Fluid sterilization device

Abstract

A fluid sterilization device (1) has: a cylindrical inner tube (20) having a cutout portion (21a) that penetrates in a radial direction and an outlet tube (22) that protrudes in a radial direction; an outer tube (10) that has an annular space (28) that communicates with the cutout portion (21a) between the inner tube (20) and the outer tube (10) and houses the inner tube (20); an inflow tube (12) that is provided to the outer tube (10) and through which fluid flows in; an outflow tube (13) that is coaxially provided with the inflow tube (12) and is connected to the outlet tube (22) to allow fluid that has passed through the annular space (28) to flow out; and a light source (55) that irradiates ultraviolet light to fluid that passes through the inside of the inner tube (20) via an ultraviolet light transmission window.

Description

Technical Field

[0001] This invention relates to a fluid sterilization device that uses ultraviolet light to sterilize fluids flowing in a flow path. Background Technology

[0002] In recent years, the bactericidal effect of ultraviolet light (wavelength 240–380 nm) has been utilized in food sterilization lamps, medical devices, and other applications. Additionally, there is a known device that uses ultraviolet LEDs to irradiate fluids flowing in a flow path with ultraviolet light, sterilizing the fluids for use as cleaning water, etc.

[0003] For example, the fluid sterilization device described in Patent Document 1 consists of a substrate on which a light source is mounted, a housing (the sterilization section of the fluid) having a straight tube-shaped flow path, a fluid inlet, a fluid outlet, and a reflector arranged to surround the cylinder. The cylinder is made of quartz, which is a material that transmits ultraviolet light, so ultraviolet light emitted from the light source can pass through the cylinder.

[0004] The fluid is exposed to ultraviolet light, which is emitted from a light source embedded in an opening of a reflector and diffused through the reflector. This promotes the sterilization of the fluid (Patent Document 1 / paragraphs 0038, 0039, 0050). Figure 2 ).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2020-92856 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The fluid sterilization device in Patent Document 1 uses a straight pipe flow path, thus achieving uniform flow velocity distribution by extending the run-up section. However, in this fluid sterilization device, sterilization efficiency cannot be improved without using a reactor that is longer than that of conventional fluid sterilization devices, resulting in the problem of device enlargement.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a small fluid sterilization device that can efficiently irradiate fluid with ultraviolet light.

[0011] Methods for solving problems

[0012] The fluid sterilization device of the present invention is characterized by comprising: a cylindrical inner tube, one end of which is open in the axial direction, and having a radially penetrating slit and a radially protruding outlet tube; an outer tube having an annular space communicating with the slit between itself and the inner tube, and housing the inner tube; an inflow tube disposed on the outer tube for fluid to flow in; an outflow tube coaxially disposed with the inflow tube of the outer tube and connected to the outlet tube for the fluid to flow out after passing through the annular space; and a light source that irradiates the fluid passing through the interior of the inner tube with ultraviolet light through an ultraviolet light transmission window at the end of the outer tube that seals one end.

[0013] The fluid sterilization device mainly consists of an inner tube and an outer tube. The inner tube is cylindrical, open at one axial end, has a radially penetrating slit, and has a radially protruding outlet tube. Additionally, a light source irradiates the fluid passing through the inner tube with ultraviolet light through a window, thus sterilizing the fluid.

[0014] The outer tube has an inlet pipe and an outlet pipe for fluid, and an annular space communicating with the cut-out portion between it and the inner tube. The inner tube is housed inside the outer tube. Furthermore, the outlet pipe is connected to the outlet pipe of the inner tube. Fluid flows in from the inlet pipe and passes through the annular space. Moreover, the fluid enters the interior of the inner tube through the cut-out portion and is sterilized, then flows out from the outlet pipe via the outlet pipe. Therefore, the fluid sterilization device of the present invention can be a smaller device than conventional fluid sterilization devices in the linear direction, thereby enabling efficient irradiation of the fluid with ultraviolet light.

[0015] In the fluid sterilization device of the present invention, preferably, the reflector plate that reflects the ultraviolet light is disposed on the side of the ultraviolet light transmission window opposite to the inner tube.

[0016] The ultraviolet light is reflected by the reflector, so it travels not only through the window into the inner tube but also into the annular space. This allows the device to improve the sterilization efficiency of the fluid.

[0017] Furthermore, in the fluid sterilization device of the present invention, it is preferable to have an illuminance sensor on the back side of the reflector, the reflector having an opening, and the illuminance sensor detecting the illuminance of the ultraviolet light through the opening.

[0018] The fluid sterilization device of the present invention has an illuminance sensor on the back side of the reflector. Furthermore, the reflector has an opening through which the illuminance sensor can detect the illuminance of ultraviolet light. Therefore, this device can determine whether ultraviolet light has irradiated the fluid.

[0019] Furthermore, in the fluid sterilization device of the present invention, it is preferable that the cut portions are arranged in pairs at symmetrical positions relative to the central axis of the inner tube.

[0020] The cutouts are arranged in pairs symmetrically with respect to the central axis of the inner tube. Therefore, this device can ensure that the fluid flowing into the annular space flows evenly into the interior of the inner tube, thus achieving uniform flow velocity distribution.

[0021] Furthermore, in the fluid sterilization device of the present invention, it is preferable that the inner tube is formed of a resin material.

[0022] When the inner tube is formed using a resin material (e.g., PTFE), the inner tube diffuses and reflects ultraviolet light. Therefore, this device can improve the efficiency of ultraviolet light irradiation, further enhancing the sterilization efficiency of the fluid. Attached Figure Description

[0023] Figure 1 This is a perspective view of the fluid sterilization device of this embodiment.

[0024] Figure 2 yes Figure 1 An exploded view of the fluid sterilization device.

[0025] Figure 3 Viewed from the side of the cover Figure 1 A plan view of the fluid sterilization device.

[0026] Figure 4 yes Figure 3 IV-IV sectional view of the fluid sterilization device.

[0027] Figure 5 Viewed from the front side Figure 1 A plan view of the fluid sterilization device.

[0028] Figure 6 yes Figure 5 VI-VI sectional view of the fluid sterilization device.

[0029] Figure 7 yes Figure 5 Sectional view VII-VII of the fluid sterilization device.

[0030] Figure 8A (a) indicates Figure 3 The flow velocity distribution in the IV-IV cross-sectional view of the fluid sterilization device.

[0031] Figure 8A (b) indicates Figure 5 The flow velocity distribution in the VI-VI cross-sectional view of the fluid sterilization device.

[0032] Figure 8A (c) indicates Figure 5 The flow velocity distribution in the VII-VII cross-sectional view of the fluid sterilization device.

[0033] Figure 8B (a) indicates Figure 6 The flow velocity distribution in the horizontal cross section H of the fluid sterilization device.

[0034] Figure 8B (b) indicates Figure 6 The velocity distribution of the oblique cross section X of the fluid sterilization device.

[0035] Figure 8B (c) indicates Figure 6 The velocity distribution in the oblique section Y of the fluid sterilization device.

[0036] Figure 9A (a) indicates Figure 3 Illumination distribution in the IV-IV cross-sectional view of the fluid sterilization device.

[0037] Figure 9A (b) indicates Figure 5 Illumination distribution in VI-VI cross-sectional view of the fluid sterilization device.

[0038] Figure 9A (c) indicates Figure 5 Illumination distribution in sectional view VII-VII of the fluid sterilization device.

[0039] Figure 9B (a) indicates Figure 6 Illumination distribution in the horizontal cross section H of the fluid sterilization device.

[0040] Figure 9B (b) indicates Figure 6 Illumination distribution of the oblique cross section X of the fluid sterilization device.

[0041] Figure 9B (c) indicates Figure 6 Illumination distribution of the oblique cross section Y of the fluid sterilization device. Detailed Implementation

[0042] Hereinafter, embodiments of the fluid sterilization apparatus of the present invention will be described with reference to the accompanying drawings.

[0043] Figure 1 This is a perspective view of the fluid sterilization device 1 according to an embodiment of the present invention. Additionally, Figure 2 This is an exploded view of the constituent components of the fluid sterilization device 1. The fluid sterilization device 1 is a device that sterilizes fluid flowing in a flow path by irradiating it with ultraviolet light, and is used in water storage tanks such as ice makers, water delivery pipes, water heaters, water dispensers, circulation devices, beverage servers, etc.

[0044] like Figure 1 As shown, the outer tube 10 of the fluid sterilization device 1 consists of a main body 11, an inlet tube 12, an outlet tube 13, a retaining cap 14, a base plate 15, and a cover 16. The main body 11, inlet tube 12, and outlet tube 13 are made of stainless steel, but these components can be replaced with other metal or resin materials depending on the purpose. In addition, considering heat dissipation, the retaining cap 14, base plate 15, and cover 16 are made of aluminum.

[0045] The fluid constituting the target for sterilization enters the main body 11 through the inlet pipe 12 and flows out to the outside of the outer pipe 10 through the outlet pipe 13. The outlet pipe 13 is a straight pipe type and is coaxially arranged with the inlet pipe 12. Therefore, compared with the so-called L-type fluid sterilization device, it has the advantage of being easier to assemble into various systems.

[0046] A light source is provided on a substrate (not shown) mounted on the base plate 15 to irradiate the fluid passing through the main body 11 with ultraviolet light. As a result, the fluid is sterilized, and the sterilized fluid finally flows out from the outlet pipe 13.

[0047] like Figure 2 As shown, an inner tube 20 is housed inside the main body 11 of the outer tube 10. The inner tube 20 is composed of a cylindrical portion 21, an outlet tube 22, and a cap 23. It should be noted that the components constituting the inner tube 20 are preferably made of resin (e.g., PTFE) that diffuses and reflects ultraviolet light.

[0048] In this embodiment, the cylindrical portion 21 is open at both ends along its axial direction. Furthermore, six radially penetrating slits 21a are provided at one end of the cylindrical portion 21 (left end in the figure). The outer diameter of the cylindrical portion 21 is smaller than the inner diameter of the main body 11 of the outer tube 10, thus forming a gap (annular space) between the main body 11 and the inner tube 20. Fluid flows through this gap and into the interior of the cylindrical portion 21 from the slits 21a. Additionally, the other end of the cylindrical portion 21 (right end in the figure) is sealed with an O-ring (not shown) by a cap 23.

[0049] The cylindrical portion 21 has a radially penetrating opening 21b, through which an outlet pipe 22 is installed. After installation, the outlet pipe 22 protrudes radially from the cylindrical portion 21. Furthermore, the outlet pipe 22 is connected to the outflow pipe 13 inside the outer pipe 10. Therefore, fluid flowing into the interior of the cylindrical portion 21 flows out through the outlet pipe 22 from the outflow pipe 13 to the exterior of the outer pipe 10.

[0050] The number of the aforementioned cutouts 21a can be appropriately changed, but it is preferable that they are arranged in pairs symmetrically with respect to the central axis of the inner tube 20. By arranging them in this way, the fluid flowing into the gap between the outer tube 10 and the inner tube 20 can flow into the interior of the cylindrical portion 21 equally, thereby achieving uniform flow velocity distribution.

[0051] The retaining cap 14 houses an ultraviolet light transmission window 30 and a reflector 40. Additionally, the base plate 15 and the cover 16 are fixed to the retaining cap 14 with screws. The light source (not shown) is mounted on a substrate (not shown) on the base plate 15. This substrate is preferably a copper or aluminum substrate with excellent heat dissipation.

[0052] The light source (light source 55, described later) is a UV-LED, emitting ultraviolet light with wavelengths that have a bactericidal effect or can decompose chemical substances. It should be noted that the wavelength range of the ultraviolet light is 240–380 nm.

[0053] The ultraviolet light transmission window 30 is a circular quartz plate that allows ultraviolet light to pass through. It contacts the end face of the cylindrical portion 21 with the notch 21a, thereby sealing that end. Specifically, an O-ring (not shown) for sealing is installed around the ultraviolet light transmission window 30, and the outer circumference of the O-ring presses against the inner circumferential surface of the retaining cap 14. The diameter of the ultraviolet light transmission window 30 preferably exceeds the outer circumference of the inner tube 20 (cylindrical portion 21).

[0054] The reflector 40 is a circular PTFE plate that reflects ultraviolet light and is positioned on the side of the ultraviolet light transmission window 30 opposite to the inner tube 20. A recess is formed in the center of the reflector 40, and an opening for ultraviolet light to be emitted is located in the center of the recess. The ultraviolet light is reflected on the surface of the reflector 40, irradiating the fluid flowing into the interior of the cylindrical section 21.

[0055] In addition, ultraviolet light can also be guided through the reflective gap (annular space) of the reflector plate 40 by the window 30. Therefore, the fluid passing through this gap can also be sterilized, thereby improving the sterilization efficiency.

[0056] As described below, the reflector 40 has an opening 40a for an illuminance sensor. The illuminance sensor detects the illuminance of ultraviolet light through the opening 40a, thus enabling it to determine whether the fluid has been exposed to ultraviolet light.

[0057] Figure 3 This is a plan view of the fluid sterilization device 1 viewed from one side of the cover 16. The cover 16 has a central opening 16a and four peripheral openings 16b. Opening 16a is for leading out wiring for the light source and illuminance sensor. Opening 16b is a threaded hole for fixing a substrate to which the light source is mounted.

[0058] then, Figure 4 express Figure 3 A cross-sectional view of the fluid sterilization device 1 along line IV-IV.

[0059] As shown in the figure, the inner tube 20 is housed inside the outer tube 10. Specifically, the cap 23 of the inner tube 20 contacts the end (right end in the figure) of the main body 11 of the outer tube 10, and an annular space 28 exists on the outer periphery of the inner tube 20. In addition, the outlet tube 22 of the inner tube 20 is embedded inside the outlet tube 13.

[0060] A cutout 21a is formed at the end of the cylindrical portion 21 (on the side of the ultraviolet light transmission window 30). Therefore, the fluid flowing in from the inlet pipe 12 will necessarily pass near the light source 55, and the ultraviolet light can reliably irradiate the fluid. Alternatively, a radially penetrating connecting hole can be formed at the end of the cylindrical portion 21 closer to the ultraviolet light transmission window 30 than the axis of the inlet pipe 12 and the outlet pipe 13, thereby replacing the cutout 21a.

[0061] Ultraviolet light emitted from the light source 55 on the substrate 50 illuminates the cylindrical portion 21 through the ultraviolet light transmission window 30, and a portion of the ultraviolet light is reflected by the reflector 40. The ultraviolet light illuminates the interior of the cylindrical portion 21, which constitutes the sterilization treatment space, and the annular space 28 through the ultraviolet light transmission window 30.

[0062] In addition, an ultraviolet light illuminance sensor 45 is mounted on the substrate 50. Furthermore, the illuminance sensor 45 is disposed on the back side of the opening 40a of the reflector 40. Therefore, ultraviolet light enters through the opening 40a and is detected by the illuminance sensor 45.

[0063] The illuminance value detected by the illuminance sensor 45 is used to determine the intensity of the light source 55. For example, if the intensity of ultraviolet light falls below a predetermined threshold, the user can determine that it is time to replace the light source 55.

[0064] Figure 5 This is a plan view of the fluid sterilization device 1 viewed from the front side. The flow of fluid in the fluid sterilization device 1 will be explained below. Furthermore, Figure 6 express Figure 5 VI-VI sectional view of the fluid sterilization device 1, Figure 7 express Figure 5 VII-VII sectional view of the fluid sterilization device 1.

[0065] like Figure 6 As shown, the fluid flowing in from the inlet pipe 12 first reaches the annular space 28, and then passes through the outer periphery of the inner pipe 20 (cylindrical portion 21). Then, it enters the interior of the cylindrical portion 21 through the six cutouts 21a present at the end of the cylindrical portion 21.

[0066] Then, as Figure 7As shown, the fluid moves toward the opening 21b of the cylindrical section 21 and flows out through the outlet pipe 13 via the outlet pipe 22. Although the fluid sterilization device 1 is a straight pipe type, the fluid changes direction while moving forward inside the outer pipe 10. Therefore, uniform flow velocity distribution can be achieved. Since the fluid is continuously irradiated with ultraviolet light from the time it enters the annular space 28 until it reaches the outlet pipe 22, sterilization of the fluid can be reliably performed.

[0067] Next, refer to Figure 8A , Figure 8B The simulation results of the velocity distribution of the fluid at a flow rate of 7 [L / min] are explained.

[0068] Figure 8A (a) shows Figure 3 The flow velocity distribution in the IV-IV cross-sectional view of the fluid sterilization device 1. Additionally, Figure 8A (b) Figure 8A (c) shows respectively Figure 5 VI-VI sectional view of the fluid sterilization device 1 Figure 5 The flow velocity distribution in the VII-VII cross-sectional view of the fluid sterilization device 1.

[0069] according to Figure 8A (a) Figure 8A (b) It can be seen that the fluid velocity is relatively slow (0.2–0.4 m / s) between the inflow pipe 12 and the annular space 28, and the fluid velocity increases instantaneously (0.6–0.8 m / s) at the point where it flows from the cut-out portion 21a into the interior of the cylindrical portion 21. Furthermore, according to… Figure 8A (c) It can be seen that the flow velocity inside the cylindrical section 21 is relatively slow (0.2 to 0.6 [m / s]), but after reaching the outlet pipe 13, the flow velocity increases again (0.6 to 1.0 [m / s]).

[0070] Figure 8B (a) shows Figure 6 The flow velocity distribution at the horizontal cross-section H of the fluid sterilization device 1. Additionally, Figure 8B (b) Figure 8B (c) shows respectively Figure 6 The velocity distribution at the inclined section X and the velocity distribution at the inclined section Y of the fluid sterilization device 1. According to... Figure 8B As can be seen from (a) to (c), the flow velocity of the fluid increases at the point where it flows from the cut-out portion 21a into the interior of the cylindrical portion 21, and the flow velocity is slow inside the cylindrical portion 21 (especially near the center).

[0071] Finally, refer to Figure 9A , Figure 9BThe results of the simulation of ultraviolet light illuminance distribution when the fluid flow rate is 7 [L / min] are explained.

[0072] Figure 9A (a) shows Figure 3 Illumination distribution in cross-sectional view IV-IV of the fluid sterilization device 1. Additionally, Figure 9A (b) Figure 9A (c) shows respectively Figure 5 VI-VI sectional view of the fluid sterilization device 1 Figure 5 Illumination distribution in sectional view VII-VII of fluid sterilization device 1.

[0073] according to Figure 9A As shown in (a) and (c), the illuminance is highest (0.8–20 mW / cm²) near the end of the cylindrical portion 21 with the notch 21a. 2 The closer to the direction of the outflow pipe 13, the lower the illuminance (0.6–0.8 mW / cm²). 2 ). In addition, according to Figure 9A (b) It can be seen that the illuminance at the center of the cylindrical part 21 is the highest (0.8~20 [mW / cm²)). 2 The closer to the inner wall of the cylindrical part 21, the lower the illuminance (0.6–0.8 mW / cm²). 2 ).

[0074] Figure 9B (a) shows Figure 6 The illuminance distribution of the horizontal cross-section H of the fluid sterilization device 1. Additionally, Figure 9B (b) Figure 9B (c) shows respectively Figure 6 Illuminance distribution of the oblique section X and oblique section Y of the fluid sterilization device 1.

[0075] according to Figure 9B As can be seen from (a) to (c), the illuminance is highest near the end with the cut portion 21a, and decreases as it approaches the outflow pipe 13. Furthermore, it can be observed that the illuminance in the annular space 28 is relatively low (0.2–0.4 mW / cm²). 2 However, ultraviolet light entered the annular space 28.

[0076] As described above, although the fluid sterilization device 1 in this embodiment is a straight tube and a small device, it incorporates a design to suppress flow velocity internally, thereby achieving uniform flow velocity distribution. The fluid passes near the light source 55 that emits ultraviolet light, thus improving the sterilization efficiency of the fluid.

[0077] The above embodiment is only one example and can be appropriately modified according to different applications. Depending on the application, the flow rate of the cylinder of the fluid sterilization device 1 varies, therefore the size and shape of the cylinder can be changed. Furthermore, in the fluid sterilization device 1, the inlet pipe 12 and the outlet pipe 13 can also be used horizontally in a horizontal orientation.

[0078] Symbol Explanation

[0079] 1… Fluid sterilization device, 10… Outer tube, 11… Main body, 12… Inflow tube, 13… Outflow tube, 14… Holding cap, 15… Base plate, 16… Cover, 16a, 16b… Opening, 20… Inner tube, 21… Cylindrical part, 21a… Cut-out part, 21b… Opening, 22… Outflow tube, 23… Cap, 28… Annular space, 30… Ultraviolet light transmission window, 40… Reflector, 40a… Opening, 45… Illuminance sensor, 50… Substrate, 55… Light source.

Claims

1. A fluid sterilization device, characterized in that, have: A cylindrical inner tube with one end open in the axial direction, the inner tube being composed of a cylindrical part, an outlet tube and a cap, with a radially penetrating cut provided at one end of the cylindrical part; An outer tube having a main body portion that houses the inner tube; An inflow pipe, which protrudes radially from the main body, is provided for the inflow of fluid; An outflow pipe, which protrudes radially from the main body and is coaxially arranged with the inflow pipe, allows the fluid to flow out. as well as A light source, through an ultraviolet light transmission window at the end of the outer tube sealed at one end, irradiates the fluid passing through the interior of the inner tube with ultraviolet light. The inner tube is housed within the main body in such a way that it forms an annular space for fluid flow between the inner wall of the main body and the outer wall of the cylindrical part. An opening extending radially through the cylindrical portion and an outlet pipe disposed at the opening are provided at a position corresponding to the outflow pipe. The outlet pipe protrudes radially from the cylindrical portion and is connected to the outflow pipe inside the outer tube. The cutout is located on the side of the ultraviolet light transmission window, and the cutouts are arranged in pairs in symmetrical positions relative to the central axis of the inner tube. A flow path is formed in which the fluid flows in the order of the inlet pipe, the annular space, the cut-out portion, the interior of the cylindrical portion, the outlet pipe, and the outlet pipe. A reflector plate that reflects the ultraviolet light is disposed on the side of the ultraviolet light transmission window opposite to the inner tube. The ultraviolet light transmission window guides the ultraviolet light into the annular space by means of the reflection of the reflector plate.

2. The fluid sterilization device according to claim 1, characterized in that, An illuminance sensor is provided on the back side of the reflector, and the reflector has an opening through which the illuminance sensor detects the illuminance of the ultraviolet light.

3. The fluid sterilization device according to claim 1 or 2, characterized in that, The inner tube is made of resin material.

4. A fluid sterilization device, characterized in that, have: A cylindrical inner tube with one end open in the axial direction, the inner tube is composed of a cylindrical part, an outlet tube and a cap, and a connecting hole that passes through in the radial direction is provided at one end of the cylindrical part; An outer tube having a main body portion that houses the inner tube; An inflow pipe, which protrudes radially from the main body, is provided for the inflow of fluid; An outflow pipe, which protrudes radially from the main body and is coaxially arranged with the inflow pipe, allows the fluid to flow out. as well as A light source, through an ultraviolet light transmission window at the end of the outer tube sealed at one end, irradiates the fluid passing through the interior of the inner tube with ultraviolet light. The inner tube is housed within the main body in such a way that it forms an annular space for fluid flow between the inner wall of the main body and the outer wall of the cylindrical part. An opening extending radially through the cylindrical portion and an outlet pipe disposed at the opening are provided at a position corresponding to the outflow pipe. The outlet pipe protrudes radially from the cylindrical portion and is connected to the outflow pipe inside the outer tube. The connecting holes are located closer to the end of the cylindrical portion of the ultraviolet light transmission window than the axes of the inlet and outlet pipes, and the connecting holes are arranged in pairs symmetrically with respect to the central axis of the inner pipe. A flow path is formed in which the fluid flows in the order of the inlet pipe, the annular space, the connecting hole, the interior of the cylindrical section, the outlet pipe, and the outlet pipe. A reflector plate that reflects the ultraviolet light is disposed on the side of the ultraviolet light transmission window opposite to the inner tube. The ultraviolet light transmission window guides the ultraviolet light into the annular space by means of the reflection of the reflector plate.

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