TWI890919B - Fluid sterilization device - Google Patents

Abstract

The present invention provides a fluid sterilization device that can achieve larger containers and reduce manufacturing costs. The fluid sterilization device in one embodiment includes: a container having a space within which a fluid to be processed can circulate and containing metal; a light source capable of irradiating ultraviolet light into the space within the container; and at least one first reflector or second reflector disposed on the inner surface of the container. The first reflector is sheet-shaped and contains a fluororesin. The second reflector is film-shaped and contains a silicone resin.

Description

Fluid sterilization device

An embodiment of the present invention relates to a fluid sterilization device.

There are fluid sterilization devices that sterilize fluids such as water by irradiating them with ultraviolet rays. For example, a fluid sterilization device has been proposed that includes a container in which the fluid flows and a light source disposed at an end of the container for irradiating the interior of the container with ultraviolet rays.

In this case, the inner surface of the container contacts the fluid being processed and is simultaneously struck by a portion of the ultraviolet light irradiated from the light source. Therefore, the container is formed of a material that is resistant to both the fluid being processed and the ultraviolet light. For example, a fluid sterilization device has been proposed that includes a container made of quartz glass or a container made of a fluororesin such as polytetrafluoroethylene (PTFE).

In recent years, there has been a desire to increase the processing flow rate, leading to a need for larger fluid sterilization devices and, consequently, larger containers. However, containers made of quartz glass or fluororesin are expensive to manufacture, and increasing the size of the container incurs even greater costs. Consequently, increasing the processing flow rate of fluid sterilization devices has been difficult. Therefore, there is a desire to develop a fluid sterilization device that can achieve both larger containers and reduced manufacturing costs. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2018-122262 [Patent Document 2] Japanese Patent Publication No. 2018-118201

[Problem to be Solved by the Invention] The present invention aims to provide a fluid sterilization device that can achieve larger containers and reduce manufacturing costs. [Technical Solution]

A fluid sterilization device according to an embodiment includes: a container containing a metal having a space within which a fluid to be treated can flow; a light source capable of irradiating ultraviolet light into the space within the container; and at least one first reflector or second reflector disposed on the inner surface of the container. The first reflector is sheet-shaped and contains a fluororesin. The second reflector is film-shaped and contains a silicone resin. [Effects of the Invention]

According to the embodiment of the present invention, a fluid sterilization device can be provided that can realize the enlargement of the container and reduce the manufacturing cost.

Hereinafter, embodiments will be described with reference to the accompanying drawings. In the drawings, identical components are denoted by identical reference numerals, and detailed descriptions thereof will be omitted as appropriate.

Figure 1 is a schematic perspective view of a fluid sterilization device 1 according to this embodiment. Figure 2 is a schematic cross-sectional view of the fluid sterilization device 1 taken along line A-A in Figure 1 . As shown in Figure 1 , the fluid sterilization device 1 includes, for example, a container 2, a window 3, a light source 4, and a reflector 5 (equivalent to an example of a first reflector).

Container 2 has a space within it (hereinafter referred to as the internal space) through which the fluid 301a being processed circulates. Container 2 may, for example, be elongated in one direction. Container 2 may be cylindrical, for example. For example, one end of container 2 may be open, while the other end may be closed. A plate may be welded to the other end of container 2, or the plate may be removably attached via a sealing member. Container 2 may, for example, be a closed cylindrical tube at one end.

Container 2 can be formed from a metal that is resistant to the fluid 301a being processed. For example, container 2 can be formed from stainless steel. Alternatively, for reasons of weight reduction, container 2 can be formed from titanium or aluminum. Furthermore, for reasons of cost reduction and corrosion resistance, container 2 can be formed from iron or aluminum, and surface treatments such as plating or alumina coating can be applied.

A supply pipe 21 and a discharge pipe 22 can be installed in the container 2. The supply pipe 21 is tubular and installed on the outer surface of the container 2. The internal hole of the supply pipe 21 is connected to the interior space of the container 2. The supply pipe 21 is connected to the source of the fluid 301a being processed, for example, via piping. The source of the fluid 301a can be, for example, a pump that pressurizes the fluid 301a. The supply pipe 21 can be installed, for example, near the end of the container 2. The supply pipe 21 shown in Figure 1 is installed near the end of the container 2 on the side opposite the window 3.

The discharge pipe 22 is tubular and installed on the outer surface of the container 2. The internal hole of the discharge pipe 22 is connected to the interior space of the container 2. The discharge pipe 22 is connected, for example, via piping to a tank or cleaning device that supplies the sterilized fluid 301b. The discharge pipe 22 can be installed, for example, near the end of the container 2 opposite the side where the supply pipe 21 is installed. The discharge pipe 22 shown in Figure 1 is installed near the end of the container 2 on the window 3 side. Also, as shown in Figure 1, the supply pipe 21 and the discharge pipe 22 are preferably installed at positions that are symmetrical about the center of the interior space of the container 2.

When the supply pipe 21 and the discharge pipe 22 are positioned as described above, the fluid 301a supplied from the supply pipe 21 into the interior of the container 2 flows toward the window 3 where the ultraviolet rays are incident. Consequently, the supplied fluid 301a is efficiently sterilized by the ultraviolet rays. Furthermore, the flow within the interior of the container 2 is directed along the central axis of the container 2, thereby preventing the sterilized fluid 301b from stagnating within the interior of the container 2.

In addition, if the supply pipe 21 and the discharge pipe 22 are arranged at positions symmetrical with respect to the center of the internal space of the container 2, the fluid 301a can be sterilized more efficiently, and the sterilized fluid 301b can be further prevented from stagnation in the internal space of the container 2.

Furthermore, the installation positions of the supply pipe 21 and the exhaust pipe 22 are not limited to the positions exemplified above. For example, the supply pipe 21 may be installed on the surface facing the window 3.

Window 3 is plate-shaped and is provided at one end of container 2 in a liquid-tight manner. Window 3 can be removably attached to the end of container 2, for example, via a sealing member. Window 3 blocks the opening at the end of container 2. The surface of window 3 facing container 2 is exposed to the interior of container 2. Window 3 is formed of a material that is transmissive to ultraviolet light and resistant to both ultraviolet light and fluid 301a.

For example, window 3 can be formed from quartz glass, silicone resin, fluororesin, or the like. As described later, ultraviolet light with a peak wavelength of 290 nm or less is irradiated from light source 4 (light-emitting element 41). Therefore, window 3 is preferably formed from quartz glass, which has a high transmittance for ultraviolet light with a peak wavelength of 290 nm or less.

Alternatively, an anti-reflection film may be provided on the surface of the window 3 on the light source 4 side. Providing an anti-reflection film can prevent the ultraviolet light emitted from the light source 4 from being reflected by the window 3 and thus less likely to reach the fluid 301a. In other words, the utilization efficiency of the ultraviolet light emitted from the light source 4 can be improved.

Alternatively, an antifouling film may be provided on the surface of window 3 on the container 2 side. For example, unpurified fluids such as seawater and well water contain foreign matter such as sand, microbial remains, and inorganic salts. Furthermore, even artificially purified fluids sometimes contain inorganic salts. If foreign matter in fluid 301a adheres to window 3 or precipitates, it becomes difficult for the ultraviolet light irradiated by light source 4 to pass through window 3. The provision of an antifouling film can inhibit foreign matter from adhering to window 3 or precipitating. This can maintain the sterilization effect or reduce the need for maintenance.

Light source 4 irradiates ultraviolet light into the interior of container 2. Light source 4 is detachably mounted on the end of container 2 on the side where window 3 is located. Light source 4 comprises, for example, a light-emitting element 41, a substrate 42, and a holder 43. Light-emitting element 41 is mounted on substrate 42 and irradiates ultraviolet light toward window 3. A gap may be provided between light-emitting element 41 and window 3.

At least one light-emitting element 41 may be provided. If multiple light-emitting elements 41 are provided, they may be connected in series. The light-emitting element 41 is not particularly limited as long as it generates ultraviolet light. For example, the light-emitting element 41 may be a light-emitting diode or a laser diode.

The peak wavelength of the ultraviolet light irradiated from the light emitting element 41 is not particularly limited as long as it has a sterilizing effect. In the above case, a peak wavelength of 290 nm or less can enhance the sterilizing effect, and a peak wavelength of 240 nm to 280 nm can further enhance the sterilizing effect.

The substrate 42 is plate-shaped and is placed on the window 3 side of the holder 43. A wiring pattern can be provided on one side of the substrate 42. The material of the substrate 42 is preferably a material resistant to ultraviolet radiation. For example, the substrate 42 can be made of a ceramic such as alumina. Alternatively, the substrate 42 can be a metal plate coated with an inorganic material (a metal core substrate). For example, a metal core substrate can be a metal plate such as aluminum, copper, or stainless steel coated with a ceramic or other material.

If the substrate 42 is made of a material such as ceramic, or if it is a metal core substrate, it can achieve both high resistance to UV radiation and high heat dissipation. High heat dissipation of the substrate 42 prevents the temperature of the light-emitting element 41 from exceeding the maximum junction temperature. This allows for increased power applied to the light-emitting element 41 and increases the flow rate of fluid 301a. Furthermore, even in high-temperature fluids such as hot spring water, the temperature of the light-emitting element 41 is unlikely to exceed the maximum junction temperature. This increases the variety of fluids 301a that can be processed.

The holder 43 can be detachably mounted on the end of the container 2 via a supporting member, for example. While the light-emitting element 41 has a longer lifespan than, for example, a discharge lamp, its luminous efficiency decreases as the lighting time increases. Furthermore, there is a risk that the light-emitting element 41 may malfunction and not illuminate. Removably mounting the holder 43 on the container 2 facilitates replacement of the light-emitting element 41.

The retainer 43 can be, for example, a plate-shaped body. The retainer 43 can be mounted on the end of the container 2 using a fastening member such as a screw, or a supporting member provided on the end of the container 2.

The internal space of the container 2 and the space where the light source 4 is installed are separated by the window 3. Therefore, the light source 4 can be attached and detached even when the fluid 301a is present in the internal space of the container 2. Therefore, the maintainability can be improved.

The holder 43 also functions to dissipate heat generated by the light-emitting element 41 to the outside. Therefore, the holder 43 is preferably formed of a material with high thermal conductivity. For example, the holder 43 can be formed of a metal such as aluminum, copper, or stainless steel. A heat sink may also be provided on the side of the holder 43 opposite the substrate 42 or on a side surface thereof.

A cooling device may also be provided to cool the holder 43. For example, the cooling device may be provided on the side of the holder 43 opposite the substrate 42. For example, the cooling device may be a fan that supplies air to the holder 43. If the holder 43 is equipped with a heat sink, the cooling device may be a fan that supplies air to the heat sink. Alternatively, the cooling device may be provided as a device that supplies liquid to a flow path provided in the holder 43. In other words, the cooling device may be either air-cooled or liquid-cooled.

Furthermore, the cooling device may be omitted depending on the number or heat generation of the light-emitting elements 41, the temperature or flow rate of the fluid 301a, etc. However, if a cooling device is provided, the temperature of the light-emitting element 41 is unlikely to exceed the maximum junction temperature even if the number of light-emitting elements 41 is increased or power is applied.

Furthermore, if a cooling device is provided, even if the temperature of the fluid 301a increases or the flow rate of the hot fluid 301a increases, the temperature of the light-emitting element 41 is unlikely to exceed the maximum junction temperature. Therefore, the range of fluids 301a that can be used can be expanded.

A cover may also be provided to cover the window 3 and light source 4. If a cooling device is installed, a cover may also be provided to cover the window 3, light source 4, and cooling device. The cover can be detachably mounted on the end of the container 2 via a supporting member, for example. The material of the cover is not particularly limited, as long as it possesses a certain degree of rigidity. For example, the cover can be made of metal such as stainless steel. Ventilation holes may also be provided in the cover.

Here, a typical fluid sterilization device is equipped with a container containing quartz glass or a fluororesin such as polytetrafluoroethylene (PTFE). Using a container containing quartz glass or a fluororesin can improve the resistance of the fluid 301a being treated and its resistance to ultraviolet radiation. However, containers containing quartz glass or a fluororesin are expensive to manufacture.

Furthermore, in recent years, there has been a demand for increased processing flow rates. For example, sometimes a processing flow rate of 100 L/min or higher is required. In such cases, increasing the size of the container containing quartz glass or fluororesin would incur additional costs. Therefore, increasing the processing flow rate of fluid sterilization equipment using containers containing quartz glass or fluororesin is difficult.

Therefore, the fluid sterilization apparatus 1 of this embodiment is provided with a metal container 2. The metal container 2 has a lower manufacturing cost than containers made of quartz glass or fluororesin. Therefore, even if the container 2 is enlarged to increase the processing flow rate, the increase in manufacturing cost can be suppressed.

On the other hand, the reflectivity of metal for ultraviolet light is lower than that of fluororesin. Therefore, if ultraviolet light irradiating the interior of container 2 is incident on the inner surface of container 2 containing metal, the amount of ultraviolet light reflected into the interior of container 2 decreases. In other words, the utilization efficiency of the ultraviolet light irradiating the interior of container 2 decreases.

Therefore, the fluid sterilization device 1 of this embodiment is provided with a reflector 5. The reflector 5 is made of a material with a high reflectivity for ultraviolet light. For example, the reflector 5 may be made of a fluororesin such as polytetrafluoroethylene.

2 , the reflective portion 5 is in the form of a sheet and is provided, for example, on the inner surface 2a of the container 2. The inner surface 2a of the container 2 is the inner surface of the container 2 that intersects the end portion where the window 3 is provided.

The sheet-shaped reflector 5 can be attached to the inner surface 2a of the container 2, for example, by using double-sided tape or other fasteners, or by screws or other fasteners. In these cases, the inner surface 2a of the container 2 may be curved. The sheet-shaped reflector 5 is flexible and can conform to the shape of the inner surface 2a of the container 2.

If the reflector 5 is too thick, it will be difficult for the reflector 5 to conform to the shape of the inner surface 2a of the container 2. If the reflector 5 is too thin, sufficient reflection of ultraviolet light will not be achieved, or the rigidity of the reflector 5 will be reduced, making installation of the reflector 5 difficult. Therefore, the thickness of the reflector 5 is preferably set to 300 μm or more and 1000 μm or less.

Figures 3(a) and 3(b) are schematic cross-sectional views illustrating the arrangement of a sheet-shaped reflective portion 5 on the inner surface 2a of a container 2. If the width of the sheet-shaped reflective portion 5 is too long, wrinkles and the like are likely to form when the reflective portion 5 is attached to the inner surface 2a of the container 2, thereby reducing workability. The width of the reflective portion 5 refers to its length in the direction of the central axis 2b of the container 2.

For example, if the length of the container 2 in the direction of the central axis 2b is short, a single reflector 5 may be attached to the inner side surface 2a of the container 2, as shown in Figure 3(a). If the length of the container 2 in the direction of the central axis 2b is long, multiple reflectors 5 may be arranged along the central axis 2b of the container 2 and attached to the inner side surface 2a of the container 2. For example, two reflectors 5 may be arranged and attached, as shown in Figure 3(b).

In this case, the width of the reflector 5 is preferably set to 1 μm or less. If the width of the reflector 5 is set to 1 μm or less, wrinkles are less likely to occur when the reflector 5 is attached to the inner surface 2a of the container 2, thereby improving workability.

Furthermore, when multiple reflectors 5 are arranged in a row, the periphery of a reflector 5 may abut or overlap the periphery of an adjacent reflector 5. If the periphery of a reflector 5 overlaps the periphery of an adjacent reflector 5, the overlapping portion may be welded. Welding the overlapping portion prevents the reflector 5 from peeling off. Furthermore, if the periphery of a reflector 5 overlaps the periphery of an adjacent reflector 5, the inner side surface 2a of the container 2 is not exposed, thereby preventing corrosion of the inner side surface 2a of the container 2.

Alternatively, a sheet-like reflective portion 5 may be further provided on the inner surface of the container 2 facing the window 3. For example, the reflective portion 5 may be bonded to the inner surface facing the window 3 or joined using double-sided tape. When the reflective portion 5 is provided on the inner surface facing the window 3, the thickness of the reflective portion 5 may be set to be greater than 300 μm and less than 1000 μm.

If the sheet-shaped reflector 5 containing fluororesin is placed on the inner surface 2a of the container 2, the ultraviolet light that enters the interior of the container 2 and is directed toward the inner surface 2a of the container 2 is easily reflected toward the fluid 301a within the interior of the container 2. This improves the efficiency of ultraviolet light utilization, thereby further enhancing the sterilization effect and increasing the treatment flow rate. Furthermore, if the sheet-shaped reflector 5 containing fluororesin is further placed on the inner surface facing the window 3, the efficiency of ultraviolet light utilization can be further improved.

The above examples illustrate the sheet-like reflective portion 5 , but a film-like reflective portion 5 a (corresponding to an example of the second reflective portion) may also be provided. That is, at least one sheet-like reflective portion 5 or film-like reflective portion 5 a may be provided on the inner surface of the container 2 .

Figure 4 is a schematic cross-sectional view illustrating a film-like reflective portion 5a. As shown in Figure 4, the film-like reflective portion 5a can be provided to cover the inner surface 2a of the container 2. The reflective portion 5a can be formed of a film containing a resin having high ultraviolet reflectivity and high resistance to ultraviolet light. For example, the reflective portion 5a can be formed of a film containing a silicone resin.

If the reflective portion 5a is too thick, it will easily peel off from the inner surface 2a of the container 2. If the reflective portion 5a is too thin, sufficient reflection of ultraviolet light will not be achieved. Therefore, the thickness of the reflective portion 5a is preferably set to 30 μm or more and 70 μm or less. Alternatively, a film-like reflective portion 5a may be further provided on the inner surface of the container 2 facing the window 3. The thickness of the reflective portion 5a provided on the inner surface facing the window 3 is also preferably set to 30 μm or more and 70 μm or less.

The film-like reflective portion 5a can be formed, for example, by applying a melted resin to the inner surface 2a of the container 2 and then heating it. For example, the resin applied to the inner surface 2a of the container 2 can be heated at 150°C for approximately one hour to harden, thereby forming the film-like reflective portion 5a. Alternatively, for example, the film-like reflective portion 5a can be formed by applying a melted resin to the inner surface 2a of the container 2 and the inner surface facing the window 3 and then heating and hardening them.

Providing a film-shaped reflective portion 5a achieves the same benefits as providing a sheet-shaped reflective portion 5. That is, ultraviolet light that irradiates the interior of container 2 and is directed toward inner surface 2a of container 2 is easily reflected toward fluid 301a within the interior of container 2. This improves the efficiency of ultraviolet light utilization, further enhancing sterilization effectiveness and increasing the treatment flow rate. Furthermore, providing the reflective portion 5a on the inner surface facing window 3 further enhances ultraviolet light utilization efficiency. Furthermore, since the film-shaped reflective portion 5a is easier to form than the sheet-shaped reflective portion 5, productivity can be improved and manufacturing costs can be further reduced.

Figure 5 is a schematic perspective view of a fluid sterilization device 1a illustrating another embodiment. Figure 6 is a schematic cross-sectional view of the fluid sterilization device 1a taken along line B-B in Figure 5 . As shown in Figure 5 , the fluid sterilization device 1a includes, for example, a container 2, a lid 13, a light source 14, and a reflector 5.

Lid 13 is plate-shaped and is attached to one end of container 2 in a liquid-tight manner. Lid 13 can be removably attached to the end of container 2 via, for example, a sealing member. Lid 13 blocks the opening at the end of container 2. The surface of lid 13 facing container 2 is exposed to the interior of container 2. A hole for inserting light source 14 is provided in the center of lid 13. Lid 13 is formed of a material resistant to ultraviolet rays and fluid 301a. For example, the material of lid 13 can be the same as that of container 2.

Light source 14 irradiates ultraviolet light into the interior of container 2. Light source 14 is, for example, detachably mounted on lid 13. Light source 14 comprises, for example, a discharge lamp 14a and a protective tube 14b. Discharge lamp 14a is mounted within protective tube 14b. Discharge lamp 14a extends within protective tube 14b. Discharge lamp 14a can, for example, be coaxial with protective tube 14b. The type of discharge lamp 14a is not particularly limited as long as it can irradiate ultraviolet light. Discharge lamp 14a can be, for example, a barrier discharge lamp or a mercury lamp.

Protective tube 14b is tubular, with one end closed and the other open. It extends between lid 13 and the end of container 2 on the side opposite lid 13. For example, protective tube 14b can be coaxially positioned with container 2. The space between inner surface 2a of container 2 and protective tube 14b forms a flow path for the fluid 301a being processed.

Ultraviolet light emitted from the discharge lamp 14a passes through the protective tube 14b and reaches the fluid 301a flowing within the container 2. Therefore, the protective tube 14b is formed from a material with high ultraviolet light transmittance. For example, the protective tube 14b can be formed from quartz glass. In addition, a portion of the ultraviolet light that reaches the interior of the container 2 is reflected by the reflector 5 and reaches the fluid 301a flowing within the container 2. By irradiating the fluid 301a flowing within the container 2 with ultraviolet light, the fluid 301a is sterilized.

In the above, the case where the sheet-shaped reflecting portion 5 is provided is exemplified, but the same can be applied as in the case where the film-shaped reflecting portion 5 a is provided.

The fluid sterilization device 1a of this embodiment can achieve the same effects as the fluid sterilization device 1. Specifically, the light source can be selected from any light source capable of irradiating ultraviolet light. For example, the light source can include a light-emitting element such as a light-emitting diode or a discharge lamp.

While some embodiments of the present invention have been described above, these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their variations are intended to be included within the scope and gist of the invention and are also intended to be included within the scope of the invention described in the patent application and its equivalents. Furthermore, the various embodiments described above may be implemented in combination with one another.

1.1a: Fluid sterilizer 2: Container 2a: Inner surface 2b: Center axis 3: Window 4.14: Light source 5.5a: Reflector 13: Lid 14a: Discharge lamp 14b: Protective tube 21: Supply tube 22: Discharge tube 41: Light-emitting element 42: Substrate 43: Retainer 301a, 301b: Fluid

Figure 1 is a schematic perspective view illustrating a fluid sterilization device according to the present embodiment. Figure 2 is a schematic cross-sectional view of the fluid sterilization device taken along line A-A in Figure 1. Figures 3(a) and 3(b) are schematic cross-sectional views illustrating a case where a sheet-shaped reflective portion is provided on the inner surface of a container. Figure 4 is a schematic cross-sectional view illustrating a film-shaped reflective portion. Figure 5 is a schematic perspective view illustrating a fluid sterilization device according to another embodiment. Figure 6 is a schematic cross-sectional view of the fluid sterilization device taken along line B-B in Figure 5.

1: Fluid sterilization device

2: Container

3: Window

4: Light Source

5: Reflector

21: Supply pipe

22: Discharge pipe

41: Light-emitting element

42:Substrate

43: Retainer

301a, 301b: Fluid

Claims (3)

A fluid sterilization device comprises: a container having a space within which a fluid to be processed can flow, the container comprising metal and extending in one direction; a light source capable of irradiating ultraviolet light into the space within the container; and a plurality of first or second reflective portions disposed on the inner surface of the container. The plurality of first reflective portions are sheet-shaped and comprise a fluororesin, and are arranged along the central axis of the container and attached to or bonded to the inner surface of the container. The second reflective portion is film-shaped and comprised of a silicone resin. Each of the plurality of first reflective portions has a thickness of 300 μm or greater and 1000 μm or less. The fluid sterilization device according to claim 1, wherein the thickness of the second reflecting portion is greater than or equal to 30 μm and less than or equal to 70 μm. A fluid sterilization device as described in claim 1, wherein the periphery of the first reflecting portion is connected to or overlaps with the periphery of the first reflecting portion adjacent to the first reflecting portion.