Liquid Processing Nozzle

Abstract

To provide a liquid processing nozzle in which a cavitation processing part is configured extremely simply and the number of components can be reduced considerably and which is excellent in efficiency in generation of fine bubble derived from cavitation effect.SOLUTION: A cavitation processing part 5 constituted of spiral grooves circling by one round or more with an axis line O of a liquid passage as a spiral center line is formed on an inner peripheral surface of the liquid passage 2 formed in a nozzle main body 10. Some of flow of liquid supplied to the liquid passage is distributed to the cavitation processing part, and the distributed flow colliding with the inner peripheral surface of the spiral groove is guided by the spiral groove to be circled, and is sped up by centrifugal force thereof, which can enhance efficiency in generation of fine bubble by cavitation effect thereof considerably, in comparison with a squeezing mechanism such as a Venturi pipe through which liquid just flows linearly.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a liquid treatment nozzle for performing cavitation treatment on a liquid having a dissolved gas. [Background technology]

[0002] Various nozzles have been proposed that use the cavitation effect (the pressure reduction effect when water passes through at a high flow rate) to precipitate dissolved air as fine bubbles (Patent Documents 1 to 6). A typical nozzle uses a throttled section in the water flow path using a venturi or orifice, and utilizes the cavitation effect when the liquid passes through the throttled section at an increased speed (Patent Documents 1 to 6). Patent Document 7 proposes a structure in which a cylindrical member with multiple axial slits formed around its circumference is placed in the flow path, and cavitation is generated by rotating the cylindrical member in the water flow. Patent Document 8 proposes a nozzle in which a screw member is placed in the flow path at a right angle to the water flow direction, and the thread roots are used as cavitation points. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-110468 [Patent Document 2] Patent No. 6609819 [Patent Document 3] Patent No. 6579547 [Patent Document 4] Patent No. 4915962 [Patent Document 5] WO2018 / 185866 publication [Patent Document 6] Patent No. 4999996 [Patent Document 7] Japanese Patent Application Laid-Open No. 2017-136513 [Patent Document 8] Patent No. 5731650 [Non-patent literature]

[0004] [Non-Patent Document 1] NanotechJapan Bulletin Vol. 8, No. 4, 2015, Special Feature Collabo Nanotechnology No. 4 "Analysis of nanobubbles in nanobubble water" Summary of the Invention [Problem to be solved by the invention]

[0005] The nozzles using Venturi or similar throttle mechanisms disclosed in Patent Documents 1 to 6 have limitations in achieving the flow velocity required to obtain a sufficient cavitation effect (pressure reduction effect) solely through the velocity-increasing effect of the throttle section, resulting in the problem of being unable to ensure sufficient bubble refinement and generation volume. Furthermore, excessively reducing the cross-sectional area of ​​the throttle section to increase the flow velocity leads to increased pressure loss, resulting in insufficient water flow force through the nozzle and an excessive increase in supply water pressure.

[0006] On the other hand, configurations such as those in Patent Documents 7 and 8, in which a cylindrical member or a screw member is placed inside the flow path to promote the cavitation effect, lead to an increase in the number of parts and a more complicated internal structure of the nozzle, and also have the problem of being prone to increased pressure loss due to the placement of extra members inside the flow path.

[0007] The object of the present invention is to provide a liquid processing nozzle that has an extremely simple structure for the cavitation processing section, which allows for a significant reduction in the number of parts, and which has excellent efficiency in generating fine bubbles derived from the cavitation effect. [Means for solving the problem]

[0008] The present invention relates to a liquid processing nozzle that is incorporated into a flow path through which a liquid containing dissolved gas flows, and that reduces the pressure and precipitates the dissolved gas by cavitating the liquid.In order to solve the above-mentioned problems, a through-type liquid flow path is formed in which a liquid inlet opens at one end face of the nozzle body and a liquid outlet opens at the other end face, and at least a portion of the axial direction of the inner surface of the liquid flow path is made into a cavitation processing device in which a spiral groove of at least one revolution is engraved with the axis as the spiral center line, and a portion of the liquid flow supplied to the liquid flow path is distributed to the spiral groove of the cavitation processing device, and the distributed liquid is swirled within the spiral groove while accelerating, so that the internal space of the spiral groove, which is reduced in pressure due to the increased liquid speed, becomes a cavitation region and the dissolved gas is precipitated under reduced pressure. [Effects of the Invention]

[0009] According to the liquid treatment nozzle configuration of the present invention, a cavitation treatment device is formed on the inner circumferential surface of a liquid flow path formed in the nozzle body, comprising a spiral groove with one or more revolutions around the axis of the flow path as the spiral centerline. A portion of the liquid flow supplied to the liquid flow path is distributed to the spiral groove of the cavitation treatment device. The distributed flow that collides with the inner circumferential surface of the spiral groove is guided by the spiral groove and swirls, accelerating due to the resulting centrifugal force. This centrifugal force swirling effect enhances the liquid velocity within the internal space of the spiral groove, resulting in a cavitation effect that significantly improves the efficiency of microbubble generation compared to throttle mechanisms that simply allow liquid to flow linearly, such as Venturi tubes. Furthermore, while flow loss near the inner circumferential surface of a liquid flow path is typically large due to wall friction, the configuration of the liquid treatment nozzle of the present invention increases the flow velocity near the inner circumferential surface of the cavitation treatment device due to the formation of a swirling flow, thereby minimizing pressure loss when the liquid treatment nozzle is inserted into the flow path.

[0010] In other words, the liquid treatment nozzle of the present invention has a spiral groove formed on the inner surface of the liquid flow path that exerts a remarkable cavitation effect based on the centrifugal force swirling effect, so that despite its simple configuration, it is able to efficiently generate fine bubbles with performance equal to or better than that of a liquid treatment nozzle that has a cavitation treatment section formed from a separate part such as a screw member. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are front and bottom views showing an example of a tap water treatment device incorporating a liquid treatment nozzle of the present invention; [Figure 2] FIG. 2 is a front view showing an example of a usage form of the tap water treatment device of FIG. 1. [Figure 3] 2 is a plan view and a front cross-sectional view of the tap water treatment device of FIG. 1. [Figure 4] 1 is a plan view and a front cross-sectional view of a liquid processing nozzle according to the present invention; [Figure 5] FIG. 5 is an enlarged front cross-sectional view of a main part of FIG. 4. [Figure 6] An enlarged view of the cross-sectional shape of the spiral groove. [Figure 7] FIG. 5 is a diagram illustrating the formation of a swirling flow in the cavitation treatment section of the liquid treatment nozzle of FIG. 4. [Figure 8] The first diagram explains the principle of swirling flow formation. [Figure 9] The second diagram explaining the principle of swirling flow formation [Figure 10] A diagram explaining how microbubbles are generated by the swirling flow generated in the cavitation treatment section. [Figure 11] FIG. 1 is a diagram illustrating how gas from a gas introduction passage communicating with the upstream half section of the cavitation treatment section is pulverized by a swirling flow. [Figure 12] FIG. 1 is a diagram illustrating how gas from a gas introduction passage communicating with the downstream half section of the cavitation treatment section is pulverized by a swirling flow. [Figure 13] A diagram illustrating how gas from a gas introduction passage communicating with the outlet-side tapered section is pulverized by a swirling flow. [Figure 14]FIG. 1 is a first diagram showing a specific example of the shape of the tip of the gas introduction passage; [Figure 15] FIG. 2 is a second diagram showing a specific example of the tip shape of the gas introduction passage. [Figure 16A] FIG. 1 is a cross-sectional view showing details of the structure of the gas inlet side of the casing gas flow path. [Figure 16B] Illustrative diagram of the backflow prevention elastic ring during inhalation [Figure 16C] Illustration of the backflow prevention elastic ring's action when preventing backflow of liquid [Figure 17] Cross-sectional view showing an example of the configuration of a tap water treatment device that does not have a gas relay space [Figure 18] FIG. 10 is a front cross-sectional view showing a first modified example of the gas introduction passage; [Figure 19] FIG. 10 is a front cross-sectional view showing a second modified example of the gas introduction passage; [Figure 20] FIG. 10 is a front cross-sectional view showing a third modified example of the gas introduction passage; [Figure 21] FIG. 10 is a front cross-sectional view showing a fourth modified example of the gas introduction passage; [Figure 22] FIG. 10 is a front cross-sectional view showing a fifth modified example of the gas introduction passage; [Figure 23] FIG. 10 is a front cross-sectional view showing a sixth modified example of the gas introduction passage; [Figure 24] FIG. 1 is a schematic plan view showing a first example in which a plurality of gas introduction passages are formed by dividing the gas introduction passages into the upstream side and the downstream side of the liquid flow passage; [Figure 25] FIG. 10 is a schematic plan view showing a second example in which a plurality of gas introduction passages are formed by dividing the gas introduction passages into the upstream side and the downstream side of the liquid flow passage; [Figure 26] FIG. 10 is a schematic plan view showing a third example in which a plurality of gas introduction passages are formed by dividing the gas introduction passages into the upstream side and the downstream side of the liquid flow passage; [Figure 27] FIG. 10 is a schematic plan view showing a fourth example in which a plurality of gas introduction passages are formed by dividing the gas introduction passages into the upstream side and the downstream side of the liquid flow passage; [Figure 28A] FIG. 10 is a diagram showing a first modified example of the cross-sectional outer shape of the spiral groove. [Figure 28B] FIG. 10 is a diagram showing a second modified example of the cross-sectional outer shape of the spiral groove. [Figure 28C] FIG. 10 is a diagram showing a third modified example of the cross-sectional outer shape of the spiral groove. [Figure 29] A cross-sectional view showing an example of a water-passing attachment for a washing machine incorporating the liquid treatment nozzle of the present invention. [Figure 30] 30 is a schematic diagram showing an embodiment in which the water passage attachment of FIG. 29 is incorporated into the water supply path of a washing machine. [Figure 31] FIG. 1 is a side cross-sectional view showing an example of a shower head incorporating the liquid processing nozzle of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a front view and a bottom view of an example of a tap water treatment device incorporating a liquid treatment nozzle of the present invention. The tap water treatment device 100 includes a cylindrical main casing 40 made of metal or resin and having a water outlet 61, and a cylindrical outlet cap 60 removably attached to the bottom end of the main casing 40. A mesh member 63 for dispersing water flow is fitted into the tip opening of the outlet cap 60, covering the water outlet 61. As shown in FIG. 2, the tap water treatment device 100 is attached to the end of a water faucet unit 91 attached to a kitchen sink 93 (or washbasin, etc.) on the top end face of the main casing 40, which forms the water inlet. Tap water containing dissolved air supplied from the water faucet unit 91 is subjected to cavitation treatment as it passes through the tap water treatment device 100, becoming treated water DXW containing fine bubbles generated by the precipitation of dissolved air, which then flows out of the water outlet 61.

[0013] Figure 3 shows a plan view and a front cross-sectional view of the tap water treatment device 100 of Figure 1. A joint counterbore 41 opening to the upper end surface, a nozzle accommodating hole 44 communicating with the downstream side of the joint counterbore 41, and a main body outlet hole 45 communicating with the downstream side of the nozzle accommodating hole 44 are integrally formed coaxially through the main body casing 40. An internally threaded joint 42 is formed on the inner peripheral surface of the joint counterbore 41 to threadably mate with a male threaded fitting (not shown: for example, an M22 / pitch 1.25 male threaded aerator fitting) formed on the water faucet unit 91 side of Figure 2, and a seal ring 43 is attached to the bottom periphery of the joint 41 to provide a watertight seal between the joint and the water faucet unit.

[0014] Meanwhile, the lower end side of the main casing 40 forms a cylindrical outlet sleeve 64 whose diameter is reduced by a stepped surface 40a. The outlet cap 60 is attached to the main casing 40 by threading a female thread portion 60b formed on the inner peripheral surface into a male thread portion 64b formed on the outer peripheral surface of the outlet sleeve 64. A seal ring 33 is fitted at the base end position of the male thread portion 64b of the outlet sleeve 64 to seal between the outer peripheral surface of the outlet sleeve 64 and the inner peripheral surface of the outlet cap 60.

[0015] In addition, the peripheral edge of the tip opening of the outlet cap 60 forms a support flange 62 that projects radially inward, and the outer peripheral edge of the mesh member 63 is held in a state in which it is sandwiched in the axial direction between the lower end surface of the outlet sleeve 64 and the support flange 62 of the outlet cap 60. The inner space of the outlet sleeve 64 forms a water retention space 64a that is larger in diameter than the liquid outlet 4 of the liquid processing nozzle 1, and the thin water stream flowing out from the liquid outlet 4 spreads radially outward relative to the axis O within the water retention space 64a, and is rectified by the mesh member 63 at the water outlet 61, so that it flows out as a thicker water stream.

[0016] The mesh member 63 can be configured as, for example, a woven metal wire, and the mesh size is, for example, #150 to #635 (mesh size 0.020 mm to 0.109 mm, opening rate 25.0% to 41.7%), more preferably #200 to #500 (mesh size 0.026 mm to 0.077 mm, opening rate 25.8% to 36.8%). The mesh member 63 may be configured with only one sheet, or multiple sheets (for example, 2, 3, 4, or 5 sheets) may be stacked and arranged.

[0017] Next, the liquid processing nozzle 1 is fitted into the nozzle accommodating hole 44 of the main body casing 40. The nozzle accommodating hole 44 is formed into a cylindrical surface, and the peripheral edge of the main body side outlet hole 45 forms a support flange 44a that protrudes radially inward, and the liquid processing nozzle 1 is held in place with the outer peripheral edge of its lower end face abutting against the support flange 44a.

[0018] The liquid processing nozzle 1 includes a nozzle body 10 made of resin or metal. The nozzle body 10 has a through-shaped liquid flow path 2 formed therein, with a liquid inlet 3 opening at one end face (upper end face) and a liquid outlet 4 opening at the other end face (lower end face). In this embodiment, the nozzle body 10 is cylindrical, and the liquid flow path 2 is formed to penetrate the nozzle body 10 in the direction of its axis O (central axis).

[0019] 4 shows a plan view and a front cross-sectional view of the liquid treatment nozzle 1. In the liquid flow path 2, a spiral groove 50 is engraved in a section forming the middle of the inner peripheral surface in the direction of the axis O, the spiral groove having one or more turns, with the axis O as the spiral centerline. In the liquid treatment nozzle 1 of the present invention, this spiral groove 50 forms the cavitation treatment section 5. It is preferable that the spiral groove 50 is formed in the cavitation treatment section 5 for two or more turns, and in this embodiment, four turns are formed.

[0020] 5, on the inner peripheral surface of the cavitation treatment section 5, when the region that partitions adjacent circumferential portions in the direction of the axis O of the spiral groove 50 is defined as the inter-groove region 52 and the minimum inner diameter of the inter-groove region 21 is defined as the inter-groove region inner diameter D1, the engraving pitch P of the spiral groove 50 in the direction of the axis O is set to be larger than the inter-groove region inner diameter D1. In addition, the depth d of the spiral groove 50 is set to a value smaller than the engraving pitch P, and in this embodiment, a value of 10% to 40% (preferably 15% to 25%) of the inter-groove region inner diameter D1.

[0021] In addition, in a cross section including the axis O, the inter-groove region 52 has a flat (cylindrical) outer contour, and the spiral groove 50 is formed to bulge outward relative to the inter-groove region 52. Furthermore, the width W1 of the inter-groove region 52 in the direction of the axis O is set to be larger than the width W2 of the spiral groove 50 (see FIG. 6). As a result of the fact that adjacent winding portions of the spiral groove 50 in the direction of the axis O are partitioned by the flat inter-groove region 52, the overall shape of the spiral groove 50 is helical.

[0022] In a cross section including the axis O, the spiral groove 50 is formed to have an outer shape in which the groove depth continuously decreases from the position of the groove bottom 51 toward the adjacent inter-groove region 52 in the direction of the axis O. For example, as shown enlarged in Figure 6, the cross section of the spiral groove 50 is V-shaped, and the depth d of the spiral groove 50 can be set to a value not less than 80% and not more than 120% of the width W2 of the spiral groove 50.

[0023] Furthermore, when the section length of the cavitation treatment section 5 is L and the inner diameter of the inter-groove region is D1, L / D1 is set to a value of, for example, 1 to 10 (preferably 1 to 7). Furthermore, as shown in Figures 8 and 9, on a plane including the axis O, the angle λ1 formed between the groove bottom 51 and a reference plane α having the axis O as its normal line is, for example, 3° to 80°, and preferably 45° to 70°.

[0024] Next, downstream of the cavitation treatment section 5, an outlet-side tapered section 22, whose inner diameter gradually increases from the outlet of the cavitation treatment section 5 toward the liquid outlet 4, is formed so that its section length J is larger than the engraving pitch P of the spiral grooves 50. The opening area of ​​the liquid outlet 4 formed in the outlet-side tapered section 22 is adjusted to be 1.2 to 2 times (preferably 1.3 to 1.7 times: 1.5 times in this embodiment) the axial cross-sectional area of ​​the inter-groove region 52 of the cavitation treatment section 5 at the minimum inner diameter position. The formation section length J of the outlet-side tapered section 22 is, for example, 3 to 5 times the inner diameter D1 of the inter-groove region of the spiral groove 50, and the taper angle θ2 of the outlet-side tapered section 22 in a cross section including the axis O is, for example, 4° to 8°.

[0025] Meanwhile, in the liquid flow path 2, an inlet-side tapered section 21 is formed upstream of the cavitation treatment section 5, whose inner diameter gradually decreases from the liquid inlet 3 toward the inlet of the cavitation treatment section 5 at a gradient greater than that of the outlet-side tapered section 22. The liquid inlet 3 of the inlet-side tapered section 21 is formed to have a larger diameter than the liquid outlet 4 of the outlet-side tapered section 22. The opening area of ​​the liquid inlet 3 formed in the inlet-side tapered section 21 is adjusted to 2.5 to 8 times (preferably 3 to 7 times: 5 times in this embodiment) the axial cross-sectional area of ​​the inter-groove region 52 of the cavitation treatment section 5 at the minimum inner diameter position. The formation section length K of the inlet-side tapered section 21 is, for example, 1.5 to 3 times the inter-groove region inner diameter D1 of the spiral groove 50, and the taper angle θ1 of the inlet-side tapered section 21 in a cross section including the axis O is, for example, 15° to 40°.

[0026] The nozzle body 10 having the liquid flow path 2 including the cavitation treatment section 5 as described above can be formed by known processing methods such as cutting, injection molding, etc. Furthermore, when the nozzle body 10 is made of metal, it may be formed by casting using a method such as the lost wax method.

[0027] 4, the nozzle body 10 is formed with a gas introduction passage 20, one end of which opens on the outer surface of the nozzle body 10 and the other end of which communicates with the spiral groove 50 of the cavitation treatment unit 5. In this embodiment, the gas introduction passage 20 has a gas inlet 20E, which forms one end, opening on the outer peripheral surface of the nozzle body 10, and a gas outlet 20T, which forms the other end, opening into the spiral groove 50. The gas introduction passage 20 is provided such that an axis Q extending from the gas inlet 20E to the gas outlet 20T is inclined relative to an axis O of the liquid flow path 2 so that the gas inlet 20E is located closer to the liquid inlet 3 of the liquid flow path 2 than the gas outlet 20T. The angle λ2 formed between the axis Q and the axis O is preferably, for example, between 30° and 70°, and is set to 45° in this embodiment.

[0028] In this embodiment, the gas introduction passage 20 is formed so that the gas outlet 20T has a smaller diameter than the gas inlet 20E. Specifically, as shown in Fig. 14, the opening end of the gas outlet 20T (hereinafter referred to as the "tip") of the gas introduction passage 20 has a structure in which the diameter thereof is continuously reduced by a tapered reduced diameter portion 20B toward the gas outlet 20T.

[0029] In Fig. 4, the gas introduction passage 20 has an inner diameter δ2 of, for example, 0.8 mm to 1.3 mm (1.0 mm in Fig. 4) at the base end side portion 20P where the gas inlet 20E is located. The portion following this is a main body portion 20A whose inner diameter is reduced via a stepped surface. As shown in Fig. 14, the inner diameter δ1 of the main body portion 20A is, for example, 0.2 mm to 0.7 mm (preferably 0.3 mm to 0.6 mm; 0.5 mm in this embodiment), and the length of the section where the reduced diameter portion 20B is formed is adjusted to be 1.5 to 3 times the inner diameter of the main body portion 20A.

[0030] The diameter of the tip surface of the reduced diameter section 20B is determined so that the edge of the tip surface does not interfere with the inner peripheral surface of the spiral groove 50. A pinhole section 20S with a uniform inner diameter in the axial direction is formed in the portion extending from the tip surface to the inner surface of the spiral groove 50 toward the gas outlet 20T, and the gas outlet 20T is formed at the tip of the pinhole section 20S. The inner diameter TD of the pinhole section 20S (gas outlet 20T) is 0.05 mm to 0.2 mm (preferably 0.08 mm to 0.15 mm; in this embodiment, 0.1 mm) and is set smaller than the inner diameter δ1 of the main body section 20A. As shown in FIG. 15, the reduced diameter section 20B' of the gas introducing passage 20 can also be formed with a stepped surface in which the inner diameter is gradually reduced.

[0031] 4, the gas introduction passages 20 are provided at a plurality of locations at different positions in the direction of the axis O. Specifically, the gas introduction passages 20 include one that opens into an upstream half section in the direction of the axis O of the cavitation treatment section 5 (for distinction, (U) is added to the reference symbol "20") and one that opens into a downstream half section in the direction of the axis O (for distinction, (D) is added to the reference symbol "20"). Both gas introduction passages 20 (U, D) open into a gas outlet 20T at the bottom of the spiral groove 50.

[0032] 3, a casing gas flow path 46 is formed in the main casing 40, with a gas outlet 46T opening at one end which communicates with the gas inlet 20E of the gas introduction passage 20(U, D), and a gas inlet 46E opening on the outer peripheral surface of the main casing 40 opening at the other end, penetrating the wall portion which forms the nozzle accommodating hole 44. In addition, a gas relay space 7 is formed between the outer peripheral surface of the nozzle main body 10 and the inner peripheral surface of the nozzle accommodating hole 44, with the gas inlet 20E side of the gas introduction passage 20 and the gas outlet 46T side of the casing gas flow path 46 respectively communicating with each other.

[0033] 3, the gap formed between the bottom surface of an annular space-forming recess 26 formed in the circumferential direction at a midpoint in the direction of the axis O of the outer peripheral surface of the nozzle body 10 and the inner peripheral surface of the nozzle accommodating hole 44 forms the gas relay space 7. Circumferential grooves 31, 32 are formed at both ends of the nozzle body 10 in the direction of the axis O, and seal rings 24, 25 fitted into the grooves 31, 32 liquid-tightly seal the gap between the outer peripheral surface of the nozzle body 10 and the inner peripheral surface of the nozzle accommodating hole 44 (and thus the gas relay space 7) on both sides in the direction of the axis O. Both ends of the nozzle body 10 are clearance-fit with the inner peripheral surface of the nozzle accommodating hole 44, and the depth of the space-forming recess 26 (the radial width of the gas relay space 7 in the direction of the axis O) is set larger than the clearance of the clearance fit.

[0034] Next, an annular groove 47 is formed in the outer peripheral surface of the main casing 40 along the circumferential direction, and a gas inlet 46E of the casing gas flow path 46 opens at the bottom surface of the groove 47. Also, a backflow prevention elastic ring 70 is fitted into the groove 47, which allows gas to flow from the gas inlet 46E into the casing gas flow path 46, but prevents backflow liquid in the casing gas flow path 46 from flowing out through the gas inlet 46E.

[0035] As shown in the left side of Figure 16A, the elastic backflow prevention ring 70 is made of rubber and has a circular cross-section. The cross-section of the groove 47 is square, and the elastic backflow prevention ring 70 is fitted into both inner surfaces of the groove 47 in the axial direction of the main casing 40 (the vertical direction in the drawing) so that both sides of its outer periphery are loosely fitted. As shown in the right side of Figure 16A, the inner periphery of the elastic backflow prevention ring 70 forms a strip-shaped sealing surface 70c at the center of the width of the bottom surface of the groove 47, and crosses the gas inlet 46E to semi-seal it. As shown in the left side of Figure 16A, a gas guide gap 47A is formed between the inner periphery of the elastic backflow prevention ring 70 and the gas inlet 46E.

[0036] The operation of the liquid treatment nozzle 1 and the tap water treatment device 100 using it will be described below. As shown in Figure 2, when the tap water treatment device 100 is attached to a water faucet unit 91 and the water passage valve 91B is opened, tap water with dissolved air as a gas flows into the tap water treatment device 100 and flows out as treated water DXW. In Figure 3, the tap water flows from the liquid inlet 3 into the liquid flow path 2 of the liquid treatment nozzle 1 inside the main body casing 40, and is subjected to cavitation treatment by passing through the cavitation treatment device 5, becoming treated water containing fine bubbles. The treated water flows from the liquid outlet 4 into the water retention space 64a and then flows out from the water outlet 61 through the mesh member 63.

[0037] The tap water (liquid) supplied to the liquid flow path 2 is throttled and accelerated by the inlet-side tapered section 21. As shown in FIG. 7, part of this flow forms a central flow MF and flows near the center of the cross section of the liquid flow path 2, while the remaining flow is distributed to the spiral groove 50 of the cavitation treatment unit 5, forming a swirling flow CF. As shown in FIG. 8, the distributed flow that collides with the inner circumferential surface of the spiral groove 50 swirls while being guided by the spiral groove 50, and its speed is increased by the centrifugal force. As shown in FIG. 7, the internal space of the spiral groove 50 is enhanced by the formation of a swirling flow CF due to the swirling effect of this centrifugal force. The region of the accelerated swirling flow CF becomes a negative pressure region according to Bernoulli's theorem, and the cavitation effect causes the dissolved air concentration to become supersaturated, resulting in treated water in which a large amount of fine bubbles with a diameter of less than 1 μm (so-called ultrafine bubbles) are precipitated.

[0038] Microbubbles in treated water can be detected, for example, using a laser scattering particle size analyzer. Treated water is also thought to contain a large number of bubble precipitation nuclei that stop growing before becoming observable bubbles. These bubble precipitation nuclei are thought to be 10 nm or less in size, making them difficult to detect using conventional measuring devices. For example, Non-Patent Document 1 describes a case in which treated water in which microbubbles were formed by mixing gas and liquid using water hammering was frozen, and microbubbles of a size thought to correspond to the bubble precipitation nuclei were confirmed by observing them using a cryo-ultra-high voltage electron microscope.

[0039] The liquid treatment nozzle 1 of the present invention generates a swirling flow CF due to the spiral groove 50, significantly improving the cavitation effect and thus the efficiency of generating fine bubbles, compared to nozzles with linear throttle mechanisms such as the Venturi tubes of Patent Documents 1 to 6. Furthermore, a screw member for forming a cavitation point, as in Patent Documents 7 and 8, is not required. Furthermore, flow loss due to wall friction is usually large near the inner circumferential surface of the liquid flow path that forms the throttle portion of the Venturi tube. However, with the configuration of the liquid treatment nozzle 1 of Figure 4, the flow velocity near the inner circumferential surface of the cavitation treatment unit 5 is increased by the formation of a swirling flow CF, thereby keeping pressure loss low when the liquid treatment nozzle 1 is inserted into a flow path in the form of the above-mentioned tap water treatment device 100, etc.

[0040] In order to increase the flow velocity of the swirling flow CF generated in the spiral groove 50 in the liquid treatment nozzle 1 of the present invention and thereby enhance the cavitation effect and, in turn, the microbubble generation effect, it is desirable that the cavitation treatment unit 5 does not include any pressure loss elements other than the spiral groove 50. For example, it is desirable that the screw members protruding from the inner surface of the flow path, as in the liquid treatment nozzles disclosed in Patent Documents 7 and 8, be eliminated in the liquid treatment nozzle 1 of the present invention. Eliminating the need for screw members not only reduces the number of parts, but also means that no pressure loss occurs due to screw members protruding into the inner surface of the flow path. As a result, the flow rate and flow velocity of the liquid flowing through the cavitation treatment unit 5 are increased, resulting in the advantage of obtaining treated water containing a large amount of microbubbles while ensuring a sufficient flow rate even with, for example, a relatively low water supply pressure.

[0041] The inventors conducted an analysis using a fluid simulation system based on the finite element method (FEM). As shown in FIG. 7, the velocity of the swirling flow CF induced by the spiral groove 50 increases with the number of spiral turns from the starting point of the spiral groove 50 toward the downstream side, i.e., toward the downstream side. (In the figure, the wider the curve representing the swirling flow CF, the higher the flow velocity.) That is, upstream, where the number of spiral turns is relatively small, the flow is immediately constricted by the inlet-side tapered section 21, and the flow distribution along the spiral groove 50 is small, resulting in a central flow MF. However, downstream, where the number of spiral turns increases, the flow distribution along the spiral groove 50 accumulates integrally, resulting in the development of the swirling flow CF and a significant increase in the circumferential flow velocity. If the spiral groove 50 is formed for less than one turn, the development of the swirling flow CF is insufficient, resulting in insufficient cavitation and thus insufficient microbubble generation. As mentioned above, it is preferable for the spiral groove 50 to be formed for two or more turns.

[0042] 8 and 9, the flow F flowing in the axial direction along the inner surface of the cavitation treatment section 5 is decomposed into a straight component LF that attempts to overcome the inter-groove region 52 of the spiral groove 50, and a swirling flow CF component that flows along the spiral groove 50. It is thought that the swirling flow CF component increases each time it overcomes the inter-groove region 52, that is, each time it makes a turn around the spiral groove 50. In this case, it is thought that the distribution ratio of the swirling flow CF generated per turn increases as the angle λ1 formed between the axis O and the groove bottom 51 with respect to the plane including the axis O increases, that is, as the engraving pitch P of the spiral groove 50 increases.

[0043] In particular, as shown in Figure 8, by setting the pitch P of the spiral groove 50 in the axial direction O to be larger than the inner diameter D1 of the inter-groove region, a significant swirling flow CF can be generated even if the number of revolutions of the spiral groove 50 is relatively small, thereby making the cavitation effect and, in turn, the effect of generating fine bubbles remarkable. On the other hand, as shown in Figure 9, when the pitch P of the spiral groove 50 is smaller than the inner diameter D1 of the inter-groove region, the distribution ratio of the swirling flow CF generated per revolution is small. However, even in this case, by ensuring a larger number of revolutions of the spiral groove 50, it may be possible to achieve a sufficient cavitation effect.

[0044] 5, if the depth d of the spiral groove 50 is too large, the fluid resistance when the flow overcomes the inter-groove region 52 becomes excessive, which increases the pressure loss when the flow passes through the cavitation treatment section 5, leading to a decrease in flow velocity and making it impossible to obtain a sufficient cavitation effect. From this perspective, it is effective to set the depth d of the spiral groove 50 to be smaller than the engraving pitch P of the spiral groove.

[0045] On the other hand, if the depth d of the spiral groove 50 is too shallow, the fluid resistance when the flow overcomes the inter-groove region 52 decreases, and the induction effect of the swirling flow CF along the spiral groove 50 becomes insufficient, which may lead to insufficient cavitation effect. From this perspective, it is effective to set the depth of the spiral groove 50 to 10% or more of the inner diameter D1 of the inter-groove region.

[0046] 7, in a cross section including the axis O, the outer contour of the inter-groove region 52 may be flat (cylindrical: it may be a tapered surface with a smaller gradient than the outlet-side tapered portion 22) and the spiral groove 50 may be configured to bulge outward relative to the inter-groove region 52 (i.e., the entire spiral groove 50 may be formed in a helical shape), thereby increasing the effect of the central flow MF confining the swirling flow CF within the spiral groove 50. As a result, the swirling flow CF can be accelerated, contributing to an enhanced cavitation effect. Furthermore, by forming the inter-groove region 52 into a cylindrical surface, turbulence in the central flow MF flowing over the surface of the inter-groove region 52 is reduced, and the swirling flow CF can be more effectively confined within the spiral groove 50.

[0047] 6, in order to enhance the effect of containing the swirling flow CF within the spiral groove 50, it is desirable to set the width W1 of the inter-groove region 52 in the direction of the axis O to be larger than the width W2 of the spiral groove 50. Similarly, it is effective to set the depth d of the spiral groove 50 to a value between 10% and 40% (preferably between 15% and 25%) of the inner diameter D1 of the inter-groove region, and further to a value between 80% and 120% of the width W2 of the spiral groove 50.

[0048] To enhance the generation of swirling flow CF along the spiral groove 50, it is effective to form the spiral groove 50 so that its depth continuously decreases from the groove bottom 51 toward the adjacent inter-groove region 52 in the axial direction O. For example, as shown in the enlarged view of FIG. 6, it is effective to form the spiral groove 50 in a V-shaped cross section. In particular, adopting a V-shaped cross section in which the groove width decreases significantly toward the groove bottom is advantageous for locally increasing the flow velocity near the groove bottom and further enhancing the level of pressure reduction due to cavitation. Note that in FIG. 6, the spiral groove 50 has a V-shaped cross section with a slightly outwardly bulging inner surface. However, as shown in FIG. 28B, it may have a U-shaped cross section, or a sharp V-shape without any bulging, as shown in the left side of FIG. 28C. Furthermore, as shown in the right side of FIG. 28C, it is also possible to form a V-shaped spiral groove 50 with a flat groove bottom.

[0049] Furthermore, when the length of the passage section of the cavitation treatment section 5 is L and the inner diameter of the inter-groove region is D1, if the value of L / D1 is too large, the flow resistance when the liquid flow passes through the cavitation treatment section 5 becomes too large, and a significant cavitation effect may not be obtained. From this perspective, it is said to be effective to set the value of L / D1 to 10 or less.

[0050] FIG. 10 is an explanatory diagram showing the fine bubble generation and crushing effect of the spiral groove 50, with the gas introduction passage 20 omitted. The flow F supplied to the cavitation treatment unit 5 develops a swirling flow CF more significantly as it moves downstream of the spiral groove 50, and when the flow velocity reaches 5 m / s or more, bubble nuclei BN begin to be generated by the cavitation effect. It is believed that the amount of bubble nuclei BN generated increases downstream, where the flow velocity of the swirling flow CF increases. Furthermore, the area where bubble nuclei BN are particularly likely to be generated is near the groove bottom 51 of the spiral groove 50, where the flow velocity is more likely to increase.

[0051] If the reduced pressure continues, the generated bubble nuclei BN will grow by absorbing supersaturated gas components in the liquid. However, inside the spiral groove 50, where the swirling flow CF is significantly formed, new bubble nuclei BN are continuously generated due to the cavitation effect. Due to the strong negative pressure, these nuclei rapidly grow into bubbles. The liquid in the cavitation treatment unit 5 enters a turbulent agitation state similar to bumping. The grown bubbles are also caught in the turbulence, and at least some of them are finely pulverized into ultrafine bubbles. In liquid treatment nozzles using threaded members such as those described in Patent Documents 7 and 8, the cavitation point is limited to the vicinity of the thread root of the threaded member, and the bumping region associated with bubble deposition is limited to the region directly below the threaded member. Therefore, the re-pulverization effect of grown bubbles is somewhat inferior. In contrast, the configuration of the liquid processing nozzle 1 of the present invention ensures the cavitation effect and therefore the turbulent stirring effect due to bubble precipitation throughout the entire formation section of the spiral groove 50, resulting in an excellent re-crushing effect of grown bubbles, and for example, the number and density of ultra-fine bubbles generated can be significantly increased.

[0052] Furthermore, if the outlet-side tapered section 22 is formed downstream of the cavitation treatment section 5 so that its section length is longer than the engraving pitch P of the spiral grooves 50, the swirling flow CF generated in the cavitation treatment section 5 can be brought as a continuous swirling flow SF into the outlet-side tapered section 22, which does not have spiral grooves 50. As a result, bubbles that have been generated and grown in the cavitation treatment section 5 or bubbles introduced from the gas introduction passage 20 can be pulverized by the continuous swirling flow SF even in the outlet-side tapered section 22, contributing to an increase in the number and density of fine bubbles or ultra-fine bubbles generated.

[0053] The continuous swirling flow SF is more easily formed as the pressure loss due to the expansion of the flow in the outlet-side tapered section 22 decreases. From this perspective, it is effective to adjust the opening area of ​​the liquid outlet 4 to 1.2 to 2 times (preferably 1.3 to 1.7 times: 1.5 times in this embodiment) the axial cross-sectional area of ​​the inter-groove region 52 of the cavitation treatment section 5 at the minimum inner diameter position, and to set the formation section length of the outlet-side tapered section 22 to, for example, 3 to 5 times the inter-groove region inner diameter D1 of the spiral groove 50.

[0054] Next, the function and effect of the gas introduction passage 20 and its surrounding structure will be described. In the configuration of the liquid processing nozzle 1 shown in Figure 5, the gas introduction passage 20 (U, D) has a gas outlet 20T opening into the spiral groove 50 that forms the cavitation treatment section 5. As already explained, a strong swirling flow CF is generated within the spiral groove 50, and it is considered that the negative pressure acting on the swirling flow CF is higher than that acting on a normal venturi constriction that does not form a spiral groove 50. Therefore, a suction force higher than that of a normal venturi tube is generated in the gas introduction passage 20 (U, D), making it possible to self-suck gas (outside air in this embodiment) from the gas inlet 20E, and by entraining and pulverizing the gas in the swirling flow CF generated within the spiral groove 50, the amount of fine bubbles generated can be further increased.

[0055] In the configuration of the liquid processing nozzle 1 in Fig. 4, the gas introduction passage 20(U) is open to the cavitation treatment section 5 (spiral groove 50) in the upstream half section in the direction of the axis O. As shown in Fig. 11, the coarse bubbles LB sucked in at this position are vigorously crushed over a long section in the downstream spiral groove 50 by the strong swirling flow CF and the stirring turbulence caused by bubble deposition, which contributes greatly to an increase in the number and density of ultra-fine bubbles generated.

[0056] In the upstream half of the spiral groove 50, the swirling flow CF is still in the developing stage and its flow velocity is relatively low, so the negative pressure level associated with the swirling flow CF is also somewhat low. As a result, the amount of gas drawn in is thought to be somewhat smaller. If excessive gas is mixed into the flow upstream of the spiral groove 50, the groove bottom 51 of the spiral groove 50 will frequently come into direct contact with coarse bubbles downstream. Even if the flow velocity of the swirling flow CF is high, the groove bottom 51 in contact with coarse bubbles does not contribute to new bubble nucleation by cavitation. This impairs the efficiency of fine bubble generation and the efficiency of bubble crushing by turbulent mixing, resulting in a decrease in the number and density of ultrafine bubbles. Therefore, preventing an excessive increase in the amount of gas drawn in through the gas introduction passage 20(U) in the upstream half of the spiral groove 50 contributes to reducing the occurrence of the above-mentioned problems and is advantageous for increasing the number and density of ultrafine bubbles.

[0057] On the other hand, in the configuration of the liquid processing nozzle 1 in Figure 4, the gas introduction passage 20(D) is open to the downstream half section in the axial direction of the cavitation treatment section 5 (spiral groove 50). As shown in Figure 12, in the downstream half section of the spiral groove 50, the swirling flow CF is sufficiently developed and the flow velocity is high, so the level of negative pressure generated by the swirling flow CF is also high. Therefore, in the gas introduction passage 20(D), the amount of coarse bubbles LB sucked in by the accelerated swirling flow CF is large, but the length of the section subjected to pulverization by the swirling flow CF and the stirring turbulence associated with bubble deposition is short. Therefore, the coarse bubbles LB are advantageous in increasing the number and density of fine bubbles FB generated that are 1 µm or larger.

[0058] Ultrafine bubbles and even smaller bubble nuclei are said to improve the macroscopic permeability of water. In contrast, fine bubbles in the fine bubble range of 1 μm or larger are said to have significant effects, such as dirt removal, due to the adsorption action caused by the charge on the bubble surface and the impact force associated with the contraction and collapse of ion-adsorbed bubbles. It has been found that, whether using the gas introduction passage 20(U) or the gas introduction passage 20(D), when tap water is treated while air is being sucked through the liquid treatment nozzle 1 of the present invention, a large amount of fine bubbles in the bubble diameter range of 1 μm to 20 μm (particularly 1 μm to 5 μm) are likely to be produced. Treated water with an increased production of fine bubbles in this range not only exhibits particularly significant dirt removal effects, but also has the advantage of being easily visually recognized because the water remains significantly cloudy for a long period of time due to light scattering by the fine bubbles.

[0059] 13, the gas introduction passage 20(D) can also be provided so as to communicate with the outlet side tapered portion 22. If the configuration is provided with the outlet side tapered portion 22, even if it is difficult for a normal Venturi tube to suck gas from the outlet side tapered portion 22, it is possible to self-suck gas by using the continuous swirling flow SF generated in the outlet side tapered portion 22.

[0060] In both the gas introduction passage 20(U) and the gas introduction passage 20(D), the gas outlet 20T of the gas introduction passage 20 is connected to the bottom of the spiral groove 50, where the flow velocity of the swirling flow CF is increased, thereby improving the self-priming efficiency of the gas. Furthermore, by forming the reduced-diameter section 20B, the gas outlet 20T is formed to have a smaller diameter than the gas inlet 20E, thereby reducing the diameter of the coarse bubbles supplied from the gas outlet 20T into the flow F and improving the efficiency of crushing them into fine bubbles. In particular, to improve the generation efficiency of ultrafine bubbles and fine bubbles of 1 to 5 μm, it is effective to form the gas outlet 20T with a pinhole section 20S having an inner diameter TD of 0.05 mm to 0.2 mm (preferably 0.08 mm to 0.15 mm; in this embodiment, 0.1 mm), as shown in FIGS. 14 and 15 .

[0061] If the flow load on the liquid outlet 4 side of the liquid processing nozzle 1 increases for some reason, the liquid in the cavitation treatment device 5 will be subjected to back pressure resulting from the flow load. If this back pressure becomes higher than the gas inflow pressure into the gas introduction passage 20 due to the negative pressure resulting from the swirling flow CF, the liquid will flow back from the cavitation treatment device 5 side to the gas introduction passage 20, and may flow out to the gas inlet 20E side.

[0062] The gas introducing passage 20 may be formed so that the axis Q from the gas inlet 20E to the gas outlet 20T is perpendicular to the axis O of the liquid flow path 2, for example. However, by providing the gas inlet 20E at an angle so that it is located closer to the liquid inlet 3 of the liquid flow path 2 than the gas outlet 20T, it is possible to effectively suppress backflow of liquid into the gas introducing passage 20 as described above. Furthermore, as shown in FIG. 14, a tapered structure in which the diameter of the reduced diameter section 20B is continuously reduced is more effective in reducing pressure loss in the self-priming gas due to the reduction in the cross-sectional area of ​​the flow path than a structure in which the diameter of the reduced diameter section 20B' is formed with a stepped surface as shown in FIG. 15. For example, by forming the reduced diameter section 20B in a tapered structure with reduced pressure loss, as in the configuration shown in FIG. 14, it is possible to further reduce the occurrence of backflow of liquid toward the gas inlet 20E.

[0063] In the configuration of the tap water treatment device 100 in Figure 3, a casing gas flow path 46 is formed by penetrating the wall portion that forms the nozzle accommodating hole 44 of the main casing 40, and the negative suction pressure that occurs in the multiple gas introduction paths 20 (U, D) of the liquid treatment nozzle 1 as the liquid flows is transmitted to the casing gas flow path 46 via the gas relay space 7. This makes it possible to reduce the number of casing gas flow paths 46 formed in the main casing 40, contributing to simplifying the structure of the main casing 40. It is also possible to reduce the number of areas where liquid leakage due to liquid backflow is a concern.

[0064] Furthermore, an annular groove 47 is formed on the outer peripheral surface of the main casing 40, and a gas inlet 46E of the casing gas flow path 46, which opens into the bottom surface of the groove 47, is semi-sealed by an elastic backflow prevention ring 70 fitted into the groove 47. Even if backflow liquid enters the casing gas flow path 46, the elastic backflow prevention ring 70 effectively prevents the liquid from leaking out from the gas inlet 46E.

[0065] 16A left, the elastic backflow prevention ring 70 is made of rubber (a so-called O-ring) and has a circular cross section, and is loosely fitted into the groove 47 having a square cross section, with a gas guide gap 47A being formed between the inner peripheral surface of the elastic backflow prevention ring 70 and the gas inlet 46E. With this configuration, the only flow resistance when gas flows from the gas inlet 46E into the casing gas flow path 46 is the linear loose-fitting space between the elastic backflow prevention ring 70 and both inner surfaces of the groove 47. Therefore, even though the gas inlet 46E is semi-sealed by the elastic backflow prevention ring 70, the gas can flow smoothly into the casing gas flow path 46.

[0066] 16B illustrates the function of the elastic backflow prevention ring 70 during intake. When negative pressure NP is induced in the casing gas flow path 46 as liquid flows through the liquid processing nozzle, the intake airflow pulls the elastic backflow prevention ring 70 into the casing gas flow path 46 at the gas inlet 46E. As a result, the portion of the elastic backflow prevention ring 70 facing the gas inlet 46E is crushed and deformed in a manner that reduces the cross-sectional diameter in the width direction of the groove 47, and a gap GP is created between the inner surface of the groove 47 and the elastic backflow prevention ring 70. A gas flow AF is sucked from this gap into the casing gas flow path 46 through the gas guiding gap 47A.

[0067] On the other hand, Figure 16C illustrates the function of the backflow prevention elastic ring 70 when liquid flows back from the liquid processing nozzle toward the casing gas flow path 46. As shown in the left side of Figure 16C, the liquid flow WF attempting to flow back is more viscous and has a greater surface tension than the gas flow. Therefore, the resistance to passing through the minute gap (or loosely fitted surface) between the groove 47 and the backflow prevention elastic ring 70 is much greater than that of the gas flow. Therefore, as shown in the right side of Figure 16C, the liquid flow WF is pressurized by the positive pressure PP due to the backflow from the casing gas flow path 46, while its outflow through the gap GP is obstructed. This pressurization causes the portion of the backflow prevention elastic ring 70 facing the gas inlet 46E to collapse and deform in a direction that increases the cross-sectional diameter in the width direction of the groove 47. However, this deformation is restricted by the inner surface of the groove 47, which increases the contact area between the backflow prevention elastic ring 70 and the inner surface of the groove 47, thereby more firmly blocking the liquid flow WF.

[0068] Various modified embodiments of the present invention will be described below. In the tap water treatment device 100' shown in Figure 17, no space-forming recess is formed in the liquid treatment nozzle 1, and the entire outer peripheral surface of the liquid treatment nozzle 1 is loosely fitted against the inner peripheral surface of the nozzle accommodating hole 44 (i.e., a configuration in which the gas relay space is omitted). The main casing 40 is individually formed with casing gas flow paths 46 corresponding to the multiple gas introduction passages 20 formed in the liquid treatment nozzle 1. The multiple gas introduction passages 20 are formed by dividing them into the first half section and the second half section of the cavitation treatment unit 5, and a set of a groove portion 47(U) and a backflow prevention elastic ring 70(U) that covers the gas introduction passage 20(U) in the first half section, and a set of a groove portion 47(D) and a backflow prevention elastic ring 70(D) that covers the gas introduction passage 20(D) in the steel plate section are individually provided.

[0069] The gas introduction passage 20 formed in the liquid processing nozzle 1 may be provided only in the front half of the cavitation treatment section 5 as shown in FIG. 18, or only in the rear half of the cavitation treatment section 5 as shown in FIG. 19. Furthermore, as shown in FIGS. 20 to 23, multiple gas introduction passages 20 may be distributed and formed at different positions on the spiral groove 50 in the axial direction of the cavitation treatment section 5. The configuration of FIG. 20 illustrates an example in which two gas introduction passages 20 are formed in the spiral groove 50 so as to communicate with the groove bottom of the first turn from the liquid inlet 3 side and the groove bottom of the second turn, respectively. The configuration of FIG. 21 illustrates an example in which a third gas introduction passage 20 communicating with the groove bottom of the third turn from the liquid inlet 3 side is added to the configuration of FIG. 20. The configuration of FIG. 22 illustrates an example in which a fourth gas introduction passage 20 communicating with the groove bottom of the fourth turn from the liquid inlet 3 side is added to the configuration of FIG. 21. 23 shows an example in which two gas introduction passages 20 communicating with the outlet-side tapered portion 22 are added to the configuration of FIG.

[0070] Furthermore, as shown in Figs. 24 to 27, a plurality of gas introduction passages 20 can be formed in various numbers in the first half section (upstream side) and the second half section (or outlet-side tapered section 22: downstream side) of the cavitation treatment section 5. Fig. 24 shows an example in which one gas introduction passage 20 is formed on the upstream side and two gas introduction passages 20 are formed on the downstream side with an angular phase shift of 180°. Fig. 25 shows an example in which one gas introduction passage 20 is formed on the upstream side and three gas introduction passages 20 are formed on the downstream side with an angular phase shift of 120°. Fig. 26 shows an example in which three gas introduction passages 20 are formed on the upstream side with an angular phase shift of 120° and six gas introduction passages 20 are formed on the downstream side with an angular phase shift of 60°. FIG. 27 shows an example in which two gas introduction passages 20 are formed on the upstream side with an angular phase difference of 180°, and two gas introduction passages 20 are formed on the downstream side with an angular phase difference of 180°.

[0071] FIG. 28A shows a cavitation nozzle 1" having a spiral groove 50" according to a modified embodiment. In this embodiment, the width of the spiral groove 50" is expanded in the direction of the axis O, and the corresponding edges in the width direction are connected to form a thin ridge-like inter-groove region 52. The thick solid line (the portion located on the near side in the direction perpendicular to the paper surface) and the thick broken line (the portion located on the far side in the direction perpendicular to the paper surface) in the figure indicate the groove bottom (valley bottom) 51, and the thick dashed line (the portion located on the near side in the direction perpendicular to the paper surface) and the thin dashed line (the portion located on the far side in the direction perpendicular to the paper surface) in the figure indicate the ridge-like inter-groove region 52. Accordingly, the outer shape of the spiral groove 50 has a triangular wave shape (in this case, the inner diameter D1 of the inter-groove region is the inner diameter at the ridge position of the inter-groove region 52). The outer shape of the spiral groove 50 may be a sinusoidal wave shape or a wave shape formed by alternatingly connecting semi-elliptical curves that are inversely related to each other. A spiral groove 50" having such a shape reduces the resistance of the entire inner surface of the cavitation treatment section 5, including the inter-groove region 52, although the containment effect of the swirling flow is somewhat impaired. This makes it possible to ensure a relatively good cavitation effect and therefore a relatively good effect of generating fine bubbles.

[0072] FIG. 29 is a cross-sectional view showing an example of a water treatment attachment for a washing machine incorporating a liquid treatment nozzle of the present invention. The water treatment attachment 300 includes a main casing 340. The main casing 340 has a joint counterbore 341 opening at its upper end, a nozzle receiving hole 344 communicating with the downstream side of the joint counterbore 341, and a main body outlet hole 345 communicating with the downstream side of the nozzle receiving hole 344, all of which are integrally formed coaxially through the main casing 340. The inner peripheral surface of the joint counterbore 341 is formed with a female threaded joint 342 that threadably engages with a male threaded fitting (e.g., a G1 / 2 male thread) formed on the water faucet unit. Meanwhile, a hose connection part 349 is formed at the lower end of the main casing 340. In this embodiment, the hose connection part 349 is formed as a bamboo-like joint. The liquid processing nozzle 1 accommodated in the nozzle accommodating hole 344 has a configuration similar to that shown in Fig. 18, for example, and detailed description thereof will be omitted. Outside air is self-absorbed into the gas introduction passage 20 formed in the liquid processing nozzle 1 via the gas relay space 7 and the casing gas flow path 346 on the main casing 340 side. Also, reference numeral 370 denotes an elastic ring for preventing backflow, similar to that in Fig. 3.

[0073] 30 shows an example of how water treatment attachment 300 is used. Water treatment attachment 300 is used by connecting female threaded joint 342 to water faucet unit 91 for supplying wash water, which is installed in the washing machine area of ​​the home, and hose connection part 349 to water supply hose 92 attached to water supply inlet 401 of washing machine 400. Tap water with dissolved air supplied from water faucet unit 91 is subjected to cavitation treatment while self-absorbing outside air as it passes through water treatment attachment 300, becoming treated water containing fine bubbles. This treated water is supplied to the washing tub (not shown) of washing machine 400 via water supply hose 92. The treated water contains a large amount of ultra-fine bubbles due to the cavitation effect, and when this water is supplied to the washing tub, the washing effect for clothes and the like is greatly improved.

[0074] The liquid processing nozzle 1 may also be configured without a gas introduction passage. Figure 31 shows an example of a showerhead incorporating such a liquid processing nozzle 1'. The showerhead 201 has a hose connection portion 281t consisting of a male thread, and is used by connecting the hose connection portion 281t to a shower hose (not shown). The showerhead 201 includes a hollow main body 250 having a water inlet opening 281, a discharge opening 201L, and a water supply channel 221 connecting the water inlet opening 281 and the discharge opening 201L, and a shower sprinkler plate (hereinafter simply referred to as the "sprinkler plate") 203 attached to the discharge opening 201L of the main body 250. The water inlet opening 281 opens at the rear end surface of the hose connection portion 281t.

[0075] The main body 250 includes a head main portion 251 in which the discharge opening 201L is formed, a cylindrical handle portion 252, and a tail cap 208 detachably connected to the handle portion 252. The handle portion 252 has a first end connected to the head main portion 251 and has a handle flow path 221A formed therein that forms a part of the water supply passage 221. A handle-side coupling portion 226 is formed at a second end of the handle portion 252. The tail cap 208 has a cap flow path 208A formed therein that forms a part of the water supply passage 221, a water supply opening 281 opening at the first end, and is detachably and liquid-tightly connected to the handle-side coupling portion 226 at the second end. A liquid treatment nozzle 1' according to an embodiment of the present invention is incorporated into the cap flow path 208A of the tail cap 208 as a water treatment nozzle for cavitation treatment of shower water flow.

[0076] The additive eluting cartridge 206 can be inserted axially into the handle flow path 221A of the handle portion 252 from the handle-side connecting portion 226 side of the tail cap 208 (the additive eluting cartridge 206 is inserted into the handle flow path 221A with the tail cap 208 removed). The additive is, for example, a chlorine remover such as L-ascorbic acid, a carbon dioxide generator, or a fragrance. When the additive eluting cartridge 206 is placed in the handle flow path 221A, the gap between the inner circumferential surface of the handle flow path 221A and the outer circumferential surface of the additive eluting cartridge 206 functions as a water flow path.

[0077] 4 except that the shape of the nozzle body 10 has been modified to allow for incorporation into the shower head 201 and the gas introduction passage 20 has been omitted, and the same components are given the same reference numerals and detailed descriptions are omitted. The liquid treatment nozzle 1' is mounted axially within the tail cap 208 so that the liquid inlet 3 faces the water supply opening 281 and the liquid outlet 4 faces the handle flow path 221A.

[0078] In the shower head 201, the cavitation effect caused by the water passing through the liquid treatment nozzle 1' causes treated water containing a large amount of ultra-fine bubbles to be sprayed from the spray plate 203, improving the water's permeability and providing good moisturizing and cleansing effects on skin and hair. If the head main part 251 is removed from the tail cap 208 and water is passed through, pressure loss in the head main part 251 is eliminated, allowing the treated water that has passed through the water treatment nozzle 207 to be sprayed directly from the tail cap 208 at higher pressure (higher velocity). This is convenient for use in cleaning drains and other areas in the bathroom.

[0079] The results of various experiments conducted to confirm the effects of the liquid treatment nozzle of the present invention will be described below. (Experimental Example 1) Various prototypes of the liquid treatment nozzle 1 (with the gas introduction passage 20 omitted) with the external shape shown in Figure 4 were created with various changes to the formation form of the spiral groove 50, and were incorporated into the tap water treatment device 100 of Figure 3. The specific dimensional settings of each prototype are summarized in Table 1. Specifically, the dimensions of each part of the liquid treatment nozzle 1 were set as follows (see Figure 5). Length of spiral groove 50 L: 2.25~11mm Depth d of the spiral groove 50: 0 to 0.7 mm (0 mm is a comparative example in which no spiral groove is formed: number 11) Width of spiral groove 50 W2: 0.5 mm ·Groove area inner diameter D1: 2mm Number of spiral groove turns: 0 to 8 (0.5 is the comparative example: number 10, 0 is the comparative example without spiral grooves: number 11) Spiral groove 50 pitch P: 1.4~4.5mm Inner diameter D2 of liquid inlet 3: 4.5mm Inner diameter D3 of liquid outlet 4: 2.5mm Length of the inlet side tapered section 21: 5 mm Length of the outlet side tapered section 22: 7 mm Mesh material 63: 3-ply laminated mesh size #400 (mesh size 0.034 mm, opening rate 27.8%) Nozzle No. 9 was created based on the same dimensional conditions as nozzle No. 2, except that the width of the spiral groove 50 was 2.75 mm and its cross-sectional shape was the type shown in Figure 28A.

[0080] The tap water treatment device 100 described above was connected to a tap unit as shown in Figure 2, and the outlet water flow rate was adjusted to 4 L / min by manually operating the water flow valve 91B. The number formation density and number bubble size distribution of the resulting treated water were measured using a laser scattering nanoparticle size distribution measurement device (Shimadzu Corporation: SALD-7500nano). Note that the bubble size measurement of the treated water was performed 15 seconds after the water intake. The results are summarized in Table 1.

[0081] [Table 1]

[0082] The treated water passing through liquid treatment nozzles Nos. 1 to 8 according to the present invention, each having a spiral groove 50 cut into it at least one full turn, produces a much higher number of bubbles in the ultra-fine bubble range (less than 1 μm) than liquid treatment nozzle No. 11 (a typical Venturi tube) without a spiral groove 50 or liquid treatment nozzle No. 10, which has a groove length of less than one full turn. Furthermore, even though none of the nozzles draws in external air and relies solely on bubble precipitation through cavitation, they produce ultra-fine bubbles in the range of 0.3 μm or less in diameter at a high density of 22 million to 300 million bubbles / cc. Furthermore, nozzle No. 9, which has a spiral groove 50 in the form shown in Figure 28A, is slightly inferior in terms of dimensions to the corresponding nozzle No. 2, but still produces ultra-fine bubbles at a sufficient density.

[0083] When the spiral groove depth d is fixed at 0.5 mm, for example, the liquid treatment nozzles Nos. 2 to 4, in which the engraving pitch P of the spiral groove 50 is set larger than the inner diameter D1 of the inter-groove region, generate more bubbles in the ultra-fine bubble region with a diameter of 0.3 μm or less than the liquid treatment nozzle No. 1, in which the engraving pitch P is set smaller than the inner diameter D1 of the inter-groove region. In this case, the liquid treatment nozzle No. 2, in which the spiral groove 50 has a greater number of turns and an engraving pitch P of 2.75 mm, generates bubbles in the ultra-fine bubble region at a high density of more than 300 million bubbles / cc.

[0084] Furthermore, when the formation section length and engraving pitch P of the spiral groove 50 are fixed at, for example, 11 mm and 2.75 mm, respectively, it can be seen that the liquid treatment nozzles Nos. 2, 6, and 8, in which the depth d of the spiral groove 50 is set to a value exceeding 10% (0.2 mm) of the inner diameter D1 of the inter-groove region, generate bubbles in the ultra-fine bubble region at a higher density than the liquid treatment nozzle No. 5, in which the depth d of the spiral groove 50 is less than 10% of the inner diameter D1 of the inter-groove region.

[0085] (Experimental Example 2) Prototypes of the liquid treatment nozzle 1 with the external shape shown in Figure 4 were created by forming the gas introduction passage 20 in various layouts and incorporated into the tap water treatment device 100 of Figure 3. The dimensions of each part of the liquid treatment nozzle 1 were set as follows (see Figure 5). Length of spiral groove 50 L: 11 mm Depth d of spiral groove 50: 0.5 mm or 0.3 mm Width of spiral groove 50 W2: 0.5 mm ·Groove area inner diameter D1: 2mm Number of spiral groove turns: 2 or 4 Spiral groove 50 pitch P: 4.50 or 2.75 mm Inner diameter D2 of liquid inlet 3: 4.5mm Inner diameter D3 of liquid outlet 4: 2.5mm, 2.2mm, 2.0mm or 3.0mm Length of the inlet side tapered section 21: 5 mm Length of the outlet side tapered section 22: 7 mm Mesh material 63: 3-ply laminated mesh size #400 (mesh size 0.034 mm, opening rate 27.8%)

[0086] The gas introduction passage 20 is formed as follows. Tip shape: As shown in Figure 14. The inner diameter of the main body 20A is 0.5 mm. The length CL of the tapered section is 1.5 mm. The length TL of the pinhole 20S forming the gas outlet 20T is 0.15 mm, and the inner diameter TD is 0.1 mm. Angle λ2 between axis Q and axis O: 45° (see Figure 5) The opening position of the gas outlet 20T is one of the following three types or a combination thereof: Upstream side: The bottom position of the spiral groove 50 on the first turn from the starting point (FIG. 5: 20(U)) Downstream side: The bottom position of the spiral groove 50, which is 1 / 4 of a turn back from the end point of the spiral groove 50 (FIG. 5: 20C) Outlet side tapered portion: The inner surface position of the outlet side tapered portion 22, which is 2.5 mm away from the liquid outlet 4 in the direction of the axis O (Fig. 13: 20(D)) The specific dimensions of each prototype and the position of the gas introduction passage 20 are summarized in Table 2.

[0087] The tap water treatment device 100 described above was connected to a tap unit as shown in Figure 2, and the outlet water flow rate was adjusted to 4 L / min by manually operating the water flow valve 91B. The number formation density and number bubble size distribution of the resulting treated water were measured using a laser scattering nanoparticle size distribution measurement device (Shimadzu Corporation: SALD-7500nano). Note that the bubble size measurement of the treated water was performed 15 seconds after the water intake. The results are summarized in Table 2.

[0088] [Table 2]

[0089] When the pitch of the spiral grooves 50 is set to 4.5 mm, for example, a comparison with the results obtained when nozzle No. 3 in Table 1 is used, which does not have a gas introduction passage 20, reveals that the density of ultra-fine bubbles with a diameter of 0.3 μm or less is improved by using nozzles Nos. 111 to 115, which are equipped with a gas introduction passage 20. In particular, when nozzle No. 111, which has a gas introduction passage 20 only on the upstream side, is used, the density of ultra-fine bubbles formed is 3.3 billion bubbles / cc, which is 14 times higher than that of nozzle No. 3, which does not have a gas introduction passage 20.

[0090] On the other hand, when nozzle No. 112, which has a gas introduction passage 20 only on the downstream side, is used, the density of ultra-fine bubbles formed is roughly the same as when nozzle No. 3 in Table 1, which does not have a gas introduction passage 20, is used, but the density of bubbles in the fine bubble range exceeding 1 μm is higher than when nozzle No. 111 is used. Furthermore, when nozzles Nos. 113 and 114, which have gas introduction passages 20 on both the downstream and downstream sides (or the tapered outlet section), are used, the density of ultra-fine bubbles formed is lower than when nozzle No. 111 is used, but it is clear that there is a significant increase in fine bubbles in the bubble diameter range equivalent to ultra-fine bubbles of 1 to 5 μm. Fine bubbles in this range rise relatively slowly, which greatly contributes to the clouding of the collected water and their sustainability.

[0091] Furthermore, when the pitch P of the spiral grooves 50 was set to 2.75 mm and the depth d of the spiral grooves 50 to 0.5 mm, by providing gas introduction passages 20 on both the downstream and downstream sides (number 116), the density of ultra-fine bubbles formed dramatically increased to 6.4 billion bubbles / cc, more than 20 times that of nozzle number 2 in Table 1, which does not have a gas introduction passage 20. This is thought to be related to the optimization of the pitch P of the spiral grooves 50, which further increases the formation of swirling flow. On the other hand, for nozzle number 117, in which the opening area of ​​the liquid outlet 4 is less than 1.2 times the axial cross-sectional area of ​​the inter-groove region 52 of the cavitation treatment unit 5 at the minimum inner diameter position, and nozzle number 118, in which it is more than twice that, the density of ultra-fine bubbles or fine bubbles formed was slightly lower than that of nozzle number 116, despite the provision of a gas introduction passage on the downstream side.

[0092] Although various embodiments of the present invention have been described above, the present invention is not limited to these, and technical elements other than the essential constituent elements set forth in the claims can be implemented in a manner selected as appropriate. [Explanation of symbols]

[0093] 1 Liquid Processing Nozzle 2 Liquid flow path 3 liquid inlet 4 liquid outlet 5. Cavitation treatment section 7 Gas relay space 10 Nozzle body 20 Gas introduction passage 20A main body 20B Reduced diameter part 20E Gas inlet 20P Base end side 20S pinhole part 20T Gas Outlet 21 Inlet side tapered section 22 Outlet side tapered section 26 Space forming recess 31,32 Groove 31,32 Seal ring 33 Seal ring 40 Main casing 40a stepped surface 41 Counterbore joint 42 Female thread joint 43 Seal ring 44 Nozzle accommodation hole 44a Support flange 45 Body side outlet hole 46 Casing gas flow path 46E Gas inlet 46T Gas outlet 47 Groove 47A Gas Induction Gap 50 spiral groove 51 Groove bottom 52 Groove area 60 Outlet Cap 60b female thread 61 Water outlet 62 Support flange 63 Mesh material 64 Outlet sleeve 64b Male thread 70 Elastic ring for preventing backflow 70c sealing surface 91 Water faucet unit 92 Water valve 100 Tap water treatment equipment DXW treated water O axis Q axis

Claims

1. A liquid processing nozzle that is incorporated into a flow path through which a liquid containing dissolved gas flows, and that performs cavitation treatment on the liquid to precipitate the dissolved gas as bubbles, The liquid treatment nozzle has a nozzle body in which a through-shaped liquid flow path is formed, with a liquid inlet opening at one end face and a liquid outlet opening at the other end face, and the nozzle body has a cavitation treatment section in which at least a portion of the axial direction of the inner surface of the liquid flow path is engraved with a spiral groove of at least one revolution with the axis as the spiral center line for precipitating the dissolved gas as bubbles, and in the liquid flow path, an outlet-side tapered section is formed downstream of the cavitation treatment section, the inner diameter of which gradually increases from the outlet of the cavitation treatment section toward the liquid outlet, and an inlet-side tapered section is formed upstream of the cavitation treatment section, the inner diameter of which gradually decreases from the liquid inlet toward the inlet of the cavitation treatment section.

2. A liquid processing nozzle as described in claim 1, wherein, on the inner surface of the liquid flow path that forms the cavitation treatment section, when the area that divides adjacent circumferential portions of the spiral groove in the axial direction is defined as an inter-groove area and the minimum inner diameter of the inter-groove area is defined as the inter-groove area inner diameter, the engraving pitch of the spiral groove in the axial direction is set to be larger than the inter-groove area inner diameter.

3. 3. A liquid treatment nozzle according to claim 2, wherein the depth of said spiral groove is set smaller than said engraving pitch.

4. 4. The liquid treatment nozzle according to claim 2, wherein the depth of the spiral groove is set to 10% or more of the inner diameter of the inter-groove region.

5. A liquid processing nozzle as described in any one of claims 2 to 4, wherein the inter-groove region is formed flat in a cross section including the axis, and the spiral groove is formed in a shape that bulges outward from the inter-groove region.

6. The liquid treatment nozzle according to claim 5 , wherein the inter-groove area is formed in the shape of a cylindrical surface.

7. 7. The liquid treatment nozzle according to claim 5, wherein the inter-groove region is formed so that its width in the axial direction is larger than the width of the spiral groove.

8. A liquid processing nozzle described in any one of claims 5 to 7, wherein the depth of the spiral groove is set to a value of 10% to 40% of the inner diameter of the inter-groove region, and 80% to 120% of the width of the spiral groove.

9. A liquid processing nozzle as described in any one of claims 2 to 8, wherein the spiral groove is formed to have an outer shape in which the groove depth continuously decreases from the groove bottom position toward the adjacent inter-groove region in the axial direction.

10. A liquid processing nozzle as described in any one of claims 2 to 9, wherein L / D1 is set to be 1 or more and 10 or less, where L is the section length of the cavitation treatment section and D1 is the inner diameter of the groove region.

11. 11. The liquid processing nozzle according to claim 1, wherein the spiral groove is formed in the cavitation treatment section for two or more turns.

12. A liquid processing nozzle as described in any one of claims 1 to 11, wherein the nozzle body has a gas introduction passage formed therein, one end of which opens to the outer surface of the nozzle body and the other end of which is connected to the spiral groove of the cavitation treatment unit, for sucking gas from outside the nozzle body into the spiral groove or the outlet side tapered portion.

13. 13. The liquid processing nozzle according to claim 12, wherein the gas introduction passage is open to communicate with the cavitation treatment section in a half section upstream in the axial direction.

14. 14. The liquid processing nozzle according to claim 12 or 13, wherein the gas introduction passage is open to a bottom of the spiral groove.

15. 15. The liquid processing nozzle according to claim 1, wherein the outlet side tapered portion is formed so that the section length is greater than the cutting pitch of the spiral groove.

16. A liquid processing nozzle described in any one of claims 1 to 15, wherein the liquid outlet of the outlet side tapered portion is formed so as to have an opening area that is 1.2 to 2 times the axial cross-sectional area at the minimum inner diameter position of the groove region of the cavitation treatment portion.

17. A liquid processing nozzle as described in any one of claims 1 to 16, wherein the nozzle body has a gas introduction passage formed therein, one end of which opens to the outer surface of the nozzle body and the other end of which is connected to either the downstream half section in the axial direction of the cavitation treatment section or the outlet side tapered section, for sucking gas from outside the nozzle body into the spiral groove or the outlet side tapered section.

18. A liquid processing nozzle as described in any one of claims 1 to 17, wherein the inner diameter of the inlet side tapered portion gradually decreases at a greater gradient than that of the outlet side tapered portion.

19. 19. The liquid processing nozzle according to claim 1, wherein the liquid inlet of the inlet-side tapered portion is formed to have a larger diameter than the liquid outlet of the outlet-side tapered portion.

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