JP2022163644A - Fluid sterilization device - Google Patents

Abstract

To provide a fluid sterilization device using ultraviolet LED in which the sterilization efficiency is improved.SOLUTION: The fluid sterilization device has a housing 10, an ultraviolet LED 11 and a partition wall 12. The partition wall 12 is provided in the inside of the housing 10. The partition wall 12 has a retention space 20 in which water is retained. The side surface 20b of the retention space 20 is an outwardly convex curved surface, and the cross-sectional shape of the plane including the water inflow direction (coaxial with the axial direction of the pipe 15) into the retention space 20 is a golden spiral. Further, the golden spiral is a spiral whose radius of curvature gradually decreases toward the side opposite to the water inflow direction into the retention space 20.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apparatus for sterilizing liquids by irradiating them with ultraviolet rays. In particular, it relates to the one using an ultraviolet LED as a light source.

A sterilization device that sterilizes bacteria and viruses in running water by irradiating ultraviolet rays is known. Mercury lamps are widely used as light sources. Mercury lamps, which use mercury, are highly toxic and have a large environmental load. Another problem is that the size of the sterilization apparatus becomes large when a mercury lamp is used. Therefore, replacement of mercury lamps with ultraviolet LEDs is underway. There are Patent Documents 1 to 3 as fluid sterilization devices using ultraviolet LEDs.

Patent Literature 1 describes a fluid sterilizer in which an inlet and an outlet are provided on the upper and lower surfaces of a cylindrical housing, respectively, and an ultraviolet LED is provided on the lower surface side facing the inlet.

Patent Literature 2 describes a fluid sterilizer in which a housing is an integrating ellipsoid or an integrating sphere, and ultraviolet LEDs are arranged on the side surface. Further, it is described that a mechanical baffle is provided inside the housing at a position facing the inlet to increase the retention time of the fluid, thereby improving the sterilization efficiency.

Patent Literature 3 describes that the container is double-layered with an outer and an inner side, and fluid that has flowed into the outer container flows into the inner container through a gap between the outer container and the inner container. It also describes that the shape of the container is a cylinder or a sphere.

Japanese Patent Publication No. 2020-530384 Japanese Patent No. 5432286 Japanese Patent Publication No. 2020-521556

However, if an ultraviolet LED is used as the light source, the size of the device can be reduced, but there is a problem that the ultraviolet irradiation time is shortened and the sterilization efficiency is lowered.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to improve the sterilization efficiency of a fluid sterilizer that uses an ultraviolet LED as a light source.

The present invention provides a housing having an inflow port and an outflow port, and discharging a fluid introduced through the inflow port from the outflow port, and a partition disposed inside the housing and having a retention space for retaining the fluid. and an ultraviolet light emitting element for irradiating the fluid in the retention space with ultraviolet light, the retention space having a side surface that forms an angle with the direction of flow of the fluid into the retention space, and the direction of flow of the side surface The fluid sterilizer is characterized in that the cross-sectional shape of the plane containing the fluid is a helical shape in which the radius of curvature gradually decreases toward the side opposite to the inflow direction.

The outflow direction of the fluid from the retention space may be opposite to the inflow direction of the fluid into the retention space.

The partition wall may be made of a reflective material that reflects ultraviolet light emitted from the ultraviolet light emitting element.

A channel for the fluid discharged from the retention space may be provided between the inner wall of the housing and the partition wall, and the ultraviolet light emitting element may be arranged in the channel.

The ultraviolet light emitting elements may be arranged facing the inflow direction.

The housing may be spherical.

According to the present invention, the average residence time of fluid in the residence space inside the housing can be lengthened. As a result, the irradiation time of ultraviolet rays to the fluid can be lengthened, and the sterilization efficiency can be improved.

The figure which showed the cross section of the fluid sterilization apparatus of Example 1. FIG. 4 is a diagram showing the flow of water inside the housing 10; FIG.

Specific examples of the present invention will be described below with reference to the drawings, but the present invention is not limited to the examples.

FIG. 1 is a cross-sectional view of the fluid sterilizer of Example 1. FIG. As shown in FIG. 1, the fluid sterilizer of Example 1 has a housing 10, an ultraviolet LED (ultraviolet light emitting device) 11, and a partition wall 12. As shown in FIG.

The housing 10 is spherical and has a space for introducing water therein. The housing 10 has an inlet 13 for supplying water to the inside of the housing 10 and an outlet 14 for discharging water to the outside of the housing 10 . The inflow port 13 and the outflow port 14 are coaxially opposed to each other with respect to the spherical axis of the housing 10 . The housing 10 is made of SUS (stainless steel), for example.

Inside the housing 10 , a pipe 15 is provided continuously with the inlet 13 . The tube 15 is cylindrical and arranged coaxially with the axis of the sphere of the housing 10 . Further, the pipe 15 extends to the vicinity of the central portion of the housing 10 (retention space 20 to be described later). This pipe 15 guides the water from the inlet 13 to the retention space 20 .

The ultraviolet LED 11 is an LED that emits ultraviolet light having a wavelength suitable for sterilizing fluid. For example, the wavelength is 250-280 nm. The ultraviolet LED 11 is mounted on a substrate 16 , and the substrate 16 is arranged inside the third channel 23 . Further, the substrate 16 is arranged so that the ultraviolet rays emitted from the ultraviolet LEDs 11 pass through the glass plate 17 and irradiate the retention space 20 and the inside of the tube 15 .

The partition 12 is provided inside the housing 10 . The partition wall 12 is provided to form a predetermined flow path inside the housing 10 , and the flow path is set by the shape of the housing 10 . The flow path includes a retention space 20 in which water stays, a first flow path 21 in which water flows along the outer wall of the inflow, a second flow path 22 in which water flows along the inner wall of the housing, and an ultraviolet LED 11. and a third flow path 23 in which the substrate 16 is arranged and water flows on the back surface of the substrate 16 .

The retention space 20 is a space for retaining water from the pipe 15 . The retention space 20 faces the pipe 15 and has a bottom surface 20a that is a plane perpendicular to the axis of the pipe 15 and a side surface 20b that forms an angle with the plane and extends toward the pipe 15 side.

A bottom surface 20a of the retention space 20 has a circular hole 20c. The hole 20c is covered with a glass plate 17 arranged outside the partition wall 12 and inside the third channel 23, and the hole 20c is sealed. Ultraviolet rays from the ultraviolet LEDs 11 are transmitted through the glass plate 17 and radiated to the retention space 20 through the holes 20c. The glass plate 17 may be made of any material as long as it transmits ultraviolet rays emitted from the ultraviolet LEDs 11, such as quartz glass. In addition, the bottom surface 20a is not limited to a flat surface, and may be a curved surface.

A side surface 20b of the retention space 20 is an outwardly convex curved surface, and the cross-sectional shape of the surface including the inflow direction of water into the retention space 20 (coaxial with the axial direction of the pipe 15) is a golden spiral. . The golden spiral is a spiral whose radius of curvature gradually decreases toward the side opposite to the inflow direction of water into the retention space 20 . In a cross section along a plane including the inflow direction of water into the retention space 20, as shown in FIG. The golden spiral, the left side surface 20b is a counterclockwise (left-handed) golden spiral.

The first flow path 21 is a flow path formed between the outer surface of the pipe 15 and the partition wall 12 , and is a flow path into which water flows from the retention space 20 . Since the direction of the first channel 21 is parallel to the inflow direction of water into the retention space 20, the direction of discharge of water from the retention space 20 to the first channel 21 is opposite to the inflow direction. Therefore, it is difficult for water to be discharged from the retention space 20, and as a result, the average retention time of water in the retention space 20 is increased. In other words, the flow velocity distribution in the housing 10 is made uniform, and the whole is irradiated with ultraviolet light for the same time.

The second flow path 22 is a flow path formed between the side portion of the partition wall 12 and the inner wall of the housing 10 and connects the first flow path 21 and the third flow path 23 . The water that has flowed from the first flow path 21 into the second flow path 22 flows along the radial direction of the housing 10, then flows along the inner wall of the housing 10 toward the outflow port 14 side, and flows into the third flow path. Flow into 23.

The third channel 23 is a channel formed in a gap between the lower portion of the partition wall 12 and the inner wall of the housing 10 . A space for arranging the substrate 16 on which the ultraviolet LED 11 is mounted is secured by the third flow path 23 . The substrate 16 is sealed with a sealing portion 18 for waterproofing. The water that has flowed into the third flow path 23 from the second flow path 22 flows into the outflow port 14 while contacting the sealing portion 18 and is discharged to the outside of the housing 10 . A hole is provided in the sealing portion 18 and the housing 10 , and the hole is connected by a wiring tube 19 . Wiring (not shown) from the substrate 16 is led out through the wiring tube 19 .

The partition 12 is made of PTFE (polytetrafluoroethylene). By using PTFE, resistance to ultraviolet rays is ensured, and ultraviolet rays are reflected on the side surface 20b to improve the efficiency of irradiating the water with ultraviolet rays, thereby improving the sterilization efficiency. Any material other than PTFE may be used as long as it has resistance to ultraviolet rays. For example, SUS (stainless steel) or Al may be used. Further, when a material having a low ultraviolet reflectance is used as the material of the partition walls 12, a reflective film made of a material having a high ultraviolet reflectance may be provided on the side surface 20b.

Next, the operation of the fluid sterilizer according to the first embodiment will be described. The water that has flowed in from the inlet 13 is guided to the retention space 20 inside the housing 10 via the pipe 15 . Since the bottom surface 20 a of the retention space 20 faces the pipe 15 , the flow of water is blocked by the bottom surface 20 a and the water flows along the side surface 20 b of the retention space 20 . Here, the shape of the side surface 20b is an outwardly convex curved surface, and the cross-sectional shape of the plane including the inflow direction of the water into the retention space 20 is a golden spiral, so the water swirls within the retention space 20. flow like In addition, since the direction of water inflow from the pipe 15 and the direction of water discharge to the first flow path 21 are opposite to each other, water is less likely to be discharged from the retention space 20 . Therefore, water stays in the staying space 20 for a long time. As a result, the irradiation time of the ultraviolet rays to the water in the retention space 20 is lengthened, and the sterilization efficiency is improved.

In addition, the water sterilized in the retention space 20 flows to the third flow path 23 through the first flow path 21 and the second flow path 22, contacts the sealing portion 18, and is discharged from the outflow port 14. be. Therefore, it is possible to efficiently cool the ultraviolet LED 11 through the sealing portion 18 .

FIG. 2 shows the result of simulating the flow of water in the housing 10 for the fluid sterilizer of Example 1. As shown in FIG. As shown in FIG. 2, it can be seen that the water swirls within the retention space 20 along the spiral shape of the side surface 20b, and the average retention time of water within the retention space 20 is increased.

As described above, according to the fluid sterilizer of the first embodiment, the cross-sectional shape of the side surface 20b of the retention space 20 on the plane including the inflow direction of water into the retention space 20 is a golden spiral. It can increase the average residence time of water in the As a result, the irradiation time of ultraviolet rays to the fluid can be lengthened, and the sterilization efficiency can be improved.

In addition, in Example 1, the shape of the side surface of the retention space 20 is a golden spiral, but any spiral shape may be used, and the curvature may not only change continuously, but may also change stepwise. For example, it may be a logarithmic spiral, an Archimedean spiral, a hyperbolic spiral, or the like.

Moreover, in the first embodiment, the shape of the housing 10 is spherical, but the shape is not limited to this and may be any shape. For example, it may have a shape such as a hemisphere, a cylinder, or an elliptical sphere. However, in order to improve sterilization efficiency by irradiating water with ultraviolet rays from the ultraviolet LED 11 at a short distance, a spherical shape is preferable as in the first embodiment.

In addition, although an example in which the sterilization object is water is shown in the first embodiment, the present invention is not limited to sterilization of water, and can be used for sterilization of any fluid.

A plurality of fluid sterilizers of Example 1 may be connected in parallel or in series. By connecting in parallel, more fluids can be processed at the same time. Moreover, the sterilization efficiency can be further improved by connecting in series.

Since the sterilization device of the present invention can be miniaturized, it is suitable for water sterilization in domestic water heaters and the like.

10: Housing 11: Ultraviolet LED
12: partition wall 13: inlet 14: outlet 15: tube 16: substrate 17: glass plate 20: retention space 21: first channel 22: second channel 23: third channel

Claims (6)

a housing having an inflow port and an outflow port, and discharging a fluid introduced from the inflow port from the outflow port;
a partition disposed inside the housing and having a retention space for retaining the fluid;
an ultraviolet light emitting element for irradiating the fluid in the retention space with ultraviolet light;
has
the retention space has a side surface that forms an angle with the inflow direction of the fluid into the retention space;
The cross-sectional shape of the side surface including the inflow direction is a helical shape in which the radius of curvature gradually decreases toward the side opposite to the inflow direction.
A fluid sterilizer characterized by: 2. The fluid sterilizer according to claim 1, wherein the direction of the fluid flowing out of the retention space is opposite to the direction of the fluid flowing into the retention space. 3. The fluid sterilizer according to claim 1, wherein said partition wall is made of a reflective material that reflects ultraviolet rays from said ultraviolet light emitting element. 3. A flow path for fluid discharged from said retention space is provided between an inner wall of said housing and said partition wall, and said ultraviolet light emitting element is arranged in said flow path. 4. A fluid disinfection device according to claim 1 or claim 3. 5. The fluid sterilizer according to any one of claims 1 to 4, wherein the ultraviolet light emitting elements are arranged to face the inflow direction. 6. The fluid sterilizer according to any one of claims 1 to 5, wherein the housing is spherical.

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