for example, by using various coatings applied or glued to the inner surface of the walls—specially treated MgF.sub.2 or other suitable reagent of aluminum foil, thin metal sheets, silver or gold films, etc. Selective examples of coatings based on [6] are presented in the following table 1.

TABLE-US-00001 TABLE 1 Features and Name, dimensions characteristics Price Reflective aluminum mirror ~95% reflectivity, 9% 65 c.u./sheet sheet, class A diffuse reflectivity 1000*120*0.4 mm Reflective aluminum mirror ~99% reflectivity, 3% 100 c.u./sheet  sheet, class A+ diffuse reflectivity 1000*100*0.4 mm (supermirror) Reflective aluminum mirror ~95% reflectivity, 9% 40 c.u./sheet sheet, class A 500*120*0.4 mm diffuse reflectivity Reflective aluminum mirror ~95% reflectivity, 9% 35 c.u./sheet sheet, class A 500*100*0.4 mm diffuse reflectivity Reflective aluminum mirror ~90% reflectivity, 135 c.u./sheet  sheet, class B 1000*120*0.8 mm 10% diffuse reflectivity

[0034] Table 1 clearly shows that it is industrially feasible to use UV reflectors with a reflection coefficient of up to 99%.

[0035] As an example of using an LED with an ultraviolet radiation spectrum with reference to [8], we can mention the LED G6060 of the LEUVA66H70HF00 series with a wavelength of 278 (270-285) nm, radiation power of 70-110 mW, 6.5 V, 350-500 mA, dimensions 6.0×6.0×1.35 mm.

[0036] It is obvious to a specialist that it is also possible to use a combination of LEDs in the form of a group of diodes on one or different boards, including the possibility of locating (fixing) such LEDs at various points in the internal volume of the irradiation chamber. For a similar implementation, for example, refer to the SMD 3535 LED model JZ-UFDC3535FFQUSC-RO with a wavelength of 275 (265-285) nm, current 100-150 mA, 6 V, radiation power 12 MW, dimensions 3.6×3.6×1.62 mm, [9].

[0037] The possibility of practical implementation of the claimed inactivation device within the framework of the RPE will be considered with reference to FIG. 2, where the following positions are indicated by numbers: the RPE mask—6; UV-LED power supply—7; a removable external filter—8; an air-permeable screen—9. Structurally, the inactivation device as part of the RPE can be designed, for example, as an attachment to the respiratory part of the device-respirator in the area of the nasolabial triangle. The inactivation device can also be made in the form of a replaceable cartridge installed in an attachment located on the mask (housing) of the RPE. The inhaled air enters through an external filter (8) to an air slit, located by analogy with a flange, to reduce radiation losses during scattering and reflection from the volume of the irradiation chamber. A similar circular slit serves for the entry of irradiated air into the respiratory organs. When exhaling, the flow goes in the opposite direction through the same chamber, i.e. both inhaled and exhaled air is disinfected with almost the same efficiency.

[0038] An RPE with an inactivation device can also be designed with a visor and two valves behind the inlet filter for inhalation and for exhalation—a separate duct with the exit of disinfected air from the irradiation chamber in the upward direction under the transparent visor. In this version, the constant inflow of UV-treated exhaled air under the visor creates a protective layer (increased pressure of the decelerating flow) for the mucous membranes of eyes in conditions of a leaky cover. The visor itself serves as a barrier to the direct ingress of the infected aerosol into the eyes, as well as a means of forming a protective layer of irradiated exhaled air with increased pressure. It is also possible to use a full facepiece respirator with a plastic or glass transparent window (filter analogues: STALKER-25, 3M 6900 filter 6057, etc.) and an air supply through a respiratory type device (as described above) or through a top nozzle with a vertical irradiation chamber, similar to swimming masks. The latest modification with a vertical nozzle can be equipped with a multi-pass irradiation chamber of a larger size, an exhalation valve and a boost fan to increase comfort during prolonged wearing of the device.

[0039] The question of choosing the dimensions of the slits/holes in the ends of the inactivation device, on the one hand, lies in practical field from the condition of ensuring the comfort of breathing, and, on the other hand, ensuring the presence of photons in the internal volume of the chamber. From the data published in [7], it follows that the average air consumption by human lungs, depending on physical activity and emotional state, is within the range of the flow rate per second for inhalation and exhalation v—500-2000 cm.sup.3/s. Based on this data, to calculate the maximum air flow through the irradiation chamber during human breathing (the dimensions of the slits/holes), it is possible to be guided by the average experimental data on pulmonary ventilation, the true amount of oxygen consumption and heat generation of an adult according to Table 2.

TABLE-US-00002 TABLE 2 State of rest and The intensity of Pulmonary True oxygen Heat characteristics of the external activity ventilation consumption production activity performed kgf*m/min 1/min 1 (n)/min kcal/min Rest — 5-6 0.25-0.3  1.25-1.5  Very light activity —  6-10 0.3-0.5 1.5-2.5 Light activity — 10-16 0.5-0.8 2.5-4.0 Moderate activity 250-450 16-25 0.8-1.2 4.0-6.0 Vigorous activity 450-800 25-40 1.2-2.0  6.0-10.0 Hard activity 800-900 40-50 2.0-2.5 10.0-12.5 Very hard activity  900-1250 50-60 2.5-3.0 12.5-15.0 Maximum effort activity More than 1250 More than 60 More than 3.0 More than 15.0

[0040] For example, by analogy with respirators equipped with removable dust filters, for the comfort of breathing, we will choose the air intake slit area twice as large, since in this case there are two slits, and therefore two hydraulic resistances. The standard respirator has an air inlet/outlet area of about 3 cm.sup.2. Thus, this device has two slits of 6 cm.sup.2 each. The total area of possible radiation loss (leakage) is about 12 cm.sup.2. This allows us to estimate the average number of photon passes before leaving the multi-pass chamber as the ratio of the entire reflecting surface area to the leakage holes area. Therefore, n˜225/12≠18-19 reflections (passes through the chamber).

[0041] Let us determine the increase in the (flux) intensity of the optical field due to the multi-pass reflective system in the irradiation chamber: I/I.sub.0 for reflection coefficients R=0.95 and 0.99. For 0.95, the increase will be about 12, and for 0.99, about 16.5. The difference is not very significant. In further calculations, we will take this coefficient in the amount of 15. Thus, according to inhaled air consumption, the power of the optical field in the chamber is: Wx=E.sub.v×v≈0.3-1.2 W, hence the required power of the emitter for the RPE (mask) is 20-80 mW.

[0042] Practical variant of application of the claimed inactivation device can also be a small-sized air recirculating UV device with low energy consumption, with high technological and price availability for use in transport (subway and passenger railroad cars, bus and minibus cabins, water and air transport cabins and salons, personal vehicles, military and special equipment). The circuit diagram of the device is shown in FIG. 4, where the following positions are indicated by numbers: 10—electric motor; 11—fan; 12—air intake bell mouth; 13—air exhaust bell mouth; 14—radiation shield; 15—removable filter; 16—support stands. As in the case of the RPE, the device is based on the inactivation device FIG. 1. with a multi-pass UV irradiation chamber of the air flow.

[0043] This device is designed for a constant rather high air flow, with forced circulation by using a fan and an electric motor. Air flow is calculated on the basis of an acceptable time to disinfect the air in a given empty room (volume) in an acceptable time; and also on the basis of people in the room, subject to the rhythm of their breathing, depending on the type of their activity and on the condition that this device will inactivate per unit of time at least as many virions of a certain type as all those present could emit if they were infected. To optimize the operation of the device, it can be implemented a multi-level operating mode with several air pumping rates and several UV sources in the irradiation chamber. The principle of the irradiation chamber organization does not differ from the previous device of the RPE. This is a multi-pass optical resonator with slotted holes along the flanges for pumping air.

[0044] As an example of such a device with reference to FIG. 4. it is proposed to use of a group of 3 UVC LEDs full power of 1 W each—UVC G6060 with medium wave 260-275 nm (power consumption of 1-3 W, light power of about 70-110 mW, price from the manufacturer 70-90 $) [8]. In the air pumping mode of 20 liters/sec. (equivalent to calm breathing of 40 people) provides inactivation of up to 99.0% of virions with double-stranded DNA or guaranteed 99.9% of virions such as COVID-19 for irradiation chamber dimensions d=10 cm/L=30 cm.

[0045] The device consumes about 20-25 W of electricity. The main part of it is accounted for by the fan (about 60-70%). The device can operate from on-board (6, 12, 24 V) or general electrical network with an adapter, on-board battery or own autonomous power source. As an example, the same bactericidal efficacy would require 5-7 W of lamp recirculators light power without a multi-pass irradiation chamber (calculation according to [5]), and energy consumption would be about 100 W (˜70% to power the emitters). The weight and dimensions of such a device would be significantly greater.

[0046] The bactericidal efficacy increase of the claimed group of inventions due to application of multi-pass optical air flow irradiation chamber and, as a consequence, increase of optical field intensity is clearly illustrated by graphs of optical field intensity depending on reflection coefficient and average number of reflections (passes) in FIG. 5 and FIG. 6. It can be seen from the presented graphs that, based on the computational and experimental model, the application of the claimed technical solution, namely, the arrangement of a separate multi-pass optical irradiation chamber in an RPE or a mobile air recirculator with UV irradiation on UVC-emitting diodes, can reduce the power of primary sources required to achieve the desired inactivation parameters by more than an order of magnitude. It is obvious that the energy consumption of devices and parasitic heat generation, as well as their cost, are reduced in the same proportion, which makes their production and operation technically feasible and economically attractive.