JP7632120B2 - Fluid Sterilization Device - Google Patents

Description

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

There is a fluid sterilization device that sterilizes a fluid such as water by irradiating it with ultraviolet light. For example, a fluid sterilization device has been proposed that includes a tubular section through which the fluid flows and a light source that is provided at the end of the tubular section and irradiates the inside of the tubular section with ultraviolet light. In this case, some of the ultraviolet light irradiated from the light source is directly irradiated onto the fluid flowing inside the tubular section. In addition, the ultraviolet light irradiated from the light source and incident on the inner surface of the tubular section propagates while repeatedly reflecting inside the tubular section.

This type of fluid sterilization device can also be used to sterilize seawater, groundwater, and the like. However, seawater and groundwater contain foreign matter such as sand, microbial corpses, and inorganic salts. Therefore, when the fluid sterilization device is used for such purposes, foreign matter may adhere to the liquid-contacting parts of the fluid sterilization device, reducing the sterilization effect.

For example, if foreign matter adheres to the inner surface of the tube, the reflectance decreases. When the reflectance decreases, the intensity of the reflected light (ultraviolet light) irradiated to the fluid decreases, reducing the sterilization effect. In addition, if foreign matter adheres to the window provided between the light source and the flow path, some of the ultraviolet light irradiated from the light source toward the fluid is blocked, reducing the sterilization effect.

In this case, disassembling the fluid sterilizing device to remove the attached foreign matter takes time and effort, and also reduces the operational rate of the fluid sterilizing device.
Therefore, there has been a demand for the development of a fluid sterilizing device that can suppress the adhesion of foreign matter.

JP 2018-69166 A JP 2017-051290 A

The problem that this invention aims to solve is to provide a fluid sterilization device that can suppress the adhesion of foreign matter.

The fluid sterilization device according to the embodiment comprises: a cylindrical tube made of stainless steel containing 8 wt% or more of Ni (nickel) ; a supply head provided at one end of the cylindrical tube; a discharge head provided at the other end of the cylindrical tube and having a hole penetrating between the end face on the cylindrical tube side and the end face opposite the cylindrical tube side; a substrate provided inside the hole of the discharge head; a light-emitting element provided on the surface of the substrate on the cylindrical tube side and capable of irradiating ultraviolet light; and a window provided in the discharge head and facing the light-emitting element. The inner surface of the cylindrical tube is in contact with seawater or groundwater containing foreign matter, and the surface roughness Ra of the inner surface of the cylindrical tube is 50 nm (nanometers) or less.

According to an embodiment of the present invention, a fluid sterilization device that can suppress adhesion of foreign matter can be provided.

FIG. 2 is a schematic cross-sectional view illustrating the fluid sterilization device according to the present embodiment.

Below, an embodiment will be illustrated with reference to the drawings. Note that in each drawing, similar components are given the same reference numerals and detailed explanations are omitted as appropriate.

FIG. 1 is a schematic cross-sectional view illustrating a fluid sterilizing device 1 according to this embodiment.
As shown in FIG. 1 , the fluid sterilization device 1 includes, for example, a tube portion 2 , a cover 3 , a supply head 4 , a discharge head 5 , a light source 6 , a window 7 , a cooling portion 8 , and a scraper 9 .

The tube portion 2 has a cylindrical shape and is open at both ends. The tube portion 2 can be, for example, a cylindrical tube. Ultraviolet light is irradiated from the light source 6 into the inside of the tube portion 2. If some of the irradiated ultraviolet light passes through the tube portion 2 and leaks to the outside, the processing capacity of the fluid sterilization device 1 will decrease. For this reason, the tube portion 2 is preferably formed from a material that is not permeable to ultraviolet light and has a high reflectance to ultraviolet light. For example, the tube portion 2 can be formed from a metal that has a high reflectance to ultraviolet light.

If the tube portion 2 contains a metal that has a high reflectivity for ultraviolet rays, it becomes easier to reflect the ultraviolet rays incident on the inner surface of the tube portion 2 toward the fluid 301a. This makes it possible to improve the efficiency of using the ultraviolet rays emitted from the light source 6. If the efficiency of using the ultraviolet rays can be improved, it becomes possible to reduce the number of light-emitting elements 61. Reducing the number of light-emitting elements 61 allows the light source 6 to be made smaller, less expensive, and more energy-efficient.

The internal space of the tube 2 serves as a flow path for the fluid 301a to be sterilized. Therefore, the fluid 301a comes into contact with the inner surface of the tube 2. Here, the fluid 301a may be seawater or groundwater. For example, when seawater comes into contact with the inner surface of the metal-containing tube 2, corrosion may occur. Therefore, it is preferable that the tube 2 is formed from a metal that has corrosion resistance against liquids that are prone to corrosion, such as seawater. For example, if the tube 2 is formed from stainless steel containing 8 wt% or more of Ni (nickel), it is possible to improve the reflectance against ultraviolet rays and the corrosion resistance against liquids that are prone to corrosion, such as seawater. As the stainless steel, for example, SUS304, SUS316, etc. can be used.

Furthermore, seawater, groundwater, and the like contain foreign matter such as sand, dead microorganisms, and inorganic salts. Since the fluid 301a comes into contact with the inner surface of the tube portion 2, if the fluid 301a contains foreign matter, the foreign matter will easily adhere to the inner surface of the tube portion 2. If foreign matter adheres to the inner surface of the tube portion 2, the reflectance of ultraviolet light may decrease. If the reflectance decreases, the intensity of the reflected light (ultraviolet light) irradiated to the fluid 301a decreases, and this may reduce the sterilization effect.
In this case, disassembling the fluid sterilization device 1 to remove the foreign matter adhering to the inner surface of the tubular portion 2 takes time and effort, and also reduces the operational rate of the fluid sterilization device 1.

According to the findings of the inventors, if the surface roughness (arithmetic mean roughness) Ra of the inner surface of the tube portion 2 is in the range of 50 nm (nanometers) or less, preferably in the range of 3 nm (nanometers) or more and 50 nm (nanometers) or less, it is possible to prevent foreign matter from adhering to the inner surface of the tube portion 2 and to improve the reflectance against ultraviolet rays. For example, by buffing the inner surface of the tube portion 2, it is possible to make the surface roughness Ra of the inner surface of the tube portion 2 fall within the above numerical range.

The cover 3 is cylindrical and has open ends on both sides. The cover 3 may be, for example, a cylindrical tube. The tube portion 2 is housed in the internal space of the cover 3. The material of the cover 3 is not particularly limited as long as it has a certain degree of rigidity. The material of the cover 3 may be, for example, a metal such as stainless steel. The cover 3 may be fixed to the supply head 4 and the discharge head 5. There is no particular limit to the method of fixing the cover 3. For example, one end of the cover 3 may be provided inside a recess or groove provided in the supply head 4, and the other end of the cover 3 may be provided inside a recess or groove provided in the discharge head 5. In addition, for example, flanges may be provided at both ends of the cover 3, one flange may be fixed to the supply head 4 with a screw or the like, and the other flange may be fixed to the discharge head 5 with a screw or the like.
The cover 3 is not necessarily required and may be omitted. However, if the cover 3 is provided, it is possible to prevent an external force from acting directly on the cylindrical portion 2.

The supply head 4 is provided at one end of the tubular portion 2. A seal member (not shown) can be provided between the supply head 4 and the end of the tubular portion 2. The seal member provides a liquid-tight seal between the supply head 4 and the tubular portion 2. The seal member can be, for example, an O-ring.

The supply head 4 is, for example, cylindrical, and has a hole 4a that penetrates between the end face on the cylindrical portion 2 side and the end face on the opposite side to the cylindrical portion 2 side. The opening of the hole 4a on the cylindrical portion 2 side is connected to the internal space of the cylindrical portion 2. The opening of the hole 4a on the opposite side to the cylindrical portion 2 side is the supply port 4a1. A supply source of the fluid 301a can be connected to the supply port 4a1 via piping. A filter, a straightening plate, etc. can also be provided inside the hole 4a.

The material of the supply head 4 is not particularly limited as long as it is resistant to the fluid 301a and ultraviolet rays. The material of the supply head 4 can be, for example, a metal such as stainless steel. As mentioned above, when the fluid 301a is a liquid that is prone to corrosion, such as seawater, it is preferable to form the supply head 4 from stainless steel containing 8 wt% or more of Ni. In this way, corrosion of the supply head 4 can be suppressed even when sterilizing seawater or the like.

The discharge head 5 is provided at the other end of the tubular portion 2. A seal member (not shown) can be provided between the discharge head 5 and the end of the tubular portion 2. The seal member provides a liquid-tight seal between the discharge head 5 and the tubular portion 2. The seal member can be, for example, an O-ring.

The discharge head 5 has, for example, a cylindrical shape and has a hole 5a and a hole 5b.
The opening of the hole 5a on the cylindrical portion 2 side is connected to the internal space of the cylindrical portion 2. The opening of the hole 5a on the opposite side to the cylindrical portion 2 side is an outlet 5a1 provided on the side of the discharge head 5. The sterilized fluid 301b is discharged from the outlet 5a1. A tank or the like that stores the sterilized fluid 301b can be connected to the outlet 5a1 via piping.
The hole 5a has a flow path 5a2 that is approximately parallel to the end face of the discharge head 5 on the side of the cylindrical portion 2, and a flow path 5a3 that extends in the axial direction of the discharge head 5.

The flow passage 5a2 opens to an end surface of the discharge head 5 on the side of the cylindrical portion 2. A window 7 is exposed on the inner wall of the flow passage 5a2. The flow passage 5a2 is, for example, a disk-shaped space.
One end of the flow path 5a3 is connected to the vicinity of the periphery of the flow path 5a2. The other end of the flow path 5a3 is connected to the outlet 5a1. The flow path 5a3 is, for example, a cylindrical space.

The ultraviolet light emitted from the light source 6 enters the flow path 5a2 through the window 7. Therefore, the fluid 301a flowing through the flow path 5a2 is sterilized by the ultraviolet light. In addition, a portion of the ultraviolet light that enters the flow path 5a2 is irradiated into the internal space of the tube portion 2. A portion of the ultraviolet light that is irradiated into the internal space of the tube portion 2 is reflected by the inner surface of the tube portion 2. Therefore, the fluid 301a flowing inside the tube portion 2 is sterilized by the ultraviolet light.

The hole 5b opens to the flow path 5a2 and to the end face of the discharge head 5 opposite the cylindrical portion 2 side. That is, the discharge head 5 has holes (hole 5b and hole 5a) penetrating between the end face on the cylindrical portion 2 side and the end face opposite the cylindrical portion 2 side.
In the hole 5b, for example, a protrusion 63b of a holder 63, a substrate 62, and a light emitting element 61 are provided.

The material of the discharge head 5 is not particularly limited as long as it is resistant to the fluids 301a, 301b and ultraviolet rays. The material of the discharge head 5 can be, for example, a metal such as stainless steel. As mentioned above, when the fluids 301a, 301b are liquids that are prone to corrosion, such as seawater, it is preferable to form the discharge head 5 from stainless steel containing 8 wt% or more of Ni. In this way, corrosion of the discharge head 5 can be suppressed even when sterilizing seawater or the like.

The light source 6 is detachably provided on the discharge head 5 .
The light source 6 includes, for example, a light emitting element 61 , a substrate 62 , and a holder 63 .
The light-emitting element 61 is provided on the surface of the substrate 62 facing the tube portion 2. The light-emitting element 61 irradiates ultraviolet light toward the window 7. At least one light-emitting element 61 can be provided. When a plurality of light-emitting elements 61 are provided, the plurality of light-emitting elements 61 can be connected in series. There are no particular limitations on the light-emitting element 61 as long as it is an element that generates ultraviolet light. The light-emitting element 61 can be, for example, a light-emitting diode or a laser diode.

There are no particular limitations on the peak wavelength of the ultraviolet light emitted from the light-emitting element 61, so long as it has a sterilizing effect. However, if the peak wavelength is between 255 nm and 290 nm, the sterilizing effect can be improved. Therefore, it is preferable to use a light-emitting element 61 that can radiate ultraviolet light with a peak wavelength between 255 nm and 290 nm.

The substrate 62 is plate-shaped and is provided on the end surface of the protruding portion 63b on the cylindrical portion 2 side. A wiring pattern can be provided on the substrate 62. The material of the substrate 62 is preferably one that is resistant to ultraviolet light. The material of the substrate 62 can be, for example, ceramics such as aluminum oxide. The substrate 62 can also be a metal plate with the surface covered with an inorganic material (metal core substrate). If the material of the substrate 62 is ceramics or the substrate 62 is a metal core substrate, it is possible to obtain resistance to ultraviolet light and high heat dissipation properties.

The holder 63 can be detachably attached to the discharge head 5. Although the light-emitting element 61 has a longer life than a discharge lamp or the like, the light-emitting efficiency decreases as the lighting time increases. It is also possible that the light-emitting element 61 will break down and stop lighting. If the holder 63 is detachably attached to the discharge head 5, it will be easy to replace the light-emitting element 61.

The holder 63 has, for example, a flange 63a and a protrusion 63b. The flange 63a and the protrusion 63b can be integrally formed.
The flange 63a has a plate shape and is provided on the end surface of the discharge head 5 opposite to the cylindrical portion 2. The flange 63a is attached to the discharge head 5 using a fastening member such as a screw.

The protrusion 63b is provided on the surface of the flange 63a facing the tube portion 2. The protrusion 63b protrudes from one surface of the flange 63a and is provided inside the hole 5b of the discharge head 5. A substrate 62 on which the light-emitting element 61 is mounted can be provided on the end surface of the protrusion 63b facing the tube portion 2. The protrusion 63b can also have the function of determining the position of the light-emitting element 61 relative to the discharge head 5. For example, the side surface of the protrusion 63b can be brought into contact with the inner wall of the hole 5b of the discharge head 5. In this way, the position of the light-emitting element 61 relative to the discharge head 5 can be determined.

In addition, the hole 5b of the discharge head 5 and the flow path 5a2 are separated by a window 7, so the discharge head 5 (light source 6) can be attached and detached even when fluid 301a is present in the flow path 5a2. This improves maintainability.

The holder 63 also has the function of dissipating heat generated in the light-emitting element 61 to the outside. For this reason, it is preferable that the holder 63 is made of a material with high thermal conductivity. The holder 63 can be made of a metal such as aluminum, copper, or stainless steel. In addition, heat dissipation fins can be provided on the end face of the holder 63 opposite the tube portion 2 side, or on the side.

The window 7 has a plate shape and is provided, for example, on the inner wall of the hole 5b of the discharge head 5 so as to be liquid-tight. That is, the window 7 is provided on the discharge head 5, and one surface is exposed to the flow path 5a2 provided on the discharge head 5. The planar shape of the window 7 can be, for example, a rectangle. If the planar shape of the window 7 is a rectangle, it becomes easy to bring the scraper 9 into contact with the entire surface of the window 7. Therefore, it becomes easy to remove foreign matter adhering to the window 7.

The window 7 faces the light-emitting element 61. A space 5b1 can be provided between the window 7 and the light-emitting element 61. The window 7 is made of a material that is transparent to ultraviolet light and has resistance to ultraviolet light and the fluid 301a. The window 7 is made of, for example, quartz or a fluororesin that transmits ultraviolet light.

An anti-reflection film can also be provided on the surface of the window 7 facing the light-emitting element 61. If an anti-reflection film is provided, it is possible to prevent the ultraviolet light irradiated from the light-emitting element 61 from being reflected by the window 7 and becoming difficult to irradiate onto the fluid 301a. In other words, it is possible to improve the efficiency of use of the ultraviolet light irradiated from the light-emitting element 61.

An anti-soiling film can also be provided on the surface of the window 7 facing the tube portion 2. As mentioned above, the fluid 301a may contain foreign matter. If foreign matter adheres to the window 7, it becomes difficult for the ultraviolet light emitted from the light-emitting element 61 to pass through the window 7. If an anti-soiling film is provided, it is possible to prevent foreign matter from adhering to the window 7.

The cooling unit 8 can be provided, for example, on the side of the holder 63 opposite the light emitting element 61 side. The cooling unit 8 is, for example, a fan that supplies air to the holder 63. If the holder 63 is provided with heat dissipation fins, the cooling unit 8 can be a fan that supplies air to the heat dissipation fins. The cooling unit 8 can also be, for example, a unit that supplies liquid to a flow path provided in the holder 63. That is, the cooling unit 8 can be an air-cooled type or a liquid-cooled type.

The cooling unit 8 may be omitted depending on the number of light-emitting elements 61, the amount of heat generated, the temperature and flow rate of the fluid 301a, etc. However, if the cooling unit 8 is provided, the temperature of the light-emitting elements 61 is less likely to exceed the maximum junction temperature even if the number of light-emitting elements 61 or the applied power is increased.

In addition, if the cooling unit 8 is provided, the temperature of the light-emitting element 61 is less likely to exceed the maximum junction temperature even if the temperature of the fluid 301a increases or the flow rate of the high-temperature fluid 301a increases. Therefore, the range of compatible fluids 301a can be expanded.

Here, the fluid 301a comes into contact with the surface of the window 7 facing the tube portion 2, so if the fluid 301a contains foreign matter, the foreign matter will easily adhere to the surface of the window 7 facing the tube portion 2. If foreign matter adheres to the window 7, it becomes difficult for the ultraviolet light irradiated from the light source 6 to enter the flow path 5a2. This may reduce the sterilization effect.

As mentioned above, if an anti-fouling film is provided on the surface of the window 7 facing the tube portion 2, it is possible to prevent foreign matter from adhering. However, even if an anti-fouling film is provided, it may be difficult to prevent the adhesion of foreign matter when the fluid 301a contains a large amount of foreign matter.

In this case, disassembling the fluid sterilization device 1 to remove the foreign matter adhering to the window 7 takes time and effort, and the operational rate of the fluid sterilization device 1 also decreases.
Therefore, the fluid sterilization device 1 is provided with a scraper 9 for removing foreign matter adhering to the window 7 .

The scraper 9 can be provided on the discharge head 5. A seal member 10 can be provided between the scraper 9 and the discharge head 5. The seal member 10 provides a liquid-tight seal between the scraper 9 and the discharge head 5.

The scraper 9 may be movable along the surface of the window 7 while in contact with the surface of the window 7 facing the cylindrical portion 2. For example, one end 9a of the scraper 9 may be in contact with the surface of the window 7 facing the cylindrical portion 2. For example, the other end 9b of the scraper 9 may be exposed from the discharge head 5. For example, the scraper 9 may be movable in a direction perpendicular to the central axis of the cylindrical portion 2.
If such a scraper 9 is provided, foreign matter adhering to the window 7 can be scraped off.

The scraper 9 may be moved, for example, by an operator, or by a driving device such as a motor or an air cylinder. The scraper 9 may remove foreign matter according to the amount of foreign matter attached, or may be removed periodically.

The material of the scraper 9 is not particularly limited as long as it is resistant to the fluid 301a and ultraviolet rays. The material of the scraper 9 can be, for example, a metal such as stainless steel. As mentioned above, when the fluid 301a is a liquid that is prone to corrosion, such as seawater, it is preferable to form the scraper 9 from stainless steel containing 8 wt% or more of Ni. In this way, corrosion of the scraper 9 can be suppressed even when sterilizing seawater or the like.

Although several embodiments of the present invention have been illustrated above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their variations are included within the scope and gist of the invention, as well as within the scope of the invention and its equivalents described in the claims. Furthermore, the above-mentioned embodiments can be implemented in combination with each other.

1 Fluid sterilization device, 2 Cylinder, 4 Supply head, 5 Discharge head, 6 Light source, 7 Window, 9 Scraper, 61 Light emitting element, 63 Holder, 63b Convex portion, 301a Fluid, 301b Fluid

Claims (2)

A cylindrical portion formed of stainless steel containing 8 wt % or more of Ni (nickel) and having a cylindrical shape ;
a supply head provided at one end of the cylindrical portion;
a discharge head provided at the other end of the cylindrical portion and having a hole penetrating between an end face on the cylindrical portion side and an end face opposite to the cylindrical portion side;
a substrate disposed within the bore of the ejection head;
a light-emitting element provided on a surface of the substrate facing the cylindrical portion and capable of emitting ultraviolet light;
a window provided in the discharge head and facing the light emitting element;
Equipped with
The inner surface of the cylindrical portion is in contact with seawater or groundwater containing foreign matter,
A fluid sterilization device, wherein the surface roughness Ra of the inner surface of the cylindrical portion is 50 nm (nanometers) or less. The scraper further includes a scraper that can reciprocate along the surface of the window with one end in contact with the surface of the window on the cylindrical portion side ,
2. The fluid sterilizing device according to claim 1 , wherein the one end of the scraper is positioned on the peripheral edge side of the window when foreign matter adhering to the window is not removed .

Images