RU2031659C1 - Apparatus for disinfecting air and surfaces - Google Patents

Abstract

FIELD: express disinfecting of air in rooms of medical clinics and opened surfaces without using of disinfecting solutions and chemical preparations. SUBSTANCE: apparatus has the impulse gas discharge lamp 8, mounted in the holder 7 of the irradiator 6 and connected with the control unit 2 for feeding power. High power pulse of ultraviolet irradiation is formed by the lamp 8 upon discharging (through it) of an accumulating capacitor, whose charge is being performed by a direct-current voltage source and whose discharge is being initiated by a generator of high-voltage firing pulses, inductively coupled with the discharging contour. Parameters of the discharging contour are mutually connected by a designed relation. In order to lower formation of ozone and for cooling, the lamp 8 is embedded to the coaxial pipe 9 of material, transmitting UV-irradiation, filled by a liquid heat transfer agent 11. A width of a gap between the pipe 9 and the lamp 8 and absorption index of the heat transfer agent 11 are mutually connected by designed relations. The holder 7 may be inclined by an adjustable angle due to using the articulation joint 5. The removable reflector 10 provides preferable direction of UV-irradiation distribution onto a surface, being sterilized. EFFECT: enhanced quality of disinfecting process without using of disinfecting solutions and chemical preparations. 4 cl, 4 dwg

Description

 The invention relates to techniques for disinfection and disinfection, in particular to devices for the operational disinfection of air and open surfaces in operating rooms, dressing rooms, clinics, bacteriological laboratories, in shops and industrial premises of enterprises, etc.

 A device for cleaning air using ultraviolet (UV) radiation, comprising a vertical housing with a UV lamp located in its upper part [1]. UV lamp creates a constant bactericidal radiation flux that kills air microorganisms. Air is moved relative to the UV lamp due to convection or active retraction.

 The disadvantages of the known device are low productivity due to the use of a low-intensity source of continuous UV radiation of the line spectrum (low pressure mercury germicidal lamp), and the presence of undesirable side effects associated with prolonged exposure to air of UV radiation, namely the production of high concentrations of ozone and other toxic gases.

 Also known is a device for air disinfection and surface disinfection (sterilizer), which is closest in essence to the proposed one, containing a power and control unit located in a movable housing, a fan and an irradiator with a UV radiation source mounted vertically in the holder and connected to the power supply and management [2].

 Due to the use of powerful mercury UV lamp of continuous operation, the productivity of the known sterilizer is increased, however, it remains clearly insufficient for rapid express disinfection. So, to sterilize a room with dimensions of about 5x7 m, the work of the known sterilizer is necessary for 3 hours while ensuring air circulation. During this time, a significant amount of ozone is accumulated in the room. In addition, in the known sterilizer to reduce the time required for sterilization, provides for the use of an additional air ozonizer.

 Thus, the well-known sterilizer can be used only in those rooms where people have been absent for a long time (several hours), necessary for sterilization and subsequent reduction of the concentration of ozone and other toxic gases to a safe level. In addition, the presence of mercury vapor in the lamps of a known sterilizer poses a potential risk of mercury poisoning in the event of any negligence or accident.

≥ 1 где U - напряжение заряда накопительного конденсатора, В;
C - емкость накопительного конденсатора, Ф;
L - индуктивность разрядного контура, Гн;
d - внутренний диаметр газоразрядной лампы, м;
l - расстояние между электродами газоразрядной лампы, м;
А = 10⁹ Вт/м² - постоянный коэффициент.To eliminate these shortcomings in the device for air disinfection and disinfection of surfaces, containing a power and control unit, a fan and an irradiator with a UV radiation source mounted vertically in the holder and connected to the power and control unit, the UV radiation source is made in the form pulsed discharge lamp, the power supply and control unit contains a constant voltage source, a storage capacitor connected to a constant voltage source, and an impu of ignition pulses, moreover, the pulsed discharge lamp and the storage capacitor are interconnected so as to form a discharge circuit, the ignition pulse generator is inductively coupled to the discharge circuit, and the parameters of the discharge circuit are interconnected by the ratio:

≥ 1 where U is the charge voltage of the storage capacitor, V;
C is the capacity of the storage capacitor, f;
L is the inductance of the discharge circuit, GN;
d is the inner diameter of the discharge lamp, m;
l is the distance between the electrodes of the discharge lamp, m;
A = 10 ⁹ W / m ² is a constant coefficient.

The source of UV radiation can be equipped with a cooling device in the form of a coaxial tube made of a material transparent to UV radiation, the cavity between the inner wall of the tube and the radiation source is filled with liquid refrigerant, and the following relationships are true:
Δ ˙ χ ₁₉₀ > 0.5,
Δ ˙ χ ₂₂₀ <0.2, where Δ is the thickness of the gap between the inner wall of the tube and the source of UV radiation;
χ ₁₉₀ , χ ₂₂₀ is the natural absorption coefficient of the refrigerant at wavelengths λ ≅ 190 nm and λ ≥220 nm, respectively.

 The holder of the UV radiation source can be made with adjustable tilt.

 The irradiator can be equipped with a removable reflector.

 In FIG. 1 schematically shows the design of a device for disinfecting and disinfecting surfaces; figure 2 is a section aa in figure 1 on an enlarged scale; figure 3 is a block diagram of a power supply and control; figure 4 is an embodiment of a power supply and control unit.

 The device comprises a movable housing 1, in which a power and control unit 2, a fan 3 and a pump 4 are placed. On the upper cover of the housing 1, an irradiator 6 is fixed with a hinge 5, which consists of a holder 7, a UV radiation source 8, a coaxial tube 9 of UV-transparent material (for example, quartz) and a removable reflector 10. In the gap of thickness Δ between the source 8 and the tube 9 is liquid refrigerant 11 (for example, distilled water).

 As a source of UV radiation 8, a pulsed discharge lamp is used, filled with an inert gas (xenon), connected to a power and control unit 2 (FIGS. 3 and 4). The cavity between the source 8 and the tube 9 is connected by flexible hoses (not shown) to the pump 4.

 The power supply and control unit 2 contains a constant voltage source 12, a storage capacitor 13, an ignition pulse generator 14, and a control circuit 15. A storage capacitor 13 is connected to a constant voltage source 12. The pulse discharge lamp 8 and the storage capacitor 13 form a discharge circuit, which is inductively coupled the ignition pulse generator 14. Such communication can be carried out, for example, using a pulse transformer 16 or using a special electrode 17 near the lamp 8 (figure 4).

 As a source of constant voltage 12, a high-voltage rectifier with a voltage of 2-5 kV is used. The ignition pulse generator 14 is a pulse shaper with an amplitude of 20-40 kV, a duration of 0.1-1.0 μs and a repetition rate of 0.5-5 Hz. The control circuit 15 contains (not shown) a common network switch, a voltage value switch at the output of the constant voltage source 12, a voltage indicator on the storage capacitor 13, a pulse counter, a pulse number switch and a remote control.

 The device operates as follows.

 In the use mode for air disinfection, the removable reflector 10 is removed, the holder 7 with the lamp 8 is installed vertically. The device is placed in a room in which air must be disinfected. Using the controls of the control circuit 15, the operating mode of the pulsed gas discharge lamp 8 is set, which is determined by the voltage of the storage capacitor 13 and the number of pulses, based on the total energy dose of UV radiation required for this room. Then the operator leaves the treated room and transfers the unit to the radiation mode from the remote control panel. By this command, the control circuit 15 includes a constant voltage source 12, which charges the storage capacitor 13. Upon reaching a predetermined voltage value on the storage capacitor 13, the control circuit 15 includes an ignition pulse generator 14 that generates a high voltage ignition pulse. Due to the inductive coupling of the ignition pulse generator 14 with the discharge circuit, an electric discharge of the capacitor 13 is initiated through the gas discharge lamp 8.

A powerful pulsed electric discharge in an inert gas filling the lamp 8, leads to its intense heating and ionization. The resulting plasma with temperatures 10,000-15,000 K is a high-intensity (power density UV radiation exceeds 10 ^8th. W / m ²⁾ a source of broadband radiation, a substantial proportion of which falls on the UV spectral region (wavelengths shorter than 400 nm). Such discharge modes in the lamp 8 are realized if the parameters of the discharge circuit satisfy the design ratio given in claim 1.

 The radiation flux from the lamp 8 passes through a liquid refrigerant 11, a quartz tube 9 and spreads in all directions, carrying out a bactericidal effect.

 Then the process is repeated as many times as the number of pulses will be generated by the control circuit 15.

 Liquid refrigerant 11, located in a gap of thickness Δ (Fig. 2) between the flash lamp 8 and quartz tube 9, simultaneously performs two functions: cooling the lamp 8 itself to ensure the discharge parameters in the lamp remains constant and spectral selection of broadband UV radiation to reduce residual unwanted side effects (ozone formation). For cooling, the cavity of the tube 9 can be connected by flexible hoses to a pump 4, which carries out the pumping of refrigerant. To perform spectral selection, the optical parameters of the refrigerant (natural absorption coefficient χ and gap thickness Δ) are selected in accordance with the calculated ratios given in paragraph 2 of the claims.

 Such a choice of parameters provides suppression of the ozone-forming part of the UV-radiation spectrum (wavelength shorter than 210 nm) and a sufficiently high transmittance within the bactericidal part (spectral section 220-320 nm).

 Fan 3 helps to cool the lamp 8 and circulates the air in the room, moving new portions of air closer to the lamp 8, where the intensity of UV radiation is higher.

 In the mode of using the device for dry (without the use of any chemicals and solutions) disinfection of surfaces in the irradiator 6, a reflector 10 is installed, which creates mainly the direction of propagation of UV radiation towards the surface to be treated. For this, the entire irradiator 6 tilts in any direction on the hinge 5. Otherwise, the operation of the device in this mode does not differ from the operation in the air disinfection mode.

 The technical efficiency of the proposed device consists in a significant reduction in processing time (several minutes), which allows the installation to be used for express disinfection, as well as in eliminating undesirable side effects associated with the formation of toxic gases, in improving safety (there is no mercury) and ease of use.

 These advantages in relation to all known devices of the same purpose are due to a significant reduction in the total energy dose necessary to achieve complete sterilization or an acceptable level of bacterial air pollution in the treated rooms or on irradiated surfaces.

 The reduction in the total energy dose when using high-intensity pulsed UV radiation of a continuous spectrum instead of the low-intensity continuous UV radiation of a linear spectrum characteristic of known devices is associated with a number of factors.

 1) With high-intensity UV exposure, the rate of suppression of pathogenic microflora in air or on the surface significantly exceeds its growth rate due to intrinsic reproduction and external seeding. With low-intensity UV exposure, a reverse reaction is possible and a useful effect may be absent even with a very long exposure time (or energy doses).

 2) With prolonged low-intensity irradiation, microorganisms adapt to UV radiation and, as a result, their sensitivity to UV radiation decreases. Moreover, it is known that in some cases, low-intensity UV radiation stimulates the growth and reproduction of microorganisms.

 3) With broadband irradiation (continuous spectrum), compared with the influence of monoenergetic radiation (i.e., radiation with a linear spectrum), the possibilities of adaptation of living matter to UV radiation are significantly reduced, which is associated with a multi-channel destructive effect on photon biomolecules with a wide energy spectrum.

 4) Different types of microorganisms have different spectral characteristics of bactericidal efficiency and optical transmission, therefore, broadband UV radiation in case of strong bacterial contamination of air or surfaces will on average have a large penetration depth and lower threshold energy doses required for sterilization.

 The reduction of the threshold energy doses of exposure during pulsed irradiation of air or surfaces with continuous spectrum radiation and the high-intensity nature of the irradiation lead to the fact that the processing time required to sterilize or achieve an acceptable level of bacterial contamination of air or surfaces is significantly reduced (up to several minutes). At the same time, the manifestation of negative side effects (production of ozone, etc.) is also reduced. An additional reduction in negative side effects is provided by the implementation of the device according to claim 2.

In a specific embodiment, the installation has a mass of 40 kg, the dimensions of the mobile housing 400x500x600 mm, and the dimensions of the irradiator 100x200x1000 mm. With a consumed electric power of not more than 2 kW, the installation creates a power density of pulsed UV radiation at a distance of 1 m from the irradiator more than 100 kW / m ² , which allows disinfecting air in a room with a volume of 100 m ³ for 5 minutes. It takes about 40 s to disinfect a surface of 1 m ² at a distance of 1 m from the irradiator.

 Such capabilities of the proposed device can be successfully used for rapid disinfection of air in various rooms and for dry express disinfection of surfaces of objects.

Claims (4)

1. DEVICE FOR DISINFECTING AIR AND SURFACES, comprising a housing, a power supply and control unit with an ignition system, a fan installed in the housing, an irradiator with an ultraviolet radiation source mounted vertically in the holder and connected to the power supply and control unit, characterized in that the ultraviolet source radiation is made in the form of a pulsed discharge lamp, the power supply and control unit is equipped with a secondary constant voltage source and storage capacitor, the ignition system is made it is not in the form of an ignition pulse generator, while the storage capacitor and gas discharge lamp are connected to a secondary constant voltage source so as to form a discharge circuit, the ignition pulse generator is inductively coupled to the discharge circuit, and the circuit parameters are determined by the relation

where U is the voltage of the storage capacitor, V;
C is the capacity of the storage capacitor, f;
L is the inductance of the discharge circuit, GN;
d is the inner diameter of the discharge lamp, m;
l is the distance between the electrodes of the discharge lamp;
A-10 ⁹ W / m ² is a constant coefficient. 2. The device according to claim 1, characterized in that the source of ultraviolet radiation is equipped with a cooling system made in the form of a tube made of a material transparent to ultraviolet radiation, in which the radiation source is coaxially located, wherein the cavity between the walls of the tube and the source is filled with liquid refrigerant, refrigerant substance corresponds to the following ratios:

where Δ is the thickness of the gap between the inner wall of the tube and the radiation source, m;
c ₁₉₀ , χ ₂₂₀ - natural indicator of the absorption of the refrigerant ultraviolet radiation at a wavelength of λ ≅ 190 nm and l ≥ 220 nm, respectively, m  3. The device according to claim 1, characterized in that the holder is configured to change the angle of inclination.  4. The device according to claim 1, characterized in that the emitter is equipped with a removable reflector.

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