Fluid sterilization device

Abstract

The liquid sterilization device (10) includes: an outer tube (22) that allows the fluid to be sterilized to flow axially from one end to the other; a rectifier plate (42) having a plurality of tapered holes (43) whose diameter increases axially from one end to the other; and a light source (67) that irradiates ultraviolet light onto the sterilization treatment space (39) that is on the other end of the rectifier plate (42).

Description

Technical Field

[0001] This invention relates to a fluid sterilization device that sterilizes fluid flowing in a tubular passage by irradiating it with ultraviolet light. Background Technology

[0002] Patent Document 1 discloses a fluid sterilization device that sterilizes fluid flowing within a tubular passage by irradiating it with ultraviolet light. In this fluid sterilization device, a rectifier plate with multiple through holes is disposed on the inlet side of the tubular passage, and the fluid flows in a rectified state within the sterilization treatment space, thereby suppressing uneven irradiation when the fluid flowing within the tubular passage is irradiated with ultraviolet light.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-92856 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In the rectifier plate of Patent Document 1, the through-hole in the radial center of the rectifier plate has a larger diameter than the through-hole in the peripheral portion. This promotes the homogenization of the velocity distribution of the fluid downstream of the rectifier plate in the radial direction. Furthermore, all the through-holes in the rectifier plate of Patent Document 1 are cylindrical holes.

[0008] On the other hand, a technical solution has been proposed that involves arranging two rectifiers spaced apart on the upstream and downstream sides in the axial direction. In this case, the upstream rectifier has multiple cylindrical first through holes at a radially central location, while the downstream rectifier has multiple cylindrical second through holes with a diameter larger than the first through holes distributed across its entire surface. This allows for axial rectification of the fluid flowing from the inlet into the tubular passage over a relatively short length.

[0009] The purpose of this invention is to provide a fluid sterilization device that can achieve high rectification function through a rectifier plate, thereby further miniaturizing it in the axial direction.

[0010] Methods for solving problems

[0011] The fluid sterilization device of the present invention comprises:

[0012] A tube body having a tubular passage that allows fluid flowing in from an inlet at one end of the axial direction to flow along the axial direction to an outlet at the other end of the axial direction.

[0013] A rectifier plate having a plurality of tapered holes with a diameter increasing from one end to the other end in the axial direction, the rectifier plate being disposed within the tubular passage, dividing the tubular passage into an inlet space at one end and a sterilization treatment space at the other end; and,

[0014] The light source irradiates the sterilization treatment space with ultraviolet light.

[0015] The effects of the invention

[0016] According to the present invention, by forming the through hole of the rectifier plate into a tapered hole with a diameter increasing in the direction of fluid flow in the tubular passage, a high rectification function can be achieved. As a result, the axial dimension of the fluid sterilization device can be reduced. Attached Figure Description

[0017] Figure 1A This is a 3D diagram of a liquid sterilization device.

[0018] Figure 1B This is the front view of the liquid sterilization device.

[0019] Figure 2 This is a longitudinal sectional view of the liquid sterilization device.

[0020] Figure 3 This is an enlarged view of the end of the liquid sterilization device on the light source side.

[0021] Figure 4A This is a diagram showing the rectifier plate viewed axially from the other end.

[0022] Figure 4B This is a three-dimensional view of the rectifier plate viewed from the other end along the direction inclined to the axial direction.

[0023] Figure 5 This is a diagram showing the direction of the cross-section.

[0024] Figure 6A Is Figure 5 The Ac-Ac view shows a diagram of the flow rate distribution within the liquid sterilization device in Comparative Example 1.

[0025] Figure 6B Is Figure 5 The Ac-Ac view shows a diagram of the flow rate distribution within the liquid sterilization device in Comparative Example 2.

[0026] Figure 6C Is Figure 5 The Ac-Ac view shows a diagram of the flow rate distribution within the liquid sterilization device in Comparative Example 3.

[0027] Figure 6D Is Figure 5The Ac-Ac cross-section shows a diagram of the flow rate distribution within the liquid sterilization device in the embodiment.

[0028] Figure 7A Is Figure 5 The flow rate distribution within the liquid sterilization device of Comparative Example 1 is shown in the Bc-Bc view section.

[0029] Figure 7B Is Figure 5 The flow rate distribution within the liquid sterilization device of Comparative Example 2 is shown in the Bc-Bc view section.

[0030] Figure 7C Is Figure 5 The flow rate distribution within the liquid sterilization device of Comparative Example 3 is shown in the Bc-Bc view section.

[0031] Figure 7D Is Figure 5 The flow rate distribution within the liquid sterilization device in the embodiment is shown in the Bc-Bc view section.

[0032] Figure 8 This is a diagram showing the other rectifier plate viewed axially from the other end.

[0033] Figure 9 This is an explanatory diagram illustrating the preferred range of the cone angle for a tapered hole. Detailed Implementation

[0034] Hereinafter, several embodiments of the present invention will be described. The present invention is not limited to these embodiments. It should be noted that the same reference numerals are used for common constituent elements among the various embodiments, and descriptions of constituent elements for which the same reference numerals have been described in previous embodiments will be omitted in later embodiments.

[0035] (structure)

[0036] Figure 1A This is a three-dimensional view of the liquid sterilization device 10. Figure 1B This is a front view of the liquid sterilization device 10. Figure 2 This is a longitudinal sectional view of the liquid sterilization device 10. Figure 3 This is an enlarged view of the end of the liquid sterilization device 10 on the side of the light source section 12.

[0037] The liquid sterilization device 10 includes a housing 11, a light source 12, an inlet 13, and an outlet 14. The inlet 13 and the outlet 14 are integrally formed with the housing 11. Figure 1B As shown, the liquid sterilization device 10 is typically configured such that its axial direction is aligned with the vertical direction with the light source 12 as the upper side (longitudinal configuration).

[0038] The liquid sterilization device 10 is an example of a fluid sterilization device that sterilizes water, which is also a fluid. Examples of liquid sterilization devices 10 include water storage tanks in ice makers, water supply pipes, water heaters, water dispensers, circulation devices (cooling water for refrigeration units), and beverage dispensers.

[0039] Water sterilized using the liquid sterilization device 10 is typically used for drinking. It should be noted that sterilization in the circulation system is performed to prevent the following: if bacteria proliferate in the circulating water, the viscosity of the circulating water increases, leading to a loss of power.

[0040] For connection to a tube (not shown) within the device equipped with the liquid sterilization device 10, the inlet 13 and outlet 14 are provided with threaded grooves on their periphery. Figure 1B The liquid sterilization device 10 uses ultraviolet light from the light source 12 to sterilize water. The water flows axially from one side (one end side) of the inlet 13 to one side (the other end side) of the outlet 14 in a tubular passage formed in the housing 11 and consisting of the inlet side space 38 and the sterilization treatment space 39.

[0041] The light source 12 is mounted on the housing 11 at the other end of the liquid sterilization device 10, with its central axis aligned with the central axis of the housing 11. The inlet 13 is provided axially at one end of the housing 11. The outlet 14 is provided radially protruding from the other end of the housing 11 at a predetermined distance away from one end, on the side of the housing 11.

[0042] The housing portion 11 has an inner tube 21 and an outer tube 22 arranged coaxially. Both the inner tube 21 and the outer tube 22 are straight tubes. An inlet portion 13 and an outlet portion 14 are integrally provided on the outer tube 22. An inlet port 34 and an outlet port 35 are respectively divided on the inner circumferential side of the inlet port 13 and the outlet port 14, connecting the inside and outside of the outer tube 22.

[0043] The inner tube 21 has an inner tube component 17 at one end and a tube component 18 at the other end, which are axially engaged with each other from one end and the other end by the tightening force of the retaining nut 47 described later. The inner tube 21 is inserted into the outer tube 22 through an opening at the other end of the outer tube 22. The inner tube component 17 at one end and the tube component 18 at the other end are open at both ends in the axial direction.

[0044] The other end tube component 18 has a small-diameter portion 25 on one end and a large-diameter portion 26 on the other end in the axial direction. An annular space 29 is formed between the inner circumference of the outer tube 22 and the outer circumference of the small-diameter portion 25. A stepped portion is formed at the boundary between the small-diameter portion 25 and the large-diameter portion 26. This stepped portion is located axially on one end side closer to the outlet 35. Thus, the outlet 35 is not covered by the large-diameter portion 26 and is entirely exposed in the annular space 29.

[0045] In this embodiment, the stepped portion rises from the small diameter portion 25 perpendicular to the axial direction of the inner pipe 21, that is, parallel to the radial direction of the inner pipe 21. A conical stepped portion can also be used instead of a vertical stepped portion, thereby allowing the water flow to smoothly change from the annular space 29 to the direction of the guide outlet 35.

[0046] The periphery of the rectifier plate 42 is fitted into the annular groove 20, which is formed on the inner circumference of the joint 19 between the inner tube component 17 on one end and the tube component 18 on the other end. The rectifier plate 42 is clamped by the mutual engagement forces from the inner tube component 17 on one end and the tube component 18 on the other end from both axial sides. This engagement force is generated by the axial tightening force of the fixing nut 47, which will be described later.

[0047] The rectifier plate 42 divides the tubular passage on the inner circumference side, which is divided by the inner tube 21, into an inlet space 38 on one end and a sterilization treatment space 39 on the other end. Figure 4A and Figure 4B These are images showing the rectifier plate 42 viewed from the opposite side of the axial direction and from the opposite side of the axial direction at an angle, respectively. Figure 2 , Figure 4A and Figure 4B In the rectifier plate 42, there are multiple tapered holes 43 extending along the axial direction. Each tapered hole 43 has a circular upstream opening 44a at one end along the axial direction and a circular downstream opening 44b at the other end. The diameter of the upstream opening 44a is smaller than the diameter of the downstream opening 44b. That is, the diameter of the tapered hole 43 gradually increases from one end to the other along the axial direction.

[0048] exist Figure 3 In the middle, the other end tube component 18 has a plurality of U-shaped notches 50 arranged at equal angles along the circumferential end face of the other end side in the axial direction. The peripheral part of one end side of the quartz plate 45 is embedded into the stepped part of the inner circumference of the other end of the outer tube 22 and abuts against the circumferential end face of the other end tube component 18. The peripheral part of the other end side of the quartz plate 45 abuts against an annular spacer 56.

[0049] The circuit board 57 is inserted into the through hole of the fixing nut 47, with the quartz plate 45 side as the surface, and a light source 67 is located at the center of the surface. The heat sink 58 is inserted into the through hole of the fixing nut 47 at one end in the axial direction, and the flange of the heat sink 58 at the other end in the axial direction abuts against the end face of the fixing nut 47, and is fixed to the end face of the fixing nut 47 by a plurality of screws 60.

[0050] The retaining nut 47 is fixed to the housing portion 11, which is a tube body, by screwing into a threaded groove formed on the outer periphery of the other end of the outer tube 22 in the axial direction. During this engagement, the retaining nut 47 moves axially from one end to the other, axially tightening the inner tube component 17 and the tube component 18 housed within the outer tube 22 to form an engagement. Thus, the inner tube component 17 and the tube component 18 engage with each other and axially clamp the periphery of the rectifier plate 42 within the annular groove 20.

[0051] (bactericidal effect)

[0052] Water (not shown), the fluid to be sterilized, is pumped into inlet 34 by a pump (not shown). Then, the water flows from inlet 34 into inlet-side space 38, where it diffuses radially toward inner pipe 21 due to the increase in cross-sectional area of ​​the passage.

[0053] Then, water enters the sterilization treatment space 39 through the conical hole 43 of the rectifier plate 42. As the water passes through the conical hole 43, it diffuses radially in a direction perpendicular to the axial direction, and after being ejected from the conical hole 43, it exits at a cone angle θ with respect to the conical hole 43. Figure 9 The corresponding diffusion angle diffuses. As a result, on the other end side (downstream side) of the rectifier plate 42, the water jets sprayed from the adjacent conical holes 43 into the sterilization treatment space 39 come into contact with each other at an appropriate angle of inclination, suppressing radial diffusion and becoming rectified parallel to the axial direction.

[0054] Light source 67 irradiates the water in the sterilization treatment space 39 with ultraviolet light from the other end of the axial direction via quartz plate 45. This sterilizes bacteria and other contaminants mixed in the water. Upon contact with quartz plate 45, the water's direction changes from axial to radially outward, passing through notch 50 and entering the annular space 29. In the annular space 29, the water flows axially from one end to the other, opposite to the flow in the sterilization treatment space 39. At outlet 35, the water flow direction changes to radially outward and flows out of the liquid sterilization device 10.

[0055] The notch 50 connects the upper end of the sterilization treatment space 39 to the upper end of the annular space 29, thus preventing contamination of the upper parts of the sterilization treatment space 39 and the annular space 29. Figure 1BThe upper part of the vertical configuration can cause air accumulation and water retention.

[0056] Ultraviolet light intensity decreases significantly when it passes through air, reducing its bactericidal effectiveness. Furthermore, if water stagnates instead of flowing within the sterilization chamber 39, this stagnant water becomes residual water within the sterilization chamber 39 after the liquid sterilization device 10 has finished operating. When the non-operating time is prolonged, bacteria will multiply in this residual water. Therefore, before restarting operation, sterilizing water can only be used after the residual water containing bacteria has been drained from the liquid sterilization device 10.

[0057] In the liquid sterilization device 10, the notch 50 at the other end of the other side pipe component 18 can prevent air accumulation and fluid retention in the housing 11, thus preventing the reduction of the sterilization power of the liquid sterilization device 10 and the generation of residual water.

[0058] (Flow velocity distribution map)

[0059] Figure 5 This is a diagram showing the direction of the cross-section. Figure 6A , Figure 6B , Figure 6C and Figure 6D They are in Figure 5 The Ac-Ac view shows the flow rate distribution in the fluid sterilization apparatus of Comparative Example 1, Comparative Example 2, Comparative Example 3 and the liquid sterilization apparatus 10 of the embodiment. Figure 7A , Figure 7B , Figure 7C and Figure 7D They are in Figure 5 The flow rate distribution in the fluid sterilization apparatus of Comparative Example 1, Comparative Example 2, Comparative Example 3 and the liquid sterilization apparatus 10 of the embodiment is shown in the Bc-Bc view cross section.

[0060] The flow velocity distributions in these graphs are the result of simulations conducted by the inventors, representing flow velocity through multiple stages. In these graphs, the whiter the area, the higher the flow velocity.

[0061] Comparative Example 1 is a velocity distribution diagram without a rectifier. Comparative Example 2 is a velocity distribution diagram with two rectifiers. In Comparative Example 2, both rectifiers have cylindrical through holes in their axial direction; the diameter of the cylindrical hole in the upstream rectifier is smaller than the diameter of the cylindrical hole in the downstream rectifier. Comparative Example 3 is an example with one rectifier, where the through hole is a cylindrical hole. Compared to the above comparative examples, Figure 6D and Figure 7D The liquid sterilization device 10 of the embodiment includes a flow rectifier 42. It should be noted that the cone angle θ of the conical hole 43 of the flow rectifier 42 is... Figure 9 The value is set to 14°.

[0062] In Comparative Example 1 ( Figure 6A and Figure 7A Comparative Example 3 Figure 6C and Figure 7C In Comparative Example 2, the white area extends longer to one side at the other end, whereas in Comparative Example 3... Figure 6B and Figure 7B In the tubular passage, the white area is shorter. A smaller white area in the tubular passage indicates a higher rectification state. This is evident in the liquid sterilization device 10 of the embodiment. Figure 6D and Figure 7D In Comparative Example 2, the axial position of the fluid ejected from a rectifier plate after ejection, which becomes a stable rectified state, is approximately the same as that in Comparative Example 2. Figure 6B and Figure 7B The downstream rectifier plate is in the same axial position as the liquid sterilizer 10. Therefore, by using the rectifier plate 42 of the liquid sterilizer 10, the same rectification effect as when using two rectifier plates with different apertures can be obtained, and the axial size of the liquid sterilizer 10 can be reduced.

[0063] The inventors further obtained the following insights through simulation experiments. In Comparative Example 2 (an example using two rectifiers), when the length of the rectifier chamber (the length of the portion upstream of the rectifier) ​​was reduced from 10 mm to 5 mm, the effect of homogenizing the flow velocity distribution weakened. Compared to Comparative Example 2, when using the liquid sterilization device 10 of the embodiment, it was determined that even when the length of the rectifier chamber (the length of the upstream portion of the rectifier, equivalent to the length of the inner tube component 17 at one end) was reduced from 10 mm to 5 mm, the effect of homogenizing the flow velocity distribution could be maintained.

[0064] Moreover, in Figure 6D and Figure 7D In the middle, the cone angle θ of the conical hole 43 ( Figure 9 The cone angle is set to 14°, but even when the cone angle θ is increased to 18.4°, roughly the same effect can be achieved as when the cone angle θ is 14°. For the preferred range of cone angle θ, please refer to the following... Figure 9 Please provide an explanation.

[0065] (Range of cone angle θ)

[0066] Figure 9 This is an explanatory diagram regarding the preferred range of the cone angle θ of the tapered aperture 43. It should be noted that the cone angle θ of the tapered aperture 43 is defined as: the cross-section of the rectifier 42 when it is cut with a plane containing the central axis of the tapered aperture 43 (by...). Figure 9 In the cross-section shown in the figure, the angle between the side edge line of the tapered hole 43 and the central axis of the rectifier plate 42. It should be noted that the direction of the central axis of the rectifier plate 42 is parallel to the axis of the liquid sterilization device 10.

[0067] Figure 9 The definitions of the symbols in the code are as follows.

[0068] tl: Thickness of rectifier plate 42 (= Dimension of rectifier plate 42 in the direction of the central axis)

[0069] di: Diameter of the upstream opening 44a

[0070] do: Diameter of downstream opening 44b

[0071] Fw: Direction of mainstream water flow in a tubular passage

[0072] Φa: Diameter of rectifier plate 42

[0073] Ra: A specified value less than 1 (e.g., 0.65)

[0074] To define the preferred range for the cone angle θ, we import the following equation 1.

[0075] Equation 1: (2·tl) / (di+do)<Ra

[0076] The reason why Ra is preferably 0.65 is as follows. Consider the case where di = do on the left side of Equation 1. di = do means that a cylindrical hole is used instead of a conical hole 43. When the fluid sterilization device has only one rectifier plate, and all the through holes of the rectifier plate are cylindrical holes of equal diameter, when Ra ≥ 0.65, the rectification state on the downstream side of the rectifier plate is inappropriate, that is, the uniformity of the flow velocity distribution in the radial direction of the tubular passage is poor, and the function of the rectifier plate is insufficient. Therefore, 0.65 is selected as Ra.

[0077] It should be noted that Ra must be set to a value less than 1 because if Ra ≥ 1, the thickness of the rectifier plate is larger than the diameter of the through-hole, turning the through-hole into a throttling orifice, which would lead to a significant decrease in flow velocity. Furthermore, in order to perform its rectification function, the rectifier plate needs to have a spacer wall Wp ( Figure 9 () function.

[0078] Regarding the relationship between the cone angle θ and the parameters in Equation 1, there exists the following relationship in Equation 2.

[0079] Formula 2: tanθ=(do-di) / (2·tl)

[0080] For example, when di = 3mm, do = 4mm, and tl = 2mm, Equation 1 is satisfied, and θ = 14°. Additionally, when di = 3mm, do = 5mm, and tl = 2mm, Equation 1 is satisfied, and θ = 26.5°. It should be noted that, compared with the above... Figure 6D and Figure 7D The cone angles θ = 14° and θ = 18.4°, which are mentioned in connection, are also values ​​within the range that satisfy the conditions of Equation 1.

[0081] The preferred range of the cone angle θ is summarized, and the range of the cone angle θ derived from Equation 2 becomes the requirement for satisfying Equation 1. It should be noted that multiple tapered holes 43 must be formed on the rectifier plate 42, therefore, do must be less than Φa.

[0082] (Another rectifier board)

[0083] Figure 8 This is a view of a rectifier 72, which differs from the rectifier 42, viewed from the other end of the axial direction. The rectifier 72 has multiple tapered holes 43 that act as through holes extending axially. Figure 4A The rectifier plate 72 is divided into a central portion and a peripheral portion in the radial direction. The tapered hole 43 is formed in the central portion and the cylindrical hole 74 is formed in the peripheral portion.

[0084] When water, which is the fluid used for sterilization by the liquid sterilization device 10, flows into the inlet-side space 38 from the inlet 34, it diffuses radially. Water on the peripheral side of the inlet-side space 38 travels forward by being inhibited from radial diffusion by the inner peripheral walls of the inner tube component 17 at one end and the inner peripheral wall of the inner tube component 18 at the other end, before reaching the notch groove 50 axially. Conversely, when water on the peripheral side passes through the tapered orifice 43, the possibility of axial water flow along the inner peripheral wall of the inlet-side space 38 being obstructed by the tapered orifice 43 also increases.

[0085] Therefore, in the rectifier plate 72, the water in the central part passes through the conical hole 43 in the radial direction, and the water in the peripheral part passes through the cylindrical hole 74. Thus, the rectification effect is increased for the water in the peripheral part compared to the water passing through the conical hole 43.

[0086] Additionally, rectifier plate 42 ( Figure 4A ), Rectifier plate 72 ( Figure 8 The multiple conical holes 43 are continuous in any arrangement direction (longitudinal, transverse or inclined), and one conical hole 43 is isolated relative to the other conical holes 43, that is, in any arrangement direction, the adjacent holes are not cylindrical holes 74.

[0087] (Modified Example)

[0088] In the liquid sterilization device 10, ultraviolet light from the circuit board 57 irradiates the water, which is the fluid to be sterilized, within the sterilization treatment space 39 along the axial direction. Alternatively, the ultraviolet light source can be positioned radially outside the tube body so that the ultraviolet light of the present invention irradiates the water within the sterilization treatment space 39 from the radially outside. It should be noted that in this case, the liquid sterilization device 10 does not need to be configured with a dual structure of an inner tube 21 and an outer tube 22; the inner tube 21 can be omitted. Furthermore, the water flows directly from the outlet 35 from the sterilization treatment space 39 without passing through the annular space 29.

[0089] In the liquid sterilization device 10, the housing portion 11 forms a tube body, and the outer tube 22 forms a cylindrical component. Furthermore, an annular space 29 is formed between the outer periphery of the other end tube component 18 and the inner periphery of the outer tube 22. In this invention, the annular space 29 and the notch 50 may be omitted. In this case, the outlet 35 opens into the sterilization processing space 39 within the other end tube component 18, allowing direct communication with the sterilization processing space 39 without passing through the annular space 29.

[0090] In the liquid sterilization device 10, a quartz plate 45 is provided as a plate-shaped transmitting component. The plate-shaped transmitting component of the present invention can also be made of other materials that have specified lightfastness to ultraviolet light, can transmit ultraviolet light, and ensure strength.

[0091] Symbol Explanation

[0092] 10…Liquid sterilization device, 11…Housing part (tube body), 12…Light source part, 17…Inner tube component on one end, 18…Tube component on the other end, 19…Joint, 20…Annular groove, 21…Inner tube, 22…Outer tube (cylindrical component), 29…Annular space, 34…Inlet, 35…Outlet, 38…Inlet side space, 39…Sterilization treatment space, 42, 72…Rectifier plate, 43…Conical hole, 45…Quartz plate (plate-shaped transparent component), 47…Fixing nut, 50…Notch groove, 67…Light source, 74…Cylindrical hole.

Claims

1. A fluid sterilization apparatus, characterized by, It has: a pipe body having a tubular passage that allows fluid flowing from a flow inlet on one end side in the axial direction to flow to a flow outlet on the other end side in the axial direction; a flow regulation plate having a plurality of tapered holes with diameters increasing from the one end side to the other end side in the axial direction, the flow regulation plate being disposed in the tubular passage to divide the tubular passage into an introduction space on the one end side and a sterilization processing space on the other end side; and a light source that irradiates ultraviolet light to the sterilization processing space, the fluid flowing in the tubular passage flows through the plurality of tapered holes of the flow regulation plate from the one end side as an upstream side to the other end side as a downstream side, the plurality of tapered holes have a smaller opening diameter on the upstream side than on the downstream side.

2. The fluid sterilization device according to claim 1, wherein the pipe body has a one end side pipe member and an other end side pipe member, the one end side pipe member has the introduction space partitioned on an inner peripheral side thereof, the other end side pipe member has the sterilization processing space partitioned on an inner peripheral side thereof, is joined to the one end side pipe member in the axial direction, and clamps a peripheral edge portion of the flow regulation plate in the axial direction with an annular groove formed between the other end side pipe member and the one end side pipe member at an inner periphery of the joint.

3. The fluid sterilization device according to claim 1 or 2, wherein the flow inlet is opened to the introduction space in opposition to the flow regulation plate in the axial direction, the flow regulation plate has the plurality of tapered holes disposed at a central portion in a radial direction and a plurality of cylindrical through holes disposed at a peripheral portion in the radial direction.

4. The fluid sterilization device according to claim 2, wherein the other end side pipe member has a plurality of notch grooves in a circumferential direction at an opening peripheral edge of the other end side pipe member opened in the axial direction, the pipe body has a cylinder member coaxially disposed with the other end side pipe member, an annular space communicated with the flow outlet on an outer peripheral side being partitioned between the cylinder member and an outer periphery of the other end side pipe member, a plate-shaped transmission member for the ultraviolet light to transmit through is in contact with the opening peripheral edge of the other end side pipe member to close the opening peripheral edge, and the light source is disposed on the other end side in the axial direction with respect to the plate-shaped transmission member.

5. The fluid sterilization device according to any one of claims 1, 2, and 4, wherein in a case where a thickness of the flow regulation plate is set as tl, diameters of an upstream side opening and a downstream side opening of the tapered holes respectively as openings of the one end side and the other end side in the axial direction are set as di and do, and Ra is set as a prescribed value smaller than 1, the following relation is satisfied, (2 · tl) / (di + do) < Ra. ​

Images