RU2746384C1 - Bactericidal irradiator - Google Patents

Abstract

FIELD: sterilization.

SUBSTANCE: invention relates to the field of sterilization, and specifically to bactericidal irradiators. A bactericidal irradiator is essentially a cavity with a light source of the bactericidal range of the spectrum placed in the cavity, in which the main part of the inner surface of the cavity of the irradiator is made essentially diffusely reflecting with at least one hole for outputting radiation from the cavity, and the total area of the holes for outputting radiation from the cavity of the irradiator is not less than the surface area of the germicidal radiation source.

EFFECT: fast and effective sterilization of local surface areas.

10 cl, 2 dwg

Description

The claimed technical solution relates to light sources, more precisely to sources of ultraviolet radiation of the bactericidal range of the spectrum (bactericidal irradiators) and is of interest for sterilization tasks, primarily prompt and effective sterilization of surface areas without the use of chemicals or high-temperature treatment.

Sources of ultraviolet radiation are widely used in the tasks of bactericidal treatment of volumes and surfaces. To solve this problem, radiation in the range of 215-300 (230-290) nm, corresponding to a high bactericidal efficiency of radiation, is considered preferable. Low-pressure mercury lamps (RLND), repetitively pulsed xenon lamps, excimer lamps are most often used as sources of such radiation; recently, the use of LED sources has begun.

Low pressure mercury lamps (RLND) are the most widespread, they emit almost monochromatic light with a wavelength of about 254 nm, this wavelength is close to the maximum bactericidal efficiency of light on DNA and RNA molecules (~ 265 nm). For λ = 254 nm, the radiation doses required for sterilization with an efficiency of 90-99.9% have been studied in detail ([1]: Guideline R 3.5.1904-04 "Use of ultraviolet bactericidal radiation for disinfecting indoor air") and for most pathogenic bacteria and viruses are in the range of 1 ÷ 30 mJ / cm2, for Staphylococcus aureus used as a standard sterilized object, the surface dose of radiation for a degree of disinfection of 99.9% is 6.6 mJ / cm2, for a number of viruses for a specified degree of disinfection, a dose of ~ 1 mJ is sufficient / cm2. Typical radiation efficiency of modern RLND is 25-40% (the lower value refers to lamps of short length) with a resource of 8 ÷ 15 thousand hours, today such parameters of the emitter of the bactericidal range are out of competition.

At the same time, in some cases, sterilization by broadband radiation from pulsed xenon lamps or radiation from other parts of the ultraviolet spectrum (including several bands of the bactericidal range at the same time) using excimer lamps can be more effective. Here, the mechanism of inactivation of bacteria and viruses can include not only the effect on DNA or RNA, but also on proteins and other components of the cell, which ultimately provides a greater efficiency of sterilization, and also, according to some researchers, the possibility of realizing a significantly higher degree of inactivation, for example 99.99% and more with a moderate increase in the required dose ([2]: the site of the NPP Melitta company http://www.melitta-uv.ru/technology/work/; [3]: KG Linden, J. Thurston, R. Schaefer, JP Malley, Jr. “Enhanced UV Inactivation of Adenoviruses under Polychromatic UV Lamps.” Applied and environmental microbiology, 2007, vol. 73, no. 23, pp. 7571-7574).

In recent years, LED light sources with a wavelength of 260-280 nm have also been developed, which can be used for bactericidal treatment tasks. However, low power at a very high cost of the emitter (now, per unit of generated radiation power, RLND is hundreds of times cheaper than an LED), as well as low efficiency (<4 ÷ 5%) and resource (within several thousand hours) of LEDs with a radiation wavelength <290 nm does not allow widespread use of such sources, including for high-performance surface treatment.

The sources of bactericidal radiation described above are used both in an open form, simultaneously illuminating large areas or volumes, in this case, the treatment of surfaces and volumes is carried out in the absence of people, and in closed systems (recirculators), when bactericidal light sources are installed in a cavity opaque for radiation and UV sterilization can be carried out in the presence of people ([1]). In the latter case, in the cavity of the irradiator with the source of bactericidal radiation, there are inlet and outlet sections (holes) for pumping the sterilized air flow, and special measures are taken to ensure that UV radiation does not go beyond the cavity, including through the inlet and outlet openings. ... The inner surface of the cavity, as a rule, is made of mirror-reflective polished aluminum or stainless steel, as, for example, in the recirculator Aerolit-400 manufactured by the LIT company ([4]: the website of the LIT company http://www.lit-uv.com/ ru / company /). It is also known to use the diffusely reflecting surface of the irradiator in closed recirculators, which provides a higher than in the case of specular reflection, the effective reflection coefficient in the bactericidal range R up to 90 ÷ 95% or more ([5]: US application No. US 2012/0315184A1). The specified technical solution for a closed recirculator provides high efficiency of air purification due to the multiple amplification of bactericidal radiation in the cavity of the irradiator with a diffusely reflecting surface, however, in principle, it does not allow solving the demanded problem of sterilizing surfaces outside the recirculator.

For surface sterilization, open irradiators are currently used, including irradiators based on tubular mercury lamps with corresponding cylindrical illuminators. However, their use is limited because:

- a significant volume (area) is irradiated simultaneously, which makes it impossible to use the irradiator in the presence of people;

- rather large dimensions of lamps and illuminators make it difficult to localize relatively small areas of the surface;

- moderate luminous fluxes, amounting to ~ 70 ÷ 120 mW / cm2 and ~ 10 ÷ 20 mW / cm2 for traditional low-pressure mercury lamps on the surface of amalgam RLNDs, lead to low luminous fluxes on the treated surfaces and, accordingly, to a significant time of bactericidal treatment with high sterilization effect. For example, at a distance of 2 meters from a 600 mm long amalgam mercury lamp of low pressure, emitting 40 W of bactericidal light, the average radiation intensity does not exceed 0.1 mW / cm2, that is, the time required for the degree of sterilization of 99.9% Staphylococcus aureus is more than 70 seconds. and even for easily inactivated biological objects, a time of> 15 s is required. For non-amalgam lamps, the required time is usually already> 3 ÷ 4 minutes and one minute, respectively. The use of special reflectors (illuminators) can reduce this time by approximately half, but not significantly more, while the overall size of the installation only increases.

Thus, closed recirculators provide sterilization of the air flow pumped through the volume of the irradiator, that is, only the air volume is disinfected, open irradiators sterilize both the volume and surfaces, primarily not in the shadow zone and located not too far from the radiation source. It is not very convenient to process small areas of the surface, including operatively with open irradiators, and due to the large, as a rule, sizes of such devices, and the need to remove people, which does not allow the irradiator to be easily and quickly moved in the treated room (if not only consider complex robotic systems that dramatically increase the cost of processing).

The closest technical solution is the proposed ([6]: application RU 2018117347) bactericidal irradiator, including a light source of the bactericidal spectrum range, placed in a cavity, the main part of the inner surface of which is made essentially diffusely reflecting, characterized in that at least one hole for radiation output from the cavity. That is, in [6], a symbiosis of open and closed irradiators is proposed to some extent, when radiation from the cavity is removed into the external space, but not in all, but in a predetermined direction, which makes it possible to exclude or at least significantly reduce the harmful effect ultraviolet radiation to people in the room. In a preferred embodiment of the known technical solution, a low-pressure mercury lamp is used as the emitter, and the condition (1-R) <s / S <1 is satisfied on the ratio of the areas of the cavity sections with the diffusely reflecting surface S and the sections through which the radiation is removed from the cavity s, where R Is the coefficient of diffuse reflection of radiation from the surface of the cavity.

The idea of the known technical solution is that with a high coefficient of diffuse reflection of bactericidal radiation, even with a relatively small fraction of the area of the hole through which the radiation is removed from the cavity, it is possible to effectively remove and use the main part of the light power emitted by the source in the cavity. Indeed, by analogy with the relations known for integrating spheres for the outputted power of bactericidal radiation Q, we can obtain the following relation:

Q ≈ W * s / [s + S * (1-R)] = W / [1 + S * (1-R) / s] (1),

W is the power of the radiation source in the cavity. Thus, under the condition (1-R) <s / S formulated in [6], a significant fraction of the power of the light source can be removed through the hole of relatively small area and, due to this, a sharp increase in the intensity of bactericidal light at the exit hole and, accordingly, increase the rate of disinfection the corresponding area of the surface to which the radiation output from the cavity is directed. For example, at R = 9 5% and s / S = 0.1, according to (1), about 67% of the radiated power can be removed through the hole in the cavity, and then the light intensity at this hole will be ~ 7 times greater than the average for the same total area (S + s) for an open light source, which will potentially increase the sterilization performance of localized surfaces.

However, the authors of the proposed technical solution have found that the light source located in the cavity in the most common case of using a low-pressure mercury lamp or a pulsed xenon lamp in a relatively small cavity as a light source significantly changes the situation and itself is an effective absorber of the radiation generated by this source itself, which in the general case sharply - multiples (see below) reduces the efficiency of the known technical solution and the sterilization productivity using the known technical solution.

The technical result of the claimed invention is a sharp increase in the productivity and efficiency of sterilization of local surface areas.

The technical result is achieved by the fact that in a bactericidal irradiator, which is essentially a cavity with a light source of the bactericidal range of the spectrum placed in the cavity, in which the main part of the inner surface of the cavity of the irradiator is made essentially diffusely reflecting with at least one hole for outputting radiation from the cavity, moreover, the total area of the holes for outputting radiation from the cavity of the irradiator is not less than the surface area of the bactericidal radiation source.

The power supply unit of the light source is preferably located outside the cavity. Note that here by "light source" we mean all sources of bactericidal radiation located in the cavity, for example, several RLNDs, several repetitively pulsed xenon lamps or RLNDs and a xenon lamp, etc. Accordingly, the power supply units of the light source can be not only one, but also several.

As established by the authors, the proportion of radiation absorbed by the radiation source in a cavity with an essentially diffusely scattering inner surface, the area of which, in a preferred embodiment, significantly exceeds both the surface area of the bactericidal radiation source and the total area of the holes for radiation output, is proportional to the surface area of the source. In this regard, relation (1) for a source of finite dimensions in a cavity with a mainly diffusely reflecting surface must be corrected as follows:

Q ≈ W * s / [s + S * (1-R) + kSi] = W / [1 + S * (1-R) / s + kSi / s] (2),

Si is the surface area of the source of bactericidal radiation, k is the coefficient (k ≤ 1) describing the fact that part of the absorbed radiation can be re-emitted by the source into the volume of the cavity: if there is no repeated re-radiation, then k = 1, if all the absorbed radiation is again is re-emitted, then k = 0. The authors' assertion is that for RLND (first of all) and pulsed tubular xenon lamps, the use of which is preferable within the framework of the proposed technical solution (as well as for LEDs), the coefficient k is significantly greater than 0 and even> 0.5. It is for this reason that when the condition s ≥ S formulated by the authors in the first paragraph of the proposed technical solution is fulfilled, and the efficiency of radiation output from the cavity increases significantly - of course, while the condition of the paragraph of the formula of the claimed technical solution (1-R) <s / S is fulfilled.

It should be noted that formally from (2) it follows that it is advisable to maximize the ratio s / S. However, this is not the case, since (1) - (2) are true for the case of radiation that is sufficiently well "mixed" in the cavity of the feed due to repeated diffuse re-reflection of radiation. Otherwise, the amplification effect described above will not occur, and as the s / S ratio increases, the situation will increasingly approach the case of an open radiator, which is not of interest here. In this regard, it is advisable to choose s / S <0.4, preferably s / S <0.2 and, if possible, even less.

This condition means that it is necessary to choose a material with R> 90%, preferably R> 95%, as the material for the diffusely scattering cavity of the irradiator. Such materials are known; among the relatively expensive ones, one can specify expanded fluoroplastic (e-PTFE), which provides in the bactericidal range due to multiple rescattering at the pore-fluoroplastic boundaries with a thickness of 2 mm R ~ 96%, spectralon with R ~ 98%, etc. - Quite a lot of materials are known that provide a high effective reflection coefficient of incident radiation precisely due to its multiple rescattering in an optically inhomogeneous transparent material. In addition, in order to realize diffuse scattering, an appropriate coating can be used on the irradiator material that is not necessarily diffusely scattering or simply poorly reflective of bactericidal radiation - for example, a coating of the Spectraflect® type from LABSPHERE, INC. with an effective diffuse reflectance of about 93% ([7]: https://www.labsphere.com/labsphere-products-solutions/materials-coatings-2/coatings-materials/spectraflect/). In this case, the body of the irradiator can be made of a wide range of materials from plastics to metals with a diffusely scattering coating applied to its inner surface.

Of the relatively cheap materials for making the feed cavity, we indicate primary fluoroplastic-4 (PTFE), which provides an effective diffuse reflection coefficient of at least 92–93% at a thickness of 4 mm.

Note that for a diffusely reflecting surface, the "reflection" of the incident radiation occurs at angles that differ from the specular one; such surfaces are also called scattering. For an ideal diffusely reflecting (scattering) surface, the well-known Lambert's law is fulfilled: the brightness of such a surface is the same in all directions. There are no materials that "reflect" light in strict accordance with Lambert's law, usually reflected (that is, not absorbed and not transmitted through the body) light has both specular and diffuse components. By a diffusely reflecting surface in the present technical solution, including all claims, we mean essentially a diffusely reflecting surface - one for which the diffuse component of the scattered (reflected) light significantly exceeds the mirror component, for example, a surface for which the fraction of the diffuse component in reflected light exceeds ⅔ (≥70%).

For the implementation of the present invention, it is essential not only that diffuse reflection allows not only to obtain a reflection coefficient> 90% unattainable for specular reflection in the wavelength region of ~ 260 nm, but also to effectively "mix" the radiation in the cavity and thereby realize uniform illumination of the hole ( holes) through which radiation is removed from the cavity, even in a situation of a sufficiently large size of such a hole.

In a preferred embodiment of the claimed invention, tubular pulsed-periodic inert gas lamps are used as a source of bactericidal radiation, as well as, first of all, tubular RLND, including those and other U-shaped lamps for the purpose of greater compactness. The preference of low-pressure mercury lamps is associated with their high efficiency, significant service life up to 10 thousand hours and more, as well as good bactericidal efficiency and low cost.

As mentioned above, the power supply unit of the light source included in the irradiator is located outside the cavity in the main embodiment of the proposed technical solution. When it is located in the cavity of the feed unit, the surface of the power supply must also be taken into account when calculating the fraction of radiation output from the cavity. Since usually the surface of the power supply absorbs ultraviolet radiation well, the efficiency of radiation output when the power supply is in the cavity can be significantly reduced. When placing the power supply unit in the cavity of the irradiator, it is preferable to make its surface also diffusely reflecting bactericidal radiation, for example, using appropriate coatings or making its body made of fluoride, etc.

When manually processing small areas, it is convenient to implement the proposed technical solution, when the cavity with a diffusely reflecting inner surface has an essentially axisymmetric shape, bounded by two ends, with a hole for radiation output in one of the ends of the cavity.

A corresponding example of the implementation of the specified variant of the claimed invention is shown in Fig. 1, here 1 - a cavity made by turning from a rod of primary fluoroplastic-4 in the form of a cylinder with an open end with an inner diameter of 95 mm, a height (determined by the distance from its open end to the "bottom" of the same diameter) about 140 mm and a wall thickness of the cylinder 5 mm. The cylinder contains a source of bactericidal radiation, which is a compact U-shaped mercury lamp from OSRAM of the PURITEC HNS G23 series with a power consumption of 5 W and an emitted power of about 0.9 W: 2 - lamp base with terminals for supplying power 3, which "Hidden" in the handle of the feed with a diameter of ~ 45 mm and a height of ~ 65 mm (the "lower" part of the feed of a smaller diameter). Heated electrodes 4 are used to generate current in the lamp. The walls of the lamp 5 with a thickness of about 1 mm and an outer diameter of 12 mm are made of quartz glass transparent for radiation with a wavelength of 254 nm, the working medium of lamp 6 during the generation of radiation consists of mercury vapor with a pressure of ~ 1 Pa and a mixture of argon with neon with a pressure of ~ 500 Pa. The length of the U-shaped discharge gap between the electrodes is about 130 mm, the total length of the absorbing column of mercury atoms in the lamp is up to 135 mm.

Thus, in the described example, the area of the hole for radiation output from the cavity is s ≈ 71 cm2, the area of the diffusely scattering surface of the illuminator is S ≈ 480 cm2, and the area of the side surface of the mercury lamp is Si ≈ 50 cm2. The measured average radiation power in the plane of the open end of the cylinder was 5.5–6.2 mW / cm2 (note that the fairly good stability of the radiation power distribution over the cross section of the end with a relative variation of less than 10% is due to the fact that S is many times greater than s), the total power of the output bactericidal radiation Q ≈ 420 mW or about 45% of the total lamp power in an open space, which is 20–25 times more than at the same distance from the lamp in an open space (without an irradiator).

For the indicated values of the areas and W = 950 mW, the calculation by formula (2) at R = 93% and k = 1 gives Q ≈ 435 mW in good agreement with the measured value (for R = 91%, the same calculated value corresponds to k ≈ 0, eight).

With an increase in the diameter of the cylindrical cavity with the lamp to 120 mm, the total power of the output radiation slightly increased - up to ~ 470 mW; however, the uniformity of the distribution of the light intensity over the cross section of the open end of the feed was significantly deteriorated, which is undesirable.

For comparison, a bactericidal irradiator with the same source of bactericidal radiation was made from the same fluoroplastic, but the dimensions of the cavity of the irradiator with the same wall thickness of 5 mm were reduced to the following values: inner diameter 32 mm, height 75 mm. Thus, in the “control” version of the irradiator, the area of the hole for radiation output from the cavity is s ≈ 8 cm2, the area of the diffusely scattering surface of the illuminator is S ≈ 81 cm2 (the S / s ratio is greater than in the first example, the condition (1-R) <s / S is also satisfied), the area of the side surface of the mercury lamp (the surface area of the emitter) is Si ≈ 50 cm2, that is, the condition s> Si is violated. The measured average radiation power in the plane of the open end face of the cylinder was ≈14 mW / cm2, which is 3–3.5 times higher than in the case of an open RLND. The total power of the outputted bactericidal radiation is Q ≈ 115 mW or about 12% of the total lamp power in the open space, this value is also close to that calculated by (2) at R = 93% and k = 1.

Thus, the use of the proposed technical solution makes it possible to provide a flow on a fixed surface area 20 ÷ 25 (or more) times greater than for an open lamp and the total outputted flow of bactericidal radiation is several times greater (in a specific example, four times) than according to the prototype. Accordingly, the productivity of local surface treatment can be increased by the same factor. In particular, for the above-described geometry of the irradiator with an output radiation power of more than 400 mW, a dose of 6.6 mJ / cm2 (sufficient to obtain a sterilization degree of at least 99.9% for most bacteria and viruses) provides a surface disinfection performance of 60 cm2 / s or about 1 m2 in 3 minutes (that is, passing the open end of the described cavity along the treated surface at a speed of 5 ÷ 6 cm / s, we get a completely sterilized "trace" of the movement of the open end); for microorganisms with a lower required bactericidal dose, treatment can be carried out even times faster.

Note that the proposed technical solution provides high-quality sterilization of the surface with low operating costs: for processing 1 m ² in 3 minutes, no more than 1500 J of electricity is spent - this is less than 0.0005 kWh, that is, no more than 0.3 kopecks. at a cost of electricity of 6 rubles / kWh (and even lower costs with a lower required bactericidal dose).

A similar illuminator can also effectively use compact tubular xenon lamps, for example, flash lamps of the INP type produced by Zenit Trading LLC ([8]: http://www.znt.ru/index.php/catalog/flash-lamps-inp ) or similar, in particular, lamps of the INP-3 / 45A type with a tube diameter of 3 mm and an interelectrode distance of 45 mm. In a preferred embodiment, the lamp can have a U-shape, and the electrodes and, in general, all parts of the lamp where no radiation is generated (with the exception of the discharge channel) are brought out of the cavity of the feed, for example, into the "handle" of the feed (see Fig. 1) ... Note that in the variant of using a tubular flash lamp according to the formula of the proposed technical solution, it is possible to use more compact bactericidal irradiators, since the surface area of the emitter in this case is significantly less than that of a compact RLND - for example, for the indicated lamp Si ≈ 4.2 cm2, then there is already with a hole diameter at the open end of 4 cm, the area of the hole for radiation output is three times greater than Si.

Thus, the proposed technical solution provides such streams of bactericidal light from a compact bactericidal irradiator, which can be effectively used for local operational (almost instantaneous) sterilization of relatively small open surfaces, including during operations and, if necessary, repeatedly or periodically), in cases of allergy on sterilizing chemical reagents, for special surfaces and in other situations, including sufficiently fast processing of surfaces of a large area.

It is also important to note that the cavity of the feed can be not only cylindrical, but also conical, and also have a different shape; in a preferred embodiment, the cavity of the feed has an axisymmetric shape, this, as a rule, simplifies the manufacture of the feed.

In some applications of the proposed technical solution, the shape of the hole for outputting radiation from the cavity of the irradiator can be optimized in advance according to the shape of the object being processed - for example, a bactericidal irradiator for sterilizing banknotes can have a rectangular outlet section corresponding to the size of the banknotes. Or, for sterilizing treatment of the surface of the escalator handrail, the shape of the hole for removing radiation from the cavity can correspond to the section of the escalator handrail tape, etc. In these cases, the diffuse nature of the reflection of radiation from the main part of the surface of the cavity also provides sufficient uniformity of the light flux on the surface to be treated.

The escalator belt processing also provides an example of the possibility of using a substantially different feed geometry from that shown in FIG. 1. In this case, a cylindrical cavity with closed diffusely reflecting ends and an open groove along its generatrix and a straight RLND (or several RLND) located coaxially with the groove and the axis of the feed cavity may be preferable. For example, (this is not the only possible option) for processing a tape 10 cm wide, an irradiator with a cylindrical cavity with a diffusely reflecting surface 10 cm in diameter and 15 cm in length can be used, in which an RLND with a diameter of 10 mm with an interelectrode distance of 15 cm can be used (the electrode nodes are removed outside the cavity, and the ends of the cavity are also made diffusely reflecting). The cavity has a groove 12 cm long and 5 cm wide (two grooves 2.5 cm wide), etc. Through the specified groove, bactericidal radiation is removed from the cavity and processes the moving escalator belt. In this example, the area of the diffusely reflecting surface of the cavity (taking into account the ends) is S ≈ 550 cm ² , the area of the hole (in this case, a rectangular groove) is s = 60 cm ² (S / s ~ 9), and the surface area of the emitter is Si ≈ 47 cm ² , as can be seen formulated in paragraphs 1-3 of the claims, the conditions are satisfied for, for example, a fluoroplastic cavity with R ≈ 93%.

Similarly, the cavity of the irradiator for disinfection of the same escalator tape can have a spherical shape, for example, 15 cm in diameter with the same groove 12x5 cm ² (S≈620 cm ² , s ≈ 60 cm ² , S / s ~ 10) with a similar RLND located by the diameter of the sphere.

In addition to the different geometry of the cavity of the irradiator (cylinder-sphere-cone, etc.), when solving a specific problem, the relative position of the irradiator and the treated (sterilized) surface may be different. So, when sterilizing the same escalator tape, the groove of the feed and its axis of symmetry can be located not only "across" the direction of movement of the tape, but also along this direction. For example, a straight tubular RLND manufactured by Osram, Philips, etc., with an energy consumption of 16 W, an interelectrode distance of about 235 mm, a diameter of 15 mm, and a radiated power of about 4.5 W can be used as a source of bactericidal radiation (Philips TUV 16W G16T5 and similar) ... A cylinder with a diameter of 20 cm and a length of ~ 23.5 cm can be used as the cavity of the irradiator (the lamp electrodes are placed outside the cavity in order to exclude radiation losses due to absorption by these sections of the lamp) with diffusely scattering ends and a groove 12 cm wide (for processing the side sections of the tape) length 15 cm, with this geometry S ≈ 1900 cm ² , s = 180 cm ² (S / s ~ 10), emitter Si ≈ 110 cm ² . In this case, the power of useful bactericidal radiation is ~ 2 W and for a belt speed of 40 cm / s the bactericidal dose will be ~ 8 mJ / cm ² - sufficient for the proportion of microorganisms. If it is necessary to provide a large dose, it is possible to use the lamp and the cavity of the irradiator proportionally longer with the same width and proportionally with the greater length of the slot.

We will specifically point out that in the preferred embodiment of the inventive irradiator, electrode assemblies, lamp caps, etc. are removed outside the cavity of the feed, as described in the examples above.

In an embodiment of the proposed technical solution, first of all, when a high coefficient of diffuse reflection is provided by applying a suitable coating to the material of the cavity, the cavity can be made composite. For example, in the axisymmetric version of the cavity according to claim 6 of the claims, it can include two parts - two "halves", when the cavity consists of two "half-cylinders or cones with a bottom-handle" symmetrical along the axis of symmetry of the cavity. It is technologically simpler and more convenient to apply a corresponding diffuse-reflecting coating or a layer of an appropriate material, for example, a layer of expanded fluoroplastic, to such component parts of the cavity. In this case, the material of the cavity itself can be selected as optimal without taking into account the requirements of a high diffuse reflection coefficient, for example, a material with the required thermal conductivity (to maintain the optimal temperature in the cavity of the irradiator) or made of material opaque for bactericidal radiation is selected, which guarantees the safety of a person (operator) using the inventive bactericidal irradiator (a small proportion of bactericidal radiation can "seep" through the diffusely scattering, but non-absorbing radiation material.

In connection with safety requirements, in the preferred and basic embodiment, the body of the irradiator as a whole is made opaque for bactericidal radiation (and even for ultraviolet radiation in general). This can be done in various ways, for example:

- the body of the irradiator is made of a material that is opaque for bactericidal radiation; a diffusely scattering coating is applied to the inner surface of the cavity, or a layer of diffusely scattering material is attached to it: a layer of expanded fluoroplastic, a layer of ordinary fluoroplastic, etc .;

- the body of the irradiator is made of a diffusely scattering material, on the outer surface of which a layer of material that absorbs bactericidal radiation is applied - this can be a plastic layer, a metal layer (literally enough aluminum foil) or paint.

In a preferred embodiment of the claimed invention, the hole for outputting radiation from the cavity of the irradiator is closed with a material transparent for radiation, for example, a plate of transparent in UV (including in the bactericidal range) quartz glass, magnesium fluoride (MgF ₂ ), lithium fluoride (LiF), leucosapphire etc. That is, in this embodiment, the cavity with the radiation source is separated from the external space, including the cavity is made sealed, while the radiation is removed from the cavity through the material transparent for radiation. In this case, in particular, the ingress of dust into the cavity is excluded (especially when the lamp is turned off, when the air temperature in the cavity decreases, inducing air flow from the outside into the cavity), which can be significant, since dust settling on the walls of the cavity gradually reduces the diffuse reflection coefficient. Moreover, the elimination of dust accumulation in the cavity of the feed allows the use of diffusely scattering materials in the irradiator, the accumulation of dust by which is possible due to their porous structure - for example, expanded fluoroplastic, which provides a significantly lower value (1-R) compared to conventional fluoroplastic, which automatically increases the efficiency of the irradiator. The tightness of the cavity also provides an additional level of safety in the event of a lamp leakage when using lamps with mercury-containing gas mixtures as light sources.

In one of the embodiments of the claimed invention, the cavity of the irradiator is filled with gas, which, unlike air, is transparent not only in the bactericidal range of the spectrum, but also in the shorter wavelength region, including part of the VUV spectral region, at least up to a wavelength of 185 nm (resonant transition of a mercury atom) and even 170 ÷ 175 nm (emission band of xenon dimers). It can be nitrogen or inert gases - for example, xenon, transparent at least up to wavelengths of 150 nm (and much less for krypton and lighter inert gases). In this case, for example, radiation from a resonant transition of a mercury atom with a wavelength of 185 nm from a singlet excited state (for RLND made of quartz transparent to VUV) or broadband short-wave radiation from pulsed xenon lamps can be brought to the output window of the feed. Accordingly, by placing the output window of the irradiator near the surface to be treated, it is possible to bring to it, for example, high-energy photons with a wavelength of ≈185 nm (the path length of such photons in air with typical humidity is 6 ÷ 8 cm), which effectively provide not only bactericidal treatment ( together with photons of 253.7 nm of the second resonance transition of the mercury atom from the triplet excited state), but also the decomposition of the overwhelming majority of chemical compounds, including harmful compounds and toxins, which may be of independent interest for many applications, including special ones. The effect of exposure to shorter-wavelength radiation can be significant in the case of repetitively pulsed inert gas lamps, including the well-known xenon lamps. In this case, it may be preferable to make the lamp bulb from a material with a high transmittance in the short wavelength region - special types of quartz glass, leucosapphire, etc.

In this preferred embodiment, the generation of ozone by VUV radiation near the exit window (s) of the cavity of the irradiator can also be useful, ozone, the strongest oxidizing agent, also effectively decomposes chemical compounds and inhibits biological objects. It is important and useful here that ozone is generated locally only in the region near the exit window (s) of the feed cavity.

Some quartz sarks (for example, KU-1, Suprasil), as well as leucosapphire, lithium or magnesium fluoride, etc., can be used as transparent materials in a close VUV range.

For the indicated version of the emitter, it is also important that a sufficiently high diffuse scattering coefficient in pure PTFE-4 and its "derivatives" such as expanded PTFE is realized in the near VUV range, at least up to wavelengths of ~ 170 ÷ 185 nm. At the same time, the reflection coefficient is still lower than in the region of 260 nm, and for this reason, the number of re-reflections (rescattering) in the cavity of the irradiator, which is preferable for outputting VUV radiation, should be less than for radiation of the main bactericidal range. Since, in the first approximation, the number of multiple reflections is ~ S / s (even taking into account absorption in the radiation source), then for VUV radiation the preferable S / s ratio can be ~ 5 ÷ 7 (for the bactericidal range and the effective diffuse scattering coefficient of 96% without significant losses it is possible use cavities with a ratio S / s ~ 10 ÷ 15. We also point out that, if it is important to use VUV radiation, the operating mode of the radiation source and / or the composition of its gaseous medium can be appropriately corrected - it is known, for example, the difference in the optimal conditions for generating radiation on resonance transitions of the mercury atom at 185 nm and 254 nm in the RLND.

One of the variants of the implementation of the cavity with the aperture closed by the transparent plate for the radiation output is shown in Fig. 2, on which 7 is a plate transparent for bactericidal radiation for removing radiation from the cavity, 8 is a sealing gasket, 9 is a flange fixed to the cavity 1 by a threaded connection, the rest of the designations coincide with those indicated in Fig. 1. Note that the forward-protruding (in the direction of light propagation) "visor" 10 of the flange additionally protects the operator from UV radiation scattered by the treated surface; in a preferred embodiment, this kind of protective "visor" protrudes at least 10 mm from the end of the hole (size h in Fig. 2), through which the radiation is removed from the cavity of the feed - for example, in such a way that the "visor" is close or practically close to the surface to be treated, including clearly bordering the area of the surface to be treated. In this case, the entire flange or its "visor" (in the variant of a composite flange) can be made of a material transparent for visible light and opaque for bactericidal radiation (for example, from plexiglas or "ordinary" glass) - in this case, the operator can safely control the radiation being processed area of the surface. The connection of the plate to the cavity can be performed by other known methods, for example, using glue, etc. (as well as the connection of the part of the flange ("visor") transparent for visible radiation with the rest of the flange.

We point out that, in a preferred embodiment, the described protective "visor" can be part of the irradiator even in the case when the cavity of the irradiator is open, that is, a plate transparent in the bactericidal range for radiation output is not used. The surface of the "visor" can be cylindrical or conical, in FIG. 2 shows a variant with a conical surface, the opening angle of the cone Ф can be quite large - up to 120 ÷ 150 degrees, the angle Ф can be negative ("converging" cone). Replacing one "visor" with another also allows you to quickly change the size of the surface area processed by the irradiator. When a bactericidal emitter of VUV radiation is removed from the cavity, the "visor" additionally limits the region of generation of ozone and OH radicals during the interaction of such radiation with oxygen and water vapor in the air, respectively, which, as a rule, is useful for increasing the effectiveness of the impact on the treated surface and volume ...

Note that during operation, the cavity of the feed is additionally heated due to heat release in it (although the temperature rise is small in most cases - the heat release is relatively small, and the surface area of the cavity is large enough, so that the heat flux to the walls of the cavity, as a rule, turns out to be <0 , 03 W / cm2, which corresponds to a slight overheating). Nevertheless, overheating corresponds to an increase in pressure in the cavity, with an increase in temperature by 5 ÷ 7 ° C, the excess pressure in the cavity will be ~ 2 kPa (note that the increase in pressure is determined by the average temperature of the cavity, which is much less than the operating temperature of the walls of the RLND ~ 40 ÷ 45 ° C ) and for a hole diameter in the cavity of 95 mm, the excess force acting on the transparent plate will be ~ 15 N. Such additional stresses do not pose a problem for even thin quartz plates or plates of another material, as well as for fixing these plates with glue or flanges.

However, with a significant increase in the size of the cavity and, accordingly, the size of the hole for outputting radiation from the cavity, in a preferred embodiment, instead of one hole of a large area, it is possible to use several holes of a smaller diameter. In this case, the holes for outputting radiation can be located on a "supporting lattice" corresponding in strength with a high coefficient of diffuse radiation scattering from the side facing the cavity. That is, the end face of the cavity of the irradiator, for example, can be made of a fluoroplastic plate of the required thickness with several holes for radiation output from the cavity, on each a plate transparent for radiation is installed, which is fixed with glue, a flange, etc. The size of an individual hole, the thickness of the plate and the width of the gaps between the holes are determined by the condition required to withstand the excess pressure of the strength of both the transparent plates and the "supporting grid".

Since the compressive strength of many materials and joints (for example, adhesive) is much stronger than tensile strength, in one embodiment, the cavity of the feed is sealed at a temperature higher than the temperature of the cavity during operation of the radiation source. In this case, both with the light source turned on (there is heat generation) and the light source turned off (there is no heat generation), the gas pressure in the cavity can be less than the external one - this will automatically ensure a good quality and resource of the adhesive joint, additional fixation of the gaskets, etc. , which simplifies and improves the sealing of the cavity. Note that for this type of cavity sealing, it is necessary to take into account possible variations in atmospheric pressure.

As mentioned above, low pressure mercury lamps in many cases seem to be optimal for many sterilization tasks due to their high bactericidal efficiency and efficiency, low cost and high resource. However, in addition to their own absorption, these lamps have a disadvantage, which is significant for the tasks of operative sterilization: they require a significant time to reach the operating mode after turning on the power - from tens of seconds for compact non-amalgam lamps to several minutes for amalgam lamps. The main reason for the delay is associated with the need to heat the surface of the RLND flask to a temperature that provides the required concentration of mercury vapor: ~ 40 ÷ 45 ° C for the non-amalgam version of mercury lamps and ~ 100 ÷ 120 ° C for amalgam lamps. Note that there is no such problem for inert gas flash lamps, excimer and LED sources.

This problem can be solved in at least two ways.

1. RLND can work (be turned on) constantly or turned on at the beginning of a work shift and turned off at its end, etc., and the hole for radiation output is closed with an opaque cover (diaphragm). During the use of the radiation of the bactericidal irradiator for sterilizing the surface, the cover is removed or the diaphragm is opened (including automatically) and the treated surface is irradiated. The specific options for the implementation of such a "shutter" can be different, including the diaphragm can be opened for a predetermined period of time in the same way as it was done with the shutter of film cameras. Specific implementations of this embodiment of the technical solution are well known to those skilled in the art.

Continuous operation of the lamp in the described embodiment does not lead to any significant additional costs. In fact, with a power consumption of 5 W for 40 hours of operation (work week), electricity consumption is 0.2 kWh, which, at a price of 1 kWh in Russia, 6 rubles corresponds to a cost of ~ 1 ruble per week, and for the entire operating time of such a lamp ~ 10 thousand hours of electricity consumption will be about 50 kWh with the cost of paying ~ 300 rubles (in the case of a full load, an area of 20 or more hectares can be sterilized!).

2. The cavity can accommodate at least one additional source of heat release (for example, ohmic heating), the constant operation of which ensures the maintenance of the temperature of the RLND quartz walls required for the operation of the lamp. In this case, when power is applied, the lamp begins to generate radiation much faster, since the heating time of the electrodes is minimal and, in addition, the heating of the electrodes can also be turned on all the time - then the RLND radiation turns on almost instantly. Accordingly, for the duration of the lamp operation, the power supply unit of the additional heater is turned off (or its power is significantly reduced) and again turned on at full power after the discharge in the RLND is turned off, that is, the power supply units of the radiation source (RLND) and the additional heat source are synchronized. In this case, the operating time of the RLND (duration of radiation of bactericidal light) can be programmed in various ways, which are well known to specialists in this field.

The latter technical solution is preferably used in the variant when the source of bactericidal radiation (RLND) is located in a sealed cavity. In this case, the heat transfer to the environment is reduced and the power consumed by the heater is minimal, and the temperature is practically the same throughout the entire volume of the cavity. The temperature required to maintain the temperature in the cavity of ~ 40 ° C is minimal if the walls of the cavity of the feed or at least one layer of the cavity is made of a material with low thermal conductivity, for example, polystyrene with a coefficient of thermal conductivity ϰ = 0.9 * 10-3 W / (cm * deg ), while the thermal conductivity of fluoroplastic is 2.6 times higher than that of polystyrene.

The optimal power of the additional heater for a given shape and material of the cavity, as well as for a specific model of RLND, is determined experimentally, while the cost of electricity consumed by such an additional heat source remains insignificant. It is also important here that when the RLND is placed in a sealed cavity, the temperature regime of its operation changes in comparison with the case of placing the lamp in free space, which can lead to some correction (towards a decrease) in the power consumed from the power supply unit and even to a certain increase in the efficiency of the lamp, since under conditions of difficult heat transfer in a sealed cavity, a smaller part of the power is spent on maintaining an elevated temperature of the lamp walls.

A small required power of additional heat release can be obtained from a source of small area, that is, the heat source will have a minimal effect on the light field in the cavity and the efficiency of radiation extraction from it, especially if the surface of the source has a high coefficient of diffuse reflection of radiation - for example, made of an appropriate material or the surface is coated with an appropriate coating as described above.

When used in the claimed technical solution of amalgam RLND placed in a hermetically sealed cavity with radiation output through a material transparent for bactericidal radiation, it may be preferable to use two heat sources, each of which solves different problems:

- the first source of heat release provides the required temperature of the amalgam (usually 100 ÷ 130 ° C, depending on the specific composition of the amalgam), that is, the temperature at which the pressure of saturated mercury vapor over the amalgam is ~ 1 Pa - the optimal value for RLND;

- the second source (sources), when the amalgam is heated (when the first source is running), provides a temperature in the cavity, including the temperature of the RLND walls, such that saturated mercury vapors are guaranteed not to settle on the lamp walls, this is ~ 45 ÷ 50 ° C.

In other words, for an amalgam RLND, there is no need to warm up the entire surface of the lamp to the amalgam temperature, which saves significant power while maintaining the lamp in a constantly operational state. If the amalgam RLND uses several amalgam "spots", then it is preferable to use an appropriate number of local heating sources.

In most cases, the source of bactericidal radiation also emits visible light (for example, RLND emits in the visible range ~ 2 ÷ 5% of the total radiated power), which makes it easier for the user to control the correct operation of the bactericidal emitter. In some cases, it may be expedient and user-friendly to indicate bactericidal radiation invisible to the eye, for example by means of a phosphor emitting visible light under the action of an ultraviolet light source. The phosphor can be applied to a small area of the plate through which the bactericidal radiation is removed from the cavity of the irradiator.

Thus, the application of the proposed technical solution makes it possible, at low cost, to provide effective high-performance sterilization of local surface areas with bactericidal radiation, including, if necessary, areas of the surface of the human body and clothing, including in the presence of other people. With the help of the proposed technical solution, it is also possible to promptly clean surfaces not only from bacteriological objects, but also from a wide range of chemical compounds. Here we also specially note the "absolute sterility" of radiation, when using which it is fundamentally impossible to introduce a microorganism, toxin, etc. onto the surface to be treated.

Compactness, low weight and low power consumption, the possibility of processing a selected surface area, in principle, allows the use of this type of bactericidal irradiators as part of small-sized robotic complexes, install such irradiators on drones with the possibility of autonomous operation for a sufficiently long time with power from an autonomous storage device. For example, lightweight, small-sized, cheap and far from the most energy-intensive batteries used in smartphones store energy, which is enough for a sufficiently long battery life: a capacity of 6000 mAh at a charging voltage of 4.2 V corresponds to an electrical energy of ~ 90 kJ, when discharged to a voltage of 2 , 8 V is released over 30 kJ, which corresponds to the battery life of the bactericidal irradiator for more than 1.5 hours. More power hungry batteries will easily provide a battery life of three to four hours.

The claimed technical solution is applicable to various specific sources of bactericidal light and methods of supplying them (continuous direct current discharge, pulse-periodic discharge with a different shape of a separate pulse and with a different frequency of their repetition, etc.), the geometry of the emitter (tubular lamp, ball lamp , U-shaped lamp, etc.), the material from which the lamp is made (for example, a leucosapphire xenon flash lamp can provide high radiation power in the short-wavelength range), the shape and size of a cavity with a diffusely reflecting inner surface, methods for realizing diffuse reflection due to the material from which the cavity or its inner layer is made (fluoroplastic made using different technologies, expanded fluoroplastic, etc.), or due to the appropriate coating on a material selected from other considerations, as well as a combination of these solutions. Various materials can be used as the material of the plate that hermetically closes the hole for removing bactericidal radiation from the cavity; the plate may not be flat, and the shape of the corresponding hole is not round.

The specific implementation of the additional heat source in the cavity can be different. The method of synchronizing the operation of the RLND and the heat source, the principle of operation of the diaphragm or shutter, if the RLND works constantly, as well as the method of preliminary setting the duration of the radiation pulse from fractions of a second to the continuous mode of light generation, can be different. This means that the composition of the bactericidal irradiator can include, among other things, a control system that controls the operating mode of the emitter, including its resource (operating time counter), etc.

To satisfy any possible specific requirements, changes in the above-described options for implementing the proposed technical solution, obvious to qualified specialists in this area, can be fulfilled. This also applies to a specific version of the material and geometry of the cavity with a diffusely reflecting surface, holes for radiation output from the cavity and the material of the plate (plates) transparent for radiation, optimization of the power supply of the bactericidal radiation source and ensuring its output to the operating mode, implementation of the control system bactericidal irradiator, etc.

Claims (10)

1. Bactericidal irradiator, which is essentially a cavity with a light source of the bactericidal range of the spectrum placed in the cavity, in which the main part of the inner surface of the cavity of the irradiator is made essentially diffusely reflecting with at least one hole for outputting radiation from the cavity, and the total area of the holes for output of radiation from the cavity of the irradiator is not less than the surface area of the source of bactericidal radiation. 2. A bactericidal irradiator according to claim 1, characterized in that the emitter is a low-pressure mercury lamp, and the area of the side surface of said lamp is less than the total area of the holes for removing radiation from the cavity. 3. The bactericidal irradiator according to claim 1, characterized in that for the ratio of the total area of the holes for outputting radiation from the cavity of the irradiator s to the area of the diffusely reflecting inner surface of the cavity of the irradiator S, the condition (1-R) <s / S is satisfied, where R is the coefficient diffuse reflection of the inner surface of the cavity. 4. The bactericidal irradiator according to claim 1, characterized in that the diffuse reflection coefficient of the main part of the surface of the cavity of the irradiator R is at least 0.9, preferably at least 0.95, and the ratio of the total area of the holes for removing radiation from the cavity to the area of the diffusely reflecting surface s / S <0.4, preferably s / S <0.2. 5. The bactericidal irradiator according to claim 1, characterized in that the cavity of the irradiator has a substantially axisymmetric shape, bounded by two ends, with an opening for radiation output in one of the ends of the cavity. 6. A bactericidal irradiator according to any one of paragraphs. 1-6, characterized in that the cavity of the feed is made composite. 7. The bactericidal irradiator according to claim 1, characterized in that at least one opening in the cavity of the irradiator is closed with a material transparent for bactericidal radiation. 8. The bactericidal irradiator according to claim 7, characterized in that the cavity of the irradiator is made sealed. 9. A germicidal irradiator according to claim 8, characterized in that the cavity is filled with a gas mixture that is transparent for radiation with a wavelength of up to 185 nm, preferably transparent for radiation with a wavelength of up to 170 nm. 10. The bactericidal irradiator according to claim 2, characterized in that at least one additional heat source is located in the cavity of the irradiator.

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