Fluid sterilization device

Abstract

We provide a fluid sterilization device capable of killing and inactivating various bacteria and viruses. [Solution] The fluid sterilization device has a plurality of light-emitting elements 4 that emit ultraviolet light, and a flow channel space through which fluid flows and into which the ultraviolet light emitted by the light-emitting elements 4 is incident. The peak wavelengths of each light-emitting element are not the same, and the composite spectrum obtained by adding the spectra of each light-emitting element has one peak and a half-width of 20 nm or more.

Description

Technical Field

[0001] The present invention relates to a fluid sterilization device.

Background Art

[0002] There is known a fluid sterilization device that sterilizes and inactivates bacteria and viruses in running water by irradiating ultraviolet light. A mercury lamp is widely used as a light source. Since the mercury lamp uses mercury, there is a problem of a large environmental load. In addition, when using a mercury lamp, there is also a problem that the fluid sterilization device becomes large. Therefore, the replacement from a mercury lamp to a light-emitting element that emits ultraviolet light is in progress.

[0003] The wavelengths capable of efficiently sterilizing and inactivating bacteria and viruses vary depending on the types of bacteria and viruses. Since the mercury lamp cannot change its wavelength and has a sharp spectrum shape, it cannot cope with various types of bacteria and viruses. On the other hand, although the emission spectrum of the light-emitting element that emits ultraviolet light is wider than that of the mercury lamp, its half-value width is about 10 nm and is narrow (see Patent Documents 1 and 2). Therefore, simply using a light-emitting element that emits ultraviolet light may not be able to cope with the sterilization and inactivation of various types of bacteria and viruses.

[0004] Patent Document 2 describes using two ultraviolet LEDs (wavelengths 265 nm and 280 nm) with different emission wavelengths in a fluid sterilization device so that the two spectra overlap. Thereby, even when the types of bacteria and viruses are unknown, efficient sterilization and inactivation can be achieved.

[0005] Further, Patent Document 3 describes an inspection device for inspecting photosensitivity of the skin, and using a plurality of light-emitting elements that emit ultraviolet light with different emission wavelengths so that the combined spectrum thereof is close to the spectrum of a fluorescent lamp.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] However, when using two ultraviolet light-emitting elements with different emission wavelengths, as in Patent Document 2, the emission spectrum may have two peaks, potentially creating a dip between them. Because wavelengths with low light intensity are present, the sterilization and inactivation effects may be reduced for some types of bacteria and viruses.

[0008] This invention was made in view of the above background, and aims to provide a fluid sterilization device capable of killing or inactivating various bacteria and viruses. [Means for solving the problem]

[0009] One aspect of the present invention is, Multiple light-emitting elements that emit ultraviolet light, It has a space through which a fluid flows and a channel space into which ultraviolet light emitted by the light-emitting element is incident, The composite spectrum obtained by summing the spectra of each of the aforementioned light-emitting elements has a shape with one peak and a full width at half maximum of 20 nm or more, in the fluid sterilization device. [Effects of the Invention]

[0010] In the above embodiment, the composite spectrum obtained by summing the spectra of each light-emitting element has one peak and a full width at half maximum of 20 nm or more. By setting it in this way, various types of bacteria and viruses can be killed or inactivated.

[0011] As described above, according to the above embodiment, a fluid sterilization device capable of sterilizing and inactivating various bacteria and viruses can be provided. [Brief explanation of the drawing]

[0012] [Figure 1] A cross-sectional view showing the configuration of a fluid sterilization apparatus in Embodiment 1, wherein the cross-sectional view is taken in a plane including the axis of the flow channel pipe. [Figure 2] A figure showing an example of the spectrum of a light-emitting element. [Figure 3] A diagram showing the variation in the emission spectrum of a light-emitting element. [Figure 4] A figure showing an example of a synthesized spectrum. [Figure 5] A cross-sectional view showing the configuration of a fluid sterilization apparatus in Embodiment 1, wherein the cross-sectional view is taken in a plane including the axis of the flow channel pipe. [Modes for carrying out the invention]

[0013] The fluid sterilization device comprises multiple light-emitting elements that emit ultraviolet light, and a fluid channel space through which the ultraviolet light emitted by the light-emitting elements enters. The composite spectrum obtained by summing the spectra of each light-emitting element has a single peak and a half-width of 20 nm or more.

[0014] In the above-described fluid sterilization apparatus, the peak wavelength of the synthesized spectrum may be between 260 nm and 285 nm. This allows for more efficient sterilization and inactivation of bacteria and viruses.

[0015] In the above-described fluid sterilization apparatus, the full width at half maximum of the synthesized spectrum may be between 25 nm and 50 nm. This allows for more efficient sterilization and inactivation of a wider variety of bacteria and viruses.

[0016] In the above-described fluid sterilization apparatus, the larger of the two wavelengths at which the peak value of the composite spectrum is halved may be between 270 nm and 290 nm, and the smaller wavelength may be between 250 nm and 270 nm. This allows for more efficient sterilization and inactivation of bacteria and viruses.

[0017] In the above fluid sterilization device, the maximum value among the peak wavelengths of each light-emitting element may be 270 nm or more and 290 nm or less, and the minimum value may be 250 nm or more and 270 nm or less.

[0018] In the above fluid sterilization device, the average of the peak wavelengths of the light-emitting elements may be 260 nm or more and 285 nm or less.

[0019] In the above fluid sterilization device, the full width at half maximum of each light-emitting element may be 10 to 15 nm.

[0020] In the above fluid sterilization device, the peak of the light intensity of each light-emitting element may be within the range of -10% to +10% with respect to the average of the peaks of the light intensities of the plurality of light-emitting elements. Various types of bacteria and viruses can be sterilized and inactivated more efficiently.

[0021] In the above fluid sterilization device, the flow path space may be cylindrical, and the plurality of light-emitting elements may be arranged in a linear direction parallel to the axial direction of the cylinder. Thereby, various types of bacteria and viruses can be sterilized and inactivated more efficiently.

[0022] In the above fluid sterilization device, the flow path space may be cylindrical, and the plurality of the light-emitting elements may be arranged on the outer peripheral bottom surface of the cylinder. A large amount of fluid can be sterilized and inactivated at once.

[0023] (Embodiment 1) FIG. 1 is a cross-sectional view showing the configuration of the fluid sterilization device in Embodiment 1, and is a cross-section in a plane including the axis of the flow path tube. As shown in FIG. 1, the fluid sterilization device in Embodiment 1 has a flow path tube 1, an inlet 2, an outlet 3, and a plurality of light-emitting elements 4.

[0024] The flow channel tube 1 is a cylindrical tube made of quartz and is a component that forms a flow channel space for the liquid to be sterilized. The flow channel space is a cylindrical space inside the flow channel tube 1. The material of the flow channel tube 1 is not limited to quartz; any material that transmits ultraviolet light and has a low absorption rate is acceptable. For example, sapphire, ultraviolet-transmitting glass, fluororesin, acrylic resin, etc., may be used. The fluid to be sterilized may be a gas or a liquid, and as long as it has fluidity, it may be a mixture of gas and liquid, a mixture of gas and powdered solid, etc. In the case of a liquid, for example, it may be water, oil, alcohol, or a solvent using these as a solvent.

[0025] An inlet 2 is provided on the side wall of one end of the flow channel pipe 1 for introducing fluid into the flow channel pipe 1. An outlet 3 is provided on the side wall of the other end of the flow channel pipe 1 for discharging the fluid inside the flow channel pipe 1 to the outside.

[0026] The light-emitting element 4 is positioned on the outer surface of the flow channel tube 1, and is positioned so that the direction of ultraviolet light emission is toward the central axis of the flow channel tube 1. The light-emitting element 4 may be mounted on a submount to constitute a light-emitting device. Alternatively, the light-emitting device may be mounted on a drive circuit board. Alternatively, the light-emitting element 4 may be directly mounted on the drive circuit board.

[0027] In Embodiment 1, the light-emitting elements 4 are arranged on the outer surface of the flow channel 1, but they may also be arranged on the outer bottom surface of the flow channel 1, or on both the outer surface and the outer bottom surface. Furthermore, if they are arranged on the outer bottom surface, they may be on both the inlet 2 side and the outlet 3 side, or on just one side. In short, any arrangement is acceptable as long as the ultraviolet light emitted by the multiple light-emitting elements 4 is directed onto the fluid.

[0028] Figure 2 shows an example of the emission spectrum of the light-emitting element 4. In Figure 2, the light intensity is normalized with the light intensity at the peak wavelength set to 1. Figure 3 shows the variation in the emission spectrum of the light-emitting element 4. In Figure 3, the average of the light intensities of multiple light-emitting elements 4 is normalized to 1.

[0029] The full width at half maximum (FWHM) W1 of the emission spectrum of each light-emitting element 4 is 10-15 nm. The variation in FWHM W1 (the difference between the maximum and minimum FWHM W1 of each light-emitting element 4) is approximately 1-5 nm. The peak wavelength of each light-emitting element 4 is set to produce the combined spectrum described later.

[0030] The peak wavelengths of each light-emitting element 4 are not all the same, but vary. The variation in the peak wavelengths of each light-emitting element 4 (the difference between the maximum and minimum peak wavelengths of each light-emitting element 4) is approximately 10-20 nm. The maximum peak wavelength of each light-emitting element 4 should ideally be 270-290 nm. The minimum peak wavelength of each light-emitting element 4 should ideally be 250-270 nm. The average of the peak wavelengths of multiple light-emitting elements should ideally be 260-285 nm.

[0031] Furthermore, as shown in Figure 3, it is preferable that the peak intensity of each light-emitting element 4 be within the range of -10% to +10% of the average of the peak intensities of the multiple light-emitting elements. By doing so, various types of bacteria and viruses can be killed or inactivated more efficiently.

[0032] The number of light-emitting elements 4 is arbitrary, as long as the combined spectrum described later can be achieved. For example, 5 to 500 elements. Also, the peak wavelengths of all light-emitting elements 4 do not need to be different; there may be light-emitting elements 4 with the same peak wavelength, as long as the combined spectrum described later can be achieved.

[0033] Furthermore, the arrangement pattern of the light-emitting elements 4 can be arbitrary; they may be arranged linearly on the outer surface in a direction parallel to the axis, or they may be arranged both parallel to the axis and in the circumferential direction. Also, the arrangement does not need to be equally spaced.

[0034] Furthermore, it is not necessary for the irradiation areas of the ultraviolet light emitted by each light-emitting element 4 to overlap. It is sufficient that the system is configured so that the ultraviolet light emitted by each light-emitting element 4 is irradiated during the time the fluid flows from the inlet 2 into the flow channel 1 and is discharged from the outlet 3. In terms of sterilizing and inactivating various types of bacteria and viruses, whether the irradiation areas overlap or not does not have a significant impact. For example, in Embodiment 1, the irradiation area of ​​the ultraviolet light emitted by the light-emitting element 4 closest to the inlet 2 does not overlap with the irradiation area of ​​the light-emitting element 4 closest to the outlet 3.

[0035] The combined spectrum, obtained by summing the ultraviolet light emission spectra emitted by each light-emitting element 4, has a single peak and a half-width W2 of 20 nm or more. An example of the combined spectrum is shown in Figure 4. The combined spectrum is simply the sum of the individual emission spectra in their unnormalized state. In Figure 4, the combined spectrum is shown as a solid line, and the peak intensity of the combined spectrum is normalized to 1. Also in Figure 4, an example of each emission spectrum being added is shown as a dotted line.

[0036] The full width at half maximum (FMAX) W2 of such a composite spectrum is related to the variety of bacteria and viruses that can be killed or inactivated while the fluid is flowing through the channel space. Furthermore, the light intensity of the composite spectrum is related to the sterilization efficiency. Therefore, by determining the composite spectrum, it is possible to evaluate the number of bacteria and viruses that can be killed or inactivated, as well as the sterilization efficiency.

[0037] Furthermore, by setting the peak wavelength of each light-emitting element 4 such that the combined spectrum has one peak and a full width at half maximum W2 of 20 nm or more, various types of bacteria and viruses can be efficiently killed or inactivated.

[0038] The first reason is that there is only one peak and no dips in the spectrum. When dips exist in the spectrum, the light intensity at wavelengths near those dips is low, making it difficult to efficiently kill bacteria and viruses that can be killed or inactivated at those wavelengths. However, if there are no dips in the spectrum, there is no decrease in light intensity at those wavelengths, thus suppressing the decrease in sterilization efficiency.

[0039] Furthermore, because the synthesized spectrum has only one peak, sterilization and inactivation can be performed most efficiently at the target peak wavelength. In addition, high light intensity is also observed at wavelengths surrounding that peak wavelength, making it possible to sterilize and inactivate bacteria and viruses that are difficult to sterilize or inactivate at the target peak wavelength. In this way, by having only one peak in the synthesized spectrum, it becomes easier to achieve both improved sterilization efficiency and an increase in the number of types of bacteria and viruses that can be sterilized or inactivated.

[0040] Secondly, although the optimal wavelength for sterilization and inactivation varies depending on the type of bacteria or virus, the synthetic spectrum has a full width at half maximum (W2) of 20 nm or more, allowing for efficient sterilization and inactivation of various types of bacteria and viruses.

[0041] The full width at half maximum (FWHM) W2 of the composite spectrum is preferably set to 25-50 nm. Setting it to 25 nm or higher allows for a greater variety of bacteria and viruses that can be sterilized or inactivated. Furthermore, to broaden the FWHM W2, it is necessary to prepare multiple light-emitting elements 4 with different wavelength peaks, and the difference between the maximum and minimum peak wavelengths of the light-emitting elements 4 must be large. If the FWHM W2 is 50 nm or less, it is possible to sufficiently increase the variety of bacteria and viruses that can be sterilized or inactivated while sufficiently reducing the number of types of light-emitting elements 4.

[0042] The peak wavelength of the synthesized spectrum is preferably 260-285 nm. Within this range, bacteria and viruses can be more efficiently killed or inactivated.

[0043] Furthermore, in the composite spectrum, the larger of the two wavelengths at which the peak value is halved is preferably 270-290 nm. Also, the smaller of the two wavelengths at which the peak value is halved is preferably 250-270 nm.

[0044] Furthermore, as shown in Figure 3, it is preferable that the peak wavelength of each light-emitting element 4 is within the range of -10% to +10% of the peak wavelength in the composite spectrum. By setting it within this range, various types of bacteria and viruses can be more efficiently sterilized and inactivated.

[0045] As described above, the fluid sterilization apparatus in Embodiment 1 can sterilize and inactivate various types of bacteria and viruses.

[0046] In Embodiment 1, a cylindrical flow channel tube 1 is used, and the flow channel space through which the fluid flows and into which ultraviolet light emitted by the light-emitting element 4 enters is cylindrical. However, the shape of the flow channel space is not limited to this and can be any shape. For example, the flow channel space may be rectangular or spherical.

[0047] Furthermore, in Embodiment 1, the light-emitting element 4 is placed outside the flow channel 1, and ultraviolet light is transmitted through the flow channel 1 to irradiate the fluid, but this is not the only possible configuration. Any configuration in which ultraviolet light is irradiated into the flow channel space is acceptable. For example, a hole may be provided in the flow channel 1, and a light source unit including the light-emitting element 4 may be provided to fill the hole, thereby irradiating the fluid with ultraviolet light without transmitting it through the flow channel 1.

[0048] Figure 5 is a cross-sectional view showing the configuration of a fluid sterilization device in a modified form of Embodiment 1, and is a cross-sectional view in a plane including the axis of the flow channel pipe. As shown in Figure 5, the fluid sterilization device in the modified form of Embodiment 1 has a flow channel pipe 11, an inlet 12, an outlet 13, and a plurality of light-emitting elements 14.

[0049] The flow channel pipe 11 has the same configuration as the flow channel pipe 1 in Embodiment 1, except for the diameter of the pipe. Also, similar to Embodiment 1, an inlet 12 for introducing fluid into the flow channel pipe 11 is provided on the side wall of one end of the flow channel pipe 11. An outlet 13 for discharging the fluid inside the flow channel pipe 11 to the outside is provided on the side wall of the other end of the flow channel pipe 11.

[0050] The light-emitting elements 14 are the same as those used in Embodiment 1. Multiple light-emitting elements 14 are arranged on the outer bottom surface of the flow channel tube 11 on the inlet 12 side. The light-emitting elements 14 are also arranged so that the direction of ultraviolet light emitted from them is parallel to the axial direction of the flow channel tube 11. The number and arrangement pattern of the light-emitting elements 14 are the same as in Embodiment 1. The diameter of the flow channel tube 11 is set to be wide enough to accommodate multiple light-emitting elements 14 on the outer bottom surface.

[0051] In the fluid sterilization device in the modified form of Embodiment 1, the direction of ultraviolet light emitted by the light-emitting element 14 is parallel to the axial direction of the flow channel 11, so that the fluid can be efficiently sterilized and inactivated. Furthermore, since the emission spectrum of each light-emitting element 14 is set in the same way as in Embodiment 1, various types of bacteria and viruses can be sterilized and inactivated more efficiently.

[0052] The fluid sterilization device in the modified form of Embodiment 1 shown in Figure 5 is suitable for sterilizing and inactivating large quantities of fluid at once. Therefore, the fluid sterilization device in the modified form of Embodiment 1 is suitable for use in large-scale treatment facilities such as water treatment plants. [Explanation of symbols]

[0053] 1, 11: Flow channel 2, 12: Inlet 3, 13: Outlet 4, 14: Light-emitting element

Claims

1. Multiple light-emitting elements that emit ultraviolet light, It has a space through which a fluid flows and a channel space into which ultraviolet light emitted by the light-emitting element is incident, The peak wavelengths of each of the aforementioned light-emitting elements are not the same. A fluid sterilization device in which the combined spectrum obtained by summing the spectra of each of the aforementioned light-emitting elements has one peak and a half-width of 20 nm or more.

2. The fluid sterilization apparatus according to claim 1, wherein the peak wavelength of the composite spectrum is 260 nm or more and 285 nm or less.

3. The fluid sterilization apparatus according to claim 1, wherein the full width at half maximum of the synthesized spectrum is 25 nm or more and 50 nm or less.

4. The fluid sterilization apparatus according to claim 1, wherein the larger of the two wavelengths at which the peak value of the composite spectrum is halved is 270 nm or more and 290 nm or less, and the smaller wavelength is 250 nm or more and 270 nm or less.

5. The fluid sterilization apparatus according to any one of claims 1 to 4, wherein the maximum value of the peak wavelength of each light-emitting element is 270 nm or more and 290 nm or less, and the minimum value is 250 nm or more and 270 nm or less.

6. The fluid sterilization apparatus according to any one of claims 1 to 4, wherein the average of the peak wavelengths of the plurality of light-emitting elements is 260 nm or more and 285 nm or less.

7. The fluid sterilization apparatus according to any one of claims 1 to 4, wherein the half-width of each light-emitting element is 10 nm or more and 15 nm or less.

8. The fluid sterilization apparatus according to any one of claims 1 to 4, wherein the peak of the light intensity of each of the light-emitting elements is within a range of -10% to +10% of the average of the peaks of the light intensity of the plurality of light-emitting elements.

9. The aforementioned flow channel space is cylindrical, The fluid sterilization apparatus according to any one of claims 1 to 4, wherein the plurality of light-emitting elements are arranged in a linear direction parallel to the axial direction of the cylinder.

10. The aforementioned flow channel space is cylindrical, The fluid sterilization apparatus according to any one of claims 1 to 4, wherein the plurality of light-emitting elements are arranged on the outer bottom surface of the cylinder.

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